VENUS: A Strongly Lensed Clumpy Galaxy at z ~ 11-12 Behind the Galaxy Cluster MACS J0257.1-2325

October 2026 • 2026ApJ..1010..237N

Authors • Nakane, Minami • Kokorev, Vasily • Fujimoto, Seiji • Ouchi, Masami • McLeod, Derek J. • Golubchik, Miriam • Oguri, Masamune • Zitrin, Adi • Bondestam, Cecilia • Donnan, Callum T. • Brammer, Gabriel • Finkelstein, Steven L. • Willott, Chris • Rihtaršič, Gregor • Desprez, Guillaume • Adamo, Angela • Vanzella, Eros • Bradač, Maruša • Messa, Matteo • Yanagisawa, Hiroto • Sun, Fengwu • Ferguson, Henry C. • Lucas, Ray A. • Coe, Dan • Richard, Johan • Abdurro'uf • Akins, Hollis B. • Allingham, Joseph F. V. • Amorín, Ricardo O. • Asada, Yoshihisa • Atek, Hakim • Bauer, Franz E. • Bezanson, Rachel • Bradley, Larry D. • Chisholm, John • Conselice, Christopher J. • Dayal, Pratika • Dessauges-Zavadsky, Miroslava • Diego, Jose M. • Faisst, Andreas L. • Farley, Gavin • Fei, Qinyue • Frye, Brenda L. • Fudamoto, Yoshinobu • Furtak, Lukas J. • Harikane, Yuichi • Hsiao, Tiger Yu-Yang • Jiménez-Teja, Yolanda • Kartaltepe, Jeyhan S. • Kiyota, Tomokazu • Koekemoer, Anton M. • del P. Lagos, Claudia • Magdis, Georgios E. • Meena, Ashish Kumar • Mowla, Lamiya • Noirot, Gaël • Oesch, Pascal A. • Ono, Yoshiaki • Ortiz, Rafael, III • Pan, Richard • Papovich, Casey • Pierel, Justin D. R. • Ricotti, Massimo • Robbins, Luke • Schaerer, Daniel • Schneider, Raffaella • Treu, Tommaso • Valentino, Francesco • Windhorst, Rogier A. • Bromm, Volker • Egami, Eiichi • González-Otero, Mauro • Kohno, Kotaro • Labbe, Ivo • Matthee, Jorryt • Mun, Marcie • Naidu, Rohan P. • Tripodi, Roberta

Abstract • We present the discovery of a strongly lensed galaxy at z ~ 11--12, dubbed the ``Misty Moons,'' identified in the JWST Treasury Survey, Vast Exploration for Nascent, Unexplored Sources. The Misty Moons is gravitationally lensed by the galaxy cluster MACS J0257.1-2325 at z = 0.505, and has five multiple images suggested by two independent lens models. Two of the five images, ID1 and ID2 (μ ~ 20--30), are very bright (F200W~26 AB mag) and exhibit blue SEDs with prominent Lyα breaks. In the source plane, the Misty Moons is a sub-L^*galaxy (M_UV ~ -18.0 mag) resolved into multiple stellar clumps, each of which has an effective radius of r_eff ~ 10--70 pc and a stellar mass of ~10⁷ M_⊙. These clumps dominate the stellar mass budget of the Misty Moons (≳80%), similar to other high-z clumps, which suggests a highly clustered mode of star formation in the early Universe, unlike seen in local dwarf galaxies. We convolve the source-plane image with the JWST/NIRCam point-spread function to produce a mock NIRCam image of the Misty Moons without lensing magnification and find that the intrinsic galaxy has a radial surface-brightness profile comparable to those of z ≳ 10 faint galaxies, such as JADES-GS-z13-0 and JADES-GS-z14-1, indicating that the Misty Moons represents a typical z ≳ 10 faint galaxy. The Misty Moons, a lensed galaxy with resolved internal structures, provides an ideal laboratory for exploring the early stages of galaxy formation at z ≳ 10.

Links

• ELECTR https://doi.org/10.3847/1538-4357/ae8d09