Utilizing the Moon as antenna for gravitational waves

Abstract: Since 2015, we have been observing the dark side of the universe with gravitational-wave (GW) detectors. As amazing as the Virgo and LIGO instruments and their first observations are, they are only the very first step into the new era of GW science and astronomy. The prospect to detect signals from kilometer-scale sources out to redshifts of 100 with the proposed Einstein Telescope and Cosmic Explorer, or the merger of supermassive black holes with pulsar-timing arrays and the approved LISA mission is mind-boggling. These detectors are part of a wider effort to expand gravitational-wave observations, and they leave open the decihertz band, which harbors many interesting sources of GWs. In this talk, we will present the Lunar GW Antenna (LGWA), which was proposed in 2020 to observe GWs on the Moon also in the decihertz band. It exploits the Moon itself as a giant antenna for GWs. Its pathfinder mission Soundcheck was recently selected by ESA into the Reserve Pool of Science Activities for the Moon. Its goal is to characterize the geophysical environment of a permanently shadowed region at one of the lunar poles.