Discovery of SN 2025wny: a Strongly Gravitationally Lensed Superluminous Supernova at z = 2.01

Joel Johansson; Daniel A. Perley; Ariel Goobar; Jacob L. Wise; Yu-Jing Qin; Zoë McGrath; Steve Schulze; Cameron Lemon; Anjasha Gangopadhyay; Konstantinos Tsalapatas; Igor Andreoni; Eric C. Bellm; Joshua S. Bloom; Richard Dekany; Suhail Dhawan; Christoffer Fremling; Matthew J. Graham; Steven L. Groom; Daniel Gruen; Xander J. Hall; Mansi Kasliwal; Russ R. Laher; Ragnhild Lunnan; Ashish A. Mahabal; Adam A. Miller; Edvard Mörtsell; Jakob Nordin; Jacob Osman Hjortlund; R. Michael Rich; Reed L. Riddle; Avinash Singh; Jesper Sollerman; Alice Townsend; Lin Yan

arXiv · 2510.23533

Discovery of SN 2025wny: a Strongly Gravitationally Lensed Superluminous Supernova at z = 2.01

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Abstract

We present the discovery of SN 2025wny (ZTF25abnjznp/GOTO25gtq) and spectroscopic classification of this event as the first gravitationally lensed Type I superluminous supernovae (SLSN-I). Deep ground-based follow-up observations resolves four images of the supernova with ~1.7" angular separation from the main lens galaxy, each coincident with the lensed images of a background galaxy seen in archival imaging of the field. Spectroscopy of the brightest point image shows narrow features matching absorption lines at a redshift of z = 2.011 and broad features matching those seen in superluminous SNe with Far-UV coverage. We infer a magnification factor of 20 to 50 for the brightest image in the system, based on photometric and spectroscopic comparisons to other SLSNe-I. SN 2025wny demonstrates that gravitationally-lensed SNe are in reach of ground-based facilities out to redshifts far higher than what has been previously assumed, and provide a unique window into studying distant supernovae, internal properties of dwarf galaxies, as well as for time-delay cosmography.

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Joel Johansson, Daniel A. Perley, Ariel Goobar, Jacob L. Wise, Yu-Jing Qin, Zoë McGrath, Steve Schulze, Cameron Lemon, Anjasha Gangopadhyay, Konstantinos Tsalapatas, Igor Andreoni, Eric C. Bellm, Joshua S. Bloom, Richard Dekany, Suhail Dhawan, Christoffer Fremling, Matthew J. Graham, Steven L. Groom, Daniel Gruen, Xander J. Hall, Mansi Kasliwal, Russ R. Laher, Ragnhild Lunnan, Ashish A. Mahabal, Adam A. Miller, Edvard Mörtsell, Jakob Nordin, Jacob Osman Hjortlund, R. Michael Rich, Reed L. Riddle, Avinash Singh, Jesper Sollerman, Alice Townsend, Lin Yan. 2025-10-27. Discovery of SN 2025wny: a Strongly Gravitationally Lensed Superluminous Supernova at z = 2.01. https://arxiv.org/abs/2510.23533

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