Abstract

In extragalactic astrophysics, the mechanisms governing morphological evolution and structural diversity among galaxies represent fundamental enigmas. In this talk, I will present about JADES -GS+53.18343-27.79097, a galaxy of mature morphology, which emerged during one of the earliest stages of the universe, within its first 700 million years. With a stellar mass exceeding 10^8.6 solar masses, this star-forming galaxy exhibits a tripartite structure, comprising 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. Remarkably, the central stellar mass density of this high-z galaxy approaches that of the most massive elliptical galaxies observed today, despite its global mass being a mere one-thousandth of their scale. Furthermore, an intriguing revelation emerges from the radial profile of the specific star-formation rate—a pronounced increase towards the outskirts. This compelling evidence suggests the detection of inside-out growth within a high-z galaxy during the Epoch of Reionization, comprising of a proto-bulge and a star-forming disc.