1. MIDIS : Strong (H beta plus [OIII]) and Ha Emitters at Redshift z similar or equal to 7-8 Unveiled with JWST NIRCam and MIRI Imaging in the Hubble eXtreme Deep Field
- Author
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Rinaldi, P., Caputi, K. I., Costantin, L., Gillman, S., Iani, E., Perez-Gonzalez, P. G., Östlin, Göran, Colina, L., Greve, T. R., Noorgard-Nielsen, H. U., Wright, G. S., Alonso-Herrero, A., Alvarez-Marquez, J., Eckart, A., Garcia-Marin, M., Hjorth, J., Ilbert, O., Kendrew, S., Labiano, A., Le Fevre, O., Pye, J., Tikkanen, T., Walter, F., van der Werf, P., Ward, M., Annunziatella, M., Azzollini, R., Bik, Arjan, Boogaard, L., Bosman, S. E. I., Gomez, A. Crespo, Jermann, I., Langeroodi, D., Melinder, Jens, Meyer, R. A., Moutard, T., Peissker, F., Topinka, M., van Dishoeck, E., Gudel, M., Henning, Th., Lagage, P. -O., Ray, T., Vandenbussche, B., Waelkens, C., Navarro-Carrera, R., Kokorev, V., Rinaldi, P., Caputi, K. I., Costantin, L., Gillman, S., Iani, E., Perez-Gonzalez, P. G., Östlin, Göran, Colina, L., Greve, T. R., Noorgard-Nielsen, H. U., Wright, G. S., Alonso-Herrero, A., Alvarez-Marquez, J., Eckart, A., Garcia-Marin, M., Hjorth, J., Ilbert, O., Kendrew, S., Labiano, A., Le Fevre, O., Pye, J., Tikkanen, T., Walter, F., van der Werf, P., Ward, M., Annunziatella, M., Azzollini, R., Bik, Arjan, Boogaard, L., Bosman, S. E. I., Gomez, A. Crespo, Jermann, I., Langeroodi, D., Melinder, Jens, Meyer, R. A., Moutard, T., Peissker, F., Topinka, M., van Dishoeck, E., Gudel, M., Henning, Th., Lagage, P. -O., Ray, T., Vandenbussche, B., Waelkens, C., Navarro-Carrera, R., and Kokorev, V.
- Abstract
We make use of JWST medium-band and broadband NIRCam imaging, along with ultradeep MIRI 5.6 mu m imaging, in the Hubble eXtreme Deep Field to identify prominent line emitters at z similar or equal to 7-8. Out of a total of 58 galaxies at z similar or equal to 7-8, we find 18 robust candidates ( similar or equal to 31%) for (H beta + [O III]) emitters, based on their enhanced fluxes in the F430M and F444W filters, with EW0(H beta +[O III]) similar or equal to 87-2100 angstrom. Among these emitters, 16 lie in the MIRI coverage area and 12 exhibit a clear flux excess at 5.6 mu m, indicating the simultaneous presence of a prominent Ha emission line with EW0(H alpha) similar or equal to 200-3000 angstrom. This is the first time that H alpha emission can be detected in individual galaxies at z > 7. The Ha line, when present, allows us to separate the contributions of H beta and [O III] to the (H beta +[O III]) complex and derive Ha-based star formation rates (SFRs). We find that in most cases [O III]/ H beta > 1. Instead, two galaxies have [O III]/H beta < 1, indicating that the NIRCam flux excess is mainly driven by H beta. Most prominent line emitters are very young starbursts or galaxies on their way to/from the starburst cloud. They make for a cosmic SFR density log(10)( rho(SFRH alpha) (M-circle dot yr(-1) Mpc))similar or equal to - 2.351 3 which is about a quarter of the total value (log(10)( SFR (M-circle dot yr(-1) Mpc))similar or equal to - 1.761 3 ) at z similar or equal to 7-8. Therefore, the strong Ha emitters likely had a significant role in reionization.
- Published
- 2023
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