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http://hdl.handle.net/20.500.12386/23128
Titolo: | The Herschel Virgo Cluster Survey. XVIII. Star-forming dwarf galaxies in a cluster environment | Autori: | Grossi, M. HUNT, Leslie Kipp Madden, S. C. Hughes, T. M. Auld, R. Baes, M. Bendo, G. J. BIANCHI, SIMONE Bizzocchi, L. Boquien, M. Boselli, A. Clemens, M. CORBELLI, Edvige Cortese, L. Davies, J. De Looze, I. di Serego Alighieri, S. Fritz, J. Pappalardo, C. Pierini, D. Rémy-Ruyer, A. Smith, M. W. L. Verstappen, J. Viaene, S. Vlahakis, C. |
Data pubblicazione: | 2015 | Rivista: | ASTRONOMY & ASTROPHYSICS | Numero: | 574 | Da pagina:: | A126 | Abstract: | To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than m<SUB>B</SUB> = 18 mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by β = 1.5, with a median dust temperature T<SUB>d</SUB> = 22.4 K. Assuming β = 1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500 μm in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of β, while a similarly high fraction (54%) is found if a β-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys,such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and Hi fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 10<SUP>7</SUP> to 10<SUP>11</SUP> M<SUB>☉</SUB>) for both dwarfs and spirals. Highly Hi-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the large dust-to-gas mass ratios observed in these systems, we find that the fraction of dust removed has to be less than that of the Hi component. The cluster environment seems to mostly affect the gas component and star formation activity of the dwarfs. Since the Virgo star-forming dwarfs are likely to be crossing the cluster for the first time, a longer timescale might be necessary to strip the more centrally concentrated dust distribution. <P />Appendices are available in electronic form at <A href="http://www.aanda.org/10.1051/0004-6361/201424866/olm">http://www.aanda.org</A> | Acknowledgments: | M.G. gratefully acknowledges support from the Science and Technology Foundation (FCT, Portugal) through the research grant PTDC/CTE-AST/111140/2009. S.B., E.C., and L.K.H. acknowledge support from PRIN-INAF 2012/2013. SCM and ARR acknowledge support from the Agence Nationale de la Recherche (ANR) through the programme SYMPATICO (Program Blanc Projet ANR-11-BS56-0023). T.M.H. gratefully acknowledges the financial support from the Belgian Science Policy Office (BELSPO) in the frame of the PRODEX project C90370 ( Herschel -PACS Guaranteed Time and Open Time Programs: Science Exploitation). I.D.L. is a postdoctoral researcher of the FWO-Vlaanderen (Belgium). Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/ . SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. We thank the many members of the ALFALFA team who have contributed to the acquisition and processing of the ALFALFA dataset over the last six years. The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968), and in alliance with Ana G. Mandez-Universidad Metropolitana, and the Universities Space Research Association. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. | URI: | http://hdl.handle.net/20.500.12386/23128 | URL: | https://www.aanda.org/articles/aa/abs/2015/02/aa24866-14/aa24866-14.html | ISSN: | 0004-6361 | DOI: | 10.1051/0004-6361/201424866 | Bibcode ADS: | 2015A&A...574A.126G | Fulltext: | open |
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