MG15 - Talk detail

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We examine the relic supernova neutrino spectrum as a probe of the nuclear EoS. The sensitivity to the EoS arises largely from the contribution to neutrino emission from failed supernovae (fSNe). We consider a variety of astrophysical scenarios, which include different progenitor masses for a successful explosion, the cosmological star formation rate, starbursts, quiescent star formation, and the metallicity dependence of the initial mass function. We find that the EoS signature remains robust under a variety of conditions. We demonstrate the viability of future neutrino detectors to distinguish the nuclear EoS via the relic supernova neutrino spectrum.

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We present new calculations of the flux power spectrum of the Lyman-alpha forest in order to investigate the effects of time-dependent dark energy on this statistic. We use a parameterized version of the dark energy equation of state and sample the parameters w0 and wa from the allowed observational values as determined by the Planck Satellite. Each chosen w0, wa pair is then used in a high-resolution large-scale cosmological simulation run with the publicly available SPH code GADGET-2. From each of these simulations we extract synthetic Lyman-alpha forest spectra and calculate the flux power spectrum at several different redshifts. These power spectra are then compared to available observational data.

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The core-cusp problem remains as one of the unresolved challenges between observation and simulations in the standard ΛCDM model for the formation of galaxies. Basically, the problem is that ΛCDM simulations predict that the center of galactic dark matter halos contain a steep power-law mass density profile. However, observations of dwarf galaxies in the Local Group reveal a density profile consistent with a nearly flat distribution of dark matter near the center. A number of solutions to this dilemma have been proposed. We investigate the possibility that the dark matter particles themselves self interact and scatter. The scattering of dark matter particles then can smooth out their profile in high-density regions. We also summarize a theoretical model as to how self-interacting dark matter may arise. We implement this form in simulations of self-interacting dark matter in models for galaxy formation and evolution. Constraints on this form of self-interacting dark matter will be summarized.

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The first detection of gravitational waves a binary neutron star merger GW170817 by the LIGO-Virgo Collaboration has provided fundamental new insights into the astrophysical site for the r process nucleosynthesis and on the nature of dense neutron-star matter. The detected gravitational wave signal depends upon the tidal distortion of the neutron stars as they approach merger. We examine how the detected “chirp” depends the adopted equation of state. This places new constrains on the properties of nuclear matter. The detected evidence of heavy-element nucleosynthesis also provides insight into the nature of the r-process and the fission properties of the heaviest nuclei. Parametrically, one can divide models for the r-process into three scenarios roughly characterized by the number of neutron captures per seed nucleus (n/s). In addition to neutron-star mergers, these include magneto-hydrodynamic jets from supernovae and the neutrino heated wind above the proto neutron star in core-collapse supernovae. Insight from GW170817 allows one to better quantify the relative contributions of each astrophysical site and the fission termination of the r-process.

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