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arxiv 2208.01612 v3 pith:CBI4ASXV submitted 2022-08-02 astro-ph.GA

A Comprehensive Study on Galaxies at z~9-16 Found in the Early JWST Data: UV Luminosity Functions and Cosmic Star-Formation History at the Pre-Reionization Epoch

classification astro-ph.GA
keywords galaxiesjwststar-formationcandidatescosmicdropoutearlyfunctions
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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We conduct a comprehensive study on dropout galaxy candidates at $z\sim9-16$ using the first 90 arcmin$^2$ JWST/NIRCam images taken by the early release observations (ERO) and early release science (ERS) programs. With the JWST simulation images, we find that a number of foreground interlopers are selected with a weak photo-$z$ determination ($\Delta\chi^2>4$). We thus carefully apply a secure photo-$z$ selection criterion ($\Delta\chi^2>9$) and conventional color criteria with confirmations of the ERO NIRSpec spectroscopic redshifts, and obtain a total of 23 dropout galaxies at $z\sim9-16$, including two candidates at $z_\mathrm{phot}=16.25_{-0.46}^{+0.24}$ and $16.41_{-0.55}^{+0.66}$. We perform thorough comparisons of dropout galaxies found in our work with recent JWST studies, and conclude that our galaxy sample is reliable enough for statistical analyses. We derive the UV luminosity functions at $z\sim9-16$, and confirm that our UV luminosity functions at $z\sim 9$ and $12$ agree with those determined by other HST and JWST studies. The cosmic star-formation rate density decreases from $z\sim9$ to $12$, and perhaps to $16$, but the densities at $z\sim12-16$ are higher than the constant star formation efficiency model. Interestingly, there are six bright galaxy candidates at $z\sim10-16$ with $M_\mathrm{UV}<-19.5$ mag and $M_*\sim10^{8-9} M_\odot$. Because a majority ($\sim80$\%) of these galaxies show no signatures of AGNs in their morphologies, the high cosmic star-formation rate densities and the existence of these UV-luminous galaxies are explained by no suppression of star-formation by the UV background radiation at the pre-reionization epoch and/or an efficient UV radiation production by a top-heavy IMF with Population III-like star formation.

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Forward citations

Cited by 6 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

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  2. Gamma-ray bursts reveal the history and faint contributors of cosmic reionization

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  6. Constraining Cosmological and Astrophysical Parameters with the Cosmic Star Formation History

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