Related papers: A Synchronized Spin Model for Black-Hole Accretion…
The evolution of the spin and tilt of black holes in compact black hole - neutron star and black hole - black hole binary systems is investigated within the framework of the coalescing compact star binary model for short gamma ray bursts…
We report results from simulations in general relativity of magnetized disks accreting onto merging black hole binaries, starting from relaxed disk initial data. The simulations feature an effective, rapid radiative cooling scheme as a…
Observations are providing increasingly detailed quantitative information about the accretion flows that power such high energy systems as X-ray binaries and active galactic nuclei. Analytic models of such systems must rely on assumptions…
When galaxies collide, dynamical friction drives their central supermassive black holes close enought to each other such that gravitational radiation becomes the leading dissipative effect. Gravitational radiation takes away energy,…
The spin is an important but poorly constrained parameter for describing supermassive black holes (SMBHs). Using the continuity equation of SMBH number density, we explicitly obtain the mass-dependent cosmological evolution of the radiative…
In a recent paper arXiv:0709.0299, we introduced a spin expansion that provides a simple yet powerful way to understand aspects of binary black hole (BBH) merger. This approach relies on the symmetry properties of initial and final…
We study the spin dynamics of individual black holes in a binary system. In particular we focus on the polar precession of spins and the possibility of a complete flip of spins with respect to the orbital plane. We perform a full numerical…
Structured jets are recently invoked to explain the complex emission of gamma ray bursts, such as GW 170817. Based on the accretion simulations, the jets are expected to have a structure that is more complex than a simple top-hat. Also, the…
Astrophysical black holes (BHs) have two fundamental properties: mass and spin. While the mass-evolution of BHs has been extensively studied, much less work has been done on predicting the distribution of BH spins. In this paper we present…
Recent work paints a conflicting portrait of the distribution of black hole spins in merging binaries measured with gravitational waves. Some analyses find that a significant fraction of merging binaries contain at least one black hole with…
We interpret the rapid correlated UV/optical/ X-ray variability of XTE J1118+480 as a signature of the coupling between the X-ray corona and a jet emitting synchrotron radiation in the optical band. We propose a scenario in which the jet…
We present new insights into the phenomenology of post-Newtonian spin precession in black-hole binaries. Using multi-timescale methods, previous work has shown that the precession and nutation dynamics in such systems can be classified into…
Attempts to understand the formation of binary black hole (BBH) systems detected via gravitational wave (GW) emission are affected by many unknowns and uncertainties, from both the observational and theoretical (astrophysical modelling)…
We have identified the presence of large-scale, low-frequency dynamo cycles in a long-duration, global, magnetohydrodynamic (MHD) simulation of black hole accretion. Such cycles had been seen previously in local shearing box simulations,…
Accretion disk reflection spectra, including broad iron emission lines, bear the imprints of the strong Doppler shifts and gravitational red-shifts close to black holes. The extremity of these shifts depends on the proximity of the…
We describe a program that we have embarked on to estimate the spins of stellar-mass black holes in X-ray binaries. We fit the continuum X-ray spectrum of the radiation from the accretion disk using the standard thin disk model, and extract…
I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black…
To model the interior of a black hole, a study is made of a spin system with long-range random four-spin couplings that exhibits quantum chaos. The black hole limit corresponds to a system where the microstates are approximately degenerate…
Recent calculations of the recoil velocity in black-hole binary mergers have found kick velocities of $\approx2500 $km/s for equal-mass binaries with anti-aligned initial spins in the orbital plane. In general the dynamics of spinning black…
We report the first 3D general relativistic magnetohydrodynamic (GRMHD) simulation that captures the full, self-consistent evolution from the late inspiral through merger and subsequent recoil of a supermassive binary black hole (SMBBH)…