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.
