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

Leethochawalit, N. and Trenti, M. and Santini, P. and Yang, L. and Merlin, E. and Castellano, M. and Fontana, A. and Treu, T. and Mason, C. and Glazebrook, K. and Jones, T. and Vulcani, B. and Nanayakkara, T. and Marchesini, D. and Mascia, S. and Morishita, T. and Roberts-Borsani, G. and Bonchi, A. and Paris, D. and Boyett, K. and Strait, V. and Calabrò, A. and Pentericci, L. and Bradac, M. and Wang, X. and Scarlata, C. (2023) Early Results from GLASS-JWST. X. Rest-frame UV-optical Properties of Galaxies at 7 < z < 9. Astrophysical Journal Letters, 942 (2). Art. No. L26. ISSN 2041-8205. doi:10.3847/2041-8213/ac959b.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Leethochawalit, N.0000-0003-4570-3159
Trenti, M.0000-0001-9391-305X
Santini, P.0000-0002-9334-8705
Yang, L.0000-0002-8434-880X
Merlin, E.0000-0001-6870-8900
Castellano, M.0000-0001-9875-8263
Fontana, A.0000-0003-3820-2823
Treu, T.0000-0002-8460-0390
Mason, C.0000-0002-3407-1785
Glazebrook, K.0000-0002-3254-9044
Jones, T.0000-0001-5860-3419
Vulcani, B.0000-0003-0980-1499
Nanayakkara, T.0000-0003-2804-0648
Marchesini, D.0000-0001-9002-3502
Mascia, S.0000-0002-9572-7813
Morishita, T.0000-0002-8512-1404
Roberts-Borsani, G.0000-0002-4140-1367
Bonchi, A.0000-0002-2667-5482
Paris, D.0000-0002-7409-8114
Boyett, K.0000-0003-4109-304X
Strait, V.0000-0002-6338-7295
Calabrò, A.0000-0003-2536-1614
Pentericci, L.0000-0001-8940-6768
Bradac, M.0000-0001-5984-0395
Wang, X.0000-0002-9373-3865
Scarlata, C.0000-0002-9136-8876
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.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-03127
Australian Research CouncilCE170100013
Australian Research CouncilFL180100060
Slovenian Research AgencyN1-0238
Issue or Number:2
Record Number:CaltechAUTHORS:20230203-893794600.49
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:119041
Deposited By: Research Services Depository
Deposited On:02 Mar 2023 17:44
Last Modified:02 Mar 2023 17:44

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