The host galaxies and possible progenitors of fast radio bursts
thesisposted on 28.03.2022, 11:04 authored by Lachlan Marnoch
Fast radio bursts (FRBs) are millisecond-scale radio pulses from extragalactic sources, the origin of which remains mysterious. This is partially because of the difficulty in localising FRBs to host galaxies, previously achieved only with the repeating source FRB 121102. Now, the Commensal Real-time ASKAP Fast Transients (CRAFT) survey has traced several FRBs to their hosts. These localisations provide the opportunity to study the host galaxies at a range of wavelengths, which will shed light on FRB source environments, and, in the future, the nature of their progenitors. This work focuses on optical follow-up of CRAFT fast radio bursts using Very Large Telescope imaging. Photometric measurements of five host galaxies are performed, and their nature discussed. Four FRB hosts are examined, using the method of direct subtraction of two epochs, for supernova-like optical counterparts to the FRBs. None are identified. Limits are placed on the brightness of any associated transients, and a Monte Carlo approach is used to estimate the probability of a supernova associated with each FRB going undetected. It is found that Type Ia and IIn supernovae are unlikely to accompany all FRBs. Implications for FRB progenitor models are discussed.