The recent detection of the gamma-ray burst GRB 221009A has garnered significant attention due to its unprecedented brightness and the first-ever detection of very-high energy (VHE, > 10 TeV) gamma rays from a GRB at the redshift of z=0.151. This redshift indicates a distance at which the gamma-ray flux at these energies would typically undergo severe attenuation due to gamma-gamma pair...
The unified model of jetted active galactic nuclei (AGNs) based on intrinsic properties presumes that the blazar subtypes of BL Lacertae objects (BLs) and flat-spectrum radio quasars (FSRQs) are aligned equivalents of Fanaroff–Riley type I (FR I) and Fanaroff–Riley type II (FR II) radio galaxies from where their parent sources are obtained. Using compiled radio, X-ray and γ-ray data of 397...
I present the results of my Master's project to comprehensively search for high-redshift radio galaxies (HzRGs) within 37 fields of the MeerKAT Galaxy Cluster Legacy Survey's first data release. These fields are distinguished by their good dynamic range and comprehensive optical and infrared coverage through the Dark Energy Camera Legacy Survey and the All-sky Wide Infrared Survey Explorer....
Observations of galaxy clusters at low radio frequencies serve as a valuable tool for studying the non-thermal intracluster medium (ICM). Diffuse radio emissions, such as radio halos and relics, assist in probing a cluster’s non-thermal physics and magnetic fields. However, radio observations lack redshift information, rendering it challenging to determine the origin of extended radio...
Galaxies exhibit a wide variety of observable properties. The environment in which a galaxy resides is known to significantly impact its characteristics. A galaxy's cold gas component (usually a disk for late-type systems) is particularly sensitive to environmental conditions. Neutral atomic hydrogen (HI) as we know it, makes up the large majority of a galaxy's gas content.
Galaxies are...
We present an investigation of the properties of radio relics (RRs), one type of diffuse emission located at the outskirts of some Galaxy Clusters (GCs), and a search for information about the origin of non-thermal processes taking place in the cluster atmospheres. We adopt a new approach to constrain models for the origin of RRs according to the following steps: i) Instead of working on a...
The chemical abundance of active galaxies, which host active galactic nuclei (AGN) at their centre, remains poorly studied, most often due to the difficulty of removing the effect of AGN in metallicity measurements. In particular, the chemical abundance of active galaxies in different environments, including clusters and groups of galaxies, is still unknown. In this work, we use a novel HCm...
The MeerKAT Exploration of Relics, Giant Halos, and Extragalactic Radio Sources (MERGHERS) survey is targeting a homogeneously selected sample of SZ-detected galaxy clusters with the aim of probing the cosmic and mass evolution of diffuse cluster radio emission. Almost all statistical cluster samples studied for diffuse radio emission are restricted to low-redshift, high-mass clusters due to...
cores, provides valuable insights into supermassive black holes, galaxy evolution, and cosmic environments. The Africa Millimetre Telescope (AMT) that will be constructed in the Khomas Highlands in Namibia will be designed to add to the Event Horizon Telescope (EHT) network. With the AMT, the EHT will be able to produce colour movies of black holes, allowing us to better determine their...
We present the second data release of the MeerKAT Absorption Line Survey (MALS), consisting of wideband continuum catalogues of 391 pointings observed by MALS at L band. The full wideband catalogue covers 4344 deg$^2$ of sky with a depth down to $10\ \mu \mathrm{Jy\ beam}^{-1}$, and contains 971,980 sources. With its balance between survey depth and sky coverage, MALS DR2 covers five orders of...
From observations, we see non-thermal radio emission with emissivity ranging from 1 to 3, extended over a large region (∼ megaparsec) in galaxy clusters, which contain largely collisionless plasma. To explain this, the electrons should be energized or accelerated. One explanation is that the energy released during a merger event could be channeled to accelerate electrons through turbulence or...
Studying the radio spectral energy distribution (SED) of distant galaxies is essential for understanding their assembly and evolution over cosmic time. We present rest-frame mid-radio ($\simeq 1-16$\, GHz) SEDs of a sample of starburst galaxies at 1.5 < z < 4.5 in the COSMOS field as part of the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) project. MeerKAT...
