Multi-wavelength Study of Radio Galaxies in MeerKAT fields

Abstract

Active galaxies are distinct sub-types of galaxies; their centres, known as Active Galactic Nuclei (AGN), are the brightest and most persistently luminous objects in the cosmos and the AGN core is where the vast majority of radiated energy is released. When compared to the size of the host galaxy, multiple kilo-parsecs, this region is approximately 108 times smaller. The nuclei of the AGN are host to SMBHs (Supermassive Black Holes) that are 106−109M⊙, and thus light cannot travel beyond the event horizon of a black hole because of the extreme gravitational pull it generates. SMBHs’ deep gravitational potential has a considerable impact on the dynamics of their surrounding environments; approximately 10% of AGN feature large outflows and jets along their polar axes. Magnetically collimated funnels propel relativistic matter along these jets at almost the speed of light. This thesis aims to perform a multi-wavelength study of a radio galaxy using the MeerKAT radio telescope, and the 1.28 GHz radio continuum data is reduced and analysed. Because of the massive radio jets that transport vast amounts of energy deep into the intergalactic medium, MKAT J221834.96-082253.50 was selected as the source of interest for this study. The generated spectral index maps of MKAT J221834.96-082253.50 reveal a steep core region that becomes flatter when moving toward the jets. The spectrum is flatter in the inner regions of the lobes than it is towards the edges, where it is steeper. The spectral radiative age map indicates that the core of MKAT J221834.96-082253.50 is older than the jets and lobes. The one-zone leptonic self-synchrotron Compton (SSC) model was utilized to carry out a fitting of the spectral energy distribution (SED) with non-simultaneous archival multiwavelength data. The SED exhibits a double-humped shape, which can be accounted for by the synchrotron radiation of relativistic electrons in the lower energy range and the SSC process in the higher energy range.