A magnified compact galaxy at redshift 9.51 with strong nebular emission lines
Hayley Williams, Patrick L. Kelly, Wenlei Chen, Gabriel Brammer, Adi Zitrin, Tommaso Treu, Claudia Scarlata, Anton M. Koekemoer, Masamune Oguri, Yu-Heng Lin, J. M. Diego, M. Nonino, J. Hjorth, Danial Langeroodi, Tom Broadhurst, Noah S. J. Rogers, I. Pérez‐Fournon, R. J. Foley, Saurabh W. Jha, A. V. Filippenko, Lou Strolger, Justin Pierel, F. Poidevin, Lilan Yang
Abstract
Ultraviolet light from early galaxies is thought to have ionized gas in the intergalactic medium. However, there are few observational constraints on this epoch because of the faintness of those galaxies and the redshift of their optical light into the infrared. We report the observation, in JWST imaging, of a distant galaxy that is magnified by gravitational lensing. JWST spectroscopy of the galaxy, at rest-frame optical wavelengths, detects strong nebular emission lines that are attributable to oxygen and hydrogen. The measured redshift is z = 9.51 ± 0.01, corresponding to 510 million years after the Big Bang. The galaxy has a radius of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mrow> <mml:mn>16.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>7.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.6</mml:mn> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> parsecs, which is substantially more compact than galaxies with equivalent luminosity at z ~ 6 to 8, leading to a high star formation rate surface density.