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CEERS key paper. I. An early look into the first 500 Myr of galaxy formation with JWST

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posted on 2023-06-10, 06:50 authored by Steven L Finkelstein, Micaela B Bagley, Henry C Ferguson, Stephen WilkinsStephen Wilkins, Jeyhan S Kartaltepe, Casey Papovich, L Y Yung, Pablo A Haro, Peter Behroozi, Mark Dickinson, Dale D Kocevski, Anton M Koekemoer, Romeel L Larson, others
We present an investigation into the first 500 Myr of galaxy evolution from the Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one of 13 JWST ERS programs, targets galaxy formation from z ~ 0.5 to >10 using several imaging and spectroscopic modes. We make use of the first epoch of CEERS NIRCam imaging, spanning 35.5 arcmin2, to search for candidate galaxies at z > 9. Following a detailed data reduction process implementing several custom steps to produce high-quality reduced images, we perform multiband photometry across seven NIRCam broad- and medium-band (and six Hubble broadband) filters focusing on robust colors and accurate total fluxes. We measure photometric redshifts and devise a robust set of selection criteria to identify a sample of 26 galaxy candidates at z ~ 9-16. These objects are compact with a median half-light radius of ~0.5 kpc. We present an early estimate of the z ~ 11 rest-frame ultraviolet (UV) luminosity function, finding that the number density of galaxies at M UV ~ -20 appears to evolve very little from z ~ 9 to 11. We also find that the abundance (surface density [arcmin-2]) of our candidates exceeds nearly all theoretical predictions. We explore potential implications, including that at z > 10, star formation may be dominated by top-heavy initial mass functions, which would result in an increased ratio of UV light per unit halo mass, though a complete lack of dust attenuation and/or changing star formation physics may also play a role. While spectroscopic confirmation of these sources is urgently required, our results suggest that the deeper views to come with JWST should yield prolific samples of ultrahigh-redshift galaxies with which to further explore these conclusions.

History

Publication status

  • Published

File Version

  • Published version

Journal

Astrophysical Journal Letters

ISSN

2041-8205

Publisher

American Astronomical Society

Volume

946

Page range

L13 1-34

Department affiliated with

  • Physics and Astronomy Publications

Institution

University of Sussex

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2023-04-24

First Open Access (FOA) Date

2023-04-24

First Compliant Deposit (FCD) Date

2023-04-21

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