J/ApJ/710/1498 QSO luminosity function at z∼4 (Glikman+, 2010)
The faint end of the quasar luminosity function at z ∼ 4.
Glikman E., Bogosavljevic M., Djorgovski S.G., Stern D., Dey A.,
Jannuzi B.T., Mahabal A.
<Astrophys. J., 710, 1498-1514 (2010)>
=2010ApJ...710.1498G 2010ApJ...710.1498G
ADC_Keywords: QSOs ; Redshifts ; Magnitudes ; Surveys
Keywords: cosmology: observations - large-scale structure of universe -
galaxies: luminosity function, mass function - quasars: general -
surveys
Abstract:
The evolution of the quasar luminosity function (QLF) is one of the
basic cosmological measures providing insight into structure formation
and mass assembly in the universe. We have conducted a spectroscopic
survey to find faint quasars (-26.0<M1450←22.0) at redshifts
z=3.8-5.2 in order to measure the faint end of the QLF at these early
times. Using available optical imaging data from portions of the NOAO
Deep Wide-Field Survey and the Deep Lens Survey, we have
color-selected quasar candidates in a total area of 3.76deg2. Thirty
candidates have R≤23mag. We conducted spectroscopic follow-up for 28
of our candidates and found 23 QSOs, 21 of which are reported here for
the first time, in the 3.74<z<5.06 redshift range.
Description:
We make use of publicly available deep imaging data from the NDWFS
(NOAO Deep Wide-Field Survey) in the Bootes field from the DR3
(BW,R,I bands) and from the DLS (Deep Lens Survey; DR3 in B,V,R and
z' bands). DLS is closely related to the NDWFS in that the optical
imaging has been obtained on the same 4m Mayall Telescope (at KPNO)
and Blanco Telescope (at CTIO) using the same wide-field optical
imagers Mosaic-I and Mosaic-II as the NDWFS.
We obtained 28 spectra for the DLS and NDWFS candidates and found 23
high-redshift quasars (the remaining objects were three Lyman-break
galaxies (LBGs) at z∼3.9, one Type-II active galactic nucleus (AGN) at
z∼0.2 and one featureless, unidentified spectrum). All but two of our
spectra were taken with the Low-Resolution Imaging Spectrometer (LRIS)
on the Keck I telescope on Mauna Kea. Five quasars were discovered on
UT 2005 November 28 and 29. Only the red camera was used, with the
400lines/mm grating blazed at 8500Å. Sixteen additional quasars
were discovered during a run on UT 2006 May 20-22. Two additional
spectra were taken on UT 2006 March 25 and 26 with the Multi-Aperture
Red Spectrometer (MARS) on the Mayall 4m telescope at Kitt Peak.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 82 77 NOAO Deep Wide-Field Survey (NDWFS) candidates
table4.dat 89 70 Deep Lens Survey (DLS) candidates
table5.dat 95 23 z≳4 quasar sample
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See also:
J/A+A/535/A38 : Observations of NOAO Bootes field at 153MHz (Intema+, 2011)
J/ApJ/699/782 : High-redshift SDSS-DR5 QSOs (Diamond-Stanic+, 2009)
J/ApJ/693/8 : High-redshift QSOs in the COSMOS survey (Brusa+, 2009)
J/ApJ/675/49 : High-redshift QSOs in the SWIRE survey (Siana+, 2008)
J/AJ/133/2222 : Clustering of high-redshift QSOs from SDSS (Shen+, 2007)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/ApJ/641/140 : Optical counterparts in the NDWFS Bootes field (Brand+, 2006)
J/ApJS/161/9 : X-ray survey of the NDWFS Bootes field (Kenter+, 2005)
J/AJ/121/31 : High-redshift quasars in SDSS (Fan+, 2001)
http://www.archive.noao.edu/ndwfs/ : NOAO Deep Wide-Field Survey home page
http://dls.physics.ucdavis.edu/ : Deep Lens Survey home page
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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- 33 A9 --- Field Field identification (1)
35- 39 F5.2 mag BWmag The BW band magnitude (AB mag) (G1)
41- 45 F5.2 mag e_BWmag ?=99 Uncertainty in BWmag (2)
47- 51 F5.2 mag Rmag The R band magnitude (AB mag) (G1)
53- 56 F4.2 mag e_Rmag Uncertainty in Rmag
58- 62 F5.2 mag Imag The I band magnitude (AB mag) (G1)
64- 67 F4.2 mag e_Imag Uncertainty in Imag
69- 72 F4.2 arcsec FWHM Full-Width at Half-Maximum in R band
74- 77 F4.2 --- z ? Redshift
79- 82 A4 --- Class Source classification (AGN, LBG (Lyman-break
galaxie), QSO, ? or null)
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Note (1): Fields (described in table 1):
---------------------------------------------------------------------------
Field id Field RA+DEC (J2000) Size (') FWHMR EXPR
---------------------------------------------------------------------------
1426p3236 NDWFS J1426+3236 14:26:03.74+32:36:31.72 36.8x38.0 0.94 6000
1431p3236 NDWFS J1431+3236 14:31:36.14+32:36:46.29 36.8x38.0 0.91 6000
1434p3421 NDWFS J1434+3421 14:34:30.79+34:21:54.18 35.8x37.4 0.98 4200
1437p3347 NDWFS J1437+3347 14:37:16.32+33:47:01.72 36.9x38.0 0.87 6000
1437p3457 NDWFS J1437+3457 14:37:24.59+34:57:02.13 35.5x38.0 1.07 10800
---------------------------------------------------------------------------
Note (2):
99.0 = BWmag is an upper limit.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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- 29 A5 --- Field Field identification (1)
31- 35 F5.2 mag Bmag The B band magnitude (AB mag)(G1)
37- 41 F5.2 mag e_Bmag ?=99 Uncertainty in Bmag (2)
43- 47 F5.2 mag Vmag The V band magnitude (AB mag) (G1)
49- 52 F4.2 mag e_Vmag Uncertainty in Rmag
54- 58 F5.2 mag Rmag The R band magnitude (AB mag) (G1)
60- 63 F4.2 mag e_Rmag Uncertainty in Rmag
65- 69 F5.2 mag zmag The z band magnitude (AB mag) (G1)
71- 74 F4.2 mag e_zmag Uncertainty in zmag
76- 79 F4.2 arcsec FWHM Full-Width at Half-Maximum in R band
81- 85 F5.2 --- z ? Redshift
87- 89 A3 --- Class Source classification (QSO or null)
--------------------------------------------------------------------------------
Note (1): Fields (described in table 2):
-------------------------------------------------------
Field RA (J2000) DE Size (') FWHMR EXPR
-------------------------------------------------------
F2p21 09:22:37.1+30:00:00 35.1x35.1 0.86 18000
F2p31 09:22:37.1+29:20:00 35.1x35.1 0.78 18000
F2p33 09:16:27.7+29:20:00 35.1x35.1 0.86 18000
F4p23 10:49:19.4-05:00:00 35.1x35.1 0.89 18000
F4p31 10:54:40.8-05:40:00 35.1x35.1 0.87 18000
F4p32 10:52:00.0-05:40:00 35.1x35.1 0.89 18000
-------------------------------------------------------
Note (2):
99.0 = Bmag is an upper limit.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Set NDWFS (table 3) or DLS (table4) survey
7- 26 A20 --- Name NDWFS or DLS name (JHHMMSS.ss+DDMMSS.s)
27- 31 F5.2 mag Rmag The R band magnitude (AB mag) (G1)
33- 36 F4.2 --- z Redshift (spectroscopic)
38- 42 F5.3 --- Fsel The selection function (fsel)
44- 48 F5.3 --- Fspec [0/1] Spectroscopic completeness (fspec)
50- 55 F6.2 mag M1450s Absolute magnitude at rest-frame 1450Å
from simulations (1)
57- 60 F4.2 --- zlims Limiting redshift from simulations (1)(2)
61 A1 --- Rem [bc] survey magnitude limit > 23 (2)
63- 68 F6.1 Mpc3/arcmin2 Vas Available volume from simulations (1)(2) (4)
69 A1 --- --- [bc] survey magnitude limit > 23 (2)
71- 76 F6.2 mag M1450 M1450 from spectrum
78- 81 F4.2 --- zlim Limiting redshift from spectrum (2)
82 A1 --- --- [bc] survey magnitude limit > 23 (2)
84- 89 F6.1 Mpc3/arcmin2 Vasp Available volume from spectrum (2)(4)
90 A1 --- --- [bc] survey magnitude limit > 23 (2)
92- 95 F4.2 deg2 Area Area
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Note (1): To define color selection criteria for quasar candidates at z≳4
and determine our selection function, we simulated quasar spectra
following the general procedure outlined in Fan (1999AJ....117.2528F 1999AJ....117.2528F)
and Richards et al. (2006, Cat. J/AJ/131/2766) and calculated their
colors for the NDWFS and DLS filter combinations. We generated a
library of simulated quasar spectra, starting with a quasar template
spectrum constructed from a combination of the Hubble Space Telescope
(HST) radio-quiet quasar composite spectrum from Telfer et al.
(2002ApJ...565..773T 2002ApJ...565..773T) which covers 300-2461Å in the quasar rest
frame and the SDSS quasar composite spectrum (Vanden Berk et al.
2001AJ....122..549V 2001AJ....122..549V) spanning rest-frame 800-9200Å. See section 3
for further details.
Note (2): These values are computed to a survey magnitude limit of R=23,
unless flagged with:
b = values were computed to a survey magnitude limit of R=23.5.
c = values were computed to a survey magnitude limit of R=24.
Note (4): The available volume, Va, is the comoving volume within which
a quasar with redshift z and magnitude R can be found.
See section 5.3 for further details.
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Global notes:
Note (G1): All magnitudes have been corrected for interstellar extinction
using the dust map from Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S). For
our selection, we work with these extinction and aperture-corrected
magnitudes in the ABv system, converting the published Vega-based
NDWFS zero points to ABv magnitudes by adding 0.0, 0.26, and 0.53mag
to the BW, R, and I zero points, respectively. For the DLS, we
convert from Vega magnitudes to ABv by adding -0.09, 0.0, and 0.26
to the B, V, and R zero points, respectively. See section 2 for
further details.
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Nomenclature Notes:
In table 3, sources are in Simbad.
In table 4, sources are in Simbad.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 26-Mar-2012