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Full-Text Articles in Cosmology, Relativity, and Gravity

Constraints On Very High Energy Emission From Grb 130427a, P. T. Reynolds, Et Al Oct 2014

Constraints On Very High Energy Emission From Grb 130427a, P. T. Reynolds, Et Al

Physical Sciences Publications

Prompt emission from the very fluent and nearby (z = 0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-Ray Space Telescope for ~70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that …


Elvis: Exploring The Local Volume In Simulations, Shea Garrison-Kimmel, Michael Boylan-Kolchin, James S. Bullock, Kyle Lee Jan 2014

Elvis: Exploring The Local Volume In Simulations, Shea Garrison-Kimmel, Michael Boylan-Kolchin, James S. Bullock, Kyle Lee

Mathematics, Physics, and Computer Science Faculty Articles and Research

We introduce a set of high-resolution dissipationless simulations that model the Local Group (LG) in a cosmological context: Exploring the Local Volume in Simulations (ELVIS). The suite contains 48 Galaxy-size haloes, each within high-resolution volumes that span 2-5 Mpc in size, and each resolving thousands of systems with masses below the atomic cooling limit. Half of the ELVIS galaxy haloes are in paired configurations similar to the Milky Way (MW) and M31; the other half are isolated, mass-matched analogues. We find no difference in the abundance or kinematics of substructure within the virial radii of isolated versus paired hosts. On …