%0 Generic %1 mascia2023closing %A Mascia, S. %A Pentericci, L. %A Calabro', A. %A Treu, T. %A Santini, P. %A Yang, L. %A Napolitano, L. %A Roberts-Borsani, G. %A Bergamini, P. %A Grillo, C. %A Rosati, P. %A Vulcani, B. %A Castellano, M. %A Boyett, K. %A Fontana, A. %A Glazebrook, K. %A Henry, A. %A Mason, C. %A Merlin, E. %A Morishita, T. %A Nanayakkara, T. %A Paris, D. %A Roy, N. %A Williams, H. %A Wang, X. %A Brammer, G. %A Bradac, M. %A Chen, W. %A Kelly, P. L. %A Koekemoer, A. M. %A Trenti, M. %A Windhorst, R. A. %D 2023 %K library %T Closing in on the sources of cosmic reionization: first results from the GLASS-JWST program %U http://arxiv.org/abs/2301.02816 %X The escape fraction of Lyman continuum (LyC) photons ($f_esc$) is a key parameter for determining the sources of cosmic reionization at $z6$. At these redshifts, owing to the opacity of the intergalactic medium, 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 redshift. These include a high OIII/OII flux ratio, a high star formation surface density and a compact size. 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 derive their physical and spectroscopic properties: our galaxies have low masses $(łog(M_\star)8.5)$, blue UV spectral slopes ($-2.1$), compact sizes ($r_e 0.3-0.5$ kpc), and high OIII/OII flux ratios. Such properties are similar to those of low-redshift LyC leakers. Indirectly inferring the fraction of escaping ionizing photons, we find that more than 80\% of our galaxies have predicted $f_esc$ larger than 0.05, i.e. they would be considered leakers. The average predicted $f_esc$ of our sample is 0.12, suggesting that similar galaxies at $z6$ provided a substantial contribution to cosmic reionization.

@misc{mascia2023closing, abstract = {The escape fraction of Lyman continuum (LyC) photons ($f_{esc}$) is a key parameter for determining the sources of cosmic reionization at $z\geq 6$. At these redshifts, owing to the opacity of the intergalactic medium, 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 redshift. These include a high [OIII]/[OII] flux ratio, a high star formation surface density and a compact size. In this work we present observations of 29 $4.5 \leq z \leq 8$ gravitationally lensed galaxies in the Abell 2744 cluster field. From a combined analysis of JWST-NIRSpec and NIRCam data we accurately derive their physical and spectroscopic properties: our galaxies have low masses $(\log(M_\star)\sim 8.5)$, blue UV spectral slopes ($\beta \sim -2.1$), compact sizes ($r_e \sim 0.3-0.5$ kpc), and high [OIII]/[OII] flux ratios. Such properties are similar to those of low-redshift LyC leakers. Indirectly inferring the fraction of escaping ionizing photons, we find that more than 80\% of our galaxies have predicted $f_{esc}$ larger than 0.05, i.e. they would be considered leakers. The average predicted $f_{esc}$ of our sample is 0.12, suggesting that similar galaxies at $z\geq 6$ provided a substantial contribution to cosmic reionization.}, added-at = {2023-01-10T05:56:13.000+0100}, author = {Mascia, S. and Pentericci, L. and Calabro', A. and Treu, T. and Santini, P. and Yang, L. and Napolitano, L. and Roberts-Borsani, G. and Bergamini, P. and Grillo, C. and Rosati, P. and Vulcani, B. and Castellano, M. and Boyett, K. and Fontana, A. and Glazebrook, K. and Henry, A. and Mason, C. and Merlin, E. and Morishita, T. and Nanayakkara, T. and Paris, D. and Roy, N. and Williams, H. and Wang, X. and Brammer, G. and Bradac, M. and Chen, W. and Kelly, P. L. and Koekemoer, A. M. and Trenti, M. and Windhorst, R. A.}, biburl = {https://www.bibsonomy.org/bibtex/297d62238ec9c7fcc76c703e887f9a68f/gpkulkarni}, description = {Closing in on the sources of cosmic reionization: first results from the GLASS-JWST program}, interhash = {5d0dafb45a5f2bf037084b4f93035652}, intrahash = {97d62238ec9c7fcc76c703e887f9a68f}, keywords = {library}, note = {cite arxiv:2301.02816Comment: submitted to A&A, 11 pages, 8 figures}, timestamp = {2023-01-10T05:56:13.000+0100}, title = {Closing in on the sources of cosmic reionization: first results from the GLASS-JWST program}, url = {http://arxiv.org/abs/2301.02816}, year = 2023 }