390 citations · 1.5k across the 20 of their papers we have counts for
21 papers
In-Situ Star Formation in a Thick Disk: A Model for Metal Enrichment of Mrk 573
Hannalore J. Gerling-Dunsmore, Mitchell C. Begelman, Jared A. Goldberg +2
Recent observations of the nearby Seyfert galaxy Mrk 573 found that the galactic nucleus and bicone regions surrounding the jet are significantly metal-enriched. In this paper, we…
Constraints on the Gas Geometry Surrounding Little Red Dots through Narrow-Line Diagnostics
Visal Sok, Erica J. Nelson, Mitchell C. Begelman +10
Little Red Dots (LRDs) are a recently identified population of high-redshift sources, with a common interpretation being accreting black holes embedded within a spherical, opticall…
Electron-positron Pair Production in Global GRMHD Simulations of Black Hole Accretion Flows
Ho-Sang Chan, Jason Dexter, Mitchell C. Begelman
We present global, three-dimensional general relativistic magnetohydrodynamic simulations of accreting black holes that incorporate pair physics. Pairs are modeled as a passive sca…
Pulsational Instability of Quasi-Stars: Interpreting the Variability of Little Red Dots
Matteo Cantiello, Jake B. Hassan, Rosalba Perna +5
The JWST discovery of "Little Red Dots" (LRDs) has revealed a population of compact, red sources at that likely host supermassive black holes (SMBHs). Recent observat…
The Growth of the Central Black Holes in Quasi-stars
Jake Hassan, Rosalba Perna, Matteo Cantiello +3
Observations by JWST have confirmed the presence of supermassive black holes (BHs) at redshifts , lending support to scenarios in which BHs experience rapid growth thro…
Little Red Dots As Late-stage Quasi-stars
Mitchell C. Begelman, Jason Dexter
We argue that the "Little Red Dots" (LRDs) discovered with the James Webb Space Telescope are quasi-stars in their late stages of evolution. Quasi-stars are hypothetical objects pr…
Energy Diffusion and Advection Coefficients in Kinetic Simulations of Relativistic Plasma Turbulence
Kai W. Wong, Vladimir Zhdankin, Dmitri A. Uzdensky +2
Turbulent, relativistic nonthermal plasmas are ubiquitous in high-energy astrophysical systems, as inferred from broadband nonthermal emission spectra. The underlying turbulent non…
Quasi-stars as a Means of Rapid Black Hole Growth in the Early Universe
Eric R. Coughlin, Mitchell C. Begelman
JWST observations demonstrate that supermassive black holes (SMBHs) exist by redshifts , providing further evidence for "direct collapse" black hole (BH) formation, w…
Which came first: supermassive black holes or galaxies? Insights from JWST
Joseph Silk, Mitchell Begelman, Colin Norman +2
Insights from JWST observations suggest that AGN feedback evolved from a short-lived, high redshift phase in which radiatively cooled turbulence and/or momentum-conserving outflows…
Three-dimensional AMR simulations of long-duration Gamma-Ray Burst jets inside massive progenitor stars
Diego López-Cámara, Brian J. Morsony, Micthell C. Begelman +1
We present the results of special relativistic, adaptive mesh refinement, 3D simulations of gamma-ray burst jets expanding inside a realistic stellar progenitor. Our simulations co…
X-ray flares from propagation instabilities in long Gamma-Ray Burst jets
Davide Lazzati, Chris H. Blackwell, Bran J. Morsony +1
We present a numerical simulation of a gamma-ray burst jet from a long-lasting engine in the core of a 16 solar mass Wolf-Rayet star. The engine is kept active for 6000 s with a lu…
Angular Momentum Transfer and Lack of Fragmentation in Self-Gravitating Accretion Flows
Mitchell Begelman, Isaac Shlosman
Rapid inflows associated with early galaxy formation lead to the accumulation of self-gravitating gas in the centers of proto-galaxies. Such gas accumulations are prone to non-axis…
Accretion of low angular momentum material onto black holes: 2D hydrodynamical inviscid case
D. Proga, M. C. Begelman
We report on the first phase of our study of slightly rotating accretion flows onto black holes. We consider inviscid accretion flows with a spherically symmetric density distribut…
Heating, conduction and minimum temperatures in cooling flows
Mateusz Ruszkowski, Mitchell C. Begelman
There is mounting observational evidence from Chandra for strong interaction between keV gas and AGN in cooling flows. It is now widely accepted that the temperatures of cluster co…
Hiding in Plain Sight: Chandra Observations of the Quiescent Neutron Star 4U 2129+47 in Eclipse
Michael Nowak, Sebastian Heinz, Mitchell Begelman
During a previous outburst phase, the neutron star 4U 2129+47 exhibited evidence for a spatially extended corona via broad, partial X-ray eclipses occurring periodically on the 5.2…
Circular polarization from stochastic synchrotron sources
Mateusz Ruszkowski, Mitchell C. Begelman
The transfer of polarized radiation in stochastic synchrotron sources is explored by means of analytic treatment and Monte Carlo simulations. We argue that the main mechanism respo…
Magnetohydrodynamical Non-radiative Accretion Flows in Two-Dimensions
James M. Stone, James E. Pringle
We present the results of axisymmetric, time-dependent magnetohydrodynamic simulations of accretion flows around black holes. The calculations begin from a rotationally supported t…
Discovery of Recurring Soft to Hard State Transitions in LMC X-3
J. Wilms, M. A. Nowak, K. Pottschmidt +3
We present the analysis of an RXTE monitoring campaign of the canonical soft state black hole candidates LMC X-1 and LMC X-3. In contrast to LMC X-1, which does not exhibit any per…
RXTE Monitoring of LMC X-3: Recurrent Hard States
J. Wilms, M. A. Nowak, K. Pottschmidt +4
The black hole candidate LMC X-3 varies by a factor of four in the soft X-rays on a timescale of 200 or 100days. We have monitored LMC X-3 with RXTE in three to four week intervals…
Hydrodynamical Non-radiative Accretion Flows in Two-Dimensions
James M. Stone, James E. Pringle, Mitchell C. Begelman
Two-dimensional (axially symmetric) numerical hydrodynamical calculations of accretion flows which cannot cool through emission of radiation are presented. The calculations begin f…
RXTE Observation of Cygnus X-1: Spectral Analysis
James B. Dove, Jorn Wilms, Michael A. Nowak +2
We present the results of the analysis of the broad-band spectrum of Cygnus X-1 from 3.0 to 200 keV, using data from a 10 ksec observation by the Rossi X-ray Timing Explorer. The s…