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Active galactic nuclei (AGN) are powered by accretion disks onto supermassive black holes in the the centers of galaxies. AGN are believed to play important roles in the evolution of both supermassive black holes and their host galaxies…
Accreting neutron stars can power a wide range of astrophysical phenomena including short- and long-duration gamma-ray bursts, ultra-luminous X-ray sources, and X-ray binaries. Numerical simulations are a valuable tool for studying the…
KHARMA (an acronym for "Kokkos-based High-Accuracy Relativistic Magnetohydrodynamics with Adaptive mesh refinement") is a new open-source code for conducting general-relativistic magnetohydrodynamic simulations in stationary spacetimes,…
In general relativistic magneto-hydrodynamic (GRMHD) simulations, accreted magnetic flux on the black hole horizon episodically decays, during which magnetic reconnection heats up the plasma near the horizon, potentially powering…
The code HARM\_COOL, a conservative scheme for relativistic magnetohydrodynamics, is being developed in our group and works with a tabulated equation of state of dense matter. This EOS can be chosen and used during dynamical simulation,…
The almost simultaneous detection of GRB170817A and GW170817 ushered in nearly a decade of interest in binary neutron star mergers and their multi-messenger signals, resulting in a greater understanding of the processes that produce…
We incorporate realistic, tabulated equations of state into fully relativistic simulations of magnetized neutron stars along with a neutrino leakage scheme which accounts for cooling via neutrino emission. Both these improvements utilize…
I have developed two numerical codes to investigate the dynamics of collapsars. One is two-dimensional MHD code that are performed using the Newtonian (ZEUS-2D) code where realistic equation of state, neutrino cooling and heating processes…
(Abridged) In this paper we present a compilation of results from our most advanced neutron star merger simulations, including a description of the employed numerical procedures and a more complete overview over a large number of computed…
This paper presents the benchmarking and scaling studies of a GPU accelerated three dimensional compressible magnetohydrodynamic code. The code is developed keeping an eye to explain the large and intermediate scale magnetic field…
We describe the implementation of a module for the Athena magnetohydrodynamics (MHD) code which solves the time-independent, multi-frequency radiative transfer (RT) equation on multidimensional Cartesian simulation domains, including…
The Fully Constrained Formulation (FCF) of General Relativity is a novel framework introduced as an alternative to the hyperbolic formulations traditionally used in numerical relativity. The FCF equations form a hybrid elliptic-hyperbolic…
We study the evolution in axisymmetry of accretion disks formed self-consistently through collapse of magnetized hypermassive neutron stars to black holes. Such stars can arise following the merger of binary neutron stars. They are…
Graph Neural Networks (GNNs) are emerging as a formidable tool for processing non-euclidean data across various domains, ranging from social network analysis to bioinformatics. Despite their effectiveness, their adoption has not been…
Long-term neutrino-radiation resistive-magnetohydrodynamics simulations in full general relativity are performed for a system composed of a massive neutron star and a torus formed as a remnant of binary neutron star mergers. The simulation…
The construction of high-resolution shock-capturing schemes is vital in producing highly accurate gravitational waveforms from neutron star binaries. The entropy based flux limiting (EFL) scheme is able to perform fast converging binary…
We introduce a new hybridized discontinuous Galerkin method for the incompressible magnetohydrodynamics equations. If particular velocity, pressure, magnetic field, and magnetic pressure spaces are employed for both element and trace…
We present an improved version of the ECHO-QGP numerical code, which self-consistently includes for the first time the effects of electromagnetic fields within the framework of relativistic magnetohydrodynamics (RMHD). We discuss results of…
We propose a simple ansatz for estimating the value of the numerical resistivity and the numerical viscosity of any Eulerian MHD code. We test this ansatz with the help of simulations of the propagation of (magneto)sonic waves, Alfven…
Conventional AC Power Flow (ACPF) solvers like Newton-Raphson (NR) face significant computational and convergence challenges in modern, large-scale power systems. This paper proposes a novel, two-stage hybrid method that integrates a…