J/ApJS/220/7 Abundance of X-shaped radio sources. I. VLA survey (Roberts+, 2015)
The abundance of X-shaped radio sources.
I. VLA survey of 52 sources with off-axis distortions.
Roberts D.H., Cohen J.P., Lu J., Saripalli L., Subrahmanyan R.
<Astrophys. J. Suppl. Ser., 220, 7 (2015)>
=2015ApJS..220....7R 2015ApJS..220....7R
ADC_Keywords: Galaxies, radio; Radio continuum; Redshifts
Keywords: galaxies: active ; gravitational waves ; radio continuum: galaxies
Abstract:
Cheung (2007, J/AJ/133/2097) identified a sample of 100 candidate
X-shaped radio galaxies using the NRAO FIRST survey; these are
small-axial-ratio extended radio sources with off-axis emission. Here,
we present radio images of 52 of these sources that have been made
from archival Very Large Array data with resolution of about 1".
Fifty-one of the 52 were observed at 1.4GHz, 7 were observed at 1.4
and 5GHz, and 1 was observed only at 5GHz. We also present overlays of
the Sloan Digital Sky Survey red images for 48 of the sources, and
DSS-II overlays for the remainder. Optical counterparts have been
identified for most sources, but there remain a few empty fields. Our
higher resolution VLA images along with FIRST survey images of the
sources in the sample reveal that extended extragalactic radio sources
with small axial ratios are largely (60%) cases of double radio
sources with twin lobes that have off-axis extensions, usually with
inversion-symmetric structure. The available radio images indicate
that at most 20% of sources might be genuine X-shaped radio sources
that could have formed by a restarting of beams in a new direction
following an interruption and axis flip. The remaining 20% are in
neither of these categories.
Description:
The NRAO Data Archive was searched for historical VLA data on the 100
sources in Cheung's sample (2007, J/AJ/133/2097). We used all existing
L-band observations in the A-array and C-band observations in the
B-array. Thus the resulting images had a resolution of about one arcsec.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 52 Observed source properties and classifications
table2.dat 27 52 Derived source properties
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See also:
J/AJ/133/2097 : FIRST "Winged" and X-shaped radio source cand. (Cheung, 2007)
J/ApJS/181/548 : X-shaped radio sources cand. II. New redshifts (Cheung+, 2009)
J/ApJ/852/47 : X-shaped radio sources. I. VLA imaging (Roberts+, 2018)
J/ApJ/852/48 : X-shaped radio sources. II. Sample data (Saripalli+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Set Set (G1)
7- 16 A10 --- [C2007] Name (JHHMM+DDMM)
18 A1 --- f_[C2007] [g] Flag on Name (1)
20- 21 I2 --- Fig [1/52] Figure number
23- 24 A2 --- Type Type: G=narrow line radio galaxy; or
BG=broad line radio galaxy
26- 31 F6.4 --- z [0.03/0.9]? Redsfhit (2)
33- 36 F4.2 --- z2 [0.26]? Second redshift for J1210-0341 (2)
38- 52 A15 mJy Score Score from this work
54- 57 I4 mJy Stot [12/1889] Stot from this work
58 A1 --- u_Stot [?] Uncertainty flag on Stot
60- 63 I4 mJy Stot2 [36/2385] Integrated 1.4GHz flux density
from Cheung (2007, J/AJ/133/2097)
65- 67 I3 arcsec theta [24/170] Largest angular size θmax
69- 83 A15 --- Edges? Inner edges?
85- 87 A3 --- Em? Large-scale emission resolved out? (3)
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Note (1):
g = For these sources absence of core or ID and poor radio maps disallowed
examining radio structural properties.
Note (2): All redshifts from Cheung (2007, J/AJ/133/2097) or
Cheung+ (2009, J/ApJS/181/548).
Note (3): Visibility less than 0.5.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Set Set (G1)
7- 16 A10 --- [C2007] Name (JHHMM+DDMM)
18- 20 I3 kpc Lproj [28/950]? Projected size
22- 22 A1 % l_fcore Limit flag on fcore
23- 27 F5.2 % fcore [0.03/13]? Core fraction in percent, L band
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Global notes:
Note (G1): Group as follows:
iEnds = Sources with "bends from inner ends"
oEnds = Sources with "bends from outer ends"
other = other sources.
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History:
From electronic version of the journal
References:
Roberts et al. 2015ApJ...810L...6R 2015ApJ...810L...6R
Roberts et al. Paper I. 2015ApJS..220....7R 2015ApJS..220....7R This catalog
(End) Emmanuelle Perret [CDS] 24-Jul-2018