Extended Catalog of Winged or X-shaped Radio Sources from the FIRST Survey
Artikel i vetenskaplig tidskrift, 2019

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 150 MHz, 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 ? flatter than ?0.3) between 150 MHz and 1.4 GHz, or between 1.4 and 5 GHz. 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.


Radio continuum emission

Active galactic nuclei





Xiaolong Yang

Beijing University of Technology

Ravi Joshi

Beijing University of Technology


University of Mumbai

Aryabhatta Research Institute of Observational Sciences

Tao An

Chinese Academy of Sciences

Luis C. Ho

Beijing University of Technology

Paul J. Wiita

The College of New Jersey

Xiang Liu

Chinese Academy of Sciences

Jun Yang

Chinese Academy of Sciences

Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium

Ran Wang

Beijing University of Technology

Xue-Bing Wu

Beijing University of Technology

Xiaofeng Yang

Chinese Academy of Sciences

Astrophysical Journal, Supplement Series

0067-0049 (ISSN) 1538-4365 (eISSN)

Vol. 245 1 17


Medicinsk laboratorie- och mätteknik

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik


Onsala rymdobservatorium



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