Strongly lensed supernovae: lessons learned

TL;DR

This paper reviews the recent progress in discovering and studying strongly lensed supernovae, highlighting their importance for cosmology and lensing galaxy properties, based on space and ground-based observations.

Contribution

It provides a comprehensive overview of the challenges and opportunities in identifying and utilizing strongly lensed supernovae for scientific insights.

Findings

Space-based detection of distant, faint supernovae

Ground-based identification of bright, compact lensed supernovae

Potential for using supernovae in time-delay cosmography

Abstract

Since about a decade, we have finally entered the era of discoveries of multiply-imaged gravitationally lensed supernovae. To date, all cluster lensed supernovae, very distant, faint and spatially resolved, have been found from space. In contrast, those deflected by individual galaxies have been very compact and bright enough to be identified with wide-field ground-based surveys through the magnification of "standard candles" method, i.e., without the need of spatially resolving the individual images. We review the challenges in identifying these extremely rare events, as well as the unique opportunities they offer for two major applications: time-delay cosmography and the study of the properties of the deflecting bodies acting as lenses.