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A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass
Using the Very Long Baseline Array, we have measured a trigonometric parallax for the micro quasar GRS 1915+105, which contains a black hole and a K-giant companion. This yields a direct distance
The Extreme Spin of the Black Hole in Cygnus X-1
The compact primary in the X-ray binary Cygnus X-1 was the first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, and
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
An Improved Dynamical Model for the Microquasar XTE J1550–564
We present an improved dynamical model of the X-ray binary and microquasar XTE J1550?564 based on new moderate-resolution optical spectroscopy and near-infrared photometry obtained with the 6.5?m
A Simple Comptonization Model
We present an empirical model of Comptonization for fitting the spectra of X-ray binaries. This model, named SIMPL, has been developed as a package implemented in XSPEC. With only two free
The spin of the black hole microquasar XTE J1550−564 via the continuum-fitting and Fe-line methods
We measure the spin of XTE J1550−564 using the two leading methods: (i) modelling the thermal continuum spectrum of the accretion disc; and (ii) modelling the broad red wing of the reflection
Improved Reflection Models of Black Hole Accretion Disks: Treating the Angular Distribution of X-Rays
X-ray reflection models are used to constrain the properties of the accretion disk, such as the degree of ionization of the gas and the elemental abundances. In combination with general relativistic
The Spin of the Black Hole Primary in LMC X-1
The first extragalactic X-ray binary, LMC X-1, was discovered in 1969. In the 1980s, its compact primary was established as the fourth dynamical black hole candidate. Recently, we published accurate
The Spin of the Black Hole in the Soft X-ray Transient A0620--00
During its year-long outburst in 1975-76, the transient source A0620-00 reached an intensity of 50 Crab, an all-time record for any X-ray binary. The source has been quiescent since then. We have
An Embedded X-Ray Source Shines through the Aspherical AT 2018cow: Revealing the Inner Workings of the Most Luminous Fast-evolving Optical Transients
We present the first extensive radio to γ-ray observations of a fast-rising blue optical transient, AT 2018cow, over its first ~100 days. AT 2018cow rose over a few days to a peak luminosity L_(pk) ~