Targeted subthreshold search for strongly lensed gravitational-wave events

Creators: Li, Alvin K. Y.; Lo, Rico K. L.¹; Sachdev, Surabhi; Chan, Juno C. L.; Lin, E. T.; Li, Tjonnie G. F.; Weinstein, Alan J.¹

1. California Institute of Technology

Abstract

Strong gravitational lensing of gravitational waves can produce duplicate signals separated in time with different amplitudes. We consider the case in which strong lensing produces superthreshold gravitational-wave events and weaker subthreshold signals buried in the noise background. We present the gstlal-based TargetEd Subthreshold Lensing seArch search method for the subthreshold signals using reduced template banks targeting specific confirmed gravitational-wave events. We perform a simulation campaign to assess the performance of the proposed search method. We show that it can effectively uprank potential subthreshold lensed counterparts to the target gravitational-wave event. We also compare its performance to other alternative solutions to the posed problem and demonstrate that our proposed method outperforms the other solutions. The method described in this paper has already been deployed in the recent LVK Collaboration-wide search for lensing signatures of gravitational waves in the first half of LIGO/Virgo third observing run O3a [R. Abbott et al. (LIGO Scientific, Virgo Collaborations), Astrophys. J. 923, 14 (2021).].

Copyright and License

Acknowledgement

The authors acknowledge the generous support from the National Science Foundation in the United States. The authors would also like to acknowledge Jonah Kanner and Bruce Allen for their useful suggestions. R. K. L. L. and T. G. F. L. would also like to gratefully acknowledge the support from the Croucher Foundation in Hong Kong. The work described in this paper was partially supported by a grant from the Research Grants Council of the Hong Kong (Project No. CUHK 14306218) and the Direct Grant for Research from the Research Committee of the Chinese University of Hong Kong. S. S. was supported in part by the LIGO Laboratory and in part by the Eberly Research Funds of Penn State, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. J. C. L. C. acknowledges support from the Villum Investigator program supported by VILLUM FONDEN (Grant No. 37766) and the DNRF Chair, by the Danish Research Foundation. The authors are also grateful for computational resources provided by the LIGO Laboratory and supported by National Science Foundation Grants No. PHY-0757058 and No. PHY-0823459. This research has made use of data, software and/or web tools obtained from the Gravitational Wave Open Science Center [95,96], a service of LIGO Laboratory, the LIGO Scientific Collaboration and the Virgo Collaboration. LIGO was constructed by the California Institute of Technology and Massachusetts Institute of Technology with funding from the National Science Foundation and operates under cooperative Agreement No. PHY-0757058. Virgo is funded by the French Centre National de Recherche Scientifique (CNRS), the Italian Istituto Nazionale della Fisica Nucleare (INFN) and the Dutch Nikhef, with contributions by Polish and Hungarian institutes. This paper carries LIGO Document No. LIGO-P1900059. A. K. Y. L. and R. K. L. L. would like to gratefully acknowledge the support from the National Science Foundation through the Grants NSF PHY-1912594 and NSF PHY-2207758.

Files

PhysRevD.107.123014.pdf

Files (2.3 MB)

Name	Size	Download all
PhysRevD.107.123014.pdf md5:e239ba976b56357607edfa5ef42e637b	2.3 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes