Galaxy clusters, the largest gravitationally bound structures in the Universe, provide a unique laboratory for
studying various astrophysical processes. This study focuses on diffuse radio emission associated with low-mass
Atacama Cosmology Telescope galaxy clusters observed using the MeerKAT telescope within the MeerKAT
Galaxy Cluster Legacy Survey (MGCLS). Our investigation aims to...
We present a comprehensive phase-resolved photometric, spectroscopic, and polarimetric analysis of the intermediate polar (IP) 1RXS J080114.6–462324, based on multi-instrument observations. These include data from the HIgh-speed Photo-POlarimeter (HIPPO), the Southern African Large Telescope (SALT), and the SAAO 1.0-m and 1.9-m telescopes, complemented by archival photometry from the...
‘Spider’ binary systems – black widow and redback binaries consisting of a millisecond pulsar and a low-mass companion in a compact orbit, are important types of pulsar system exhibiting various key features, including radio eclipses, optical light curves from the heated companion, and X-ray and GeV orbital light curves and spectra. In these systems, the intense pulsar wind heats and may...
Gamma-ray binaries are a rare class of high-mass binary systems where the peak of their spectral energy distribution occurs in the gamma-ray energy range. These systems have proven to be excellent laboratories for studying particle acceleration mechanisms. One such system is LMC P3, the most luminous gamma-ray binary discovered to date and, so far, the only one found outside the Milky Way. It...
We report the detection of a Low Synchrotron Peaked (LSP) blazar PKS 0346-27 at redshift 0.99 by the High Energy Stereoscopic System (H.E.S.S.) on 3rd November, 2021 with a significance above 5σ. The spectral energy distribution (SED) consists of the simultaneous observations by Fermi-LAT, Swift XRT/UVOT and ATOM during the H.E.S.S detection period while the multiwavelength light curve...
The spectral width (W) is proposed as a new measure to address the complexities in the GRB prompt phase spectral studies. We carried out a detailed procedure to redefine the Band function with W as one of the parameters, to study the GRB spectra. This model was convolved with the XSPEC, and the temporal evolution of W, for the case of GRB 220426A and GRB 230812B using the Fermi/ GBM data, was...
Dwarf novae (DNe) are a subclass of Cataclysmic Variable Stars, which are a type of binary system that contain a white dwarf (WD) primary star and a main-sequence secondary star (typically a K- or an M-type star) where the secondary star transfers matter onto the WD via Roche-lobe overflow. These binary systems often have an accretion disk. DNe have outbursts, which are 2-6 magnitude increases...
Blazars, a subclass of active galactic nuclei with collimated jets of matter oriented at the observer, Earth. These jets produce radiation across the entire electromagnetic spectrum, in the form of two broad, non-thermal peaks. There are competing models capable of reproducing this radiation, which can be broadly categorised into two types: leptonic and lepto-hadronic, based on the exclusion...
Namibia stands out as an exceptional location for astronomical research, offering pristine night skies and ideal observation conditions. Home to Africa's first International Dark Sky Reserve, the country boasts an arid climate with minimal rainfall, resulting in abundant cloudless nights perfect for extended viewing hours. This environment is ideal for facilities like the High Energy...
Blazars make up the largest fraction of Fermi-LAT-detected sources of high-energy gamma-ray emission. At the same time, their emission is known to be highly variable throughout the electromagnetic spectrum. With hints of their highest fractional variability in the radio regime being present at the highest radio frequencies, monitoring blazars at mm-wavelengths shall be one of the key science...
Gamma-ray binaries are high-mass binary systems that emit predominantly in the high-energy and very-high-energy gamma-ray regimes. LMC P3 is the only known gamma-ray binary located outside our galaxy and consists of an O5,III companion star and a compact object with a mass in the range of a neutron star or a black hole. The leading theory is that all gamma-ray binaries contain a young,...
We present phase-resolved analysis of the polar QS Telescopii using photometry, spectroscopy, Doppler tomography, photopolarimetry, and circular spectropolarimetry collected between 2017 and 2025. We report the first detection of quasi-periodic oscillations (QPOs) in QS Tel, with timescales of 6–10 minutes, revealing dynamic accretion behavior. Doppler tomography of Hα and HeII (4686 Å) lines...
