3 research outputs found
The mass-metallicity relation at z~0.7
The ISM metallicity and the stellar mass are examined in a sample of 66
galaxies at 0.4<z<1, selected from the Gemini Deep Deep Survey (GDDS) and the
Canada-France Redshift Survey (CFRS). We observe a mass-metallicity relation
similar to that seen in z~0.1 SDSS galaxies, but displaced towards higher
masses and/or lower metallicities. Using this sample, and a small sample of
z~2.3 LBGs, a redshift dependent mass-metallicity relation is proposed which
describes the observed results.Comment: To appear in the proceedings of the conference "The Spectral Energy
Distribution of Gas-Rich Galaxies", eds. C.C. Popescu & R.J. Tuffs
(Heidelberg, October 2004
Bioavailability, distribution and clearance of tracheally-instilled and gavaged uncoated or silica-coated zinc oxide nanoparticles
The Gemini Deep Deep Survey: II. Metals in Star-Forming Galaxies at Redshift 1.3
The goal of the Gemini Deep Deep Survey (GDDS) is to study an unbiased sample of K<20.6 galaxies in the redshift range 0.81.3. The selected objects have colors typical of irregular and Sbc galaxies. Strong [OII] emission indicates high star formation activity in the HII regions (SFR~13-106 M_sun/yr). The high S/N composite spectrum shows strong ISM MgII and FeII absorption, together with weak MnII and MgI lines. The FeII column density, derived using the curve of growth analysis, is logN_FeII = 15.54^{+0.23}_{-0.13}. This is considerably larger than typical values found in damped Ly-alpha systems (DLAs) along QSO sight lines, where only 10 out of 87 (~11%) have logN_FeII > 15.2. High FeII column densities are observed in the z=2.72 Lyman break galaxy cB58 (logN_FeII ~ 15.25) and in gamma-ray burst host galaxies (logN_FeII ~ 14.8-15.9). Given our measured FeII column density and assuming a moderate iron dust depletion (delta_Fe ~ 1 dex), we derive an optical dust extinction A_V ~ 0.6. If the HI column density is log N(HI)<21.7 (as in 98% of DLAs), then the mean metallicity is Z/Z_sun > 0.2. The high completeness of the GDDS sample implies that these results are typical of star-forming galaxies in the 1</z<2.0.