Uncovering a population of gravitational lens galaxies with magnified standard candle SN Zwicky
Richard, Johan; Riddle, Reed; Wheeler, J. Craig; Rusholme, Ben; Sollerman, Jesper; Joseph, Rémy; Stein, Robert; Andreoni, Igor; Fremling, Christoffer; Miller, Adam A.; Nordin, Jakob; Sharma, Yashvi; Arendse, Nikki; Perley, Daniel; Neill, James D.; Schulze, Steve; Collett, Thomas E.; Graham, Matthew; Wold, Avery; Vinko, Jozsef; Yan, Lin; Drake, Andrew; Rigault, Mickael; Pierel, Justin; Bellm, Eric; Carracedo, Ana Sagués; Dhawan, Suhail; Goobar, Ariel; Mörtsell, Edvard; Johansson, Joel; Hinds, K. -Ryan; Kasliwal, Mansi; Kulkarni, Shri R.; Lemon, Cameron; Meynardie, William; Bloom, Josh; Stewart, Gabrielle; Townsend, Alice
Sweden, United Kingdom, United States, Switzerland, Germany, France, Hungary
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 θe = 0.167" and almost identical arrival times. The small θE 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.