Spectrophotometric properties of galaxies at intermediate redshifts (z similar to 0.2-1.0) - II. The Luminosity-Metallicity relation

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Lamareille, F (Author) Other; Contini, T (Author) Other; J. Brinchmann (Author) Other; Le Borgne, JF (Author) Other; Charlot, S (Author) Other; Richard, J (Author) Other

Journal

Title: Astronomy and Astrophysics

Vol. 448

Pages: 907-U27

ISSN: 0004-6361

Publisher: EDP Sciences

Indexing

ISI Web of Knowledge - 32 Citations

Scopus - 30 Citations

Other information

Authenticus ID: P-004-MVH

DOI: 10.1051/0004-6361:20053602

Abstract (EN): We present the gas-phase oxygen abundance (O/H) for a sample of 131 star-forming galaxies at intermediate redshifts (0.2 < z < 1.0). The sample selection, the spectroscopic observations ( mainly with VLT/FORS) and associated data reduction, the photometric properties, the emission-line measurements, and the spectral classification are fully described in a companion paper ( Paper I). We use two methods to estimate the O/H abundance ratio: the "standard" R-23 method which is based on empirical calibrations, and the CL01 method which is based on grids of photo-ionization models and on the fitting of emission lines. For most galaxies, we have been able to solve the problem of the metallicity degeneracy between the high- and low-metallicity branches of the O/H vs. R-23 relationship using various secondary indicators. The luminosity - metallicity (L - Z) relation has been derived in the B- and R-bands, with metallicities derived with the two methods (R-23 and CL01). In the analysis, we first consider our sample alone and then a larger one which includes other samples of intermediate-redshift galaxies drawn from the literature. The derived L - Z relations at intermediate redshifts are very similar ( same slope) to the L - Z relation obtained for the local universe. Our sample alone only shows a small, not significant, evolution of the L-Z relation with redshift up to z similar to 1.0. We only find statistical variations consistent with the uncertainty in the derived parameters. Including other samples of intermediate-redshift galaxies, we find however that galaxies at z similar to 1 appear to be metal-deficient by a factor of similar to 3 compared with galaxies in the local universe. For a given luminosity, they contain on average about one third of the metals locked in local galaxies.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 21