J/ApJ/778/127 UKIDSS+FIRST+SDSS red QSOs candidates (Glikman+, 2013)
Dust reddened quasars in FIRST and UKIDSS: beyond the tip of the iceberg.
Glikman E., Urrutia T., Lacy M., Djorgovski S.G., Urry M., Croom S.,
Schneider D.P., Mahabal A., Graham M., Ge J.
<Astrophys. J., 778, 127 (2013)>
=2013ApJ...778..127G 2013ApJ...778..127G
ADC_Keywords: QSOs ; Redshifts ; Photometry, infrared ; Radio sources ;
Photometry, SDSS ; Reddening ; Surveys
Keywords: dust, extinction; galaxies: evolution; quasars: general; surveys
Abstract:
We present the results of a pilot survey to find dust-reddened quasars
by matching the Faint Images of the Radio Sky at Twenty-Centimeters
(FIRST) radio catalog to the UKIDSS near-infrared survey and using
optical data from Sloan Digital Sky Survey to select objects with very
red colors. The deep K-band limit provided by UKIDSS allows for
finding more heavily reddened quasars at higher redshifts as compared
with previous work using FIRST and Two Micron All Sky Survey (2MASS).
We selected 87 candidates with K≤17.0 from the UKIDSS Large Area
Survey (LAS) First Data Release (DR1), which covers 190deg2. These
candidates reach up to ∼1.5mag below the 2MASS limit and obey the
color criteria developed to identify dust-reddened quasars. We have
obtained 61 spectroscopic observations in the optical and/or
near-infrared, as well as classifications in the literature, and have
identified 14 reddened quasars with E(B-V)>0.1, including 3 at z>2. We
study the infrared properties of the sample using photometry from the
Wide-Field Infrared Survey Explorer and find that infrared colors
improve the efficiency of red quasar selection, removing many
contaminants in an infrared-to-optical color-selected sample alone.
The highest-redshift quasars (z≳2) are only moderately reddened, with
E(B-V)∼0.2-0.3. We find that the surface density of red quasars rises
sharply with faintness, comprising up to 17% of blue quasars at the
same apparent K-band flux limit. We estimate that to reach more
heavily reddened quasars (i.e., E(B-V)≳0.5) at z>2 and a depth of
K=17, we would need to survey at least ∼2.5 times more area.
Description:
We obtained 63 spectroscopic identifications of our 87 candidates.
These identifications were primarily determined from 44 near-infrared
spectra acquired with the TripleSpec spectrograph on the Palomar Hale
telescope during five observing runs between 2008 August and 2013
April.
An additional 15 optical spectra were obtained from the SDSS. A total
of 11 spectra came from the AAOmega-UKIDSS-SDSS Survey (AUS; S. Croom
et al., in preparation) in the Stripe-82 region, an additional three
spectra were obtained with the Low Resolution Imaging Spectrograph
(LRIS) on the W. M. Keck telescope on 2012 October 15, and one object
was identified as a luminous red galaxy (LRG) by the 2dF-SDSS LRG and
QSO survey (2SLAQ; Cannon et al. 2006, J/MNRAS/372/425; superseded by
J/MNRAS/392/19). In addition, two sources have photometric redshifts
determined from the Red-Sequence Cluster Survey (Hsieh et al. 2005,
J/ApJS/158/161).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 129 87 UKFS (UKIDSS+FIRST+SDSS) red quasar candidates
table2.dat 80 20 Reddening properties of UKFS red quasars
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See also:
VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)
J/ApJ/757/51 : FIRST-2MASS dust-reddened QSO spectra (Glikman+, 2012)
J/MNRAS/424/2876 : Large area KX quasar catalogue (Maddox+, 2012)
J/AJ/144/49 : Quasars from SDSS-DR7, WISE and UKIDSS surveys (Wu+, 2012)
J/AJ/141/105 : NIR-matched quasar catalog (Peth+, 2011)
J/ApJ/710/1498 : QSO luminosity function at z∼4 (Glikman+, 2010)
J/MNRAS/401/1429 : WiggleZ dark energy survey (DR1) (Drinkwater+, 2010)
J/ApJ/698/1095 : The FIRST-2MASS red QSO survey. II. (Urrutia+, 2009)
J/ApJS/181/233 : Catalog of merging galaxies (Hwang+, 2009)
J/ApJ/680/130 : Mid-IR colors of AGNs in the MUSYC ECDF-S (Cardamone+, 2008)
J/MNRAS/386/1605 : Luminous K-band selected QSOs from UKIDSS (Maddox+, 2008)
J/MNRAS/383/1513 : 2MASS, SDSS and FIRST fluxes of QSOs (Labita+, 2008)
J/ApJ/667/673 : FIRST-2MASS red quasar survey (Glikman+, 2007)
J/ApJ/666/806 : SED of Spitzer quasars (QUEST) (Netzer+, 2007)
J/ApJ/663/81 : SED of hard X-ray selected AGN in XMDS (Polletta+, 2007)
J/AJ/133/186 : Optical spectroscopy of luminous AGNs and QSOs (Lacy+, 2007)
J/MNRAS/372/425 : 2dF-SDSS Luminous Red Galaxy Survey, 2SLAQ (Cannon+, 2006)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/ApJ/642/673 : IR-selected obscured AGN candidates (Polletta+, 2006)
J/ApJ/640/579 : Near-infrared spectra of 27 SDSS quasars (Glikman+, 2006)
J/ApJS/158/161 : Photometric redshift catalog from the RCS (Hsieh+, 2005)
J/ApJ/607/60 : FIRST-2MASS faint sources (Glikman+, 2004)
J/ApJS/135/227 : The FIRST bright quasar survey. III. (Becker+, 2001)
J/ApJS/126/133 : The FIRST bright quasar survey. II. (White+, 2000)
J/AJ/112/407 : The FIRST bright QSO survey (Gregg+, 1996)
J/ApJ/269/352 : Quasar evolution (Schmidt+, 1983)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Hour of Right Ascension (J2000)
4- 5 I2 min RAm Minute of Right Ascension (J2000)
7- 11 F5.2 s RAs Second of Right Ascension (J2000)
13 A1 --- DE- Sign of the Declination (J2000)
14- 15 I2 deg DEd Degree of Declination (J2000)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000)
20- 23 F4.1 arcsec DEs Arcsecond of Declination (J2000)
25 A1 --- l_rmag Limit flag on rmag
26- 31 F6.2 mag rmag [20/24] SDSS r band AB magnitude
33 A1 --- l_imag Limit flag on imag
34- 39 F6.2 mag imag [19.5/24.5] SDSS i band AB magnitude
41 A1 --- l_Ymag Limit flag on Ymag
42- 47 F6.2 mag Ymag [17.6/20.5] UKIDSS Y band magnitude
49 A1 --- l_Jmag Limit flag on Jmag
50- 55 F6.2 mag Jmag [16.5/19.6] UKIDSS J band magnitude
57 A1 --- l_Hmag Limit flag on Hmag
58- 63 F6.2 mag Hmag [15/19] UKIDSS H band magnitude
65- 69 F5.2 mag Kmag [13.5/17] UKIDSS K band magnitude
71 A1 --- l_J-K Limit flag on J-K
72- 76 F5.2 mag J-K [1.5/3.5] The (J-K) color index
78 A1 --- l_r-K Limit flag on r-K
79- 83 F5.2 mag r-K [5/8] The (r-K) color index
85- 90 F6.2 mJy S20 [1/863] FIRST 20cm (1.4GHz) flux density
92- 95 I04 --- NIR ? Near-IR spectroscopy reference (1)
97-102 A6 --- Opt Optical spectroscopy reference (2)
104-109 A6 --- Class Source classification: Galaxy, QSO or
NLAGN (narrow-lines AGN)
111-116 F6.3 --- z [0.2/2.6]?=-9.999 Redshift (spectroscopic,
unless "photz" specified in comment)
118-129 A12 --- Com Additional comment (3)
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Note (1): NIR reference as follows:
0808 = TripleSpec 2008 August;
0309 = TripleSpec 2009 March;
1109 = TripleSpec 2009 November;
0911 = TripleSpec 2011 September;
0413 = TripleSpec 2013 April.
Note (2): Optical spectra as follows:
SDSS = SDSS DR7 spectrum;
SDSS3 = SDSS DR9 spectrum;
AUS = redshift from AUS (AAOmega-UKIDSS-SDSS Survey; Croom et al., in prep);
LRIS = Keck LRIS 2012 October;
2SLAQ = 2dF-SDSS LRG and QSO survey (Cannon et al. 2006, J/MNRAS/372/425;
superseded by J/MNRAS/392/19).
Glik07 = F2M Quasar from Glikman et al. (2007, J/ApJ/667/673);
Glik12 = F2M Quasar from Glikman et al. (2012, J/ApJ/757/51).
Note (3): Abbreviations in Comment:
photz = Hsieh et al. (2005, J/ApJS/158/161) for 02:25:18.77 +00:34:16.9
photz = Hsieh et al. (2005, J/ApJS/158/161) for 02:25:34.32 +01:08:38.1
merger = Hwang & Chang (2009, J/ApJS/181/233) for 23:36:33.52 -00:49:57.3
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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 --- --- [UKFS]
6- 14 A9 --- UKFS UKFS designation (HHMM+DDMM; J2000)
16- 17 I2 h RAh Hour of right ascension (J2000)
19- 20 I2 min RAm Minute of right ascension (J2000)
22- 26 F5.2 s RAs Second of right ascension (J2000)
28 A1 --- DE- Sign of declination (J2000)
29- 30 I2 deg DEd Degree of declination (J2000)
32- 33 I2 arcmin DEm Arcminute of declination (J2000)
35- 38 F4.1 arcsec DEs Arcsecond of declination (J2000)
40- 44 F5.3 --- z [0.2/2.6] Redsfhit
46- 50 F5.2 mag Ksmag [13.5/17] Ks-band magnitude
52- 55 F4.2 mag E(B-V)p E(B-V) photometric
56 A1 --- f_E(B-V)p [a] Value based on 2-component quasar (1)
58- 61 F4.2 mag E(B-V)o [0.15/1.07]? Optical E(B-V)
63- 67 F5.2 mag E(B-V)i [-0.34/1.5]? Near-IR E(B-V)
69- 72 F4.2 mag E(B-V)c [0.3/0.89]? Combined E(B-V)
74- 79 F6.2 mag KMag0 [-32/-24] De-reddened absolute K-band magnitude
80 A1 --- f_KMag0 [a] Value based on 2-component quasar (1)
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Note (1): the "a" indicates values based on the two-component quasar plus
host galaxy fits described in Section 6.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 27-Apr-2015