Star formation under a cosmic microscope: highly magnified z = 11 galaxy behind the bullet clusterBradač, Maruša (Avtor) Judež, Jon (Avtor) Rihtaršič, Gregor (Avtor) Martis, Nicholas S. (Avtor) Harshan, Anishya (Avtor) Felicioni, Giordano (Avtor) Markov, Vladan (Avtor) Tripodi, Roberta (Avtor) galaxiesgravitational lensingspectroscopyphotometryWe 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 $\lesssim 10$ pc. The clumps also contain $\sim 50\%$ of the total stellar mass. The galaxy formed the majority of its stars $\sim 150$ Myr ago (by $z \sim 14$). The spectrum shows a pronounced damping wing, typical for galaxies deep in the reionization era and indicating a neutral intergalactic medium 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.20252026-01-23 11:15:49Članek v reviji178340sl