4C +28.07 is found variable on the electromagnetic spectrum. It is known to show intense gamma ray activity observed by Fermi Large Area Telescope on October 3, 2011.[7] In additional to gamma ray activity, 4C +28.07 also shows near-infrared flares.[8][9][10] Between 16 January 2013 and 13 March 2020, four strong gamma ray flares were observed by Fermi LAT, during the Interferometric Monitoring of Gamma-ray Bright Active Galactic Nuclei (iMOGABA) program.[11]
A bright and rapid flare was detected in 4C +28.07 in October 2018. The flare lasted 30 minutes and its gamma ray flux reached a maximum peak of 6.7 ± 0.81 x 10−6photon cm−2 s−1. This flux is 31 times higher than the average flux. Furthermore, its spectrum, extended upwards to 316 GeV before hardening beyond 60 GeV.[5]
Multiepoch Very Long Baseline Array (VLBA) radio imaging at 22 GHz, 4C +28.07 shows a radio core and a prominent jet projecting northwards out by 3.5 mas from it, modelled by three main stationary components with one of them showing a complex structure both along it and in transverse direction.[12] There is presence of extended emission[13] and a diffused secondary component.[14]
According to radio band observations by Very Long Baseline Interferometry (VLBI), the jet of 4C +28.07 is described having a one-sided structure on parsec scales. It has a jet speed of (10.11 ± 0.39)c implying superluminal motion[5] and is suggested of a "kink" observed in 3C 273 with the jet jumping sideways and resuming its original position.[15] When observed by Chandra X-ray observatory, the jet shows a sharp bend at a -90° position angle which subsequently terminates at a bright component within 3 mas.[16]
The supermassive black hole in 4C +28.07 is estimated to be 1.65+1.66-0.82 x 109 Mʘ based on an optical spectroscopy conducted on flat-spectrum radio quasars.[5][17]
