Related papers: Periodic X-ray Modulation and its relation with or…

We study the timing and spectral properties of the intermediate polar MU Camelopardalis (1RXS J062518.2+733433) to determine the accretion modes and the accretion geometry from multi-wavelength, multi-epoch observational data. Light curves…

Black hole binary systems can emit very bright and rapidly varying X-ray signals when material from the companion accretes onto the black hole, liberating huge amounts of gravitational potential energy. Central to this process of accretion…

Variable active galactic nuclei showing periodic light curves have been proposed as massive black hole binary (MBHB) candidates. In such scenarios the periodicity can be due to relativistic Doppler-boosting of the emitted light. This…

X-ray variability of accreting black hole binaries is believed to be produced by the fluctuations propagating towards the compact object. Observations suggest the light curves in different energy bands are connected, but the fluctuations at…

Given the absence of observations of black hole binaries, it is critical that the full range of accessible parameter space be explored in anticipation of future observation with gravitational wave detectors. To this end, we compile the…

In this paper we continue the first ever study of magnetized mini-disks coupled to circumbinary accretion in a supermassive binary black hole (SMBBH) approaching merger reported in Bowen et al. 2018. We extend this simulation from 3 to 12…

We discuss the conditions under which plane electromagnetic and gravitational waves can be amplified by a rotating black hole due to superradiant scattering. We show, in particular, that amplification can occur for low-frequency waves with…

Binaries containing a compact object orbiting a supermassive black hole are thought to be precursors of gravitational wave events, but their identification has been extremely challenging. Here, we report quasi-periodic variability in X-ray…

As 2 black holes bound to each other in a close binary approach merger their inspiral time becomes shorter than the characteristic inflow time of surrounding orbiting matter. Using an innovative technique in which we represent the changing…

We study the dynamics of merging compact binaries near a rotating supermassive black hole (SMBH) in a hierarchical triple configuration. We include various general relativistic effects that couple the inner orbit, the outer orbit and the…

We compare the peak optical luminosity with the orbital period for a sample of 22 stellar-mass black hole candidates with good measurements of both quantities. We find that the peak absolute magnitude for the outbursts follows a linear…

X-rays produced by compact flares co-rotating with a Keplerian accretion disc are modulated in time by Doppler effects. We improve on previous calculations of these effects by considering recent models of intrinsic X-ray variability, and…

A significant number of X-ray binaries are now known to exhibit long-term ``superorbital'' periodicities on timescales of $\sim$ 10 - 100 days. Several physical mechanisms have been proposed that give rise to such periodicities, in…

X-ray binaries exhibit complex variability patterns studied in the power-spectrum. These include the broad-band noise (BBN) components and various types of narrow components called quasi-periodic oscillations (QPOs). There is currently no…

Accretion discs around black holes in X-ray binary stars are warped if the spin axis of the black hole is not perpendicular to the binary orbital plane. They can also become eccentric through an instability involving a resonance with the…

We show that under certain astrophysical conditions a binary system consisting of two compact objects can be stabilized against indefinite shrinking of orbits due to the emission of gravitational radiation. In this case, the lighter binary…

Recently, evidence for synchrotron emission in both black hole and neutron star X-ray binaries has been mounting, from optical/infrared spectral, polarimetric, and fast timing signatures. The synchrotron emission of jets can be highly…

We study zoom-whirl behaviour of equal mass, non-spinning black hole binaries in full general relativity. The magnitude of the linear momentum of the initial data is fixed to that of a quasi-circular orbit, and its direction is varied. We…

The predicted orbital-period distribution of the subdwarf-B (sdB) population is bi-modal with a peak at short (< 10 days) and long (> 500 days) periods. Observationally, many short-period sdB systems are known, but only few wide sdB…

Five years of Rossi X-ray Timing Explorer (RXTE) observations of the Galactic black-hole candidates 1E 1740.7-2942 and GRS 1758-258 show a periodic modulation with amplitude 3-4% in each source at 12.73 +/- 0.05 dy and 18.45 +/- 0.10 dy,…