Uncovering a population of gravitational lens galaxies with magnified standard candle SN Zwicky
A. Goobar, J. Johansson, S. Schulze, Nikki Arendse, Ana Sagués Carracedo, Suhail Dhawan, Edvard Mörtsell, C. Fremling, Lin Yan, D. A. Perley, J. Sollerman, R. Joseph, K-Ryan Hinds, William Meynardie, Igor Andreoni, Eric C. Bellm, J. S. Bloom, Thomas E. Collett, A. J. Drake, M. J. Graham, M. M. Kasliwal, Shri Kulkarni, Cameron Lemon, Adam A. Miller, James D. Neill, J. Nordin, Justin Pierel, Johan Richard, Reed Riddle, M. Rigault, B. Rusholme, Y. Sharma, Robert Stein, Gabrielle Stewart, Alice Townsend, Jozsef Vinko, J. C. Wheeler, Avery Wold
Abstract
Abstract Detecting gravitationally lensed supernovae is among the biggest challenges in astronomy. It involves a combination of two very rare phenomena: catching the transient signal of a stellar explosion in a distant galaxy and observing it through a nearly perfectly aligned foreground galaxy that deflects light towards the observer. Here we describe how high-cadence optical observations with the Zwicky Transient Facility, with its unparalleled large field of view, led to the detection of a multiply imaged type Ia supernova, SN Zwicky, also known as SN 2022qmx. Magnified nearly 25-fold, the system was found thanks to the standard candle nature of type Ia supernovae. High-spatial-resolution imaging with the Keck telescope resolved four images of the supernova with very small angular separation, corresponding to an Einstein radius of only θ E = 0.167″ and almost identical arrival times. The small θ E and faintness of the lensing galaxy are very unusual, highlighting the importance of supernovae to fully characterize the properties of galaxy-scale gravitational lenses, including the impact of galaxy substructures.