Astronomy and Astrophysics Programme (AAP)
Recent Submissions
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Observational study of decayless waves across different scales in the solar corona
The long-standing problem of coronal heating focuses on probing sources that can continuously supply energy to sustain million-degree temperatures. Magnetohydrodynamic (MHD) waves play a crucial role because their dissipation ... -
Insights into the genesis and dynamics of the solar spicule forest: aided by simulations and laboratory experiments
The solar atmosphere is embedded with an enormous no of plasma structures with a vast range of spatial and temporal scales. Solar spicules are one of such ubiquitous features of the sun, which are present in millions ... -
Unravelling the kinematics, dynamics and structure of galaxies using H I - 21cm observation
The advent of the multi-wavelength observations of galaxies in this recent era gives us the opportunity to study the details of the different pivotal facets of galactic astrophysics. Among the observations in different ... -
A study of the evolution of the bulges and disks of spiral galaxies in interacting and isolated environments
Galaxies are usually found in groups and clusters where they interact with each other gravitationally. These interactions affect the internal dynamics of the galaxies. In this thesis, we have studied the effect of flyby ... -
A Study of the X-ray Variability and Accretion Mechanism in High Mass X-ray Binary Pulsars
High-mass X-ray binaries are among the most luminous X-ray sources. They host an accreting compact object (more often a neutron star) and a massive (M > 10 M⊙) donor star. They are among the earliest discovered X-ray sources ... -
Panchromatic study of star clusters: binaries, blue lurkers, blue stragglers and membership
Binary systems can evolve into immensely different exotic systems such as blue straggle stars (BSSs), yellow straggler stars, cataclysmic variables, type Ia supernovae depending on their initial mass, the orbital ... -
Understanding the vertical structure of galactic stellar disc and the role of interstellar gas and dark matter halo
The aim of this thesis is to understand the dynamical effect of interstellar gas and dark matter halo on the vertical distribution of stars in our Galaxy as well as modeling the stellar distribution in a generalized and ... -
The multiphase interstellar medium: A study of various physical and kinematical properties
Interstellar medium (ISM) is the relatively empty space in between the stars. It has different phases, like, neutral, molecular, and ionized. Neutral interstellar medium, which is pervaded all over the galaxy, is sometimes ... -
Observational Constraints on Global 21-cm Signal from the Epoch of Reionization
One of the most promising probes of Cosmic Dawn (CD) and Epoch of Reionization (EoR) is the rest-frame global 21-cm signal of neutral hydrogen (HI) produced by the intergalactic medium (IGM) prior to the end of the EoR ... -
Magnetically arrested advective accretion flows around black holes and their implications to ultraluminous X-ray sources and blazars
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 ... -
Nonlinear and Geometric Properties of Accreting Compact Sources Based on Spectral and Timing Analyses
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 ... -
The Formation and Evolution of Bars, and Its Impact on Galaxy Dynamics
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. ... -
Analytical Formalism to Study the 21 cm Signal from Cosmic Dawn and Epoch of Reionization
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 ... -
Thermal and Non-thermal Processes in Young Star clusters
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 ... -
Spectro-temporal signatures of accretion flows around Galactic Black Holes
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. ... -
Numerical studies of shock oscillations and MRI turbulence in accretion
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 ... -
Morphology and topology of cosmological fields during the Epoch of Reionization
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 ... -
Observational study of Core-Collapse Supernovae
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 ... -
Understanding Multi-Wavelength Signatures of Galactic Outflows Through 3-D Simulations
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 ...
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