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A multiwavelength study of the Magellanic-type galaxy NGC 4449-I. Modelling the spectral energy distribution, the ionization structure and the star formation history
- Source :
- Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2013, 431 (3), pp.2493--2512. ⟨10.1093/mnras/stt345⟩, Monthly Notices of the Royal Astronomical Society, 2013, 431 (3), pp.2493--2512. ⟨10.1093/mnras/stt345⟩, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
- Publication Year :
- 2013
- Publisher :
- HAL CCSD, 2013.
-
Abstract
- [Abridged] 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. 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 SFR of 0.4 Msolar/yr and a total stellar mass of approximately 1e9 Msolar emitting with a bolometric luminosity of 5.7e9 Lsolar. Our fits yield a total dust mass of 2.9e6 Msolar 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 HI envelope and the molecular gas is likely to bring the ratio down to as low as ~ 1/800.<br />22 pages, 11 figures, 8 tables, published in MNRAS, 431, 2493 (2013)
- Subjects :
- Cosmology and Nongalactic Astrophysics (astro-ph.CO)
DWARF GALAXIES
Stellar mass
dwarf [galaxies]
Astrophysics::High Energy Astrophysical Phenomena
INFRARED-EMISSION
Extinction (astronomy)
FOS: Physical sciences
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
Luminosity
POLYCYCLIC AROMATIC-HYDROCARBONS
IRREGULAR GALAXIES
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Large Magellanic Cloud
010303 astronomy & astrophysics
Instrumentation and Methods for Astrophysics (astro-ph.IM)
Astrophysics::Galaxy Astrophysics
QB
Physics
ISM [galaxies]
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
010308 nuclear & particles physics
Star formation
individual: NGC 4449 [galaxies]
extinction
Astronomy
Astronomy and Astrophysics
numerical [methods]
stellar content [galaxies]
ON-ORBIT PERFORMANCE
HERSCHEL PHOTOMETRIC-OBSERVATIONS
DIFFUSE INTERSTELLAR-MEDIUM
Galaxy
Physics and Astronomy
13. Climate action
Space and Planetary Science
Spectral energy distribution
DIGITAL SKY SURVEY
dust
Astrophysics::Earth and Planetary Astrophysics
SWIFT ULTRAVIOLET/OPTICAL TELESCOPE
Irregular galaxy
Astrophysics - Instrumentation and Methods for Astrophysics
STELLAR POPULATION-MODELS
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00358711 and 13652966
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2013, 431 (3), pp.2493--2512. ⟨10.1093/mnras/stt345⟩, Monthly Notices of the Royal Astronomical Society, 2013, 431 (3), pp.2493--2512. ⟨10.1093/mnras/stt345⟩, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
- Accession number :
- edsair.doi.dedup.....b807374e707fc6c89db7545b76734da8