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Full-Text Articles in Astrophysics and Astronomy

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 …


Closed String Thermodynamics And A Blue Tensor Spectrum, Robert H. Brandenberger, Ali Nayeri, Subodh P. Patil Jan 2014

Closed String Thermodynamics And A Blue Tensor Spectrum, Robert H. Brandenberger, Ali Nayeri, Subodh P. Patil

Mathematics, Physics, and Computer Science Faculty Articles and Research

The BICEP-2 team has recently reported the positive detection of cosmic microwave background Bmode polarization. Although uncertainties due to galactic dust foregrounds remain, it is a constructive exercise to work out the implications of presuming some part of the detected B-mode signal to be due to primordial gravitational waves. Were a positive detection of a tensor-to-scalar ratio larger than r greater than or similar to O(10(-2)) confirmed, detecting a tilt in the tensor spectrum comparable to that observed for the scalar power spectrum becomes in principle possible. We wish to explore in this brief paper the possibility of there being …