세종대학교 두드림 비교과통합관리시스템

물리천문학과 콜로퀴움

‧강연 제목 : Probing the Universe with Multi-Messenger Astronomy 

‧연사 : 서울대학교 이형목 교수님 

‧일시 : 2023년 11월 29일 (수요일) 17:00~18:30

‧진행 방법 : 영실관 601호

‧신청 가능 대상 : 세종대학교 재학생 누구나

‧신청기간 : 11월 22일 ~ 11월29일

‧강의 초록

Distances to merging binary systems can be estimated by analyzing gravitational wave (GW) data, bypassing the need for cumbersome calibration processes. To further harness GWs in constructing the universe's expansion history, it's crucial to obtain redshift data for these sources by identifying their host galaxies, possibly through multi-messenger observations. The accuracy of the Hubble constant, based on the only gravitational source GW170817 with an identified host galaxy through multi-messenger observations, suffers from significant statistical errors due to the distance-inclination angle degeneracy. Gravitational wave sources lacking electromagnetic counterparts are known as dark sirens, and identifying their host galaxies is challenging due to the relatively poor positional accuracy of these sources observed by ground-based detectors. Significant improvements become possible when detectors sensitive to mid-frequencies in the range of 0.01 to 10 Hz are used, as they allow for longer-duration observations of many black hole and neutron star binaries. We discuss the improvements in the accuracy of sky positions and luminosity distances for the population of compact binary coalescences inferred from GWTC-3 data. Our findings demonstrate that, with proposed detectors like AEDGE and DECIGO, the host galaxies of some of these sources can be uniquely identified without relying on electromagnetic radiation. The presence of orbital eccentricity at around 0.1 Hz can further enhance the precision of position and distance estimation. It may be possible to uniquely identify certain dark sirens up to a redshift of 0.1 or beyond, even with the early versions of the proposed mid-frequency detectors.