2025/11/18 by Minami Nakane, Vasily Kokorev, Nakane, Minami +149 · 1 citation
#astro-ph.GA
paper · pdf · doi:10.48550/arxiv.2511.14483
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 (VENUS). 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 lensing 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\rm UV∼-18.0 mag) resolved into multiple stellar clumps, each of which has an effective radius of reff∼ 10-70 pc and a stellar mass of ∼107 M_\odot. These clumps dominate the stellar mass budget of the Misty Moons (\gtrsim80%), 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\gtrsim10 faint galaxies, such as JADES-GS-z13-0 and JADES-GS-z14-1, indicating that the Misty Moons represents a typical z\gtrsim10 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\gtrsim10.