622 citations · 5.9k across the 90 of their papers we have counts for
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AGN accretion disks as spatially resolved by polarimetry
Makoto Kishimoto, Robert Antonucci, Omer Blaes +4
A crucial difficulty in understanding the nature of the putative accretion disk in AGNs is that some of its key intrinsic spectral signatures cannot be observed directly. The stron…
Radiation-Dominated Disks Are Thermally Stable
Shigenobu Hirose, Julian H. Krolik, Omer Blaes
When the accretion rate is more than a small fraction of Eddington, the inner regions of accretion disks around black holes are expected to be radiation-dominated. However, in the…
The characteristic blue spectra of accretion disks in quasars as uncovered in the infrared
Makoto Kishimoto, Robert Antonucci, Omer Blaes +4
Quasars are thought to be powered by supermassive black holes accreting surrounding gas. Central to this picture is a putative accretion disk which is believed to be the source of…
Epicyclic Motions and Standing Shocks in Numerically Simulated Tilted Black-Hole Accretion Disks
P. Chris Fragile, Omer M. Blaes
This work presents a detailed analysis of the overall flow structure and unique features of the inner region of the tilted disk simulations described in Fragile et al. (2007). The…
The UV Continuum of Quasars: Models and SDSS Spectral Slopes
Shane W. Davis, Jong-Hak Woo, Omer M. Blaes
We measure long (2200-4000 ang) and short (1450-2200 ang) wavelength spectral slopes α(F_νproportional to ν^α) for quasar spectra from the Sloan Digital Sky Survey. The long and sh…
Epicyclic Oscillations of Fluid Bodies: Newtonian Nonslender Torus
Omer M. Blaes, Eva Sramkova, Marek A. Abramowicz +2
We study epicyclic oscillations of fluid tori around black holes (in the Paczynski-Wiita potential) and derive exact analytic expressions for their radial and vertical eigenfrequen…
Global General Relativistic MHD Simulation of a Tilted Black-Hole Accretion Disk
P. Chris Fragile, Omer M. Blaes, Peter Anninos +1
This paper presents a continuation of our efforts to numerically study accretion disks that are misaligned (tilted) with respect to the rotation axis of a Kerr black hole. Here we…
Surface Structure in an Accretion Disk Annulus with Comparable Radiation and Gas Pressure
Omer Blaes, Shigenobu Hirose, Julian H. Krolik
We have employed a 3-d energy-conserving radiation MHD code to simulate the vertical structure and thermodynamics of a shearing box whose parameters were chosen so that the radiati…
Thermodynamics of an Accretion Disk Annulus with Comparable Radiation and Gas Pressure
Julian H. Krolik, Shigenobu Hirose, Omer Blaes
We explore the thermodynamic and global structural properties of a local patch of an accretion disk whose parameters were chosen so that radiation pressure and gas pressure would b…
Accretion Disks in AGNs
Omer Blaes
I briefly review the theoretical models of radiatively efficient, geometrically thin and optically thick accretion disk spectra that currently exist for AGN. I then discuss three r…
3D Relativistic MHD Simulation of a Tilted Accretion Disk Around a Rapidly Rotating Black Hole
P. Chris Fragile, Peter Anninos, Omer M. Blaes +1
We posit that accreting compact objects, including stellar mass black holes and neutron stars as well as supermassive black holes, may undergo extended periods of accretion during…
Turbulent Comptonization in Relativistic Accretion Disks
Aristotle Socrates, Shane W. Davis, Omer Blaes
Turbulent Comptonization, a potentially important damping and radiation mechanism in relativistic accretion flows, is discussed. Particular emphasis is placed on the physical basis…
Quasi-Periodic Oscillations from Magnetorotational Turbulence
Phil Arras, Omer Blaes, Neal J. Turner
Quasi-periodic oscillations (QPOs) in the X-ray lightcurves of accreting neutron star and black hole binaries have been widely interpreted as being due to standing wave modes in ac…
Testing Accretion Disk Theory in Black Hole X-ray Binaries
Shane W. Davis, Chris Done, Omer M. Blaes
We present results from spectral modeling of three black hole X-ray binaries: LMC X-3, GRO J1655-40, and XTE J1550-564. Using a sample of disk dominated observations, we fit the da…
Magnetic pressure support and accretion disk spectra
O. M. Blaes, S. W. Davis, S. Hirose +2
Stellar atmosphere models of ionized accretion disks have generally neglected the contribution of magnetic fields to the vertical hydrostatic support, although magnetic fields are…
Oscillation modes of relativistic slender tori
O. M. Blaes, P. Arras, P. C. Fragile
Accretion flows with pressure gradients permit the existence of standing waves which may be responsible for observed quasi-periodic oscillations (QPO's) in X-ray binaries. We prese…
Epicyclic oscillations of fluid bodies Paper II. Strong gravity
Marek A. Abramowicz, Omer M. Blaes, Jiri Horak +2
Fluids in external gravity may oscillate with frequencies characteristic of the epicyclic motions of test particles. We explicitly demonstrate that global oscillations of a slender…
The Effects of Photon Bubble Instability in Radiation-Dominated Accretion Disks
N. J. Turner, O. M. Blaes, A. Socrates +2
We examine the effects of photon bubble instability in radiation-dominated accretion disks such as those found around black holes in active galactic nuclei and X-ray binary star sy…
The Neutrino Bubble Instability: A Mechanism for Generating Pulsar Kicks
Aristotle Socrates, Omer Blaes, Aimee Hungerford +1
An explanation for the large random velocities of pulsars is presented. Like many other models, we propose that the momentum imparted to the star is given at birth. The ultimate so…
Quasars and the Big Blue Bump
Zhaohui Shang, Michael S. Brotherton, Richard F. Green +10
We investigate the ultraviolet-to-optical spectral energy distributions (SEDs) of 17 active galactic nuclei (AGNs) using quasi-simultaneous spectrophotometry spanning 900-9000 Angs…
Relativistic Accretion Disk Models of High State Black Hole X-ray Binary Spectra
Shane W. Davis, Omer M. Blaes, Ivan Hubeny +1
We present calculations of non-LTE, relativistic accretion disk models applicable to the high/soft state of black hole X-ray binaries. We include the effects of thermal Comptonizat…
Photon Bubbles in Young Massive Stars
N. J. Turner, H. W. Yorke, A. Socrates +1
Spectroscopic studies indicate that gas in the photospheres of young O stars moves at speeds up to the sound speed. We show, using two-dimensional radiation MHD calculations and re…
Effects of Fluid Instabilities on Accretion Disk Spectra
S. W. Davis, O. M. Blaes, N. J. Turner +1
Numerical calculations and linear theory of radiation magnetohydrodynamic flows indicate that the photon bubble and magnetorotational instability (MRI) may produce large density in…
X-ray Reflection from Inhomogeneous Accretion Disks: I. Toy Models and Photon Bubbles
D. R. Ballantyne, N. J. Turner, O. M. Blaes
Numerical simulations of the interiors of radiation dominated accretion disks show that significant density inhomogeneities can be generated in the gas. Here, we present the first…