Strong gravitational lensing and microlensing of supernovae

TL;DR

Gravitational lensing and microlensing of supernovae offer new methods for cosmological measurements and astrophysical insights, with upcoming surveys expected to significantly increase discoveries and scientific opportunities.

Contribution

This paper provides an overview of the emerging field of lensed supernovae, highlighting new methods, upcoming survey prospects, and scientific applications.

Findings

Lensed SNe can constrain the Hubble constant via time delays.

Upcoming surveys like LSST will discover many lensed SNe.

Lensed SNe can probe SN progenitors, sizes, and dust properties.

Abstract

Strong gravitational lensing and microlensing of supernovae (SNe) are emerging as a new probe of cosmology and astrophysics in recent years. We provide an overview of this nascent research field, starting with a summary of the first discoveries of strongly lensed SNe. We describe the use of the time delays between multiple SN images as a way to measure cosmological distances and thus constrain cosmological parameters, particularly the Hubble constant, whose value is currently under heated debates. New methods for measuring the time delays in lensed SNe have been developed, and the sample of lensed SNe from the upcoming Rubin Observatory Legacy Survey of Space and Time (LSST) is expected to provide competitive cosmological constraints. Lensed SNe are also powerful astrophysical probes. We review the usage of lensed SNe to constrain SN progenitors, acquire high-z SN spectra through lensing magnifications, infer SN sizes via microlensing, and measure properties of dust in galaxies. The current challenge in the field is the rarity and difficulty in finding lensed SNe. We describe various methods and ongoing efforts to find these spectacular explosions, forecast the properties of the expected sample of lensed SNe from upcoming surveys particularly the LSST, and summarize the observational follow-up requirements to enable the various scientific studies. We anticipate the upcoming years to be exciting with a boom in lensed SN discoveries.