Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-04-29
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
All these results are included in the paper "Massive Star Formation in Wolf-Rayet galaxies IV. Colours, chemical-composition a
Scientific paper
We have performed a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show a substantial population of very young massive stars, most of them classified as Wolf-Rayet (WR) galaxies. We have analysed optical/NIR colours, physical and chemical properties of the ionized gas, stellar, gas and dust content, star-formation rate and interaction degree (among many other galaxy properties) of our galaxy sample using multi-wavelength data. We compile 41 independent star-forming regions --with oxygen abundances between 12+log(O/H) = 7.58 and 8.75--, of which 31 have a direct estimate of the electron temperature of the ionized gas. This paper, only submitted to astro-ph, compiles the most common empirical calibrations to the oxygen abundance, and presents the comparison between the chemical abundances derived in these galaxies using the direct method with those obtained through empirical calibrations, as it is published in Lopez-Sanchez & Esteban (2010b). We find that (i) the Pilyugin method (Pilyugin 2001a,b; Pilyugin & Thuan 2005) which considers the R23 and the P parameters, is the best suited empirical calibration for these star-forming galaxies, (ii) the relations between the oxygen abundance and the N2 or the O3N2 parameters provided by Pettini & Pagel (2004) give acceptable results for objects with 12+log(O/H)>8.0, and (iii) the results provided by empirical calibrations based on photoionization models (McGaugh, 1991; Kewley & Dopita, 2002; Kobulnicky & Kewley, 2004) are systematically 0.2 -- 0.3 dex higher than the values derived from the direct method. These differences are of the same order that the abundance discrepancy found between recombination and collisionally excited lines. This may suggest the existence of temperature fluctuations in the ionized gas, as exists in Galactic and other extragalactic HII regions.
Esteban Cesar
Lopez-Sanchez Angel R.
No associations
LandOfFree
Massive star formation in Wolf-Rayet galaxies: IV b. Using empirical calibrations to compute the oxygen abundance 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 Massive star formation in Wolf-Rayet galaxies: IV b. Using empirical calibrations to compute the oxygen abundance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Massive star formation in Wolf-Rayet galaxies: IV b. Using empirical calibrations to compute the oxygen abundance will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-284865