J/ApJS/245/17 X-shaped radio galaxies from FIRST (Yang+, 2019)
Extended catalog of winged or X-shaped radio sources from the FIRST survey.
Yang X., Joshi R., Gopal-Krishna, An T., Ho L.C., Wiita P.J., Liu X.,
Yang J., Wang R., Wu X.-B., Yang X.
<Astrophys. J. Suppl. Ser., 245, 17 (2019)>
=2019ApJS..245...17Y 2019ApJS..245...17Y
ADC_Keywords: Galaxies, radio; Radio continuum; Magnitudes, absolute; QSOs;
Redshifts; Photometry, SDSS; Morphology; Active gal. nuclei
Keywords: Active galactic nuclei; Catalogs; Jets; Quasars;
Radio continuum emission; Surveys
Abstract:
We present a catalog of 290 "winged" or X-shaped radio galaxies (XRGs)
extracted from the latest (2014 December 17) data release of the "Very
Large Array Faint Images of the Radio Sky at Twenty centimeter". We
have combined these radio images with their counterparts in the TIFR
GMRT sky survey at 150MHz, in an attempt to identify any low surface
brightness radio emission present in these sources. This has enabled
us to assemble a sample of 106 "strong" XRG candidates and 184
"probable" XRG candidates whose XRG designation needs to be verified
by further observations. The present sample of 290 XRG candidates is
almost twice as large as the number of XRGs currently known.
Twenty-five of our 290 XRG candidates (9 "strong" and 16 "probable")
are identified as quasars. Double-peaked narrow emission lines are
seen in the optical spectra of three of the XRG candidates (two
"strong" and one "probable"). Nearly 90% of the sample is located in
the FR II domain of the Owen-Ledlow diagram. A few of the strong XRG
candidates have a rather flat radio spectrum (spectral index α
flatter than -0.3) between 150MHz and 1.4GHz, or between 1.4 and 5GHz.
Since this is not expected for lobe-dominated extragalactic radio
sources (like nearly all known XRGs), these sources are particularly
suited for follow-up radio imaging and near-simultaneous measurement
of the radio spectrum.
Description:
We have assembled the present catalog of 290 "winged" or X-shaped
radio galaxy (XRG) candidates by searching in the latest VLA FIRST
survey data release version 14Dec17 (see VIII/92). This version covers
10575deg2 of the sky and contains 946432 radio sources, including
those reported in the earlier data releases from 1993 through 2011.
The survey achieved a typical rms noise of 0.15mJy and a resolution of
∼5" at 1.4GHz.
Images from FIRST were combined with the 150MHz radio continuum images
reported in Intema+, 2017, J/A+A/598/A78 ; see Section 3 for further
explanations.
The radio contours were then overlaid on the Sloan Digital Sky Survey
(SDSS) SDSS i-band and/or Digital Sky Survey (DSS) red filter image of
the source. See Section 4 for further explanations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 99 106 "Strong" X-shaped radio source candidates
table3.dat 87 184 "Probable" X-shaped radio source candidates
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See also:
VIII/52 : The MIT-Green Bank 5GHz Survey (Bennett+, 1986-91)
VIII/13 : A new catalog of 53522 4.85GHz sources (Becker+ 1991)
VIII/38 : The Parkes-MIT-NRAO 4.85GHz (PMN) Surveys (Wright+, 1996)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/51 : the FIRST Survey, version 1998Feb (White+ 1998)
VIII/59 : the FIRST Survey, version 1999Jul (White+ 1999)
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+, 2015)
J/ApJS/80/137 : Southern Extragalactic Radio Sources (Jones+, 1992)
J/AJ/133/2097 : FIRST "Winged" & X-shaped radio source cand. (Cheung, 2007)
J/ApJS/181/548 : X-shaped radio sources. II. New redshifts (Cheung+, 2009)
J/ApJS/194/31 : Morphology for groups in the FIRST database (Proctor, 2011)
J/ApJS/199/27 : The ATLBS Extended Source Sample (Saripalli+, 2012)
J/ApJS/220/7 : Abundance of X-shaped radio sources. I. VLA (Roberts+, 2015)
J/A+A/598/A78 : The GMRT 150MHz all-sky radio survey (Intema+, 2017)
J/ApJ/852/47 : "X-shaped" radio sources. I. VLA imaging (Roberts+, 2018)
J/ApJ/852/48 : "X-shaped" radio sources. II. (Saripalli+, 2018)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table[23].dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- SName Short name (JHHMM+DDMM)
12 A1 --- f_SName a: Also appeared in Proctor (2011, J/ApJS/194/31)
14- 15 I2 h RAh Hour of right ascension (J2000)
17- 18 I2 min RAm Minute of right ascension (J2000)
20- 24 F5.2 s RAs Second of right ascension (J2000)
26 A1 --- DE- Sign of declination (J2000)
27- 28 I2 deg DEd Degree of declination (J2000)
30- 31 I2 arcmin DEm Arcminute of declination (J2000)
33- 36 F4.1 arcsec DEs Arcsecond of declination (J2000)
38- 42 F5.3 --- z [0.01/1.4]? Redshift from NED and/or SDSS
44- 49 A6 --- n_z Note on z (1)
51- 55 F5.2 mag rmag [12/24]? SDSS r-band apparent (AB) magnitude
of the host galaxy
57- 62 F6.2 mag RMag [-26/0]? Absolute R-band magnitude
of the host galaxy
64- 68 F5.3 Jy S0.15 [0.09/9.2]? Integrated 150MHz flux density
from TGSS_ADR1 (Intema+ 2017, J/A+A/598/A78) (2)
70- 74 F5.3 Jy S1.4 [0.02/1.2]? Integrated 1.4GHz flux density
from NVSS (Condon+ 1998, VIII/65) (3)
76- 80 F5.3 Jy S5 [0.02/0.7]? Integrated 5GHz/4.85GHz
flux density
82- 87 A6 --- r_S5 References for 5GHz/4.85 GHz flux density (4)
89- 93 F5.2 --- alph1 [-1.2/-0.18]? Spectral index between
150MHz and 1.4GHz (only for Table 2)
95- 99 F5.2 --- alph2 [-1.25/1.07]? Spectral index between
1.4GHz and 5GHz/4.85GHz (only for Table 2)
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Note (1): Redshift quality flag as follows:
PHOT = photometric redshift;
SPEC = spectroscopic redshift;
SPEC/Q = quasar.
Note (2): The uncertainty is 10% of the total flux density.
Note (3): The uncertainty is 3% of the total flux density.
Note (4): References as follows:
NRAO = NRAO Green Bank 300 Foot 4.85GHz survey (Becker+ 1991, VIII/13)
PMN = the Parkes-MIT-NRAO 4.85GHz Surveys (PMN; Griffith+ 1995, VIII/38)
MIT-GB = the MIT-Green Bank 5GHz Survey (Bennett+ 1986, VIII/52)
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 24-Mar-2020