J/ApJ/658/99 Pairs of QSO in SDSS-DR4 (Myers+, 2007)
Clustering analyses of 300,000 photometrically classified quasars.
II. The excess on very small scales.
Myers A.D., Brunner R.J., Richards G.T., Nichol R.C., Schneider D.P.,
Bahcall N.A.
<Astrophys. J., 658, 99-106 (2007)>
=2007ApJ...658...99M 2007ApJ...658...99M
ADC_Keywords: Surveys ; QSOs ; Redshifts ; Photometry, SDSS
Keywords: cosmology: observations - large-scale structure of universe -
quasars: general - surveys
Abstract:
We study quasar clustering on small scales, modeling clustering
amplitudes using halo-driven dark matter descriptions. From 91 pairs
n scales <35h-1kpc, we detect only a slight excess in quasar
clustering over our best-fit large-scale model. Integrated across all
redshifts, the implied quasar bias is bQ=4.21±0.98 (bQ=3.93±0.71)
at ∼18h-1kpc (∼28h-1kpc).
Description:
The "KDE" data sample used in this paper, which is constructed using
the kernel density estimation (KDE) technique of Richards et al.
(2004, Cat. J/ApJS/155/257), is detailed in Paper I, Myers et al.
(2006ApJ...638..622M 2006ApJ...638..622M).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 196 111 Quasar pairs in the DR4 KDE catalog with
separations <0.1'
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See also:
II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007)
J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006)
J/A+A/459/L1 : Supercluster sample from SDSS DR4 (Einasto+, 2006)
J/A+A/471/17 : SDSS-DR4 nearby clusters global properties (Aguerri+, 2007)
http://www.sdss.org/dr4/ : SDSS-DR4 Home Page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
5- 23 A19 --- SDSS1 First component of Quasar pair name,
JHHMMSS.ss+DDMMSS.s
25- 26 I2 h RAh Pair1 Hour of Right Ascension (J2000)
28- 29 I2 min RAm Pair1 Minute of Right Ascension (J2000)
31- 35 F5.2 s RAs Pair1 Second of Right Ascension (J2000)
37 A1 --- DE- Pair1 Sign of the Declination (J2000)
38- 39 I2 deg DEh Pair1 Degree of Declination (J2000)
41- 42 I2 arcmin DEm Pair1 Arcminute of Declination (J2000)
44- 47 F4.1 arcsec DEs Pair1 Arcsecond of Declination (J2000)
49- 53 F5.2 --- umag1 Pair1 SDSS u band magnitude (1)
55- 59 F5.2 --- gmag1 Pair1 SDSS g band magnitude (1)
61- 64 F4.2 --- zph1l Pair1 photometric redshift range minimum
66- 70 F5.3 --- zph1m Pair1 photometric redshift range midpoint
72- 75 F4.2 --- zph1u Pair1 photometric redshift range maximum
77- 81 F5.3 --- zsp1 ? Pair1 spectroscopic redshift
83- 88 A6 --- f_zsp1 Flag on zspec1 (2)
89- 93 F5.3 --- zsp1b ? Second Pair1 spectroscopic redshift
94 A1 --- r_zsp1b [b] Reference for zspecb (3)
96- 99 A4 --- --- [SDSS]
100-118 A19 --- SDSS2 Second component of Quasar pair name,
JHHMMSS.ss+DDMMSS.s
120-121 I2 h RA2h Pair2 Hour of Right Ascension (J2000)
123-124 I2 min RA2m Pair2 Minute of Right Ascension (J2000)
126-130 F5.2 s RA2s Pair2 Second of Right Ascension (J2000)
132 A1 --- DE2- Pair2 Sign of the Declination (J2000)
133-134 I2 deg DE2h Pair2 Degree of Declination (J2000)
136-137 I2 arcmin DE2m Pair2 Arcminute of Declination (J2000)
139-142 F4.1 arcsec DE2s Pair2 Arcsecond of Declination (J2000)
144-148 F5.2 --- umag2 Pair2 SDSS u band magnitude (1)
150-154 F5.2 --- gmag2 Pair2 SDSS g band magnitude (1)
156-159 F4.2 --- zph2l Pair2 photometric redshift range minimum
161-165 F5.3 --- zph2m Pair2 photometric redshift range midpoint
167-170 F4.2 --- zph2u Pair2 photometric redshift range maximum
172-176 F5.3 --- zsp2 ? Pair2 spectroscopic redshift
178-183 A6 --- n_zsp2 Note about Pair2 (2)
184-188 F5.3 --- zsp2b ? Pair2 alternative spectroscopic redshift
190 A1 --- r_zsp2b [b] Reference for zspec2b (3)
192-195 F4.2 arcsec Delta Angular separation of Quasar pair
196 A1 --- f_Delta [*] Objects in high absorption regions (Ag>21)
have a higher probability of being stars.
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Note (1): Photometry is "as observed" (not been corrected for Galactic
extinction).
Note (2): The reference follows spectroscopic redshift with the
following code:
a = Source: DR4 Catalog Archive Server (e.g., likely Schneider
et al., 2005AJ....130..367S 2005AJ....130..367S, Cat. VII/243)
b = Source: Hennawi et al. (2006, Cat. J/AJ/131/1)
c = Source: Sramek & Weedman (1978ApJ...221..468S 1978ApJ...221..468S),
Djorgovski & Spinrad (1984, in in ASP Conf. Ser. 21, 349)
d = Probable binary quasar-starburst (Brotherton et al.,
1999ApJ...520L..87B 1999ApJ...520L..87B)
* = Objects in Galactic regions with absorption Ag>0.21. These
were not included in our main analysis, as it is known (see,
the Appendixes of Paper I, Myers et al. (2006ApJ...638..622M 2006ApJ...638..622M))
that such objects have a higher probability of being stars
? = Object with low confidence redshift
?? = High probability lens (as recorded at
http://cfa-www.harvard.edu/castles/ )
Note (3): b = the alternative redshift from Hennawi et al. (2006, Cat.
J/AJ/131/1) is provided where there is a redshift available from
this reference in addition to that available in the DR4 CAS.
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History:
From electronic version of the journal
References:
Myers et al., Paper I 2006ApJ...638..622M 2006ApJ...638..622M
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 09-Jan-2009