J/ApJS/278/34 Morphology of LoTSS DR2 radio galaxies. I. "winged" (Bera+, 2025)
A morphological identification and study of radio galaxies from LoTSS DR2.
I. The "winged" radio galaxies.
Bera S.K., Fang T., Sasmal T.K., Kunert-Bajraszewska M., Chen X.,
Mondal S.
<Astrophys. J. Suppl. Ser., 278, 34 (2025)>
=2025ApJS..278...34B 2025ApJS..278...34B
ADC_Keywords: Galaxies, radio; Active gal. nuclei; Redshifts; Morphology;
Magnitudes; Optical; Galaxies, radius
Keywords: Active galactic nuclei ; Radio galaxies ; Catalogs
Abstract:
We conducted an extensive identification and analysis of various
morphological classes and subclasses of radio galaxies using the
latest high-resolution data from the second data release of the LOFAR
Two-metre Sky Survey. This paper presents the first results of our
large-scale investigation: a new catalog of "winged" radio galaxies
(WRGs). These objects represent a fascinating class of irregular radio
galaxies, characterized by a pair of secondary radio lobes ("wings")
in addition to the primary active lobes. We identified and cataloged
621 new WRGs and 403 additional candidates. Among the confirmed winged
sources, 382 are classified as "X"-shaped radio galaxies, while the
remaining 239 are "Z"-shaped radio galaxies. We also estimated several
basic parameters for these winged sources and performed a
Fanaroff-Riley classification. Our results show that the majority of
the sources (∼88%) exhibit edge- brightened radio lobes and high
average radio power (log10[P144MHzWHz-1]=26.25), consistent with
an FR II classification. The average spectral index between 144MHz and
1.4GHz is -0.84, which is steeper than that found for previously
identified winged sources based on higher-frequency data from the Very
Large Array Faint Images of the Radio Sky at Twenty-centimeters
survey. This indicates that our study is capable of detecting fainter
sources. The median linear size of the winged sources, 498kpc,
confirms that these are large-scale structures, with approximately 16%
having sizes exceeding 0.7Mpc, making them potential candidates for
giant radio galaxies.
Description:
The Low-Frequency Array (LOFAR) is a state-of-the-art radio telescope
system designed to explore the Universe at low radio frequencies,
ranging from 10 to 240MHz. Its groundbreaking capabilities are
exemplified by the ongoing LOFAR Two-metre Sky Survey (LoTSS), which
operates in the 120-168MHz frequency range using the LOFAR High Band
Antenna (Shimwell+ 2017, J/A+A/598/A104). LoTSS aims to map the entire
northern sky at LOFAR's full 6" resolution with a sensitivity of
approximately 100uJy/beam, although sensitivity varies with decl.
The second data release (DR2) of LoTSS (LoTSS DR2;
Shimwell+ 2022, J/A+A/659/A1) expands the survey area to approximately
5700deg2, covering 13 times the area of DR1's 424deg2.
See Section 2 for further details.
Our comprehensive and detailed search for winged sources using LoTSS
DR2 has identified a total of 621 new winged radio sources and
403 candidates.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 117 621 The winged radio sources from LoTSS DR2
table3.dat 145 403 The candidates of winged radio sources from LoTSS
DR2
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See also:
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
VII/292 : DESI Legacy Imaging Surveys DR8 photometric redshifts (Duncan, 2022)
J/AJ/133/2097 : FIRST "Winged" and X-shaped radio sources (Cheung, 2007)
J/MNRAS/415/1013 : FR II radio galaxies in SDSS (Koziel-Wierzbowska+, 2011)
J/ApJS/194/31 : Morphology for groups in the FIRST database (Proctor, 2011)
J/MNRAS/430/3086 : CoNFIG AGN sample (Gendre+, 2013)
J/A+A/598/A78 : The GMRT 150MHz all-sky radio survey (Intema+, 2017)
J/MNRAS/466/4346 : Properties of extended radio galaxies (Miraghaei+, 2017)
J/A+A/598/A104 : LOFAR Two-metre Sky Survey (Shimwell+, 2017)
J/ApJS/238/9 : Giant radio sources known to date (Kuzmicz+, 2018)
J/ApJ/852/47 : "X-shaped" radio sources. I. VLA imaging (Roberts+, 2018)
J/ApJ/852/48 : "X-shaped" radio sources. II. (Saripalli+, 2018)
J/A+A/622/A1 : LOFAR Two-metre Sky Survey DR1 source cat. (Shimwell+, 2019)
J/ApJS/245/17 : X-shaped radio galaxies from FIRST (Yang+, 2019)
J/A+A/635/A5 : LoTSS giant radio galaxies. I. (Dabhade+, 2020)
J/ApJS/257/30 : BL Lac morphologies with LoTSS-DR2 144MHz (Mooney+, 2021)
J/ApJS/259/31 : Head-tail radio gal. from VLA FIRST survey (Sasmal+, 2022)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
J/A+A/680/A31 : Radio relics in LoTSS-DR2 and PSZ2 (Jones+, 2023)
J/A+A/660/A78 : LoTSS-DR2 sample overview release (Botteon+, 2022)
J/A+A/678/A151 : LoTSS DR2 optical IDs (Hardcastle+, 2023)
J/A+A/691/A287 : LoTSS DR2 restarted radio gal. in HETDEX field (Nair+, 2024)
J/A+A/696/A97 : Giant double-double radio gal. from LoTSS (Dabhade+, 2025)
J/A+A/699/A338 : LoTSS DR2 visual classifications (Horton+, 2025)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/621] Catalog running sequence number
5- 14 A10 --- Name Short name (JHHMM+DDMM)
16- 16 A1 --- f_Name [d] d = source in Proctor 2011, J/ApJS/194/31
( in Simbad)
18- 19 I2 h RAh Hour of Right Ascension (J2000) (G1)
21- 22 I2 min RAm Minute of Right Ascension (J2000)
24- 28 F5.2 s RAs Second of Right Ascension (J2000)
30- 30 A1 --- DE- [+] Sign of the Declination (J2000) (G1)
31- 32 I2 deg DEd [16/68] Degree of Declination (J2000) (G1)
34- 35 I2 arcmin DEm Arcminute of Declination (J2000)
37- 40 F4.1 arcsec DEs Arcsecond of Declination (J2000)
42- 42 A1 --- f_Pos [*] * = this is a radio position
44- 48 F5.3 --- z [0.066/1.64]? Redshift
50- 53 A4 --- zType Redshift type ("PHOT" or "SPEC") (G2)
55- 55 A1 --- r_zType [D] D = spectroscopic redshift from DESI
57- 61 F5.2 mag rmag [13.2/24.6]? Apparent r band magnitude, mr
63- 67 F5.1 mag RMag [-25.6/-19.8]? Rest-frame R band absolute
magnitude, MR
69- 74 F6.1 mJy F144 [17/5146] Integrated 144MHz flux density (G3)
76- 80 F5.3 mJy/beam IslRMS [0.05/1.22] Island RMS noise
82- 85 I4 mJy F1440 [3/1167]? Integrated 1.44GHz flux density (G3)
87- 91 F5.2 --- alpha [-1.52/-0.24]? Spectral index
between 144MHz and 1.44GHz
93- 95 I3 arcsec theta [34/584] Angular size, θ
97-100 I4 kpc Size [71/1823]? Linear size, l
102-110 F9.5 10+26W/Hz P144 [0.008/154.4]? The 144MHz power
112-114 A3 --- Wing Singed source classification (1)
116-117 A2 --- FR FR classification (II = 453 occurrences; or
I = 64 occurrences)
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Note (1): Classification as follows:
XRG = "X"-shaped radio galaxies (382 occurrences)
ZRG = "Z"-shaped radio galaxies (239 occurrences)
See Section 3.3.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/403] Catalog running sequence number
5- 14 A10 --- Name Short name (JHHMM+DDMM)
16 A1 --- f_Name [d] d = source in Proctor 2011, J/ApJS/194/31
( in Simbad)
18- 19 I2 h RAh [0/23] Hour of Right Ascension (J2000) (G1)
21- 22 I2 min RAm Minute of Right Ascension (J2000)
24- 28 F5.2 s RAs Second of Right Ascension (J2000)
30 A1 --- DE- Sign of the Declination (J2000) (G1)
31- 32 I2 deg DEd [17/68] Degree of Declination (J2000) (G1)
34- 35 I2 arcmin DEm Arcminute of Declination (J2000)
37- 40 F4.1 arcsec DEs Arcsecond of Declination (J2000)
42 A1 --- f_Pos [*] * = this is a radio position
44- 51 F8.6 --- z [0.00016/1.22]? Redshift
55- 58 A4 --- zType Redshift type ("PHOT" or "SPEC") (G2)
60 A1 --- r_zType [D] D = spectroscopic redshift from DESI
62- 65 F4.1 mag rmag [12.9/24.3]? Apparent r band magnitude, mr
67- 71 F5.1 mag RMag [-25.1/-19.8]? Rest-frame R band absolute
magnitude, MR
73- 78 F6.1 mJy F144 [16.9/8842] Integrated 144MHz flux density (G3)
80- 84 F5.3 mJy/beam IslRMS [0.04/1.6] Island RMS noise
86- 88 I3 arcsec theta [31/358] Angular size, θ
90- 93 I4 kpc Size [2/1620]? Linear size, l
95- 145 A51 --- Comm Comment (s)
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Global notes:
Note (G1): The optical host position of the sources is presented here. If no
optical host is found for a particular source, then we use radio
coordinates for the source and add a flag in f_Pos. Those radio
coordinates are given with less precision.
Note (G2): The redshift information is taken from
Hardcastle+ (2023, J/A+A/678/A151), in which the spectroscopic
redshift values are taken from the Sloan Digital Sky Survey Data
Release 16 (SDSS DR16; see V/154) and the Dark Energy Spectroscopic
Instrument (DESI: Levi+ 2013arXiv1308.0847L 2013arXiv1308.0847L). The photometric
redshifts are taken from Duncan (2020, VII/292). The PHOT redshifts
are given with less precision, up to 0.01 place.
Note (G3): Here, we use the LoTSS DR2 flux for F144. For F1400 we use the
NVSS flux, due to its better flux detection ability. The F144 values
are taken from Hardcastle+ 2023, J/A+A/678/A151, and in some cases, we
measure the flux value manually if the particular flux is not
available in the catalog.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Feb-2026