Related papers: Periodically Modulated FRB as Extreme Mass Ratio B…
How a black hole accretes matter and how this process is regulated are fundamental but unsolved questions in astrophysics. In transient black-hole binaries, a lot of mass stored in an accretion disk is suddenly drained to the central black…
We analyze the temporal evolution of accretion onto rotating black holes subject to large-scale magnetic torques. Wind torques alone drive a disk towards collapse in a finite time $\sim t_{ff} E_k/E_B$, where $t_{ff}$ is the initial…
The accretion of dark matter (DM) into astrophysical black holes slowly increases their mass. The rate of this mass accretion depends on the DM model and the model parameters. If this mass accretion effect can be measured accurately enough,…
The origin of current angular momentum (AM) of the black hole (BH) in X-ray binary (XRB) is still unclear, which is related with the birth and/or the growth of the BH. Here we collect the spin parameters $a_{*}$ measured in BH XRBs and find…
FRB 180916.J0158+65 has been found to repeatedly emit fast radio bursts with the period in roughly 16 days. We propose that such periodicity comes from orbit-induced, spin precession of the emitter, which is possibly a neutron star.…
A number of black hole X-ray transients show quasi-periodic oscillations (QPOs) in the optical (ultraviolet) and X-ray bands at the same frequency, which challenge models for production of radiation at these wavelengths. We propose a model…
Modeling the late inspiral and merger of supermassive black holes is central to understanding accretion processes and the conditions under which electromagnetic emission accompanies gravitational waves. We use fully general relativistic,…
We have proposed a generation mechanism of non repeating ( repeating ) fast radio bursts: They arise by axion star collisions with neutron stars ( accretion disks of galactic black holes ). The axion star as coherent state of axions with…
Fast radio bursts (FRBs) are bright, millisecond-duration radio transients originating from extragalactic distances. Their origin is unknown. Some FRB sources emit repeat bursts, ruling out cataclysmic origins for those events. Despite…
The black hole (BH) spin could significantly change the density of dark matter (DM) in its vicinity, creating a mini-spike of the density of DM. The dynamical friction (DF) between DM and the companion star of a BH can provide an efficient…
Since the discovery of FRB 200428 associated with the Galactic SGR 1935+2154, magnetars are considered to power fast radio bursts (FRBs). It is widely believed that magnetars could form by core-collapse (CC) explosions and compact binary…
Recently, repeating fast radio bursts (FRBs) with a period of $P_{\rm FRB}=16.35\pm0.18$ days from FRB 180916.J0158+65 had been reported. It still remains controversial how to give rise to such a periodicity of this FRB. In this Letter,…
We consider the accretion of dark energy by constituent black holes in binary formations during the present epoch of the Universe. In the context of an observationally consistent dark energy model, we evaluate the growth of black holes'…
We discuss the energy loss due to gravitational radiation of binaries composed of exotic objects whose horizon boundary conditions are replaced with reflective ones. Our focus is on the extreme mass-ratio inspirals, in which the central…
We review recent works on the dynamics of circumbinary accretion, including time variability, angular momentum transfer between the disk and the binary, and the secular evolution of accreting binaries. These dynamics can impact stellar…
Many models of gamma-ray bursts (GRBs) involve accretion onto a compact object, usually a black hole, at a mass accretion rate of order a fraction of a solar mass per second. If the accretion disk is larger than a few tens or hundreds of…
In this short review we describe some of the latest endeavours to understand the activity around Black Holes. First, it has been possible to demonstrate that a large part of the electromagnetic emission observed can be interpreted as…
Fast radio burst (FRB) source 20180916B exhibits a 16.33-day periodicity in its burst activity. It is as of yet unclear what proposed mechanism produces the activity, but polarization information is a key diagnostic. Here, we report on the…
X-ray reverberation echoes are assumed to be produced in the strongly distorted spacetime around accreting supermassive black holes. This signal allows us to spatially map the geometry of the inner accretion flow - a region which cannot yet…
Relativistic jets from accreting black holes (BHs) radiate non-thermal emission which is highly variable in different time scales. Magnetic fields anchored to a rotating BH or accretion disc accelerate and collimate jets of the BH systems.…