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arXiv · 2410.10954

Spectroscopic confirmation of a dust-obscured, metal-rich dwarf galaxy at z~5

L. Bisigello·G. Gandolfi·A. Feltre·P. Arrabal Haro·A. Calabrò·N. J. Cleri·L. Costantin·G. Girardi·M. Giulietti·A. Grazian·C. Gruppioni·N. P. Hathi·B. W. Holwerda·M. Llerena·R. A. Lucas·F. Pacucci·I. Prandoni·G. Rodighiero·L. -M. Seillé·S. M. Wilkins·M. Bagley·M. Dickinson.·S. L. Finkelstein·J. Kartaltepe·A. M. Koekemoer·C. Papovich·N. Pirzkal
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Abstract

We present the first spectroscopic confirmation of a dust-obscured dwarf galaxy, CEERS-14821. The analysis is performed combining JWST NIRCam broad-band photometry and NIRSpec/PRISM spectroscopic data. From the detection of multiple rest-frame optical lines, we derive that CEERS-14821 is located at $z=4.883\pm0.003$. Moreover, from a secure detection of the $H_{\alpha}$ and $H_{\beta}$ we derived that the galaxy has a dust extinction ranging from Av=2.2 to Av=3.3, depending on the assumed reddening law. This value is extremely large given that we estimated a low stellar mass around log(M/Mo)=8.0-8.2. Moreover, using different metallicity tracers, we verify that the galaxy is also metal-rich, with 12+log(O/H)>8.3. This is well above the expectation from both the mass-metallicity relation and the fundamental mass-metalliticy relation. CEERS-14821 is going through a burst of star formation, there are no indications of a strong contribution from an active galactic nuclei (f(AGN)<0.5 with respect to the total dust luminosity). Based on the rest-frame optical images, this source has a size compatible with galaxies of similar stellar mass and redshift. Finally, with the current data, it seems that there are galaxies closely interacting with CEERS-14821.

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L. Bisigello, G. Gandolfi, A. Feltre, P. Arrabal Haro, A. Calabrò, N. J. Cleri, L. Costantin, G. Girardi, M. Giulietti, A. Grazian, C. Gruppioni, N. P. Hathi, B. W. Holwerda, M. Llerena, R. A. Lucas, F. Pacucci, I. Prandoni, G. Rodighiero, L. -M. Seillé, S. M. Wilkins, M. Bagley, M. Dickinson., S. L. Finkelstein, J. Kartaltepe, A. M. Koekemoer, C. Papovich, N. Pirzkal. 2024-10-14. Spectroscopic confirmation of a dust-obscured, metal-rich dwarf galaxy at z~5. https://doi.org/10.1051/0004-6361%2F202452604

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