“Winged” Radio Sources from the LOFAR Two-meter Sky Survey First Data Release (LoTSS DR1)

Abstract

A small number of extragalactic radio sources disclose a pair of low-surface-brightness radio lobes, known as “wings,” aligned at a certain angle to the primary jets. Such exotic sources are known as “winged” radio sources. Here we report the new identification of a total of 26 “winged” radio sources from the LOFAR Two-meter Sky Survey First Data Release (LoTSS DR1). Out of the 26 “winged” sources, 14 are identified as X-shaped radio galaxies and the remaining 12 as Z-shaped radio galaxies. The available optical counterpart of each radio galaxy is cataloged along with its estimated redshift. Among the 26 sources, 15 candidates are classified as FR-II radio galaxies, and two are classified as FR-I type. For nine candidates, no conclusions are drawn due to their complex morphology. We also calculate the physical parameters such as spectral index, radio luminosity, and power of the sources. We have made a statistical study of the spectral index by combining our estimated value with the spectral index collected from previous works. A mean value of spectral index of 0.71 is obtained.

Characteristics of remnant radio galaxies detected in the deep radio continuum observations from the SKA pathfinders

“…Interestingly, the northern component which resembles with a backflow tail in the 400 MHz uGMRT image clearly shows two peaks in the 1.5 GHz JVLA image (see Figure 2, middle left panel). Thus, we find that both northern and southern components have two-peak emission, which is commonly seen in the winged radio galaxies classified as the Z-shaped and X-shaped radio sources, wherein diagonally opposite bright peaks correspond to primary lobes, and fainter peaks correspond to secondary lobes, possibly from the previous episode of AGN jet activity (Lal et al, 2019;Bera et al, 2022). We note that the discovery of wing-shaped radio morphology in GMRT022338-045418 is credited to the sensitivity and resolution of band-3 uGMRT observations that are adequate to detect faint diffuse radio emissions.…”

Miscellaneous radio galaxies from LOFAR survey

“…Most of the radio sources with irregular radio morphology are classified into some classes and sub‐classes. For example, “winged” radio galaxy (Bera et al 2020, 2022a, 2022b; Cheung 2007; Leahy & Parma 1992; Yang et al 2019) an exotic subclass, that exhibits two, low‐surface‐brightness radio lobes oriented at an angle to the active or high‐surface‐brightness lobes, giving the radio galaxy an overall “X” or “Z” shape. When the pair of an extra lobe aligned along the same axis, as the primary lobe axis with a coinciding radio core, the class of radio galaxies is known as “double‐double” radio galaxies (DDRGs) (Saikia et al 2006; Schoenmakers et al 2000).…”