Detecting the gravitational wave memory effect with TianQin

Abstract

The memory effect in gravitational waves is a direct prediction of general relativity. The presence of the memory effect in gravitational wave signals not only serves as a test for general relativity but also establishes connections between soft theorem, and asymptotic symmetries, serving as a bridge for exploring fundamental physics. Furthermore, with the ongoing progress in space-based gravitational wave detection projects, the gravitational wave memory effect generated by the merger of massive binary black hole binaries is becoming increasingly significant and cannot be ignored. In this work, we perform the full Bayesian analysis of the gravitational wave memory effect with TianQin. The results indicate that the memory effect has a certain impact on parameter estimation but does not deviate beyond the 1σ range. Additionally, the Bayes factor analysis suggests that when the signal-to-noise ratio of the memory effect in TianQin is approximately 2.36, the log 10 Bayes factor reaches 8. This result is consistent with the findings obtained from a previous mismatch threshold.

Measuring the Hubble constant using strongly lensed gravitational wave signals

“…We evaluate the potential of this new method in measuring the Hubble constant and provide preliminary results for TianQin, which is a planned space-based GW observatory sensitive to the millihertz band [35]. In recent years, a significant amount of effort has been put into the study and consolidation of the science cases for TianQin [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. For the detected GW sources, TianQin's sky localization precision can reach the level of 1 deg 2 to 0.1 deg 2 [37,[41][42][43], which makes it possible to combine subsequent EM observations to implement multi-messenger astronomy.…”

Unifying ordinary and null memory

“…Excitingly, the first detection of the gravitational wave memory effect is soon to be expected [31,[48][49][50][51][52][53][54][55][56][57][58][59][60][61], at the very least with next-generation ground based detectors such as the Einstein Telescope [62,63] or Cosmic Explorer [64,65], as well as with the Laser Interferometer Space Antenna (LISA) mission [66]. This in particular also motivates the search for a deeper understanding of memory beyond GR to harvest the full potential of gravitational memory in probing the theory of gravity and its implications on the fabric of spacetime.…”

Memory effect of gravitational wave pulses in PP-wave spacetimes

“…It is a strong-field effect of gravity that has remained undetected in astrophysical observations till today [11,12]. Because of the inherent weakness of GWs, the permanent changes in the displacement and in the time delays in various detector-dependent setup are too small for the available technologies to directly measure them [13]. However, these changes may become observable in the current and planned detectors in the near future [14][15][16][17], provided that their low-frequency sensitivity can be increased further [18].…”

“…The article [19] explores the possibility of the detection of non-linear memory by the ALIGO and Virgo detectors. The authors in [13,20] have suggested different methods of detection using space-based detectors. Some of the earlier works, such as [4] and [8], have discussed the experimental prospects for detecting the memories of GW bursts.…”