J/ApJS/242/4 Two new catalogs of blazar candidates (D'Abrusco+, 2019)
Two new catalogs of blazar candidates in the WISE Infrared sky.
D'Abrusco R., Alvarez Crespo N., Massaro F., Campana R., Chavushyan V.,
Landoni M., La Franca F., Masetti N., Milisavljevic D., Paggi A., Ricci F.,
Smith H.A.
<Astrophys. J. Suppl. Ser., 242, 4-4 (2019)>
=2019ApJS..242....4D 2019ApJS..242....4D (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Active gal. nuclei ; Photometry, infrared ;
Radio sources
Keywords: BL Lacertae objects: general - catalogs - galaxies: active -
radiation mechanisms: non-thermal
Abstract:
We present two catalogs of radio-loud candidate blazars whose
Wide-Field Infrared Survey Explorer (WISE) mid-infrared colors are
selected to be consistent with the colors of confirmed
γ-ray-emitting blazars. The first catalog is the improved and
expanded release of the WISE Blazar-like Radio-Loud Sources (WIBRaLS)
catalog presented by D'Abrusco et al. It includes sources detected in
all four WISE filters, spatially cross-matched with radio sources in
one of three radio surveys and radio-loud based on their q22
spectral parameter. WIBRaLS2 includes 9541 sources classified as BL
Lacs, flat-spectrum radio quasars, or mixed candidates based on their
WISE colors. The second catalog, called KDEBLLACS, based on a new
selection technique, contains 5579 candidate BL Lacs extracted from
the population of WISE sources detected in the first three WISE
passbands ([3.4], [4.6], and [12]) only, whose mid-infrared colors are
similar to those of confirmed, γ-ray BL Lacs. Members of
KDBLLACS are also required to have a radio counterpart and be
radio-loud based on the parameter q12, defined similarly to the
q22 used for the WIBRaLS2. We describe the properties of these
catalogs and compare them with the largest samples of confirmed and
candidate blazars in the literature. We cross-match the two new
catalogs with the most recent catalogs of γ-ray sources detected
by the Fermi Large Area Telescope. Since spectroscopic observations of
candidate blazars from the first WIBRaLS catalog within the
uncertainty regions of γ-ray unassociated sources confirmed that
∼90% of these candidates are blazars, we anticipate that these new
catalogs will again play an important role in the identification of
the γ-ray sky.
Description:
we present two new catalogs of blazar candidates, selected on the
basis of their WISE mid-IR colors, association with a radio
counterpart, and radio-loudness. These new catalogs contain a combined
total of 15196 candidate blazars, including both candidate FSRQs and
BL Lacs, distributed on ∼90% of the sky.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 123 9541 *WIBRaLS2 catalog
table5.dat 89 5580 KDEBLLACS catalog
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Note on table3.dat: WIBRaLS catalog supersedes the original WIBRaLS1 (Paper I,
D'Abrusco et al. 2014ApJS..215...14D 2014ApJS..215...14D) catalog.
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/81 : Sydney University Molonglo Sky Survey (SUMSS V2.1) (Mauch+ 2008)
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
II/328 : AllWISE Data Release (Cutri+ 2013)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- WISE AllWISE name
21- 31 F11.7 deg RAdeg Right Ascension of AllWISE source (J2000)
33- 43 F11.7 deg DEdeg Declination of AllWISE source (J2000)
45- 48 F4.2 mag W1-W2 W1-W2 AllWISE color index
50- 53 F4.2 mag W2-W3 W2-W3 AllWISE color index
55- 58 F4.2 mag W3-W4 W3-W4 AllWISE color index
60- 63 F4.2 --- SBZB Score for the BZB (BL Lac) region of
the locus (1)
65- 68 F4.2 --- SMIX Score for the Mixed region of the locus (1)
70- 73 F4.2 --- SBZQ Score for the BZQ (FSRQ) region of
the locus (1)
75 A1 --- Class [ABCD] Class (2)
77- 81 A5 --- Type Spectral type (3)
83-103 A21 --- Radio Name of the radio counterpart
(NVSS, FIRST or SUMSS)
105-117 F13.7 mJy S Radio flux density (G1)
119-123 F5.2 --- q22 Radio-loudness parameter q22
(q22=log(S22um/Sradio)
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Note (1): The WISE colors of a WISE source and the associated uncertainties are
projected into the PC three-dimensional space, where they define an
"uncertainty ellipsoid." The position and orientation of this
ellipsoid - relative to the model of each cylinder separately - are used to
calculate a numeric value defined between zero and 1.
This normalized distance is then weighted by the volume of the error
ellipsoid, so that two WISE sources placed in the same position relative to
the locus model but with different uncertainties are assigned different
scores.
Note (2): Class as follows (see Section 3.1 of the paper):
A = defined the 90th percentile of the score distribution for the sources
of the locus sample
B = defined by the 60th percentile of the score distribution for the
sources of the locus sample
C = defined by the 20th, 20th percentile of the score distribution for the
sources of the locus sample
D = defined by the 5th percentile of the score distribution for the
sources of the locus sample
Note (3): Spectral type as follows (see Section 3.1 of the paper):
BZB = BL Lac objects, used for AGNs with a featureless optical spectrum
or only with absorption lines of galaxian origin and weak and
narrow emission lines
BZQ = flat-spectrum radio quasars (FSRQ), with an optical spectrum
showing broad emission lines and dominant blazar characteristics
MIXED = mixed between BZB and BZQ
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- WISE AllWISE name
21- 31 F11.7 deg RAdeg Right Ascension of AllWISE source (J2000)
33- 43 F11.7 deg DEdeg Declination of AllWISE source (J2000)
45- 48 F4.2 mag W1-W2 W1-W2 AllWISE color index
50- 53 F4.2 mag W2-W3 W2-W3 AllWISE color index
55- 76 A22 --- Radio Name of the radio counterpart
(NVSS, FIRST or SUMSS)
78- 83 F6.2 mJy S Radio flux density (G1)
85- 89 F5.2 --- q12 Radio-loudness parameter q12
(q12=log(S12um/Sradio)
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Global notes:
Note (G1): Radio flux density at 1.4GHz for NVSS and FIRST sources,
at 843MHz for SUMSS sources.
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Acknowledgements:
Raffaele D'Abrusco, rdabrusc(at)cfa.harvard.edu
References:
D'Abrusco et al., Paper I, 2014ApJS..215...14D 2014ApJS..215...14D, Cat. J/ApJS/215/14
(End) Patricia Vannier [CDS] 15-Jan-2020