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Observational Evidence for a Correlation Between Jet Power and Black Hole Spin
Ramesh Narayan, Jeffrey E. McClintock
We show that the 5-GHz radio flux of transient ballistic jets in black hole binaries correlates with the dimensionless black hole spin parameter a* estimated via the continuum-fitt…
Global Structure of Optically Thin, Magnetically Supported, Two-Temperature, Black Hole Accretion Disks
Hiroshi Oda, Mami Machida, Kenji E. Nakamura +2
We present global solutions of optically thin, two-temperature black hole accretion disks incorporating magnetic fields. We assume that the πϕ-component of the Maxwell stress is pr…
Efficient Generation of Jets from Magnetically Arrested Accretion on a Rapidly Spinning Black Hole
Alexander Tchekhovskoy, Ramesh Narayan, Jonathan C. McKinney
We describe global, 3D, time-dependent, non-radiative, general-relativistic, magnetohydrodynamic simulations of accreting black holes (BHs). The simulations are designed to transpo…
Variability in Blazars: Clues from PKS 2155-304
Ramesh Narayan, Tsvi Piran
Rapid variability on a time scale much faster than the light-crossing time of the central supermassive black hole has been seen in TeV emission from the blazar PKS 2155-304. The mo…
The Birth of a Relativistic Outflow in the Unusual γ-ray Transient Swift J164449.3+573451
B. A. Zauderer, E. Berger, A. M. Soderberg +24
Active galactic nuclei (AGN), powered by long-term accretion onto central supermassive black holes, produce relativistic jets with lifetimes of greater than one million yr that pre…
The Extreme Spin of the Black Hole in Cygnus X-1
Lijun Gou, Jeffrey E. McClintock, Mark J. Reid +7
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 a…
The Mass of the Black Hole in Cygnus X-1
Jerome A. Orosz, Jeffrey E. McClintock, Jason P. Aufdenberg +4
Cygnus X-1 is a binary star system that is comprised of a black hole and a massive giant companion star in a tight orbit. Building on our accurate distance measurement reported in…
The Trigonometric Parallax of Cygnus X-1
Mark J. Reid, Jeffrey E. McClintock, Ramesh Narayan +3
We report a direct and accurate measurement of the distance to the X-ray binary Cygnus X-1, which contains the first black hole to be discovered. The distance of 1.86 (-0.11,+0.12)…
Constraints on Cold Magnetized Shocks in Gamma-Ray Bursts
Ramesh Narayan, Pawan Kumar, Alexander Tchekhovskoy
We consider a model in which the ultra-relativistic jet in a gamma-ray burst (GRB) is cold and magnetically accelerated. We assume that the energy flux in the outflowing material i…
The Cool Accretion Disk in ESO 243-49 HLX-1: Further Evidence of an Intermediate Mass Black Hole
Shane W. Davis, Ramesh Narayan, Yucong Zhu +5
With an inferred bolometric luminosity exceeding 10^42 erg/s, HLX-1 in ESO 243-49 is the most luminous of ultraluminous X-ray sources and provides one of the strongest cases for th…
Measuring Black Hole Spin by the Continuum-Fitting Method: Effect of Deviations from the Novikov-Thorne Disc Model
Akshay K. Kulkarni, Robert F. Penna, Roman V. Shcherbakov +7
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 t…
Measuring the Spins of Accreting Black Holes
Jeffrey E. McClintock, Ramesh Narayan, Shane W. Davis +6
A typical galaxy is thought to contain tens of millions of stellar-mass black holes, the collapsed remnants of once massive stars, and a single nuclear supermassive black hole. Bot…