MIDIS: The Relation between Strong (Hβ + [O iii]) Emission, Star Formation, and Burstiness around the Epoch of Reionization

Author(s): K. I. Caputi, P. Rinaldi, E. Iani, P. G. Pérez-González, G. Ostlin, L. Colina, T. R. Greve, H. U. Norgaard-Nielsen, G. S. Wright, J. Álvarez-Márquez, A. Eckart, J. Hjorth, A. Labiano, O. Le Fèvre, F. Walter, P. van der Werf, L. Boogaard, L. Costantin, A. Crespo Gómez, S. Gillman, I. Jermann, D. Langeroodi, J. Melinder, F. Peissker, M. Gudel, Th Henning, P. O. Lagage, T. P. Ray
Abstract: We investigate the properties of strong (Hβ + [O iii]) emitters before and after the end of the “Epoch of Reionization” from z = 8 to z = 5.5. We make use of ultradeep JWST/NIRCam imaging in the parallel field (P2) of the MIRI Deep Imaging Survey (MIDIS) in the Hubble eXtreme Deep Field (H-XDF), in order to select prominent (Hβ + [O iii]) emitters (with rest-frame equivalent width (EW₀) ≳ 100 Å) at z = 5.5-7, based on their flux density enhancement in the F356W band with respect to the spectral energy distribution continuum. We complement our selection with other (Hβ + [O iii]) emitters from the literature at similar and higher (z = 7−8) redshifts. We find (nonindependent) anticorrelations between EW₀(Hβ + [O iii]) and both galaxy stellar mass and age, in agreement with previous studies, and a positive correlation with specific star formation rate (sSFR). On the SFR-M ^⋆ plane, the (Hβ + [O iii]) emitters populate both the star formation main sequence and the starburst region, which become indistinguishable at low stellar masses ( log 10 ( M ⋆ ) < 7.5 ). We find tentative evidence for a nonmonotonic relation between EW₀(Hβ + [O iii]) and SFR, such that both parameters correlate with each other at SFR ≳ 1 M _⊙ yr⁻¹, while the correlation flattens out at lower SFRs. This suggests that low metallicities producing high EW₀(Hβ + [O iii]) could be important at low SFR values. Interestingly, the properties of the strong emitters and other galaxies (33% and 67% of our z = 5.5-7 sample, respectively) are similar, including, in many cases, high sSFR. Therefore, it is crucial to consider both emitters and nonemitters to obtain a complete picture of the cosmic star formation activity around the Epoch of Reionization.
Organisation(s): Department of Astrophysics
External organisation(s): University of Groningen, University of Copenhagen, European Space Astronomy Centre (ESA), Oskar Klein Centre, Technical University of Denmark (DTU), The Royal Observatory, Edinburgh, Universität zu Köln, Aix-Marseille Université, Max-Planck-Institut für Astronomie, Leiden University, Eidgenössische Technische Hochschule Zürich, Université Paris Saclay, Dublin Institute for Advanced Studies
Journal: Astrophysical Journal
Volume: 969
No. of pages: 10
ISSN: 0004-637X
DOI: https://doi.org/10.3847/1538-4357/ad4eb2
Publication date: 07-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/9a35e404-3002-4281-a0f1-e564ee772b7d

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