MRG: The Miscellaneous Radio Galaxies from the FIRST Survey

Abstract

Miscellaneous Radio Galaxies (MRGs) are very rare kind of radio galaxies that exhibit unusual and different jet alignment and orientation from a typical radio galaxy. The peculiar and unique morphology of this type of radio source makes them a special case of study. In this paper, we report the identification of fifteen MRGs from VLA Faint Images of the Radio Sky at Twenty-Centimeters (VLA FIRST) Survey. The MRGs are identified manually by visual inspection of the FIRST database (December, 2017). The individual radio morphology of each sources are cross-checked at different frequencies from other surveys like TIFR GMRT Sky Survey at 150 MHz and Westerbork Northern Sky Survey at 325 MHz. We also identify the associated optical counterparts from the Sloan Digital Sky Survey (SDSS), where available. The different physical parameters like spectral index and radio luminosity of these MRGs are also estimated. An overview on the origin of these unique sources are also drawn.

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).…”

“…Based on radio morphology, we searched for radio sources that have unique and peculiar morphologies. The morphology of these sources is different from all known structures like “wings,” DDRGs, or BT radio sources; that is why they are unique and known as Miscellaneous Radio Galaxies (MRGs) (Bera et al 2022a; Schoenmakers et al 2000). Bera et al (2022a) reported such 15 miscellaneous radio sources from VLA Faint Images of the Radio Sky at Twenty‐Centimeters (VLA FIRST) Survey at 1.4 GHz.…”

“…The morphology of these sources is different from all known structures like “wings,” DDRGs, or BT radio sources; that is why they are unique and known as Miscellaneous Radio Galaxies (MRGs) (Bera et al 2022a; Schoenmakers et al 2000). Bera et al (2022a) reported such 15 miscellaneous radio sources from VLA Faint Images of the Radio Sky at Twenty‐Centimeters (VLA FIRST) Survey at 1.4 GHz. They presented a detailed study on the morphological structure of the MRG sources and also studied other properties of these sources.…”