JWST spectroscopic confirmation of the Cosmic Gems arc at z=9.625: Insights into the small-scale structure of a post-burst system

MPG.PuRe (Max Planck Society) 2026

Authors: Messa, M., Vanzella, E., Loiacono, F., Adamo, A., Masamune Oguri, M., Sharon, K.
+53 more Bradley, L. D., Christensen, L., Claeyssens, A., Richard, J., Abdurro'uf, Bauer, F. E., Bergamini, P., Bolamperti, A., Maruša Bradač, M., Calura, F., Coe, D., Diego, J. M., Grillo, C., Hsiao, T. Y., Inoue, A. K., Fujimoto, S., Lombardi, M., Massimo Meneghetti, M., Resseguier, T., Ricotti, M., Rosati, P., Welch, B., Windhorst, R. A., Xu, X., Zackrisson, E., Zanella, A., Zitrin, A.
Cited by: 0

Abstract

We present JWST/NIRSpec integral field spectroscopy of the Cosmic Gems arc, strongly magnified by the galaxy cluster SPT-CL J0615-5746. Six-hour integration using NIRSpec prism spectroscopy (resolution R similar or equal to 30 - 300), covering the spectral range 0.8 - 5.3 mu m, reveals a pronounced Ly alpha-continuum break at lambda similar or equal to 1.3 mu m, as well as weak optical H beta and [O III] lambda 4959 emission lines at z = 9.625 +/- 0.002, located in the reddest part of the spectrum (lambda > 5.1 mu m). No additional ultraviolet or optical emission lines are reliably detected. A weak Balmer break is measured alongside a very blue ultraviolet slope (beta

Fields of Study & Subjects

Galaxies: Formation Evolution Phenomena Astrophysics and Star Formation Studies Stellar planetary and galactic studies

Publication details

Journal / source
MPG.PuRe (Max Planck Society)
Publication date
1 January 2026
Language
EN