J/ApJ/829/33 Luminous of high-z QSOs with SDSS and WISE. II (Yang+, 2016)
A Survey of Luminous High-redshift Quasars with SDSS and WISE. II. The Bright
End of the Quasar Luminosity Function at z ~= 5.
Yang J., Wang F., Wu X.-B., Fan X., McGreer I.D., Bian F., Yi W., Yang Q.,
Ai Y., Dong X., Zuo W., Green R., Jiang L., Wang S., Wang R., Yue M.
<Astrophys. J., 829, 33 (2016)>
=2016ApJ...829...33Y 2016ApJ...829...33Y
ADC_Keywords: QSOs ; Redshifts ; Photometry, SDSS ; Photometry, infrared ;
Spectroscopy
Keywords: galaxies: active - galaxies: high-redshift - quasars: general
Abstract:
This is the second paper in a series on a new luminous z∼5 quasar
survey using optical and near-infrared colors. Here we present a new
determination of the bright end of the quasar luminosity function
(QLF) at z∼5. Combining our 45 new quasars with previously known
quasars that satisfy our selections, we construct the largest uniform
luminous z∼5 quasar sample to date, with 99 quasars in the range
of 4.7≤z<5.4 and -29<M1450≤-26.8, within the Sloan Digital
Sky Survey (SDSS) footprint. We use a modified 1/Va method including
flux limit correction to derive a binned QLF, and we model the
parametric QLF using maximum likelihood estimation. With the faint-end
slope of the QLF fixed as α=-2.03 from previous deeper samples,
the best fit of our QLF gives a flatter bright end slope
β=-3.58±0.24 and a fainter break magnitude
M1450*=-26.98±0.23 than previous studies at similar
redshift. Combined with previous work at lower and higher redshifts,
our result is consistent with a luminosity evolution and density
evolution model. Using the best-fit QLF, the contribution of quasars
to the ionizing background at z∼5 is found to be 18%-45% with a
clumping factor C of 2-5. Our sample suggests an evolution of radio
loud fraction with optical luminosity but no obvious evolution with
redshift.
Description:
Our SDSS+WISE selection technique and spectroscopic follow-up
observations were discussed in detail in Wang et al. (2016, Cat.
J/ApJ/819/24). Our spectroscopic follow-up campaign started in 2013
October with the Lijiang 2.4m telescope (LJT) and Xinglong 2.16m
telescope in China, the Kitt Peak 2.3m Bok telescope and 6.5m MMT
telescope in the U.S., as well as the 2.3m ANU telescope in Australia.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . this file
table1.dat 102 99 z∼5 quasar sample used for QLF measurement
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See also:
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/294 : The SDSS Photometric Catalog, DR7 (Adelman-McCarthy+, 2009)
V/147 : The SDSS Photometric Catalog, DR12 (Alam+, 2015)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/A+A/585/A87 : Quasar composite made from bright QSOs (Selsing+, 2016)
J/ApJ/819/24 : z>4.5 QSOs with SDSS and WISE. I. Opt. spectra (Wang+, 2016)
J/ApJ/794/75 : HST-COS UV spectra observations of AGNs (Stevans+, 2014)
J/ApJ/768/105 : z∼5 QSO luminosity function from SDSS Stripe 82
(McGreer+, 2013)
J/ApJ/773/14 : BOSS: quasar luminosity function (Ross+, 2013)
J/ApJ/755/169 : 3<z<5 quasar luminosity function in COSMOS (Masters+, 2012)
J/ApJ/728/23 : GALEX UV-bright high-redshift quasars (Worseck+, 2011)
J/ApJ/710/1498 : QSO luminosity function at z∼4 (Glikman+, 2010)
J/AJ/131/2788 : Redshifts in the SFQS survey (Jiang+, 2006)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/MNRAS/341/993 : ujbr photometry and redshifts of QSOs (Cirasuolo+, 2003)
J/ApJ/445/62 : Radio properties of optically selected quasars (Hooper+ 1995)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- Name Source identifier (JHHMMSS.ss+DDMMSS.ss)
21 A1 --- f_Name Flag on Name (1)
23- 27 F5.2 mag rmag [19.48/22.35] SDSS r magnitude (2)
29- 32 F4.2 mag e_rmag [0.02/0.15] Error in rmag (2)
34- 38 F5.2 mag imag [17.96/20.15] SDSS i magnitude (2)
40- 43 F4.2 mag e_imag [0.01/0.07] Error in imag (2)
45- 49 F5.2 mag zmag [17.47/19.49] SDSS z magnitude (2)
51- 54 F4.2 mag e_zmag [0.02/0.1] Error in zmag (2)
56- 60 F5.2 mag W1mag [14.31/16.89] W1 magnitude (3)
62- 65 F4.2 mag e_W1mag [0.03/0.28] Error in W1mag (3)
67- 71 F5.2 mag W2mag [13.46/16.11] W1 magnitude (3)
73- 76 F4.2 mag e_W2mag [0.03/0.18] Error in W2mag (3)
78- 81 F4.2 --- Redshift [4.7/5.37] Redshift
83- 88 F6.2 mag M1450 [-28.99/-26.8] Absolute 1450Å AB magnitude
90-102 A13 --- Notes Quasar origin (4)
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Note (1): Flag on Name, defined as follows:
b = This quasar discovered by McGreer et al. (2009AJ....138.1925M 2009AJ....138.1925M) using the
radio-selection method was also observed by us and we use the new spectra
for the M1450 calculation.
c = This quasar discovered by Schneider et al. (1991AJ....102..837S 1991AJ....102..837S) was also
observed by us and we use the new spectra for the M1450 calculation.
Note (2): Photometric data from the SDSS are in the SDSS photometric system
(Lupton et al. 1999AJ....118.1406L 1999AJ....118.1406L), which is almost identical to
the AB system at bright magnitudes.
Note (3): Photometric data from ALLWISE are in the Vega system.
Note (4): The quasar origin is defined as follows:
DR7 = Quasars from the SDSS DR7
DR12 = Quasars from the SDSS DR12
PaperI = Quasars identified by Wang et al. 2016ApJ...819...24W 2016ApJ...819...24W,
Cat. J/ApJ/819/24
Schneider1991 = Schneider et al. 1991AJ....102..837S 1991AJ....102..837S
McGreer2009 = McGreer et al. 2009AJ....138.1925M 2009AJ....138.1925M
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History:
From electronic version of the journal
References:
Wang et al. Paper I 2016ApJ...819...24W 2016ApJ...819...24W, Cat. J/ApJ/819/24
(End) Marianne Brouty [CDS] 08-Mar-2018