Related papers: Modified Gravity (MOG) and Heavy Neutron Star in M…
Gravitational wave-forms from coalescences of binary black hole systems and binary neutron star systems with low tidal effects can hardly be distinguished if the two systems have similar masses. In the absence of discriminating power based…
We present interesting aspects of neutron stars (NSs) from the standpoint of a modified theory of gravity called Ho\v{r}ava-Lifshitz (HL) gravity. A deviation from general relativity (GR) in HL gravity can change typical features of the NS…
GW170817 has provided valuable constraints on the equations of state of merging binary neutron stars, which can be considered as the most probable candidate for the source of gravitational waves. On the other hand, these natural…
Direct detections of gravitational waves offer a unique opportunity to test gravity in the highly dynamical and strong field regime. Current tests are typically performed assuming signals from quasicircular binaries. However, the complex…
Coalescing binary neutron stars (NS) are expected to be an important source of gravitational waves (GW) detectable by laser interferometers. We present here a simple method for determining the compactness ratio M/R of NS based on the…
Since the 1930s, astronomical observations have accumulated evidence that our understanding of the dynamics of galaxies and groups of galaxies is grossly incomplete: assuming the validity of Newton's law of gravity on astronomical scales,…
We compare six models (including the baryonic model, two dark matter models, two modified Newtonian dynamics models and one modified gravity model) in accounting for the galaxy rotation curves. For the dark matter models, we assume NFW…
In the present work we study the gravitational effects of condensed dark matter on strange stars. We consider self-interacting dark matter particles with properties consistent with current observational constraints, and dark matter inside…
We show that the odds of the mass-gap (secondary) object in GW190814 being a neutron star (NS) improve if one allows for a stiff high-density equation of state (EoS) or a large spin. Since its mass is $\in (2.50,2.67) M_{\odot}$,…
The recent theoretical advance known as the Minimal Geometric Deformation (MGD) method has initiated a renewed interest in investigating higher curvature gravitational effects in relativistic astrophysics. In this work, we model a strange…
The combined detection of a binary neutron-star merger in both gravitational waves (GWs) and electromagnetic (EM) radiation spanning the entire spectrum -- GW170817 / AT2017gfo / GRB170817A -- marks a breakthrough in the field of…
Recent cosmological observations indicate a $5\sigma$ discrepancy between the values of the Hubble constant $H_0$ derived from late and early universe probes. A further possible tension at the $\sim 3\sigma$ level arises from different…
The properties of rotating neutron stars are investigated using eight equations of state (EOSs). We also study the relations between various observables corresponding to different angular velocities for all those EOSs. All of these EoSs…
Recent observations of ultra-dwarf galaxy NGC1052-DF2 started an interesting discussion between dark matter hypothesis and modified gravity theories. Reported low velocity dispersion (< 10.5 km/s at 90% confidence level) derived from the…
Observations of the high-frequency gravitational waves (GWs) emitted by the hot and massive remnant of a binary neutron star merger will provide new probes of the dense-matter equation of state (EoS). We show that current uncertainties in…
The direct detection of gravitational waves by the LIGO-Virgo collaboration has opened a new window with which to measure cosmological parameters such as the Hubble constant $H_0$, and also probe general relativity on large scales. In this…
We search for features in the mass distribution of detected compact binary coalescences which signify the transition between neutron stars and black holes. We analyze all gravitational wave detections by LIGO-Virgo-KAGRA made through the…
Neutron stars and their mergers provide the highest-density regime in which Einstein's equations in full (with a matter source) can be tested against modified theories of gravity. But doing so requires a priori knowledge of the Equation of…
Gravitational lensing in a modified gravity (MOG) is derived and shown to describe lensing without postulating dark matter. The recent data for merging clusters identified with the interacting cluster 1E0657-56 is shown to be consistent…
Besides their astrophysical interest, compact stars also provide an arena for understanding the properties of theories of gravity that differ from Einstein's general relativity. Numerous studies have shown that different modified theories…