Black hole (BH) accretions are very powerful sources of energy in the universe. In accretion phenomena, the surrounding gas spirals down towards the central BH and forms a disc or quasi-spherical structure based on the ...

Evolution of galaxies is a phenomenon that affects the formation and composition of galaxies, and the intergalactic medium. It is mediated by processes that establish a symbiotic relationship between a galaxy and the ...

The advent of dedicated surveys for studying transient events has invoked a great interest in the study of supernovae (SNe). The rate of discovery of SNe has hence gone up ten-fold relinquishing their diversity. SNe not ...

In this thesis we have introduced a real space morphological tool, Contour Minkowski tensor (CMT) to analyse the 21cm brightness temperature field from EoR. We showed that the size and shape information of structures ...

Massive stars are energetic sources of radiation and stellar wind. They are mostly born together in dense cold clouds in the interstellar medium (ISM). Regions in the ISM that are densely populated by stars are known as ...

The epoch of Cosmic Dawn and Reionization is one of the most important time periods of the universe when first sources of radiation like stars and galaxies were formed, and they changed the properties of their surrounding ...

In this thesis we have studied bar formation and evolution using N-body simulations. We have focused on the effect of bulge mass and concentration on bar formation and evolution, and derived a new bar formation criterion. ...

A system of two stars in which one is a black hole (BH) is referred to as a black hole binary (BHB). In a BHB, it is possible to have mass transfer from the secondary star (companion star) to the primary black hole. ...

In this thesis, we study two different aspects of accretion flows- (i) quasi-periodic oscillations (QPOs) seen in the light curves of X-ray binaries as a possible consequence of shock oscillations, (ii) global 3D ideal ...

We study the spectro-temporal properties of the black hole X-ray binaries (BHXBs) GRS 1915+105 and IGR J17091-3624 with data from RXTE, Chandra and XMM-Newton. From the analysis result, we propose models of accretion ...