Unveiling the Cosmic Gems Arc at z  ∼ 10 with JWST NIRCam

作者：Larry Bradley, Angela Adamo, E. Vanzella, Keren Sharon, Gabriel Brammer, Dan Coe, J. M. Diego, Vasily Kokorev, Guillaume Mahler, Masamune Oguri, Abdurrouf, Rachana Bhatawdekar, L. Christensen, Seiji Fujimoto, Takuya Hashimoto, Tiger Yu-Yang Hsiao, Akio Inoue, Yolanda Jiménez-Teja, Matteo Messa, Colin Norman, Massimo Ricotti, Yoichi Tamura, Rogier A. Windhorst, Xinfeng Xu, Adi Zitrin · 发表于：The Astrophysical Journal · 年份：2025 · DOI：10.3847/1538-4357/adf638 · 被引用次数：6 · 研究领域：Galaxies: Formation, Evolution, Phenomena、Astrophysical Phenomena and Observations、Astrophysics and Star Formation Studies

Abstract We present recent JWST NIRCam imaging observations of SPT0615-JD (also known as the Cosmic Gems Arc), lensed by the galaxy cluster SPT-CL J0615−5746. The 5 ″ long arc is the most highly magnified z > 10 galaxy known. It straddles the lensing critical curve and reveals five star clusters with radii of ∼1 pc or less. We measure the full arc to have F200W 24.5 AB mag, consisting of two mirror images, each 25.3 AB mag with a median magnification of μ ∼ 6 0 − 8 + 17 (delensed 29.7 AB mag, M UV = −17.8). The galaxy has an extremely strong Lyman break F115W−F200W >3.2 mag (2 σ lower limit), is undetected in all bluer filters (<2 σ ), and has a very blue continuum slope redward of the break ( β = −2.7 ± 0.1). This results in a photometric redshift z phot = 10.2 ± 0.2 (95% confidence) with no significant likelihood below z < 9.8. Based on spectral energy distribution fitting to the total photometry, we estimate an intrinsic stellar mass of M * ∼ 2.4–5.6 × 10 7 M ⊙ , young mass-weighted age of ∼21–79 Myr, low dust content ( A V < 0.15), and a low metallicity of ≲1% Z ⊙ . We identify a fainter third counterimage candidate within 2 . ″ 2 of the predicted position, lensed to AB mag 28.4 and magnified by μ ∼ 2, suggesting the fold arc may only show ∼60% of the galaxy. SPT0615-JD is a unique laboratory to study star clusters observed within a galaxy just 460 Myr after the Big Bang.