Related papers: How well can we measure supermassive black hole sp…
Measurements of the angular momentum (spin) of astrophysical black holes are extremely important, as they provide information on the black hole formation and evolution. We present simulated observations of a X-ray binary system with the…
Accurately inferring black hole spin is crucial for understanding black hole dynamics and their astrophysical environments. In this work, we outline a geometric method for spin estimation by using the interferometric shape of the first…
Supermassive black hole (BH) mergers produce powerful gravitational wave (GW) emission. Asymmetry in this emission imparts a recoil kick to the merged BH, which can eject the BH from its host galaxy altogether. Recoiling BHs could be…
Active Galactic Nuclei (AGN) display complex X-ray spectra which exhibit a variety of emission and absorption features, that are commonly interpreted as a combination of i) a relativistically smeared reflection component, resulting from the…
To date, close to fifty presumed black hole binary mergers were observed by the LIGO and Virgo detectors. The analyses have been done with an assumption that these objects are black holes by limiting the spin prior to the Kerr bound.…
The relativistically-broadened reflection spectrum, observed in both AGN and X-ray binaries, has proven to be a powerful probe of the properties of black holes and the environments in which they reside. Being emitted from the inner-most…
The X-ray spectra of accretion discs of eight stellar-mass black holes have been analyzed to date using the thermal continuum fitting method, and the spectral fits have been used to estimate the spin parameters of the black holes. However,…
We present a broad-band analysis of deep Suzaku observations of nearby Seyfert 1 AGN: Fairall 9, MCG--6-30-15, NGC 3516, NGC 3783 and NGC 4051. The use of deep observations (exposures >200 ks) with high S/N allows the complex spectra of…
We attempt to constrain the black hole spin in GX 339-4 from spectral fitting of disc dominated data using RXTE spectra from the three most recent outbursts. We use the best current models for the disc emission, including full radiative…
X-ray reflection spectroscopy is a powerful tool to probe the strong gravity region around black holes, but the available relativistic reflection models have a number of simplifications that lead to systematic uncertainties (not fully under…
The central supermassive black hole of the galaxy M87 is currently a target for precision spin measurement using high-resolution, horizon-scale imaging. Such observations aim to resolve the first lensed (${n}~{=}~{1}$) sub-image of the…
By investigating the time-variable 230 GHz images using ray-tracing general relativistic radiative transfer calculation, we propose a novel method for estimating the spin parameter of the supermassive black hole at the M87 center by…
Doppler tomography can provide a powerful means of determining black hole spin when our view to the central regions are revealed and obscured by optically thick orbiting material, and can provide an independent estimate that does not suffer…
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…
The fourth gravitational-wave transient catalog, GWTC-4.0, reports 153 binary black hole mergers with false-alarm rates $<1,\mathrm{yr}^{-1}$. Chirp masses are typically measured well, with the smallest fractional uncertainty being $2%$ at…
Mass and spin are the only two parameters needed to completely characterize black holes in General Relativity. However, the interaction between black holes and their environment is where complexity lies, as the relevant physical processes…
GRS 1915+105 harbors one of the most massive known stellar black holes in the Galaxy. In May 2007, we observed GRS 1915+105 for 117 ksec in the low/hard state using Suzaku. We collected and analyzed the data with the HXD/PIN and XIS cameras…
We report the results of fitting Insight-HXMT data to the black hole X-ray binary MAXI J1348-430, which was discovered on January 26th, 2019, with the Gas Slit Camera (GSC) on-board MAXI. Several observations at the beginning of the first…
4U 1543-47 is a low mass X-ray binary which harbours a stellar-mass black hole located in our Milky Way galaxy. In this paper, we revisit 7 data sets which were in the Steep Power Law state of the 2002 outburst. The spectra were observed by…
Fitting the thermal continuum emission of accreting black holes observed across X-ray bands represents one of the principle means of constraining the properties (mass and spin) of astrophysical black holes. Recent ''continuum fitting''…