The Herschel Dwarf Galaxy Survey
In: Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, 2019, 626, pp.A23. ⟨10.1051/0004-6361/201834457⟩ Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 626, pp.A23. ⟨10.1051/0004-6361/201834457⟩ ASTRONOMY & ASTROPHYSICS; (2019-04-20)
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Zugriff:
The sensitive infrared telescopes, Spitzer and Herschel, have been used to target low-metallicity star-forming galaxies, allowing us to investigate the properties of their interstellar medium (ISM) in unprecedented detail. Interpretation of the observations in physical terms relies on careful modeling of those properties. We have employed a multiphase approach to model the ISM phases (HII region and photodissociation region) with the spectral synthesis code Cloudy. Our goal is to characterize the physical conditions (gas densities, radiation fields, etc.) in the ISM of the galaxies from the Herschel Dwarf Galaxy Survey. We are particularly interested in correlations between those physical conditions and metallicity or star-formation rate. Other key issues we have addressed are the contribution of different ISM phases to the total line emission, especially of the [CII]157um line, and the characterization of the porosity of the ISM. We find that the lower-metallicity galaxies of our sample tend to have higher ionization parameters and galaxies with higher specific star-formation rates have higher gas densities. The [CII] emission arises mainly from PDRs and the contribution from the ionized gas phases is small, typically less than 30% of the observed emission. We also find correlation - though with scatter - between metallicity and both the PDR covering factor and the fraction of [CII] from the ionized gas. Overall, the low metal abundances appear to be driving most of the changes in the ISM structure and conditions of these galaxies, and not the high specific star-formation rates. These results demonstrate in a quantitative way the increase of ISM porosity at low metallicity. Such porosity may be typical of galaxies in the young Universe.
Accepted in A&A. 20 pages, 12 figures, 5 tables plus appendices
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The Herschel Dwarf Galaxy Survey
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| Autor/in / Beteiligte Person: | Polles, F. L. ; I. De Looze ; Cormier, Diane ; Hony, Sacha ; Lambert-Huyghe, A. ; Abel, N. P. ; Galliano, Frédéric ; Madden, S. C. ; Lebouteiller, Vianney ; Galametz, Maud ; Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay ; Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)) ; Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7) ; Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA) ; Observatorium, Sterrenkundig ; Gent, Universiteit ; University of Cambridge [UK] (CAM) ; Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) ; University of Cincinnati (UC) ; Zentrum für Astronomie der Universität Heidelberg (ZAH) ; Universität Heidelberg [Heidelberg] = Heidelberg University ; Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)) ; 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 de Cergy Pontoise (UCP) ; Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) ; Universiteit Gent = Ghent University (UGENT) ; University College of London [London] (UCL) ; Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES.NASA and SOFIA through grant program SOF 05-0084.DFG program HO 5475/2-1.Research Foundation – Flanders(FWO). DAAD/PROCOPE projects 57210883/35265PE. ; European Project: 702622,H2020,H2020-MSCA-IF-2015,eGALISM(2017) ; Universität Heidelberg [Heidelberg] ; Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP) ; Université Paris-Seine-Université Paris-Seine-Observatoire de Paris ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL) ; PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP) |
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| Quelle: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, 2019, 626, pp.A23. ⟨10.1051/0004-6361/201834457⟩ Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 626, pp.A23. ⟨10.1051/0004-6361/201834457⟩ ASTRONOMY & ASTROPHYSICS; (2019-04-20) |
| Veröffentlichung: | HAL CCSD, 2019 |
| Medientyp: | unknown |
| ISSN: | 0004-6361 (print) ; 1432-0746 (print) |
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