Spiral morphology in an intensely star-forming disk galaxy more than 12 billion years ago

TL;DR

This study presents evidence of spiral galaxy structures, including spiral arms, in a galaxy more than 12 billion years ago, indicating early formation of such features in cosmic history.

Contribution

First detection of spiral morphology in a high-redshift galaxy, showing that complex galactic structures existed early in the universe.

Findings

Spiral arms observed at redshift 4.41, more than 12 billion years ago.

Presence of a central bulge and rotating gas disk in a distant galaxy.

Spiral features formed within 1.4 billion years after the Big Bang.

Abstract

Spiral galaxies have distinct internal structures including a stellar bulge, disk and spiral arms. It is unknown when in cosmic history these structures formed. We analyze observations of BRI 1335-0417, an intensely star-forming galaxy in the distant Universe, at redshift 4.41. The [C II] gas kinematics show a steep velocity rise near the galaxy center and have a two-armed spiral morphology that extends from about 2 to 5 kiloparsecs in radius. We interpret these features as due to a central compact structure, such as a bulge, a rotating gas disk and either spiral arms or tidal tails. These features had been formed within 1.4 billion years after the Big Bang, long before the peak of cosmic star formation.