James Webb Space Telescope Feed Post

Arxiv: A luminous and young galaxy at z=12.33 revealed by a JWST/MIRI detection of Hα and [OIII] Published: 3/15/2024 7:26:02 PM Updated: 11/6/2024 5:45:25 PM

Paper abstract: The James Webb Space Telescope (JWST) has discovered a surprising populationof bright galaxies in the very early universe (<500 Myrs after the Big Bang)that is hard to explain with conventional galaxy formation models and whosephysical properties remain to be fully understood. Insight into their internalphysics is best captured through nebular lines but, at these early epochs, thebrightest of these spectral features are redshifted into the mid-infrared andremain elusive. Using the JWST Mid-Infrared Instrument, MIRI, here we presentthe first detection of H{\alpha} and doubly-ionized oxygen ([OIII]5007AA) atz>10. These detections place the bright galaxy GHZ2/GLASS-z12 atz=12.33+/-0.04, making it the most distant astronomical object with directspectroscopic detection of these lines. These observations provide key insightsinto the conditions of this primeval, luminous galaxy, which shows hardionizing conditions rarely seen in the local Universe likely driven by compactand young (~30Myr) burst of star formation. Its oxygen-to-hydrogen abundance isclose to a tenth of the solar value, indicating a rapid metal enrichment. Thisstudy confirms the unique conditions of this remarkably bright and distantgalaxy and the huge potential of mid-IR observations to characterize theseobjects.