LISA data analysis: the search for long-lived gravitational wave signals

Bandopadhyay, Diganta ORCID: 0000-0003-0975-5613 (2025). LISA data analysis: the search for long-lived gravitational wave signals. University of Birmingham. Ph.D.

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Abstract

The detection of gravitational waves from the merger of binary black holes in 2015 opened a new window into the universe, and the Laser Interferometer Space Antenna will once again revolutionize our understanding of the cosmos by unveiling the low-frequency gravitational wave universe. Among the many unique challenges that LISA presents, this thesis focuses on the several distinct challenges within the field of LISA data analysis. One of the most demanding aspects is the search for long-lived gravitational wave signals, expected from stellar-mass binary inspirals and extreme-mass ratio inspirals. These signals are expected to be much quieter than the noise in the LISA data and persist in the datastream for a significant fraction of the mission lifetime.

This thesis follows the development of a novel semi-coherent search strategy for stellar-mass binary inspiral signals in LISA data. This search method is initially developed in a simplified form, searching for single signals within noiseless data. Subsequently, the method is extended to search for multiple signals in the presence of noise, and is successfully applied to a LISA data challenge which contains several simulated stellar-mass binary signals. A complementary framework is developed to estimate the significance of each candidate signal, this is used to determine an approximate signal-to-noise ratio threshold for the search.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):