J/A+A/564/A117 Binary quasars from LQAC-2 (Gattano+, 2014)
A whole sky study of quasars known population starting from the LQAC-2
compiled catalogue.
Gattano C., Souchay J., Barache C.
<Astron. Astrophys., 564, A117-117 (2014)>
=2014A&A...564A.117G 2014A&A...564A.117G
ADC_Keywords: QSOs ; Redshifts ; Photometry
Keywords: quasars: general - catalogs - astrometry
Abstract:
Thanks to huge surveys, such as the Sloan Digital Sky Survey (SDSS),
the last decade has shown a dramatic increase in the number of known
quasars. In the second release of the general compiled catalogue Large
Quasar Astrometric Catalogue (LQAC), 187504 objects are recorded.
From this catalogue, we carry out statistical studies dealing with
several topics: the astrometric accuracy of the quasars, their spatial
location, the distribution of the distance to the closest neighbour,
the identification of binary quasars, the completness of catalogues at
a given magnitude and the estimation of the number of quasars expected
to be detected by the astrometric space mission Gaia.
We analyse the astrometric improvements brought by the LQAC-2 in terms
of equatorial coordinates off-sets. We plot the bi-dimensional spatial
distribution of the LQAC-2 quasars according to their equatorial,
galactic, and ecliptic coordinates, thus exploring the anisotropy of
the distribution. We compare the observed distribution of closest
neighbours with the theoretical values based on a Poisson
distribution. Moreover, we perform a comparison between two
catalogues, the SDSS and the 2dF inside a huge common field. By
extrapolating to the whole sky we deduce the number of quasars that
will be detected by Gaia.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tab3-6.dat 81 36 Binary quasars (tables 3-6)
table7.dat 112 160 Binary quasars with the shortest separation,
between 0" and 30"
--------------------------------------------------------------------------------
See also:
VII/158 : Revised and Updated Catalog of QSO (Hewitt+ 1993)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
J/A+A/494/799 : Large Quasar Astrometric Catalogue (LQAC) (Souchay+, 2009)
J/A+A/537/A99 : Large Quasar Astrometric Catalogue 2 (LQAC-2) (Souchay+, 2012)
Byte-by-byte Description of file: tab3-6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- T [3/6] Table number (1)
3- 7 A5 --- --- [Lqac_]
8- 22 A15 --- QSO1/2 Quasar names (NNN+NNN_NNN/NNN)
24- 28 F5.3 --- z1 Redshift of first quasar
30- 34 F5.3 --- z2 Redshift of second quasar
36- 41 F6.3 arcsec theta [2/22] Separation angle
43- 46 F4.1 mag U1mag ?=- U magnitude of first quasar
48- 51 F4.1 mag U2mag ?=- U magnitude of first quasar
53- 55 A3 --- Ref Reference (2)
57 A1 --- Mult [*+] Indicates the other quasar for the triplet
59- 69 A11 --- QSO1 First QSO name (NNN+NNN_NNN)
70 A1 --- --- [/]
71- 81 A11 --- QSO2 Second QSO name (NNN+NNN_NNN)
--------------------------------------------------------------------------------
Note (2): LQAV-2 flags indicating original catalogues:
B = VLBA
E = SDSS
I = Hewitt and Burbidge, 1993ApJS...87..451H 1993ApJS...87..451H, Cat. VII/158
M = Veron-Cetty & Veron compilation, 2010A&A...518A..10V 2010A&A...518A..10V, Cat. VII/258
Note (1): Table number as follows:
3 = Binary quasars of the LQAC-2 with the highest redshifts
4 = Binary quasars with the lowest redshifts (two of them form a triplet)
5 = Binary quasars with the brightest magnitude U for one of their components
6 = Binary quasars with the smallest separation
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [LQAC_]
6- 20 A15 --- QSO1/2 Quasar names (NNN+NNN_NNN/NNN)
22- 26 F5.2 mag U1mag ?=0 U magnitude of first quasar
28- 32 F5.2 mag U2mag ?=0 U magnitude of first quasar
34- 40 F7.4 arcsec theta [2/30] Separation angle
42- 46 F5.3 --- z1 Redshift of first quasar
48- 52 F5.3 --- z2 Redshift of second quasar
54- 66 A13 --- Ref1 [A-M -] Reference (1)
68- 80 A13 --- Ref2 [A-M -] Reference (1)
82- 84 I3 --- SeqU [1/160] Sequential number in terms of increasing
magnitude U of the brightest component
86- 88 I3 --- Seqz [1/160] Sequential number in terms of decreasing
value of z
90-100 A11 --- QSO1 First QSO name (NNN+NNN_NNN)
101 A1 --- --- [/]
102-112 A11 --- QSO2 Second QSO name (NNN+NNN_NNN)
--------------------------------------------------------------------------------
Note (1): Flag of the catalogues in which each component can be found:
A = ICRF2 (Ma et al., 2009, IERS, Technical Note No. 35;
Boboltz et al., 2010, Bull. of the Am. Astron. Soc. 42,512)
B = VLBI (VCS Petrov et al., Cat. J/AJ/136/580, version 2010c)
C = VLA (Cat. J/ApJS/141/13, J/AJ/126/2562, J/AJ/129/1163, J/AJ/131/1872)
D = JVAS (Patnaik et al., Cat. VIII/60)
E = SDSS DR8, http://www.sdss8.org
F = 2QZ (Croom et al., Cat. VII/241)
G = 2df-SDSS (2df-SDSS LRG and QSO survey (2009));
da Angela et al., 2008MNRAS.383..565D 2008MNRAS.383..565D;
LRG: Cannon et al., Cat. J/MNRAS/372/425;
QOS: Croom et al., Cat. J/MNRAS/392/19
H = FIRST (Becker et al., Cat. VIII/71)
I = Hewitt with corrected position (Hewitt and Burbridge, VII/158)
J = 2MASS (just to complete magnitude) (Cutri et al., Cat. II/246)
K = GSC2.3 (just to complete magnitude) (Lasker et al., Cat. I/305)
L = B1.0 (just to complete magnitude) (Monet et al., Cat. I/284)
M = VV10 - QSO SDSS DR1 to DR7 (Veron and Veron 2010, Cat. VII/258)
--------------------------------------------------------------------------------
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 02-Jul-2014