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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
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:
FileName Lrecl Records Explanations
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
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
Bytes Format Units Label Explanations
1- 19 A19 --- Name QSO identification ( or (1) 21- 25 F5.3 --- zabs Absorption redshift 27- 31 F5.2 [cm-2] logNHI Log of the HI column density
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). We caution that many of these will not be bona-fide DLAs.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
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)
Byte-by-byte Description of file: table13.dat
Bytes Format Units Label Explanations
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]
Byte-by-byte Description of file: table14.dat
Bytes Format Units Label Explanations
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
Global notes: Note (G1): In tables 2, 13 and 14, SDSS0751+4516 is a misprint for SDSS0751+3120; corrected at CDS.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 05-Jul-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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