15 results on '"Olmi, L."'
Search Results
2. The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71⋅º 0 < ℓ < 67⋅º 0)
- Author
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Elia, D, Molinari, S, Schisano, E, Pestalozzi, M, Pezzuto, S, Merello, M, Noriega-Crespo, A, Moore, TJT, Russeil, D, Mottram, JC, Paladini, R, Strafella, F, Benedettini, M, Bernard, JP, Di Giorgio, A, Eden, DJ, Fukui, Y, Plume, R, Bally, J, Martin, PG, Ragan, SE, Jaffa, SE, Motte, F, Olmi, L, Schneider, N, Testi, L, Wyrowski, F, Zavagno, A, Calzoletti, L, Faustini, F, Natoli, P, Palmeirim, P, Piacentini, F, Piazzo, L, Pilbratt, GL, Polychroni, D, Baldeschi, A, Beltrán, MT, Billot, N, Cambrésy, L, Cesaroni, R, García-Lario, P, Hoare, MG, Huang, M, Joncas, G, Liu, SJ, Maiolo, BMT, Marsh, KA, Maruccia, Y, Mège, P, Peretto, N, Rygl, KLJ, Schilke, P, Thompson, MA, Traficante, A, Umana, G, Veneziani, M, Ward-Thompson, D, Whitworth, AP, Arab, H, Bandieramonte, M, Becciani, U, Brescia, M, Buemi, C, Bufano, F, Butora, R, Cavuoti, S, Costa, A, Fiorellino, E, Hajnal, A, Hayakawa, T, Kacsuk, P, Leto, P, Li Causi, G, Marchili, N, Martinavarro-Armengol, S, Mercurio, A, Molinaro, M, Riccio, G, Sano, H, Sciacca, E, Tachihara, K, Torii, K, Trigilio, C, Vitello, F, and Yamamoto, H
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Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 μm. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane −71⋅º0 < ℓ < 67⋅º0. The band-merged catalogue contains 100 922 sources with a regular SED, 24 584 of which show a 70-μm counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between ‘on-arm’ and ‘interarm’ positions.
- Published
- 2017
3. The Hi-GAL compact source catalogue.\ud I. The physical properties of the clumps in the inner\ud Galaxy (−71.0 ◦ < ' < 67.0◦)
- Author
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Elia, D., Molinari, S., Schisano, E., Pestalozzi, M., Pezzuto, S., Merello, M., Noriega-Crespo, A., Moore, T. J. T., Russeil, D., Mottram, J. C., Paladini, R., Strafella, F., Benedettini, M., Bernard, J. P., Di Giorgio, A., Eden, D. J., Fukui, Y., Plume, R., Bally, J., Martin, P. G., Ragan, Sarah, Jaffa, Sarah, Motte, F., Olmi, L., Schneider, N., Testi, L., Wyrowski, F., Zavagno, A., Calzoletti, L., Faustini, F., Natoli, P., Palmerim, P., Piacentini, F., Piazzo, L., Pilbratt, G. L., Polychroni, D., Baldeschi, A., Beltran, M. T., Billot, N., Cambresy, L., Cesaroni, R., Garcia-Lario, P., Hoare, M. G., Huang, M., Joncas, G., Liu, S. J., Maiolo, B. M. T., Marsh, K. A., Maruccia, Y., Mege, P., Peretto, Nicolas, Rygl, K. L. J., Schilke, P., Thompson, M. A., Traficante, A., Umana, G., Veneziani, M., Ward-Thompson, D., and Whitworth, Anthony Peter
- Subjects
Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics ,QB - Abstract
Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 μm. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane −71∘.0 < ℓ < 67∘.0. The band-merged catalogue contains 100 922 sources with a regular SED, 24 584 of which show a 70-μm counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between ‘on-arm’ and ‘interarm’ positions.
- Published
- 2017
4. Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ}< \ell < 67.0^{\circ}$)
- Author
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Elia, D., Molinari, S., Schisano, E., Pestalozzi, M., Pezzuto, S., Merello, M., Noriega-Crespo, A., Moore, T. J. T., Russeil, D., Mottram, J. C., Paladini, R., Strafella, F., Benedettini, M., Bernard, J. P., Di Giorgio, A., Eden, D. J., Fukui, Y., Plume, R., Bally, J., Martin, P. G., Ragan, S. E., Jaffa, S. E., Motte, F., Olmi, L., Schneider, N., Testi, L., Wyrowski, F., Zavagno, A., Calzoletti, L., Faustini, F., Natoli, P., Palmerim, P., Piacentini, F., Piazzo, L., Pilbratt, G. L., Polychroni, D., Baldeschi, A., Beltrán, M. T., Billot, N., Cambrésy, L., Cesaroni, R., García-Lario, P., Hoare, M. G., Huang, M., Joncas, G., Liu, S. J., Maiolo, B. M. T., Marsh, K. A., Maruccia, Y., Mège, P., Peretto, N., Rygl, K. L. J., Schilke, P., Thompson, M. A., Traficante, A., Umana, G., Veneziani, M., Ward-Thompson, D., Whitworth, A. P., Arab, H., Bandieramonte, M., Becciani, U., Brescia, M., Buemi, C., Bufano, F., Butora, R., Cavuoti, S., Costa, A., Fiorellino, E., Hajnal, A., Hayakawa, T., Kacsuk, P., Leto, P., Causi, G. Li, Marchili, N., Martinavarro-Armengol, S., Mercurio, A., Molinaro, M., Riccio, G., Sano, H., Sciacca, E., Tachihara, K., Torii, K., Trigilio, C., Vitello, F., and Yamamoto, H.
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Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics::Galaxy Astrophysics - Abstract
Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 $\mu$m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogs presented in Molinari et al. (2016a), covering the portion of Galactic plane $-71.0^{\circ}< \ell < 67.0^{\circ}$. The band-merged catalogue contains 100922 sources with a regular SED, 24584 of which show a 70 $\mu$m counterpart and are thus considered proto-stellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterise different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in proto-stellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to proto-stellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between "on-arm" and "inter-arm" positions., Comment: Accepted by MNRAS
- Published
- 2017
5. Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ}< \ell < 67.0^{\circ}$)
- Author
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Elia, D., Molinari, S., Schisano, E., Pestalozzi, M., Pezzuto, S., Merello, M., Noriega-Crespo, A., Moore, T. J. T., Russeil, D., Mottram, J. C., Paladini, R., Strafella, F., Benedettini, M., Bernard, J. P., Di Giorgio, A., Eden, D. J., Fukui, Y., Plume, R., Bally, J., Martin, P. G., Ragan, S. E., Jaffa, S. E., Motte, F., Olmi, L., Schneider, N., Testi, L., Wyrowski, F., Zavagno, A., Calzoletti, L., Faustini, F., Natoli, P., Palmerim, P., Piacentini, F., Piazzo, L., Pilbratt, G. L., Polychroni, D., Baldeschi, A., Beltr��n, M. T., Billot, N., Cambr��sy, L., Cesaroni, R., Garc��a-Lario, P., Hoare, M. G., Huang, M., Joncas, G., Liu, S. J., Maiolo, B. M. T., Marsh, K. A., Maruccia, Y., M��ge, P., Peretto, N., Rygl, K. L. J., Schilke, P., Thompson, M. A., Traficante, A., Umana, G., Veneziani, M., Ward-Thompson, D., Whitworth, A. P., Arab, H., Bandieramonte, M., Becciani, U., Brescia, M., Buemi, C., Bufano, F., Butora, R., Cavuoti, S., Costa, A., Fiorellino, E., Hajnal, A., Hayakawa, T., Kacsuk, P., Leto, P., Causi, G. Li, Marchili, N., Martinavarro-Armengol, S., Mercurio, A., Molinaro, M., Riccio, G., Sano, H., Sciacca, E., Tachihara, K., Torii, K., Trigilio, C., Vitello, F., and Yamamoto, H.
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Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 $��$m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogs presented in Molinari et al. (2016a), covering the portion of Galactic plane $-71.0^{\circ}< \ell < 67.0^{\circ}$. The band-merged catalogue contains 100922 sources with a regular SED, 24584 of which show a 70 $��$m counterpart and are thus considered proto-stellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterise different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in proto-stellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to proto-stellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between "on-arm" and "inter-arm" positions., Accepted by MNRAS
- Published
- 2017
- Full Text
- View/download PDF
6. The YSO Population in the Vela-D Molecular Cloud
- Author
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Strafella, F., Lorenzetti, D., Giannini, T., Elia, D., Maruccia, Y., Maiolo, B., Massi, F., Olmi, L., Molinari, S., and Pezzuto, S.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
We investigate the young stellar population in the Vela Molecular Ridge, Cloud-D (VMR-D), a star forming (SF) region observed by both Spitzer/NASA and Herschel/ESA space telescope. The point source, band-merged, Spitzer-IRAC catalog complemented with MIPS photometry previously obtained is used to search for candidate young stellar objects (YSO), also including sources detected in less than four IRAC bands. Bona fide YSO are selected by using appropriate color-color and color-magnitude criteria aimed to exclude both Galatic and extragalactic contaminants. The derived star formation rate and efficiency are compared with the same quantities characterizing other SF clouds. Additional photometric data, spanning from the near-IR to the submillimeter, are used to evaluate both bolometric luminosity and temperature for 33 YSOs located in a region of the cloud observed by both Spitzer and Herschel. The luminosity-temperature diagram suggests that some of these sources are representative of Class 0 objects with bolometric temperatures below 70 K and luminosities of the order of the solar luminosity. Far IR observations from the Herschel/Hi-GAL key project for a survey of the Galactic plane are also used to obtain a band-merged photometric catalog of Herschel sources aimed to independently search for protostars. We find 122 Herschel cores located on the molecular cloud, 30 of which are protostellar and 92 starless. The global protostellar luminosity function is obtained by merging the Spitzer and Herschel protostars. Considering that 10 protostars are found in both Spitzer and Herschel list it follows that in the investigated region we find 53 protostars and that the Spitzer selected protostars account for approximately two-thirds of the total., Comment: 40 pages, 12 figures, accepted for publication in ApJ
- Published
- 2014
- Full Text
- View/download PDF
7. The first hi-gal observations of the outer galaxy: A look at star formation in the third galactic quadrant in the longitude range 216.°5 ≲ ℓ ≲ 225.°5
- Author
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Elia, D. Molinari, S. Fukui, Y. Schisano, E. Olmi, L. Veneziani, M. Hayakawa, T. Pestalozzi, M. Schneider, N. Benedettini, M. Di Giorgio, A.M. Ikhenaode, D. Mizuno, A. Onishi, T. Pezzuto, S. Piazzo, L. Polychroni, D. Rygl, K.L.J. Yamamoto, H. Maruccia, Y.
- Subjects
Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present the first Herschel PACS and SPIRE photometric observations in a portion of the outer Galaxy (216.°5 ≲ ℓ ≲ 225.°5 and -2° ≲ b ≲ 0°) as a part of the Hi-GAL survey. The maps between 70 and 500 μm, the derived column density and temperature maps, and the compact source catalog are presented. NANTEN CO(1-0) line observations are used to derive cloud kinematics and distances so that we can estimate distance-dependent physical parameters of the compact sources (cores and clumps) having a reliable spectral energy distribution that we separate into 255 proto-stellar and 688 starless sources. Both typologies are found in association with all the distance components observed in the field, up to 5.8 kpc, testifying to the presence of star formation beyond the Perseus arm at these longitudes. Selecting the starless gravitationally bound sources, we identify 590 pre-stellar candidates. Several sources of both proto- and pre-stellar nature are found to exceed the minimum requirement for being compatible with massive star formation based on the mass-radius relation. For the pre-stellar sources belonging to the Local arm (d ≲ 1.5 kpc) we study the mass function whose high-mass end shows a power law N(log M)M -1.0 ± 0.2. Finally, we use a luminosity versus mass diagram to infer the evolutionary status of the sources, finding that most of the proto-stellar sources are in the early accretion phase (with some cases compatible with a Class I stage), while for pre-stellar sources, in general, accretion has not yet started. © 2013. The American Astronomical Society. All rights reserved.
- Published
- 2013
8. The first Hi-GAL observations of the outer Galaxy: a look to star formation in the third Galactic quadrant in the longitude range 216.5 < l < 225.5
- Author
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Elia, D., Molinari, S., Fukui, Y., Schisano, E., Olmi, L., Veneziani, M., Hayakawa, T., Pestalozzi, M., Schneider, N., Benedettini, M., Di Giorgio, A. M., Ikhenaode, D., Mizuno, A., Onishi, T., Pezzuto, S., Piazzo, L., Polychroni, D., Rygl, K. L. J., Yamamoto, H., and Maruccia, Y.
- Subjects
Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present the first Herschel PACS and SPIRE photometric observations in a portion of the outer Galaxy ($216.5^{\circ} \lesssim \ell \lesssim 225.5^{\circ}$ and $-2^{\circ} \lesssim b \lesssim 0^{\circ}$) as a part of the Hi-GAL survey. The maps between 70 and 500 $��$m, the derived column density and temperature maps, and the compact source catalog are presented. NANTEN CO(1-0) line observations are used to derive cloud kinematics and distances, so that we can estimate distance-dependent physical parameters of the compact sources (cores and clumps) having a reliable spectral energy distribution, that we separate in 255 proto-stellar and 688 starless. Both typologies are found in association with all the distance components observed in the field, up to $\sim 5.8$ kpc, testifying the presence of star formation beyond the Perseus arm at these longitudes. Selecting the starless gravitationally bound sources we identify 590 pre-stellar candidates. Several sources of both proto- and pre-stellar nature are found to exceed the minimum requirement for being compatible with massive star formation, based on the mass-radius relation. For the pre-stellar sources belonging to the Local arm ($d\lesssim1.5$ kpc) we study the mass function, whose high-mass end shows a power-law $N(\log M) \propto M^{-1.0 \pm 0.2}$. Finally, we use a luminosity vs mass diagram to infer the evolutionary status of the sources, finding that most of the proto-stellar are in the early accretion phase (with some cases compatible with a Class I stage), while for pre-stellar sources, in general, accretion has not started yet., Accepted by ApJ
- Published
- 2013
- Full Text
- View/download PDF
9. On the shape of the mass-function of dense clumps in the Hi-GAL fields. I. SED determination and global properties of the mass-functions
- Author
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Olmi, L., Angles-Alcazar, D., Elia, D., Molinari, S., Montier, L., Pestalozzi, M., Pezzuto, S., Polychroni, D., Ristorcelli, I., Rodon, J., Schisano, E., Smith, M. D., Testi, L., and Thompson, M.
- Subjects
Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics::Galaxy Astrophysics - Abstract
Stars form in dense, dusty clumps of molecular clouds, but little is known about their origin and evolution. In particular, the relationship between the mass distribution of these clumps (also known as the "clump mass function", or CMF) and the stellar initial mass function (IMF), is still poorly understood. In order to discern the "true" shape of the CMF and to better understand how the CMF may evolve toward the IMF, large samples of bona-fide pre- and proto-stellar clumps are required. The sensitive observations of the Herschel Space Observatory (HSO) are now allowing us to look at large clump populations in various clouds with different physical conditions. We analyse two fields in the Galactic plane mapped by HSO during its science demonstration phase, as part of the more complete and unbiased Herschel infrared GALactic Plane Survey (Hi-GAL). These fields undergo a source-extraction and flux-estimation pipeline, which allows us to obtain a sample with thousands of clumps. Starless and proto-stellar clumps are separated using both color and positional criteria to find those coincident with MIPS 24 micron sources. We describe the probability density functions of the power-law and lognormal models that are used to fit the CMFs, and we then find their best-fit parameters. For the lognormal model we apply several statistical techniques to the data and compare their results. The CMFs of the two SDP fields show very similar shapes, but very different mass scales. This similarity is confirmed by the values of the best-fit parameters of either the power-law or lognormal model. The power-law model leads to almost identical CMF slopes, whereas the lognormal model shows that the CMFs have similar widths. The similar CMF shape but different mass scale represents an evidence that the overall process of star formation in the two regions is very different., Comment: This article is composed of 14 pages, 5 figures and is based on Hi-GAL data. Submitted for publication to Astronomy & Astrophysics on 19 sept. 2012
- Published
- 2012
- Full Text
- View/download PDF
10. The BLAST 250 \u03bcm-selected galaxy population in GOODS-South
- Author
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Dunlop, J. S., Ade, P. A. R., Bock, J. J., Chapin, E. L., Cirasuolo, M., Coppin, K. E. K., Devlin, M. J., Griffin, M., Greve, T. R., Gundersen, J. O., Halpern, M., Hargrave, P. C., Hughes, D. H., Ivison, R. J., Klein, J., Kovacs, A., Marsden, G., Mauskopf, P., Netterfield, C. B., Olmi, L., Pascale, E., Patanchon, G., Rex, M., Scott, D., Semisch, C., Smail, I., Targett, T. A., Thomas, N., Truch, M. D. P., Tucker, C., Tucker, G. S., Viero, M. P., Walter, F., Wardlow, J. L., Weiss, A., and Wiebe, D. V.
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Galaxies: fundamental parameters ,Space and Planetary Science ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxies: active ,Galaxies: photometry ,Infrared: galaxies ,Galaxies: starburst ,Astrophysics::Galaxy Astrophysics - Abstract
We identify and investigate the nature of the 20 brightest 250μm sources detected by the Balloon-borne Large Aperture Submillimetre Telescope (BLAST) within the central 150arcmin2 of the Great Observatories Origins Deep Survey (GOODS)-South field. Aided by the available deep VLA 1.4GHz radio imaging, reaching S1.4 ~= 40μJy (4σ), we have identified radio counterparts for 17/20 of the 250μm sources. The resulting enhanced positional accuracy of ~=1arcsec has then allowed us to exploit the deep optical (Hubble Space Telescope), near-infrared (VLT) and mid-infrared (Spitzer) imaging of GOODS-South to establish secure galaxy counterparts for the 17 radio-identified sources, and plausible galaxy candidates for the three radio-unidentified sources. Confusion is a serious issue for this deep BLAST 250μm survey, due to the large size of the beam. Nevertheless, we argue that our chosen counterparts are significant, and often dominant contributors to the measured BLAST flux densities. For all of these 20 galaxies we have been able to determine spectroscopic (eight) or photometric (12) redshifts. The result is the first near-complete redshift distribution for a deep 250μm-selected galaxy sample. This reveals that 250μm surveys reaching detection limits of ~=40mJy have a median redshift z ~= 1, and contain not only low-redshift spirals/LIRGs, but also the extreme z ~= 2 dust-enshrouded starburst galaxies previously discovered at sub-millimetre wavelengths. Inspection of the LABOCA 870μm imaging of GOODS-South yields detections of ~=1/3 of the proposed BLAST sources (all at z > 1.5), and reveals 250/870μm flux-density ratios consistent with a standard 40K modified blackbody fit with a dust emissivity index β = 1.5. Based on their Infrared Array Camera (IRAC) colours, we find that virtually all of the BLAST galaxy identifications appear better described as analogues of the M82 starburst galaxy, or Sc star-forming discs rather than highly obscured ULIRGs. This is perhaps as expected at low redshift, where the 250μm BLAST selection function is biased towards spectral energy distributions which peak longward of λrest = 100μm. However, it also appears largely true at z ~= 2.
- Published
- 2010
11. The Hi-GAL catalogue of dusty filamentary structures in the Galactic Plane
- Author
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Stefano Pezzuto, Alberto Noriega-Crespo, Manuel Merello, David Eden, Giuseppe Riccio, Luca Olmi, Fabio Vitello, Nicolas Peretto, Sergio Molinari, Eva Sciacca, Eugenio Schisano, G. Li Causi, P. Palmeirim, Annie Zavagno, M. T. Beltrán, A. M. di Giorgio, M. Benedettini, Anthony Peter Whitworth, Toby J. T. Moore, Massimo Brescia, Davide Elia, Marco Molinaro, Leonardo Testi, Ugo Becciani, L. Cambresy, G. Umana, A. Baldeschi, S. J. Liu, Alessio Traficante, Stefano Cavuoti, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Capodimonte (OAC), University of Naples Federico II, Liverpool John Moores University (LJMU), Space Telescope Science Institute (STSci), INAF - Osservatorio Astrofisico di Catania (OACT), School of Physics and Astronomy [Cardiff], Cardiff University, Departamento de Astronomia (DAS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Roma (OAR), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica e Ciências do Espaço (IASTRO), European Southern Observatory (ESO), Schisano, E., Molinari, S., Elia, D., Benedettini, M., Olmi, L., Pezzuto, S., Traficante, A., Brescia, M., Cavuoti, S., di Giorgio, A. M., Liu, S. J., Moore, T. J. T., Noriega-Crespo, A., Riccio, G., Baldeschi, A., Becciani, U., Peretto, N., Merello, M., Vitello, F., Zavagno, A., Beltran, M. T., Cambresy, L., Eden, D. J., Li Causi, G., Molinaro, M., Palmeirim, P., Sciacca, E., Testi, L., Umana, G., Whitworth, A. P., and University of Naples Federico II = Università degli studi di Napoli Federico II
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Milky Way ,Stars: formation ,Extinction (astronomy) ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Protein filament ,ISM: cloud ,0103 physical sciences ,Submillimeter: ISM ,010303 astronomy & astrophysics ,Galaxy: structure ,Solar and Stellar Astrophysics (astro-ph.SR) ,ISM ,Astrophysics::Galaxy Astrophysics ,QC ,ISM: general ,QB ,Physics ,Infrared: ISM ,Spiral galaxy ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,010308 nuclear & particles physics ,Star formation ,Molecular cloud ,SM: clouds ,Astronomy and Astrophysics ,Dust ,Extinction ,Galactic plane ,Galaxy: local interstellar matter ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,ISM: dust ,Galaxy:structure ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) - Abstract
The recent data collected by {\it Herschel} have confirmed that interstellar structures with filamentary shape are ubiquitously present in the Milky Way. Filaments are thought to be formed by several physical mechanisms acting from the large Galactic scales down to the sub-pc fractions of molecular clouds, and they might represent a possible link between star formation and the large-scale structure of the Galaxy. In order to study this potential link, a statistically significant sample of filaments spread throughout the Galaxy is required. In this work we present the first catalogue of $32,059$ candidate filaments automatically identified in the Hi-GAL survey of the entire Galactic Plane. For these objects we determined morphological (length, $l^{a}$, and geometrical shape) and physical (average column density, $N_{\rm H_{2}}$, and average temperature, $T$) properties. We identified filaments with a wide range of properties: 2$'$\,$\leq l^{a}\leq$\, 100$'$, $10^{20} \leq N_{\rm H_{2}} \leq 10^{23}$\,cm$^{-2}$ and $10 \leq T\leq$ 35\,K. We discuss their association with the Hi-GAL compact sources, finding that the most tenuous (and stable) structures do not host any major condensation and we also assign a distance to $\sim 18,400$ filaments for which we determine mass, physical size, stability conditions and Galactic distribution. When compared to the spiral arms structure, we find no significant difference between the physical properties of on-arm and inter-arm filaments. We compared our sample with previous studies, finding that our Hi-GAL filament catalogue represents a significant extension in terms of Galactic coverage and sensitivity. This catalogue represents an unique and important tool for future studies devoted to understanding the filament life-cycle., 38 pages, 29 figures, 3 appendices
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- 2020
12. The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71$_.^circ$0 < ℓ < 67$_.^circ$0)
- Author
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Takahiro Hayakawa, David Eden, Melvin Hoare, Francesco Strafella, F. Piacentini, Kenneth A. Marsh, Sergio Molinari, S. E. Jaffa, Pedro García-Lario, Alessio Traficante, Peter Schilke, Kengo Tachihara, G. Joncas, J.-P. Bernard, M. R. Pestalozzi, S. Martinavarro-Armengol, Amata Mercurio, Alessandro Costa, Friedrich Wyrowski, Eva Sciacca, Robert Butora, B. Maiolo, Joseph C. Mottram, Mark Thompson, D. Polychroni, H. Yamamoto, G. Li Causi, P. Palmeirim, M. Benedettini, D. Russeil, Hidetoshi Sano, Kazi L.J. Rygl, Eugenio Schisano, Stefano Cavuoti, Annie Zavagno, Sarah Ragan, John Bally, M. Veneziani, Carla Buemi, A. P. Whitworth, K. Torii, Massimo Brescia, Péter Kacsuk, Davide Elia, Marco Molinaro, Nicola Schneider, Ugo Becciani, Rene Plume, Göran Pilbratt, A. M. di Giorgio, F. Faustini, P. Mège, Luca Calzoletti, Grazia Umana, Stefano Pezzuto, H. Arab, E. Fiorellino, Derek Ward-Thompson, S. J. Liu, Marilena Bandieramonte, M. T. Beltrán, Paolo Leto, Y. Maruccia, Roberta Paladini, Toby J. T. Moore, Giuseppe Riccio, Fabio Vitello, Luca Olmi, N. Marchili, Frédérique Motte, Corrado Trigilio, Ákos Hajnal, Yasuo Fukui, Nicolas Peretto, Alberto Noriega-Crespo, A. Baldeschi, Riccardo Cesaroni, Leonardo Testi, Lorenzo Piazzo, Manuel Merello, L. Cambrésy, Filomena Bufano, Peter G. Martin, Nicolas Billot, Meng-Lin Huang, Paolo Natoli, Elia, D., Molinari, S., Schisano, E., Pestalozzi, M., Pezzuto, Marilena, Merello, M., Noriega-Crespo, A., Moore, T. J. T., Russeil, D., Mottram, J. C., Paladini, R., Strafella, F., Benedettini, M., Bernard, J. P., Di Giorgio, A., Eden, D. J., Fukui, Y., Plume, R., Bally, J., Martin, P. G., Ragan, S. E., Jaffa, S. E., Motte, F., Olmi, L., Schneider, N., Testi, L., Wyrowski, F., Zavagno, A., Calzoletti, L., Faustini, F., Natoli, P., Palmeirim, P., Piacentini, F., Piazzo, L., Pilbratt, G. L., Polychroni, D., Baldeschi, A., Beltrán, M. T., Billot, N., Cambrésy, L., Cesaroni, R., García-Lario, P., Hoare, M. G., Huang, M., Joncas, G., Liu, S. J., Maiolo, B. M. T., Marsh, K. A., Maruccia, Y., Mège, P., Peretto, N., Rygl, K. L. J., Schilke, P., Thompson, M. A., Traficante, A., Umana, G., Veneziani, M., Ward-Thompson, D., Whitworth, A. P., Arab, H., Bandieramonte, M., Becciani, U., Brescia, M., Buemi, C., Bufano, F., Butora, R., Cavuoti, S., Costa, A., Fiorellino, E., Hajnal, A., Hayakawa, T., Kacsuk, P., Leto, P., Li Causi, G., Marchili, N., Martinavarro-Armengol, S., Mercurio, A., Molinaro, M., Riccio, G., Sano, H., Sciacca, E., Tachihara, K., Torii, K., Trigilio, C., Vitello, F., Yamamoto, H., Elia, Davide, Pezzuto, S., Noriega Crespo, A., Strafella, Francesco, García Lario, P., Maiolo, BERLINDA MARIA TERESA, Maruccia, Ylenia, Ward Thompson, D., and Martinavarro Armengol, S.
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Astrophysics and Astronomy ,Infrared ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,cataloghi astronomici, mezzo interstellare, osservazioni infrarosse, osservazioni submillimetriche ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,QC ,QB ,Physics ,Spiral galaxy ,010308 nuclear & particles physics ,Star formation ,Spectral density ,Astronomy ,Astronomy and Astrophysics ,Galactic plane ,Galaxy ,Stars ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,catalogues, ISM clouds, dust, extinction, local interstellar matter, infrared ISM, submillimetre ISM ,Longitude - Abstract
Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 μm. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane −71 ∘. 0 < ℓ < 67 ∘. 0. The band-merged catalogue contains 100 922 sources with a regular SED, 24 584 of which show a 70-μm counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between ‘on-arm’ and ‘interarm’ positions. Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 $\mu$m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogs presented in Molinari et al. (2016a), covering the portion of Galactic plane $-71.0^{\circ}< \ell < 67.0^{\circ}$. The band-merged catalogue contains 100922 sources with a regular SED, 24584 of which show a 70 $\mu$m counterpart and are thus considered proto-stellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterise different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in proto-stellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to proto-stellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between "on-arm" and "inter-arm" positions.
- Published
- 2017
13. The molecular environment of the Galactic star forming region G19.61–0.23
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L. Gregorini, G. Santangelo, Frederic Schuller, Silvia Leurini, Sergio Molinari, Luca Olmi, C. M. Walmsley, Leonardo Bronfman, Alberto Noriega-Crespo, Karl M. Menten, R. Cesaroni, Sean Carey, Leonardo Testi, Santangelo G., Testi L., Leurini S., Walmsley C. M., Cesaroni R., Bronfman L., Carey S., Gregorini L., Menten K. M., Molinari S., and Noriega-Crespo A., Olmi L., Schuller F.
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Physics ,education.field_of_study ,Spiral galaxy ,RADIO CONTINUUM ,Star formation ,Molecular cloud ,ISM: STAR: FORMATION ,Population ,FOS: Physical sciences ,Astronomy and Astrophysics ,ISM:INDIVIDUAL OBJECT:G19.61-0.23 ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galactic plane ,Astrophysics - Astrophysics of Galaxies ,ISM:MOLECULES ,Stars ,Star cluster ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,education ,Astrophysics::Galaxy Astrophysics ,Dwarf galaxy - Abstract
We present single-dish (sub)millimeter observations of gas and dust in the Galactic high-mass star-forming region G19.61-0.23, with the aim of studying the large-scale properties and physical conditions of the molecular gas across the region. The final aim is to compare the large-scale (about 100 pc) properties with the small-scale (about 3 pc) properties and to consider possible implications for extragalactic studies. We have mapped CO isotopologues in the J=1-0 transition using the FCRAO-14m telescope and the J=2-1 transition using the IRAM-30m telescope. We have also used data from the ATLASGAL survey and from the BU-FCRAO Galactic Ring Survey, as well as the Spitzer infrared Galactic plane surveys GLIMPSE and MIPSGAL to characterize the star-formation activity within the molecular clouds. We reveal a population of molecular clumps in the 13CO(1-0) emission. Our analysis of the 13CO suggests that the virial parameter (ratio of kinetic to gravitational energy) varies over an order of magnitude between clumps that are unbound and some that are apparently "unstable". This conclusion is independent of whether they show evidence of ongoing star formation. We find that the majority of ATLASGAL sources have MIPSGAL counterparts with luminosities in the range 10^4 - 5 10^4 Lsun and are presumably forming relatively massive stars. We compare our results with previous extragalactic studies of the nearby spiral galaxies M31 and M33; and the blue compact dwarf galaxy Henize2-10. We find that the main giant molecular cloud surrounding G19.61-0.23 has physical properties typical for Galactic GMCs and which are comparable to the GMCs in M31 and M33. However, the GMC studied here shows smaller surface densities and masses than the clouds identified in Henize2-10 and associated with super star cluster formation., Accepted for publication in Astronomy & Astrophysics
- Published
- 2010
14. The Hi-GAL compact source catalogue – II. The 360° catalogue of clump physical properties
- Author
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Stefano Pezzuto, Sarah Ragan, Kazi L.J. Rygl, Alberto Noriega-Crespo, Lorenzo Piazzo, Luca Olmi, David Eden, Alessio Traficante, Göran Pilbratt, Peter Schilke, Jonathan C. Tan, A. Baldeschi, Rene Plume, P. Palmeirim, Annie Zavagno, Roberta Paladini, M. Benedettini, John Bally, D. Russeil, E. Fiorellino, M. R. Pestalozzi, Peter G. Martin, Davide Elia, Sergio Molinari, D. Polychroni, Manuel Merello, S. J. Liu, A. M. di Giorgio, Toby J. T. Moore, P. Mège, Francesco Strafella, Eugenio Schisano, Elia, D., Merello, M., Molinari, S., Schisano, E., Zavagno, A., Russeil, D., Mege, P., Martin, P. G., Olmi, L., Pestalozzi, M., Plume, R., Ragan, S. E., Benedettini, M., Eden, D. J., Moore, T. J. T., Noriega-Crespo, A., Paladini, R., Palmeirim, P., Pezzuto, S., Pilbratt, G. L., Rygl, K. L. J., Schilke, P., Strafella, F., Tan, J. C., Traficante, A., Baldeschi, A., Bally, J., Giorgio, A. M. D., Fiorellino, E., Liu, S. J., Piazzo, L., Polychroni, D., Department of Physics and Astronomy [Calgary], University of Calgary, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Space Telescope Science Institute (STSci), 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), Universidade do Porto = University of Porto, INAF - Osservatorio Astronomico di Roma (OAR), Universität zu Köln = University of Cologne, European Southern Observatory (ESO), Università degli Studi di Roma Tor Vergata [Roma], Departamento de Astronomia (DAS), Laboratoire d'Astrophysique de Marseille (LAM), and 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)
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Stars: formation ,Extinction (astronomy) ,cloud [ISM] ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,ISM: clouds ,01 natural sciences ,Luminosity ,Photometry (optics) ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,ISM [submillimeter] ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,formation [Stars] ,infrared: ISM ,Physics ,Spiral galaxy ,extinction ,010308 nuclear & particles physics ,Star formation ,local interstellar matter ,ISM [infrared] ,Astronomy and Astrophysics ,Galactic plane ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,[SDU]Sciences of the Universe [physics] ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,submillimeter: ISM ,Spectral energy distribution ,dust ,dust, extinction - Abstract
We present the $360^\circ$ catalogue of physical properties of Hi-GAL compact sources, detected between 70 and 500 $\mu$m. This release not only completes the analogous catalogue previously produced by the Hi-GAL collaboration for $-71^\circ \lesssim \ell \lesssim 67^\circ$, but also meaningfully improves it thanks to a new set of heliocentric distances, 120808 in total. About a third of the 150223 entries are located in the newly added portion of the Galactic plane. A first classification based on detection at 70 $\mu$m as a signature of ongoing star-forming activity distinguishes between protostellar sources (23~per cent of the total) and starless sources, with the latter further classified as gravitationally bound (pre-stellar) or unbound. The integral of the spectral energy distribution, including ancillary photometry from $\lambda=21$ to 1100 $\mu$m, gives the source luminosity and other bolometric quantities, while a modified black body fitted to data for $\lambda \geq 160\, \mu$m yields mass and temperature. All tabulated clump properties are then derived using photometry and heliocentric distance, where possible. Statistics of these quantities are discussed with respect to both source Galactic location and evolutionary stage. No strong differences in the distributions of evolutionary indicators are found between the inner and outer Galaxy. However, masses and densities in the inner Galaxy are on average significantly larger, resulting in a higher number of clumps that are candidates to host massive star formation. Median behaviour of distance-independent parameters tracing source evolutionary status is examined as a function of the Galactocentric radius, showing no clear evidence of correlation with spiral arm positions., Comment: accepted by MNRAS, april 2021
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15. A Herschel study of YSO evolutionary stages and formation timelines in two fields of the Hi-GAL survey
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A. Di Giorgio, Stefano Pezzuto, John Bally, Alessio Traficante, M. R. Pestalozzi, Francesco Strafella, F. Piacentini, Sergio Molinari, L. Calzoletti, Mark Thompson, D. Polychroni, Daniel Anglés-Alcázar, E. Schisano, Thomas P. Robitaille, Davide Elia, Joseph C. Mottram, Milena Benedettini, Roberta Paladini, Guy S. Stringfellow, Paul Martin, Michael D. Smith, Jin-Zeng Li, Leonardo Testi, Luca Olmi, Cara Battersby, M. Veneziani, L. K. Morgan, F. Faustini, Paolo Natoli, Nicolas Billot, Frédérique Motte, Elia, Davide Quintino, Schisano, E., Molinari, S., Robitaille, T., Anglés Alcázar, D., Bally, J., Battersby, C., Benedettini, M., Billot, N., Calzoletti, L., di Giorgio, A. M., Faustini, F., Li, J. Z., Martin, P., Morgan, L., Motte, F., Mottram, J. C., Natoli, P., Olmi, L., Paladini, R., Piacentini, F., Pestalozzi, M., Pezzuto, S., Polychroni, D., Smith, M. D., Strafella, Francesco, Stringfellow, G. S., Testi, L., Thompson, M. A., Traficante, A., and Veneziani, M.
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Physics ,stelle di pre-sequenza principale ,Field (physics) ,Infrared ,Star formation ,FOS: Physical sciences ,Astronomy and Astrophysics ,stars: formation / stars: pre-main sequence ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galactic plane ,Astrophysics - Astrophysics of Galaxies ,formazione stellare ,Luminosity ,Stars ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Spectral energy distribution ,Astrophysics::Solar and Stellar Astrophysics ,Main sequence ,Astrophysics::Galaxy Astrophysics - Abstract
We present a first study of the star-forming compact dust condensations revealed by Herschel in the two 2 \times 2 \degr Galactic Plane fields centered at [l;b] = [30\degr; 0 \degr] and [l;b] = [59\degr; 0 \degr], respectively, and observed during the Science Demonstration Phase for the Herschel infrared Galactic Plane survey (Hi-GAL) Key-Project. Compact source catalogs extracted for the two fields in the five Hi-GAL bands (70, 160, 250, 350 and 500 $\mu$m) were merged based on simple criteria of positional association and spectral energy distribution (SED) consistency into a final catalog which contains only coherent SEDs with counterparts in at least three adjacent Herschel bands. These final source lists contain 528 entries for the l = 30\degr field, and 444 entries for the l = 59\degr field. The SED coverage has been augmented with ancillary data at 24 $\mu$m and 1.1 mm. SED modeling for the subset of 318 and 101 sources (in the two fields, respectively) for which the distance is known was carried out using both a structured star/disk/envelope radiative transfer model and a simple isothermal grey-body. Global parameters like mass, luminosity, temperature and dust properties have been estimated. The Lbol/Menv ratio spans four orders of magnitudes from values compatible with the pre-protostellar phase to embedded massive zero-age main sequence stars. Sources in the l = 59\degr field have on average lower L/M, possibly outlining an overall earlier evolutionary stage with respect to the sources in the l = 30\degr field. Many of these cores are actively forming high-mass stars, although the estimated core surface densities appear to be an order of magnitude below the 1 g cm$^{-2}$ critical threshold for high-mass star formation., Comment: To appear in A&A
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