2.3k citations · 53.2k across the 308 of their papers we have counts for
11 papers · 2 filters
On The Nature of the Compact Dark Mass at the Galactic Center
Avery E. Broderick, Ramesh Narayan
We consider a model in which Sgr A*, the 3.5x10^6 M_sun supermassive black hole candidate at the Galactic Center, is a compact object with a surface. Given the very low quiescent l…
Thermal X-Ray Iron Line Emission from the Galactic Center Black Hole Sagittarius A*
Ya-Di Xu, Ramesh Narayan, Eliot Quataert +2
We model thermal X-ray emission from the accreting supermassive black hole Sagittarius A* at the Galactic Center. For the region inside of the center, we use a…
How Much Mass do Supermassive Black Holes Eat in their Old Age?
Philip F. Hopkins, Ramesh Narayan, Lars Hernquist
We consider the distribution of local supermassive black hole Eddington ratios and accretion rates, accounting for the dependence of radiative efficiency and bolometric corrections…
Fitting Formula for Flux Scintillation of Compact Radio Sources
J. Goodman, R. Narayan
We present a fitting function to describe the statistics of flux modulations caused by interstellar scintillation. The function models a very general quantity: the cross-correlatio…
The Rates of type I X-ray Bursts from Transients Observed with RXTE: Evidence for Black Hole Event Horizons
Ronald A. Remillard, Dacheng Lin, Randall L. Cooper +1
We measure the rates of type I X-ray bursts, as a function of the bolometric luminosity, from a likely complete sample of 37 non-pulsing transients (1996-2004). Our goals are to te…
Estimating the Spin of Stellar-Mass Black Holes via Spectral Fitting of the X-ray Continuum
Rebecca Shafee, Jeffrey E. McClintock, Ramesh Narayan +3
We fit X-ray spectral data in the thermal dominant or high soft state of two dynamically confirmed black holes, GRO J1655-40 and 4U 1543-47, and estimate the dimensionless spin par…
On the Production and Survival of Carbon Fuel for Superbursts on Accreting Neutron Stars: Implications for Mass Donor Evolution
Randall L. Cooper, Banibrata Mukhopadhyay, Danny Steeghs +1
(abridged) We have investigated the physical conditions under which accreting neutron stars can both produce and preserve sufficient quantities of carbon fuel to trigger superburst…
Growth of Hydrodynamic Perturbations in Accretion Disks: Possible Route to Non-Magnetic Turbulence
Banibrata Mukhopadhyay, Niayesh Afshordi, Ramesh Narayan
We study the possible origin of hydrodynamic turbulence in cold accretion disks such as those in star-forming systems and quiescent cataclysmic variables. As these systems are expe…
A Hydrogen Atmosphere Spectral Model Applied to the Neutron Star X7 in the Globular Cluster 47 Tucanae
Craig O. Heinke, George B. Rybicki, Ramesh Narayan +1
Current X-ray missions are providing high-quality X-ray spectra from neutron stars (NSs) in quiescent low-mass X-ray binaries (qLMXBs). This has motivated us to calculate new hydro…
Neutrino-Dominated Accretion and Supernovae
Kazunori Kohri, Ramesh Narayan, Tsvi Piran
We suggest that part of the infalling material during the core-collapse of a massive star goes into orbit around the compact core to form a hot, dense, centrifugally-supported accr…
Hydrodynamic Turbulence in Accretion Disks
Banibrata Mukhopadhyay, Niayesh Afshordi, Ramesh Narayan
Turbulent viscosity in cold accretion disks is likely to be hydrodynamic in origin. We investigate the growth of hydrodynamic perturbations in a small region of a disk, which we mo…