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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
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
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