J/AJ/130/1345 Optical-infrared colors of CORALS QSOs (Ellison+, 2005)
The optical-infrared colors of CORALS QSOs: searching for dust reddening
associated with high-redshift damped Lyα systems.
Ellison S.L., Hall P.B., Lira P.
<Astron. J., 130, 1345-1357 (2005)>
=2005AJ....130.1345E 2005AJ....130.1345E
ADC_Keywords: QSOs ; Redshifts ; Interstellar medium ; Photometry ; Abundances
Keywords: dust, extinction - galaxies: high-redshift - ISM: general -
quasars: absorption lines
Abstract:
The presence of dust in quasar absorbers, such as damped Lyα (DLA)
systems, may cause the background QSO to appear reddened. We
investigate the extent of this potential reddening by comparing the
optical-to-infrared colors of QSOs with and without intervening
absorbers. Our QSO sample is based on the Complete Optical and Radio
Absorption Line System (CORALS) survey of Ellison and coworkers. The
CORALS data set consists of 66 radio-selected QSOs at zem≥2.2 with
complete optical identifications. We have obtained near-simultaneous
B- and K-band magnitudes for a subset of the CORALS sample and
supplemented our observations with further measurements published in
the literature. In total, we have B-K colors for 42 of the 66 QSOs, of
which 14 have intervening DLA systems. To account for redshift-related
color changes, the B-K colors are normalized using the Sloan Digital
Sky Survey QSO composite.
Description:
Since flat-spectrum radio-loud QSOs (RLQs) are highly variable, it is
important to obtain optical and IR data from near-simultaneous epochs.
We achieved this by using the optical (SuSI2) and IR (SofI) imagers on
the New Technology Telescope (NTT) at La Silla Observatory. Our data
were obtained during two runs in 2003 October and 2004 March.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 64 66 CORALS QSO magnitudes
table3.dat 54 42 Normalized colors and intervening absorber properties
for CORALS QSOs with near-simultaneous B-K colors
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See also:
J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- QSO The QSO name
11- 15 F5.3 --- z Redshift from emission lines
17- 20 F4.1 mag Bjmag ? The UKST Bj magnitude
22- 26 F5.2 mag Bmag ? The B band magnitude
28- 31 F4.2 mag e_Bmag ? Error in Bmag
33- 37 F5.2 mag Vmag ? The V band magnitude
39- 42 F4.2 mag e_Vmag ? Error in Vmag
44- 48 F5.2 mag Ksmag ? The Ks band magnitude
50- 53 F4.2 mag e_Ksmag ? Error in Ksmag
55- 63 A9 --- Ref Photometry reference (1)
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Note (1): Photometry reference: This work, or FWW00 = Francis, Whiting & Webster
(2000PASA...17...56F 2000PASA...17...56F).
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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- 9 A9 --- QSO QSO name
11- 15 F5.3 --- zem ? Redshift from emission lines
17- 21 F5.3 --- zabs ? Absorption redshift
23- 27 F5.2 [cm-2] N(HI) ? HI column density
30- 34 F5.2 mag B-K ? Normalized (B-K) color index
36- 39 F4.2 mag e_B-K ? Error in B-K
41 A1 --- l_[Zn/H] Upper limit flag on [Zn/H]
42- 46 F5.2 [Sun] [Zn/H] ? [Zn/H] abundance
48- 52 F5.2 [Sun] [Fe/H] ? [Fe/H] abundance
54 I1 --- Ref ? Abundance origin (1)
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Note (1): Abundance references, defined as follows:
1 = Akerman et al. 2005A&A...440..499A 2005A&A...440..499A
2 = Ellison & Lopez 2001A&A...380..117E 2001A&A...380..117E
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 24-Feb-2006