The nature of the Wolf-Rayet galaxy Mrk 209 from photoionization models
arXiv:astro-ph/0703319 · doi:10.1111/j.1365-2966.2007.11670.x
Abstract
We present a detailed photoionisation model of the brightest knot of star format ion in the blue compact dwarf galaxy Mrk 209. The model reproduces the intensiti es of main lines emitted by the ionised gas, resulting in a very good agreement between observed and predicted line temperatures and chemical abundances of the observed ionic species. The model has been calculated using the spectral energy distribution of a massive cluster of recent formation as the ionising source. The features of Wolf-Rayet stars observed in the spectrum of the object, along with its ionising properties, lead to different solutions for the ages and characteristics of the ionising stellar populations.The found solutions are compatible with either a composite population of two ionising clusters or a continuous star formation. In the first case, a young cluster, with an age less than 3 Myr, would be responsible for most of the ionisation properties while an older cluster, with either 3.2 or 4.2 Myr, would be responsible for the emission of the observed WR features in the spectrum of the knot. In the second case, the duration of the star formation episode is found to be 3.6 Myr. The addition of a certain amout of dust was required in order to reproduce correctly the measured electron temperatures. This dust implies a gas/dust ratio identical to that in the Milky Way, and a fraction of absorbed photons of f = 0.58. The taking into account the dust grain physics combined with a thick-shell geometry solves the problem of the heating in this object and allows the fitting of the auroral lines, the line temperatures and the ionisation structure of the nebula with a negligible presence of temperature fluctuations, in agreement with the most recent results found for this type of objects from the measurement of the Balmer jump temperature.
arXiv comment13 pages, 14 figures, in press in MNRAS, LaTeX: typos added, references removed
References in corpus (22)
- Starburst99: Synthesis Models for Galaxies with Active Star Formation
- Realistic Ionizing Fluxes for Young Stellar Populations from 0.05 to twice solar metallicity
- Palomar/Las Campanas Imaging Atlas of Blue Compact Dwarf galaxies: I. Images and integrated photometry
- Mid Infrared Properties of Low Metallicity Blue Compact Dwarf Galaxies From Spitzer/IRS
- A Spectroscopic Study of a Large Sample of Wolf-Rayet Galaxies
- Line temperatures and elemental abundances in HII galaxies
- ISO spectroscopy of compact HII regions in the Galaxy. II Ionization and elemental abundances
- Confidence levels of evolutionary synthesis models III: On sampling and Poissonian fluctuations
- Grain size distributions and photo-electric heating in ionized media
- The temperature and ionization structure of the emitting gas in HII galaxies: Implications for the accuracy of abundance determinations
- Modeling the emission line sequence of H II galaxies
- The massive stellar content in NGC604 and its evolutionary state
- A Reexamination of Electron Density Diagnostics for Ionized Gaseous Nebulae
- A Near-Infrared Stellar Census of Blue Compact Dwarf Galaxies: The Wolf-Rayet Galaxy I Zw 36
- Balmer and Paschen jump temperature determinations in low-metallicity emission-line galaxies
- Abundance patterns in the low-metallicity emission-line galaxies from the Early Data Release of the Sloan Digital Sky Survey
- Baade's red sheet resolved into stars with HST in the Blue Compact Dwarf Galaxy VII Zw 403
- How old are the HII Galaxies?
- Population synthesis of HII galaxies
- An empirical calibration of sulphur abundance in ionised gaseous nebulae
- New insights to the photometric structure of Blue Compact Dwarf Galaxies from deep Near-Infrared studies: II. The sample of northern BCDs
- ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations
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