White dwarf mass-radius relation in theories beyond general relativity
White-dwarf mass-radius relation in Scalar-Tensor-Vector Gravity and beyond Horndeski theories of G3 type.
Publications: arXiv.2301.08677;
Tousif Islam (তৌসিফ ইসলাম)
Modified Gravity Theories
Beyond General Relativity
My secondary direction of research constitutes the exploration of beyond GR theories.
The validity of GR is well-established in solar-system neighborhood and binary pulsar systems. The detection of gravitational waves from the mergers of binary black holes (BBHs) has further allowed us to test GR in the previously unexplored highly relativistic strong field regime of gravity. So far all GW observations are consistent with GR. However, GR is plagued by an observed 'mass-discrepancy' in galaxies and clusters. One way to reconcile GR with observations is to invoke exotic dark matters. No-show of dark matter particles in ambitious experiments so far though has encouraged researchers to look for alternative explanation which considers the 'mass-discrepancy' as a signature of the breakdown of GR at galactic and cosmological scales.
Many alternative or modified gravity theories try to achieve these through replacing Einstein's GR with new laws of gravity. My research explores the ability of motivated alternative gravity theories (Weyl Conformal gravity, Chern-Simons gravity, f(R) gravity, Scalar-Tensor-Vector gravity) in providing acceptable fits to the dynamics of self gravitating objects of a wide range of masses, namely globular clusters, galaxies and clusters of galaxies.
Image: arXiv:1807.09241 (Ezquiaga & Zumalacarregui 2018)
NGC1052-DF2 and the fate of modified gravity
Modified Gravity Theoriesin Light of the Anomalous Velocity Dispersion of NGC1052-DF2.
Publications: arXiv.1908.07160;
Ultre-diffuse galaxies
Enigmatic Velocity Dispersions of Ultra-Diffuse Galaxiesin Light of Modified Gravity Theories and Radial Acceleration Relation.
Publications: arXiv.1910.09726;
Milky Way as a testing bed for gravity
Acceleration Relations in the Milky Way as Differentiators of Modified Gravity Theories.
Publications: arXiv.1911.11836;
Globular Clusters as a probe for gravity
Globular clusters as a probe for Weyl Conformal Gravity.
Publications: arXiv.1811.00065;
Viability of conformal gravity
Testing Weyl Gravity at Galactic and Extra-galactic Scales.
Publications: arXiv.1808.06923;