Rogier A. Windhorst

JWST evidence for a sharp ``Cosmic Daybreak" at z=15

Abstract Luminous young galaxies have been uncovered with relative ease by JWST, extending to z=14.5, so it is puzzling that deeper spectroscopy of fainter candidates now finds only interlopers. This redshift `ìmpasse" is underscored by the measured stellar ages of these high-z g...

A Massive Barred Spiral Galaxy at z = 5.102 Discovered by JWST

Abstract We report M1149-BSG-z5, a barred spiral galaxy at z = 5.102, identified in the parallel field of MACS J1149+2223 with JWST and the Hubble Space Telescope. M1149-BSG-z5 is the highest-redshift barred galaxy candidate to date. Both isophote ellipse fitting and structural m...