B. Krishnan
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Quasi-local black hole horizons: recent advances Open
While the early literature on black holes focused on event horizons, subsequently it was realized that their teleological nature makes them unsuitable for many physical applications both in classical and quantum gravity. Therefore, over th…
Gating-and-inpainting perspective on GW150914 ringdown overtone: Understanding the data analysis systematics Open
We revisit the recent debate on the evidence for an overtone in the black hole ringdown of GW150914 using an independent data-analysis pipeline. By gating and inpainting the data, we discard the contamination from earlier parts of the grav…
Dynamical horizon segments and spacetime isometries Open
Given a space-time $(\mathscr{M}, g_{ab})$ admitting a dynamical horizon segment (DHS) $\mathscr{H}$, we show that there are stringent constraints on the Killing fields $ξ^a$ that $g_{ab}$ can admit in a neighborhood of $\mathscr{H}$: Gene…
View article: Black hole spectroscopy: from theory to experiment
Black hole spectroscopy: from theory to experiment Open
The "ringdown" radiation emitted by oscillating black holes has great scientific potential. By carefully predicting the frequencies and amplitudes of black hole quasinormal modes and comparing them with gravitational-wave data from compact…
Can Neutron Star Tidal Effects Obscure Deviations from General Relativity? Open
One of the main goals of gravitational-wave astrophysics is to study gravity in the strong-field regime and constrain deviations from general relativity (GR). Any such deviation affects not only binary dynamics and gravitational-wave emiss…
Quasi-Local Black Hole Horizons: Recent Advances Open
While the early literature on black holes focused on event horizons, subsequently it was realized that their teleological nature makes them unsuitable for many physical applications both in classical and quantum gravity. Therefore, over th…
Black Hole Tomography: Unveiling Black Hole Ringdown via Gravitational Wave Observations Open
During the post-merger regime of a binary black hole merger, the gravitational wave signal consists of a superposition of quasi-normal modes (QNMs) of the remnant black hole. It has been observed empirically, primarily through numerical si…
Can Neutron Star Tidal Effects Obscure Deviations from General Relativity? Open
One of the main goals of gravitational-wave astrophysics is to study gravity in the strong-field regime and constrain deviations from general relativity (GR). Any such deviation affects not only binary dynamics and gravitational-wave emiss…
Estimating false alarm rates of sub-dominant quasi-normal modes in GW190521 Open
A major aim of gravitational wave astronomy is to test observationally the Kerr nature of black holes. The strongest such test, with minimal additional assumptions, is provided by observations of multiple ringdown modes, also known as blac…
Tidal deformations of slowly spinning isolated horizons Open
It is generally believed that tidal deformations of a black hole in an external field, as measured using its gravitational field multipoles, vanish. However, this does not mean that the black hole horizon is not deformed. Here we shall dis…
Properties of quasilocal mass in binary black hole mergers Open
Contains fulltext : 300871.pdf (Publisher’s version ) (Open Access)
Estimating False Alarm Rates of Sub-Dominant Quasi-normal Modes in GW190521 Open
Data release for "Estimating False Alarm Rates of Sub-Dominant Quasi-normal Modes in GW190521" [arXiv:2209.00640]. Included are data files and scripts needed to generate figures and values that calculate the probability of getting Bayes fa…
Nonlinear Ringdown at the Black Hole Horizon Open
The gravitational waves emitted by a perturbed black hole ringing down are well described by damped sinusoids, whose frequencies are those of quasinormal modes. Typically, first-order black hole perturbation theory is used to calculate the…
Multimode Quasinormal Spectrum from a Perturbed Black Hole Open
When two black holes merge, the late stage of gravitational wave emission is a superposition of exponentially damped sinusoids. According to the black hole no-hair theorem, this ringdown spectrum depends only on the mass and angular moment…
Spectroscopy for asymmetric binary black hole mergers Open
We study Bayesian inference of black hole ringdown modes for simulated binary black hole signals. We consider to what extent different fundamental ringdown modes can be identified in the context of black hole spectroscopy. Our simulated si…
A gating-and-inpainting perspective on GW150914 ringdown overtone: understanding the data analysis systematics Open
We revisit the recent debate on the evidence for an overtone in the black hole ringdown of GW150914 using an independent data-analysis pipeline. By gating and inpainting the data, we discard the contamination from earlier parts of the grav…
Spectroscopy for asymmetric binary black hole mergers Open
We study Bayesian inference of black hole ringdown modes for simulated binary black hole signals. We consider to what extent different fundamental ringdown modes can be identified in the context of black hole spectroscopy. Our simulated si…
Properties of Quasi-local mass in binary black hole mergers Open
Identifying a general quasi-local notion of energy-momentum and angular momentum would be an important advance in general relativity with potentially important consequences for mathematical and astrophysical studies in general relativity. …
Nonlinear ringdown at the black hole horizon Open
The gravitational waves emitted by a perturbed black hole ringing down are well described by damped sinusoids, whose frequencies are those of quasinormal modes. Typically, first-order black hole perturbation theory is used to calculate the…
Universality in binary black hole dynamics: An integrability conjecture Open
The waveform of a binary black hole coalescence appears to be both simple and universal. In this essay we argue that the dynamics should admit a separation into “fast and slow” degrees of freedom, such that the latter are described by an i…
Universality in Binary Black Hole Dynamics: An Integrability Conjecture Open
The waveform of a binary black hole coalescence appears to be both simple and universal. In this essay we argue that the dynamics should admit a separation into 'fast and slow' degrees of freedom, such that the latter are described by an i…
Using Gravitational Waves to Distinguish between Neutron Stars and Black Holes in Compact Binary Mergers Open
In 2017 August, the first detection of a binary neutron star merger, GW170817, made it possible to study neutron stars in compact binary systems using gravitational waves. Despite being the loudest gravitational-wave event detected to date…
Painlevé-II approach to binary black hole merger dynamics: universality from integrability Open
The binary black hole merger waveform is both simple and universal. Adopting an effective asymptotic description of the dynamics, we aim at accounting for such universality in terms of underlying (effective) integrable structures. More spe…
Airy-function approach to binary black hole merger waveforms: The fold-caustic diffraction model Open
From numerical simulations of the Einstein equations, and also from gravitational wave observations, the gravitational wave signal from a binary black hole merger is seen to be simple and to possess certain universal features. The simplici…
Model systematics in time domain tests of binary black hole evolution Open
\n Contains fulltext :\n 249789.pdf (Publisher’s version ) (Open Access)\n
Tidal deformation of dynamical horizons in binary black hole mergers Open
\n Contains fulltext :\n 247417.pdf (Publisher’s version ) (Open Access)\n
Testing gravitational waveform models using angular momentum Open
The anticipated enhancements in detector sensitivity and the corresponding increase in the number of gravitational wave detections will make it possible to estimate parameters of compact binaries with greater accuracy assuming general rela…
Testing waveform models using angular momentum Open
The anticipated enhancements in detector sensitivity and the corresponding increase in the number of gravitational wave detections will make it possible to estimate parameters of compact binaries with greater accuracy assuming general rela…
Observation of a multimode quasi-normal spectrum from a perturbed black hole Open
When two black holes merge, the late stage of gravitational wave emission is a superposition of exponentially damped sinusoids. According to the black hole no-hair theorem, this ringdown spectrum depends only on the mass and angular moment…