Publications (11)
Polarization signature of gamma-ray bursts from fragmented fireballs
Davide Lazzati, Mitchell Begelman
We study the polarization properties of the prompt emission of gamma-ray bursts produced by fragmented fireballs. Such fireballs, known in the literature under various names, are m…
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…
Direct Collapse to Supermassive Black Hole Seeds with Radiative Transfer: Isolated Halos
Yang Luo, Kazem Ardaneh, Isaac Shlosman +3
Direct collapse within dark matter (DM) halos is a promising path to form supermassive black hole (SMBH) seeds at high redshifts. The outer part of this collapse remains optically…
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…
Universal GRB jets from jet-cocoon interaction in massive stars
Davide Lazzati, Mitchell Begelman
We consider the time-dependent evolution of a relativistic jet following its breakout through the surface of a massive compact star, as envisaged in the collapsar model of gamma-ra…
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…
Variability, Power, and Pair Content of AGN Jets
Marek Sikora, Greg Madejski, Mitchell Begelman
Simultaneous observations of blazars in different spectral regimes imply that the amplitude of variability depends on the observational band. Both in the low energy spectral compon…
Astro2020 Science White Paper: Using X-Ray Polarimetry to Probe the Physics of Black Holes and Neutron Stars
Henric Krawczynski, Giorgio Matt, Adam R. Ingram +54
This white paper highlights compact object and fundamental physics science opportunities afforded by high-throughput broadband (0.1-60 keV) X-ray polarization observations. X-ray p…
Kinetic Simulations of Imbalanced Turbulence in a Relativistic Plasma: Net Flow and Particle Acceleration
Amelia Hankla, Vladimir Zhdankin, Gregory Werner +2
Turbulent high-energy astrophysical systems often feature asymmetric energy injection: for instance, Alfven waves propagating from an accretion disk into its corona. Such systems a…
Persistence of the Millihertz X-ray Quasi-Periodic Oscillation in the Active Galactic Nucleus 1ES 1927+654
Megan Masterson, Erin Kara, William N. Alston +15
1ES 1927+654 is an extreme active galactic nucleus (AGN) that has defied our canonical expectations for how AGN appear across the electromagnetic spectrum and how they vary on shor…
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…