The open-access journal Living Reviews in Relativity has published two new review articles on 6 December 2021:
Aggarwal, N., Aguiar, O.D., Bauswein, A. et al.
Challenges and opportunities of gravitational-wave searches at MHz to GHz frequencies.
Living Rev Relativ 24, 4 (2021).
https://doi.org/10.1007/s41114-021-00032-5
Summary: This white paper outlines the challenges and gains expected in gravitational-wave searches at frequencies above the LIGO/Virgo band, with a particular focus on Ultra High-Frequency Gravitational Waves (UHF-GWs), covering the MHz to GHz range. We highlight some of the most promising gravitational sources, review several detector concepts, and compare their expected sensitivity with the signal strength predicted in various models.
Kyutoku, K., Shibata, M. and Taniguchi, K.
Coalescence of black hole-neutron star binaries.
Living Rev Relativ 24, 5 (2021).
https://doi.org/10.1007/s41114-021-00033-4
(This article is a revised version of https://doi.org/10.12942/lrr-2011-6.)
Summary: We review the current status of general relativistic studies for coalescences of black hole-neutron star binaries. We summarize our understanding for the merger process, tidal disruption and its criterion, properties of the merger remnant and ejected material, gravitational waveforms, and gravitational-wave spectra. We also discuss expected electromagnetic counterparts to black hole-neutron star coalescences.