TXS 1433+205: The most distant gamma-ray emitting FR II radio galaxy. Issue 1 (23rd December 2022)

• Record Type: Journal Article
• Authors: Paliya, Vaidehi S; Saikia, D J; Stalin, C S
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 520:Issue 1(2023)
• Page Start: L33
• Page End: L37
• Publication Date: 2022-12-23
• Subjects: BL Lacertae objects: general -- galaxies: jets -- gamma-rays: galaxies; Astronomy -- Research -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnrasl/slac165
• Languages: English
• ISSNs: 1745-3933

Abstract

ABSTRACT: The orientation of the jet axis to the line of sight of the observer plays a major role in explaining the phenomena observed from blazars and radio galaxies. In the γ-ray band, only a handful of radio galaxies have been identified, all being located in the nearby Universe ( z < 0.5). Here, we report the identification of 4FGL J1435.5+2021, associated with TXS 1433+205, as a Fanaroff–Riley type II (FR II) radio galaxy at a considerably higher redshift of z = 0.748, thereby making it the most distant γ-ray detected radio galaxy known as of now. The Very Large Array Sky Survey data at 3 GHz resolves the source morphology into a bright core, a jet and two hotspots, with a total end-to-end projected length between lobe extremities of ∼170 kpc. The optical and radio properties of this enigmatic object suggest it to be a high-excitation FR II radio galaxy. The multiwavelength behaviour of TXS 1433+205 is found to be similar to other γ-ray detected FR II sources but is at the high-luminosity end. We suggest that the ongoing and upcoming high-resolution radio surveys will lead to the identification of many more high-redshift radio galaxies in the γ-ray sky, thus allowing comprehensive studies of misaligned relativistic jets.