A core in a star-forming disc as evidence of inside-out growth in the early Universe

William M. Baker; Sandro Tacchella; Benjamin D. Johnson; Erica Nelson; Katherine A. Suess; Francesco D'Eugenio; Mirko Curti; Anna de Graaff; Zhiyuan Ji; Roberto Maiolino; Brant Robertson; Jan Scholtz; Stacey Alberts; Santiago Arribas; Kristan Boyett; Andrew J. Bunker; Stefano Carniani; Stephane Charlot; Zuyi Chen; Jacopo Chevallard; Emma Curtis-Lake; A. Lola Danhaive; Christa DeCoursey; Eiichi Egami; Daniel J. Eisenstein; Ryan Endsley; Ryan Hausen; Jakob M. Helton; Nimisha Kumari; Tobias J. Looser; Michael V. Maseda; Dávid Puskás; Marcia Rieke; Lester Sandles; Fengwu Sun; Hannah Übler; Christina C. Williams; Christopher N. A. Willmer; Joris Witstok

arXiv · 2306.02472

A core in a star-forming disc as evidence of inside-out growth in the early Universe

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Abstract

The physical processes that establish the morphological evolution and the structural diversity of galaxies are key unknowns in extragalactic astrophysics. Here we report the finding of the morphologically-mature galaxy JADES-GS+53.18343-27.79097, which existed within the first 700 million years of the Universe's history. This star-forming galaxy with a stellar mass of 400 million solar masses consists of three components, a highly-compact core with a half-light radius of less than 100 pc, an actively star-forming disc with a radius of about 400 pc, and a star-forming clump, which all show distinctive star-formation histories. The central stellar mass density of this galaxy is within a factor of two of the most massive present-day ellipticals, while being globally 1000 times less massive. The radial profile of the specific star-formation rate is rising toward the outskirts. This evidence suggests the first detection of inside-out growth of a galaxy as a proto-bulge and a star-forming disc in the Epoch of Reionization.

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William M. Baker, Sandro Tacchella, Benjamin D. Johnson, Erica Nelson, Katherine A. Suess, Francesco D'Eugenio, Mirko Curti, Anna de Graaff, Zhiyuan Ji, Roberto Maiolino, Brant Robertson, Jan Scholtz, Stacey Alberts, Santiago Arribas, Kristan Boyett, Andrew J. Bunker, Stefano Carniani, Stephane Charlot, Zuyi Chen, Jacopo Chevallard, Emma Curtis-Lake, A. Lola Danhaive, Christa DeCoursey, Eiichi Egami, Daniel J. Eisenstein, Ryan Endsley, Ryan Hausen, Jakob M. Helton, Nimisha Kumari, Tobias J. Looser, Michael V. Maseda, Dávid Puskás, Marcia Rieke, Lester Sandles, Fengwu Sun, Hannah Übler, Christina C. Williams, Christopher N. A. Willmer, Joris Witstok. 2023-06-04. A core in a star-forming disc as evidence of inside-out growth in the early Universe. https://arxiv.org/abs/2306.02472

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