J/ApJ/901/3 Blazar Radio and Optical Survey (BROS) (Itoh+, 2020)
Blazar Radio and Optical Survey (BROS): a catalog of blazar candidates showing
flat radio spectrum and their optical identification in Pan-STARRS1 surveys.
Itoh R., Utsumi Y., Inoue Y., Ohta K., Doi A., Morokuma T., Kawabata K.S.,
Tanaka Y.T.
<Astrophys. J., 901, 3-3 (2020)>
=2020ApJ...901....3I 2020ApJ...901....3I (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; BL Lac objects ; Radio sources
Keywords: blazars - radio active galactic nuclei - catalogs
Abstract:
Utilizing the latest and the most sensitive radio and optical
catalogs, we completed a new blazar candidate catalog, Blazar Radio
and Optical Survey (BROS), which includes 88211 sources located at
decl. δ>-40° and outside the galactic plane (|b|>10°).
We list compact flat-spectrum radio sources of α>-0.6 (α
is defined as Fν∝να) from 0.15GHz TGSS to
1.4GHz NVSS catalogs. We further identify optical counterparts of the
selected sources by cross-matching with Pan-STARRS1 photometric data.
Color-color and color-magnitude plots for the selected BROS sources
clearly show two distinct populations, a "quasar-like" population
consisting of both flat-spectrum radio quasars and BL Lac type
objects. On the other hand, an "elliptical-like" population of mostly
BL Lac type objects is buried in the elliptical galaxy. The latter
population is also reported in previous catalogs, but the BROS catalog
provided a new larger sample of this population, due to the lower
radio flux threshold of our selection. Model calculations show that
the "elliptical-like" population consists of elliptical galaxies
located at redshift z≤0.5, which is also supported by the logN-logS
distribution of the power-law index of 1.49±0.05. This BROS catalog
is useful for identifying the electromagnetic counterparts of
ultra-high-energy cosmic rays and PeV neutrinos recently detected by
IceCube, as well as nearby BL Lac objects detectable by future
high-sensitivity TeV telescopes, such as the Cherenkov Telescope
Array.
Description:
BROS (Blazar Radio and Optical Survey) is a new blazar candidate
catalog, which includes 88,211 sources located at declination
DE>-40° and outside the Galactic Plane |b|>10°. We list
compact flat-spectrum radio sources of alpha>-0.6 from 0.15GHz TGSS
and 1.4GHz NVSS catalogs. We further identify optical counterparts of
the selected sources by cross-matching with the Pan-STARRS1
photometric data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 325 88211 BROS Catalog
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See also:
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/A+A/598/A78 : The GMRT 150MHz all-sky radio survey (TGSS) (Intema+, 2017)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- BROS-ID source ID (BROS-ID)
19- 31 F13.9 deg RAdeg Right ascension (J2000) from TGSS-NVSS catalog
(spindx-RA)
33- 45 F13.9 deg DEdeg Declination (J2000) from TGSS-NVSS catalog
(spindx-Dec)
47- 59 F13.9 Jy FTGSS TGSS 150MHz total flux (spindx-TGSS-Flux)
61- 71 F11.9 Jy e_FTGSS TGSS 150MHz total flux error
(spindx-TGSS-Flux-error)
73- 84 F12.9 Jy FNVSS NVSS 1.4GHz total flux (spindx-NVSS-Flux)
86- 96 F11.9 Jy e_FNVSS NVSS 1.4GHz total flux error
(spindx-NVSS-Flux-error)
98-105 F8.5 --- SpIndex Spectral index between 0.15GHz and 1.4GHz
(spindx-Spectral-Index)
107-115 F9.6 --- e_SpIndex Spectral index error
(spindx-Spectral-Index-error)
117 A1 --- Flag [QEGB] Source type flag (SourceFlag) (1)
119-126 F8.6 --- Rcomp Radio compactness defined as
totalflux/peakflux (NVSS)
(radio-Compactness)
128-136 F9.7 --- e_Rcomp Radio compactness error
(radio-Compactness-error)
138-145 F8.3 --- Ocomp ?=-999 Optical compactness defined as
MPSF-MKron (PS1, i- band)
(optical-Compactness)
147-155 F9.4 --- e_Ocomp ?=-999 Optical compactness error
(optical-Compactness-error)
157-167 F11.6 arcsec Sep ?=-999 Source separation angle between
TGSS-NVSS and PS1 catalog position
(PS1-BROS-separation)
169-182 F14.9 deg RAPdeg ?=-999 r-band R.A. position (PS1-r-RA)
184-197 F14.9 deg DEPdeg ?=-999 r-band Decl. position (PS1-r-Dec)
199-207 F9.4 mag gmagK ?=-999 g-band Kron magnitude (PS1-g-Kronmag)
209-218 F10.5 mag e_gmagK ?=-999 g-band Kron magnitude error
(PS1-g-Kronmag-error)
220-228 F9.4 mag gmagP ?=-999 g-band PSF magnitude (PS1-g-PSFmag)
230-240 F11.5 mag e_gmagP ?=-999 g-band PSF magnitude error
(PS1-g-PSFmag-error)
242-250 F9.4 mag rmagK ?=-999 r-band Kron magnitude (PS1-r-Kronmag)
252-261 F10.5 mag e_rmagK ?=-999 r-band Kron magnitude error
(PS1-r-Kronmag-error)
263-271 F9.4 mag rmagP ?=-999 r-band PSF magnitude (PS1-r-PSFmag)
273-283 F11.5 mag e_rmagP ?=-999 r-band PSF magnitude error
(PS1-r-PSFmag-error)
285-293 F9.4 mag imagK ?=-999 i-band Kron magnitude (PS1-i-Kronmag)
295-304 F10.5 mag e_imagK ?=-999 i-band Kron magnitude error
(PS1-i-Kronmag-error)
306-314 F9.4 mag imagP ?=-999 i-band PSF magnitude (PS1-i-PSFmag)
316-325 F10.5 mag e_imagP ?=-999 i-band PSF magnitude error
(PS1-i-PSFmag-error)
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Note (1): Source type flag as follows:
Q = source have a PS1 candidate and not classified as GPS source
E = source, which is located in a quasar-like (elliptical-like) population
G = GPS source
B = source that do not have a PS1-candidate and not classified as GPS source
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Acknowledgements:
Ryosuke Itoh, itoh(at)bao.city.ibara.okayama.jp
(End) Patricia Vannier [CDS] 10-Mar-2021