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1. Low levels of methanol deuteration in the high-mass star-forming region NGC 6334I

Author: Todd R. Hunter, Michiel R. Hogerheijde, Vianney Taquet, Crystal L. Brogan, Ewine F. van Dishoeck, Eva G. Bøgelund, John C. Pearson, Niels F. W. Ligterink, Brett A. McGuire, and Low Energy Astrophysics (API, FNWI)
Subjects: Physics, Astrochemistry, Isotope, Thermodynamic equilibrium, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Submillimeter Array, Astrophysics - Solar and Stellar Astrophysics, Deuterium, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Millimeter, Spectral resolution, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The abundance of deuterated molecules in a star-forming region is sensitive to the environment in which they are formed. Deuteration fractions therefore provide a powerful tool for studying the physical and chemical evolution of a star-forming system. While local low-mass star-forming regions show very high deuteration ratios, much lower fractions are observed towards Orion and the Galactic Centre. We derive methanol deuteration fractions at a number of locations towards the high-mass star-forming region NGC 6334I, located at a mean distance of 1.3 kpc, and discuss how these can shed light on the conditions prevailing during its formation. We use high sensitivity, high spatial and spectral resolution observations obtained with ALMA to study transitions of the less abundant, optically thin, methanol-isotopologues: (13)CH3OH, CH3(18)OH, CH2DOH and CH3OD, detected towards NGC 6334I. Assuming LTE and excitation temperatures of 120-330 K, we derive column densities for each of the species and use these to infer CH2DOH/CH3OH and CH3OD/CH3OH fractions. Interestingly, the column densities of CH3OD are consistently higher than those of CH2DOH throughout the region. All regions studied in this work show CH2DOH/CH3OH as well as CH2DOH/CH3OD ratios that are considerably lower than those derived towards low-mass star-forming regions and slightly lower than those derived for the high-mass star-forming regions in Orion and the Galactic Centre. The low ratios indicate a grain surface temperature during formation ~30 K, for which the efficiency of the formation of deuterated species is significantly reduced., Comment: Accepted for publication in Astronomy & Astrophysics
Published: 2018
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2. Survey of cold water lines in protoplanetary disks: indications of systematic volatile depletion

Author: Ilse Cleeves, David A. Neufeld, Edwin A. Bergin, John C. Pearson, Carsten Dominik, G. A. Blake, Ewine F. van Dishoeck, Davide Fedele, Michiel R. Hogerheijde, Gary J. Melnick, Umut A. Yildiz, Simon Bruderer, Fujun Du, Dariusz C. Lis, Low Energy Astrophysics (API, FNWI), 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), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, École normale supérieure - Paris (ENS-PSL), and NASA-California Institute of Technology (CALTECH)
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, Abundance (chemistry), chemistry.chemical_element, FOS: Physical sciences, Astrophysics, 01 natural sciences, Oxygen, Settling, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Line (formation), [PHYS]Physics [physics], Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Planetary system, Mass ratio, Astrophysics - Astrophysics of Galaxies, Photoevaporation, Astrophysics - Solar and Stellar Astrophysics, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We performed very deep searches for 2 ground-state water transitions in 13 protoplanetary disks with the HIFI instrument on-board the Herschel Space Observatory, with integration times up to 12 hours per line. Two other water transitions that sample warmer gas were also searched for with shallower integrations. The detection rate is low, and the upper limits provided by the observations are generally much lower than predictions of thermo-chemical models with canonical inputs. One ground-state transition is newly detected in the stacked spectrum of AA Tau, DM Tau, LkCa 15, and MWC 480. We run a grid of models to show that the abundance of gas-phase oxygen needs to be reduced by a factor of at least ~100 to be consistent with the observational upper limits (and positive detections) if a dust-to-gas mass ratio of 0.01 were to be assumed. As a continuation of previous ideas, we propose that the underlying reason for the depletion of oxygen (hence the low detection rate) is the freeze-out of volatiles such as water and CO onto dust grains followed by grain growth and settling/migration, which permanently removes these gas-phase molecules from the emissive upper layers of the outer disk. Such depletion of volatiles is likely ubiquitous among different disks, though not necessarily to the same degree. The volatiles might be returned back to the gas phase in the inner disk (within about 15 AU), which is consistent with current constraints. Comparison with studies on disk dispersal due to photoevaporation indicates that the timescale for volatile depletion is shorter than that of photoevaporation., Comment: Accepted for publication in ApJ
Published: 2017
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3. TERAHERTZ SPECTROSCOPY OF THE BENDING VIBRATIONS OF ACETYLENE12C2H2

Author: Shanshan Yu, Brian J. Drouin, and John C. Pearson
Subjects: Physics, Space and Planetary Science, Terahertz radiation, Astronomy and Astrophysics, Bending, Atomic physics, Atmospheric temperature range, Spectral resolution, Spectroscopy, Microwave, Terahertz spectroscopy and technology, Carbide
Abstract: Twenty P-branch transitions of 12C2H2 have been measured in the 0.8-1.6 THz region of its bending vibrational difference band. The accuracy of these measurements is estimated to be 100 kHz. The 12C2H2 molecules were generated under room temperature by passing 150 mTorr H2O vapor through calcium carbide (CaC2) powder. The observed transitions were modeled together with prior far-infrared data involving the bending levels with . Frequency predictions of 12C2H2 in the terahertz region have been greatly improved by adding the first data of "microwave" precision. The new measurements and predictions reported here will facilitate the analyses of astronomical observations by the high spectral resolution telescopes such as Herschel, SOFIA, and ALMA.
Published: 2009

4. NEW GROUND-STATE MEASUREMENTS OF ETHYL CYANIDE

Author: Carolyn S. Brauer, John C. Pearson, Shanshan Yu, and Brian J. Drouin
Subjects: Physics, Terahertz radiation, Cyanide, Astronomy and Astrophysics, Methods laboratory, Spectral line, Interstellar medium, chemistry.chemical_compound, chemistry, Space and Planetary Science, Rotational spectrum, Propionitrile, Atomic physics, Ground state
Abstract: The spectrum of ethyl cyanide, or propionitrile (CH3CH2CN), has been repeatedly observed in the interstellar medium with large column densities and surprisingly high temperatures in hot core sources. The construction of new, more sensitive, observatories accessing higher frequencies such as Herschel, ALMA, and SOFIA have made it important to extend the laboratory data for ethyl cyanide to coincide with the capabilities of the new instruments. We report extensions of the laboratory measurements of the rotational spectrum of ethyl cyanide in its ground vibrational state to 1.6 THz. A global analysis of the ground state, which includes all of the previous data and 3356 newly assigned transitions, has been fitted to within experimental error to J = 132, K = 36, using both Watson A-reduced and Watson S-reduced Hamiltonians.
Published: 2009

5. TERAHERTZ SPECTROSCOPY AND GLOBAL ANALYSIS OF THE BENDING VIBRATIONS OF ACETYLENE12C2D2

Author: Valerio Lattanzi, Shanshan Yu, Brian J. Drouin, Adam Walters, Herbert M. Pickett, and John C. Pearson
Subjects: Physics, business.industry, Terahertz radiation, Infrared, Astronomy and Astrophysics, Bending, Terahertz spectroscopy and technology, Optics, Space and Planetary Science, Molecular vibration, Pure bending, Atomic physics, Spectroscopy, business, Microwave
Abstract: Two hundred and fifty-one 12C2D2 transitions have been measured in the 0.2-1.6 THz region of its ν5–ν4 difference band and 202 of them were observed for the first time. The accuracy of these measurements is estimated to be ranging from 50 kHz to 100 kHz. The 12C2D2 molecules were generated under room temperature by passing 120-150 mTorr D2O vapor through calcium carbide (CaC2) powder. A multistate analysis was carried out for the bending vibrational modes ν4 and ν5 of 12C2D2, which includes the lines observed in this work and prior microwave, far-infrared and infrared data on the pure bending levels. Significantly improved molecular parameters were obtained for 12C2D2 by adding the new measurements to the old data set, which had only 10 lines with microwave measurement precision. New frequency and intensity predictions have been made based on the obtained molecular parameters. The more precise measurements and new predictions reported here will support the analyses of astronomical observations by the future high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA, which will work in the terahertz spectral region.
Published: 2009

6. TERAHERTZ SPECTROSCOPY AND GLOBAL ANALYSIS OF H 3 O +

Author: John C. Pearson, Shanshan Yu, Brian J. Drouin, and Herbert M. Pickett
Subjects: Physics, Spectrometer, Terahertz radiation, Infrared, business.industry, Frequency multiplier, Astronomy and Astrophysics, Terahertz spectroscopy and technology, Ion, Optics, Space and Planetary Science, Atomic physics, business, Ground state, Spectroscopy, Astrophysics::Galaxy Astrophysics
Abstract: Eight ground-state inversion transitions of H3O+ in the 0.9-1.6 THz region have been measured using the frequency multiplier submillimeter spectrometer at Jet Propulsion Laboratory. The accuracy of these measurements is estimated to be 300 kHz. The ions were generated in a dc discharge through a gas mixture of a few mTorr of H2 and 30 mTorr of H2O. A multistate analysis was carried out for H3O+, which includes the lines observed in this work, previous submillimeter and terahertz inversion transitions in the ground state, and previous infrared data on all the four vibrational fundamental bands. Accurate molecular parameters were obtained with taking into account the strong Coriolis interaction between the symmetric OH stretching mode (ν1) and the doubly degenerate asymmetric OH stretching mode (ν3). Fequency predictions, particularly for high-J transitions in the ground state and in the ν1 and ν3 fundamental bands, have been greatly improved by including ~ 200 more high-J transitions in our analysis, which were excluded in previous analyses. The more precise measurements and new predictions reported here will support the analyses of astronomical observations by the future high-resolution spectroscopy telescopes, such as Herschel, SOFIA, and ALMA.
Published: 2008

7. THE 40-FOOT SOLAR ECLIPSE CAMERA OF THE LICK OBSERVATORY

Author: John C. Pearson and Wayne Orchiston
Subjects: History, Physics and Astronomy (miscellaneous), Astronomy and Astrophysics
Published: 2008

8. Rotational Spectrum of the Formyl Cation, HCO+, to 1.2 THz

Author: Brian J. Drouin, John C. Pearson, Valerio Lattanzi, and Adam Walters
Subjects: Physics, Formyl cation, Space and Planetary Science, Terahertz radiation, Rotational spectrum, Astronomy and Astrophysics, Millimeter, Isotopologue, Astrophysics, Atomic physics, Atacama Large Millimeter Array, Spectroscopy, Microwave
Abstract: A variety of high-quality spectroscopic studies have contributed to knowledge of the formyl cation, HCO+, and its rare isotopologues, but technical limitations have previously limited precise determinations of the far-infrared, or terahertz spectrum. This study extends the microwave, millimeter, and submillimeter spectroscopy of HCO+ into the terahertz range. The resulting measurements and predictions are of sufficient coverage to adequately address astrophysical questions about this species using the Herschel Space Observatory or the Atacama Large Millimeter Array.
Published: 2007

9. The Millimeter‐ and Submillimeter‐Wave Spectrum of the G t Conformer of n ‐Propanol ( n ‐CH 3 CH 2 CH 2 OH)

Author: Elizabeth Trosell, Frank C. De Lucia, John C. Pearson, Atsuko Maeda, Robert K. Bohn, Eric Herbst, and Joanna Riccobono
Subjects: Physics, Interstellar medium, Astrochemistry, Space and Planetary Science, Spectrum (functional analysis), Molecule, Astronomy and Astrophysics, Observable, Millimeter, Atomic physics, Conformational isomerism, Spectral line
Abstract: As part of our continuing spectroscopic program of measuring the rotational spectra of large gas-phase molecules that may exist in observable quantities in the interstellar medium, we have studied the millimeter- and submillimeter-wave spectrum of the alcohol n-propanol (n-CH3CH2CH2OH), a straight-chain molecule with one more carbon atom than ethanol, which has already been detected in hot molecular cores. Although the molecule is thought to exist in five different conformers, we have only studied what is most likely to be the Gauche-trans (Gt) conformer, and analyzed over 2800 lines through 375 GHz in frequency. These lines have been added to both previously and newly measured rotational lines at lower frequencies. The global data set has been fitted to experimental accuracy, allowing us to determine accurate spectral parameters so as to predict useful frequencies for many more transitions of the conformer.
Published: 2006

10. First Detection of Doubly Deuterated Hydrogen Sulfide

Author: Charlotte Vastel, Thomas G. Phillips, John C. Pearson, and Cecilia Ceccarelli
Subjects: Physics, 010504 meteorology & atmospheric sciences, Hydrogen sulfide, Astrophysics (astro-ph), Formaldehyde, Analytical chemistry, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Isotopomers, Interstellar medium, chemistry.chemical_compound, Caltech Submillimeter Observatory, chemistry, Deuterium, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Molecule, Methanol, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: This work was carried out with using the Caltech Submillimeter Observatory and presents the observational study of HDS and D2S towards a sample of Class 0 sources, and dense cores. We report the first detection of doubly deuterated hydrogen sulfide (D2S) in two dense cores and analyze the chemistry of these molecules aiming to help understand the deuteration processes in the interstellar medium. The observed values of the D2S/HDS ratio, and upper limits, require an atomic D/H ratio in the accreting gas of 0.1-1. The study presented in this Letter supports the hypothesis that formaldehyde, methanol and hydrogen sulfide are formed on the grain surfaces, during the cold pre-stellar core phase, where the CO depleted gas has large atomic D/H ratios. The high values for the D/H ratios are consistent with the predictions of a recent gas-phase chemical model that includes H3+ and its deuterated isotopomers, H2D+, D2H+ and D3+ (Roberts et al. 2003)., 14 pages, 2 figures. accepted in ApJL
Published: 2003

11. Acetone: Laboratory Assignments and Predictions through 620 GH <scp>z</scp> for the Vibrational‐Torsional Ground State

Author: Frank J. Lovas, Peter Groner, John C. Pearson, Brian J. Drouin, Sieghard Albert, Frank C. De Lucia, and Eric Herbst
Subjects: Physics, Work (thermodynamics), Internal rotation, Astronomy and Astrophysics, Rotation, chemistry.chemical_compound, chemistry, Space and Planetary Science, Acetone, Rotational spectrum, Molecule, Dimethyl ether, Atomic physics, Ground state
Abstract: The acetone molecule has a complex rotational spectrum arising from the internal rotation of two methyl tops and their interaction with each other and the rigid-body rotation of the molecule. Here we report the measurement and assignment of a large number of new rotational-torsional transitions of acetone in the vibrational-torsional ground state at frequencies of up to 620 GHz. The newly measured lines have been combined with previously measured transition frequencies and fitted by a procedure used successfully for dimethyl ether. From the fit to the global data set, we have extracted parameters that have enabled us to predict accurately the frequencies and intensities of over 10,000 lines of possible astronomical importance at frequencies of up to 620 GHz. The detection of interstellar acetone was first reported by Combes et al. based on two transitions with partially resolved internal rotation structure. The present work will aid further interstellar studies to verify acetone as an interstellar constituent.
Published: 2002

12. Herschel Observations of Extraordinary Sources

Author: Nuria Marcelino, Maria Kleshcheva, Floris van der Tak, Peter Schilke, G. B. Esplugues, Justin L. Neill, Martin Emprechtinger, Nathan R. Crockett, Rene Plume, Brett A. McGuire, Harshal Gupta, Thomas G. Phillips, Edwin A. Bergin, Steven D. Lord, Tom Bell, Dariusz C. Lis, Belén Tercero, Cécile Favre, José Cernicharo, Shanshan Yu, John C. Pearson, Geoffrey A. Blake, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Equipe de Recherche en Ingénierie des Connaissances (ERIC), Université Lumière - Lyon 2 (UL2), I. Physikalisches Institut [Köln], Universität zu Köln, Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Public Health and General Practice, University of Otago [Dunedin, Nouvelle-Zélande], CalTech-CSO (CSO), California Institute of Technology (CALTECH), Department of Physics and Astronomy [Calgary], University of Calgary, SRON Netherlands Institute for Space Research (SRON), Dpt. Astrofisica Molecular e Infrarroja, CSIS - IEM, and Astronomy
Subjects: ISM: individual objects: Orion KL, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Spectral line, ISM: abundances, law.invention, Telescope, law, Astrophysics::Solar and Stellar Astrophysics, Isotopologue, Spectral resolution, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Physics, [PHYS]Physics [physics], Nebula, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, ISM: molecules, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Energy (signal processing)
Abstract: We present a comprehensive analysis of a broad band spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at a resolution of 1.1 MHz. These observations thus encompass the largest spectral coverage ever obtained toward this high-mass star-forming region in the sub-mm with high spectral resolution, and include frequencies $>$ 1 THz where the Earth's atmosphere prevents observations from the ground. In all, we detect emission from 39 molecules (79 isotopologues). Combining this dataset with ground based mm spectroscopy obtained with the IRAM 30 m telescope, we model the molecular emission from the mm to the far-IR using the XCLASS program which assumes local thermodynamic equilibrium (LTE). Several molecules are also modeled with the MADEX non-LTE code. Because of the wide frequency coverage, our models are constrained by transitions over an unprecedented range in excitation energy. A reduced $��^{2}$ analysis indicates that models for most species reproduce the observed emission well. In particular, most complex organics are well fit by LTE implying gas densities are high ($>$10$^6$ cm$^{-3}$) and excitation temperatures and column densities are well constrained. Molecular abundances are computed using H$_{2}$ column densities also derived from the HIFI survey. The distribution of rotation temperatures, $T_{\rm rot}$, for molecules detected toward the hot core is significantly wider than the compact ridge, plateau, and extended ridge $T_{\rm rot}$ distributions, indicating the hot core has the most complex thermal structure., Accepted to ApJ. 92 pages, 24 Figures, 9 Tables. Public data products may not be available yet
Published: 2014

13. Ubiquitous argonium (ArH + ) in the diffuse interstellar medium: A molecular tracer of almost purely atomic gas

Author: Edith Falgarone, Peter Schilke, Benjamin Godard, John C. Pearson, Thomas Moeller, Edwin A. Bergin, Nick Indriolo, Karl M. Menten, Maryvonne Gerin, Holger S. P. Müller, Dariusz C. Lis, Mark Wolfire, Álvaro Sánchez-Monge, David A. Neufeld, Claudia Comito, John H. Black, Benjamin Winkel, Max Planck Institute for Radio Astronomy, Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, 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), Indiana University Cyclotron Facility (IUCF), Indiana University [Bloomington], Indiana University System-Indiana University System, Max-Planck-Institut für Radioastronomie (MPIFR), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Laboratoire de Radioastronomie (LRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), 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), École normale supérieure - Paris (ENS-PSL), and 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)
Subjects: Hydrogen, FOS: Physical sciences, chemistry.chemical_element, Context (language use), Astrophysics, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Spectral line, Physics::Plasma Physics, Ionization, 0103 physical sciences, Isotopologue, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 0104 chemical sciences, Interstellar medium, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Content (measure theory), Atomic physics, Absorption (chemistry), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We describe the assignment of a previously unidentified interstellar absorption line to ArH$^+$ and discuss its relevance in the context of hydride absorption in diffuse gas with a low H$_2$ fraction. The column densities along several lines of sight are determined and discussd in the framework of chemical models. The column densities of ArH$^+$ are compared to those of other species, tracing interstellar medium (ISM) components with different H$_2$ abundances. Chemical models are constructed, taking UV radiation and cosmic ray ionization into account. Due to the detection of two isotopologues, $^{36}$ArH$^+$ and $^{38}$ArH$^+$, we are confident about the carrier assignment to ArH$^+$. NeH$^+$ is not detected with a limit of [NeH$^+$]/[ArH$^+$] $\le$ 0.1. The derived column densities agree well with the predictions of chemical models. ArH$^+$ is a unique tracer of gas with a fractional H$_2$ abundance of $10^{-4}- 10^{-3}$ and shows little correlation with H$_2$O$^+$, which traces gas with a fractional H$_2$ abundance of $\approx $0.1. A careful analysis of variations in the ArH$^+$, OH$^+$, H$_2$O$^+$ and HF column densities promises to be a faithful tracer of the distribution of the H$_2$ fractional abundance, providing unique information on a poorly known phase in the cycle of interstellar matter, its transition from atomic diffuse gas to dense molecular gas traced by CO emission. Abundances of these species put strong observational constraints upon magnetohydrodynamical (MHD) simulations of the interstellar medium, and potentially could evolve into a tool to characterize the ISM. Paradoxically, the ArH$^+$ molecule is a better tracer of \new{almost} purely atomic hydrogen gas than H{\sc i} itself, since H{\sc i} can also be present in gas with a significant molecular content, but ArH$^+$ singles out gas that is $>99.9$\% atomic., 12 pages, 11 figures, Astronomy and Astrophysics, accepted revised version: previous version had column density of SgrB2 sources wrong
Published: 2014

14. The effect of sideband ratio on line intensity for Herschel/HIFI

Author: R. Shipman, Frank Helmich, Michael Olberg, J. Braine, Volker Ossenkopf, John C. Pearson, Bertrand Delforge, David Teyssier, Ronan Higgins, Colin Borys, Claudia Comito, European Space Astronomy Centre (ESAC), European Space Agency (ESA), FORMATION STELLAIRE 2014, 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), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), and Astronomy
Subjects: Heterodyne, Sideband ratio, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], FOS: Physical sciences, Astrophysics, Optics, Far infrared, Herschel, Calibration, Instrumentation and Methods for Astrophysics (astro-ph.IM), Line (formation), Physics, Sideband, business.industry, Astronomy and Astrophysics, Intensity (physics), [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Space and Planetary Science, Orbit (dynamics), Instrumentation and Methods for Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, business, HIFI, Test data
Abstract: The Heterodyne Instrument for the Far Infrared (HIFI) on board the Herschel Space Observatory is composed of a set of fourteen double sideband mixers. We discuss the general problem of the sideband ratio (SBR) determination and the impact of an imbalanced sideband ratio on the line calibration in double sideband heterodyne receivers. The HIFI SBR is determined from a combination of data taken during pre-launch gas cell tests and in-flight. The results and some of the calibration artefacts discovered in the gas cell test data are presented here along with some examples of how these effects appear in science data taken in orbit., Comment: 21 pages, 10 figues. To be published in special Herschel calibration issue of Experimental Astronomy
Published: 2014

15. Determination of the Hyperfine Structure of N[TINF]2[/TINF]D[TSUP]+[/TSUP]

Author: Thomas G. Phillips, Maryvonne Gerin, John C. Pearson, Evelyne Roueff, and E. Falgarone
Subjects: Physics, Space and Planetary Science, Astronomy and Astrophysics, Atomic physics, Spectral resolution, Spectrum analysis, Quantum, Hyperfine structure, Astrophysics::Galaxy Astrophysics, Spectral line, Line (formation)
Abstract: We present new high spectral resolution observations of the N2D+ J = 2 yields 1 and J = 3 yields 2 as well as N2H+ J = 3 yields 2 lines, towards dense molecular cores. The hyperfine structure of the N2H+ and N2D+ transitions is clearly resolved in these sources, in excellent agreement with quantum mechanical calculations. Optical depths are determined from the observed spectra, leading to D/H values of the order of 10 - 30% for the N2D+/N2H+ system. There are a large number of hyperfine components and in addition to providing satellites they contribute to the broadening and asymmetric shapes of the N2H+ and N2D+ line profiles. It is therefore important to take into account the detailed hyperfine structure of the transitions when deducing astrophysical parameters from observed data.
Published: 2001

16. Deuterated molecules in Orion KL from Herschel/HIFI

Author: Nathan R. Crockett, Justin L. Neill, John C. Pearson, Li-Hong Xu, and Edwin A. Bergin
Subjects: Physics, 010504 meteorology & atmospheric sciences, Molecular cloud, Formaldehyde, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Fractionation, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, 3. Good health, Ammonia, chemistry.chemical_compound, chemistry, Deuterium, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Ridge (meteorology), Isotopologue, Methanol, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We present a comprehensive study of the deuterated molecules detected in the fullband HIFI survey of the Orion KL region. Ammonia, formaldehyde, and methanol and their singly deuterated isotopologues are each detected through numerous transitions in this survey with a wide range in optical depths and excitation conditions. In conjunction with a recent study of the abundance of HDO and H$_2$O in Orion KL, this study yields the best constraints on deuterium fractionation in an interstellar molecular cloud to date. As previous studies have found, both the Hot Core and Compact Ridge regions within Orion KL contain significant abundances of deuterated molecules, suggesting an origin in cold grain mantles. In the Hot Core, we find that ammonia is roughly a factor of 2 more fractionated than water. In the Compact Ridge, meanwhile, we find similar deuterium fractionation in water, formaldehyde, and methanol, with D/H ratios of (2---8) $\times$ $10^{-3}$. The [CH$_2$DOH]/[CH$_3$OD] ratio in the Compact Ridge is found to be $1.2 \pm 0.3$. The Hot Core generally has lower deuterium fractionation than the Compact Ridge, suggesting a slightly warmer origin, or a greater contribution from warm gas phase chemistry., 39 pages, 12 figures. Accepted for publication in ApJ. 3 figure sets are available in their entirety in the online form of the Journal
Published: 2013

17. HERSCHEL/HIFI SPECTRAL MAPPING OF C+, CH+, AND CH IN ORION BN/KL: THE PREVAILING ROLE OF ULTRAVIOLET IRRADIATION IN CH+FORMATION

Author: Maryvonne Gerin, Edwin A. Bergin, Gary J. Melnick, John C. Pearson, Dariusz C. Lis, Volker Ossenkopf-Okada, Harshal Gupta, David A. Neufeld, Zsofia Nagy, Edith Falgarone, Patrick W. Morris, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, Analytical chemistry, FOS: Physical sciences, ISM: clouds, 01 natural sciences, ISM: abundances, Ion, chemistry.chemical_compound, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, astrochemistry, Molecular cloud, Carbon-13, Carbon-12, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Charged particle, Abundance of the chemical elements, ISM: lines and bands, molecular processes, Astrophysics - Solar and Stellar Astrophysics, chemistry, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Carbon monoxide
Abstract: The CH$^+$ ion is a key species in the initial steps of interstellar carbon chemistry. Its formation in diverse environments where it is observed is not well understood, however, because the main production pathway is so endothermic (4280 K) that it is unlikely to proceed at the typical temperatures of molecular clouds. We investigation CH$^+$ formation with the first velocity-resolved spectral mapping of the CH$^+$ $J=1-0, 2-1$ rotational transitions, three sets of CH $\Lambda$-doubled triplet lines, $^{12}$C$^+$ and $^{13}$C$^+$, and CH$_3$OH 835~GHz E-symmetry Q branch transitions, obtained with Herschel/HIFI over $\approx$12 arcmin$^2$ centered on the Orion BN/KL source. We present the spatial morphologies and kinematics, cloud boundary conditions, excitation temperatures, column densities, and $^{12}$C$^+$ optical depths. Emission from C$^+$, CH$^+$, and CH is indicated to arise in the diluted gas, outside of the explosive, dense BN/KL outflow. Our models show that UV-irradiation provides favorable conditions for steady-state production of CH$^+$ in this environment. Surprisingly, no spatial or kinematic correspondences of these species are found with H$_2$ S(1) emission tracing shocked gas in the outflow. We propose that C$^+$ is being consumed by rapid production of CO to explain the lack of C$^+$ and CH$^+$ in the outflow, and that fluorescence provides the reservoir of H$_2$ excited to higher ro-vibrational and rotational levels. Hence, in star-forming environments containing sources of shocks and strong UV radiation, a description of CH$^+$ formation and excitation conditions is incomplete without including the important --- possibly dominant --- role of UV irradiation., Comment: Accepted for publication in The Astrophysical Journal
Published: 2016

18. First detection of gas-phase ammonia in a planet-forming disk

Author: Vachail N. Salinas, Edwin A. Bergin, John C. Pearson, Geoffrey A. Blake, Ewine F. van Dishoeck, Michiel R. Hogerheijde, L. Ilsedore Cleeves, Umut A. Yildiz, Dariusz C. Lis, Lars E. Kristensen, Christian Brinch, Gary J. Melnick, and O. Panić
Subjects: Physics, Solar System, Astrochemistry, 010504 meteorology & atmospheric sciences, chemistry.chemical_element, Astronomy and Astrophysics, Context (language use), Astrophysics, Protoplanetary disk, 01 natural sciences, Nitrogen, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, TW Hydrae, 010303 astronomy & astrophysics, Water vapor, 0105 earth and related environmental sciences, Line (formation)
Abstract: Context. Nitrogen chemistry in protoplanetary disks and the freeze-out on dust particles is key for understanding the formation of nitrogen-bearing species in early solar system analogs. In dense cores, 10% to 20% of the nitrogen reservoir is locked up in ices such as NH_3, NH_4^+ and OCN^−. So far, ammonia has not been detected beyond the snowline in protoplanetary disks. Aims. We aim to find gas-phase ammonia in a protoplanetary disk and characterize its abundance with respect to water vapor. Methods. Using HIFI on the Herschel Space Observatory, we detected for the first time the ground-state rotational emission of ortho-NH_3 in a protoplanetary disk around TW Hya. We used detailed models of the disk’s physical structure and the chemistry of ammonia and water to infer the amounts of gas-phase molecules of these species. We explored two radial distributions (extended across the disk and confined to
Published: 2016

19. Rotational spectra of isotopic species of methyl cyanide, CH3CN, in theirv8= 1 excited vibrational states

Author: Matthias H. Ordu, Frank Lewen, Holger S. P. Müller, Nadine Wehres, Brian J. Drouin, and John C. Pearson
Subjects: Astrochemistry, Cyanide, Analytical chemistry, FOS: Physical sciences, Context (language use), Astrophysics, Kinetic energy, 01 natural sciences, Spectral line, chemistry.chemical_compound, Physics - Chemical Physics, 0103 physical sciences, Molecule, Sagittarius B2, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Chemical Physics (physics.chem-ph), Physics, 010304 chemical physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, chemistry, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Excited state, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Methyl cyanide is an important trace molecule in space, especially in star-forming regions where it is one of the more common molecules used to derive kinetic temperatures. We want to obtain accurate spectroscopic parameters of minor isotopologs of methyl cyanide in their lowest excited $v_8 = 1$ vibrational states to support astronomical observations, in particular, with interferometers such as ALMA. The laboratory rotational spectrum of methyl cyanide in natural isotopic composition has been recorded from the millimeter to the terahertz regions. Transitions with good signal-to-noise ratios could be identified for the three isotopic species CH$_3^{13}$CN, $^{13}$CH$_3$CN, and CH$_3$C(15)N up to about 1.2 THz ($J'' \le 66$). Accurate spectroscopic parameters were obtained for all three species. The present data were already instrumental in identifying $v_8 = 1$ lines of methyl cyanide with one $^{13}$C in IRAM 30 m and ALMA data toward Sagittarius B2(N)., Comment: 6 pages, 1 figure, article appeared; CDMS links and two references updated
Published: 2016

20. Nitrogen hydrides in interstellar gas II. Analysis of Herschel/HIFI observations towards W49N and G10.6-0.4 (W31C)

Author: John H. Black, John C. Pearson, Shanshan Yu, B. Godard, M. De Luca, Audrey Coutens, Maryvonne Gerin, Holger S. P. Müller, Bhaswati Mookerjea, Carina M. Persson, Javier R. Goicoechea, George E. Hassel, E. Herbst, Pierre Hily-Blant, A. O. H. Olofsson, Tom Bell, and Karl M. Menten
Subjects: Physics, Range (particle radiation), Absorption spectroscopy, Hydrogen molecule, Analytical chemistry, chemistry.chemical_element, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Nitrogen, Astrophysics - Astrophysics of Galaxies, Spectral line, Ammonia, chemistry.chemical_compound, chemistry, 13. Climate action, Space and Planetary Science, Abundance (ecology), Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010306 general physics, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics
Abstract: We have used the Herschel-HIFI instrument to observe interstellar nitrogen hydrides along the sight-lines towards W49N and G10.6-0.4 in order to elucidate the production pathways leading to nitrogen-bearing species in diffuse gas. All detections show absorption by foreground material over a wide range of velocities, as well as absorption associated directly with the hot-core source itself. As in the previously published observations towards G10.6-0.4, the NH, NH2 and NH3 spectra towards W49N show strikingly similar and non-saturated absorption features. We decompose the absorption of the foreground material towards W49N into different velocity components in order to investigate whether the relative abundances vary among the velocity components, and, in addition, we re-analyse the absorption lines towards G10.6-0.4 in the same manner. Abundances, with respect to molecular hydrogen, in each velocity component are estimated using CH. The analysis points to a co-existence of the nitrogen hydrides in diffuse or translucent interstellar gas with a high molecular fraction. Towards both sources, we find that NH is always at least as abundant as both o-NH2 and o-NH3, in sharp contrast to previous results for dark clouds. We find relatively constant N(NH)/N(o-NH3) and N(o-NH2)/N(o-NH3) ratios with mean values of 3.2 and 1.9 towards W49N, and 5.4 and 2.2 towards G10.6-0.4, respectively. The mean abundance of o-NH3 is ~2x10^-9 towards both sources. The nitrogen hydrides also show linear correlations with CN and HNC towards both sources, and looser correlations with CH. The upper limits on the NH+ abundance indicate column densities < 2 - 14 % of N(NH). Surprisingly low values of the ammonia ortho-to-para ratio are found in both sources, ~0.5 - 0.7 +- 0.1. This result cannot be explained by current models as we had expected to find a value of unity or higher., 35 pages, 74 figures
Published: 2012
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21. Herschel/HIFI detections of hydrides towards AFGL 2591. Envelope emission versus tenuous cloud absorption [Letter]

Author: Javier R. Goicoechea, M. Tafalla, Pierre Encrenaz, P. Stäuber, Jes K. Jørgensen, Jonathan Braine, T. Giannini, Laurent Pagani, Steven D. Doty, Alain Baudry, Michael Olberg, Rafael Bachiller, M. Marseille, Th. de Graauw, E. F. van Dishoeck, Lars E. Kristensen, R. Schieder, José Cernicharo, André Csillaghy, S. Bruderer, S. F. Wampfler, T. A. van Kempen, Paolo Saraceno, Arnold O. Benz, Gary J. Melnick, David A. Neufeld, T. Jacq, C. Dedes, J. Santiago-Garcia, N. Honingh, John C. Pearson, R. Shipman, Frank Helmich, D. Teyssier, M. Fich, A. Di Giorgio, Willem Jellema, Edwin Bergin, Per Bjerkeli, N. Whyborn, Paola Caselli, R. Plume, Ruud Visser, Dariusz C. Lis, M. Melchior, Fabrice Herpin, Christophe Risacher, B. Larsson, Emmanuel Caux, Brunella Nisini, C. McCoey, Christian Monstein, F. Daniel, Geoffrey A. Blake, Doug Johnstone, Gregory J. Herczeg, Umut A. Yildiz, Berengere Parise, Claudio Codella, Sylvain Bontemps, René Liseau, Milena Benedettini, Michiel R. Hogerheijde, Friedrich Wyrowski, Carsten Dominik, F. F. S. van der Tak, W. Bächtold, Asunción Fuente, Low Energy Astrophysics (API, FNWI), 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), 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), Herschel Science Center [Madrid], European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), 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), 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), 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 Sciences et Technologies - Bordeaux 1 (UB), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), École normale supérieure - Paris (ENS Paris), European Space Agency (ESA)-European Space Agency (ESA), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, 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, and Consiglio Nazionale delle Ricerche (CNR)
Subjects: Photon, FOS: Physical sciences, Astrophysics, 7. Clean energy, Far infrared, CHEMISTRY, EXCITATION, OUTFLOW, Solar and Stellar Astrophysics, Spectral resolution, H2O+, Absorption (electromagnetic radiation), Solar and Stellar Astrophysics (astro-ph.SR), Envelope (waves), QB, STAR-FORMING REGIONS, Physics, stars: formation, SPECTROSCOPY, INTERSTELLAR-MEDIUM, astrochemistry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Diatomic molecule, ISM: molecules, Astrophysics - Solar and Stellar Astrophysics, GL-2591, 13. Climate action, Space and Planetary Science, ABUNDANCE, Outflow, ISM: individual objects: AFGL 2591, Excitation
Abstract: The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution and in multiple transitions. Here, we report deep integrations using HIFI in different lines of hydrides towards the high-mass star forming region AFGL 2591. Detected are CH, CH+, NH, OH+, H2O+, while NH+ and SH+ have not been detected. All molecules except for CH and CH+ are seen in absorption with low excitation temperatures and at velocities different from the systemic velocity of the protostellar envelope. Surprisingly, the CH(JF,P = 3/2_2,- - 1/2_1,+) and CH+(J = 1 - 0, J = 2 - 1) lines are detected in emission at the systemic velocity. We can assign the absorption features to a foreground cloud and an outflow lobe, while the CH and CH+ emission stems from the envelope. The observed abundance and excitation of CH and CH+ can be explained in the scenario of FUV irradiated outflow walls, where a cavity etched out by the outflow allows protostellar FUV photons to irradiate and heat the envelope at larger distances driving the chemical reactions that produce these molecules., Comment: Accepted for publication in Astronomy and Astrophysics (HIFI first results issue)
Published: 2010

22. Herschel observations in the ultracompact HII region Mon R2: Water in dense Photon-dominated regions (PDRs)

Author: Arnold O. Benz, Thomas G. Phillips, John C. Pearson, Antonio Usero, D. Teyssier, F. Boulanger, Volker Ossenkopf, F. F. S. van der Tak, Michel Fich, Andrew I. Harris, K. F. Schuster, S. Bruderer, Peter G. Martin, Yoko Okada, C. Dedes, Olivier Berné, Harold W. Yorke, C. Joblin, Asunción Fuente, C. McCoey, Markus Röllig, S. D. Lord, Juergen Stutzki, T. Klein, P. Pilleri, Maryvonne Gerin, José Cernicharo, David A. Neufeld, F. Le Petit, Jérôme Pety, Robert Simon, M. Akyilmaz, Rolf Güsten, Bhaswati Mookerjea, M. Melchior, Javier R. Goicoechea, A. Lorenzani, Jesús Martín-Pintado, Carsten Kramer, R. Szczerba, Santiago García-Burillo, J. R. Rizzo, M. González-García, Pieter Dieleman, Observatorio Astronómico Nacional (OAN), oan, Univ Toulouse UPS, Ctr Etud Spatiale Rayonnements, F-31062 Toulouse 9, France, Centre Etud Spatiale Rayonnements Toulouse, Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid 28850, Spain, Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid, Instituto de Radio Astronomía Milimétrica, Physikalisches Institut [Köln], Universität zu Köln, 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), Max-Planck-Institut für Radioastronomie (MPIFR), Institute of Astronomy [ETH Zürich], Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), 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), Center for Astrophysics and Space Astronomy [Boulder] (CASA), University of Colorado [Boulder], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), foreign laboratories (FL), CERN [Genève], Observatoire de Paris - Site de Paris (OP), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), European Space Astronomy Centre (ESAC), European Space Agency (ESA), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Astronomy, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, 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), Universität zu Köln = University of Cologne, École normale supérieure - Paris (ENS-PSL), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: HII regions, Photon, ISM: structure, FOS: Physical sciences, Astrophysics, CLOUD CORE, 7. Clean energy, 01 natural sciences, Abundance (ecology), 0103 physical sciences, SAGITTARIUS-B2, OUTFLOW, KINEMATICS, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Line (formation), Envelope (waves), Physics, ISM: kinematics and dynamics, 010308 nuclear & particles physics, MONOCEROS R2, Molecular cloud, Astronomy and Astrophysics, PHOTODISSOCIATION, Plasma, Astrophysics - Astrophysics of Galaxies, ISM: molecules, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), submillimeter: ISM, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Ground state
Abstract: Mon R2, at a distance of 830 pc, is the only ultracompact HII region (UC HII) where the photon-dominated region (PDR) between the ionized gas and the molecular cloud can be resolved with Herschel. HIFI observations of the abundant compounds 13CO, C18O, o-H2-18O, HCO+, CS, CH, and NH have been used to derive the physical and chemical conditions in the PDR, in particular the water abundance. The 13CO, C18O, o-H2-18O, HCO+ and CS observations are well described assuming that the emission is coming from a dense (n=5E6 cm-3, N(H2)>1E22 cm-2) layer of molecular gas around the UC HII. Based on our o-H2-18O observations, we estimate an o-H2O abundance of ~2E-8. This is the average ortho-water abundance in the PDR. Additional H2-18O and/or water lines are required to derive the water abundance profile. A lower density envelope (n~1E5 cm-3, N(H2)=2-5E22 cm-2) is responsible for the absorption in the NH 1_1-0_2 line. The emission of the CH ground state triplet is coming from both regions with a complex and self-absorbed profile in the main component. The radiative transfer modeling shows that the 13CO and HCO+ line profiles are consistent with an expansion of the molecular gas with a velocity law, v_e =0.5 x (r/Rout)^{-1} km/s, although the expansion velocity is poorly constrained by the observations presented here., 4 pages, 5 figures
Published: 2010

23. Detection of interstellar oxidaniumyl: Abundant H2O+ towards the star-forming regions DR21, Sgr B2, and NGC6334

Author: C. Joblin, A. Di Giorgio, Olivier Berné, Sylvie Cabrit, Carsten Dominik, S. Pacheco, Paul F. Goldsmith, Charlotte Vastel, H. W. Yorke, Pieter Dieleman, G. Melnick, S.-L. Quin, F. F. S. van der Tak, M. Salez, Nathan R. Crockett, Sandrine Bottinelli, Andrew I. Harris, Doug Johnstone, Patrick W. Morris, Asunción Fuente, Juergen Stutzki, Frank Helmich, Claudio Codella, Sébastien Maret, David A. Neufeld, P. Saraceno, Neil Trappe, Adam Walters, Jonas Zmuidzinas, Robert Simon, Javier R. Goicoechea, C. McCoey, Tom Bell, Pierre Encrenaz, T. Jacq, M. H. D. van der Wiel, D. C. Lis, Carsten Kramer, Simon Bruderer, Pierre Hily-Blant, R. Plume, J. A. Murphy, F. Boulanger, A. Lorenzani, Karl Jacobs, Peter Schilke, Serena Viti, Mihkel Kama, S. Wang, N. Whyborn, Arnold O. Benz, Alain Baudry, Jesús Martín-Pintado, A. C. A. Boogert, Thomas G. Phillips, Stephan Schlemmer, Peter G. Martin, Martin Emprechtinger, K. Demyk, Milena Benedettini, Rolf Güsten, Edwin A. Bergin, Volker Ossenkopf, R. Rizzo, Audrey Coutens, Paola Caselli, D. Teyssier, Valentine Wakelam, Bhaswati Mookerjea, Shanshan Yu, Thomas F. Giesen, N. Crimier, Emmanuel Caux, Karl Schuster, Brunella Nisini, A. Bacman, C. Leinz, Alain Klotz, Claudia Comito, Markus Röllig, Cecilia Ceccarelli, M. Melchior, William D. Langer, A. G. G. M. Tielens, John C. Pearson, F. Daniel, Maryvonne Gerin, José Cernicharo, Geoffrey A. Blake, Holger S. P. Müller, Bertrand Lefloch, S. D. Lord, T. Klein, Karl M. Menten, Berengere Parise, E. Herbst, Marie-Lise Dubernet, Michel Perault, L. Pagani, Edith Falgarone, Claudine Kahane, Laboratoire Univers et Théories (LUTH (UMR_8102)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), SRON Netherlands Institute for Space Research (SRON), California Institute of Technology (CALTECH), Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany, Univ Cologne, Inst Phys 1, Max Planck Institute for Radio Astronomy, Max-Planck-Institut für Extraterrestrische Physik (MPE), Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, 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), FORMATION STELLAIRE 2010, 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), Institute of Astronomy [ETH Zürich], Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), 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), 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), 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), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Univ Toulouse UPS, Ctr Etud Spatiale Rayonnements, F-31062 Toulouse 9, France, Centre Etud Spatiale Rayonnements Toulouse, CNRS INSU, UMR 5187, F-31028 Toulouse 4, France, UMR 5187 Toulouse, Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid 28850, Spain, Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid, École normale supérieure - Paris (ENS Paris), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Cahill Center for Astronomy and Astrophysics, Laboratoire de Radioastronomie (LRA), 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)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), foreign laboratories (FL), CERN [Genève], Ohio State Univ, Dept Phys, Columbus, OH 43210 USA, Ohio State University [Columbus] (OSU), Ohio State Univ, Dept Astron & Chem, Columbus, OH 43210 USA, Leibniz Institute for Crystal Growth, Leibniz Institute, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7 Canada, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, Max-Planck-Institut für Radioastronomie (MPIFR), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Modélisation Multi-échelles des Combustibles (LM2C), Service d'Etudes de Simulation du Comportement du combustibles (SESC), Département d'Etudes des Combustibles (DEC), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Département d'Etudes des Combustibles (DEC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, KOSMA, I. Physikalisches Institut, Universität zu Köln, CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA, CALTECH, Ctr Infrared Proc & Anal, Pasadena, Osservatorio di Astrofisica di Roma (OAR), Department of Physics and Astronomy [Calgary], University of Calgary, Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Laboratoire de Didactique André Revuz (LDAR (EA_4434)), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université Paris Diderot - Paris 7 (UPD7)-Université d'Artois (UA), AMOR 2010, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Low Energy Astrophysics (API, FNWI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), I. Physikalisches Institut [Köln], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, 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), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Smithsonian Institution-Harvard University [Cambridge], INAF - Osservatorio Astronomico di Roma (OAR), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, 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), Universiteit Leiden, 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), 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), 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), Harvard University-Smithsonian Institution, Infrared Processing and Analysis Center (IPAC), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université d'Artois (UA)-Université Paris Diderot - Paris 7 (UPD7)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Astronomy, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])
Subjects: Experimental Physics, molecular data, Continuum (design consultancy), Rotational transition, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, LASER MAGNETIC-RESONANCE, 01 natural sciences, ISM: clouds, Spectral line, ISM: abundances, 0103 physical sciences, ABSORPTION, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Hyperfine structure, Astrophysics::Galaxy Astrophysics, QB, Line (formation), Physics, Range (particle radiation), SPECTROSCOPY, IDENTIFICATION, 010308 nuclear & particles physics, astrochemistry, NGC-6334, OH, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], COMET-KOHOUTEK, Space and Planetary Science, GROUND-STATE, Astrophysics of Galaxies (astro-ph.GA), Outflow, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], EMISSION, ROTATIONAL SPECTRUM, line: identification
Abstract: We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. The characteristic hyperfine pattern of the H2O+ ground-state rotational transition, and the lack of other known low-energy transitions in this frequency range, identifies the feature as H2O+ absorption against the dust continuum background and allows us to derive the velocity profile of the absorbing gas. By comparing this velocity profile with velocity profiles of other tracers in the DR21 star-forming region, we constrain the frequency of the transition and the conditions for its formation. In DR21, the velocity distribution of H2O+ matches that of the [CII] line at 158\mu\m and of OH cm-wave absorption, both stemming from the hot and dense clump surfaces facing the HII-region and dynamically affected by the blister outflow. Diffuse foreground gas dominates the absorption towards Sgr B2. The integrated intensity of the absorption line allows us to derive lower limits to the H2O+ column density of 7.2e12 cm^-2 in NGC 6334, 2.3e13 cm^-2 in DR21, and 1.1e15 cm^-2 in Sgr B2., Comment: Accepted for publication in A&A
Published: 2010

24. Strong CH^+ J = 1–0 emission and absorption in DR21

Author: A. P. Marston, Benjamin Godard, Peter G. Martin, David A. Neufeld, C. Joblin, Robert Simon, M. Fich, Arnold O. Benz, F. F. S. van der Tak, Rolf Güsten, Thomas G. Phillips, Asunción Fuente, Harold W. Yorke, Juergen Stutzki, Markus Röllig, Willem Jellema, F. Boulanger, S. D. Lord, D. Teyssier, Sylvie Cabrit, T. Klein, Neal A. Erickson, F. Schmülling, M. Salez, Edith Falgarone, Christophe Risacher, Jesús Martín-Pintado, Andrew I. Harris, Maryvonne Gerin, John C. Pearson, Volker Ossenkopf, Pierre Lesaffre, Carsten Kramer, Astronomy, 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), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Physikalisches Institut, Universität zu Köln, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Jet Propulsion Laboratory, California Institute of Technology (JPL), 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), Institute for Astronomy, Department of Physics, ETH Zürich, Observatorio Astronomico Nacional, Madrid, Max-Planck-Institut für Radioastronomie (MPIfR), Department of Astronomy, University of Maryland, Instituto de Radio Astronomía Milimétrica (IRAM), Infrared Processing Analysis Center, California Institute of Technology (IPAC), Department of Astronomy and Astrophysics, University of Toronto, Centro de Astrobiología, Consejo Superior de Investigaciones Científicas (CSIC)/Instituto Nacional de Técnica Aeroespacial (INTA) (CAB), Department of Physics and Astronomy, Johns Hopkins University, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, SRON Netherlands Institute for Space Research, European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Astronomy, University of Massachusetts, and Department of Physics and Astronomy, University of Waterloo
Subjects: Absorption spectroscopy, Analytical chemistry, Rotational transition, LINE, FOS: Physical sciences, Astrophysics, SHOCKS, MOLECULAR OUTFLOW, CHEMISTRY, Emission spectrum, Absorption (electromagnetic radiation), Astrophysics::Galaxy Astrophysics, Line (formation), Physics, ISM: kinematics and dynamics, Turbulent dissipation, Line-of-sight, SPECTROSCOPY, INTERSTELLAR-MEDIUM, astrochemistry, turbulence, DR-21, Astronomy and Astrophysics, PROFILES, Ridge (differential geometry), REGIONS, DIFFUSE CLOUDS, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Falgarone, E. et al., We report the first detection of the ground-state rotational transition of the methylidyne cation CH+ towards the massive star-forming region DR 21 with the HIFI instrument onboard the Herschel satellite. The line profile exhibits a broad emission line, in addition to two deep and broad absorption features associated with the DR 21 molecular ridge and foreground gas. These observations allow us to determine a 12CH+J = 1-0 line frequency of ν = 835 137 ± 3 MHz, in good agreement with a recent experimental determination. We estimate the CH+ column density to be a few 1013 cm-2 in the gas seen in emission, and >1014 cm-2 in the components responsible for the absorption, which is indicative of a high line of sight average abundance [CH+] /[H] > 1.2 × 10-8. We show that the CH + column densities agree well with the predictions of state-of-the-art C-shock models in dense UV-illuminated gas for the emission line, and with those of turbulent dissipation models in diffuse gas for the absorption lines. © 2010 ESO, Part of this work was supported by the German DeutscheFor-schungsgemeinschaft, DFG project #Os177/1–1.
Published: 2010

25. Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C

Author: Benjamin Godard, Jonas Zmuidzinas, T. A. Bell, John H. Black, Frank Maiwald, Martin Emprechtinger, Maryvonne Gerin, C. Joblin, S. Wang, M. Perault, Patrick Hennebelle, Gary J. Melnick, Shanshan Yu, Peter Schilke, S. D. Lord, Paule Sonnentrucker, P. Hily-Blant, D. Johnstone, F. Boulanger, M. R. Schmidt, D. Teyssier, Raquel Monje, Alexandre Karpov, Jacob Kooi, Stephan Schlemmer, M. Salez, Peter G. Martin, David A. Neufeld, P. F. Goldsmith, Neil Trappe, M. De Luca, Karl M. Menten, Robert Kołos, F. F. S. van der Tak, Javier R. Goicoechea, Emmanuel Caux, Sébastien Maret, S.-L. Qin, Thomas R. Geballe, Cecile Gry, Neal R. Erickson, Rene Plume, Harold W. Yorke, Jesús Martín-Pintado, E. Falgarone, J. A. Murphy, Sylvie Cabrit, M. Kaźmierczak, Nathan R. Crockett, Eric Herbst, Jacek Krełowski, Charlotte Vastel, José Cernicharo, Holger S. P. Müller, P. Zaal, John C. Pearson, Carina M. Persson, Patrick W. Morris, Marie-Lise Dubernet, H. Gupta, P. J. Encrenaz, Rudolf Schieder, Fabien Daniel, Audrey Coutens, Adwin Boogert, Geoffrey A. Blake, Cecilia Ceccarelli, Edwin A. Bergin, J. Stutzki, Dariusz C. Lis, Thomas F. Giesen, Emmanuel Dartois, Bhaswati Mookerjea, Thomas G. Phillips, Laurent Pagani, Volker Ossenkopf, C. Comito, 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), 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 Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Astronomy, and Faure, Alexandre
Subjects: Experimental Physics, FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: abundances, COLOGNE DATABASE, OXYGEN, 0103 physical sciences, ABSORPTION, Sagittarius B2, 010306 general physics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, AMMONIA, CDMS, Line-of-sight, SPECTROSCOPY, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astrochemistry, ASTRONOMY, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, molecular processes, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), MOLECULAR CLOUDS, VAPOR, submillimeter: ISM, SUBMILLIMETER
Abstract: We present Herschel/HIFI observations of the fundamental rotational transitions of ortho- and para-H$_2^{16}$O and H$_2^{18}$O in absorption towards Sagittarius~B2(M) and W31C. The ortho/para ratio in water in the foreground clouds on the line of sight towards these bright continuum sources is generally consistent with the statistical high-temperature ratio of 3, within the observational uncertainties. However, somewhat unexpectedly, we derive a low ortho/para ratio of $2.35 \pm 0.35$, corresponding to a spin temperature of $\sim$27~K, towards Sagittarius~B2(M) at velocities of the expanding molecular ring. Water molecules in this region appear to have formed with, or relaxed to, an ortho/para ratio close to the value corresponding to the local temperature of the gas and dust., Accepted for publication in A&A, HIFI Special Issue; 5 pages, 3 figures
Published: 2010

26. Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6-0.4

Author: Robert Kołos, Raquel Monje, Lorene Samoska, John H. Black, Alessandra Contursi, Russ Shipman, Sabine Philipp-May, Javier R. Goicoechea, M. De Luca, Patrick Hennebelle, M. Perault, José Cernicharo, Carina M. Persson, Morvan Salez, David Teyssier, A. Lorenzani, Eric Herbst, Benjamin Godard, Jacek Krełowski, Cecile Gry, Stephan Schlemmer, Audrey Coutens, Thomas F. Giesen, Jonas Zmuidzinas, Rene Plume, John C. Pearson, Mirisloaw Schmidt, Paul F. Goldsmith, Francois Boulanger, Paul B. Rimmer, Karl M. Menten, Jesús Martín-Pintado, T. A. Bell, Harshal Gupta, Pierre Hily-Blant, Jürgen Stutzki, Maryvonne Gerin, Thomas G. Phillips, K. Klein, Charlotte Vastel, Maja Kazmierczak, D. C. Lis, Pierre Encrenaz, Christine Joblin, Thomas R. Geballe, Emmanuel Dartois, Bhaswati Mookerjea, Alain Cros, Paule Sonnentrucker, Alexander G. G. M. Tielens, David A. Neufeld, Edith Falgarone, Shanshan Yu, 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), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Department of Physics (OHIO STATE UNIVERSITY), Ohio State University [Columbus] (OSU), Departments of Astronomy and Chemistry, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), CalTech-CSO (CSO), California Institute of Technology (CALTECH), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), 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), 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), I. Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, 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), 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), Torun Centre for Astronomy (TCfA), Nicolaus Copernicus University [Toruń], Institute of physical chemistry, Polska Akademia Nauk = Polish Academy of Sciences (PAN), Instituto de Estructura de la Materia (IEM), Tata Institute for Fundamental Research (TIFR), Department of Physics and Astronomy [Calgary], University of Calgary, Copernicus Astronomical Center of the Polish Academy of Sciences (CAMK), Polish Academy of Sciences (PAN), Max-Planck-Institut für Extraterrestrische Physik (MPE), Max-Planck-Institut für Radioastronomie (MPIFR), Gemini Telescope, SRON Netherlands Institute for Space Research (SRON), Sterrewacht Leiden, Universiteit Leiden, Deutsches Zentrum für Luft- und Raumfahrt [Bonn] (DLR), Laboratoire Lasers, Plasmas et Procédés photoniques (LP3), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), PRISMAS, European Project, Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Dynamique des milieux interstellaires et plasmas stellaires, Chalmers University of Technology, Centro de Astrobiología, Consejo Superior de Investigaciones Científicas (CSIC)/Instituto Nacional de Técnica Aeroespacial (INTA) (CAB), Departments of Physics, Astronomy and Chemistry, Ohio State University, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Jet Propulsion Laboratory, California Institute of Technology (JPL), Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Université de Toulouse (UT), Laboratoire de Physique Théorique (LPT), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Physikalisches Institut, Universität zu Köln, Institute of Physical Chemistry, Polish Academy of Sciences, Tata Institute of Fundamental Research (TIFR), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Extraterrestriche Physik (MPE), Max-Planck-Institut für Radioastronomie (MPIfR), Gemini telescope, Hilo, Centrum Astronomiczne im. M. Kopernika, Warszawa (CAMK), SRON Netherlands Institute for Space Research, Sterrewacht Leiden, Leiden University, Deutsches Zentrum für Luft- und Raumfahrt (DLR), INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA), École normale supérieure - Paris (ENS Paris), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, Universität zu Köln, Universiteit Leiden [Leiden], and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)
Subjects: Hydrogen, Absorption spectroscopy, Opacity, chemistry.chemical_element, FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, Ion, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, Line-of-sight, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], chemistry, 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], Atomic physics, Ground state, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We report the detection of absorption lines by the reactive ions OH+, H2O+and H3O+ along the line of sight to the submillimeter continuum source G10.6-0.4 (W31C). We used the Herschel HIFI instrument in dual beam switch mode to observe the ground state rotational transitions of OH+ at 971 GHz, H2O+ at 1115 and 607 GHz, and H3O+ at 984 GHz. The resultant spectra show deep absorption over a broad velocity range that originates in the interstellar matter along the line of sight to G10.6-0.4 as well as in the molecular gas directly associated with that source. The OH+ spectrum reaches saturation over most velocities corresponding to the foreground gas, while the opacity of the H2O+ lines remains lower than 1 in the same velocity range, and the H3O+line shows only weak absorption. For LSR velocities between 7 and 50 km s-1 we estimate total column densities of N(OH+) >= 2.5 × 1014 cm-2, N(H2O+) ~6 × 1013 cm-2 and N(H3O+) ~4.0 × 1013 cm-2. These detections confirm the role of O+ and OH+ in initiating the oxygen chemistry in diffuse molecular gas and strengthen our understanding of the gas phase production of water. The high ratio of the OH+ by the H2O+ column density implies that these species predominantly trace low-density gas with a small fraction of hydrogen in molecular form.
Published: 2010
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27. Herschel observations of EXtra-Ordinary Sources (HEXOS): Observations of H2O and its isotopologues towards Orion KL

Author: Pierre Encrenaz, Doug Johnstone, S. D. Lord, Volker Tolls, Edith Falgarone, John C. Pearson, Marie-Lise Dubernet, Michel Perault, D. C. Lis, Javier R. Goicoechea, Geoffrey A. Blake, William D. Langer, Laurent Pagani, Shanshan Yu, Edwin Bergin, S.-L. Qin, Gary J. Melnick, C. Joblin, Volker Ossenkopf, David A. Neufeld, Thomas F. Giesen, Peter G. Martin, Charlotte Vastel, Patrick W. Morris, J. A. Murphy, Martin Emprechtinger, Neil Trappe, W. D. Latter, Nathan R. Crockett, Paul F. Goldsmith, Harold W. Yorke, M. Salez, Sébastien Maret, Peter Schilke, Stephan Schlemmer, S. Wang, Jonas Zmuidzinas, Maryvonne Gerin, F. F. S. van der Tak, José Cernicharo, Holger S. P. Müller, R. Plume, F. Daniel, Juergen Stutzki, Tom Bell, Emmanuel Caux, Karl M. Menten, Cecilia Ceccarelli, Thomas G. Phillips, E. Herbst, Sylvie Cabrit, Claudia Comito, Astronomy, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, California Institute of Technology (CALTECH), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), 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-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), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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 Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), CNRS INSU, UMR 5187, F-31028 Toulouse 4, France, UMR 5187 Toulouse, 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), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Max Planck Institute for Radio Astronomy, Université Paris sciences et lettres (PSL), Cahill Center for Astronomy and Astrophysics, Laboratoire de Radioastronomie (LRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), 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), Ohio State Univ, Dept Phys, Columbus, OH 43210 USA, Ohio State University [Columbus] (OSU), Ohio State Univ, Dept Astron & Chem, Columbus, OH 43210 USA, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7 Canada, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, Laboratoire de Modélisation Multi-échelles des Combustibles (LM2C), Service d'Etudes de Simulation du Comportement du combustibles (SESC), Département d'Etudes des Combustibles (DEC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Département d'Etudes des Combustibles (DEC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max-Planck-Institut für Radioastronomie (MPIFR), Infrared Processing and Analysis Center (IPAC), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), foreign laboratories (FL), CERN [Genève], Department of Physics and Astronomy [Calgary], University of Calgary, I. Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, Laboratoire de Didactique André Revuz (LDAR (EA_4434)), Université d'Artois (UA)-Université Paris Diderot - Paris 7 (UPD7)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Harvard University-Smithsonian Institution, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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), École normale supérieure - Paris (ENS Paris), Univ Toulouse UPS, Ctr Etud Spatiale Rayonnements, F-31062 Toulouse 9, France, Centre Etud Spatiale Rayonnements Toulouse, 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), CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA, CALTECH, Ctr Infrared Proc & Anal, Pasadena, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Universität zu Köln, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université Paris Diderot - Paris 7 (UPD7)-Université d'Artois (UA), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), 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), Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid 28850, Spain, Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid, 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), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction de l'Energie Nucléaire (CEA-DEN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany, and Univ Cologne, Inst Phys 1
Subjects: Opacity, Experimental Physics, FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: abundances, Abundance (ecology), 0103 physical sciences, Isotopologue, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Line (formation), Physics, geography, Line-of-sight, Plateau, geography.geographical_feature_category, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Sublimation (phase transition), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
Abstract: We report the detection of more than 48 velocity-resolved ground rotational state transitions of H2(16)O, H2(18)O, and H2(17)O - most for the first time - in both emission and absorption toward Orion KL using Herschel/HIFI. We show that a simple fit, constrained to match the known emission and absorption components along the line of sight, is in excellent agreement with the spectral profiles of all the water lines. Using the measured H2(18)O line fluxes, which are less affected by line opacity than their H2(16)O counterparts, and an escape probability method, the column densities of H2(18)O associated with each emission component are derived. We infer total water abundances of 7.4E-5, 1.0E-5, and 1.6E-5 for the plateau, hot core, and extended warm gas, respectively. In the case of the plateau, this value is consistent with previous measures of the Orion-KL water abundance as well as those of other molecular outflows. In the case of the hot core and extended warm gas, these values are somewhat higher than water abundances derived for other quiescent clouds, suggesting that these regions are likely experiencing enhanced water-ice sublimation from (and reduced freeze-out onto) grain surfaces due to the warmer dust in these sources., Comment: 5 pages, 2 figures
Published: 2010
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28. Strong absorption by interstellar hydrogen fluoride: Herschel/HIFI observations of the sight-line to G10.6-0.4 (W31C)

Author: M. De Luca, Bhaswati Mookerjea, Charlotte Vastel, René Liseau, E. Herbst, Pierre Encrenaz, C. Joblin, Javier R. Goicoechea, Jesús Martín-Pintado, Juergen Stutzki, Patrick W. Morris, P. Cais, David A. Neufeld, Paul F. Goldsmith, Maryvonne Gerin, Stephan Schlemmer, Mark B. Schmidt, José Cernicharo, Shanshan Yu, M. Kazmierczak, P. Planesas, D. Teyssier, Edith Falgarone, M. Salez, Patrick Hennebelle, Harshal Gupta, Robert Kołos, Audrey Coutens, Emmanuel Caux, John C. Pearson, F. Boulanger, Karl M. Menten, Michel Perault, Paule Sonnentrucker, John H. Black, Emmanuel Dartois, Tom Bell, B. Godard, Jacek Krełowski, Raquel Monje, Thomas R. Geballe, Carina M. Persson, Pierre Hily-Blant, Thomas G. Phillips, Cecile Gry, R. Plume, Dariusz C. Lis, Thomas F. Giesen, 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), California Institute of Technology (CALTECH), 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), Laboratoire de Radioastronomie (LRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), 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), 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), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Indian Institute of Technology Delhi (IIT Delhi), Ohio State University [Columbus] (OSU), 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), Max-Planck-Institut für Radioastronomie (MPIFR), KOSMA, I. Physikalisches Institut, Universität zu Köln = University of Cologne, Department of Materials Science and Engineering, KTH (KTH), Department of Materials Science and Engineering, KTH, Department of Obstetrics and Gynecology, J. Gutenberg-University, Herschel Science Center [Madrid], European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), 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), 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 Sciences et Technologies - Bordeaux 1 (UB), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), École normale supérieure - Paris (ENS Paris), 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), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, Universität zu Köln, European Space Agency (ESA)-European Space Agency (ESA), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1
Subjects: Exothermic reaction, Hydrogen, chemistry.chemical_element, FOS: Physical sciences, Astrophysics, 7. Clean energy, 01 natural sciences, Dual beam, chemistry.chemical_compound, 0103 physical sciences, Thermochemistry, 010306 general physics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, Sideband, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Hydrogen fluoride, Astrophysics - Astrophysics of Galaxies, ISM: molecules, molecular processes, Sight line, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Fluorine, submillimeter: ISM, Atomic physics
Abstract: We report the detection of strong absorption by interstellar hydrogen fluoride along the sight-line to the submillimeter continuum source G10.6-0.4 (W31C). We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 1232.4763 GHz J=1-0 HF transition in the upper sideband of the Band 5a receiver. The resultant spectrum shows weak HF emission from G10.6-0.4 at LSR velocities in the range -10 to -3 km/s, accompanied by strong absorption by foreground material at LSR velocities in the range 15 to 50 km/s. The spectrum is similar to that of the 1113.3430 GHz 1(11)-0(00) transition of para-water, although at some frequencies the HF (hydrogen fluoride) optical depth clearly exceeds that of para-H2O. The optically-thick HF absorption that we have observed places a conservative lower limit of 1.6E+14 cm-2 on the HF column density along the sight-line to G10.6-0.4. Our lower limit on the HF abundance, 6E-9 relative to hydrogen nuclei, implies that hydrogen fluoride accounts for between ~ 30 and 100% of the fluorine nuclei in the gas phase along this sight-line. This observation corroborates theoretical predictions that - because the unique thermochemistry of fluorine permits the exothermic reaction of F atoms with molecular hydrogen - HF will be the dominant reservoir of interstellar fluorine under a wide range of conditions., Comment: Accepted for publication in Astronomy and Astrophysics (Herschel special issue). This revised version corrects a typographic error in the HTML abstract, in which the lower limit on the HF abundance (should be 6E-9) was previously misstated. The abstract in the PDF version is correct and the latter has not been modified
Published: 2010
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29. Herschel/HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region

Author: Fabrice Herpin, José Cernicharo, Carsten Dominik, A. Di Giorgio, T. Jacq, Pierre Encrenaz, Doug Johnstone, Claudio Codella, Steven D. Doty, M. Fich, F. F. S. van der Tak, Jes K. Jørgensen, Gregory J. Herczeg, Volker Ossenkopf, Paola Caselli, S. F. Wampfler, M. Marseille, Edwin Bergin, Per Bjerkeli, T. A. van Kempen, Michiel R. Hogerheijde, Sylvain Bontemps, Jonathan Braine, Alain Baudry, Asunción Fuente, Juergen Stutzki, J. Santiago-Garcia, E. Deul, Ruud Visser, Willem Jellema, René Liseau, Javier R. Goicoechea, Paolo Saraceno, Christophe Risacher, Umut A. Yildiz, David A. Neufeld, Berengere Parise, Milena Benedettini, Pieter Dieleman, Frank Helmich, E. F. van Dishoeck, R. Schieder, John C. Pearson, Dariusz C. Lis, Lars E. Kristensen, F.-C. Liu, T. Giannini, Arnold O. Benz, F. Daniel, Friedrich Wyrowski, Rafael Bachiller, Geoffrey A. Blake, Russel Shipman, Alexander G. G. M. Tielens, Th. de Graauw, Michael Olberg, Gary J. Melnick, C. McCoey, B. Larsson, Brunella Nisini, R. Plume, M. Tafalla, Simon Bruderer, 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), 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), 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), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), 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), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), Astronomy, 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), École normale supérieure - Paris (ENS-PSL), 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), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and Low Energy Astrophysics (API, FNWI)
Subjects: 010504 meteorology & atmospheric sciences, Astronomy, Evaporation, FOS: Physical sciences, DUST, Astrophysics, Star (graph theory), 01 natural sciences, DENSE CORES, 0103 physical sciences, Radiative transfer, Protostar, WATER, Solar and Stellar Astrophysics, Isotopologue, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences, Envelope (waves), Line (formation), Physics, stars: formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], astrochemistry, NGC-1333 IRAS-4, PROTOSTARS, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], H2CO, ISM: molecules, EVOLUTION, ENVELOPES, ISM: jets and outflows, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, ABUNDANCE, Low Mass, HIFI
Abstract: Herschel-HIFI observations of high-J lines (up to J_u=10) of 12CO, 13CO and C18O are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS 4B, obtained as part of the Water In Star-forming regions with Herschel (WISH) key program. The spectrally-resolved HIFI data are complemented by ground-based observations of lower-J CO and isotopologue lines. The 12CO 10-9 profiles are dominated by broad (FWHM 25-30 km s^-1) emission. Radiative transfer models are used to constrain the temperature of this shocked gas to 100-200 K. Several CO and 13CO line profiles also reveal a medium-broad component (FWHM 5-10 km s^-1), seen prominently in H2O lines. Column densities for both components are presented, providing a reference for determining abundances of other molecules in the same gas. The narrow C18O 9-8 lines probe the warmer part of the quiescent envelope. Their intensities require a jump in the CO abundance at an evaporation temperature around 25 K, thus providing new direct evidence for a CO ice evaporation zone around low-mass protostars., Comment: 8 pages, 9 figures
Published: 2010

30. Origin of the hot gas in low-mass protostars: Herschel-PACS spectroscopy of HH 46

Author: T. Giannini, Patrick W. Morris, R. Shipman, Javier R. Goicoechea, A. Di Giorgio, Michael J. Kaufman, S. F. Wampfler, Sylvain Bontemps, René Liseau, Simon Bruderer, Ruud Visser, Fabrice Herpin, Mario Tafalla, R. H. Lin, Rafael Bachiller, F. F. S. van der Tak, Rene Plume, P. Saraceno, Christophe Risacher, Michel Fich, M. Marseille, Asunción Fuente, Arnold O. Benz, T. Jacq, Pierre Encrenaz, Th. de Graauw, Gregory J. Herczeg, T. A. van Kempen, Jes K. Jørgensen, Steven D. Doty, John C. Pearson, John Anthony Murphy, Jonathan Braine, E. F. van Dishoeck, Umut A. Yildiz, Neil Trappe, Doug Johnstone, Berengere Parise, Edwin Bergin, Per Bjerkeli, G. Melnick, S. Glenz, M. Benedettini, Christian Brinch, C. McCoey, Frank Helmich, R. Huisman, M. Ciechanowicz, F. Daniel, B. Larsson, Friedrich Wyrowski, Geoffrey A. Blake, Brunella Nisini, José Cernicharo, Alain Baudry, David A. Neufeld, Dariusz C. Lis, Michael Olberg, L. Dubbeldam, Lars E. Kristensen, J. Santiago-Garcia, Claudio Codella, Carsten Dominik, Paola Caselli, Michiel R. Hogerheijde, Low Energy Astrophysics (API, FNWI), 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), 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 Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), 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), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), 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), Harvard University-Smithsonian Institution, École normale supérieure - Paris (ENS-PSL), 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), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and Kapteyn Astronomical Institute
Subjects: Experimental Physics, Young stellar object, FOS: Physical sciences, Astrophysics, I, 01 natural sciences, Luminosity, 0103 physical sciences, Protostar, WATER, Solar and Stellar Astrophysics, OUTFLOW, 14. Life underwater, Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Envelope (waves), QB, Physics, stars: formation, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], astrochemistry, Astronomy and Astrophysics, HH-46/47, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ISM: molecules, ISM: jets and outflows, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, ISM: individual objects: HH 46, JETS, SHOCK, Outflow, Low Mass, EMISSION
Abstract: 'Water in Star-forming regions with Herschel' (WISH) is a Herschel Key Programme aimed at understanding the physical and chemical structure of young stellar objects (YSOs) with a focus on water and related species. The low-mass protostar HH 46 was observed with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory to measure emission in H2O, CO, OH, [OI], and [CII] lines located between 63 and 186 um. The excitation and spatial distribution of emission can disentangle the different heating mechanisms of YSOs, with better spatial resolution and sensitivity than previously possible. Far-IR line emission is detected at the position of the protostar and along the outflow axis. The OH emission is concentrated at the central position, CO emission is bright at the central position and along the outflow, and H2O emission is concentrated in the outflow. In addition, [OI] emission is seen in low-velocity gas, assumed to be related to the envelope, and is also seen shifted up to 170 km/s in both the red- and blue-shifted jets. Envelope models are constructed based on previous observational constraints. They indicate that passive heating of a spherical envelope by the protostellar luminosity cannot explain the high-excitation molecular gas detected with PACS, including CO lines with upper levels at >2500 K above the ground state. Instead, warm CO and H2O emission is probably produced in the walls of an outflow-carved cavity in the envelope, which are heated by UV photons and non-dissociative C-type shocks. The bright OH and [OI] emission is attributed to J-type shocks in dense gas close to the protostar. In the scenario described here, the combined cooling by far-IR lines within the central spatial pixel is estimated to be 2 \times 10-2 L_sun, with 60-80% attributed to J- and C-type shocks produced by interactions between the jet and the envelope., Accepted for publication in Astronomy and Astrophysics (Herschel special issue)
Published: 2010

31. Variations in H2O+/H2O ratios toward massive star-forming regions

Author: Carsten Dominik, Michiel R. Hogerheijde, Doug Johnstone, Claudio Codella, Steven D. Doty, Michael Olberg, Th. de Graauw, Rafael Bachiller, M. Marseille, Christophe Risacher, Gary J. Melnick, Pierre Encrenaz, Russel Shipman, J. Santiago, Javier R. Goicoechea, R. Plume, Jes K. Jørgensen, M. Benedettini, T. Jacq, Geoffrey A. Blake, S. F. Wampfler, Lars E. Kristensen, Jonathan Braine, Wilfred Frieswijk, Gregory J. Herczeg, Frank Helmich, Maryvonne Gerin, T. Giannini, Pieter R. Roelfsema, Umut A. Yildiz, Berengere Parise, Pieter Dieleman, A. Di Giorgio, Simon Bruderer, John H. Black, de A Jonge, M. Fich, D. C. Lis, John C. Pearson, Edwin Bergin, L. Chavarria, Per Bjerkeli, T. A. van Kempen, Friedrich Wyrowski, Paolo Saraceno, Fabrice Herpin, M. Tafalla, F. F. S. van der Tak, Sylvain Bontemps, René Liseau, José Cernicharo, E. Falgarone, D. A. Beintema, Asunción Fuente, Juergen Stutzki, F. Daniel, Ruud Visser, Volker Ossenkopf, Paola Caselli, Arnold O. Benz, N. Whyborn, Alain Baudry, E. F. van Dishoeck, C. McCoey, B. Larsson, Brunella Nisini, Low Energy Astrophysics (API, FNWI), Max-Planck-Institut für Radioastronomie (MPIFR), 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), 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), 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), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), 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), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Laboratoire de Radioastronomie (LRA), 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), 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), École normale supérieure - Paris (ENS-PSL), 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), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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), and Astronomy
Subjects: FOS: Physical sciences, LINE, Astrophysics, LASER MAGNETIC-RESONANCE, Star (graph theory), ISM: clouds, 01 natural sciences, CHEMISTRY, 0103 physical sciences, Cluster (physics), Protostar, 010306 general physics, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, QB, Physics, stars: formation, Line-of-sight, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], DR21, ASTRONOMY, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, ISM: molecules, W51, Interstellar medium, Stars, Early results, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SIGHT, submillimeter: ISM, HIFI, Galaxy Astrophysics
Abstract: Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2O and H2O+ lines at 1113.3 and 1115.2 GHz using the Herschel Space Observatory toward a sample of high-mass star-forming regions to observationally study the relation between H2O and H2O+ . Nine out of ten sources show absorption from H2O+ in a range of environments: the molecular clumps surrounding the forming and newly formed massive stars, bright high-velocity outflows associated with the massive protostars, and unrelated low-density clouds along the line of sight. Column densities per velocity component of H2 O+ are found in the range of 10^12 to a few 10^13 cm-2 . The highest N(H2O+) column densities are found in the outflows of the sources. The ratios of H2O+/H2O are determined in a range from 0.01 to a few and are found to differ strongly between the observed environments with much lower ratios in the massive (proto)cluster envelopes (0.01-0.1) than in outflows and diffuse clouds. Remarkably, even for source components detected in H2O in emission, H2O+ is still seen in absorption., Comment: 5 pages, 4 figures, accepted for publication as a letter in the A&A Herschel-HIFI special issue
Published: 2010

32. Rotational spectra of isotopic species of methyl cyanide, CH$_3$CN, in their ground vibrational states up to terahertz frequencies

Author: Brian J. Drouin, John C. Pearson, and Holger S. P. Müller
Subjects: Physics, Chemical Physics (physics.chem-ph), Terahertz radiation, Cyanide, Analytical chemistry, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Quantum number, Kinetic energy, Astrophysics - Astrophysics of Galaxies, Spectral line, Radio spectrum, Radio telescope, chemistry.chemical_compound, chemistry, Space and Planetary Science, Physics - Chemical Physics, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract: Methyl cyanide is an important trace molecule in star-forming regions. It is one of the more common molecules used to derive kinetic temperatures in such sources. As preparatory work for Herschel, SOFIA, and in particular ALMA we want to improve the rest frequencies of the main as well as minor isotopologs of methyl cyanide. The laboratory rotational spectrum of methyl cyanide in natural isotopic composition has been recorded up to 1.63 THz. Transitions with good signal-to-noise ratio could be identified for CH$_3$CN, $^{13}$CH$_3$CN, CH$_3^{13}$CN, CH$_3$C$^{15}$N, CH$_2$DCN, and $^{13}$CH$_3^{13}$CN in their ground vibrational states up to about 1.2 THz. The main isotopic species could be identified even in the highest frequency spectral recordings around 1.6 THz. The highest $J'$ quantum numbers included in the fit are 64 for $^{13}$CH$_3^{13}$CN and 89 for the main isotopic species. Greatly improved spectroscopic parameters have been obtained by fitting the present data together with previously reported transition frequencies. The present data will be helpful to identify isotopologs of methyl cyanide in the higher frequency bands of instruments such as the recently launched Herschel satellite, the upcoming airplane mission SOFIA or the radio telescope array ALMA., Comment: 13 pages, 2 figures, article appeared; CDMS links updated
Published: 2009
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33. Submillimeter Spectrum of Formic Acid

Author: Adam Walters, Brian J. Drouin, Valerio Lattanzi, and John C. Pearson
Subjects: Physics, Formic acid, Terahertz radiation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astronomical spectroscopy, Isotopomers, chemistry.chemical_compound, Quality (physics), chemistry, Deuterium, Space and Planetary Science, Isotopologue
Abstract: We have measured new submillimeter-wave data around 600 GHz and around 1.1 THz for the 13C isotopologue of formic acid and for the two deuterium isotopomers; in each case for both the trans and cis rotamer. For cis-DCOOH and cis-HCOOD in particular only data up to 50 GHz was previously available. For all species the quality and quantity of molecular parameters has been increased providing new measured frequencies and more precise and reliable frequencies in the range of existing and near-future submillimeter and far-infrared astronomical spectroscopy instruments such as Herschel, SOFIA and ALMA.
Published: 2008

34. First Detection of 13CH+ (J=1-0)

Author: Edith Falgarone, John C. Pearson, Thomas G. Phillips, 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), Division of Physics, Mathematics and Astronomy, California Institute of Technology, and Jet Propulsion Laboratory, California Institute of Technology (JPL)
Subjects: Physics, Astrochemistry, Space and Planetary Science, Continuum (design consultancy), Low-ionization nuclear emission-line region, Astronomy and Astrophysics, Astrophysics, Absorption (electromagnetic radiation), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract: International audience; We report the probable detection of the 13CH+ (1-0) line in absorption against the dust continuum emission of a bright star-forming region, G10.6-0.4. If the 13CH+ line velocity centroid is that of the H I gas seen in absorption, the rest frequency we determine is 830.132(3) GHz. This is to be compared to the value of 830.131 GHz derived from new direct spectroscopy laboratory measurements of 12CH+ (1-0) and scaling from 12CH+ (1-0) to 13CH+ (1-0). However, if the 13CH+ line originated in either the star-forming region or in the intervening molecular gas as traced by 12CO (1-0) emission, then the inferred rest frequency would be 830.107(1) or 830.193(4) GHz, respectively, both clearly out of the predicted range. We thus conclude that the 13CH+ line arises in a gas phase not traced by the 12CO (1-0) line but one containing a large column density of cold H I and rich enough in H2 to form CH+. Such properties are those of the cold neutral medium. The inferred column density is N(13CH+)=(2.2+/-0.4)×1012 cm-2, corresponding to N(CH+)=(8.8+/-1.7)×1013 cm-2 for an isotopic abundance ratio [12CH+]/[13CH+]=40. With some assumptions concerning the H2 content of the atomic gas, we estimate the total hydrogen column density in this velocity range and find a CH+ abundance relative to H about twice that in the solar neighborhood, as derived from optical absorption lines.
Published: 2005

35. TERAHERTZ MEASUREMENTS OF THE HOT HYDRONIUM ION WITH AN EXTENDED NEGATIVE GLOW DISCHARGE

Author: John C. Pearson and Shanshan Yu
Subjects: Physics, Absorption spectroscopy, Hydrogen, Terahertz radiation, chemistry.chemical_element, Astronomy and Astrophysics, Ion, chemistry, Space and Planetary Science, Excited state, Molecule, Sagittarius B2, Atomic physics, Spectroscopy
Abstract: Terahertz absorption spectroscopy was employed to detect the ground-state inversion transitions of the hydronium ion (H{sub 3}O{sup +}). The highly excited ions were created with an extended negative glow discharge through a gas mixture of 1 mtorr of H{sub 2}O, 2 mtorr of H{sub 2}, and 12 mtorr of Ar, which allowed observation of transitions with J and K up to 12. In total, 47 transitions were measured in the 0.9-2.0 THz region and 22 of these were observed for the first time. The experimental uncertainties range from 100 to 300 kHz, which are much better than the range 0.3-1.2 MHz reported in previous work. Differences of up to 25.6 MHz were found between the observed positions and the catalog values that have been used for Herschel data analysis of observations of Sagittarius B2(N), NGC 4418, and Arp 220. The new and improved measurements were fit to experimental accuracies with an updated Hamiltonian, and better H{sub 3}O{sup +} predictions are reported to support the proper analysis of astronomical observations by high-resolution spectroscopy telescopes, such as Herschel, SOFIA, and ALMA.
Published: 2014

36. THE ROTATIONAL SPECTRUM OF HCl +

Author: Brian J. Drouin, Harshal Gupta, and John C. Pearson
Subjects: Physics, Coupling constant, Astrochemistry, Astronomy and Astrophysics, Lambda, symbols.namesake, Radical ion, Space and Planetary Science, Isotopic shift, symbols, Emission spectrum, Atomic physics, Hamiltonian (quantum mechanics), Hyperfine structure
Abstract: The rotational spectrum of the radical ion HCl{sup +} has been detected at high resolution in the laboratory, confirming the identification reported in the accompanying Letter by De Luca et al., in diffuse clouds toward W31C and W49N. Three rotational transitions, one in the ground-state {sup 2}{Pi}{sub 3/2} ladder and two in the {sup 2}{Pi}{sub 1/2} ladder (643 cm{sup -1} above ground), were observed in a microwave discharge of He and HCl. Well-resolved chlorine hyperfine structure and {Lambda}-doubling, and the detection of lines of H{sup 37}Cl{sup +} at precisely the expected isotopic shift, provide conclusive evidence for the laboratory identification. Detection of rotational transitions in the {sup 2}{Pi}{sub 1/2} ladder of HCl{sup +} for the first time allows an experimental determination of the individual hyperfine coupling constants of chlorine and yields a precise value of eQq{sub 2}. The spectroscopic constants obtained by fitting a Hamiltonian simultaneously to our data and more than 8000 optical transitions are so precise that they allow us to calculate the frequencies of the {sup 2}{Pi}{sub 3/2} J = 5/2 - 3/2 transition observed in space to within 0.2 km s{sup -1}, and indeed, those of the strongest rotational transitions below 7.5 THz, to better thanmore » 1 km s{sup -1}.« less
Published: 2012

37. Water vapor toward starless cores: The Herschel view

Author: Doug Johnstone, Steven D. Doty, Per Bjerkeli, Pierre Encrenaz, Dominicus Kester, F. Daniel, Jes K. Jørgensen, F. F. S. van der Tak, M. Marseille, Asunción Fuente, Geoffrey A. Blake, Christophe Risacher, A. Megej, Hamid Javadi, Javier R. Goicoechea, Jonathan Braine, J. Santiago-Garcia, John C. Pearson, Fabrice Herpin, Dariusz C. Lis, Arnold O. Benz, T. A. van Kempen, David A. Neufeld, Carsten Dominik, P. Siegel, T. Jacq, Simon Bruderer, Gregory J. Herczeg, T. Giannini, Umut A. Yildiz, Berengere Parise, Michiel R. Hogerheijde, Friedrich Wyrowski, E. F. van Dishoeck, P. Saraceno, Th. de Graauw, W. Luinge, Eric Keto, Sylvain Bontemps, René Liseau, José Cernicharo, A. Di Giorgio, Milena Benedettini, C. Codella, Ruud Visser, Lars E. Kristensen, C. McCoey, B. Larsson, Rafael Bachiller, Russel Shipman, Brunella Nisini, Brian Jackson, Gary J. Melnick, Alain Baudry, S. F. Wampfler, M. Tafalla, Paola Caselli, W. M. Laauwen, Todd Gaier, M. Fich, Edwin A. Bergin, Yuri Aikawa, R. Plume, Laurent Pagani, Michael Olberg, Frank Helmich, Kapteyn Astronomical Institute, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), 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), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], INAF - Osservatorio Astronomico di Roma (OAR), 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), 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), 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), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), SRON Netherlands Institute for Space Research (SRON), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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, ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), Low Energy Astrophysics (API, FNWI), École normale supérieure - Paris (ENS-PSL), Harvard University-Smithsonian Institution, 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), 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), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: Astronomy, FOS: Physical sciences, Astrophysics, INITIAL CONDITIONS, 7. Clean energy, ISM: clouds, OXYGEN, Gas phase, PRESTELLAR CORES, Radiative transfer, TEMPERATURE, Physics, stars: formation, DENSE INTERSTELLAR CLOUDS, Research Programm of Institute for Mathematics, Astrophysics and Particle Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], astrochemistry, Molecular cloud, Photodissociation, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, MOLECULAR-IONS, molecular processes, L1544, 13. Climate action, Space and Planetary Science, radiative transfer, Astrophysics of Galaxies (astro-ph.GA), ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, PRE-STELLAR CORES, ABUNDANCE, line: formation, DEPLETION, Water vapor, Galaxy Astrophysics
Abstract: SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) < 7x10^-9). We investigate the chemistry of water vapor in starless cores beyond the previous upper limits using the highly improved angular resolution and sensitivity of Herschel and measure the abundance of water vapor during evolutionary stages just preceding star formation. High spectral resolution observations of the fundamental ortho water (o-H2O) transition (557 GHz) were carried out with Herschel HIFI toward two starless cores: B68, a Bok globule, and L1544, a prestellar core embedded in the Taurus molecular cloud complex. The rms in the brightness temperature measured for the B68 and L1544 spectra is 2.0 and 2.2 mK, respectively, in a velocity bin of 0.59 km s^-1. The continuum level is 3.5+/-0.2 mK in B68 and 11.4+/-0.4 mK in L1544. No significant feature is detected in B68 and the 3 sigma upper limit is consistent with a column density of o-H2O N(o-H2O) < 2.5x10^13 cm^-2, or a fractional abundance x(o-H2O) < 1.3x10^-9, more than an order of magnitude lower than the SWAS upper limit on this source. The L1544 spectrum shows an absorption feature at a 5 sigma level from which we obtain the first value of the o-H2O column density ever measured in dark clouds: N(o-H2O) = (8+/-4)x10^12 cm^-2. The corresponding fractional abundance is x(o-H2O) ~ 5x10^-9 at radii > 7000 AU and ~2x10^-10 toward the center. The radiative transfer analysis shows that this is consistent with a x(o-H2O) profile peaking at ~10^-8, 0.1 pc away from the core center, where both freeze-out and photodissociation are negligible. Herschel has provided the first measurement of water vapor in dark regions. Prestellar cores such as L1544 (with their high central densities, strong continuum, and large envelopes) are very promising tools to finally shed light on the solid/vapor balance of water in molecular clouds., Accepted for publication in Astronomy and Astrophysics (HIFI first results issue)
Published: 2010

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