J/ApJS/267/37 A Quick Look at the 3GHz radio sky. II. DRAGNs (Gordon+, 2023)
A Quick Look at the 3GHz radio sky.
II. Hunting for DRAGNs in the VLA Sky Survey.
Gordon Y.A., Rudnick L., Andernach H., Morabito L.K., O'Dea C.P.,
Achong K.-M., Baum S.A., Bayona-Figueroa C., Hooper E.J., Mingo B.,
Morris M.E., Vantyghem A.N.
<Astrophys. J. Suppl. Ser., 267, 37 (2023)>
=2023ApJS..267...37G 2023ApJS..267...37G
ADC_Keywords: Galaxies, radio; Active gal. nuclei; Redshifts; Galaxies, radius;
Photometry, infrared
Keywords: Radio astronomy ; Radio galaxies ; Giant radio galaxies ;
Extragalactic radio sources ; Active galactic nuclei
Abstract:
Active galactic nuclei (AGNs) can often be identified in radio images
as two lobes, sometimes connected to a core by a radio jet. This
multicomponent morphology unfortunately creates difficulties for
source finders, leading to components that are (a) separate parts of a
wider whole, and (b) offset from the multiwavelength cross
identification of the host galaxy. In this work we define an
algorithm, DRAGNhunter, for identifying double radio sources
associated with AGNs (DRAGNs) from component catalog data in the first
epoch Quick Look images of the high-resolution (∼3" beam size) Very
Large Array Sky Survey (VLASS). We use DRAGNhunter to construct a
catalog of >17000 DRAGNs in VLASS for which contamination from
spurious sources is estimated at ∼11%. A "high-fidelity" sample
consisting of 90% of our catalog is identified for which contamination
is <3%. Host galaxies are found for ∼13000 DRAGNs as well as for an
additional 234,000 single-component radio sources. Using these data,
we explore the properties of our DRAGNs, finding them to be typically
consistent with Fanaroff-Riley class II sources and to allow us to
report the discovery of 31 new giant radio galaxies identified using
VLASS.
Description:
For this work we make use of the catalog of components in the Quick
Look images of the Karl G. Jansky Very Large Array (VLA) Sky Survey
(VLASS; Lacy+ 2020PASP..132c5001L 2020PASP..132c5001L) epoch 1 presented in
Gordon+ (2021, J/ApJS/255/30). The median beam size of VLASS in
epoch 1 is 2.9", the smallest of any near-all-sky radio continuum
survey to date.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 52 31 Newly discovered giant radio galaxies in Very Large
Array Sky Survey (VLASS) identified by DRAGNhunter
table3.dat 21 1836 Results of the visual inspection of triple sources
identified by DRAGNhunter
table5.dat 247 595375 Source and host information
table6.dat 347 17724 Double radio sources associated with AGN (DRAGN)
properties
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS Team, 1998-2003)
VII/249 : 6dF-DR2 Galaxy Survey (Jones+, 2005)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
VII/292 : DESI Legacy Imaging Surveys DR8 (Duncan, 2022)
J/A+A/374/861 : Positions of giant radio galaxies (Schoenmakers+ 2001)
J/ApJ/586/794 : Multiwavelength luminosities of galaxies (Bell, 2003)
J/AJ/128/1974 : The VLA-COSMOS survey (Schinnerer+, 2004)
J/MNRAS/362/9 : Radio-loud AGN in SDSS (Best+, 2005)
J/MNRAS/381/211 : Radio galaxies in the 2SLAQ LRG Survey (Sadler+, 2007)
J/ApJS/172/46 : VLA-COSMOS survey. II. (Schinnerer+, 2007)
J/MNRAS/401/1429 : WiggleZ dark energy survey (DR1) (Drinkwater+, 2010)
J/MNRAS/413/971 : Galaxy And Mass Assembly (GAMA) DR1 (Driver+, 2011)
J/ApJS/194/31 : Morphology for groups in FIRST database (Proctor, 2011)
J/MNRAS/421/1569 : Properties of 18286 SDSS radio galaxies (Best+, 2012)
J/ApJS/199/26 : The 2MASS Redshift Survey (2MRS) (Huchra+, 2012)
J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)
J/MNRAS/438/1149 : Radio-loud AGN complete samples with WISE (Gurkan+, 2014)
J/MNRAS/462/1910 : H-ATLAS NGP LOFAR radio catalogue (Hardcastle+, 2016)
J/MNRAS/464/1306 : LARGESS survey (Ching+, 2017)
J/A+A/598/A104 : LOFAR Two-metre Sky Survey (Shimwell+, 2017)
J/A+A/602/A1 : VLA-COSMOS 3 GHz Large Project (Smolcic+, 2017)
J/MNRAS/474/3875 : Galaxy And Mass Assembly (GAMA): DR3 (Baldry+, 2018)
J/MNRAS/474/4151 : WiggleZ Dark Energy Survey final DR (Drinkwater+, 2018)
J/ApJS/238/9 : Cat. of giant radio sources known to date (Kuzmicz+, 2018)
J/AJ/157/126 : Distortion of radio gal. by galaxy clusters (Garon+, 2019)
J/MNRAS/485/2710 : Radio jets associated with gal. outflows (Jarvis+, 2019)
J/A+A/622/A1 : LOFAR Two-metre Sky Survey DR1 sources (Shimwell+, 2019)
J/A+A/642/A153 : SAGAN. I. Multi-wavelength studies (Dabhade+, 2020)
J/A+A/635/A5 : LoTSS giant radio galaxies. I. (Dabhade+, 2020)
J/ApJS/247/53 : ROGUE. I. SDSS gal. with FIRST (Koziel-Wierzbowska+, 2020)
J/other/Galax/9.99 : Giant Radio Galaxies in RACS (Andernach+, 2021)
J/ApJS/255/30 : VLASS QL Ep.1 Catalog, CIRADA version (Gordon+, 2021)
J/other/PASA/38.58 : Rapid ASKAP Continuum Survey. II. RACS cat. (Hale+, 2021)
J/ApJS/253/25 : Giant radio QSOs from SDSS, FIRST & NVSS (Kuzmicz+, 2021)
J/A+A/648/A102 : FR-type radio sources at 3GHz (Vardoulaki+, 2021)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
J/A+A/672/A163 : Properties of the 2060 giant radio galaxies (Oei+, 2023)
http://science.nrao.edu/vlass : VLA Sky Survey home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Position-based name (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.1 mJy Flux [23.3/353.5] Flux density (1)
27- 29 I3 arcsec LAS [86/169] Largest angular size
31- 35 F5.3 --- z [0.516/1.491] Redshift
37- 41 A5 --- f_z Redshift type ("spec" or "photo")
43- 47 F5.2 W/Hz logL3GHz [25.53/27.38] log of 3GHz luminosity
49- 52 I4 kpc LLS [700/1428] Projected largest linear size
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Note (1): The flux density measurements presented in this table are
higher than the cataloged values by a factor of 1/0.87 in order to
account for the systematic underestimation of flux densities in the
VLASS Quick Look component catalog (see Section 3 of
Gordon+ 2021, J/ApJS/255/30). It is these values that have been used to
estimate the radio luminosities.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Position-based (JHHMMSS.ss+DDMMSS.s) name
of the triple source
21- 21 I1 --- Flag [0/1] Artifact Flag: 0=passed visual inspect;
1=artifact
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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- 11 A11 --- Cat "VLASS1QLCIR" or nothing (1)
13- 31 A19 --- Name Position-based (JHHMMSS.ss+DDMMSS.s) name (1)
33- 42 F10.6 deg RAdeg Radio source right ascension (J2000)
44- 53 F10.6 deg DEdeg Radio source declination (J2000)
55- 63 F9.3 mJy Flux [0.02/10055] Total flux density of the radio
source (G1)
65- 71 F7.3 mJy e_Flux [0.005/105] Uncertainty in Flux
73- 79 F7.3 arcsec LAS [0/238] Largest angular extent
81- 85 F5.3 arcsec e_LAS [0/5] Uncertainty in LAS
87 A1 --- Type Is the source a DRAGN (D) or
single-component (S) source?
89 I1 --- Q [0/1] Source quality flag (>0 is suspect) (G2)
91- 109 A19 --- WISEA AllWISE Host ID
111- 120 F10.6 deg RAAdeg ? Host AllWISE right ascension (J2000)
122- 131 F10.6 deg DEAdeg ? Host AllWISE declination (J2000)
133- 138 F6.3 arcsec SepWISEA [0.002/24]? Angular separation between radio
source and AllWISE host
140- 149 F10.3 --- LR [1.8/241322]? Likelihood ratio of the host
ID match
151- 157 F7.5 --- Rel [2e-5/1.01]? Probability the host ID is
correct
159- 160 I2 --- QHost [-2/1]? Host ID flag (>0 is suspect) (G3)
162- 167 F6.3 mag W1mag [3.9/19]? Vega magnitude in WISE W1 band
169- 173 F5.3 mag e_W1mag [0.008/0.3]? Uncertainty in W1mag
175- 180 F6.3 mag W2mag [0/18.4]? Vega magnitude in WISE W2 band
182- 186 F5.3 mag e_W2mag [0/0.6]? Uncertainty in W2mag
188- 193 F6.3 mag W3mag [-6.3/14]? Vega magnitude in WISE W3 band
195- 199 F5.3 mag e_W3mag [0/0.6]? Uncertainty in W3mag
201- 206 F6.3 mag W4mag [-5.7/10.4]? Vega magnitude in WISE W4 band
208- 212 F5.3 mag e_W4mag [0/0.6]? Uncertainty in W4mag
214- 221 F8.5 --- z [-0.06/7.02]? Host redshift
223- 231 F9.5 --- e_z [-6/937]? Uncertainty in z
233- 237 A5 --- f_z Redshift type (spec/photo)
239- 247 A9 --- r_z Survey redshift was obtained from (2)
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Note (1): For single-component sources the name comes from
the VLASS Quick Look component catalog (Gordon+ 2021, J/ApJS/255/30 ;
<VLASS1QLCIR JHHMMSS.ss+DDMMSS.s> in Simbad).
For DRAGNs the Name is a Julian name of the format Jhhmmss.ss+ddmmss.s
without a catalog prefix.
Note (2): Survey redshift sources as follows:
2MRS = two-Micron All Sky Survey redshift survey,
Huchra+ (2012, J/ApJS/199/26)
2dFGRS = two-degree Field Galaxy Redshift Survey,
Colless+ (2001MNRAS.328.1039C 2001MNRAS.328.1039C ; Cat. VII/250)
6dFGS = six-degree Field Galaxy Survey, Jones+ (2004MNRAS.355..747J 2004MNRAS.355..747J ;
2005PASA...22..277J 2005PASA...22..277J ; Cat. VII/249)
GAMA = 3rd data release, Galaxy and Mass Assembly survey,
Driver+ (2011, J/MNRAS/413/971 ; Baldry+ 2018, J/MNRAS/474/3875)
LS-DR8 = Dark Energy Survey Spectroscopic Instrument Legacy Surveys (DR8)
photo-z catalog, Duncan (2022MNRAS.512.3662D 2022MNRAS.512.3662D ; Cat. VII/292)
SDSS-DR16 = Sloan Digital Sky Survey Data Release 16 (DR16),
Ahumada+ (2020ApJS..249....3A 2020ApJS..249....3A ; Cat. V/154)
WiggleZ = WiggleZ survey, Drinkwater+ (2010, J/MNRAS/401/1429 ;
2018, J/MNRAS/474/4151)
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Position-based (JHHMMSS.ss+DDMMSS.s)
21- 29 F9.5 deg RAdeg DRAGN best Right Ascension (J2000)
31- 39 F9.5 deg DEdeg [-40.1/90] DRAGN best Declination (J2000)
41- 48 F8.3 mJy Flux [2.7/8747] Total flux density of the
radio source (G1)
50- 55 F6.3 mJy e_Flux [0.3/88] Uncertainty in Flux
57- 63 F7.5 --- CoreProm [4e-5/0.99]? Fraction of Flux from Core
65- 71 F7.5 --- e_CoreProm [1e-5/0.09]? Uncertainty in CoreProm
73- 80 F8.4 --- Lobe1/Lobe2 [0.003/353] Flux ratio of Lobe-1/Lobe-2
82- 89 F8.4 --- e_Lobe1/Lobe2 [0.0007/108] Uncertainty in Lobe1/Lobe2
91- 96 F6.2 arcsec LAS [7/238] Largest angular extent
98- 101 F4.2 arcsec e_LAS [0.01/5] Uncertainty in LAS
103- 107 F5.2 deg Misalign1 [0/90] Relative misalignment of Lobe-1 (1)
109- 114 F6.2 deg e_Misalign1 [0.02/180] Uncertainty in Misalign1
116- 120 F5.2 deg Misalign2 [0/90] Relative misalignment of Lobe-2 (1)
122- 127 F6.2 deg e_Misalign2 [0.05/180] Uncertainty in Misalign2
129- 133 F5.2 deg AvgMisalign [0.08/89.5] Mean misalignment of lobes
135- 140 F6.2 deg e_AvgMisalign [0.1/255] Uncertainty in MeanMisalign
142- 172 A31 --- Lobe1 Component name of Lobe1
174- 204 A31 --- Lobe2 Component name of Lobe2
206- 236 A31 --- Core Component name of Core
238- 246 F9.5 deg RACdeg ? Core R.A. (J2000)
248- 256 F9.5 deg DECdeg ? Core Decl. (J2000)
258- 266 F9.5 deg RALdeg Lobes median R.A. (J2000)
268- 276 F9.5 deg DELdeg Lobes median Decl. (J2000)
278- 286 F9.5 deg RAFdeg Flux weighted central R.A. (J2000) of
lobes
288- 296 F9.5 deg DEFdeg Flux weighted central Decl. (J2000) of
lobes
298 I1 --- Q [0/1] Source quality flag (>0 is suspect)
(G2)
300- 318 A19 --- WISEA AllWISE Host ID
320- 325 F6.3 arcsec SepWISEA [0.005/24]? Angular separation between
radio source and AllWISE host
327- 336 F10.3 --- LR [1.8/241322]? Likelihood ratio of the
host ID match
338- 344 F7.5 --- Rel [2e-5/1.01]? Probability the host ID is
correct
346- 347 I2 --- QHost [-2/1]? Host ID flag (>0 is suspect) (G3)
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Note (1): Components with low aspect ratios (nearly circular
geometry) can have large uncertainties in their measured
misalignments. Users are advised to make use of the appropriate
uncertainty measurements provided (e_Misalign#) if using these values.
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Global notes:
Note (G1): This is the sum of the cataloged fluxes of all associated
components. The flux-scaling correction of 1/0.87 recommended in
Gordon+ 2021, J/ApJS/255/30 has not been applied to these values and
is left to the discretion of the end-user.
Note (G2): Set to 1 if Type="D" and either Lobefluxratio<0.1 or
Lobefluxratio>10 or LAS/ELAS<20. For all other sources this
flag is set to 0.
Note (G3): Set to -2 if the LR identified host of a DRAGN is
co-located with a radio core, -1 if the LR identified host of a
DRAGN has been replaced by a host candidate coincident with a
core, 0 for single component-sources and DRAGNs without a radio
core, and 1 for DRAGNs with a radio core that is not co-located
with a host candidate.
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History:
From electronic version of the journal
References:
Gordon et al. Paper I. 2021ApJS..255...30G 2021ApJS..255...30G Cat. J/ApJS/255/30
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Nov-2023