J/ApJ/714/1521 Spectroscopy of galaxies around distant QSOs (Chen+, 2010)
An empirical characterization of extended cool gas around galaxies using Mg II
absorption features.
Chen H.-W., Helsby J.E., Gauthier J.-R., Shectman S.A., Thompson I.B.,
Tinker J.L.
<Astrophys. J., 714, 1521-1541 (2010)>
=2010ApJ...714.1521C 2010ApJ...714.1521C
ADC_Keywords: Galaxies, spectra ; Equivalent widths ; Photometry, SDSS ;
Redshifts ; QSOs
Keywords: cosmology: observations - intergalactic medium -
quasars: absorption lines
Abstract:
We report results from a survey of MgII absorbers in the spectra of
background quasi-stellar objects (QSOs) that are within close angular
distances to a foreground galaxy at z<0.5, using the Magellan
Echellette Spectrograph. We have established a spectroscopic sample of
94 galaxies at a median redshift of =0.24 in fields around 70
distant background QSOs (zQSO>0.6), 71 of which are in an "isolated"
environment with no known companions and located at ρ≲120h-1kpc
from the line of sight of a background QSO. The rest-frame absolute
B-band magnitudes span a range from MB-5logh=-16.4 to
MB-5logh=-21.4 and rest-frame BAB-RAB colors range from
BAB-RAB∼0 to BAB-RAB∼1.5. Of these "isolated" galaxies, we
find that 47 have corresponding MgII absorbers in the spectra of
background QSOs and rest-frame absorption equivalent width
Wr(2796)=0.1-2.34Å, and 24 do not give rise to MgII absorption to
sensitive upper limits.
Description:
We have obtained optical spectra of 89 photometrically selected
SDSS-DR6 galaxies, using the Double Imaging Spectrograph (DIS) on the
3.5m telescope at the Apache Point Observatory and Magellan Echellette
Spectrograph (MagE) on the Magellan Clay Telescope at the Las Campanas
Observatory. Long-slit spectra of 41 galaxies were obtained using DIS
over the period from 2008 October through 2009 June. Optical spectra
of 48 galaxies were obtained using MagE in 2008 September, 2009
February, 2009 March, and 2009 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 94 Summary of faint galaxy spectroscopy
table2.dat 83 70 Summary of the MagE spectroscopic observations
of SDSS QSOs
table3.dat 90 94 Galaxies and absorption systems
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See also:
II/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
J/ApJS/194/42 : SDSS-DR3 MgII-based black hole masses (Rafiee+, 2011)
J/ApJ/698/819 : MgII and LRGs cross-correlation analysis (Lundgren+, 2009)
J/ApJ/679/239 : Associated MgII absorbers (Vanden+, 2008)
J/ApJ/639/766 : SDSS-DR3 strong MgII absorbers (Prochter+, 2006)
J/MNRAS/371/495 : Catalogue of 1806 MgII absorbers from SDSS (Bouche+, 2006)
J/MNRAS/354/L25 : MgII absorbers in SDSS QSOs (Bouche+, 2004)
J/AJ/106/848 : QSO MgII absorption line systems (Drinkwater+, 1993)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
5- 24 A20 --- SDSS SDSS-DR6 designation (JHHMMSS.ss+DDMMSS.ss)
26- 27 I2 h RAh Hour of right ascension (J2000)
29- 30 I2 min RAm Minute of right ascension (J2000)
32- 36 F5.2 s RAs Second of right ascension (J2000)
38 A1 --- DE- Sign of declination (J2000)
39- 40 I2 deg DEd Degree of declination (J2000)
42- 43 I2 arcmin DEm Arcminute of declination (J2000)
45- 49 F5.2 arcsec DEs Arcsecond of declination (J2000)
51- 54 F4.2 --- zph ? Photometric redshift
56- 59 F4.2 --- e_zph ? zph uncertainty
61- 64 F4.1 mag r'mag r'-band magnitude
66- 69 A4 --- Inst [DIS /MagE/SDSS] Instrument used (1)
71 I1 --- mult ? Exposure multiplicator
72 A1 --- --- [x]
73- 76 I4 s Exp ? Exposure time
77 A1 --- --- [+]
78 I1 --- mult2 ? Second exposure multiplicator
79 A1 --- --- [x]
80- 83 I4 s Exp2 ? Additional exposure time
85- 94 A10 "YYYY/MM/DD" Date UT date of observation
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Note (1): Instruments are:
DIS = Double Imaging Spectrograph on the 3.5m telescope at Apache Point
MagE = Magellan Echellette Spectrograph on the Magellan Clay Telescope
at Las Campanas
SDSS = spectrum from SDSS
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
5- 24 A20 --- SDSS SDSS-DR6 designation (JHHMMSS.ss+DDMMSS.ss)
26- 27 I2 h RAh Hour of right ascension (J2000)
29- 30 I2 min RAm Minute of right ascension (J2000)
32- 36 F5.2 s RAs Second of right ascension (J2000)
38 A1 --- DE- Sign of declination (J2000)
39- 40 I2 deg DEd Degree of declination (J2000)
42- 43 I2 arcmin DEm Arcminute of declination (J2000)
45- 49 F5.2 arcsec DEs Arcsecond of declination (J2000)
51- 54 F4.2 --- z ? QSO redshift
56- 60 F5.2 mag u'mag u'-band magnitude
62 I1 --- mult ? Exposure multiplicator
63 A1 --- --- [x]
64- 67 I4 --- Exp ? Exposure time
68 A1 --- --- [+]
69- 72 I4 --- Exp2 ? Additional exposure time
74- 83 A10 "YYYY/MM/DD" Date UT date of observation
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Set [G /GrG] GrG: "Group" galaxies vs "isolated"
environment
5- 8 A4 --- --- [SDSS]
9- 28 A20 --- SDSS SDSS-DR6 designation (JHHMMSS.ss+DDMMSS.ss)
30- 34 F5.1 arcsec dRA Right ascension offset from the QSO
36- 40 F5.1 arcsec dDE Declination offset from the QSO
42- 47 F6.4 --- zgal Galaxy redshift (spectroscopic)
49- 53 F5.1 kpc rho Impact parameter (ρ) in h-1*kpc units
55- 59 F5.2 mag r'mag Apparent r'-band magnitude
61- 66 F6.2 mag MB Absolute B-band magnitude (MB-5logh)
68- 72 F5.2 mag B-R BAB-RAB color index
74- 79 F6.4 --- zabs ? Redshift of the corresponding MgII
absorption feature
81 A1 --- l_W2796 Limit flag on W2796
82- 85 F4.2 0.1nm W2796 ? Absorption equivalent width of the
corresponding MgII absorption feature
87- 90 F4.2 0.1nm e_W2796 ? W2796 uncertainty
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 25-Apr-2012