New abundance determinations in z < 1.5 QSO absorbers: seven sub-DLAs and one DLA

作者：Meiring Joseph D^*; Lauroesch James T; Kulkarni Varsha P; Peroux Celine; Khare Pushpa; York Donald G; Crotts Arlin P S

来源：Monthly Notices of the Royal Astronomical Society, 2007, 376(2): 557-572.

DOI：10.1111/j.1365-2966.2007.11521.x

• ISM : abundances
• quasars : absorption lines

We present chemical abundance measurements from high-resolution observations of seven subdamped Ly alpha (sub-DLA) absorbers and one DLA system at z < 1.5. Three of these objects have high metallicity, with near or supersolar Zn abundance. Grids of CLOUDY models for each system were constructed to look for possible ionization effects in these systems. For the systems in which we could constrain the ionization parameter, we find that the ionization corrections as predicted by the CLOUDY models are generally small and within the typical error bars (similar to 0.15 dex), in general agreement with previous studies. The Al III to Al II ratio for these and other absorbers from the literature are compared, and we find that while the sub-DLAs have a larger scatter in the Al in to Al it ratios than the DLAs, there appears to be little correlation between the ratio and N-HI. The relationship between the metallicity and the velocity width of the profile for these systems is investigated. We show that the sub-DLAs that have been observed to date follow a similar trend as DLA absorbers, with the more metal rich systems exhibiting large velocity widths. We also find that the systems at the upper edge of this relationship with high metallicities and large velocity widths are more likely to be sub-DLAs than DLA absorbers, perhaps implying that the sub-DLA absorbers are more representative of massive galaxies.

• 出版日期2007-4-1
• 单位西北大学