J/ApJ/661/88 Zn measurements in sub-DLAs and DLAs QSOs (Kulkarni+, 2007)
The role of sub-damped Lyα absorbers in the cosmic evolution of metals.
Kulkarni V.P., Khare P., Peroux C., York D.G., Lauroesch J.T., Meiring J.D.
<Astrophys. J., 661, 88-94 (2007)>
=2007ApJ...661...88K 2007ApJ...661...88K
ADC_Keywords: QSOs ; Redshifts ; Spectroscopy
Keywords: ISM: abundances - quasars: absorption lines
Abstract:
Observations of low mean metallicity of damped Lyα (DLA) quasar
absorbers at all redshifts studied appear to contradict the
predictions for the global mean interstellar metallicity in galaxies
from cosmic chemical evolution models. On the other hand, a number of
metal-rich sub-DLA systems have been identified recently, and the
fraction of metal-rich sub-DLAs appears to be considerably larger than
that of metal-rich DLAs, especially at z<1.5. In view of this, here we
investigate the evolution of metallicity in sub-DLAs. We find that the
mean Zn metallicity of the observed sub-DLAs may be higher than that
of the observed DLAs, especially at low redshifts, reaching a
near-solar level at z≲1. This trend does not appear to be an artifact
of sample selection, the use of Zn, the use of NHI weighting, or
observational sensitivity.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 82 149 Zn Measurements in Sub-DLAs and DLAs
refs.dat 176 37 References
--------------------------------------------------------------------------------
See also:
J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)
J/A+A/478/701 : Color excess of SDSS QSOs with DLA systems (Vladilo+, 2008)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Type The damped Lyman-alpha quasar absorber type
9- 17 A9 --- Name Quasar identification
19- 23 A5 --- Ref Reference code, in refs.dat file
25- 30 F6.4 --- z Redshift from absorption lines
32 A1 --- l_[Zn/H] Limit flag on [Zn/H]
33- 37 F5.2 [Sun] [Zn/H] Log of the Zn/H number abundance
39- 43 F5.2 10-20/cm2 NHI The HI column density
45- 49 F5.2 10-20/cm2 e_NHI Uncertainty in NHI
51 A1 --- l_NZnII Limit flag on NZnII
52- 56 F5.2 10-12/cm2 NZnII The ZnII column density
58- 61 F4.2 10-12/cm2 e_NZnII ? Uncertainty in NNZnII
63- 67 F5.2 [Sun] [X/H] ? Abundance of S or Si (1)
69- 70 A2 --- n_[X/H] Indicates element "X" in [X/H] (1)
74- 77 F4.2 0.1nm EW2796 ? Equivalent width of MgII (2796Å)
79- 82 F4.2 0.1nm EW2600 ? Equivalent width of line at 2600Å
--------------------------------------------------------------------------------
Note (1): Abundances of S or Si if available, are listed for sub-DLAs
in cases with Zn upper limits.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 48 A25 --- Aut Author's name
50-176 A127 --- Com Comments
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 21-Mar-2009