TY - JOUR
T1 - Closing in on the sources of cosmic reionization
T2 - First results from the GLASS-JWST program
AU - Mascia, S.
AU - Pentericci, L.
AU - Calabrò, A.
AU - Treu, T.
AU - Santini, P.
AU - Yang, L.
AU - Napolitano, L.
AU - Roberts-Borsani, G.
AU - Bergamini, P.
AU - Grillo, C.
AU - Rosati, P.
AU - Vulcani, B.
AU - Castellano, M.
AU - Boyett, K.
AU - Fontana, A.
AU - Glazebrook, K.
AU - Henry, A.
AU - Mason, C.
AU - Merlin, E.
AU - Morishita, T.
AU - Nanayakkara, T.
AU - Paris, D.
AU - Roy, N.
AU - Williams, H.
AU - Wang, X.
AU - Brammer, G.
AU - Bradač, M.
AU - Chen, W.
AU - Kelly, P. L.
AU - Koekemoer, A. M.
AU - Trenti, M.
AU - Windhorst, R. A.
N1 - Funding Information:
Support for program JWST-ERS-1324 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. 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 programs GLASS-JWST #1324, JWST DDT #2756 and GO UNCOVER #2561. S.M. thanks the Department of Physics and Astronomy at the University of California, Los Angeles, for a productive and satisfying visit in which the majority of the work presented in this paper was done. We acknowledge support from the INAF Large Grant 2022 "Extragalactic Surveys with JWST" (PI: Pentericci). 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. L.Y. acknowledges support by JSPS KAKENHI Grant Number JP 21F21325. R.A.W. acknowledges support from NASA JWST Interdisciplinary Scientist grants NAG5-12460, NNX14AN10G and 80NSSC18K0200 from GSFC. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. C.M. acknowledges support by the VILLUM FONDEN under grant 37459. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. K.G. and T.N. acknowledge support from Australian Research Council Laureate Fellowship FL180100060.
Funding Information:
Support for program JWST-ERS-1324 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. 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 programs GLASS-JWST #1324, JWST DDT #2756 and GO UNCOVER #2561. S.M. thanks the Department of Physics and Astronomy at the University of California, Los Angeles, for a productive and satisfying visit in which the majority of the work presented in this paper was done. We acknowledge support from the INAF Large Grant 2022 “Extragalactic Surveys with JWST” (PI: Pentericci). 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. L.Y. acknowledges support by JSPS KAKENHI Grant Number JP 21F21325. R.A.W. acknowledges support from NASA JWST Interdisciplinary Scientist grants NAG5-12460, NNX14AN10G and 80NSSC18K0200 from GSFC. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. C.M. acknowledges support by the VILLUM FONDEN under grant 37459. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. K.G. and T.N. acknowledge support from Australian Research Council Laureate Fellowship FL180100060.
Publisher Copyright:
© The Authors 2023.
PY - 2023/4/1
Y1 - 2023/4/1
N2 - The escape fraction of Lyman-continuum (LyC) photons ( fesc) is a key parameter for determining the sources of cosmic reionization at z ≥ 6. At these redshifts, owing to the opacity of the intergalactic medium, the LyC emission cannot be measured directly. However, LyC leakers during the epoch of reionization could be identified using indirect indicators that have been extensively tested at low and intermediate redshifts. These include a high [Oiii]/[Oii] flux ratio, high star-formation surface density, and compact sizes. In this work, we present observations of 29 4:5 ≤ z ≤ 8 gravitationally lensed galaxies in the Abell 2744 cluster field. From a combined analysis of JWST-NIRSpec and NIRCam data, we accurately derived their physical and spectroscopic properties: our galaxies have low masses (log(M∗) ∼ 8:5), blue UV spectral slopes (β ∼ -2:1), compact sizes (re ∼ 0:3-0:5 kpc), and high [Oiii]/[Oii] flux ratios. We confirm that these properties are similar to those characterizing low-redshift LyC leakers. Indirectly inferring the fraction of escaping ionizing photons, we find that more than 80% of our galaxies have predicted fesc values larger than 0.05, indicating that they would be considered leakers. The average predicted fesc value of our sample is 0.12, suggesting that similar galaxies at z ≥ 6 have provided a substantial contribution to cosmic reionization.
AB - The escape fraction of Lyman-continuum (LyC) photons ( fesc) is a key parameter for determining the sources of cosmic reionization at z ≥ 6. At these redshifts, owing to the opacity of the intergalactic medium, the LyC emission cannot be measured directly. However, LyC leakers during the epoch of reionization could be identified using indirect indicators that have been extensively tested at low and intermediate redshifts. These include a high [Oiii]/[Oii] flux ratio, high star-formation surface density, and compact sizes. In this work, we present observations of 29 4:5 ≤ z ≤ 8 gravitationally lensed galaxies in the Abell 2744 cluster field. From a combined analysis of JWST-NIRSpec and NIRCam data, we accurately derived their physical and spectroscopic properties: our galaxies have low masses (log(M∗) ∼ 8:5), blue UV spectral slopes (β ∼ -2:1), compact sizes (re ∼ 0:3-0:5 kpc), and high [Oiii]/[Oii] flux ratios. We confirm that these properties are similar to those characterizing low-redshift LyC leakers. Indirectly inferring the fraction of escaping ionizing photons, we find that more than 80% of our galaxies have predicted fesc values larger than 0.05, indicating that they would be considered leakers. The average predicted fesc value of our sample is 0.12, suggesting that similar galaxies at z ≥ 6 have provided a substantial contribution to cosmic reionization.
KW - Early Universe
KW - Galaxies: clusters: intracluster medium
KW - Galaxies: evolution
KW - Galaxies: formation
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U2 - 10.1051/0004-6361/202345866
DO - 10.1051/0004-6361/202345866
M3 - Article
AN - SCOPUS:85153501051
SN - 0004-6361
VL - 672
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A155
ER -