Disentangling the metallicity and star formation history of HII galaxies through tailor-made models

Details Disentangling the metallicity and star formation history of HII galaxies through tailor-made models Disentangling the metallicity and star formation history of HII galaxies through tailor-made models

2010-01-27

arxiv.org/abs/1001.4828v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

20 pages, 12 figures, MNRAS (in press)

Scientific paper

We present a self-consistent study of the stellar populations and the ionized gas in a sample of 10 HII galaxies with, at least, four measured electron temperatures and a precise determination of ionic abundances following the "direct method". We fitted the spectral energy distribution of the galaxies using the program STARLIGHT in order to quantify the contribution of the underlying stellar population to EW(Hbeta), which amounts to about 10% for most of the objects. We then studied the Wolf-Rayet stellar populations detected in seven of the galaxies. The presence of these populations and the corrected EW(Hbeta) values indicate that the ionizing stellar populations were created following a continuous star formation episode of 10 Myr duration, hence WR stars may be present in all of objects even if they are not detected in some of them. The derived stellar features, the number of ionizing photons and the relative intensities of the strongest emission lines were used as input parameters to compute tailored models with the photoionization code CLOUDY. Our models are able to y reproduce their thermal and ionization structure as deduced from their collisionally excited emission lines and, hence, no abundance discrepancy factors are implied for this kind of objects. Only the electron temperature of S+ is overestimated by the models, pointing to the possible presence of outer shells of diffuse gas in these objects. This kind of geometrical effects can affect the determination of the equivalent effective temperature of the ionizing cluster using calibrators which depend on low-excitation emission lines.

Affiliated with

Also associated with

No associations

Rating

Disentangling the metallicity and star formation history of HII galaxies through tailor-made models does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Disentangling the metallicity and star formation history of HII galaxies through tailor-made models, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disentangling the metallicity and star formation history of HII galaxies through tailor-made models will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-238331