MIDIS: Unveiling the Role of Strong Hα Emitters During the Epoch of Reionization with JWST

Autor(en): P. Rinaldi, K. I. Caputi, E. Iani, L. Costantin, S. Gillman, P. G.Perez Gonzalez, G. Östlin, L. Colina, T. R. Greve, H. U. Nørgard-Nielsen, G. S. Wright, J. Álvarez-Márquez, A. Eckart, M. García-Marín, J. Hjorth, O. Ilbert, S. Kendrew, A. Labiano, O. Le Fèvre, J. Pye, T. Tikkanen, F. Walter, P. van der Werf, M. Ward, M. Annunziatella, R. Azzollini, A. Bik, L. Boogaard, S. E.I. Bosman, A. Crespo Gómez, I. Jermann, D. Langeroodi, J. Melinder, R. A. Meyer, T. Moutard, F. Peissker, E. van Dishoeck, M. Güdel, Th Henning, P. O. Lagage, T. Ray, B. Vandenbussche, C. Waelkens, Pratika Dayal
Abstrakt: By using an ultradeep JWST/MIRI image at 5.6 μm in the Hubble eXtreme Deep Field, we constrain the role of strong Hα emitters (HAEs) during “cosmic reionization” at z ≃ 7-8. Our sample of HAEs is comprised of young (<35 Myr) galaxies, except for one single galaxy (≈300 Myr), with low stellar masses (≲10⁹ M_☉). These HAEs show a wide range of rest-frame UV continuum slopes (β), with a median value of β = -2.15 ± 0.21, which broadly correlates with stellar mass. We estimate the ionizing photon production efficiency (ξ_ion,0) of these sources (assuming f_esc,LyC = 0%), which yields a median value log₁₀(x_ion,0 (Hz erg^-1)) = 25.50_-⁺_0.12^0.10. We show that ξ_ion,0 positively correlates with Hα equivalent width and specific star formation rate. Instead ξ_ion,0 weakly anticorrelates with stellar mass and β. Based on the β values, we predict f_esc,LyC = 4%_-⁺₂³, which results in log₁₀(x_ion (Hz erg^-1)) = 25.55_-⁺_0.13^0.11. Considering this and related findings from the literature, we find a mild evolution of ξ_ion with redshift. Additionally, our results suggest that these HAEs require only modest escape fractions (f_esc,rel) of 6%-15% to reionize their surrounding intergalactic medium. By only considering the contribution of these HAEs, we estimated their total ionizing emissivity (N_{(Equation presented)ion}) as N_{(Equation presented)ion} = 10^50.53±0.45 s^-1Mpc^-3. When comparing their N_{(Equation presented)ion} with non-HAE galaxies across the same redshift range, we find that that strong, young, and low-mass emitters may have played an important role during cosmic reionization.
Organisation(en): Institut für Astrophysik
Externe Organisation(en): University of Groningen, University of Copenhagen, Centro de Astrobiología (CSIC-INTA), Technical University of Denmark (DTU), Oskar Klein Centre, The Royal Observatory, Edinburgh, Universität zu Köln, European Space Astronomy Centre (ESA), Aix-Marseille Université, ESAC España, University of Leicester, Max-Planck-Institut für Astronomie, Leiden University, Durham University, INAF-Osservatorio Astronomico di Capodimonte, Dublin Institute for Advanced Studies, Eidgenössische Technische Hochschule Zürich, Université Paris Saclay, Katholieke Universiteit Leuven
Journal: Astrophysical Journal
Band: 969
Anzahl der Seiten: 15
ISSN: 0004-637X
DOI: https://doi.org/10.3847/1538-4357/ad4147
Publikationsdatum: 07-2024
Peer-reviewed: Ja
ÖFOS 2012: 103003 Astronomie, 103004 Astrophysik
ASJC Scopus Sachgebiete: Astronomy and Astrophysics, Space and Planetary Science
Link zum Portal: https://ucrisportal.univie.ac.at/de/publications/6b45e9a5-9af6-4ed4-831d-215cd6e9c3a0

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