J/A+A/699/A338 LoTSS DR2 visual classifications (Horton+, 2025)
Complex morphology and precession indicators of active galactic nuclei jets
in LoTSS DR2.
Horton M.A., Hardcastle M.J., Miley G.K., Tasse C., Shimwell T.
<Astron. Astrophys. 699, A338 (2025)>
=2025A&A...699A.338H 2025A&A...699A.338H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Radio continuum ; Radio sources
Keywords: black hole physics - gravitation - galaxies: active -
galaxies: general - galaxies: jets - radio continuum: galaxies
Abstract:
The LOw Frequency ARray Two-metre Sky Survey second data release
(LoTSS DR2) covers 27% of the northern sky and contains around four
million radio sources. The development of this catalogue involved a
large citizen science project (Radio Galaxy Zoo: LOFAR) with more than
116,000 resolved sources going through visual inspection. We took a
subset of sources with flux density above 75mJy and an angular size of
90" or greater, giving a total of 9985 sources or ∼10% of the
visually inspected sources. We classified these by visual inspection
in terms of broad source type (e.g., Fanaroff-Riley class I or II,
narrow or wide-angle tail, relaxed double), noticeable features
(wings, visible jets, banding, filaments etc), environmental features
(cluster environment, merger, diffuse emission). Our specific aim was
to search for features linked to jet precession, such as a misaligned
jet axis, curvature and multiple hotspots. This combination of
features and morphology allowed us to detect increasingly fine-grained
sub- populations of interesting or unusual sources. We found that 28%
of sources showed evidence of one or more precession indicators, which
could make them candidates for hosting close binary supermassive black
holes. Potential precession signatures occur in sources of all sizes
and luminosities in our sample but appear to favour more massive host
galaxies. Our work greatly expands the sample size and parameter space
of searches for precession signatures in powerful jetted sources. This
work also showcases the diversity of large bright radio sources in the
LOFAR surveys, whether or not precession indicators are present.
Description:
Visual inspection of large, bright sources from LoTSS DR2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 177 9985 Visual classifications and precession indicators
for extended radio sources from LoTSS DR2
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See also:
J/A+A/622/A1 : LOFAR Two-metre Sky Survey DR1 source cat. (Shimwell+, 2019)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
J/A+A/678/A151 : LoTSS DR2 optical IDs (Hardcastle+, 2023)
http://lofar-surveys.org/dr2_release.html : LOFAR surveys website
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Name of the source from the LoTSS DR2 optical
ID catalogue, Cat. J/A+A/678/A151,
ILTJHHMMSS.ss+DDMMSS.s (Source_Name)
25- 47 E23.17 --- zbest ? Best estimate of the source redshift
(z_best)
49- 71 F23.17 kpc Size ? Source physical size in kpc (Size)
73- 95 E23.17 W/Hz L144 ? Source radio luminosity at 144 MHz (L_144)
97-116 F20.16 [Msun] logMassmed ? Base 10 logarithm of source host galaxy
stellar mass estimate (Mass_median)
118 I1 --- f_logMassmed [0/1] Mass quality flag
(do not use if = 0) (flag_mass)
120 I1 --- FRI [0/1] Boolean, source is an FRI (fri)
122 I1 --- FRII [0/1] Boolean, source is an FRII (frii)
124 I1 --- Hybrid [0/1] Boolean, source is a hybrid as
described in the paper (hybrid)
126 I1 --- Spiral [0/1] Boolean, source is a spiral galaxy
(spiral)
128 I1 --- Relaxed [0/1] Boolean, source is a relaxed double
(relaxed)
130 I1 --- Cshaped [0/1] Boolean, source is c-shaped (cshaped)
132 I1 --- Sshaped [0/1] Boolean, source is s-shaped (sshaped)
134 I1 --- Misalign [0/1] Boolean, source is misaligned
(misaligned)
136 I1 --- Wings [0/1] Boolean, source has wings (wings)
138 I1 --- Xshaped [0/1] Boolean, source is x-shaped (xshaped)
140 I1 --- Straight [0/1] Boolean, source has a straight jet
(straight)
142 I1 --- MultHSpot [0/1] Boolean, source has multiple hotspots
in one or both lobes (multihotspots)
144 I1 --- Continuous [0/1] Boolean, source has a continuous jet
(continuous)
146 I1 --- Banding [0/1] Boolean, source shows banding structure
(banding)
148 I1 --- Onesided [0/1] Boolean, source is one-sided (onesided)
150 I1 --- Restarted [0/1] Boolean, source shows signs of having
restarted (restarted)
152 I1 --- Cluster [0/1] Boolean, source is a cluster member
(cluster)
154 I1 --- Merger [0/1] Boolean, source is a merger (merger)
156 I1 --- Diffuse [0/1] Boolean, source has diffuse structure
only (diffuse)
158 I1 --- Unknown [0/1] Boolean, source classification is
unknown (unknown)
160-161 I2 --- FeatureCT Total number of features identified
(featurecount)
163 I1 --- Hasany1 [0/1] Source has any one precession indicator
(hasanyone)
165 I1 --- hasany2 [0/1] Source has any two precession
indicators (hasanytwo)
167 I1 --- Hasall [0/1] Source has all three precession
indicators used in the paper (hasall)
169 I1 --- Has1 [0/1] Source has exactly one precession
indicator (hasexactly1)
171 I1 --- Has2 [0/1] Source has exactly two precession
indicators (hasexactly2)
173 I1 --- SE [0/1] Source shows s symmetry and
misalignment (se)
175 I1 --- MS [0/1] Source shows s symmetry and multiple
hotspots (ms)
177 I1 --- EM [0/1] Source shows multiple hotspots and
misalignment (em)
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Acknowledgements:
Martin Hardcastle, m.j.hardcastle(at)herts.ac.uk
(End) Patricia Vannier [CDS] 28-Apr-2025