相关论文: Photon Ring Astrometry for Superradiant Clouds

Clouds of ultralight bosons - such as axions - can form around a rapidly spinning black hole, if the black hole radius is comparable to the bosons' wavelength. The cloud rapidly extracts angular momentum from the black hole, and reduces it…

We consider trajectories of massless particles in the presence of charged black holes in asymptotically AdS spacetimes in arbitrary dimensions. We study the properties of the photon ring in the (near-)extremal limit and show that the photon…

Light orbiting an accreting black hole may impact the disk or jet multiple times before escaping to the observer, at a variety of angles with respect to the local magnetic field. In this letter, we characterize the imprints of these long…

I present evidence of a novel guise of superradiance that arises in black hole binary spacetimes. Given the right initial conditions, a wave will be amplified as it scatters off the binary. This process, which extracts energy from the…

Ultracompact objects with photonspheres are known to mimic many observational features of black holes. It has been suggested that anomalous tidal heating or the presence of resonances in gravitational wave signals would be a clear imprint…

Gravitational waves may be one of the few direct observables produced by ultralight bosons, conjectured dark matter candidates that could be the key to several problems in particle theory, high-energy physics and cosmology. These axionlike…

Black holes typically inhabit highly dynamical galactic environments and are frequently permeated by accretion media. The inevitable scattering of scalar, electromagnetic and gravitational waves off rotating and charged black holes provides…

The past decade has transformed our ability to observe the Universe. Via gravitational waves, merging black holes and neutron stars can now be directly detected, offering unprecedented opportunities to test General Relativity and explore…

We investigate the gravitational lensing by Bardeen black hole in cloud of strings (CoS) in strong field limit. The effect of CoS parameter $b$ has been outlined in comparison with Bardeen black hole lens. The strong deflection limit…

The presence of dark matter overdensities surrounding a black hole can influence the evolution of a binary system. The gravitational wave signals emitted by a black hole binary offer a promising means to probe the dark matter environments…

We study the imprints of new ultralight particles on the gravitational-wave signals emitted by binary black holes. Superradiant instabilities may create large clouds of scalar or vector fields around rotating black holes. The presence of a…

A dark matter overdensity around a black hole may significantly alter the dynamics of the black hole's merger with another compact object. We consider here intermediate mass-ratio inspirals of stellar-mass compact objects with…

The superradiance instability of rotating black holes leads to the formation of an ultralight boson cloud with distinctive observational signatures, making black holes an effective probe of ultralight bosons. However, around black holes in…

This research delves into the optical characteristics of stationary, spherically symmetric black holes. These black holes follow the Konoplya-Zhidenko deformation rule in arbitrary gravity theories. This research finds that the effects of…

Gravitational wave detectors are formidable tools to explore strong-field gravity, especially black holes and neutron stars. These compact objects are extraordinarily efficient at producing electromagnetic and gravitational radiation. As…

One of the most compelling candidates for Dark Matter (DM) are light pseudo-scalar particles (axions), motivated by the strong CP problem and axiverse scenario in string theory. Depending on their mass and type of self-interaction, these…

We study extreme mass-ratio binary systems in which a stellar mass compact object spirals into a supermassive black hole surrounded by a scalar cloud. Scalar clouds can form through superradiant instabilities of massive scalar fields around…

Retrolensing is a gravitational lensing effect in which light emitted by a background source is deflected by a black hole and redirected toward the observer after undergoing nearly complete loops around the black hole. In this context, we…

Supermassive black hole binary mergers generate a stochastic gravitational wave background detectable by pulsar timing arrays. While the amplitude of this background is subject to significant uncertainties, the frequency dependence is a…

Ultralight bosons, proposed as candidates for dark matter (DM), are predicted by various new physics models. In the presence of bosons with suitable masses, superradiant (SR) instability can naturally transform a spinning black hole (BH)…