%0 Generic %1 som2015hubble %A Som, Debopam %A Kulkarni, Varsha P. %A Meiring, Joseph %A York, Donald G. %A Péroux, Celine %A Lauroesch, James T. %A Aller, Monique C. %A Khare, Pushpa %D 2015 %K low-z sub-dla %T Hubble Space Telescope Observations of Sub-Damped Lyman-alpha Absorbers at z < 0.5, and Implications for Galaxy Chemical Evolution %U http://arxiv.org/abs/1502.01989 %X We report observations of four sub-damped Lyman-alpha (sub-DLA) quasar absorbers at z<0.5 obtained with the Hubble Space Telescope Cosmic Origins Spectrograph. We measure the available neutrals or ions of C, N, O, Si, P, S, Ar, Mn, Fe, and/or Ni. Our data have doubled the sub-DLA metallicity samples at z<0.5 and improved constraints on sub-DLA chemical evolution. All four of our sub-DLAs are consistent with near-solar or super-solar metallicities and relatively modest ionization corrections; observations of more lines and detailed modeling will help to verify this. Combining our data with measurements from the literature, we confirm previous suggestions that the N(HI)-weighted mean metallicity of sub-DLAs exceeds that of DLAs at all redshifts studied, even after making ionization corrections for sub-DLAs. The absorber toward PHL 1598 shows significant dust depletion. The absorbers toward PHL 1226 and PKS 0439-433 show the S/P ratio consistent with solar, i.e., they lack a profound odd-even effect. The absorber toward Q0439-433 shows super-solar Mn/Fe. For several sub-DLAs at z<0.5, N/S is below the level expected for secondary N production, suggesting a delay in the release of the secondary N or a tertiary N production mechanism. We constrain the electron density using Si II* and C II* absorption. We also report different metallicity vs. Delta V_90 relations for sub-DLAs and DLAs. For two sub-DLAs with detections of emission lines from the underlying galaxies, our measurements of the absorption-line metallicities are consistent with the emission-line metallicities, suggesting that metallicity gradients are not significant in these galaxies.

@misc{som2015hubble, abstract = {We report observations of four sub-damped Lyman-alpha (sub-DLA) quasar absorbers at z<0.5 obtained with the Hubble Space Telescope Cosmic Origins Spectrograph. We measure the available neutrals or ions of C, N, O, Si, P, S, Ar, Mn, Fe, and/or Ni. Our data have doubled the sub-DLA metallicity samples at z<0.5 and improved constraints on sub-DLA chemical evolution. All four of our sub-DLAs are consistent with near-solar or super-solar metallicities and relatively modest ionization corrections; observations of more lines and detailed modeling will help to verify this. Combining our data with measurements from the literature, we confirm previous suggestions that the N(HI)-weighted mean metallicity of sub-DLAs exceeds that of DLAs at all redshifts studied, even after making ionization corrections for sub-DLAs. The absorber toward PHL 1598 shows significant dust depletion. The absorbers toward PHL 1226 and PKS 0439-433 show the S/P ratio consistent with solar, i.e., they lack a profound odd-even effect. The absorber toward Q0439-433 shows super-solar Mn/Fe. For several sub-DLAs at z<0.5, [N/S] is below the level expected for secondary N production, suggesting a delay in the release of the secondary N or a tertiary N production mechanism. We constrain the electron density using Si II* and C II* absorption. We also report different metallicity vs. Delta V_90 relations for sub-DLAs and DLAs. For two sub-DLAs with detections of emission lines from the underlying galaxies, our measurements of the absorption-line metallicities are consistent with the emission-line metallicities, suggesting that metallicity gradients are not significant in these galaxies.}, added-at = {2015-02-09T10:16:15.000+0100}, author = {Som, Debopam and Kulkarni, Varsha P. and Meiring, Joseph and York, Donald G. and Péroux, Celine and Lauroesch, James T. and Aller, Monique C. and Khare, Pushpa}, biburl = {https://www.bibsonomy.org/bibtex/259a74d4eb7f578ac855a406ae775c939/miki}, description = {[1502.01989] Hubble Space Telescope Observations of Sub-Damped Lyman-alpha Absorbers at z &lt; 0.5, and Implications for Galaxy Chemical Evolution}, interhash = {84c600ae19724bc8580b460ccab417c1}, intrahash = {59a74d4eb7f578ac855a406ae775c939}, keywords = {low-z sub-dla}, note = {cite arxiv:1502.01989Comment: 77 pages, 13 figures; submitted to The Astrophysical Journal (revised version)}, timestamp = {2015-02-09T10:16:15.000+0100}, title = {Hubble Space Telescope Observations of Sub-Damped Lyman-alpha Absorbers at z < 0.5, and Implications for Galaxy Chemical Evolution}, url = {http://arxiv.org/abs/1502.01989}, year = 2015 }