CaltechAUTHORS
Published January 1, 2023 | Version public
Journal Article Metadata-only

Early Results from GLASS-JWST. X. Rest-frame UV-optical Properties of Galaxies at 7 < z < 9

Creators

  • 1. ROR icon University of Melbourne
  • 2. ROR icon Centre of Excellence for All-Sky Astrophysics
  • 3. ROR icon National Astronomical Research Institute of Thailand
  • 4. ROR icon Astronomical Observatory of Rome
  • 5. ROR icon Kavli Institute for the Physics and Mathematics of the Universe
  • 6. ROR icon University of California, Los Angeles
  • 7. ROR icon University of Copenhagen
  • 8. ROR icon Swinburne University of Technology
  • 9. ROR icon University of California, Davis
  • 10. ROR icon Tufts University
  • 11. ROR icon Infrared Processing and Analysis Center
  • 12. ROR icon Agenzia Spaziale Italiana
  • 13. ROR icon University of Ljubljana
  • 14. ROR icon University of Minnesota

Abstract

We present the first James Webb Space Telescope/NIRCam-led determination of 7 < z < 9 galaxy properties based on broadband imaging from 0.8 to 5 μm as part of the GLASS-JWST Early Release Science program. This is the deepest data set acquired at these wavelengths to date, with an angular resolution ≲0farcs14. We robustly identify 13 galaxies with signal-to-noise ratio ≳ 8 in F444W from 8 arcmin² of data at m_AB ≤ 28 from a combination of dropout and photometric redshift selection. From simulated data modeling, we estimate the dropout sample purity to be ≳90%. We find that the number density of these F444W-selected sources is broadly consistent with expectations from the UV luminosity function determined from Hubble Space Telescope data. We characterize galaxy physical properties using a Bayesian spectral energy distribution fitting method, finding a median stellar mass of 10⁸·⁵ M_⊙ and age 140 Myr, indicating they started ionizing their surroundings at redshift z > 9.5. Their star formation main sequence is consistent with predictions from simulations. Lastly, we introduce an analytical framework to constrain main-sequence evolution at z > 7 based on galaxy ages and basic assumptions, through which we find results consistent with expectations from cosmological simulations. While this work only gives a glimpse of the properties of typical galaxies that are thought to drive the reionization of the universe, it clearly shows the potential of JWST to unveil unprecedented details of galaxy formation in the first billion years.

Additional Information

This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST-ERS-1324. We acknowledge financial support from NASA through grants JWST-ERS-1324. This research is supported in part by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. K.G. and T.N. acknowledge support from the Australian Research Council Laureate Fellowship FL180100060. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238.

Additional details

Identifiers

Eprint ID
119041
Resolver ID
CaltechAUTHORS:20230203-893794600.49

Funding

NASA
NAS 5-03127
NASA
JWST-ERS-1324
Australian Research Council
CE170100013
Australian Research Council
FL180100060
Slovenian Research Agency
N1-0238

Dates

Created
2023-03-02
Created from EPrint's datestamp field
Updated
2023-03-02
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)