Related papers: Spectral/timing evolution of black-hole binaries
Over the past half century, X-ray and radio observations of accreting neutron stars and stellar mass black holes have yielded a rich observational picture with common features including state transitions and jet formation, but also sharp…
We model non-thermal emission spectrum of the extremely sub-Eddington X-ray binary system A0620-00. It is believed that this non-thermal emission is produced by a radiatively inefficient "quiescent" accretion onto a stellar-mass black hole…
We study a novel electromagnetic signature of supermassive black hole binaries whose inspiral starts being dominated by gravitational wave (GW) emission. Recent simulations suggest that the binary's member BHs can continue to accrete gas…
We show that the radio emission of black hole (BH) and neutron star (NS) X-ray binaries (XRBs) follows the analytical prediction of a jet model where the jet carries a constant fraction of the accretion power. The radio emission can…
Determining whether black hole jets are dominated by leptonic or baryonic matter remains an open question in high-energy astrophysics. We propose that extreme mass ratio binary (EMRB) black holes, where an intermediate mass secondary black…
Most transient black hole X-ray binaries (BHXBs) spend the bulk of their time in a quiescent state, where they accrete matter from their companion star at highly sub-Eddington luminosities (we define quiescence here as a normalized…
Spontaneous scalarization of black holes typically occurs through the condensation of a scalar field, with the field evolving from a $U(1)$-symmetric phase into a symmetry-breaking one with lower energy. We show that there exist…
We present results of recent observations and theoretical modeling of data from black holes accreting at very low luminosities (L/L_Edd ~ 10^{-8}). We discuss our newly developed time-dependent model for episodic ejection of relativistic…
Using high-resolution general relativistic magnetohydrodynamic (GRMHD) simulations, we investigate accretion flows around spinning black holes and identify three distinct accretion states. Our results suggest the origin of the complex…
The spectral and temporal evolution during X-ray outbursts give important clues on the accretion process and radiation mechanism in black-hole X-ray binaries (BH XRBs). A set of Swift and RXTE observations were executed to monitor the 2008…
We report on our attempt to understand the outbursting profile of Galactic Black Hole (GBH) sources, keeping in mind the evolution of temporal and spectral features during the outburst. We present results of evolution of Quasi-periodic…
We study time evolution and gravitational wave emission properties of a black hole orbiting {\it inside} an accretion disk surrounding a massive black hole. We simultaneously solve the structure equations of the accretion disk in presence…
We explore the hardening of a massive black hole binary embedded in a circum-binary gas disc when the binary and the gas are coplanar and the gas is counter-rotating. The secondary black hole, revolving in the direction opposite to the gas,…
The galactic black hole binary systems give an observational template showing how the accretion flow changes as a function of increasing mass accretion rate, or L/L_Edd. These data can be synthetised with theoretical models of the accretion…
This paper surveys our current knowledge of the hard X-ray emission properties of old accreting neutron stars in low mass X-ray binaries. Hard X-ray components extending up to energies of a few hundred keV have been clearly detected in…
Relativistic jets are launched from black hole (BH) X-ray binaries and active galactic nuclei when the disk accretion rate is below a certain limit (i.e., when the ratio of the accretion rate to the Eddingtion accretion rate, $\dot{m}$, is…
Relativistic jets powered by stellar mass black holes in X-ray binaries appear to come in two types: steady outflows associated with hard X-ray states and large scale discrete ejections associated with transient outbursts. We show that the…
we propose a jet model for the low/hard state of black-hole X-ray sources which explains a) the X-ray spectra, b) the timelag spectra, c) the increase in the amplitude (QPO and high frequency) with increasing photon energy, and d) the…
We develop a model for supermassive black hole binaries (SMBHBs) accreting below their Eddington limit, focusing on systems where hot, advection-dominated flows become viable. We specifically explore the spectral appearance of…
Recent breakthroughs in the field of numerical relativity have led to dramatic progress in understanding the predictions of General Relativity for the dynamical interactions of two black holes in the regime of very strong gravitational…