Browsing Division of Physical and Mathematical Sciences by Subject "Research Subject Categories::NATURAL SCIENCES::Physics::Astronomy and astrophysics"
Now showing items 1-14 of 14
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Heavy flavour and direct photon probes of the gluon Sivers function
Traditionally the production of heavy quarkonia, heavy-flavour mesons as well as of direct photons, has been used to constrain the gluon density inside the proton. In this thesis, I have assessed various heavy flavour ... -
Hydrodynamic and hydromagnetic instabilities leading to turbulence in astrophysical accretion disks and their connection to laboratory shear flows
Accretion disks are astrophysical objects formed around a denser object, mainly in the form of a disk. In an accretion disk, matter spirals in and falls onto the central object. To match the observations, the underlying ... -
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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
Probing the inflationary universe and reheating with primordial black holes and induced gravitational wave background
The direct observational test for the earliest phase of our universe comes from cosmic microwave background (CMB) radiation, which can only probe up to the recombination era. The only definitive event during the pre-recombination ... -
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. ... -
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 ... -
Unraveling certain high energy astrophysical features based on advective accretion disks
The presence of an accretion disk around a neutron star (NS) or a black hole (BH) is mainly responsible for the observed X-rays from the night sky. NS or BH is a part of the binary systems, and matter flows from a companion ... -
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 ...