J/ApJ/721/1 Keck ESI observations of Lyα systems (Penprase+, 2010)
Keck Echellette Spectrograph and Imager observations of metal-poor damped
Lyα systems.
Penprase B.E., Prochaska J.X., Sargent W.L.W., Toro-Martinez I.,
Beeler D.J.
<Astrophys. J., 721, 1-25 (2010)>
=2010ApJ...721....1P 2010ApJ...721....1P
ADC_Keywords: Abundances ; QSOs ; Redshifts ; Spectroscopy
Keywords: galaxies: ISM - quasars: absorption lines -
quasars: individual (SDSS0814+5029, SDSS1001+0343)
Abstract:
We present the first results from a survey of SDSS quasars selected
for strong HI damped Lyα (DLA) absorption with corresponding low
equivalent width absorption from strong low-ion transitions (e.g.,
CIIλ1334 and SiIIλ1260). These metal-poor DLA candidates
were selected from the SDSS fifth release quasar spectroscopic
database, and comprise a large new sample for probing low-metallicity
galaxies. Medium-resolution echellette spectra from the Keck
Echellette Spectrograph and Imager spectrograph for an initial sample
of 35 systems were obtained to explore the metal-poor tail of the DLA
distribution and to investigate the nucleosynthetic patterns at these
metallicities. We have estimated saturation corrections for the
moderately underresolved spectra, and systems with very narrow Doppler
parameters (b≤5km/s) will likely have underestimated abundances. For
those systems with Doppler parameters b>5km/s, we have measured
low-metallicity DLA gas with [X/H]←2.4 for at least one of C, O, Si,
or Fe. Assuming non-saturated components, we estimate that several DLA
systems have [X/H]←2.8, including five DLA systems with both low
equivalent widths and low metallicity in transitions of both CII and
OI. All of the measured DLA metallicities, however, exceed or are
consistent with a metallicity of at least 1/1000 of solar, regardless
of the effects of saturation in our spectra.
Description:
The data for this paper were acquired during two observing runs at the
Keck II telescope in 2007 March and 2008 May.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 31 405 SDSS-DR5 metal-poor DLA candidates
table2.dat 57 44 Targets observed, magnitudes, and exposure times
table13.dat 85 35 Elemental abundances for DLA systems
table14.dat 52 41 Column densities for the species CIV and SiIV
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See also:
J/ApJ/675/1002 : Proximate damped Lyα systems in SDSS-DR5 (Prochaska+,
2008)
J/ApJ/683/321 : Metallicities of GRB, DLA, and Lyα galaxies (Fynbo+,
2008)
J/A+A/478/701 : Color excess of SDSS QSOs with DLA systems (Vladilo+, 2008)
J/ApJS/171/29 : UCSD/Keck DLA Database (Prochaska+, 2007)
J/ApJ/635/123 : The SDSS-DR3 damped Lyα survey (Prochaska+, 2005)
J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)
J/ApJ/543/552 : z>3 damped Lyα absorption systems (Storrie-Lombardi+,
2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name QSO identification (JHMMSS.ss+DDMMSS or
JHHMMSS.ss+DDMMSS) (1)
21- 25 F5.3 --- zabs Absorption redshift
27- 31 F5.2 [cm-2] logNHI Log of the HI column density
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Note (1): List of all candidate metal-poor DLAs flagged by Prochaska and
collaborators from their analysis of the SDSS-DR5 (See
Cat. J/ApJ/635/123 and 2009ApJ...696.1543P 2009ApJ...696.1543P). We caution that
many of these will not be bona-fide DLAs.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
5- 13 A9 --- QSO Quasar designation (HHMM+DDMM; J2000) (G1)
15- 19 F5.3 --- zDLA DLA redshift
21- 22 I2 h RAh Hour of right ascension (J2000)
24- 25 I2 min RAm Minute of right ascension (J2000)
27- 31 F5.2 s RAs Second of right ascension (J2000)
33 A1 --- DE- Sign of declination (J2000)
34- 35 I2 deg DEd Degree of declination (J2000)
37- 38 I2 arcmin DEm Arcminute of declination (J2000)
40- 41 I2 arcsec DEs Arcsecond of declination (J2000)
43- 47 F5.2 mag Rmag R-band magnitude
49- 52 I4 s Exp08 ? Exposure time (2008)
54- 57 I4 s Exp07 ? Exposure time (2007)
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Byte-by-byte Description of file: table13.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
5- 13 A9 --- QSO Quasar designation (HHMM+DDMM; J2000) (G1)
15- 20 F6.4 --- zDLA DLA redshift
22- 26 F5.2 [cm-2] logNHI Log of HI column density
28- 31 F4.2 [cm-2] e_logNHI logNHI uncertainty
33 A1 --- l_[C/H] Limit flag on [C/H]
34- 38 F5.2 [-] [C/H] ? Abundance [C/H]
40 A1 --- f_[C/H] [abc] Flag on [C/H]
42 A1 --- l_[O/H] Limit flag on [O/H]
43- 47 F5.2 [-] [O/H] ? Abundance [O/H]
49 A1 --- f_[O/H] [abc] Flag on [O/H]
51 A1 --- l_[Si/H] Limit flag on [Si/H]
52- 56 F5.2 [-] [Si/H] ? Abundance [Si/H]
58 A1 --- f_[Si/H] [abc] Flag on [Si/H]
60 A1 --- l_[Al/H] Limit flag on [Al/H]
61- 65 F5.2 [-] [Al/H] ? Abundance [Al/H]
67 A1 --- f_[Al/H] [abc] Flag on [Al/H]
69 A1 --- l_[Fe/H] Limit flag on [Fe/H]
70- 74 F5.2 [-] [Fe/H] ? Abundance [Fe/H]
76 A1 --- f_[Fe/H] [abc] Flag on [Fe/H]
78 A1 --- l_[Mg/H] Limit flag on [Mg/H]
79- 83 F5.2 [-] [Mg/H] ? Abundance [Mg/H]
85 A1 --- f_[Mg/H] [abc] Flag on [Mg/H]
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Byte-by-byte Description of file: table14.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
5- 13 A9 --- QSO Quasar designation (HHMM+DDMM; J2000) (G1)
15- 20 F6.4 --- zDLA DLA redshift
22- 26 F5.2 [cm-2] logNHI Log of HI column density
28 A1 --- l_logNCIV Limit flag on logNCIV
29- 33 F5.2 [cm-2] logNCIV Log of CIV column density
35- 39 F5.3 [cm-2] e_logNCIV ? logNCIV uncertainty
41 A1 --- l_logNSiIV Limit flag on logNSiIV
42- 46 F5.2 [cm-2] logNSiIV ? Log of SiIV column density
48- 52 F5.3 [cm-2] e_logNSiIV ? logNSiIV uncertainty
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Global notes:
Note (G1):
In tables 2, 13 and 14, SDSS0751+4516 is a misprint for SDSS0751+3120;
corrected at CDS.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 05-Jul-2012