Blazar in the constellation Draco
GB 1508+5714 is an extremely distant blazar located in the constellation of Draco. It has a redshift of (z) 4.30 and is classified as a radio-loud quasar, first discovered in 1995 by astronomers. The radio spectrum of the source appears as flat, making it a flat-spectrum source but also a bright X-ray source.
Description.
GB 1508+5714 is variable on the electromagnetic spectrum. It is known to emit a powerful gamma-ray flare in February 2022, detected by the Fermi Gamma-ray Space Telescope, between the 0.1-300 GeV range but its flux is 25 times more brighter. In additional, GB 1508+5714 also displayed optical flares that was shown on both r and i bands when shown by light curves taken from Zwicky Transient Facility. Prolonged gamma activity was detected as well, showing variable flux on timescales.
Radio imaging by Low-Frequency Array (LOFAR) on arcsecond scales, shows the source of GB 1508+5714 is mainly made up of a compact radio core with a flat spectral index of 0.02 ± 0.01 and two emission regions located both west and east directions of the core. Very long baseline interferometry (VLBI), shows the source to be a core-jet structure instead with the core located northeast and a jet component located in southwest direction, with the southernmost faint feature being identified as a radio lobe.
An X-ray jet was discovered by Chandra X-ray Observatory in 2003 with flux and luminosity values measured as 9.2 x 10−15 erg cm−2 s−1 and 1.6 x 1045 erg s−1 respectively. Based on observations, the size of the jet is found to have a projected distance of 25 kiloparsecs with the X-ray emission peaking by 2 arcseconds as it reaches southwest from the core. This emission is possibly caused due to relativistic jet particles and cosmic microwave background photons interacting with each other.