Theoretical astrophysics and plasma physics at RPC

Abstract:

The localization of stellar-mass binary black hole mergers using gravitational waves is critical in understanding the properties of the binaries' host galaxies, observing possible electromagnetic emission from the mergers, or using them as a cosmological distance ladder. The precision of this localization can be substantially increased with prior astrophysical information about the binary system. In particular, constraining the inclination of the binary can reduce the distance uncertainty of the source. Here we present the first realistic set of localizations for binary black hole mergers, including different prior constraints on the binaries' inclinations. We find that prior information on the inclination can reduce the localization volume by a factor of 3. We discuss two astrophysical scenarios of interest: (i) follow-up searches for beamed electromagnetic/neutrino counterparts and (ii) mergers in the accretion disks of active galactic nuclei.

Abstract:

This article discusses the dual use of digital image correlation and thermoelastic stress analyses for the study of propagating cracks. It is shown that a few critical parameters such as emissivity and the thermoelastic constant required for the latter can be calibrated with the former. A unified framework is introduced, which treats both experimental techniques equally to locate crack tips, and then evaluate stress intensity factors. This framework allows for a detailed and quantitative comparison between both methods. It is found that, for the case at hand, the thermoelastic stress analyses outputs were less noise sensitive while the digital image correlation method was less dependent on calibration. The proposed procedure was very robust for finding the crack tip location for both experimental methods.