J/A+A/410/33 MgII/FeII absorbers in 2dF-quasar survey (Menard+, 2003)
Investigating lensing by absorbers in the 2dF-quasar survey.
Menard B., Peroux C.
<Astron. Astrophys. 410, 33 (2003)>
=2003A&A...410...33M 2003A&A...410...33M
ADC_Keywords: QSOs ; Redshifts ; Equivalent widths
Keywords: cosmology: observations - quasars: absorption lines -
cosmology: gravitational lensing - surveys
Abstract:
We use the first data release of the 2-degree Field quasar survey
(Cat. VII/223) to investigate the effect of gravitational
magnification by foreground absorbing systems on background quasars.
We select two populations of quasars from this sample: one with strong
MgII/FeII absorbers and one without. The selection is done in such a
way that the two populations have the same redshift distribution and
the absorber detection procedure discards possible biases with quasar
magnitude.
Description:
The first data release of the 2QZ (Cat. VII/223) contains over ten
thousand low resolution quasar spectra, taken with the 2-degree Field
instrument at the Anglo-Australian Telescope in the range
3700-7500Å. Quasar candidates with 18.25<bJ<20.85 were selected
from a single homogeneous color-based catalogue from APM (Automatic
Plate Measuring, Cat. I/267) measurements of UK Schmidt photographic
material. Note that the corresponding u- and r-band quasar catalogues
are therefore not complete. In our study we will use the absorber
catalogue compiled by Outram et al. (2001, Cat. J/MNRAS/328/805).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea2.dat 42 110 Detailed list of the quasars with an absorber
used in our analysis.
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See also:
VII/223 : The 2dF QSO Redshift Survey. V. The 10k catalogue (Croom+ 2001)
I/267 : The APM-North Catalogue (McMahon+, 2000)
J/MNRAS/328/805 : The 2dF QSO Redshift Survey. VIII (Outram+, 2001)
Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- QSO Quasar designation (JHHMMSS.s+DDMMSS)
18- 22 F5.3 --- zem Emission redshift
24- 25 I2 --- S/N Signal-to-noise ratio
27- 31 F5.3 --- zabs Absorption redshift
33- 36 F4.2 0.1nm W0 Rest equivalent width of the MgII doublets
37 A1 --- n_W0 [ab] Note on W0 (1)
39- 42 A4 --- Flag Flags (2)
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Note (1): Note on W0 as follows:
a = Rest equivalent width of FeII λ=2600Å
(MgII blended with sky lines)
b = Rest equivalent width of MgII λ=2796Å only
Note (2): Flags as follows:
A = presence of two absorbers in the quasar spectrum
B = presence of two absorbers in the quasar spectrum and
one of these two absorbers has z(abs) close to z(QSO)
R1 = Quasar not detected in the r-band
R2 = Quasar has an absorber escape velocity smaller than 3000km/s.
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 17-Nov-2003