Star Formation under a Cosmic Microscope: Highly magnified z = 11 galaxy behind the Bullet Cluster
Maruša Bradač, Jon Judež, Chris Willott, Gregor Rihtaršič, Nicholas S. Martis, Anishya Harshan, Giordano Felicioni, Yoshihisa Asada, Guillaume Desprez, Douglas Clowe, Anthony H. Gonzalez, Christine Jones, Brian C. Lemaux, Vladan Markov, Lamiya Mowla, Gaël Noirot, Annika H. G. Peter, Andrew Robertson, Ghassan T. E. Sarrouh, Marcin Sawicki, Tim Schrabback, Roberta Tripodi
公開日: 2025/9/24
Abstract
We present measurements of stellar population properties of a newly discovered spectroscopically confirmed $z=11.10^{+0.11}_{-0.26}$, gravitationally lensed galaxy, using JWST NIRSpec PRISM spectroscopy and NIRCam imaging. The arc is highly magnified by the Bullet Cluster (magnification factor ${\mu}=14.0^{+6.2}_{-0.3}$. It contains three star-forming components of which one is barely resolved and two are unresolved, giving intrinsic sizes of $\lesssim 10pc$. The clumps also contain ~50% of the total stellar mass. The galaxy formed the majority of its stars ~150Myr ago (by z~14). The spectrum shows a pronounced damping wing, typical for galaxies deep in the reionisation era and indicating a neutral IGM at this line of sight. The intrinsic luminosity of the galaxy is $0.086^{+0.008}_{-0.030} L^*$ (with $L^*$ being the characteristic luminosity for this redshift), making it the lowest luminosity spectroscopically confirmed galaxy at $z>10$ discovered to date.