Abstract

In extragalactic astrophysics, the mechanisms governing morphological evolution and structural diversity among high-z galaxies represent a key area of active research. In this talk, I will present JADES -GS+53.18343-27.79097, a galaxy of complex morphology, which existed during one of the earliest stages of the universe at z=7.43 (i.e. within its first 700 million years).

With a stellar mass exceeding 10^8.6 solar masses, this star-forming galaxy exhibits a multi-component structure, comprising of a compact core with a half-light radius of 144 parsecs, a vigorous star-forming disc spanning 468 parsecs, and a distinct star-forming clump, each characterised by unique star-formation histories. The central stellar mass density of this high-z galaxy approaches that of the most massive elliptical galaxies observed today, despite its total stellar mass being around only a one-thousandth of theirs. The galaxy also appears to be a possible progenitor of the kind of redshift 2 ellipticals we have seen previously.

Furthermore, the radial profile of the specific star-formation rate of the galaxy shows a sharp increase towards the outskirts, suggesting the detection of inside-out growth in a high-z galaxy within the first billion years of the Universe’s existence.