146 citations · 286 across the 21 of their papers we have counts for
22 papers
Dynamics and geometry of the inner sub-parsec-scale jet in 3C 279 observed with the Event Horizon Telescope
Hendrik Mueller, Sebastiano D. von Fellenberg, Ai-Ling Zeng +275
The 2021 Event Horizon Telescope observations resolve the innermost jet region of the blazar 3C279 with unprecedented detail. The reconstructed images consistently reveal a compact…
From Morphology to Variability: Radiative Cooling Effects on Horizon-Scale Polarization in Two-Temperature GRMHD Simulations
Jane SiNan Long, Akhil Uniyal, Mingyuan Zhang +4
Polarization signatures provide a new window to investigate the effects of radiative cooling in the horizon-scale accretion flows. Morphology and variability of polarization offer…
Identifying highly magnetized white dwarfs: A dimensionality reduction framework for estimating magnetic fields
Surajit Kalita, Akhil Uniyal, Tomasz Bulik +1
Magnetic fields play a crucial role in compact object physics, particularly in white dwarfs (WDs), where high densities can sustain strong magnetic fields. Observations have reveal…
High-Order Photon Rings around Kerr Naked Singularities
Hina Suzuki, Yosuke Mizuno, Akhil Uniyal +3
We present a detailed study of higher-order photon rings of an accreting Kerr naked singularity (KNS) with dimensionless spin parameter ; i.e., a horizonless, overly spinni…
The future ability to test theories of gravity with black-hole shadows
Akhil Uniyal, Indu K. Dihingia, Yosuke Mizuno +1
The horizon-scale images of supermassive black holes (BHs) by the Event Horizon Telescope Collaboration (EHT) have provided new opportunities to test general relativity and other t…
GRMHD Study of Accretion onto time-like Naked Singularities
Akhil Uniyal, Indu K. Dihingia, Yosuke Mizuno +1
Naked singularities (NkS) are solutions to the Einstein field equations that violate the cosmic censorship conjecture. Recent studies indicate that these objects may serve as compe…
Refining fundamental constants with white dwarfs: machine learning informed constraints on fine-structure constant and proton-to-electron mass ratio
Akhil Uniyal, Surajit Kalita, Yosuke Mizuno +2
We explore the potential variation of two fundamental constants, the fine-structure constant and the proton-to-electron mass ratio , within the framework of modified gravity…
Imprints of Different Types of Low-Angular-Momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations
Indu K. Dihingia, Akhil Uniyal, Yosuke Mizuno
Depending on the astrophysical source and its environment, the accretion flows can exhibit a variety of behaviors and characteristics in accordance with the type of solutions. We s…
The Fate of Transonic Shocks around Black Holes and their Future Astrophysical Implications
Indu K. Dihingia, Akhil Uniyal, Yosuke Mizuno
Theoretical models have long predicted the existence of shocks in multi-transonic accretion flows onto a black hole, yet their fate under realistic general relativistic simulations…
Revealing Limitation in the Standard Cosmological Model: A Redshift-Dependent Hubble Constant from Fast Radio Bursts
Surajit Kalita, Akhil Uniyal, Tomasz Bulik +1
A major issue in contemporary cosmology is the persistent discrepancy, known as the Hubble tension, between the Hubble constant () estimates from local measurements and those…
Black hole accretion and radiation variability in GRMHD simulations with Rezzolla-Zhidenko spacetime
Kotaro Moriyama, Alejandro Cruz-Osorio, Yosuke Mizuno +2
The Event Horizon Telescope (EHT) has revealed the horizon-scale radiation of Sagittarius A* (Sgr A*), our galaxy's central supermassive black hole, offering a new platform to test…
Distinguishability of a naked singularity from a black hole in dynamics and radiative signatures
Indu K. Dihingia, Akhil Uniyal, Yosuke Mizuno
Can a naked singularity (NkS) be distinguished from a black hole (BH)? We have investigated it with cutting-edge general relativistic magneto-hydrodynamic (GRMHD) simulations, foll…
Revisited equilibrium solution of Fishbone and Moncrief torus for extended GRMHD simulations
Akhil Uniyal, Indu K. Dihingia, Yosuke Mizuno
Accretion physics has become more important recently due to the detection of the first horizon-scale images of the super-massive black holes of M\,87 and Sgr~A by the Event…
Observational signatures of Rotating compact objects in Plasma space-time
Saurabh Kumar, Akhil Uniyal, Sayan Chakrabarti
We have investigated the characteristics of shadows cast by the Kerr black hole in the presence of plasma and compared them to those of a rotating wormhole in a uniform plasma spac…
Effect of temperature on measurement of fundamental constants using white dwarfs in Gaia-EDR3 survey
Akhil Uniyal, Surajit Kalita, Sayan Chakrabarti
Fundamental constants are crucial for comprehending physical mechanisms, but their measurements contain uncertainties due to experimental limitations. We investigate the impact of…
Observational Signatures: Shadow cast by the effective metric of photons for black holes with rational non-linear electrodynamics
Akhil Uniyal, Sayan Chakrabarti, Mohsen Fathi +1
This study explores spherically symmetric non-linear electrodynamics black holes and their effects on light propagation. We derive the governing metric, revealing radial coordinate…
Shadow and Weak Gravitational lensing of rotating traversable Wormhole in Non-homogeneous Plasma Space-time
Saurabh Kumar, Akhil Uniyal, Sayan Chakrabarti
In this work, we have studied the behavior of null geodesics within a rotating wormhole space-time in non-magnetized pressure-less plasma. By focusing on the dispersion relation of…
Study of relativistic accretion flow in the theory of gravity
Akhil Uniyal, Sayan Chakrabarti, Santabrata Das
We present the properties of relativistic, inviscid, low angular momentum, advective accretion flow in a gravity theory that satisfactorily mimics the asymptotically flat va…
Nonlinearly charged black holes: Shadow and Thin-accretion disk
Akhil Uniyal, Sayan Chakrabarti, Reggie C. Pantig +1
In this paper, we explore the effect of non-linear electrodynamics (NLED) parameters and magnetic charges on various aspects of black holes, like how they bend light, how they emit…
Constraining fundamental parameters in modified gravity using Gaia-DR2 massive white dwarf observation
Surajit Kalita, Akhil Uniyal
Various experiments and observations have led researchers to suggest different bounds on fundamental constants like the fine-structure constant and the proton-to-electron mass rati…
Some Observable Physical Properties of the Higher Dimensional dS/AdS Black Holes in Einstein-Bumblebee Gravity Theory
Akhil Uniyal, Sara Kanzi, İzzet Sakallı
We study the greybody factors, quasinormal modes, and shadow of the higher dimensional de-Sitter (dS)/ anti de-Sitter (AdS) black hole spacetimes derived from the Einstein-bumblebe…
Probing a nonlinear electrodynamics black hole with thin accretion disk, shadow and deflection angle with M87* and Sgr A* from EHT
Akhil Uniyal, Reggie C. Pantig, Ali Övgün
Non-linear interaction between the electromagnetic fields (EMF) occurs when vacuum polarization in quantum electrodynamics (QED) happens. The field of non-linear electrodynamics, w…