PKS 0458-020 | |
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![]() The quasar/blazar PKS 0458-020. | |
Observation data (J2000.0 epoch) | |
Constellation | Orion |
Right ascension | 05h 01m 12.809s |
Declination | −01° 59′ 14.256″ |
Redshift | 2.286000 |
Heliocentric radial velocity | 685,326 km/s |
Distance | 10.447 Gly |
Apparent magnitude (V) | 18.06 |
Apparent magnitude (B) | 19.1 |
Characteristics | |
Type | Blazar, HPQ, FRSQ |
Other designations | |
4C -02.19, PKS 0458-02, TXS 0458-020, LEDA 2818086, DA 157, OF -098, 4FGL J0501.2-0158, S3 0458-02 |
PKS 0458-020 also known as PKS 0458-02, is a quasar located in the constellation of Orion. It has a redshift of (z) 2.286 [1] [2] and was first identified as an astronomical radio source during the radio survey conducted by Parkes Observatory in 1966. [3] Subsequently the source was shown to display optical behavior [4] before being classified as a blazar via an optical polarimetry study in 1985. [5] This source also shows radio spectrum appearing to be flat, hence making it a flat-spectrum radio quasar (FRSQ). [6]
PKS 0458-020 is found variable across the electromagnetic spectrum and a source of gamma ray activity. [7] [8] [9] It is known to show optical flares which was detected by Fermi Gamma-ray Space Telescope (Fermi LAT) [10] and by the Nordic Optical Telescope in September 2012, where it was reported to be 30 times brighter than its daily flux of (E > 100 MeV) when recorded by Fermi LAT. [11] A near infrared flare was detected in January 2015. [12]
The radio structure of PKS 0458-020 is extended across a wide scale range. Radio images of the object produced via Very Large Array (VLA), showed two unique components separated by 1.8 arcseconds with a position angle of -127°. A jet can seen heading northwest before veering southwest. [1] This jet also appears to have a sharp bend by around 60° based on 15 and 43 GHz imaging. [13] [14] There is a strong compact radio core straddled by extended emission which yields a projected angular size of 3.5 arcseconds. [15] A secondary structure is located southwest from the core with a bridge-like structure almost connecting it. There is also some lobe luminosity located on the side of the counterjet with the jet's side having halo emission. [16]
The supermassive black hole in PKS 0458-020 is estimated to be 8 x 108 Mʘ based on an Ld value corresponding to the peaking of a disk spectrum with the disk luminosity being Ld ~ 2 x 1046 erg s−1. [17]
Two absorption line systems located at redshifts (z) 2.039 and (z) 2.04 were detected towards the object with the former having the largest known redshift at radio wavelengths. [18] [19]