Abstract

Strongly lensed supernovae are excellent, independent probes to measure the Hubble constant and weigh in on the Hubble tension. In my talk I will discuss the time delay measurements for the first resolved strongly lensed Type Ia supernova, iPTF16geu and the discovery of the first lensed SN with the Zwicky Transient Facility, SN Zwicky. I will review ongoing spectroscopic analysis of SN Zwicky, to test – with high-fidelity data – whether high-redshift SNe Ia are similar to their near universe counterparts, an important systematic for dark energy inference. With JWST , we can feasibly obtain NIR spectra in the nebular phase to study the presence of stable elements in the ejecta and therefore, understand the progenitors of SNe Ia. In the LSST era, we expect tens of lensed SNe per year. In this talk, I will summarise ongoing work on the impact of the survey cadence and systematics on the lensed SN discovery rate.