J/ApJ/863/144 The ELQS in SDSS footprint. II. North Gal. Cap (Schindler+, 2018)
The Extremely Luminous Quasar Survey in the Sloan Digital Sky Survey footprint.
II. The North Galactic Cap sample.
Schindler J.-T., Fan X., McGreer I.D., Yang J., Wang F., Green R.,
Garavito-Camargo N., Huang Y.-H., O'Donnell C., Patej A., Pucha R.,
Rees J.M., Spalding E.
<Astrophys. J., 863, 144 (2018)>
=2018ApJ...863..144S 2018ApJ...863..144S
ADC_Keywords: QSOs; Surveys; Photometry, SDSS; Photometry, ultraviolet;
Redshifts; Photometry, infrared; Radio sources
Keywords: galaxies: active ; galaxies: high-redshift ; galaxies: nuclei ;
quasars: general
Abstract:
We present the North Galactic Cap sample of the Extremely Luminous
Quasar Survey (ELQS-N), which targets quasars with M1450<-27 at
2.8≤z<5 in an area of ∼7600deg2 of the Sloan Digital Sky Survey
(SDSS) footprint with 90°<RA<270°. Based on a
near-infrared/infrared JKW2 color cut, the ELQS selection efficiently
uses random forest methods to classify quasars and to estimate
photometric redshifts; this scheme overcomes some of the difficulties
of pure optical quasar selection at z∼3. As a result, we retain a
completeness of >70% over z∼3.0-5.0 at mi≲17.5, limited toward
fainter magnitudes by the depth of the Two Micron All Sky Survey. The
presented quasar catalog consists of a total of 270 objects, of which
39 are newly identified in this work with spectroscopy obtained at the
Vatican Advanced Technology Telescope and the MMT 6.5m telescope. In
addition to the high completeness, which allowed us to discover new
quasars in the already well-surveyed SDSS North Galactic Cap, the
efficiency of our selection is relatively high at ∼79%. Using 120
objects of this quasar sample we are able to extend the previously
measured optical quasar luminosity function (QLF) by one magnitude
toward the bright end at 2.8≤z≤4.5. A first analysis of the QLF
suggests a relatively steep bright-end slope of β~-4 for this
sample. This result contrasts with previous results in the same
redshift range, which find a much flatter slope around β~-2.5,
but agrees with recent measurements of the bright-end slope at lower
and higher redshifts. Our results constrain the bright-end slope at
z=2.8-4.5 to β<-2.94 with a 99% confidence.
Description:
The 88 North Galactic Cap sample of the Extremely Luminous Quasar
Survey (ELQS-N) primary candidates were observed with the Vatican
Advanced Technology Telescope (VATT) and the MMT 6.5m Telescope.
The spectra have a resolution of R∼1000 and a coverage of ∼4000Å
around a central wavelength of ∼5775Å.
The observations for the ELQS were conducted in multiple campaigns.
Pilot observations started in 2015 April 21-25, with continuing
observations in October 8-12. The program continued through 2016 March
10-15, April 10-13, November 19-23, and December 18-20. In 2017 we
finished the North Galactic Cap footprint with observations on April
3-6, April 17-19, and May 3-5.
We have used the MMT Red Channel Spectrograph to carry out followup
observations of our newly discovered quasars.
Observations were taken in 2015 on May 9, November 8-9 and 11, and
December 1 as well as in 2017 on May 17-18; with R∼300-400.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 87 39 Newly discovered quasars at z≥2.8 in
the ELQS-N sample
table6.dat 608 270 The North Galactic Cap sample of the Extremely
Luminous Quasar Survey (ELQS-N) catalog
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
II/328 : AllWISE Data Release (Cutri+ 2013)
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
II/335 : Revised cat. of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)
VII/283 : The Million Quasars (Milliquas) catalog (6.3) (Flesch, 2019)
J/ApJS/95/1 : Atlas of Quasar Energy Distributions (Elvis+ 1994)
J/ApJ/635/123 : The SDSS-DR3 damped Lyα survey (Prochaska+, 2005)
J/ApJ/640/579 : Near-infrared spectra of 27 SDSS quasars (Glikman+, 2006)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/ApJS/165/1 : BAL QSOs from SDSS DR3 (Trump+, 2006)
J/MNRAS/383/1513 : 2MASS, SDSS and FIRST fluxes of QSOs (Labita+, 2008)
J/MNRAS/386/1605 : Luminous K-band selected QSOs from UKIDSS (Maddox+, 2008)
J/ApJS/180/67 : Phot. selection of quasars from SDSS. II. (Richards+, 2009)
J/MNRAS/406/1583 : Quasar from SDSS and UKIDSS (Wu+, 2010)
J/MNRAS/410/860 : Redshift dependence of BAL QSOs (Allen+, 2011)
J/ApJ/728/23 : GALEX UV-bright high-redshift quasars (Worseck+, 2011)
J/AJ/143/119 : SDSS Quasar Lens Search. V. Final catalog (Inada+, 2012)
J/ApJ/755/169 : 3<z<5 QSO luminosity function in the COSMOS (Masters+, 2012)
J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)
J/ApJ/746/169 : Luminosity function of broad-line quasars (Shen+, 2012)
J/AJ/144/49 : Quasars from SDSS-DR7, WISE and UKIDSS surveys (Wu+, 2012)
J/ApJ/768/105 : z∼5 QSO LF from SDSS Stripe 82 (McGreer+, 2013)
J/ApJ/773/14 : BOSS: quasar luminosity function (Ross+, 2013)
J/ApJ/778/127 : UKIDSS+FIRST+SDSS red QSOs candidates (Glikman+, 2013)
J/ApJS/219/39 : QSOs selection from SDSS and WISE (Richards+, 2015)
J/ApJS/221/12 : AGNs in the MIR using AllWISE data (Secrest+, 2015)
J/ApJS/227/11 : PS1 z>5.6 quasars follow-up (Banados+, 2016)
J/A+A/588/A103 : 2nd ROSAT all-sky survey (2RXS) source cat. (Boller+, 2016)
J/A+A/585/A87 : Quasar composite made from bright QSOs (Selsing+, 2016)
J/ApJ/829/33 : Luminous of high-z QSOs with SDSS and WISE. II (Yang+, 2016)
J/MNRAS/473/4937 : AllWISE ctp to ROSAT/2RXS & XMMSLEW2 cat. (Salvato+, 2018)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh [8/17] Hour of Right Ascension (J2000)
4- 5 I2 min RAm Minute of Right Ascension (J2000)
7- 12 F6.3 s RAs Second of Right Ascension (J2000)
14- 14 A1 --- DE- Sign of the Declination (J2000)
15- 16 I2 deg DEd Degree of Declination (J2000)
18- 19 I2 arcmin DEm Arcminute of Declination (J2000)
21- 25 F5.2 arcsec DEs Arcsecond of Declination (J2000)
27- 31 F5.2 mag imag [17/18] SDSS DR13 i-band magnitude,
dereddened AB mag
33- 36 F4.2 mag e_imag [0.01/0.06] Uncertainty in imag
38- 43 F6.2 mag M1450 [-29/-27] Absolute magnitude
at rest-frame 1450Å
45- 49 F5.3 --- zspec [2.8/4.5] Spectroscopic redshift
51- 55 F5.2 mag NUVmag [20.4/22.8]? GALEX GR6/7 Near-UV magnitude
57- 60 F4.2 mag e_NUVmag [0.05/0.5]? Uncertainty in NUVmag
62- 66 F5.2 mag FUVmag [21.4/22.1]? GALEX GR6/7 Near-UV magnitude
68- 71 F4.2 mag e_FUVmag [0.3/0.6]? Uncertainty in FUVmag
73- 74 I2 --- BAL [-1/1]? Broad absorption line flag (G1)
76- 85 A10 "Y/M/D" Date Observation UT date
87 A1 --- Flag Flag (1)
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Note (1): Flag as follows:
d = These objects were also independently discovered by Yang+ (in prep.);
e = See also HST GO Proposal 13013 (PI: Gabor Worseck) and
Zheng+ (2015ApJ...806..142Z 2015ApJ...806..142Z).
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- WISEA AllWISE name (JHHMMSS.ss+DDMMSS.s;
as in II/328)
21- 33 F13.9 deg RASdeg SDSS DR13 Right Ascension (J2000)
35- 50 F16.12 deg DESdeg SDSS DR13 Declination (J2000)
52- 53 I2 h RAh Hour of SDSS DR13 Right Ascension (J2000)
55- 56 I2 min RAm Minute of Right Ascension (J2000)
58- 63 F6.3 s RAs Second of Right Ascension (J2000)
65- 65 A1 --- DE- Sign of SDSS DR13 Declination (J2000)
66- 67 I2 deg DEd Degree of SDSS DR13 Declination (J2000)
69- 70 I2 arcmin DEm Arcminute of Declination (J2000)
72- 76 F5.2 arcsec DEs Arcsecond of Declination (J2000)
78- 88 F11.7 deg RAWdeg WISE Right Ascension (J2000)
90-100 F11.7 deg DEWdeg WISE Declination (J2000)
102-110 A9 --- r_zbest Reference to QSO classification (1)
112-120 F9.7 --- zbest [2.8/4.7] Best redshift of the
quasar according to the reference
122-135 F14.10 mag M1450 [-31/-27] Absolute magnitude, 1450Å,
calculated using the k-correction
determined in this work
137-151 F15.13 --- Prob [0/1] Selection probability according to
our completeness calculation
153-163 F11.8 mag umag [17.7/26.4] SDSS DR13 u-band magnitude,
dereddened AB mag (2)
165-175 F11.8 mag gmag [16.4/20.4] SDSS DR13 g-band magnitude,
dereddened AB mag (2)
177-188 F12.9 mag rmag [15.3/19] SDSS DR13 r-band magnitude,
dereddened AB mag (2)
190-200 F11.8 mag imag [14.8/18] SDSS DR13 i-band magnitude,
dereddened AB mag (2)
202-213 F12.9 mag zmag [14.5/18.1] SDSS DR13 z-band magnitude,
dereddened AB mag (2)
215-227 F13.10 mag Jmag [14.2/18.1] 2MASS J-band,
dereddened AB mag
229-241 F13.10 mag Hmag [14/18.4] 2MASS H-band, dereddened AB mag
243-255 F13.10 mag Kmag [13.8/18.1] 2MASS Ks-band,
dereddened AB mag
257-269 F13.10 mag W1mag [13.7/18.2] ALLWISE W1 band,
dereddened AB mag
271-283 F13.10 mag W2mag [13.8/18.1] ALLWISE W2 band,
dereddened AB mag
285-294 F10.8 mag e_umag [0.01/3.7] Uncertainty in umag (2)
296-305 F10.8 mag e_gmag [0.01/0.3] Uncertainty in gmag (2)
307-317 F11.9 mag e_rmag [0.009/0.1] Uncertainty in rmag (2)
319-329 F11.9 mag e_imag [0.009/0.2] Uncertainty in imag (2)
331-340 F10.8 mag e_zmag [0.01/0.2] Uncertainty in zmag (2)
342-346 F5.3 mag e_Jmag [0.02/0.3]? Uncertainty in Jmag
348-352 F5.3 mag e_Hmag [0.02/0.4]? Uncertainty in Hmag
354-358 F5.3 mag e_Kmag [0.02/0.4]? Uncertainty in Kmag
360-364 F5.3 mag e_W1mag [0.02/0.2] Uncertainty in W1mag
366-370 F5.3 mag e_W2mag [0.02/0.2] Uncertainty in W2mag
372-387 F16.14 mag E(B-V) [0.006/0.4]? E(B-V) color excess
389-398 F10.8 mag Ai [0.006/0.6] Extinction in the SDSS i-band
400-404 A5 --- FIRST Boolean to indicate successful matches
with the FIRST catalog
406-422 F17.15 arcsec SepFIRST [1.6e-5/0.0006]? Distance of the FIRST
match relative to the SDSS position
424-430 F7.2 mJy/beam FpkFIRST [1/2405]? FIRST peak flux
432-438 F7.2 mJy FintFIRST [0.8/2431]? FIRST integrated flux
440-444 F5.3 mJy/beam e_FpkFIRST [0.1/0.6]? RMS error on the FIRST flux
446-450 A5 --- GALEX Boolean to indicate successful matches
with the GALEX GR6/7 catalog
452-465 F14.12 arcsec SepGALEX [0.1/1.7]? Distance of the GALEX GR6/7
match relative to the SDSS position
467-481 F15.10 mag NUVmag [19.6/23.8]? GALEX GR6/7 Near-UV flux
483-500 F18.13 mag e_NUVmag [0.01/0.7]? Uncertainty in NUVmag
502-516 F15.10 mag FUVmag [20.5/23]? GALEX GR6/7 Far-UV flux
518-535 F18.13 mag e_FUVmag [0.03/0.6]? Uncertainty in FUVmag
537-541 A5 --- TRXS Boolean to indicate successful matches to
the ROSAT 2RXS AllWISE counterparts
543-559 E17.11 arcsec SepTRXS [0/2.8e-14]? Match distance between the
ELQS AllWISE position to the ROSAT 2RXS
AllWISE position (3)
561-563 F3.1 --- f_TRXS ? Match Flag for ROSAT 2RXS AllWISE (4)
565-581 E17.11 mW/m2 FTRXS [1.7e-13/5.5e-13]? 2RXS flux, erg/s/cm2
583-599 E17.11 mW/m2 e_FTRXS [6.5e-14/2.2e-13]? Uncertainty in FTRXS
601-602 I2 --- BAL [-1/1]? Broad absorption line flag (G1)
604-608 A5 --- QLF Included in the estimation of the quasar
luminosity function? (5)
--------------------------------------------------------------------------------
Note (1): Reference as follows:
DR14Q = SDSS-DR14 quasar catalog (Paris+, 2018A&A...613A..51P 2018A&A...613A..51P
See VII/279 --204 occurrences)
DR7Q = SDSS-DR7 quasar catalog (Schneider+, 2010, VII/260 --1 occurrence)
ELQS = the Extremely Luminous Quasar Survey (39 occurrences
--See Table 2)
MQ = Million Quasar Catalog (Flesch 2015, VII/273 superseded by VII/283
--15 occurrences)
SDSS_DR13 = SDSS-DR13 (Albareti+, 2017ApJS..233...25A 2017ApJS..233...25A --1 occurrence)
Yang = an ongoing survey by J. Yang et al. (2018, in preparation
--10 occurrences)
Note (2): All SDSS magnitudes are PSF magnitudes in the SDSS Asinh magnitude
system.
Note (3): Match distance between the ELQS AllWISE position to the ROSAT 2RXS
AllWISE position. The distance values are often 0 or otherwise extremely
small, because the positions match to numerical accuracy.
Note (4): A flag indicating the most probable AllWISE ROSAT 2RXS cross-match
with 1. This is the case for all matched objects.
Note (5): Boolean to indicate whether the quasar is included in the
estimation of the quasar luminosity function (Section 6).
--------------------------------------------------------------------------------
Global notes:
Note (G1): Visual qualitative broad absorption line (BAL) identification flag
as follows:
1 = BAL;
0 = no BAL;
-1 = insufficient wavelength coverage or inconclusive archival data.
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History:
From electronic version of the journal
References:
Schindler et al. Paper I. 2017ApJ...851...13S 2017ApJ...851...13S
Schindler et al. Paper II. 2018ApJ...863..144S 2018ApJ...863..144S This catalog
Schindler et al. Paper III. 2019ApJ...871..258S 2019ApJ...871..258S
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Aug-2019