Sign on

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:1302.5430)
· On-line Data
· References in the article
· Citations to the Article (3) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (13)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
A multiwavelength study of the Magellanic-type galaxy NGC 4449 - I. Modelling the spectral energy distribution, the ionization structure and the star formation history
Authors:
Karczewski, O. L.; Barlow, M. J.; Page, M. J.; Kuin, N. P. M.; Ferreras, I.; Baes, M.; Bendo, G. J.; Boselli, A.; Cooray, A.; Cormier, D.; De Looze, I.; Galametz, M.; Galliano, F.; Lebouteiller, V.; Madden, S. C.; Pohlen, M.; Rémy-Ruyer, A.; Smith, M. W. L.; Spinoglio, L.
Affiliation:
AA(Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK; ), AB(Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK), AC(Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking RH5 6NT, UK), AD(Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking RH5 6NT, UK), AE(Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking RH5 6NT, UK), AF(Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281-S9, 9000 Gent, Belgium), AG(UK ALMA Regional Centre Node, Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL, UK), AH(LAM, Université d'Aix-Marseille & CNRS, UMR7326, 38 rue F. Joliot-Curie, 13388 Marseille, France), AI(Department of Physics & Astronomy, University of California, Irvine, CA 92697, USA), AJ(Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France), AK(Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281-S9, 9000 Gent, Belgium), AL(Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK), AM(Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France), AN(Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France), AO(Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France), AP(School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK), AQ(Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France), AR(School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK), AS(Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma, Italy)
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 431, Issue 3, p.2493-2512 (MNRAS Homepage)
Publication Date:
05/2013
Origin:
OUP
Astronomy Keywords:
methods: numerical, dust, extinction, galaxies: dwarf, galaxies: individual: NGC 4449, galaxies: ISM, galaxies: stellar content
Abstract Copyright:
2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
DOI:
10.1093/mnras/stt345
Bibliographic Code:
2013MNRAS.431.2493K

Abstract

We present an integrated photometric spectral energy distribution (SED) of the Magellanic-type galaxy NGC 4449 from the far-ultraviolet (UV) to the submillimetre, including new observations acquired by the Herschel Space Observatory. We include integrated UV photometry from the Swift Ultraviolet and Optical Telescope using a measurement technique which is appropriate for extended sources with coincidence loss. In this paper, we examine the available multiwavelength data to infer a range of ages, metallicities and star formation rates for the underlying stellar populations, as well as the composition and the total mass of dust in NGC 4449. Our analysis of the global optical spectrum of NGC 4449 fitted using the spectral fitting code STARLIGHT suggests that the majority of stellar mass resides in old (≳1 Gyr old) and metal-poor (Z/Z&sun; ˜ 0.2) populations, with the first onset of star formation activity deduced to have taken place at an early epoch, approximately 12 Gyr ago. A simple chemical evolution model, suitable for a galaxy continuously forming stars, suggests a ratio of carbon to silicate dust mass comparable to that of the Large Magellanic Cloud over the inferred time-scales. We present an iterative scheme, which allows us to build an in-depth and multicomponent representation of NGC 4449 `bottom-up', taking advantage of the broad capabilities of the photoionization and radiative transfer code MOCASSIN (MOnte CArlo SimulationS of Ionized Nebulae). We fit the observed SED, the global ionization structure and the emission line intensities, and infer a recent star formation rate of 0.4 M&sun; yr- 1 and a total stellar mass of ≈ 1 × 109 M&sun; emitting with a bolometric luminosity of 5.7 × 109 L&sun;. Our fits yield a total dust mass of 2.9 ± 0.5 × 106 M&sun; including 2 per cent attributed to polycyclic aromatic hydrocarbons. We deduce a dust to gas mass ratio of 1/190 within the modelled region. While we do not consider possible additional contributions from even colder dust, we note that including the extended H I envelope and the molecular gas is likely to bring the ratio down to as low as ˜1/800.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

  New!

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints