Related papers: Spin Constraints on 4U 1630-47 via combined Contin…

X-ray reflection is a very powerful method to assess the spin of supermassive black holes (SMBHs) in active galactic nuclei (AGN), yet this technique is not universally accepted. Indeed, complex reprocessing (absorption, scattering) of the…

In astronomy, the problem of black holes is arguably second in importance only to the problem of cosmology. A current frontier in black hole research is the measurement of spin. During the past three years, the spins of several stellar-mass…

Robustly measuring binary black hole spins via gravitational waves is key to understanding these systems' astrophysical origins, but remains challenging -- especially for high-mass systems, whose signals are short and dominated by the…

Studying the reflection of X-rays off the inner edge of the accretion disk in a neutron star low-mass X-ray binary, allows us to investigate the accretion geometry and to constrain the radius of the neutron star. We report on a NuSTAR…

We present a systematic analysis of the complete set of observations of the neutron star low-mass X-ray binary 4U1608-52 obtained by the Rossi X-ray Timing Explorer's Proportional Counter Array. We study the spectral and fast-time…

We present a comprehensive spectro-polarimetric study of persistent Black hole X-ray binary 4U $1957\!+\!115$ with {\it IXPE} and {\it NICER} observations. The source is observed in disk dominated thermal state with disk temperature,…

We present results from the Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the new black hole X-ray binary candidate MAXI J1631-479 at two epochs during its 2018-2019 outburst, which caught the source in a disk dominant…

High-accuracy binary black hole simulations are presented for black holes with spins anti-aligned with the orbital angular momentum. The particular case studied represents an equal-mass binary with spins of equal magnitude S/m^2=0.43757 \pm…

In a previous paper, we presented an extension of our reflection model RELXILL_NK to include the finite thickness of the accretion disk following the prescription in Taylor & Reynolds (2018). In this paper, we apply our model to fit the…

The continuum-fitting method is one of the two most advanced methods of determining the black hole spin in accreting X-ray binary systems. There are, however, still some unresolved issues with the underlying disk models. One of them…

We investigate the detectability of sub-dominant spin effects in merging black-hole binaries using current gravitational-wave data. Using a phenomenological model that separates the spin dynamics into precession (azimuthal motion) and…

We report the results from an X-ray and near-infrared observation of the Galactic black hole binary 4U 1630--47 in the very high state, performed with {\it Suzaku} and IRSF around the peak of the 2012 September-October outburst. The X-ray…

Swift J1727.8--1613 is a black hole X-ray binary newly discovered in 2023. We perform spectral analysis with simultaneous Insight-HXMT, NICER and NuSTAR observations when the source was approaching to the hard intermediate state. Such a…

Black hole (BH) superradiance can provide strong constraints on the properties of ultralight bosons (ULBs). While most of the previous work has focused on the theoretical predictions, here we investigate the most suitable statistical…

We investigate the possible nonlinear variability properties of the black hole X-ray nova 4U1543-47 to complement the temporal studies based on linear techniques, and to search for signs of nonlinearity in Galactic black hole (GBH) light…

The X-ray light curves of accreting black holes and neutron stars in binary systems show various types of quasi-periodic oscillations (QPOs), the origin of which is still debated. The Relativistic Precession Model identifies the QPO…

We report on a deep Suzaku observation of the stellar-mass black hole GX 339-4 in outburst. A clear, strong, relativistically-shaped iron emission line from the inner accretion disk is observed. The broad-band disk reflection spectrum…

We present a re-analysis of the XMM-Newton and NuSTAR observing campaign for the well-studied, X-ray-bright AGN MCG-06-30-15. In particular, we consider a disc model with finite thickness. By fitting the disc reflection spectra in the data,…

Astrophysical black hole systems are the ideal laboratories for testing Einstein's theory of gravity in the strong field regime. We have recently developed a framework which uses the reflection spectrum of black hole systems to perform…

During its 2003 outburst, the black-hole X-ray transient H1743-322 produced two-sided radio and X-ray jets. Applying a simple and symmetric kinematic model to the trajectories of these jets, we determine the source distance, 8.5 \pm 0.8…