J/ApJ/743/125 Likelihood method for QSOs selection (Kirkpatrick+, 2011)
A simple likelihood method for quasar target selection.
Kirkpatrick J.A., Schlegel D.J., Ross N.P., Myers A.D., Hennawi J.F.,
Sheldon E.S., Schneider D.P., Weaver B.A.
<Astrophys. J., 743, 125 (2011)>
=2011ApJ...743..125K 2011ApJ...743..125K
ADC_Keywords: Photometry, SDSS ; Redshifts ; QSOs ; Surveys ; Models
Keywords: cosmology: observations - galaxies: distances and redshifts -
large-scale structure of universe - methods: statistical -
quasars: general - stars: general - stars: statistics - surveys
Abstract:
We present a new method for quasar target selection using photometric
fluxes and a Bayesian probabilistic approach. For our purposes, we
target quasars using Sloan Digital Sky Survey (SDSS) photometry to a
magnitude limit of g=22. The efficiency and completeness of this
technique are measured using the Baryon Oscillation Spectroscopic
Survey (BOSS) data taken in 2010. This technique was used for the
uniformly selected (CORE) sample of targets in BOSS year-one
spectroscopy to be realized in the ninth SDSS data release. When
targeting at a density of 40 objects deg-2 (the BOSS quasar
targeting density), the efficiency of this technique in recovering
z>2.2 quasars is 40%. The completeness compared to all quasars
identified in BOSS data is 65%. This paper also describes possible
extensions and improvements for this technique.
Description:
The SDSS-III: Baryon Oscillation Spectroscopic Survey (BOSS;
Eisenstein et al. 2011AJ....142...72E 2011AJ....142...72E) is specifically targeting z>2.2
quasi-stellar objects (QSOs) in order to observe 150000 Lyα
forest (LyαF) lines of sight. In this paper, we describe a new
method for quasar target selection. Our method models data in
five-filter flux space, then calculates likelihood estimates that a
given object is a z>2.2 quasar. Our likelihood method was used for the
uniformly selected sample (which we refer to hereafter as "CORE")
in the first year of the BOSS QSO target selection (Ross et al.
2012, Cat. J/ApJS/199/3).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 24 2050 McDonald (2009, priv. com.) weights
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See also:
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
VII/269 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)
J/AJ/142/78 : New 2.2<z<3 quasars from SDSS and UKIDSS (Wu+, 2011)
J/ApJ/728/26 : QSO selection based on photometry (MacLeod+, 2011)
J/ApJ/719/1672 : SDSS binary quasars at high redshift. I. (Hennawi+, 2010)
J/ApJ/699/782 : High-redshift SDSS-DR5 QSOs (Diamond-Stanic+, 2009)
J/AJ/137/3884 : Quasar candidates selected from the SDSS (Richards+, 2009)
J/ApJS/180/67 : Photometric selection of QSOs from SDSS. II. (Richards+, 2009)
J/MNRAS/392/19 : The 2dF-SDSS QSO survey (Croom+, 2009)
J/ApJ/654/115 : DEEP2 Galaxy Redshift Survey: SDSS QSOs (Coil+, 2007)
J/AJ/131/2788 : Redshifts in the SFQS survey (Jiang+, 2006)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/ApJS/155/257 : NBC Quasar Candidate Catalog (Richards+, 2004)
J/AJ/126/2579 : SDSS quasar catalog. II. First data release (Schneider+, 2003)
J/AJ/121/31 : High-redshift quasars in SDSS (Fan+, 2001)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 F4.2 --- z [2/4] Redshift
6- 12 F7.4 mag rmag [17.5/23.5] SDSS r-band magnitude
14- 24 E11.5 --- Weight [0/1] Corresponding weight wO' in the
likelihood function (see section 4.3)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 07-May-2013