A Natural ≳100× Telescope: Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37

Cameron Lemon; Ariel Goobar; Joel Johansson; Edvard Mörtsell; Steve Schulze; Igor Andreoni; Aleksandra Bochenek; Seán J. Brennan; Malte Busmann; Michael Coughlin; Kaustav K. Das; Suhail Dhawan; Christoffer Fremling; Anjasha Gangopadhyay; Daniel Gruen; Xander J. Hall; Anna Y.Q. Ho; Mansi M. Kasliwal; Daniel A. Perley; Mickael Rigault; Genevieve Schroeder; Mathew Smith; Jesper Sollerman; Jean J. Somalwar; Robert Stein; Stephen Thorp; Alice Townsend; Jacob L. Wise; Lin Yan; Nikki Arendse; Eric C. Bellm; Tracy X. Chen; Andrew Drake; Frank J. Masci; Josiah Purdum; Roger Smith; Jason T. Hinkle; T. Emil Rivera-Thorsen; Benjamin J. Shappee; Michael A. Tucker; Jessica Aguilar; Steven Ahlen; Greg Aldering; Segev BenZvi; Davide Bianchi; David Brooks; Todd Claybaugh; Axel de la Macorra; John Della Costa; Arjun Dey; Peter Doel; Brenna Flaugher; Andreu Font-Ribera; Jaime E. Forero-Romero; Enrique Gaztañaga; Satya Gontcho A. Gontcho; Gaston Gutierrez; Dragan Huterer; Mustapha Ishak; Jorge Jimenez; Dick Joyce; Stephanie Juneau; Robert Kehoe; Alex G. Kim; David Kirkby; Theodore Kisner; Anthony Kremin; Ofer Lahav; Martin Landriau; Laurent Le Guillou; Michael E. Levi; Marc Manera; Aaron Meisner; Ramon Miquel; John Moustakas; Seshadri Nadathur; Brendan O’Connor; Nathalie Palanque-Delabrouille; Antonella Palmese; Will J. Percival; Ignasi Pérez-Ràfols; Claire Poppett; Francisco Prada; Graziano Rossi; Eusebio Sanchez; David Schlegel; Michael Schubnell; Arman Shafieloo; Joseph Silber; David Sprayberry; Gregory Tarlé; Benjamin A. Weaver; Hu Zou

doi:10.3847/2041-8213/ae6780

A Natural ≳100× Telescope: Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37

Cameron Lemon
, Ariel Goobar
, Joel Johansson
, Edvard Mörtsell
, Steve Schulze
, Igor Andreoni
, Aleksandra Bochenek
, Seán J. Brennan
, Malte Busmann
, Michael Coughlin
, Kaustav K. Das
, Suhail Dhawan
, Christoffer Fremling
, Anjasha Gangopadhyay
, Daniel Gruen
, Xander J. Hall
, Anna Y.Q. Ho
, Mansi M. Kasliwal
, Daniel A. Perley
, Mickael Rigault

Genevieve Schroeder, Mathew Smith, Jesper Sollerman, Jean J. Somalwar, Robert Stein, Stephen Thorp, Alice Townsend, Jacob L. Wise, Lin Yan, Nikki Arendse, Eric C. Bellm, Tracy X. Chen, Andrew Drake, Frank J. Masci, Josiah Purdum, Roger Smith, Jason T. Hinkle, T. Emil Rivera-Thorsen, Benjamin J. Shappee, Michael A. Tucker, Jessica Aguilar, Steven Ahlen, Greg Aldering, Segev BenZvi, Davide Bianchi, David Brooks, Todd Claybaugh, Axel de la Macorra, John Della Costa, Arjun Dey, Peter Doel, Brenna Flaugher, Andreu Font-Ribera, Jaime E. Forero-Romero, Enrique Gaztañaga, Satya Gontcho A. Gontcho, Gaston Gutierrez, Dragan Huterer, Mustapha Ishak, Jorge Jimenez, Dick Joyce, Stephanie Juneau, Robert Kehoe, Alex G. Kim, David Kirkby, Theodore Kisner, Anthony Kremin, Ofer Lahav, Martin Landriau, Laurent Le Guillou, Michael E. Levi, Marc Manera, Aaron Meisner, Ramon Miquel, John Moustakas, Seshadri Nadathur, Brendan O’Connor, Nathalie Palanque-Delabrouille, Antonella Palmese, Will J. Percival, Ignasi Pérez-Ràfols, Claire Poppett, Francisco Prada, Graziano Rossi, Eusebio Sanchez, David Schlegel, Michael Schubnell, Arman Shafieloo, Joseph Silber, David Sprayberry, Gregory Tarlé, Benjamin A. Weaver, Hu Zou

Physics and Astronomy (Twin Cities)

Research output: Contribution to journal › Article › peer-review

Abstract

We present the discovery of SN 2025mkn, a gravitationally lensed Type II supernova. First detected as a blue transient in Zwicky Transient Facility (ZTF), 0 (Formula presented) .″ 83 from a z = 0.42 elliptical galaxy, the follow-up SNIFS/UH2.2 m and LRIS/Keck spectra revealed absorption lines at z = 1.371. Later JWST NIRCam imaging shows that the bright transient is a close pair of point sources separated by (Formula presented) ∼0.″07, and a 30 times fainter counterimage opposite the lens, for which NIRSpec reveals strong Hα emission also at z = 1.371. The lightcurves and spectra are consistent with the Type II supernova source being magnified ≳100 times, with ∼250 required to reconcile its luminosity with that of nearby events such as SN 2023ixf. Lens models are consistent with such high magnifications, and always show that the faint image arrived first (undetected in earlier ZTF imaging), consistent with the later spectral phase of this fainter image. A fourth image is also predicted and possibly detected in the NIRSpec data. Lightcurve-based time-delay measurements are not possible due to the first image being the faintest; however, the resolved NIRSpec spectra offer a future opportunity for time-delay cosmography through supernova phase measurements.

Original language	English (US)
Article number	L47
Journal	Astrophysical Journal Letters
Volume	1003
Issue number	2
DOIs	https://doi.org/10.3847/2041-8213/ae6780
State	Published - Jun 1 2026

Bibliographical note

Publisher Copyright:
© 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Keywords

Strong gravitational lensing (1643)
Supernovae (1668)
Type II supernovae (1731)

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10.3847/2041-8213/ae6780

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Lemon, C., Goobar, A., Johansson, J., Mörtsell, E., Schulze, S., Andreoni, I., Bochenek, A., Brennan, S. J., Busmann, M., Coughlin, M., Das, K. K., Dhawan, S., Fremling, C., Gangopadhyay, A., Gruen, D., Hall, X. J., Ho, A. Y. Q., Kasliwal, M. M., Perley, D. A., ... Zou, H. (2026). A Natural ≳100× Telescope: Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37. Astrophysical Journal Letters, 1003(2), Article L47. https://doi.org/10.3847/2041-8213/ae6780

Lemon, C, Goobar, A, Johansson, J, Mörtsell, E, Schulze, S, Andreoni, I, Bochenek, A, Brennan, SJ, Busmann, M, Coughlin, M, Das, KK, Dhawan, S, Fremling, C, Gangopadhyay, A, Gruen, D, Hall, XJ, Ho, AYQ, Kasliwal, MM, Perley, DA, Rigault, M, Schroeder, G, Smith, M, Sollerman, J, Somalwar, JJ, Stein, R, Thorp, S, Townsend, A, Wise, JL, Yan, L, Arendse, N, Bellm, EC, Chen, TX, Drake, A, Masci, FJ, Purdum, J, Smith, R, Hinkle, JT, Rivera-Thorsen, TE, Shappee, BJ, Tucker, MA, Aguilar, J, Ahlen, S, Aldering, G, BenZvi, S, Bianchi, D, Brooks, D, Claybaugh, T, de la Macorra, A, Della Costa, J, Dey, A, Doel, P, Flaugher, B, Font-Ribera, A, Forero-Romero, JE, Gaztañaga, E, Gontcho A. Gontcho, S, Gutierrez, G, Huterer, D, Ishak, M, Jimenez, J, Joyce, D, Juneau, S, Kehoe, R, Kim, AG, Kirkby, D, Kisner, T, Kremin, A, Lahav, O, Landriau, M, Le Guillou, L, Levi, ME, Manera, M, Meisner, A, Miquel, R, Moustakas, J, Nadathur, S, O’Connor, B, Palanque-Delabrouille, N, Palmese, A, Percival, WJ, Pérez-Ràfols, I, Poppett, C, Prada, F, Rossi, G, Sanchez, E, Schlegel, D, Schubnell, M, Shafieloo, A, Silber, J, Sprayberry, D, Tarlé, G, Weaver, BA & Zou, H 2026, 'A Natural ≳100× Telescope: Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37', Astrophysical Journal Letters, vol. 1003, no. 2, L47. https://doi.org/10.3847/2041-8213/ae6780

@article{7ca2f62c0fb4417ca4b5d460e6c3acd2,

title = "A Natural ≳100{\texttimes} Telescope: Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37",

abstract = "We present the discovery of SN 2025mkn, a gravitationally lensed Type II supernova. First detected as a blue transient in Zwicky Transient Facility (ZTF), 0 (Formula presented) .″ 83 from a z = 0.42 elliptical galaxy, the follow-up SNIFS/UH2.2 m and LRIS/Keck spectra revealed absorption lines at z = 1.371. Later JWST NIRCam imaging shows that the bright transient is a close pair of point sources separated by (Formula presented) ∼0.″07, and a 30 times fainter counterimage opposite the lens, for which NIRSpec reveals strong Hα emission also at z = 1.371. The lightcurves and spectra are consistent with the Type II supernova source being magnified ≳100 times, with ∼250 required to reconcile its luminosity with that of nearby events such as SN 2023ixf. Lens models are consistent with such high magnifications, and always show that the faint image arrived first (undetected in earlier ZTF imaging), consistent with the later spectral phase of this fainter image. A fourth image is also predicted and possibly detected in the NIRSpec data. Lightcurve-based time-delay measurements are not possible due to the first image being the faintest; however, the resolved NIRSpec spectra offer a future opportunity for time-delay cosmography through supernova phase measurements.",

keywords = "Strong gravitational lensing (1643), Supernovae (1668), Type II supernovae (1731)",

author = "Cameron Lemon and Ariel Goobar and Joel Johansson and Edvard M{\"o}rtsell and Steve Schulze and Igor Andreoni and Aleksandra Bochenek and Brennan, \{Se{\'a}n J.\} and Malte Busmann and Michael Coughlin and Das, \{Kaustav K.\} and Suhail Dhawan and Christoffer Fremling and Anjasha Gangopadhyay and Daniel Gruen and Hall, \{Xander J.\} and Ho, \{Anna Y.Q.\} and Kasliwal, \{Mansi M.\} and Perley, \{Daniel A.\} and Mickael Rigault and Genevieve Schroeder and Mathew Smith and Jesper Sollerman and Somalwar, \{Jean J.\} and Robert Stein and Stephen Thorp and Alice Townsend and Wise, \{Jacob L.\} and Lin Yan and Nikki Arendse and Bellm, \{Eric C.\} and Chen, \{Tracy X.\} and Andrew Drake and Masci, \{Frank J.\} and Josiah Purdum and Roger Smith and Hinkle, \{Jason T.\} and Rivera-Thorsen, \{T. Emil\} and Shappee, \{Benjamin J.\} and Tucker, \{Michael A.\} and Jessica Aguilar and Steven Ahlen and Greg Aldering and Segev BenZvi and Davide Bianchi and David Brooks and Todd Claybaugh and \{de la Macorra\}, Axel and \{Della Costa\}, John and Arjun Dey and Peter Doel and Brenna Flaugher and Andreu Font-Ribera and Forero-Romero, \{Jaime E.\} and Enrique Gazta{\~n}aga and \{Gontcho A. Gontcho\}, Satya and Gaston Gutierrez and Dragan Huterer and Mustapha Ishak and Jorge Jimenez and Dick Joyce and Stephanie Juneau and Robert Kehoe and Kim, \{Alex G.\} and David Kirkby and Theodore Kisner and Anthony Kremin and Ofer Lahav and Martin Landriau and \{Le Guillou\}, Laurent and Levi, \{Michael E.\} and Marc Manera and Aaron Meisner and Ramon Miquel and John Moustakas and Seshadri Nadathur and Brendan O{\textquoteright}Connor and Nathalie Palanque-Delabrouille and Antonella Palmese and Percival, \{Will J.\} and Ignasi P{\'e}rez-R{\`a}fols and Claire Poppett and Francisco Prada and Graziano Rossi and Eusebio Sanchez and David Schlegel and Michael Schubnell and Arman Shafieloo and Joseph Silber and David Sprayberry and Gregory Tarl{\'e} and Weaver, \{Benjamin A.\} and Hu Zou",

note = "Publisher Copyright: {\textcopyright} 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.",

year = "2026",

month = jun,

day = "1",

doi = "10.3847/2041-8213/ae6780",

language = "English (US)",

volume = "1003",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "American Astronomical Society",

number = "2",

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TY - JOUR

T1 - A Natural ≳100× Telescope

T2 - Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37

AU - Lemon, Cameron

AU - Goobar, Ariel

AU - Johansson, Joel

AU - Mörtsell, Edvard

AU - Schulze, Steve

AU - Andreoni, Igor

AU - Bochenek, Aleksandra

AU - Brennan, Seán J.

AU - Busmann, Malte

AU - Coughlin, Michael

AU - Das, Kaustav K.

AU - Dhawan, Suhail

AU - Fremling, Christoffer

AU - Gangopadhyay, Anjasha

AU - Gruen, Daniel

AU - Hall, Xander J.

AU - Ho, Anna Y.Q.

AU - Kasliwal, Mansi M.

AU - Perley, Daniel A.

AU - Rigault, Mickael

AU - Schroeder, Genevieve

AU - Smith, Mathew

AU - Sollerman, Jesper

AU - Somalwar, Jean J.

AU - Stein, Robert

AU - Thorp, Stephen

AU - Townsend, Alice

AU - Wise, Jacob L.

AU - Yan, Lin

AU - Arendse, Nikki

AU - Bellm, Eric C.

AU - Chen, Tracy X.

AU - Drake, Andrew

AU - Masci, Frank J.

AU - Purdum, Josiah

AU - Smith, Roger

AU - Hinkle, Jason T.

AU - Rivera-Thorsen, T. Emil

AU - Shappee, Benjamin J.

AU - Tucker, Michael A.

AU - Aguilar, Jessica

AU - Ahlen, Steven

AU - Aldering, Greg

AU - BenZvi, Segev

AU - Bianchi, Davide

AU - Brooks, David

AU - Claybaugh, Todd

AU - de la Macorra, Axel

AU - Della Costa, John

AU - Dey, Arjun

AU - Doel, Peter

AU - Flaugher, Brenna

AU - Font-Ribera, Andreu

AU - Forero-Romero, Jaime E.

AU - Gaztañaga, Enrique

AU - Gontcho A. Gontcho, Satya

AU - Gutierrez, Gaston

AU - Huterer, Dragan

AU - Ishak, Mustapha

AU - Jimenez, Jorge

AU - Joyce, Dick

AU - Juneau, Stephanie

AU - Kehoe, Robert

AU - Kim, Alex G.

AU - Kirkby, David

AU - Kisner, Theodore

AU - Kremin, Anthony

AU - Lahav, Ofer

AU - Landriau, Martin

AU - Le Guillou, Laurent

AU - Levi, Michael E.

AU - Manera, Marc

AU - Meisner, Aaron

AU - Miquel, Ramon

AU - Moustakas, John

AU - Nadathur, Seshadri

AU - O’Connor, Brendan

AU - Palanque-Delabrouille, Nathalie

AU - Palmese, Antonella

AU - Percival, Will J.

AU - Pérez-Ràfols, Ignasi

AU - Poppett, Claire

AU - Prada, Francisco

AU - Rossi, Graziano

AU - Sanchez, Eusebio

AU - Schlegel, David

AU - Schubnell, Michael

AU - Shafieloo, Arman

AU - Silber, Joseph

AU - Sprayberry, David

AU - Tarlé, Gregory

AU - Weaver, Benjamin A.

AU - Zou, Hu

N1 - Publisher Copyright: © 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

PY - 2026/6/1

Y1 - 2026/6/1

N2 - We present the discovery of SN 2025mkn, a gravitationally lensed Type II supernova. First detected as a blue transient in Zwicky Transient Facility (ZTF), 0 (Formula presented) .″ 83 from a z = 0.42 elliptical galaxy, the follow-up SNIFS/UH2.2 m and LRIS/Keck spectra revealed absorption lines at z = 1.371. Later JWST NIRCam imaging shows that the bright transient is a close pair of point sources separated by (Formula presented) ∼0.″07, and a 30 times fainter counterimage opposite the lens, for which NIRSpec reveals strong Hα emission also at z = 1.371. The lightcurves and spectra are consistent with the Type II supernova source being magnified ≳100 times, with ∼250 required to reconcile its luminosity with that of nearby events such as SN 2023ixf. Lens models are consistent with such high magnifications, and always show that the faint image arrived first (undetected in earlier ZTF imaging), consistent with the later spectral phase of this fainter image. A fourth image is also predicted and possibly detected in the NIRSpec data. Lightcurve-based time-delay measurements are not possible due to the first image being the faintest; however, the resolved NIRSpec spectra offer a future opportunity for time-delay cosmography through supernova phase measurements.

AB - We present the discovery of SN 2025mkn, a gravitationally lensed Type II supernova. First detected as a blue transient in Zwicky Transient Facility (ZTF), 0 (Formula presented) .″ 83 from a z = 0.42 elliptical galaxy, the follow-up SNIFS/UH2.2 m and LRIS/Keck spectra revealed absorption lines at z = 1.371. Later JWST NIRCam imaging shows that the bright transient is a close pair of point sources separated by (Formula presented) ∼0.″07, and a 30 times fainter counterimage opposite the lens, for which NIRSpec reveals strong Hα emission also at z = 1.371. The lightcurves and spectra are consistent with the Type II supernova source being magnified ≳100 times, with ∼250 required to reconcile its luminosity with that of nearby events such as SN 2023ixf. Lens models are consistent with such high magnifications, and always show that the faint image arrived first (undetected in earlier ZTF imaging), consistent with the later spectral phase of this fainter image. A fourth image is also predicted and possibly detected in the NIRSpec data. Lightcurve-based time-delay measurements are not possible due to the first image being the faintest; however, the resolved NIRSpec spectra offer a future opportunity for time-delay cosmography through supernova phase measurements.

KW - Strong gravitational lensing (1643)

KW - Supernovae (1668)

KW - Type II supernovae (1731)

UR - https://www.scopus.com/pages/publications/105041085694

UR - https://www.scopus.com/pages/publications/105041085694#tab=citedBy

U2 - 10.3847/2041-8213/ae6780

DO - 10.3847/2041-8213/ae6780

M3 - Article

AN - SCOPUS:105041085694

SN - 2041-8205

VL - 1003

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 2

M1 - L47

ER -

A Natural ≳100× Telescope: Discovery of the Strongly Lensed Type II SN 2025mkn at z = 1.37

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