EHT observables as a tool to estimate parameters of supermassive black holes

Abstract

The Event Horizon Telescope (EHT) collaboration unveiled event-horizon-scale images of the supermassive black holes (SMBHs) M87* and Sgr A*, revealing a dark brightness depression, namely the black hole shadow, whose shape and size may encode the parameters of the SMBHs, and the shadow is consistent with that of a Kerr black hole. It furnishes another encouraging tool to estimate black hole parameters and test theories of gravity in extreme regions near the event horizon. We propose a technique that uses EHT observables, the angular shadow diameter $d_{sh}$ and the axis ratio ${\mathcal{D}}_A$, to estimate the parameters associated with SMBHs, described by the Kerr metric. Unlike previous methods, our approach explicitly considers the uncertainties in the measurement of EHT observables. Modelling Kerr--Newman and three rotating regular spacetimes to be M87* and Sgr A* and applying our technique, we estimate the associated charge parameters along with spin. Our method is consistent with the existing formalisms and can be applied to shadow shapes that are more general and may not be circular. We can use the technique for other SMBHs once their EHT observables become accessible. With future, more accurate measurements of the EHT observables, the estimation of various SMBH parameters like the spin and inclination angles of M87* and Sgr A* would be more precise.

arXiv comment9 pages, 5 figures, 2 tables. Matched to the published version

References in corpus (82)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• The Demography of Massive Dark Objects in Galaxy Centres
• Extended Theories of Gravity
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• The M-sigma and M-L Relations in Galactic Bulges and Determinations of their Intrinsic Scatter
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• Formation and evaporation of non-singular black holes
• The Bardeen Model as a Nonlinear Magnetic Monopole
• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• Shadows and strong gravitational lensing: a brief review
• Shadows of Kerr black holes with scalar hair
• Rotating regular black holes
• Measurement of the Kerr Spin Parameter by Observation of a Compact Object's Shadow
• Measuring Black Hole Spin using X-ray Reflection Spectroscopy
• Construction of Regular Black Holes in General Relativity
• Testing the No-Hair Theorem with Observations in the Electromagnetic Spectrum: II. Black-Hole Images
• Shadow of rotating regular black holes
• Stellar dynamics in the central arcsecond of our galaxy
• A Metric for Rapidly Spinning Black Holes Suitable for Strong-Field Tests of the No-Hair Theorem
• Universal Interferometric Signatures of a Black Hole's Photon Ring
• Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies
• Constraints on black-hole charges with the 2017 EHT observations of M87*
• Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets
• The M87 Black Hole Mass from Gas-dynamical Models of Space Telescope Imaging Spectrograph Observations
• Radiative Models of Sgr A* from GRMHD Simulations
• General parametrization of axisymmetric black holes in metric theories of gravity
• Black hole shadow in an asymptotically-flat, stationary, and axisymmetric spacetime: The Kerr-Newman and rotating regular black holes
• Optical properties of black hole in the presence of plasma: shadow
• A coordinate-independent characterization of a black hole shadow
• Black Hole Parameter Estimation from Its Shadow
• Parameter estimation of hairy Kerr black holes from its shadow and constraints from M87*
• Constraining the spin and the deformation parameters from the black hole shadow
• Evidence for Low Black Hole Spin and Physically Motivated Accretion Models from Millimeter VLBI Observations of Sagittarius A*
• Linking Tests of Gravity On All Scales: from the Strong-Field Regime to Cosmology
• Sagittarius A* Accretion Flow and Black Hole Parameters from General Relativistic Dynamical and Polarized Radiative Modeling
• Observational Constraints on the Feeding of Supermassive Black Holes
• Regular black holes with asymptotically Minkowski cores
• On the charge of the Galactic centre black hole
• Quasinormal modes of a black hole surrounded by quintessence
• Measurement of the spin of the M87 black hole from its observed twisted light
• Curvature radius and Kerr black hole shadow
• On a regular charged black hole with a nonlinear electric source
• Sgr A* and General Relativity
• Tests of Loop Quantum Gravity from the Event Horizon Telescope Results of Sgr A${}^{\ast }$
• Measuring the mass of the central black hole in the bulgeless galaxy NGC 4395 from gas dynamical modeling
• Measuring Supermassive Black Hole Spins in Active Galactic Nuclei
• Can the EHT M87 results be used to test general relativity?
• GRay: a Massively Parallel GPU-Based Code for Ray Tracing in Relativistic Spacetimes
• Testing Rotating Regular Metrics as Candidates for Astrophysical Black Holes
• Testing Horndeski Gravity from EHT Observational Results for Rotating Black Holes
• Testing Rotating Regular Metrics with EHT Results of Sgr A*
• A likely decade-long sustained tidal disruption event
• Modeling Seven Years of Event Horizon Telescope Observations with Radiatively Inefficient Accretion Flow Models
• Clouds of strings in third-order Lovelock gravity
• Analytical calculation of black hole spin using deformation of the shadow
• Supermassive Black Holes and the Evolution of Galaxies
• An upper limit on the spin of SgrA${}^{\ast }$ based on stellar orbits in its vicinity
• An Upper Limit on the Charge of the Black Hole Sgr A* from EHT Observations
• Photon ring structure of rotating regular black holes and no-horizon spacetimes
• Constraining spins of supermassive black holes from TeV variability. II. fully general relativistic calculations
• Black Hole Pulsar
• Shadows of black hole surrounded by anisotropic fluid in Rastall theory
• Testing the Bardeen metric with the black hole candidate in Cygnus X-1
• Investigating effects of dark matter on photon orbits and black hole shadows
• Black hole triggered star formation in the dwarf galaxy Henize 2-10
• Testing the accuracy of reflection-based supermassive black hole spin measurements in AGN
• Estimating the cosmological constant from shadows of Kerr--de Sitter black holes
• Shadows of Kerr black holes with a Gaussian-distributed plasma in the polar direction
• Testing the Accretion Flow with Plasma Wave Heating Mechanism for Sagittarius a* by the 1.3MM Vlbi Measurements
• Testing general relativity with the stellar-mass black hole in LMC X-1 using the continuum-fitting method
• Black hole parameter estimation with synthetic Very Long Baseline Interferometry data from the ground and from space
• Broad line region and black hole mass of PKS 1510-089 from spectroscopic reverberation mapping
• The Black Hole Mass of NGC 4151 from Stellar Dynamical Modeling
• Measuring the Ellipticity of M 87* Images
• Exploring higher order images with Fe K_α-lines from relativistic disks: black hole spin determination and bias
• Tidal Disruption Events by Compact Supermassive Black Hole Binaries
• A natural mechanism to induce an electric charge into a black hole

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• Quasinormal modes-shadow correspondence for rotating regular black holes
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• Gravitational signatures of a nonlinear electrodynamics in $f(R,T)$ gravity
• Modified Kerr black holes surrounded by dark matter spike
• Aberration effect on lower-order images of thin accretion disk in the astrometric approach
• Testing black hole space-times with the S2 star orbit: a Bayesian comparison
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• Gravitational aspects of a new bumblebee black hole
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