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1. The Hi-GAL catalogue of dusty filamentary structures in the Galactic plane

Author: Eugenio Schisano, S Molinari, D Elia, M Benedettini, L Olmi, S Pezzuto, A Traficante, M Brescia, S Cavuoti, A M di Giorgio, S J Liu, T J T Moore, A Noriega-Crespo, G Riccio, A Baldeschi, U Becciani, N Peretto, M Merello, F Vitello, A Zavagno, M T Beltrán, L Cambrésy, D J Eden, G Li Causi, M Molinaro, P Palmeirim, E Sciacca, L Testi, G Umana, and A P Whitworth
Published: 2019
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2. The SQUALO project (Star formation in QUiescent And Luminous Objects) I: clump-fed accretion mechanism in high-mass star-forming objects

Author: A Traficante, B M Jones, A Avison, G A Fuller, M Benedettini, D Elia, S Molinari, N Peretto, S Pezzuto, T Pillai, K L J Rygl, E Schisano, and R J Smith
Subjects: Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: The formation mechanism of the most massive stars is far from completely understood. It is still unclear if the formation is core-fed or clump-fed, i.e. if the process is an extension of what happens in low-mass stars, or if the process is more dynamical such as a continuous, multi-scale accretion from the gas at parsec (or even larger) scales. In this context we introduce the SQUALO project, an ALMA 1.3 mm and 3 mm survey designed to investigate the properties of 13 massive clumps selected at various evolutionary stages, with the common feature that they all show evidence for accretion at the clump scale. In this work we present the results obtained from the 1.3 mm continuum data. Our observations identify 55 objects with masses in the range 0.4, 25 pages, 15 Figures, 9 Tables. Accepted for publication in MNRAS
Published: 2023

3. HCN/HNC chemistry in shocks

Author: E. Mendoza, Serena Viti, Linda Podio, Rafael Bachiller, P. R. Rivera-Ortiz, Bertrand Lefloch, Charlotte Vastel, M. Benedettini, Gemma Busquet, Jacques Raymond Daniel Lépine, C. Codella, A Schutzer, Agence Nationale de la Recherche (France), European Commission, European Research Council, Fundações de Amparo à Pesquisa (Brasil), Ministerio de Ciencia, Innovación y Universidades (España), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), University College of London [London] (UCL), Centro de Investigaciones Energéticas Medioambientales y Tecnológicas [Madrid] (CIEMAT), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), and INAF - Osservatorio Astrofisico di Arcetri (OAA)
Subjects: FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: abundances, jets and outflow -ISM, Jets and Outflows, Methods: observational, Abundance (ecology), 0103 physical sciences, astrochemistry -methods, Radiative transfer, Methods, Protostar, Molecule, Isotopologue, observational [Methods], Abundances, 010306 general physics, 010303 astronomy & astrophysics, Observational, molecules [ISM], ISM, Astrochemistry, abundances [ISM], Molecular line, Chemistry, jets and outflows [ISM], Molecular cloud, molecules -ISM, Astronomy and Astrophysics, observational -ISM, Molecules, Astrophysics - Astrophysics of Galaxies, ISM: molecules, ISM: jets and outflows, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Excitation
Abstract: HCN and its isomer HNC play an important role in molecular cloud chemistry and the formation of more complex molecules. We investigate here the impact of protostellar shocks on the HCN and HNC abundances from high-sensitivity IRAM 30m observations of the prototypical shock region L1157-B1 and the envelope of the associated Class 0 protostar, as a proxy for the pre-shock gas. The isotopologues H$^{12}$CN, HN$^{12}$C, H$^{13}$CN, HN$^{13}$C, HC$^{15}$N, H$^{15}$NC, DCN and DNC were all detected towards both regions. Abundances and excitation conditions were obtained from radiative transfer analysis of molecular line emission under the assumption of Local Thermodynamical Equilibrium. In the pre-shock gas, the abundances of the HCN and HNC isotopologues are similar to those encountered in dark clouds, with a HCN/HNC abundance ratio $\approx 1$ for all isotopologues. A strong D-enrichment (D/H$\approx 0.06$) is measured in the pre-shock gas. There is no evidence of $^{15}$N fractionation neither in the quiescent nor in the shocked gas. At the passage of the shock, the HCN and HNC abundances increase in the gas phase in different manners so that the HCN/HNC relative abundance ratio increases by a factor 20. The gas-grain chemical and shock model UCLCHEM allows us to reproduce the observed trends for a C-type shock with pre-shock density $n$(H)= $10^5$cm$^{-3}$ and shock velocity $V_s= 40$km/s. We conclude that the HCN/HNC variations across the shock are mainly caused by the sputtering of the grain mantle material in relation with the history of the grain ices., Comment: 14 pages, 7 figures. Accepted for publication in MNRAS
Published: 2021

4. Seeds of Life in Space (SOLIS)

Author: R. Neri, C. Codella, M. Benedettini, Cecilia Ceccarelli, Linda Podio, Bertrand Lefloch, Gemma Busquet, Francesco Fontani, S. Viti, Charlotte Vastel, Ana López-Sepulcre, E. Bianchi, S. Spezzano, and Paola Caselli
Subjects: Shock wave, Physics, Solar System, 010504 meteorology & atmospheric sciences, Period (periodic table), Star (game theory), Astrophysics - astrophysics of galaxies, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Space (mathematics), 01 natural sciences, Isotopes of nitrogen, ISM: molecules, Interstellar medium, ISM: jets and outflows, ISM: individual objects: L1157, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The isotopic ratio of nitrogen presents a wide range of values in the Solar System and in star forming system whose origin is still unclear. Chemical reactions in the gas phase are one of the possible processes that could modify the $^{14}$N/$^{15}$N ratio. We aim at investigating if and how the passage of a shock wave in the interstellar medium, can affect the relative fraction of nitrogen isotopes. The ideal place for such a study is the L1157 outflow, where several shocked clumps are present. We present the first measurement of the $^{14}$N/$^{15}$N ratio in the two shocked clumps, B1 and B0, of the protostellar outflow L1157, derived from the interferomteric maps of the H$^{13}$CN(1-0) and the HC$^{15}$N(1-0) lines. In B1, we find that the H$^{13}$CN(1-0) and HC$^{15}$N(1-0) emission traces the front of the clump, with averaged column density of $N$(H$^{13}$CN) $\sim$ 7$\times$10$^{12}$ cm$^{-2}$ and $N$(HC$^{15}$N) $\sim$ 2$\times$10$^{12}$ cm$^{-2}$. In this region the ratio H$^{13}$CN(1-0)/HC$^{15}$N(1-0) is quite uniform with an average value of $\sim$ 5$\pm$1. The same average value is also measured in the smaller clump B0e. Assuming the standard $^{12}$C/$^{13}$C = 68, we obtain $^{14}$N/$^{15}$N = 340$\pm$70, similar to those usually found in prestellar cores and protostars. We analysed the prediction of a chemical shock model for several shock conditions and we found that the nitrogen and carbon fractionations do not vary much for the first period after the shock. The observed H$^{13}$CN/HC$^{15}$N can be reproduced by a non-dissociative, C-type shock with parameters in agreement with previous modelling of L1157-B1. Both observations and chemical models indicate that the shock propagation does not affect the nitrogen isotopic ratio that remains similar to that measured in lower temperature gas in prestellar cores and in protostellar envelopes., 7 pages, 6 figures
Published: 2021

5. Molecular cloud catalogue from 13CO (1-0) data of the Forgotten Quadrant Survey

Author: M. T. Beltrán, K. L. J. Rygl, Alessio Traficante, Adriano Baldeschi, Luca Olmi, Jan Brand, Manuel Merello, S. J. Liu, M. Benedettini, Stefano Pezzuto, Eugenio Schisano, Francesco Fontani, Riccardo Cesaroni, Leonardo Testi, Sergio Molinari, and Davide Elia
Subjects: Physics, Star formation, Molecular cloud, Milky Way, Velocity dispersion, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galactic plane, Astrophysics - Astrophysics of Galaxies, Virial theorem, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Optical depth (astrophysics), Astrophysics::Galaxy Astrophysics
Abstract: New-generation spectroscopic surveys of the Milky Way plane have been revealing the structure of the interstellar medium, allowing the simultaneous study of dense structures from single star-forming objects or systems to entire spiral arms. We present the catalogue of molecular clouds extracted from the $^{13}$CO(1-0) data cubes of the Forgotten Quadrant Survey, which mapped the Galactic plane in the range 220\deg, Comment: 14 pages, 11 figures, accepted by Astronomy and Astrophysics
Published: 2021

6. The census of dense cores in the Serpens region from the Herschel Gould Belt Survey

Author: Vera Konyves, E. Fiorellino, Stefano Pezzuto, M. Benedettini, Derek Ward-Thompson, Frédérique Motte, Ph. André, Andrea Bracco, J. Di Francesco, Doris Arzoumanian, Jason M. Kirk, Sylvain Bontemps, Eugenio Schisano, Sergio Molinari, Davide Elia, Alexander Men'shchikov, FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, infrared: ISM, Initial mass function, stars: formation, Serpens, 010308 nuclear & particles physics, ISM: structure, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, F500, 01 natural sciences, ISM: clouds, Astrophysics - Astrophysics of Galaxies, submillimetre: ISM, ISM: individual (Serpens), ISM: individual objects (Serpens), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The Herschel Gould Belt survey mapped the nearby (d < 500 pc) star-forming regions to understand better how the prestellar phase influences the star formation process. Here we report a complete census of dense cores in a 15 deg2 area of the Serpens star-forming region located between d=420 pc and 484 pc. The PACS and SPIRE cameras imaged this cloud from 70micron to 500micron. With the multi-wavelength source extraction algorithm getsources, we extract 833 sources, of which 709 are starless cores and 124 are candidate proto-stellar cores. We obtain temperatures and masses for all the sample, classifying the starless cores in 604 prestellar cores and 105 unbound cores. Our census of sources is 80% complete for masses larger than 0.8 Msun overall. We produce the core mass function (CMF) and compare it with the initial mass function (IMF). The prestellar CMF is consistent with log-normal trend up to 2 Msun, after which it follows a power-law with slope of -2.05+/-0.34. The tail of its CMF is steeper but still compatible with the IMF for the region we studied in this work. We also extract the filaments network of the Serpens region, finding that 81% of prestellar cores lie on filamentary structures. The spatial association between cores and filamentary structure supports the paradigm, suggested by otherHerschelobservations, that prestellar cores mostly form on filaments. Serpens is confirmed to be a young, low-mass and active star-forming region., 22 pages, 17 figures
Published: 2020

7. Physical properties of the ambient medium and of dense cores in the Perseus star-forming region derived from Herschel Gould Belt Survey observations

Author: Stefano Pezzuto, Alexander Men'shchikov, Ph. André, J. Di Francesco, Christine D. Wilson, Sylvain Bontemps, L. Piccotti, Sarah Sadavoy, Frédérique Motte, Vera Konyves, P. Palmeirim, E. Fiorellino, Nicola Schneider, Jason M. Kirk, L. Spinoglio, Davide Elia, J.-Ph. Bernard, Eugenio Schisano, Doris Arzoumanian, G. Li Causi, M. Benedettini, Derek Ward-Thompson, Bilal Ladjelate, FEMIS 2021, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Initial mass function, 010504 meteorology & atmospheric sciences, Extinction (astronomy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Power law, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Wavelength, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Right ascension
Abstract: (Abridged) In this paper, we present analyses of images taken with the Herschel ESA satellite from 70mu to 500mu. We first constructed column density and dust temperature maps. Next, we identified compact cores in the maps, and characterize the cores using modified blackbody fits to their SEDs: we identified 684 starless cores, of which 199 are bound and potential prestellar cores, and 132 protostars. We also matched the Herschel-identified young stars with GAIA sources to model distance variations across the Perseus cloud. We measure a linear gradient function with right ascension and declination for the entire cloud. From the SED fits, mass and temperature of cores were derived. The core mass function can be modelled with a log-normal distribution that peaks at 0.82~$M_\sun$ suggesting a star formation efficiency of 0.30. The high-mass tail can be modelled with a power law of slope $\sim-2.32$, close to the Salpeter's value. We also identify the filamentary structure of Perseus, confirming that stars form preferentially in filaments. We find that the majority of filaments where star formation is ongoing are transcritical against their own internal gravity because their linear masses are below the critical limit of 16~$M_\sun$pc$^{-1}$ above which we expect filaments to collapse. We find a possible explanation for this result, showing that a filament with a linear mass as low as 8~$M_\sun$pc$^{-1}$ can be already unstable. We confirm a linear relation between star formation efficiency and slope of dust probability density function and a similar relation is also seen with the core formation efficiency. We derive a lifetime for the prestellar core phase of $1.69\pm0.52$~Myr for Perseus but different regions have a wide range in prestellar core fractions, hint that star-formation has started only recently in some clumps. We also derive a free-fall time for prestellar cores of 0.16~Myr., Comparison with Zari et al's (2016) work improved once Eleonora Zari told us that, contrarily to what we wrote, their data are publicly available (this was not written in the first version of their paper put on arxiv, then our misunderstaning). The modification is small, a paragraph on page 11, and does not have any impact on the content of the paper. Modification allowed by A&A editor
Published: 2020

8. The Hi-GAL catalogue of dusty filamentary structures in the Galactic Plane

Author: Stefano Pezzuto, Alberto Noriega-Crespo, Manuel Merello, David Eden, Giuseppe Riccio, Luca Olmi, Fabio Vitello, Nicolas Peretto, Sergio Molinari, Eva Sciacca, Eugenio Schisano, G. Li Causi, P. Palmeirim, Annie Zavagno, M. T. Beltrán, A. M. di Giorgio, M. Benedettini, Anthony Peter Whitworth, Toby J. T. Moore, Massimo Brescia, Davide Elia, Marco Molinaro, Leonardo Testi, Ugo Becciani, L. Cambresy, G. Umana, A. Baldeschi, S. J. Liu, Alessio Traficante, Stefano Cavuoti, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Capodimonte (OAC), University of Naples Federico II, Liverpool John Moores University (LJMU), Space Telescope Science Institute (STSci), INAF - Osservatorio Astrofisico di Catania (OACT), School of Physics and Astronomy [Cardiff], Cardiff University, Departamento de Astronomia (DAS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Roma (OAR), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica e Ciências do Espaço (IASTRO), European Southern Observatory (ESO), Schisano, E., Molinari, S., Elia, D., Benedettini, M., Olmi, L., Pezzuto, S., Traficante, A., Brescia, M., Cavuoti, S., di Giorgio, A. M., Liu, S. J., Moore, T. J. T., Noriega-Crespo, A., Riccio, G., Baldeschi, A., Becciani, U., Peretto, N., Merello, M., Vitello, F., Zavagno, A., Beltran, M. T., Cambresy, L., Eden, D. J., Li Causi, G., Molinaro, M., Palmeirim, P., Sciacca, E., Testi, L., Umana, G., Whitworth, A. P., and University of Naples Federico II = Università degli studi di Napoli Federico II
Subjects: Milky Way, Stars: formation, Extinction (astronomy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Protein filament, ISM: cloud, 0103 physical sciences, Submillimeter: ISM, 010303 astronomy & astrophysics, Galaxy: structure, Solar and Stellar Astrophysics (astro-ph.SR), ISM, Astrophysics::Galaxy Astrophysics, QC, ISM: general, QB, Physics, Infrared: ISM, Spiral galaxy, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, Molecular cloud, SM: clouds, Astronomy and Astrophysics, Dust, Extinction, Galactic plane, Galaxy: local interstellar matter, Astrophysics - Astrophysics of Galaxies, Galaxy, ISM: dust, Galaxy:structure, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: The recent data collected by {\it Herschel} have confirmed that interstellar structures with filamentary shape are ubiquitously present in the Milky Way. Filaments are thought to be formed by several physical mechanisms acting from the large Galactic scales down to the sub-pc fractions of molecular clouds, and they might represent a possible link between star formation and the large-scale structure of the Galaxy. In order to study this potential link, a statistically significant sample of filaments spread throughout the Galaxy is required. In this work we present the first catalogue of $32,059$ candidate filaments automatically identified in the Hi-GAL survey of the entire Galactic Plane. For these objects we determined morphological (length, $l^{a}$, and geometrical shape) and physical (average column density, $N_{\rm H_{2}}$, and average temperature, $T$) properties. We identified filaments with a wide range of properties: 2$'$\,$\leq l^{a}\leq$\, 100$'$, $10^{20} \leq N_{\rm H_{2}} \leq 10^{23}$\,cm$^{-2}$ and $10 \leq T\leq$ 35\,K. We discuss their association with the Hi-GAL compact sources, finding that the most tenuous (and stable) structures do not host any major condensation and we also assign a distance to $\sim 18,400$ filaments for which we determine mass, physical size, stability conditions and Galactic distribution. When compared to the spiral arms structure, we find no significant difference between the physical properties of on-arm and inter-arm filaments. We compared our sample with previous studies, finding that our Hi-GAL filament catalogue represents a significant extension in terms of Galactic coverage and sensitivity. This catalogue represents an unique and important tool for future studies devoted to understanding the filament life-cycle., 38 pages, 29 figures, 3 appendices
Published: 2020

9. The Forgotten Quadrant Survey. 12CO and 13CO (1-0) survey of the Galactic plane in the range 220° <l <240° -2.°5 < b < 0°

Author: Sergio Molinari, M. T. Beltrán, Eugenio Schisano, Kazi L.J. Rygl, Leonardo Testi, Riccardo Cesaroni, Stefano Pezzuto, Davide Elia, Francesco Fontani, Alessio Traficante, Jan Brand, A. Baldeschi, Luca Olmi, M. Benedettini, Manuel Merello, and ITA
Subjects: Physics, 010308 nuclear & particles physics, Molecular cloud, Galactic quadrant, Astronomy and Astrophysics, Astrophysics, Galactic plane, 01 natural sciences, Spectral line, Galaxy, Interstellar medium, Stars, Space and Planetary Science, 0103 physical sciences, Spectral resolution, 010303 astronomy & astrophysics
Abstract: Aims. We present the Forgotten Quadrant Survey (FQS), an ESO large project that used the 12 m antenna of the Arizona Radio Observatory to map the Galactic plane in the range 220° < l < 240° and −2.°5 < b < 0°, both in 12CO (1–0) and 13CO (1–0), at a spectral resolution of 0.65 km s−1 and 0.26 km s−1. Methods. We used the (1–0) transition of carbon monoxide to trace the molecular component of the interstellar medium. Our data set allows us to easily identify how the molecular dense gas is organised at different spatial scales: from the giant clouds with their denser filamentary networks, down to the clumps and cores that host the new-born stars and to obtain reliable estimates of their key physical parameters such as size and mass. Results. We present the first release of the data of the FQS survey and discuss their quality. Spectra with 0.65 km s−1 velocity channels have noise ranging from 0.8 K to 1.3 K for 12CO (1–0) and from 0.3 K to 0.6 K for 13CO (1–0). In this first paper, we used the 12CO (1–0) spectral cubes to produce a catalogue of 263 molecular clouds. The clouds are grouped in three main structures corresponding to the Local, Perseus, and Outer arms up to a distance of ∼8.6 kpc from the Sun. This is the first self-consistent statistical catalogue of molecular clouds of the outer Galaxy obtained with a subarcminute spatial resolution and therefore able to detect not only the classical giant molecular clouds, but also the small clouds and to resolve the cloud structure at the sub-parsec scale up to a distance of a few kiloparsec. We found two classes of objects: structures with sizes above a few parsecs that are typical molecular clouds and may be self-gravitating, and subparsec structures that cannot be in gravitational equilibrium and are likely transient or confined by external pressure. We used the ratio between the Herschel H2 column density and the integrated intensity of the CO lines to calculate the CO conversion factor and we found mean values of (3.3 ± 1.4) × 1020 cm−2 (K km s−1)−1 and (1.2 ± 0.4) × 1021 cm−2 (K km s−1)−1, for 12CO (1–0) and 13CO (1–0), respectively. Conclusions. The FQS contributes to the general effort in producing a new generation of high-quality spectroscopic data for the Galactic plane in the less-studied third Galactic quadrant toward the outer Galaxy. The FQS has produced a data set of great legacy value, largely improving the data quality both in terms of sensitivity and spatial resolution over previous data sets.
Published: 2020

10. Herschel-HOBYS study of the earliest phases of high-mass star formation in NGC 6357

Author: Stefano Pezzuto, M. Figueira, D. Russeil, Pierre Didelon, Kazi L.J. Rygl, Annie Zavagno, Sylvain Bontemps, J. Di Francesco, Davide Elia, M. Benedettini, Nicola Schneider, G. J. White, Eugenio Schisano, Frédérique Motte, Vera Konyves, Ph. André, T. Nony, Luigi Spinoglio, Alexander Men'shchikov, L. D. Anderson, J. Tigé, Q. Nguyen Luong, ITA, GBR, FRA, CAN, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), University of Cologne, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2019, Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Center for Gravitational Wave Astronomy (CGWA), University of Texas Rio Grande Valley [Brownsville, TX] (UTRGV), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Korea Astronomy and Space Science Institute (KASI), Okayama University [Okayama], NAOJ Chile Observatory, National Astronomical Observatory of Japan (NAOJ), INAF - Osservatorio Astronomico di Bologna (OABO), Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Programme National de Physique Stellaire' (PNPS) and Programme 'Physique et Chime du Milieu Interstellaire' (PCMI) of CNRS/INSU, France, ANR-16-CE92-0035,GENESIS,GENeration et Evolution des Structures du milieu InterStellaire(2016), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), and Okayama University
Subjects: Physics, education.field_of_study, stars: formation, 010504 meteorology & atmospheric sciences, Star formation, F510, Population, Astronomy and Astrophysics, Astrophysics, F500, Star (graph theory), 01 natural sciences, stars: massive, Spire, Stars, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, 0103 physical sciences, High mass, Spectral energy distribution, Protostar, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Aims: To constrain models of high-mass star formation it is important to identify the massive dense cores (MDCs) that are able to form high-mass star(s). This is one of the purposes of the Herschel/HOBYS key programme. Here, we carry out the census and characterise of the properties of the MDCs population of the NGC 6357 H II region. Methods: Our study is based on the Herschel/PACS and SPIRE 70-500 μm images of NGC 6357 complemented with (sub-)millimetre and mid-infrared data. We followed the procedure established by the Herschel/HOBYS consortium to extract ~0.1 pc massive dense cores using the getsources software. We estimated their physical parameters (temperatures, masses, luminosities) from spectral energy distribution (SED) fitting. Results: We obtain a complete census of 23 massive dense cores, amongst which one is found to be IR-quiet and twelve are starless, representing very early stages of the star-formation process. Focussing on the starless MDCs, we have considered their evolutionary status, and suggest that only five of them are likely to form a high-mass star. Conclusions: We find that, contrarily to the case in NGC 6334, the NGC 6357 region does not exhibit any ridge or hub features that are believed to be crucial to the massive star formation process. This study adds support for an empirical model in which massive dense cores and protostars simultaneously accrete mass from the surrounding filaments. In addition, the massive star formation in NGC 6357 seems to have stopped and the hottest stars in Pismis 24 have disrupted the filaments. Full Table C1, Tables C2-C5, the reduced Herschel FITS images and the column density FITS image are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A134 Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Published: 2019

11. The Herschel view of the dense core population in the Ophiuchus molecular cloud

Author: J. Di Francesco, P. Palmeirim, M. Benedettini, Andrea Bracco, Nicola Schneider, Vera Konyves, Frédérique Motte, Jason M. Kirk, Stefano Pezzuto, Y. Shimajiri, Ph. André, Alexander Men'shchikov, Doris Arzoumanian, A. Roy, E. Fiorellino, Derek Ward-Thompson, Bilal Ladjelate, Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Kagoshima University, National Astronomical Observatory of Japan (NAOJ), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), National Research Council of Canada (NRC), European Southern Observatory (ESO), Università degli Studi di Roma Tor Vergata [Roma], Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, support from the French national programs of CNRS/INSU on stellar and ISM physics (PNPS and PCMI)., the Herschel Gould Belt Survey Team, ANR-11-BS56-0010,STARFICH,Vers une vision unifiée de la formation stellaire dans les galaxies : Origine de la structure filamentaire du milieu interstellaire, des cœurs pré-stellaires et des amas protostellaires vus avec Herschel(2011), ANR-16-CE92-0035,GENESIS,GENeration et Evolution des Structures du milieu InterStellaire(2016), European Project: 291294,EC:FP7:ERC,ERC-2011-ADG_20110209,ORISTARS(2012), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-École normale supérieure - Paris (ENS Paris)
Subjects: 010504 meteorology & atmospheric sciences, ISM: structure, Young stellar object, Continuum (design consultancy), Population, FOS: Physical sciences, Context (language use), Astrophysics, ISM: clouds, 01 natural sciences, 0103 physical sciences, education, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, education.field_of_study, stars: formation, Star formation, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Ophiuchus, submillimeter: ISM, ISM: individual objects: Ophiuchus Complex, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Herschel observations of nearby clouds in the Gould Belt support a paradigm for low-mass star formation, starting with the generation of molecular filaments, followed by filament fragmentation, and the concentration of mass into self-gravitating prestellar cores. With the unique far-infrared and submillimeter continuum imaging capabilities of the Herschel Space observatory, the closeby (d = 139 pc) Ophiuchus cloud was mapped at five wavelengths from 70 ${\mu}m$ to 500 ${\mu}m$ with the aim of providing a complete census of dense cores in this region, including unbound starless cores, bound prestellar cores, and protostellar cores. Taking advantage of the high dynamic range and multi-wavelength nature of the Herschel data, we used the multi-scale decomposition algorithms getsources and getfilaments to identify a complete sample of dense cores and filaments in the cloud and study their properties. The densest clouds of the Ophiuchus complex, L1688 and L1689, which thus far are only indirectly described as filamentary regions owing to the spatial distribution of their young stellar objects (YSOs), are confirmed to be dominated by filamentary structures. The tight correlation observed between prestellar cores and filamentary structures in L1688 and L1689 supports the view that solar-type star formation occurs primarily in dense filaments. While the sub clouds of the complex show disparities, L1689 being less efficient than L1688 at forming stars when considering their total mass budgets, both sub clouds share almost the same prestellar core formation efficiency in dense molecular gas. We also find evidence in the Herschel data for a remarkable concentric geometrical configuration in L1688 which is dominated by up to three arc-like compression fronts and presumably created by shockwave events emanating from the Sco OB2 association, including the neighboring massive (O9V) star ${\sigma}$ Sco., Comment: Accepted for publication in A&A
Published: 2020

12. A search for Cyanopolyynes in L1157-B1

Author: Claudio Codella, E. Mendoza, Ali A. Jaber, Bertrand Lefloch, Rafael Bachiller, Izaskun Jiménez-Serra, Cecilia Ceccarelli, Jacques Raymond Daniel Lépine, Claudine Kahane, M. Benedettini, Heloisa M. Boechat-Roberty, Serena Viti, and Linda Podio
Subjects: Physics, Astrochemistry, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Spectral line, Shock (mechanics), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Radiative transfer, Protostar, Isotopologue, FORMAÇÃO DE ESTRELAS, 010303 astronomy & astrophysics, Envelope (waves), Line (formation)
Abstract: We present here a systematic search for cyanopolyynes in the shock region L1157-B1 and its associated protostar L1157-mm in the framework of the Large Program "Astrochemical Surveys At IRAM" (ASAI), dedicated to chemical surveys of solar-type star forming regions with the IRAM 30m telescope. Observations of the millimeter windows between 72 and 272 GHz permitted the detection of HC$_3$N and its $^{13}$C isotopologues, and HC$_5$N (for the first time in a protostellar shock region). In the shock, analysis of the line profiles shows that the emission arises from the outflow cavities associated with L1157-B1 and L1157-B2. Molecular abundances and excitation conditions were obtained from analysis of the Spectral Line Energy Distributions under the assumption of Local Thermodynamical Equilibrium or using a radiative transfer code in the Large Velocity Gradient approximation. Towards L1157mm, the HC$_3$N emission arises from the cold envelope ($T_{rot}=10$ K) and a higher-excitation region ($T_{rot}$= $31$ K) of smaller extent around the protostar. We did not find any evidence of $^{13}$C or D fractionation enrichment towards L1157-B1. We obtain a relative abundance ratio HC$_3$N/HC$_5$N of 3.3 in the shocked gas. We find an increase by a factor of 30 of the HC$_3$N abundance between the envelope of L1157-mm and the shock region itself. Altogether, these results are consistent with a scenario in which the bulk of HC$_3$N was produced by means of gas phase reactions in the passage of the shock. This scenario is supported by the predictions of a parametric shock code coupled with the chemical model UCL_CHEM., Comment: 13 pages, 12 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal
Published: 2018
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13. Silicon-bearing molecules in the shock L1157-B1: first detection of SiS around a Sun-like protostar

Author: Claudio Codella, Francesco Fontani, M. Benedettini, Rafael Bachiller, José Cernicharo, Bertrand Lefloch, Marzio Rosi, Linda Podio, Cecilia Ceccarelli, Noelia Faginas-Lago, Nadia Balucani, Antoine Gusdorf, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Università degli Studi di Perugia = University of Perugia (UNIPG), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), INAF - Osservatorio Astronomico di Brera (OAB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Ingegneria Civile ed Ambientale, Instituto Geográfico Nacional (España), Institut national des sciences de l'Univers (France), Centre National D'Etudes Spatiales (France), Centre National de la Recherche Scientifique (France), Max Planck Society, Università degli Studi di Perugia (UNIPG), and École normale supérieure - Paris (ENS Paris)
Subjects: formation [Astrochemistry – stars], FOS: Physical sciences, Nanotechnology, 01 natural sciences, 0103 physical sciences, Protostar, 010303 astronomy & astrophysics, Astrochemistry, Stars: formation-ISM: jets and outflows-ISM: molecules, molecules [ISM], ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, jets and outflows [ISM], Plateau de Bure Interferometer, Astronomy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, 3. Good health, ISM: jets and outflows, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrochemistry – stars: formation, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The shock L1157-B1 driven by the low-mass protostar L1157-mm is an unique environment to investigate the chemical enrichment due to molecules released from dust grains. IRAM-30m and Plateau de Bure Interferometer observations allow a census of Si-bearing molecules in L1157-B1. We detect SiO and its isotopologues and, for the first time in a shock, SiS. The strong gradient of the [SiO/SiS] abundance ratio across the shock (from >=180 to ~25) points to a different chemical origin of the two species. SiO peaks where the jet impacts the cavity walls ([SiO/H2] ~ 1e-6), indicating that SiO is directly released from grains or rapidly formed from released Si in the strong shock occurring at this location. In contrast, SiS is only detected at the head of the cavity opened by previous ejection events ([SiS/H2] ~ 2e-8). This suggests that SiS is not directly released from the grain cores but instead should be formed through slow gas-phase processes using part of the released silicon. This finding shows that Si-bearing molecules can be useful to distinguish regions where grains or gas-phase chemistry dominates., 5 pages, 4 figure, 1 page of appendices
Published: 2017

14. Nature of shocks revealed by SOFIA OI observations in the Cepheus E protostellar outflow

Author: Bertrand Lefloch, Helmut Wiesemeyer, Rolf Guesten, K. Jacobs, S. Leurini, C. Codella, Benjamin Godard, Lars E. Kristensen, Antoine Gusdorf, A. I. Gómez-Ruiz, P. Lesaffre, S. Anderl, Dariusz C. Lis, G. Pineau des Forêts, M. Benedettini, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], California Institute of Technology (CALTECH), ITA, USA, FRA, DEU, DNK, MEX, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Universiteit Leiden, and École normale supérieure - Paris (ENS Paris)
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, 01 natural sciences, 0103 physical sciences, Protostar, ISM: individual objects: Cepheus E, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation), Physics, infrared: ISM, ISM: kinematics and dynamics, Jet (fluid), stars: formation, Shock (fluid dynamics), astrochemistry, Astronomy and Astrophysics, Key features, Astrophysics - Astrophysics of Galaxies, Interstellar medium, Stars, ISM: jets and outflows, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Outflow, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Protostellar jets and outflows are key features of the star-formation process, and primary processes of the feedback of young stars on the interstellar medium. Understanding the underlying shocks is necessary to explain how jets and outflows are launched, and to quantify their chemical and energetic impacts on the surrounding medium. We performed a high-spectral resolution study of the [OI]$_{\rm 63 \mu m}$ emission in the outflow of the intermediate-mass Class 0 protostar Cep E-mm. We present observations of the OI $^3$P$_1 \rightarrow$ $^3$P$_2$, OH between $^2\Pi_{1/2}$ $J = 3/2$ and $J = 1/2$ at 1837.8 GHz, and CO (16-15) lines with SOFIA-GREAT at three positions in the Cep E outflow: mm (the driving protostar), BI (in the southern lobe), and BII (the terminal position in the southern lobe). The CO line is detected at all three positions. The OI line is detected in BI and BII, whereas the OH line is not detected. In BII, we identify three kinematical components in OI and CO, already detected in CO: the jet, the HH377 terminal bow-shock, and the outflow cavity. The OI column density is higher in the outflow cavity than in the jet, which itself is higher than in the terminal shock. The terminal shock is where the abundance ratio of OI to CO is the lowest (about 0.2), whereas the jet component is atomic (ratio $\sim$2.7). In the jet, we compare the OI observations with shock models that successfully fit the integrated intensity of 10 CO lines: these models do not fit the OI data. The high intensity of OI emission points towards the propagation of additional dissociative or alternative FUV-irradiated shocks, where the illumination comes from the shock itself. From the sample of low-to-high mass protostellar outflows where similar observations have been performed, the effects of illumination seem to increase with the mass of the protostar., Comment: 9 pages, 4 figures, 6 tables, Astronomy and astrophysics, in press
Published: 2017

15. The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71$_.^circ$0 < ℓ < 67$_.^circ$0)

Author: Takahiro Hayakawa, David Eden, Melvin Hoare, Francesco Strafella, F. Piacentini, Kenneth A. Marsh, Sergio Molinari, S. E. Jaffa, Pedro García-Lario, Alessio Traficante, Peter Schilke, Kengo Tachihara, G. Joncas, J.-P. Bernard, M. R. Pestalozzi, S. Martinavarro-Armengol, Amata Mercurio, Alessandro Costa, Friedrich Wyrowski, Eva Sciacca, Robert Butora, B. Maiolo, Joseph C. Mottram, Mark Thompson, D. Polychroni, H. Yamamoto, G. Li Causi, P. Palmeirim, M. Benedettini, D. Russeil, Hidetoshi Sano, Kazi L.J. Rygl, Eugenio Schisano, Stefano Cavuoti, Annie Zavagno, Sarah Ragan, John Bally, M. Veneziani, Carla Buemi, A. P. Whitworth, K. Torii, Massimo Brescia, Péter Kacsuk, Davide Elia, Marco Molinaro, Nicola Schneider, Ugo Becciani, Rene Plume, Göran Pilbratt, A. M. di Giorgio, F. Faustini, P. Mège, Luca Calzoletti, Grazia Umana, Stefano Pezzuto, H. Arab, E. Fiorellino, Derek Ward-Thompson, S. J. Liu, Marilena Bandieramonte, M. T. Beltrán, Paolo Leto, Y. Maruccia, Roberta Paladini, Toby J. T. Moore, Giuseppe Riccio, Fabio Vitello, Luca Olmi, N. Marchili, Frédérique Motte, Corrado Trigilio, Ákos Hajnal, Yasuo Fukui, Nicolas Peretto, Alberto Noriega-Crespo, A. Baldeschi, Riccardo Cesaroni, Leonardo Testi, Lorenzo Piazzo, Manuel Merello, L. Cambrésy, Filomena Bufano, Peter G. Martin, Nicolas Billot, Meng-Lin Huang, Paolo Natoli, Elia, D., Molinari, S., Schisano, E., Pestalozzi, M., Pezzuto, Marilena, Merello, M., Noriega-Crespo, A., Moore, T. J. T., Russeil, D., Mottram, J. C., Paladini, R., Strafella, F., Benedettini, M., Bernard, J. P., Di Giorgio, A., Eden, D. J., Fukui, Y., Plume, R., Bally, J., Martin, P. G., Ragan, S. E., Jaffa, S. E., Motte, F., Olmi, L., Schneider, N., Testi, L., Wyrowski, F., Zavagno, A., Calzoletti, L., Faustini, F., Natoli, P., Palmeirim, P., Piacentini, F., Piazzo, L., Pilbratt, G. L., Polychroni, D., Baldeschi, A., Beltrán, M. T., Billot, N., Cambrésy, L., Cesaroni, R., García-Lario, P., Hoare, M. G., Huang, M., Joncas, G., Liu, S. J., Maiolo, B. M. T., Marsh, K. A., Maruccia, Y., Mège, P., Peretto, N., Rygl, K. L. J., Schilke, P., Thompson, M. A., Traficante, A., Umana, G., Veneziani, M., Ward-Thompson, D., Whitworth, A. P., Arab, H., Bandieramonte, M., Becciani, U., Brescia, M., Buemi, C., Bufano, F., Butora, R., Cavuoti, S., Costa, A., Fiorellino, E., Hajnal, A., Hayakawa, T., Kacsuk, P., Leto, P., Li Causi, G., Marchili, N., Martinavarro-Armengol, S., Mercurio, A., Molinaro, M., Riccio, G., Sano, H., Sciacca, E., Tachihara, K., Torii, K., Trigilio, C., Vitello, F., Yamamoto, H., Elia, Davide, Pezzuto, S., Noriega Crespo, A., Strafella, Francesco, García Lario, P., Maiolo, BERLINDA MARIA TERESA, Maruccia, Ylenia, Ward Thompson, D., and Martinavarro Armengol, S.
Subjects: Astrophysics and Astronomy, Infrared, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, cataloghi astronomici, mezzo interstellare, osservazioni infrarosse, osservazioni submillimetriche, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, QC, QB, Physics, Spiral galaxy, 010308 nuclear & particles physics, Star formation, Spectral density, Astronomy, Astronomy and Astrophysics, Galactic plane, Galaxy, Stars, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, catalogues, ISM clouds, dust, extinction, local interstellar matter, infrared ISM, submillimetre ISM, Longitude
Abstract: Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 μm. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane −71 ∘. 0 < ℓ < 67 ∘. 0. The band-merged catalogue contains 100 922 sources with a regular SED, 24 584 of which show a 70-μm counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between ‘on-arm’ and ‘interarm’ positions. Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 $\mu$m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogs presented in Molinari et al. (2016a), covering the portion of Galactic plane $-71.0^{\circ}< \ell < 67.0^{\circ}$. The band-merged catalogue contains 100922 sources with a regular SED, 24584 of which show a 70 $\mu$m counterpart and are thus considered proto-stellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterise different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in proto-stellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to proto-stellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between "on-arm" and "inter-arm" positions.
Published: 2017

16. Distance biases in the estimation of the physical properties of Hi-GAL compact sources-I. Clump properties and the identification of high-mass star forming candidates

Author: J. S. Liu, Eugenio Schisano, M. Benedettini, Davide Elia, Stefano Pezzuto, Adriano Baldeschi, Manuel Merello, Sergio Molinari, M. Gatti, A. M. di Giorgio, and A. Serra
Subjects: Star (game theory), Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Position (vector), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Image resolution, Astrophysics::Galaxy Astrophysics, Physics, education.field_of_study, 010308 nuclear & particles physics, Diagram, Astronomy, Astronomy and Astrophysics, Radius, Astrophysics - Astrophysics of Galaxies, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Methods: statistical, stars: formation, ISM: clouds, infrared: ISM, Astrophysics::Earth and Planetary Astrophysics, Resolution (algebra)
Abstract: The degradation of spatial resolution in star-forming regions observed at large distances ($d\gtrsim1$ kpc) with Herschel,can lead to estimates of the physical parameters of the detected compact sources (clumps) which do not necessarily mirror the properties of the original population of cores. This paper aims at quantifying the bias introduced in the estimation of these parameters by the distance effect. To do so, we consider Herschel maps of nearby star-forming regions taken from the Herschel-Gould-Belt survey, and simulate the effect of increased distance to understand what amount of information is lost when a distant star-forming region is observed with Herschel resolution. In the maps displaced to different distances we extract compact sources, and we derive their physical parameters as if they were original Hi-GAL maps of the extracted source samples. In this way, we are able to discuss how the main physical properties change with distance. In particular, we discuss the ability of clumps to form massive stars: we estimate the fraction of distant sources that are classified as high-mass stars-forming objects due to their position in the mass vs radius diagram, that are only "false positives". We give also a threshold for high-mass star-formation $M>1282 \ \left(\frac{r}{[\mathrm{pc}]}\right)^{1.42} M_{\odot}$. In conclusion, this paper provides the astronomer dealing with Herschel maps of distant star-forming regions with a set of prescriptions to partially recover the character of the core population in unresolved clumps., 32 pages, 42 figures, accepted for publication in MNRAS
Published: 2017
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17. The earliest phases of high-mass star formation, as seen in NGC 6334 by Herschel-HOBYS

Author: Pierre Didelon, L. D. Anderson, Sergio Molinari, Doris Arzoumanian, Stefano Pezzuto, Nicola Schneider, Jason M. Kirk, Q. Nguyen Luong, Vincent Minier, G. Leuleu, J. Di Francesco, F. Louvet, Pierrick Martin, M. Benedettini, K. L. J. Rygl, Annie Zavagno, D. Russeil, T. Rayner, J. Bardagi, D. Polychroni, T. Nony, Ph. André, M. Figueira, Tracey Hill, J.-P. Bernard, P. Persi, Davide Elia, Vera Konyves, A. Rivera-Ingraham, G. J. White, H. Roussel, Luigi Spinoglio, J. Tigé, Sylvain Bontemps, M. Hennemann, Frédérique Motte, Sciences pour l'environnement (SPE), Université Pascal Paoli (UPP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), FORMATION STELLAIRE 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Centro de Matemática e Aplicações Fundamentais (CMAF), Universidade de Lisboa = University of Lisbon (ULISBOA), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Faculty of Informatics [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), School of Physics and Astronomy [Cardiff], Cardiff University, Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Antarctic Research a European Network for Astrophysics (ARENA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Engineering Department, University of Cambridge [UK] (CAM), Centre National de la Recherche Scientifique (CNRS)-Université Pascal Paoli (UPP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidade de Lisboa (ULISBOA), Consiglio Nazionale delle Ricerche (CNR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), ITA, GBR, FRA, and CAN
Subjects: Physics, stars: formation, 010504 meteorology & atmospheric sciences, stars: protostars, Star formation, extinction, Molecular cloud, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, ISM: clouds, Spire, ISM: individual objects: NGC 6334, Space and Planetary Science, 0103 physical sciences, High mass, Protostar, submillimeter: ISM, Millimeter, dust, extinction, dust, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Aims: To constrain models of high-mass star formation, the Herschel-HOBYS key program aims at discovering massive dense cores (MDCs) able to host the high-mass analogs of low-mass prestellar cores, which have been searched for over the past decade. We here focus on NGC 6334, one of the best-studied HOBYS molecular cloud complexes. Methods: We used Herschel/PACS and SPIRE 70-500 μm images of the NGC 6334 complex complemented with (sub)millimeter and mid-infrared data. We built a complete procedure to extract 0.1 pc dense cores with the getsources software, which simultaneously measures their far-infrared to millimeter fluxes. We carefully estimated the temperatures and masses of these dense cores from their spectral energy distributions (SEDs). We also identified the densest pc-scale cloud structures of NGC 6334, one 2 pc × 1 pc ridge and two 0.8 pc × 0.8 pc hubs, with volume-averaged densities of 105 cm-3. Results: A cross-correlation with high-mass star formation signposts suggests a mass threshold of 75 M☉ for MDCs in NGC 6334. MDCs have temperatures of 9.5-40 K, masses of 75-1000 M☉, and densities of 1 × 105-7 × 107 cm-3. Their mid-infrared emission is used to separate 6 IR-bright and 10 IR-quiet protostellar MDCs while their 70 μm emission strength, with respect to fitted SEDs, helps identify 16 starless MDC candidates. The ability of the latter to host high-mass prestellar cores is investigated here and remains questionable. An increase in mass and density from the starless to the IR-quiet and IR-bright phases suggests that the protostars and MDCs simultaneously grow in mass. The statistical lifetimes of the high-mass prestellar and protostellar core phases, estimated to be 1-7 × 104 yr and at most 3 × 105 yr respectively, suggest a dynamical scenario of high-mass star formation. Conclusions: The present study provides good mass estimates for a statistically significant sample, covering the earliest phases of high-mass star formation. High-mass prestellar cores may not exist in NGC 6334, favoring a scenario presented here, which simultaneously forms clouds, ridges, MDCs, and high-mass protostars. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. Catalogs built from Tables A.1-A.12, are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A77
Published: 2017

18. Sulfur Chemistry in L1157-B1

Author: M. Benedettini, Izaskun Jiménez-Serra, C. Codella, Linda Podio, Jonathan Holdship, Cecilia Ceccarelli, Francesco Fontani, Rafael Bachiller, Serena Viti, and Mario Tafalla
Subjects: Shock wave, Range (particle radiation), COSMIC cancer database, Chemistry, FOS: Physical sciences, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Sulfur, Gas phase, 010309 optics, 13. Climate action, Space and Planetary Science, Abundance (ecology), Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Isotopologue, Outflow, 010303 astronomy & astrophysics
Abstract: The main carrier of sulfur in dense clouds, where it is depleted from the gas phase, remains a mystery. Shock waves in young molecular outflows disrupt the ice mantles and allow us to directly probe the material that is ejected into the gas phase. A comprehensive study of sulfur-bearing species towards L1157-B1, a shocked region along a protostellar outflow, has been carried out as part of the IRAM-30m large program ASAI. The dataset contains over 100 lines of CCS, H$_2$CS, OCS, SO, SO$_2$ and isotopologues. The results of these observations are presented, complementing previous studies of sulfur-bearing species in the region. The column densities and fractional abundances of these species are measured and together these species account for 10\% of the cosmic sulfur abundance in the region. The gas properties derived from the observations are also presented, demonstrating that sulfur bearing species trace a wide range of different gas conditions in the region., Comment: Accepted for publication in ApJ
Published: 2019

19. H2S in the L1157-B1 Bow shock

Author: Linda Podio, Izaskun Jiménez-Serra, Claudio Codella, Mario Tafalla, Serena Viti, Cecilia Ceccarelli, Francesco Fontani, Bertrand Lefloch, M. Benedettini, Rafael Bachiller, and Jonathan Holdship
Subjects: Physics, 010308 nuclear & particles physics, chemistry.chemical_element, Astronomy and Astrophysics, Bow shocks in astrophysics, Branching (polymer chemistry), 01 natural sciences, Molecular physics, Sulfur, Astrophysics - Astrophysics of Galaxies, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Protostar, Molecule, Isotopologue, Low Mass, 010303 astronomy & astrophysics, Cosmic dust
Abstract: Sulfur-bearing molecules are highly reactive in the gas phase of the ISM. However, the form in which most of the sulfur is locked onto interstellar dust grains is unknown. By taking advantage of the short time-scales of shocks in young molecular outflows, one could track back the main form of sulfur in the ices. In this paper, six transitions of H$_2$S and its isotopologues in the L1157-B1 bowshock have been detected using data from the Herschel-CHESS survey and the IRAM-30m ASAI large program. These detections are used to calculate the properties of H$_2$S gas in L1157-B1 through use of a rotation diagram and to explore the possible carriers of sulfur on the grains. The isotopologue detections allow the first calculation of the H$_2$S deuteration fraction in an outflow from a low mass protostar. The fractional abundance of H$_2$S in the region is found to be 6.0$\times$10$^{-7}$ and the deuteration fraction is 2$\times$10$^{-2}$. In order to investigate the form of sulfur on the grains, a chemical model is run with four different networks, each with different branching ratios for the freeze out of sulfur bearing species into molecules such as OCS and H$_2$S. It is found that the model best fits the data when at least half of each sulfur bearing species hydrogenates when freezing. We therefore conclude that a significant fraction of sulfur in L1157-B1 is likely to be locked in H$_2$S on the grains., Comment: 10 Pages, 7 Figures. Accepted for publication in MNRAS
Published: 2016

20. Hi-GAL, the Herschel infrared Galactic Plane Survey: Photometric maps and compact source catalogues: First data release for the inner Milky Way: +68° ≥ l ≥ -70°

Author: Stefano Pezzuto, Annie Zavagno, M. J. Barlow, Nicolas Peretto, S. D. Lord, Yasuo Fukui, Davide Elia, G. Polenta, D. Russeil, Sergio Molinari, Thomas P. Robitaille, R. Del Grande, G. Umana, Riccardo Cesaroni, M. Benedettini, Pascal André, Benjamin L. Schulz, Babar Ali, Pierrick Martin, David Eden, P. Natoli, Göran Pilbratt, Manuel Merello, R. Paladini, Francesco Strafella, Alessio Traficante, Luca Calzoletti, Mathieu Compiegne, Derek Ward-Thompson, Peter Schilke, Gilles Joncas, Rene Plume, Nicola Schneider, Pedro García-Lario, J.-P. Bernard, Kazi L.J. Rygl, Leonardo Testi, M. T. Beltrán, M. R. Pestalozzi, F. Piacentini, A. M. di Giorgio, Eugenio Schisano, Christopher M. Brunt, John Bally, N. Billot, Maggie A. Thompson, Sean K. Carey, Joseph C. Mottram, B. M. Swinyard, Melvin Hoare, F. Faustini, S. J. Liu, S. Martinavarro-Armengol, D. Paradis, Toby J. T. Moore, D. Polychroni, Antonella Palmese, Friedrich Wyrowski, Alberto Noriega-Crespo, Lorenzo Piazzo, Tanya Lim, M. Veneziani, Meng-Lin Huang, Bruce Sibthorpe, and Frédérique Motte
Subjects: Physics, Line-of-sight, 010308 nuclear & particles physics, Infrared, Milky Way, Bolometer, Astronomy and Astrophysics, Astrophysics, Galactic plane, dust, extinction, Galaxy: disk, infrared: ISM, methods: data analysis, stars: formation, techniques: photometric, astronomy and astrophysics, space and planetary science, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, law.invention, symbols.namesake, Wavelength, 13. Climate action, Space and Planetary Science, law, 0103 physical sciences, symbols, Spectral energy distribution, Planck, 010303 astronomy & astrophysics, QC, QB
Abstract: (Abridged) We present the first public release of high-quality data products (DR1) from Hi-GAL, the {\em Herschel} infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic Plane surveys from the near-IR to the radio, and covers five wavebands at 70, 160, 250, 350 and 500 micron, encompassing the peak of the spectral energy distribution of cold dust for 8 < T < 50K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68{\deg} > l > -70{\deg} in a |b, Comment: Astronomy & Astrophysics, accepted
Published: 2016

21. A census of dense cores in the Taurus L1495 cloud from the Herschel Gould Belt Survey

Author: Glenn J. White, Ph. André, Stefano Pezzuto, Alexander Men'shchikov, P. Palmeirim, M. Benedettini, Matthew Joseph Griffin, D. Bresnahan, J. Di Francesco, A. Roy, Sarah Sadavoy, Kenneth A. Marsh, Davide Elia, Nicola Schneider, Luigi Spinoglio, Jason M. Kirk, Derek Ward-Thompson, Nicolas Peretto, Frédérique Motte, Vera Könyves, University of California [Los Angeles] (UCLA), University of California (UC), Jeremiah Horrocks Insitute, University of Central Lancashire [Preston] (UCLAN), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of Physics and Astronomy [Cardiff], Cardiff University, Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Department of Physics and Astronomy [Victoria], University of Victoria [Canada] (UVIC), Faculty of Informatics [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), Laboratoire Pierre Aigrain (LPA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), University Hospital of Cologne [Cologne], FORMATION STELLAIRE 2016, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), SLAC National Accelerator Laboratory (SLAC), Stanford University, University of California, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Università della Svizzera italiana (USI), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Stanford Linear Accelerator Center (SLAC), and Stanford University [Stanford]
Subjects: Initial mass function, FOS: Physical sciences, F500, Astrophysics, 01 natural sciences, Volume density, Stars formation, submillimetre, L1495, 0103 physical sciences, ISM individual objects, Black-body radiation, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], local interstellar matter, 010308 nuclear & particles physics, Turbulence, Luminosity function, Astronomy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM clouds, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Mass function, Astrophysics of Galaxies (astro-ph.GA), Log-normal distribution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We present a catalogue of dense cores in a $\sim 4^\circ\times2^\circ$ field of the Taurus star-forming region, inclusive of the L1495 cloud, derived from Herschel SPIRE and PACS observations in the 70 $\mu$m, 160 $\mu$m, 250 $\mu$m, 350 $\mu$m, and 500 $\mu$m continuum bands. Estimates of mean dust temperature and total mass are derived using modified blackbody fits to the spectral energy distributions. We detect 525 starless cores of which $\sim10$-20% are gravitationally bound and therefore presumably prestellar. Our census of unbound objects is $\sim85$% complete for $M>0.015\,M_\odot$ in low density regions ($A_V\stackrel{0.1\,M_\odot$ overall. The prestellar core mass function (CMF) is consistent with lognormal form, resembling the stellar system initial mass function, as has been reported previously. All of the inferred prestellar cores lie on filamentary structures whose column densities exceed the expected threshold for filamentary collapse, in agreement with previous reports. Unlike the prestellar CMF, the unbound starless CMF is not lognormal, but instead is consistent with a power-law form below $0.3\,M_\odot$ and shows no evidence for a low-mass turnover. It resembles previously reported mass distributions for CO clumps at low masses ($M\stackrel{, Comment: 17 pages, 12 figures. Accepted for publication in MNRAS
Published: 2016

22. Large-scale latitude distortions of the inner Milky Way disk from the Herschel/Hi-GAL Survey

Author: Stefano Pezzuto, Leonardo Testi, Rene Plume, Davide Elia, John Bally, Sergio Molinari, Anna Maria Di Giorgio, M. Benedettini, Bruce Swinyard, Alberto Noriega-Crespo, Toby J. T. Moore, and Eugenio Schisano
Subjects: Milky Way, FOS: Physical sciences, 02 engineering and technology, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Latitude, Gravitation, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, QB, Physics, Number density, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Interstellar medium, Stars, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 020201 artificial intelligence & image processing, Astrophysics::Earth and Planetary Astrophysics, Longitude
Abstract: We use the Herschel Hi-GAL survey data to study the spatial distribution in Galactic longitude and latitude of the interstellar medium and of dense, star-forming clumps in the inner Galaxy. The peak position and width of the latitude distribution of the dust column density as well as of number density of compact sources from the band-merged Hi-GAL photometric catalogues are analysed as a function of longitude. The width of the diffuse dust column density traced by the Hi-GAL 500 micron emission varies across the inner Galaxy, with a mean value of 1{\deg}.2-1{\deg}.3, similar to that of the 250um Hi-GAL sources. 70um Hi-GAL sources define a much thinner disk, with a mean FWHM of 0{\deg}.75, and an average latitude of b=0{\deg}.06, coincident with the results from ATLASGAL. The GLAT distribution as a function of GLON shows modulations, both for the diffuse emission and for the compact sources, with ~0{\deg}.2 displacements mostly toward negative latitudes at l~ +40{\deg}, +12{\deg}, -25{\deg} and -40{\deg}. No such modulations can be found in the MIPSGAL 24 or WISE 22 um data when the entire source samples are considered. The distortions revealed by Herschel are interpreted as large-scale bending modes of the Plane. The lack of similar distortions in tracers of more evolved YSOs or stars rules out gravitational instabilities or satellite-induced perturbations, as they should act on both the diffuse and stellar disk components. We propose that the observed bends are caused by incoming flows of extra-planar gas interacting with the gaseous disk. Stars decouple from the gaseous ISM and relax into the stellar disk potential. The time required for the disappearance of the distortions from the diffuse ISM to the relatively evolved YSO stages are compatible with star-formation timescales., Comment: Astronomy & Astrophysics, accepted. 13 pages, 9 figures
Published: 2016

23. From forced collapse to H ii region expansion in Mon R2: Envelope density structure and age determination with Herschel

Author: Frédérique Motte, D. Ward-Thompson, Annie Zavagno, D. Russeil, Marc Sauvage, Pierre Didelon, M. Hennemann, J. Di Francesco, Thomas Rayner, L. D. Anderson, A. Rivera-Ingraham, F. Louvet, Glenn J. White, Doris Arzoumanian, Sacha Hony, Alexander Men'shchikov, Ph. André, Frédéric Galliano, Nicolas Peretto, J.-P. Bernard, Tracey Hill, Pascal Tremblin, Vianney Lebouteiller, Vera Könyves, P. Palmeirim, Q. Nguyen Luong, M. Benedettini, K. L. J. Rygl, Stefano Pezzuto, Vincent Minier, M. González, Patrick Hennebelle, Matthew James Griffin, Sylvain Bontemps, Nicola Schneider, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Exeter, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Joint ALMA Office, Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, National Radio Astronomy Observatory (NRAO), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Physics and Astronomy [Cardiff], Cardiff University, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), National Research Council of Canada (NRC), Institut de recherche en astrophysique et planétologie (IRAP), Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), ANR-08-BLAN-0241,PROBES,Etoiles Proto-OB : recherche systématique dans notre Galaxie des cibles pour ALMA(2008), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Ionization, H II region, ISM: individual objects: Mon R2, Numerical models, ISM: structure, Extinction (astronomy), FOS: Physical sciences, Collapse (topology), F500, Astrophysics, Isothermal process, Stars: protostars, Clouds, Quenching, H II regions, Solar and Stellar Astrophysics (astro-ph.SR), Envelope (waves), QB, Physics, Dust , extinction, Molecular cloud, Astronomy and Astrophysics, Stars, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Density of gases
Abstract: The surroundings of HII regions can have a profound influence on their development, morphology, and evolution. This paper explores the effect of the environment on H II regions in the MonR2 molecular cloud. We aim to investigate the density structure of envelopes surrounding HII regions and to determine their collapse and ionisation expansion ages. The Mon R2 molecular cloud is an ideal target since it hosts an H II region association. Column density and temperature images derived from Herschel data were used together to model the structure of HII bubbles and their surrounding envelopes. The resulting observational constraints were used to follow the development of the Mon R2 ionised regions with analytical calculations and numerical simulations. The four hot bubbles associated with H II regions are surrounded by dense, cold, and neutral gas envelopes. The radial density profiles are reminiscent of those of low-mass protostellar envelopes. The inner parts of envelopes of all four HII regions could be free-falling because they display shallow density profiles. As for their outer parts, the two compact HII regions show a density profile, which is typical of the equilibrium structure of an isothermal sphere. In contrast, the central UCHii region shows a steeper outer profile, that could be interpreted as material being forced to collapse. The size of the heated bubbles, the spectral type of the irradiating stars, and the mean initial neutral gas density are used to estimate the ionisation expansion time, texp, 0.1Myr,for the dense UCHII and compact HII regions and 0.35 Myr for the extended HII region. The envelope transition radii between the shallow and steeper density profiles are used to estimate the time elapsed since the formation of the first proto stellar embryo, Tinf : 1Myr, for the ultra-compact, 1.5 / 3Myr for the compact, and greater than 6Myr for the extended HII regions., 25pages A&A sous presse
Published: 2015

24. Multiline spectral imaging of dense cores in the Lupus molecular cloud

Author: Stefano Pezzuto, Michael G. Burton, Sergio Molinari, Serena Viti, M. Benedettini, Leonardo Testi, and Paola Caselli
Subjects: Physics, education.field_of_study, Star formation, Molecular cloud, Young stellar object, Population, Lupus (constellation), Astronomy and Astrophysics, Astrophysics, Stars, Space and Planetary Science, Protostar, Emission spectrum, education
Abstract: The molecular clouds Lupus 1, 3 and 4 were mapped with the Mopra Telescope at 3 and 12 mm. Emission lines from high-density molecular tracers were detected, i.e. NH3 (1,1), NH3 (2,2), N2H+ (1−0), HC3N (3−2), HC3N (10−9), CS (2−1), CH3OH (20−10)A+ and CH3OH (2−1−1−1)E. Velocity gradients of more than 1 km s−1 are present in Lupus 1 and 3, and multiple gas components are present in these clouds along some lines of sight. Lupus 1 is the cloud richest in high-density cores: eight cores were detected in it, five cores were detected in Lupus 3 and only two in Lupus 4. The intensity of the three species HC3N, NH3 and N2H+ changes significantly in the various cores: cores that are brighter in HC3N are fainter or undetected in NH3 and N2H+ and vice versa. We found that the column density ratios HC3N/N2H+ and HC3N/NH3 change by 1 order of magnitude between the cores, indicating that also the chemical abundance of these species is different. The time-dependent chemical code that we used to model our cores shows that the HC3N/N2H+ and HC3N/NH3 ratios decrease with time, therefore the observed column density of these species can be used as an indicator of the chemical evolution of dense cores. On this basis we classified five out of eight cores in Lupus 1 and one out of five cores in Lupus 3 as very young protostars or pre-stellar cores. Comparing the millimetre core population with the population of the more evolved young stellar objects identified in the Spitzer surveys, we conclude that in Lupus 3 the bulk of the star formation activity has already passed and only a moderate number of stars are still forming. In contrast, in Lupus 1 star formation is ongoing and several dense cores are still in the pre-/protostellar phase. Lupus 4 is at an intermediate stage, with a smaller number of individual objects.
Published: 2011

25. Methyl cyanide as tracer of bow shocks in L1157-B1

Author: Serena Viti, M. T. Beltrán, Bertrand Lefloch, Claudio Codella, Mario Tafalla, Rafael Bachiller, M. Benedettini, Frédéric Gueth, Asunción Fuente, Sylvie Cabrit, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Shock wave, Physics, 010504 meteorology & atmospheric sciences, Star formation, Plateau de Bure Interferometer, Astronomy and Astrophysics, Context (language use), Astrophysics, 01 natural sciences, Shock (mechanics), [SDU]Sciences of the Universe [physics], Space and Planetary Science, 0103 physical sciences, Protostar, Outflow, Bow shock (aerodynamics), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; Context: L1157-mm is a low-mass protostar driving an outflow which is considered the proto-type of the so-called chemically active outflows. In particular, the blue-shifted lobe B1 stands out for its rich mm-wave spectrum. Aims: Our aim is to infer the physical conditions of the molecular gas within L1157-B1. Methods: We carried out CH3CN(8{K}-7{K}) observations at 2 mm with the IRAM Plateau de Bure Interferometer to map L1157-B1. Results: The CH3CN image shows a clumpy structure superimposed to the classical B1 arch-like shape, displaying a unique continuous structure tracing the propagation of a large bow shock. The CH3CN spatial distribution well agrees with that of CH3OH, one of the most abundant species evaporated from dust grain mantles. Thanks to the present CH3CN observations at unprecedented spatial resolution, we determine for the first time the temperature distribution of the B1 bow shock. We obtain values between 57 and 132 K, with the highest temperature at the shock apex, thus confirming the association of CH3CN with gas affected by the passage of a shock wave. The N_CH_3CN column densities are ≃8-40 × 1012 cm-2, depending on the position, leading to CH3CN/CH3OH abundance ratios ≃0.2-1.3 × 10-3, i.e. values on average smaller than those found in hot-corinos. This suggests that a significant amount of CH3CN is formed in the gas phase: in the shocked L1157-B1 regions the CH3CN abundance may not have reached its maximum yet.
Published: 2009

26. Filaments in the Lupus molecular clouds

Author: Stefano Pezzuto, Davide Elia, Nicola Schneider, Sergio Molinari, Kazi L.J. Rygl, P. Palmeirim, A. M. di Giorgio, Luigi Spinoglio, J. Di Francesco, Glenn J. White, Ph. André, Derek Ward-Thompson, A. Roy, Vera Könyves, Frédérique Motte, A. Rivera-Ingraham, Pascal Tremblin, Eugenio Schisano, Quang Nguyen-Luong, Doris Arzoumanian, M. Benedettini, Tracey Hill, FORMATION STELLAIRE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Exeter, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), foreign laboratories (FL), CERN [Genève], INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Procédés, Matériaux et Energie Solaire (PROMES), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Unité expérimentale de Pech-Rouge (PECH ROUGE), Institut National de la Recherche Agronomique (INRA), SLAC National Accelerator Laboratory (SLAC), Stanford University, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of Victoria [Canada] (UVIC), National Research Council of Canada (NRC), National Astronomical Observatory of Japan (NAOJ), Canadian Institute for Theoretical Astrophysics (CITA), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Bologna (OABO), Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), The Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, The Open University [Milton Keynes] (OU), ANR-11-BS56-0010,STARFICH,Vers une vision unifiée de la formation stellaire dans les galaxies : Origine de la structure filamentaire du milieu interstellaire, des cœurs pré-stellaires et des amas protostellaires vus avec Herschel(2011), European Project: 291294,EC:FP7:ERC,ERC-2011-ADG_20110209,ORISTARS(2012), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Unité d'oenologie de Pech-Rouge (MONTP PECH ROUG UE), Stanford Linear Accelerator Center (SLAC), and Stanford University [Stanford]
Subjects: Physics, stars: formation, Star formation, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Molecular cloud, Lupus (constellation), Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, F500, Critical value, Astrophysics - Astrophysics of Galaxies, ISM: clouds, Magnetic field, Protein filament, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Gravitational collapse, Astrophysics::Earth and Planetary Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract: We have studied the filaments extracted from the column density maps of the nearby Lupus 1, 3, and 4 molecular clouds, derived from photometric maps observed with the Herschel satellite. Filaments in the Lupus clouds have quite low column densities, with a median value of $\sim$1.5$\times$10$^{21}$ cm$^{-2}$ and most have masses per unit length lower than the maximum critical value for radial gravitational collapse. Indeed, no evidence of filament contraction has been seen in the gas kinematics. We find that some filaments, that on average are thermally subcritical, contain dense cores that may eventually form stars. This is an indication that in the low column density regime, the critical condition for the formation of stars may be reached only locally and this condition is not a global property of the filament. Finally, in Lupus we find multiple observational evidences of the key role that the magnetic field plays in forming filaments, and determining their confinement and dynamical evolution., Comment: 16 pages, 16 figures
Published: 2015

27. The structure of the Cepheus E protostellar outflow: The jet, the bowshock, and the cavity

Author: Rolf Güsten, Antoine Gusdorf, Arturo I. Gómez-Ruiz, Claudio Codella, R. Neri, M. Benedettini, J. Eislöffel, Silvia Leurini, Christophe Risacher, Bertrand Lefloch, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Thüringer Landessternwarte Tautenburg (TLS), Division for Submm Technologies, Max-Planck-Institut für Radioastronomie (MPIFR), ESO, European Southern Observatory (ESO), and École normale supérieure - Paris (ENS-PSL)
Subjects: Shock wave, Physics, Jet (fluid), Plateau de Bure Interferometer, Astronomy and Astrophysics, Context (language use), Astrophysics, 13. Climate action, Space and Planetary Science, Protostar, Outflow, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Spectral resolution, James Clerk Maxwell Telescope, ComputingMilieux_MISCELLANEOUS
Abstract: Context. Protostellar outflows are a crucial ingredient of the star-formation process. However, the physical conditions in the warm outflowing gas are still poorly known. Aims: We present a multi-transition, high spectral resolution CO study of the outflow of the intermediate-mass Class 0 protostar Cep E-mm. The goal is to determine the structure of the outflow and to constrain the physical conditions of the various components in order to understand the origin of the mass-loss phenomenon. Methods: We have observed the J = 12-11, J = 13-12, and J = 16-15 CO lines at high spectral resolution with SOFIA/GREAT and the J = 5-4, J = 9-8, and J = 14-13 CO lines with HIFI/Herschel towards the position of the terminal bowshock HH377 in the southern outflow lobe. These observations were complemented with maps of CO transitions obtained with the IRAM 30 m telescope (J = 1-0, 2-1), the Plateau de Bure interferometer (J = 2-1), and the James Clerk Maxwell Telescope (J = 3-2, 4-3). Results: We identify three main components in the protostellar outflow: the jet, the cavity, and the bowshock, with a typical size of 1.7″ × 21″, 4.5″, and 22″ × 10″, respectively. In the jet, the emission from the low-J CO lines is dominated by a gas layer at Tkin = 80-100 K, column density N(CO) = 9 × 1016 cm-2, and density n(H2) = (0.5-1) × 105 cm-3; the emission of the high-J CO lines arises from a warmer (Tkin = 400-750 K), denser (n(H2) = (0.5-1) × 106 cm-3), lower column density (N(CO) = 1.5 × 1016 cm-2) gas component. Similarly, in the outflow cavity, two components are detected: the emission of the low-J lines is dominated by a gas layer of column density N(CO) = 7 × 1017 cm-2 at Tkin = 55-85 K and density in the range (1-8) × 105 cm-3; the emission of the high-J lines is dominated by a hot, denser gas layer with Tkin = 500-1500K, n(H2) = (1-5) × 106 cm-3, and N(CO) = 6 × 1016 cm-2. A temperature gradient as a function of the velocity is found in the high-excitation gas component. In the terminal bowshock HH377, we detect gas of moderate excitation, with a temperature in the range Tkin ≈ 400-500 K, density n(H2) ≃ (1 -2) × 106 cm-3 and column density N(CO) = 1017 cm-2. The amounts of momentum carried away in the jet and in the entrained ambient medium are similar. Comparison with time-dependent shock models shows that the hot gas emission in the jet is well accounted for by a magnetized shock with an age of 220-740 yr propagating at 20-30 km s-1 in a medium of density n(H2) = (0.5-1) × 105 cm-3, consistent with that of the bulk material. Conclusions: The Cep E protostellar outflow appears to be a convincing case of jet bowshock driven outflow. Our observations trace the recent impact of the protostellar jet into the ambient cloud, produing a non-stationary magnetized shock, which drives the formation of an outflow cavity. Appendices are available in electronic form at http://www.aanda.org
Published: 2015

28. Detection of two power-law tails in the probability distribution functions of massive GMCs

Author: Nicola Schneider, D. Russeil, S. Pezzuto, Frédérique Motte, Volker Ossenkopf, L. Spinoglio, M. Benedettini, S. Bontemps, Timea Csengeri, T. Rayner, Alain Abergel, J. Di Francesco, P. Didelon, Philipp Girichidis, L. D. Anderson, A. Rivera-Ingraham, Ralf S. Klessen, Matthew Joseph Griffin, Pascal Tremblin, T. Hill, A. Zavagno, D. Arzoumanian, Ph. André, FORMATION STELLAIRE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, School of Physics and Astronomy [Cardiff], Cardiff University, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), National Radio Astronomy Observatory [Green Bank] (NRAO), National Radio Astronomy Observatory (NRAO), Department of Physics and Astronomy [Morgantown], West Virginia University [Morgantown], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Radioastronomie (MPIFR), NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg] = Heidelberg University, Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), University of Exeter, ANR-11-BS56-0010,STARFICH,Vers une vision unifiée de la formation stellaire dans les galaxies : Origine de la structure filamentaire du milieu interstellaire, des cœurs pré-stellaires et des amas protostellaires vus avec Herschel(2011), European Project: 291294,EC:FP7:ERC,ERC-2011-ADG_20110209,ORISTARS(2012), Laboratoire d'Astrophysique de Bordeaux [Pessac] ( LAB ), Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Procédés, Matériaux et Energie Solaire ( PROMES ), Université de Perpignan Via Domitia ( UPVD ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'astrophysique spatiale ( IAS ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), National Radio Astronomy Observatory [Green Bank] ( NRAO ), National Radio Astronomy Observatory ( NRAO ), School of Physics & Astronomy [Cardiff], Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Procédés, Matériaux et Energie Solaire (PROMES), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Physics, dust extinction, Angular momentum, extinction, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Extinction (astronomy), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Power law, Astrophysics - Astrophysics of Galaxies, ISM: clouds, Space and Planetary Science, [ SDU.ASTR.CO ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics of Galaxies (astro-ph.GA), Gravitational collapse, Log-normal distribution, Optical depth (astrophysics), Range (statistics), Probability distribution, clouds dust, ISM, Astrophysics::Galaxy Astrophysics
Abstract: We report the novel detection of complex high-column density tails in the probability distribution functions (PDFs) for three high-mass star-forming regions (CepOB3, MonR2, NGC6334), obtained from dust emission observed with Herschel. The low column density range can be fit with a lognormal distribution. A first power-law tail starts above an extinction (Av) of ~6-14. It has a slope of alpha=1.3-2 for the rho~r^-alpha profile for an equivalent density distribution (spherical or cylindrical geometry), and is thus consistent with free-fall gravitational collapse. Above Av~40, 60, and 140, we detect an excess that can be fitted by a flatter power law tail with alpha>2. It correlates with the central regions of the cloud (ridges/hubs) of size ~1 pc and densities above 10^4 cm^-3. This excess may be caused by physical processes that slow down collapse and reduce the flow of mass towards higher densities. Possible are: 1. rotation, which introduces an angular momentum barrier, 2. increasing optical depth and weaker cooling, 3. magnetic fields, 4. geometrical effects, and 5. protostellar feedback. The excess/second power-law tail is closely linked to high-mass star-formation though it does not imply a universal column density threshold for the formation of (high-mass) stars., MNRAS Letters, accepted 20.7.2015, in press
Published: 2015

29. Possible link between the power spectrum of interstellar filaments and the origin of the prestellar core mass function

Author: Davide Elia, Stefano Pezzuto, Vera Konyves, Frédérique Motte, Y. Shimajiri, Bilal Ladjelate, J. Di Francesco, Ph. André, A. Roy, Nicola Schneider, Derek Ward-Thompson, Tracey Hill, M. Benedettini, P. Palmeirim, G. J. White, Eugenio Schisano, Nicolas Peretto, F. Louvet, Luigi Spinoglio, Doris Arzoumanian, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Physics and Astronomy [Cardiff], Cardiff University, FORMATION STELLAIRE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Department of Physics and Astronomy [Victoria], University of Victoria [Canada] (UVIC), Joint ALMA Observatory (JAO), National Radio Astronomy Observatory (NRAO)-European Southern Observatory (ESO), Departamento de Astronomía, Universidad de Chile, Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Department of Physics and Astronomy [Milton Keynes], The Open University [Milton Keynes] (OU), ANR-11-BS56-0010,STARFICH,Vers une vision unifiée de la formation stellaire dans les galaxies : Origine de la structure filamentaire du milieu interstellaire, des cœurs pré-stellaires et des amas protostellaires vus avec Herschel(2011), European Project: 291294,EC:FP7:ERC,ERC-2011-ADG_20110209,ORISTARS(2012), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Universidad de Chile = University of Chile [Santiago] (UCHILE), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: Initial mass function, Evolution, ISM: structure, Stars: formation, Characteristic indices, FOS: Physical sciences, F500, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Spectral line, Power spectrum, Compressible turbulence, Gravitation, Protein filament, Functions, Mass functions, QC, Astrophysics::Galaxy Astrophysics, Physics, Turbulence, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Molecular cloud, Gaussian-like distributions, Spectral density, Astronomy and Astrophysics, Empirical correlations, Astrophysics - Astrophysics of Galaxies, Stars, Spectrum analysis, Amplitude, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: Two major features of the prestellar CMF are: 1) a broad peak below 1 Msun, presumably corresponding to a mean gravitational fragmentation scale, and 2) a characteristic power-law slope, very similar to the Salpeter slope of the stellar initial mass function (IMF) at the high-mass end. While recent Herschel observations have shown that the peak of the prestellar CMF is close to the thermal Jeans mass in marginally supercritical filaments, the origin of the power-law tail of the CMF/IMF at the high-mass end is less clear. Inutsuka (2001) proposed a theoretical scenario in which the origin of the power-law tail can be understood as resulting from the growth of an initial spectrum of density perturbations seeded along the long axis of filaments by interstellar turbulence. Here, we report the statistical properties of the line-mass fluctuations of filaments in nearby molecular clouds observed with Herschel using a 1-D power spectrum analysis. The observed filament power spectra were fitted by a power-law function $(P_{true}(s) \propto s^{\alpha})$ after removing the effect of beam convolution at small scales. A Gaussian-like distribution of power-spectrum slopes was found centered at -1.6, close to that of the one-dimensional velocity power spectrum generated by subsonic Kolomogorov turbulence (-1.67). An empirical correlation, $P^{0.5}(s_0) \propto ^{1.4 \pm 0.1} $, was also found between the amplitude of each filament power spectrum $P(s_0)$ and the mean column density along the filament $$. Finally, the dispersion of line-mass fluctuations along each filament $\sigma_{\rm M_{line}}$ was found to scale with the physical length $L$ of the filament, roughly as $\sigma_{M_{line}} \propto L^{0.7}$. Overall, our results are consistent with the suggestion that the bulk of the CMF/IMF results from the gravitational fragmentation of filaments., Comment: 10 pages, 12 figures, Accepted for publication in Astronomy and Astrophysics journal
Published: 2015

30. Herschel observations of B1-bS and B1-bN: two ﬁrst hydrostatic core candidates in the Perseus star-forming cloud

Author: S. Pezzuto, D. Elia, E. Schisano, J. Di Francesco, S. Sadavoy, P. André, M. Benedettini, J. P. Bernard, A. M. di Giorgio, A. Facchini, M. Hennemann, T. Hill, V. Könyves, S. Molinari, F. Motte, Q. Nguyen Luong, N. Peretto, M. Pestalozzi, D. Polychroni, K. L. J. Rygl, P. Saraceno, N. Schneider, L. Spinoglio, L. Testi, D. Ward Thompson, G. J. White, STRAFELLA, Francesco, S., Pezzuto, D., Elia, E., Schisano, Strafella, Francesco, J., Di Francesco, S., Sadavoy, P., André, M., Benedettini, J. P., Bernard, A. M., di Giorgio, A., Facchini, M., Hennemann, T., Hill, V., Könyve, S., Molinari, F., Motte, Q., Nguyen Luong, N., Peretto, M., Pestalozzi, D., Polychroni, K. L. J., Rygl, P., Saraceno, N., Schneider, L., Spinoglio, L., Testi, D., Ward Thompson, and G. J., White
Subjects: protostelle, formazione stellare
Abstract: We report far-infrared Herschel observations obtained between 70 μm and 500 μm of two star-forming dusty condensations, B1-bS and B1-bN, in the B1 region of the Perseus star-forming cloud. In the western part of the Perseus cloud, B1-bS is the only source detected in all six PACS and SPIRE photometric bands, but it is not visible in the Spitzer map at 24 μm. B1-bN is clearly detected between 100 μm and 250 μm. We have ﬁtted the spectral energy distributions of these sources to derive their physical properties, and ﬁnd that a simple greybody model fails to reproduce the observed spectral energy distributions. At least a two-component model is required, consisting of a central source surrounded by a dusty envelope. The properties derived from the ﬁt, however, suggest that the central source is not a Class 0 object. We then conclude that while B1-bS and B1-bN appear to be more evolved than a pre-stellar core, the best-ﬁt models suggest that their central objects are younger than a Class 0 source. Hence, they may be good candidates to be examples of the ﬁrst hydrostatic core phase. The projected distance between B1-bS and B1-bN is a few Jeans lengths. If their physical separation is close to this value, this pair would allow studying the mutual interactions between two forming stars at a very early stage of their evolution.
Published: 2012

31. Millimetre observations of the IRAS 18162−2048 outflow: evidence for cloud disruption around an intermediate-mass protostar

Author: Leonardo Testi, M. Benedettini, Alberto Noriega-Crespo, and Sergio Molinari
Subjects: Physics, Stars, Nebula, Free molecular flow, Space and Planetary Science, Star formation, Molecular cloud, Protostar, Astronomy, Astronomy and Astrophysics, Outflow, Astrophysics, Line (formation)
Abstract: In order to study the morphology and the dynamics of the molecular outflow associated with IRAS 18162−2048, a wide area of ∼95 arcmin 2 around the source has been mapped by means of CO and 13 CO (1‐0) lines, and has been complemented by a map of a smaller region surrounding the high-mass object using the C 18 O (1‐0) and CH3OH (2k‐1k) and (3k‐2k) transitions. The lines profile reveals the presence of several velocity components among which two major line components at 11.9 and 12.8 km s −1 have been detected in all the tracers. Simple morphological and energetic considerations led us to interpret the observations in a relatively straightforward scenario in which the powerful jet ejected by IRAS 18162−2048 sets a big portion of the surrounding molecular cloud into motion. The energy and momentum deposited by the flow break the cloud apart, shifting the northern region to a blue velocity and the southern region to a red velocity, and giving rise to a giant outflow. We calculated the physical parameters of the outflow, which make the IRAS 18162−2048 outflow one of the most massive (M = 570 M� ) and energetic (K > 10 46 erg) known. Despite the intrinsic difficulties in giving a precise value of the age and of the inclination angle of the flow, we used different methods to derive a reliable estimate. Our data show evidence in favour of a small inclination angle (
Published: 2004

32. Shocked gas around Cepheus A: evidence for multiple outflows from H2S and SO2observations

Author: Paola Caselli, M. Benedettini, C. Codella, and Rafael Bachiller
Subjects: Physics, Wavelength, Chemical models, Space and Planetary Science, Young stellar object, Astronomy, Astronomy and Astrophysics, Millimeter, Outflow, Astrophysics, Excitation, Collimated light, Line (formation)
Abstract: The Cepheus A star-forming region has been investigated through a multiline H 2 S and SO 2 survey at millimetre wavelengths. Large-scale maps and high-resolution line profiles reveal the occurrence of several outflows. CepA East is associated with multiple mass-loss processes: in particular, we detect a 0.6-pc jet-like structure which shows for the first time that the Cep A East young stellar objects are driving a collimated outflow moving towards the south. The observed outflows show different clumps associated with definitely different H 2 S/SO 2 integrated emission ratios, indicating that the gas chemistry in Cepheus A has been altered by the passage of shocks. H 2 S appears to be more abundant than SO 2 in high-velocity clumps, in agreement with chemical models. However, we also find quite small H 2 S linewidths, suggestive of regions where the evaporated H 2 S molecules had enough time to slow down but not to freeze out on to dust grains. Finally, comparison between the line profiles indicates that the excitation conditions increase with the velocity, as expected for a propagation of collimated bow shocks.
Published: 2003

33. Comparing SWAS and ISO observations of water in outflows

Author: Paul F. Goldsmith, Teresa Giannini, Brunella Nisini, Paolo Saraceno, M. Benedettini, and Serena Viti
Subjects: jets, Physics, Chemical models, abundances, Space and Planetary Science, Flux, molecules, Astronomy and Astrophysics, Outflow, Astrophysics, outflows, Water vapor, Line (formation)
Abstract: We present a detailed comparison of SWAS and ISO observations of H 2 O emission in a sample of outflows. By taking into consideration the different methods used to derive the fractional water abundance, we find that, despite the initial apparent discrepancies, there is satisfactory agreement between ISO and SWAS results for the outflows observed by both satellites. Such an agreement is reached by assuming that most of the detected water comes from a single region smaller than both the ISO and SWAS beam apertures and considering temperatures higher (T > 100 K) and density lower (n(H 2 ) < 2 x 10 6 cm - 3 ) than previously adopted. The ratio between the integrated flux of the ortho-H 2 O 2 1 2 -1 0 1 line at 179.5 μm observed by ISO and the fundamental ortho-H 2 O 1 1 0 -1 0 1 line at 538.3 μm observed by SWAS is always smaller (never by more than a factor of 7) than the expected ratio. We propose that the fundamental ortho-H 2 O transition has a contribution from a cooler gas component to which SWAS is sensitive but which is not traced by ISO. We conclude that, while ISO and SWAS observations are consistent with chemical models predicting a significant enhancement of water vapor abundance in outflow regions, the explanation for the low water abundance derived from SWAS observations of the cold ISM is still unclear.
Published: 2002

34. SO and SiO emission around the young cluster in the CB 34 globule

Author: Rafael Bachiller, C. Codella, M. Benedettini, and F. Scappini
Subjects: Physics, Wavelength, Space and Planetary Science, Young stellar object, Phase (matter), Spectral properties, Cluster (physics), Astronomy, Protostar, Astronomy and Astrophysics, Millimeter, Astrophysics, Spatial distribution
Abstract: The globule CB 34, which harbours a cluster of class 0 young stellar object (YSO) protostars, has been investigated through a multiline SO and SiO survey at millimetre wavelengths. The SO data reveal that the globule consists of three quiescent high-density (∼105 cm−3) clumps, labelled A, B and C, with sizes of ∼0.2–0.3 pc. The SiO data provide evidence for high-velocity gas across the globule. Most likely, the high-velocity gas is distributed in three distinct high-velocity outflows associated with the YSOs in each of the three clumps. High-velocity SO features have been detected only towards the two brightest SiO outflows. These broad SO components exhibit spatial and spectral distributions which are consistent with those of the SiO emission, so they can also be used as tracers of the outflows. The comparison between the spatial and spectral properties of the SO and SiO emissions in the three clumps suggests different evolutionary stages for the embedded YSOs. In particular, the YSO associated with clump C exhibits some peculiarities, namely smaller SiO linewidths, lower SiO column densities, a lack of extended SiO structure and of SO wings, and the presence of a SO spatial distribution which is displaced with respect to the location of the YSO. This behaviour is well explained if the SiO and SO molecules which were produced at high velocities in the shocked region have been destroyed or slowed down because of the interaction with the ambient medium, and the chemistry is dominated again by low-temperature reactions. Thus our observations strongly suggest that the YSO in clump C is in a more evolved phase than the other members of the cluster.
Published: 2002

35. The density structure of the L1157 molecular outflow

Author: Gemma Busquet, Brunella Nisini, Claudio Codella, Serena Viti, Linda Podio, A. I. Gómez-Ruiz, Cecilia Ceccarelli, Bertrand Lefloch, and M. Benedettini
Subjects: Physics, Jet (fluid), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Shock (mechanics), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Molecule, Protostar, Outflow, Excitation, Line (formation)
Abstract: We present a multiline CS survey towards the brightest bow-shock B1 in the prototypical chemically active protostellar outflow L1157. We made use of (sub-)mm data obtained in the framework of the Chemical HErschel Surveys of Star forming regions (CHESS) and Astrochemical Surveys at IRAM (ASAI) key science programs. We detected $^{12}$C$^{32}$S, $^{12}$C$^{34}$S, $^{13}$C$^{32}$S, and $^{12}$C$^{33}$S emissions, for a total of 18 transitions, with $E_{\rm u}$ up to $\sim$ 180 K. The unprecedented sensitivity of the survey allows us to carefully analyse the line profiles, revealing high-velocity emission, up to 20 km s$^{-1}$ with respect to the systemic. The profiles can be well fitted by a combination of two exponential laws that are remarkably similar to what previously found using CO. These components have been related to the cavity walls produced by the $\sim$ 2000 yr B1 shock and the older ($\sim$ 4000 yr) B2 shock, respectively. The combination of low- and high-excitation CS emission was used to properly sample the different physical components expected in a shocked region. Our CS observations show that this molecule is highlighting the dense, $n_{\rm H_2}$ = 1--5 $\times$ 10$^{5}$ cm$^{-3}$, cavity walls produced by the episodic outflow in L1157. In addition, the highest excitation (E$_u$ $\geq$ 130 K) CS lines provide us with the signature of denser (1--5 $\times$ 10$^{6}$ cm$^{-3}$) gas, associated with a molecular reformation zone of a dissociative J-type shock, which is expected to arise where the precessing jet impacting the molecular cavities. The CS fractional abundance increases up to $\sim$ 10$^{-7}$ in all the kinematical components. This value is consistent with what previously found for prototypical protostars and it is in agreement with the prediction of the abundances obtained via the chemical code Astrochem., 11 pages, 10 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)
Published: 2014

36. Resolving the shocked gas in HH54 with Herschel: CO line mapping at high spatial and spectral resolution

Author: S. Cabrit, G. J. Herczeg, G. Olofsson, Per Bjerkeli, Kay Justtanont, Mario Tafalla, Bengt Larsson, René Liseau, G. Santangelo, C. Brinch, John H. Black, Lars E. Kristensen, Brunella Nisini, and M. Benedettini
Subjects: Shock wave, Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Space observatory, On board, Atmospheric radiative transfer codes, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Chamaeleon, Emission spectrum, Spectral resolution, 010303 astronomy & astrophysics
Abstract: The HH54 shock is a Herbig-Haro object, located in the nearby Chamaeleon II cloud. Observed CO line profiles are due to a complex distribution in density, temperature, velocity, and geometry. Resolving the HH54 shock wave in the far-infrared cooling lines of CO constrain the kinematics, morphology, and physical conditions of the shocked region. We used the PACS and SPIRE instruments on board the Herschel space observatory to map the full FIR spectrum in a region covering the HH54 shock wave. Complementary Herschel-HIFI, APEX, and Spitzer data are used in the analysis as well. The observed features in the line profiles are reproduced using a 3D radiative transfer model of a bow-shock, constructed with the Line Modeling Engine code (LIME). The FIR emission is confined to the HH54 region and a coherent displacement of the location of the emission maximum of CO with increasing J is observed. The peak positions of the high-J CO lines are shifted upstream from the lower J CO lines and coincide with the position of the spectral feature identified previously in CO(10-9) profiles with HIFI. This indicates a hotter molecular component in the upstream gas with distinct dynamics. The coherent displacement with increasing J for CO is consistent with a scenario where IRAS12500-7658 is the exciting source of the flow, and the 180 K bow-shock is accompanied by a hot (800 K) molecular component located upstream from the apex of the shock and blueshifted by -7 km s$^{-1}$. The spatial proximity of this knot to the peaks of the atomic fine-structure emission lines observed with Spitzer and PACS ([OI]63, 145 $\mu$m) suggests that it may be associated with the dissociative shock as the jet impacts slower moving gas in the HH54 bow-shock., Comment: 6 pages, 5 figures
Published: 2014

37. Reconstructing the density and temperature structure of prestellar cores from

Author: A. Roy, Ph. Andrxe9, P. Palmeirim, M. Attard, V. Kxf6nyves, N. Schneider, N. Peretto, A. Men’shchikov, D. Ward-Thompson, J. Kirk, M. Griffin, K. Marsh, A. Abergel, D. Arzoumanian, M. Benedettini, T. Hill, F. Motte, Q. Nguyen Luong, S. Pezzuto, A. Rivera-Ingraham, H. Roussel, K. L. J. Rygl, L. Spinoglio, D. Stamatellos, and G. White
Published: 2014

38. A Herschel and BIMA study of the sequential star formation near the W 48A H II region

Author: Cassandra Fallscheer, Stefano Pezzuto, Glenn J. White, Ph. André, Nicola Schneider, Sergio Molinari, Vera Könyves, Sharmila Goedhart, A. Marston, K. L. J. Rygl, D. Polychroni, Friedrich Wyrowski, M. R. Pestalozzi, Tracey Hill, Luigi Spinoglio, Davide Elia, Derek Ward-Thompson, M. Benedettini, Pierre Didelon, A. Rivera-Ingraham, Eugenio Schisano, A. M. di Giorgio, Quang Nguyen-Luong, Andy Gibb, Frédérique Motte, Max-Planck-Institut für Radioastronomie (MPIFR), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), foreign laboratories (FL), CERN [Genève], FORMATION STELLAIRE 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Antarctic Research a European Network for Astrophysics (ARENA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), School of Physics and Astronomy [Cardiff], Cardiff University, Engineering Department, University of Cambridge [UK] (CAM), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Consiglio Nazionale delle Ricerche (CNR), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: H II region, Hii regions, Young stellar object, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, F500, star formation, law.invention, ISM molecules, W-48A, law, ISM individual objects, Astrophysics::Solar and Stellar Astrophysics, Maser, Astrophysics::Galaxy Astrophysics, Physics, Molecular line, extinction, Star formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Molecular cloud, Astronomy, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, ISM clouds, Trustworthiness, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Outflow, dust
Abstract: We present the results of Herschel HOBYS photometric mapping combined with BIMA observations and additional archival data, and perform an in-depth study of the evolutionary phases of the star-forming clumps in W 48A and their surroundings. Age estimates for the compact sources were derived from bolometric luminosities and envelope masses, which were obtained from the dust continuum emission, and agree within an order of magnitude with age estimates from molecular line and radio data. The clumps in W 48A are linearly aligned by age (east-old to west-young): we find a ultra compact (UC) HII region, a young stellar object (YSO) with class II methanol maser emission, a YSO with a massive outflow, and finally the NH_2D prestellar cores from Pillai et al. This remarkable positioning reflects the (star) formation history of the region. We find that it is unlikely that the star formation in the W 48A molecular cloud was triggered by the UCHII region and discuss the Aquila supershell expansion as a mayor influence on the evolution of W 48A. We conclude that the combination of Herschel continuum data with interferometric molecular line and radio continuum data is important to derive trustworthy age estimates and interpret the origin of large scale structures through kinematic information., Comment: Accepted for publication in MNRAS, 22 pages, 21 figures, 5 tables
Published: 2014

39. A Herschel and BIMA study of the sequential star formation near the 48A HII region

Author: Rygl, K.L.J. Goedhart, S. Polychroni, D. Wyrowski, F. Motte, F. Elia, D. Nguyen-Luong, Q. Didelon, P. Pestalozzi, M. Benedettini, M. Molinari, S. André, P. Fallscheer, C. Gibb, A. di Giorgio, A.M. Hill, T. Könyves, V. Marston, A. Pezzuto, S. Rivera-Ingraham, A. Schisano, E. Schneider, N. Spinoglio, L. Ward-Thompson, D. White, G.J.
Abstract: We present the results of Herschel HOBYS (Herschel imaging survey of OB Young Stellar objects) photometricmapping combined with Berkeley Illinois Maryland Association (BIMA) observations and additional archival data, and perform an in-depth study of the evolutionary phases of the star-forming clumps in W 48A and their surroundings. Age estimates for the compact sources were derived from bolometric luminosities and envelope masses, which were obtained from the dust continuum emission, and agree within an order of magnitude with age estimates from molecular line and radio data. The clumps in W 48A are linearly aligned by age (east-old to west-young): we find a ultra-compact (UC) HII region, a young stellar object (YSO) with class II methanol maser emission, a YSO with a massive outflow and finally the NH2D prestellar cores from Pillai et al. This remarkable positioning reflects the (star) formation history of the region. We find that it is unlikely that the star formation in the W48A molecular cloud was triggered by the UC HII region and discuss the Aquila supershell expansion as a major influence on the evolution of W48A. We conclude that the combination of Herschel continuum data with interferometric molecular line and radio continuum data is important to derive trustworthy age estimates and interpret the origin of large-scale structures through kinematic information. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Published: 2014

40. The CHESS survey of the L1157-B1 bow-shock: high and low excitation water vapor

Author: Brunella Nisini, Sylvie Cabrit, Serena Viti, A. M. di Giorgio, Bertrand Lefloch, Gemma Busquet, Cecilia Ceccarelli, M. Benedettini, Claudio Codella, A. I. Gómez-Ruiz, Laurent Wiesenfeld, Antoine Gusdorf, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Spectral line, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, Outflow, Bow shock (aerodynamics), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], 010303 astronomy & astrophysics, Water vapor, Excitation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Line (formation)
Abstract: Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks resulting in substantial modifications of the abundance of several species. As part of the "Chemical Herschel Surveys of Star forming regions" guaranteed time key program, we aim at investigating the physical and chemical conditions of H20 in the brightest shock region B1 of the L1157 molecular outflow. We observed several ortho- and para-H2O transitions using HIFI and PACS instruments on board Herschel, providing a detailed picture of the kinematics and spatial distribution of the gas. We performed a LVG analysis to derive the physical conditions of H2O shocked material, and ultimately obtain its abundance. We detected 13 H2O lines probing a wide range of excitation conditions. PACS maps reveal that H2O traces weak and extended emission associated with the outflow identified also with HIFI in the o-H2O line at 556.9 GHz, and a compact (~10") bright, higher-excitation region. The LVG analysis of H2O lines in the bow-shock show the presence of two gas components with different excitation conditions: a warm (Tkin~200-300 K) and dense (n(H2)~(1-3)x10^6 cm-3) component with an assumed extent of 10" and a compact (~2"-5") and hot, tenuous (Tkin~900-1400 K, n(H2)~10^3-10^4 cm-3) gas component, which is needed to account for the line fluxes of high Eu transitions. The fractional abundance of the warm and hot H2O gas components is estimated to be (0.7-2)x10^{-6} and (1-3)x10^{-4}, respectively. Finally, we identified an additional component in absorption in the HIFI spectra of H2O lines connecting with the ground state level, probably arising from the photodesorption of icy mantles of a water-enriched layer at the edges of the cloud., Accepted for publication in A&A. 12 pages, 9 figures, 4 tables
Published: 2014

41. The Filamentary Structure of the Lupus 3 Molecular Cloud

Author: M. Benedettini
Subjects: Physics, Protein filament, Line-of-sight, Molecular cloud, Continuum (design consultancy), Lupus (constellation), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Single filament, Astrophysics::Galaxy Astrophysics, Line (formation), Dust emission
Abstract: We present the column density map of the Lupus 3 molecular cloud derived from the Herschel photometric maps. We compared the Herschel continuum maps, tracing the dense and cold dust emission, with the CS (2–1) map observed with the Mopra 22-m antenna, tracing the dense gas. Both the continuum and the CS maps show a well defined filamentary structure, with most of the dense cores being on the filaments. The CS (2–1) line shows a double peak in the central part of the longest filament due to the presence of two distinct gas components along this line of sight. Therefore, what seems a single filament in the Herschel map is actually the overlap of two kinematically distinct filaments. This case clearly shows that kinematical information is essential for the correct interpretation of filaments in molecular clouds.
Published: 2014

42. An ISO investigation of the MWC 297 circumstellar region

Author: Brunella Nisini, Teresa Giannini, M. Benedettini, Dario Lorenzetti, and Stefano Pezzuto
Subjects: Physics, Wavelength, Space and Planetary Science, Be star, Absorption band, Ionization, Spectral energy distribution, Circumstellar dust, Astronomy and Astrophysics, Astrophysics, Emission spectrum, Herbig Ae/Be star
Abstract: The ISO-SWS full grating spectrum (2.3-45 μ m) of the Herbig Be star MWC 297 is presented. The spectrum is dominated by a strong continuum with superimposed emission lines and features both in absorption and in emission. In particular, we detect in emission 23 Hi recombination lines of the Brackett, Pfund and Humphreys series and four PAH features, while in absorption two broad silicate bands at 9.7 and 16.4 μ m, solid CO 2 at 4.27 μ m and solid H 2 O at 2.96 μ m have been observed. The ISO-SWS spectrum has been combined with ISO-LWS data and ground based photometry to derive the spectral energy distribution (SED) from optical to radio wavelengths. The observed SED has been fitted with a model that assumes a spherical dusty envelope parametrized by density and temperature power laws, deriving suitable values for the spectral type (B2), the visual extinction (7.5 mag) and the distance (280 pc). Consistent determination of the extinction and estimates of both the source mass loss rate ($9\times 10^{-7} M_{\odot}$ yr -1 ) and the size of the emitting ionized region (30 stellar radii) have been derived by the analysis of the Hi recombination lines of the Brackett, Pfund and Humphreys series observed by ISO-SWS together with Paschen and Brackett lines observed from the ground. Some peculiarities have been observed in the ISO-SWS spectrum of this source: i ) the ratio between the column density of the solid $\rm CO_2$ and $\rm H_2O$ ($2.0\pm 1.5$) higher than the values usually observed and ii ) the presence of a silicate broad absorption band at 16.4 μ m stronger than the 9.7 μ m absorption. The observed silicate absorption features are probably due to the extended dusty cloud in which the star is embedded and their relative strengths could be evidence that they are composed by processed grains.
Published: 2001

43. TWO MASS DISTRIBUTIONS IN THE L 1641 MOLECULAR CLOUDS: THE

Author: D. Polychroni, E. Schisano, D. Elia, A. Roy, S. Molinari, P. Martin, Ph. Andrxe9, D. Turrini, K. L. J. Rygl, J. Di Francesco, M. Benedettini, G. Busquet, A. M. di Giorgio, M. Pestalozzi, S. Pezzuto, D. Arzoumanian, S. Bontemps, M. Hennemann, T. Hill, V. Kxf6nyves, A. Men'shchikov, F. Motte, Q. Nguyen-Luong, N. Peretto, N. Schneider, and G. White
Published: 2013

44. The B1 shock in the L1157 outflow as seen at high spatial resolution

Author: Frédéric Gueth, Serena Viti, Claudio Codella, A. I. Gómez-Ruiz, M. T. Beltrán, Rafael Bachiller, M. Benedettini, Cecilia Ceccarelli, Gemma Busquet, and Bertrand Lefloch
Subjects: Physics, Jet (fluid), Range (particle radiation), Shock (fluid dynamics), Velocity gradient, High velocity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Molecular physics, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Excited state, High spatial resolution, Outflow
Abstract: We present high spatial resolution (750 AU at 250 pc) maps of the B1 shock in the blue lobe of the L1157 outflow in four lines: CS (3-2), CH3OH (3_K-2_K), HC3N (16-15) and p-H2CO (2_02-3_01). The combined analysis of the morphology and spectral profiles has shown that the highest velocity gas is confined in a few compact (~ 5 arcsec) bullets while the lowest velocity gas traces the wall of the gas cavity excavated by the shock expansion. A large velocity gradient model applied to the CS (3-2) and (2-1) lines provides an upper limit of 10^6 cm^-3 to the averaged gas density in B1 and a range of 5x10^3< n(H2)< 5x10^5 cm^-3 for the density of the high velocity bullets. The origin of the bullets is still uncertain: they could be the result of local instabilities produced by the interaction of the jet with the ambient medium or could be clump already present in the ambient medium that are excited and accelerated by the expanding outflow. The column densities of the observed species can be reproduced qualitatively by the presence in B1 of a C-type shock and only models where the gas reaches temperatures of at least 4000 K can reproduce the observed HC3N column density., 13 pages, 12 figures
Published: 2013

45. Broad N2H+ emission towards the protostellar shock L1157-B1

Author: Cecilia Ceccarelli, Serena Viti, Paola Caselli, Gemma Busquet, Bertrand Lefloch, Linda Podio, M. Vasta, Claudio Codella, A. I. Gómez-Ruiz, Francesco Fontani, and M. Benedettini
Subjects: Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Charged particle, Shock (mechanics), Ion, chemistry.chemical_compound, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, Outflow, 010306 general physics, 010303 astronomy & astrophysics, Hyperfine structure, Line (formation), Carbon monoxide
Abstract: We present the first detection of N2H+ towards a low-mass protostellar outflow, namely the L1157-B1 shock, at about 0.1 pc from the protostellar cocoon. The detection was obtained with the IRAM 30-m antenna. We observed emission at 93 GHz due to the J = 1-0 hyperfine lines. The analysis of the emission coupled with the HIFI CHESS multiline CO observations leads to the conclusion that the observed N2H+(1-0) line originates from the dense (> 10^5 cm-3) gas associated with the large (20-25 arcsec) cavities opened by the protostellar wind. We find a N2H+ column density of few 10^12 cm-2 corresponding to an abundance of (2-8) 10^-9. The N2H+ abundance can be matched by a model of quiescent gas evolved for more than 10^4 yr, i.e. for more than the shock kinematical age (about 2000 yr). Modelling of C-shocks confirms that the abundance of N2H+ is not increased by the passage of the shock. In summary, N2H+ is a fossil record of the pre-shock gas, formed when the density of the gas was around 10^4 cm-3, and then further compressed and accelerated by the shock., ApJ, in press
Published: 2013

46. The first Hi-GAL observations of the outer Galaxy: a look to star formation in the third Galactic quadrant in the longitude range 216.5 < l < 225.5

Author: D. Ikhenaode, Eugenio Schisano, Lorenzo Piazzo, K. L. J. Rygl, Luca Olmi, Akira Mizuno, Hiroaki Yamamoto, Toshikazu Onishi, D. Polychroni, M. Benedettini, M. R. Pestalozzi, Y. Fukui, M. Veneziani, A. M. di Giorgio, Y. Maruccia, Sergio Molinari, T. Hayakawa, Nicola Schneider, Davide Elia, Stefano Pezzuto, Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Antarctic Research a European Network for Astrophysics (ARENA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), FORMATION STELLAIRE 2013, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), foreign laboratories (FL), CERN [Genève], National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Perseus Arm, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, ISM: clouds, Luminosity, Galaxy: structure, infrared: ISM, ISM: molecules, stars: formation, Space and Planetary Science, Astronomy and Astrophysics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, 010308 nuclear & particles physics, Star formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Galactic quadrant, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Galaxy, 13. Climate action, Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics
Abstract: We present the first Herschel PACS and SPIRE photometric observations in a portion of the outer Galaxy ($216.5^{\circ} \lesssim \ell \lesssim 225.5^{\circ}$ and $-2^{\circ} \lesssim b \lesssim 0^{\circ}$) as a part of the Hi-GAL survey. The maps between 70 and 500 $\mu$m, the derived column density and temperature maps, and the compact source catalog are presented. NANTEN CO(1-0) line observations are used to derive cloud kinematics and distances, so that we can estimate distance-dependent physical parameters of the compact sources (cores and clumps) having a reliable spectral energy distribution, that we separate in 255 proto-stellar and 688 starless. Both typologies are found in association with all the distance components observed in the field, up to $\sim 5.8$ kpc, testifying the presence of star formation beyond the Perseus arm at these longitudes. Selecting the starless gravitationally bound sources we identify 590 pre-stellar candidates. Several sources of both proto- and pre-stellar nature are found to exceed the minimum requirement for being compatible with massive star formation, based on the mass-radius relation. For the pre-stellar sources belonging to the Local arm ($d\lesssim1.5$ kpc) we study the mass function, whose high-mass end shows a power-law $N(\log M) \propto M^{-1.0 \pm 0.2}$. Finally, we use a luminosity vs mass diagram to infer the evolutionary status of the sources, finding that most of the proto-stellar are in the early accretion phase (with some cases compatible with a Class I stage), while for pre-stellar sources, in general, accretion has not started yet., Comment: Accepted by ApJ
Published: 2013

47. WHAT DETERMINES THE DENSITY STRUCTURE OF MOLECULAR CLOUDS? A CASE STUDY OF ORION B WITH

Author: N. Schneider, Ph. Andrxe9, V. Kxf6nyves, S. Bontemps, F. Motte, C. Federrath, D. Ward-Thompson, D. Arzoumanian, M. Benedettini, E. Bressert, P. Didelon, J. Di Francesco, M. Griffin, M. Hennemann, T. Hill, P. Palmeirim, S. Pezzuto, N. Peretto, A. Roy, K. L. J. Rygl, L. Spinoglio, and G. White
Published: 2013

48. Herschel Reveals Massive Cold Clumps in NGC 7538

Author: C. Fallscheer, M. A. Reid, J. Di Francesco, P. G. Martin, T. Hill, M. Hennemann, Q. Nguyen-Luong, F. Motte, A. Men'shchikov, Ph. André, D. Ward-Thompson, M. Griffin, J. Kirk, V. Konyves, K. L. J. Rygl, S. Sadavoy, M. Sauvage, N. Schneider, L. D. Anderson, M. Benedettini, J.-P. Bernard, S. Bontemps, A. Ginsburg, S. Molinari, D. Polychroni, A. Rivera-Ingraham, H. Roussel, L. Testi, G. White, J. P. Williams, C. D. Wilson, M. Wong, A. Zavagno, Riverine Landscapes Research Lab, Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, School of Physics and Astronomy [Cardiff], Cardiff University, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), FORMATION STELLAIRE 2013, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), European Southern Observatory (ESO), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Institute for Astronomy (IfA), University of Hawai‘i [Mānoa] (UHM), Fundació Privada Observatori Esteve Duran, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Young stellar object, Continuum (design consultancy), FOS: Physical sciences, Astronomy and Astrophysics, Imaging study, Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Stars, Spire, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Galaxy Astrophysics
Abstract: We present the first overview of the Herschel observations of the nearby high-mass star-forming region NGC 7538, taken as part of the Herschel imaging study of OB Young Stellar objects (HOBYS) Key Programme. These PACS and SPIRE maps cover an approximate area of one square degree at five submillimeter and far-infrared wavebands. We have identified 780 dense sources and classified 224 of those. With the intention of investigating the existence of cold massive starless or class 0-like clumps that would have the potential to form intermediate- to high-mass stars, we further isolate 13 clumps as the most likely candidates for followup studies. These 13 clumps have masses in excess of 40 M_sun and temperatures below 15 K. They range in size from 0.4 pc to 2.5 pc and have densities between 3x10^3 cm^-3 to 4x10^4 cm^-3. Spectral energy distributions are then used to characterize their energetics and evolutionary state through a luminosity-mass diagram. NGC 7538 has a highly filamentary structure, previously unseen in the dust continuum of existing submillimeter surveys. We report the most complete imaging to date of a large, evacuated ring of material in NGC 7538 which is bordered by many cool sources., 23 pages, 7 figures, 1 table, accepted by ApJ
Published: 2013

49. What determines the density structure of molecular clouds ? A case study of Orion B with Herschel

Author: P. Palmeirim, Vera Könyves, M. Hennemann, Nicola Schneider, Frédérique Motte, Glenn J. White, Ph. André, Doris Arzoumanian, A. Roy, J. Di Francesco, M. Benedettini, Sylvain Bontemps, Nicolas Peretto, Christoph Federrath, Matthew Joseph Griffin, Kazi L.J. Rygl, Stefano Pezzuto, Eli Bressert, Tracey Hill, L. Spinoglio, Derek Ward-Thompson, Pierre Didelon, FORMATION STELLAIRE 2013, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, School of Physics and Astronomy [Cardiff], Cardiff University, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Milieux aquatiques, écologie et pollutions (UR MALY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Antarctic Research a European Network for Astrophysics (ARENA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: Physics, 010308 nuclear & particles physics, Turbulence, Star formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Magnetic field, law.invention, Polaris, 13. Climate action, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), Intermittency, 0103 physical sciences, Log-normal distribution, Probability distribution, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: A key parameter to the description of all star formation processes is the density structure of the gas. In this letter, we make use of probability distribution functions (PDFs) of Herschel column density maps of Orion B, Aquila, and Polaris, obtained with the Herschel Gould Belt survey (HGBS). We aim to understand which physical processes influence the PDF shape, and with which signatures. The PDFs of Orion B (Aquila) show a lognormal distribution for low column densities until Av 3 (6), and a power-law tail for high column densities, consistent with a rho r^-2 profile for the equivalent spherical density distribution. The PDF of Orion B is broadened by external compression due to the nearby OB stellar aggregates. The PDF of a quiescent subregion of the non-star-forming Polaris cloud is nearly lognormal, indicating that supersonic turbulence governs the density distribution. But we also observe a deviation from the lognormal shape at Av>1 for a subregion in Polaris that includes a prominent filament. We conclude that (i) the point where the PDF deviates from the lognormal form does not trace a universal Av-threshold for star formation, (ii) statistical density fluctuations, intermittency and magnetic fields can cause excess from the lognormal PDF at an early cloud formation stage, (iii) core formation and/or global collapse of filaments and a non-isothermal gas distribution lead to a power-law tail, and (iv) external compression broadens the column density PDF, consistent with numerical simulations., Astrophysical Journal Letters, received: 2012 December 30; accepted 2013 February 26
Published: 2013

50. Two Mass Distributions in the L 1641 Molecular Clouds: The Herschel connection of Dense Cores and Filaments in Orion A

Author: D. Polychroni, Stefano Pezzuto, Nicolas Peretto, Doris Arzoumanian, A. Roy, Pierrick Martin, Ph. André, J. Di Francesco, Q. Nguyen-Luong, A. M. di Giorgio, Frédérique Motte, K. L. J. Rygl, Tracey Hill, G. J. White, Diego Turrini, Eugenio Schisano, Sergio Molinari, M. R. Pestalozzi, Vera Konyves, M. Benedettini, Nicola Schneider, Sylvain Bontemps, Alexander Men'shchikov, Davide Elia, Gemma Busquet, M. Hennemann, Milieux aquatiques, écologie et pollutions (UR MALY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), foreign laboratories (FL), CERN [Genève], FORMATION STELLAIRE 2013, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Consiglio Nazionale delle Ricerche (CNR), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Epilepsy Center Kork, Epilepsy Center Kork = Epilepsiezentrum Kork, SLAC National Accelerator Laboratory (SLAC), Stanford University, Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Pomies, Marie-Paule, Stanford Linear Accelerator Center (SLAC), and Stanford University [Stanford]
Subjects: FOS: Physical sciences, Astrophysics, macromolecular substances, 01 natural sciences, Power law, Flattening, 0103 physical sciences, [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Connection (algebraic framework), 010303 astronomy & astrophysics, Physics, Solar mass, [PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Mass distribution, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Molecular cloud, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, Diffuse cloud, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Galaxy Astrophysics
Abstract: We present the Herschel Gould Belt survey maps of the L1641 molecular clouds in Orion A. We extracted both the filaments and dense cores in the region. We identified which of dense sources are proto- or pre-stellar, and studied their association with the identified filaments. We find that although most (71%) of the pre-stellar sources are located on filaments there is still a significant fraction of sources not associated with such structures. We find that these two populations (on and off the identified filaments) have distinctly different mass distributions. The mass distribution of the sources on the filaments is found to peak at 4 Solar masses and drives the shape of the CMF at higher masses, which we fit with a power law of the form dN/dlogM \propto M^{-1.4+/-0.4}. The mass distribution of the sources off the filaments, on the other hand, peaks at 0.8 Solar masses and leads to a flattening of the CMF at masses lower than ~4 Solar masses. We postulate that this difference between the mass distributions is due to the higher proportion of gas that is available in the filaments, rather than in the diffuse cloud., Comment: Accepted for publication in the Astrophysical Journal Letters; 9 pages, 4 figures, 1 table
Published: 2013
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