James Webb Space Telescope Feed Post

NGDEEP Epoch 1: The Faint-End of the Luminosity Function at z~9-12 from Ultra-Deep JWST Imaging

Color composite (b=F115W+F150W, g=F200W+F277W, r=F277W+F356W) image of the NGDEEP field from our NIRCam mosaics. These fully reduced mosaics will be made publicly available following the NGDEEP release schedule. The NIRCam imaging reaches 29.9–30.4 AB mag, making it the deepest public JWST imaging dataset at the time of writing. We present a robust sample of very high-redshift galaxy candidates from the first epoch of {\it JWST}/NIRCam imaging from the Next Generation Extragalactic Exploratory Deep (NGDEEP) Survey. The NGDEEP NIRCam imaging in the Hubble Ultra Deep Field Parallel Field 2 (HUDF-Par2) reaches m=30.4 (5s, point-source) in F277W, making it the deepest public {\it JWST} GO imaging dataset to date. We describe our detailed data reduction process of the six-filter broad-band {\it JWST}/NIRCam imaging, incorporating custom corrections for systematic effects to produce high-quality calibrated images. Using robust photometric redshift selection criteria, we identify a sample of 38 z?9 galaxy candidates. These objects span a redshift range of z=8.5-15.8, and apparent magnitudes of mF277W=27-30.5 AB mag, reaching ~1.5 mag deeper than previous public {\it JWST} imaging surveys. We calculate the rest-frame ultraviolet (UV) luminosity function at z~ 9 and 11, and present a new measurement of the luminosity function faint-end slope at z~11. There is no significant evolution in the faint-end slope and number density from z=9 to 11. Comparing our results with theoretical predictions, we find that some models produce better agreement at the faint end than the bright end. These results will help to constrain how stellar feedback impacts star formation at these early epochs. Read more at the article.