Star-Forming Galaxies at Cosmic Noon

TL;DR

This paper reviews recent observational advances in understanding star-forming galaxies around cosmic noon (z~2), highlighting key insights into galaxy evolution, structure formation, and future prospects with upcoming telescopes.

Contribution

It synthesizes current observational findings on galaxy properties, dynamics, and quenching mechanisms at z~2, emphasizing the role of secular processes and AGN activity in galaxy evolution.

Findings

Scaling relations are well established among massive galaxies at z~2.

Gravitational instabilities and secular processes influence early galaxy structure.

Kinematic observations probe baryon and dark matter distribution at z~2.

Abstract

Ever deeper and wider lookback surveys have led to a fairly robust outline of the cosmic star formation history, which culminated around z~2 -- a period often nicknamed "cosmic noon." Our knowledge about star-forming galaxies at these epochs has dramatically advanced from increasingly complete population censuses and detailed views of individual galaxies. We highlight some of the key observational insights that influenced our current understanding of galaxy evolution in the equilibrium growth picture: $\bullet$ scaling relations between galaxy properties are fairly well established among massive galaxies at least out to z~2, pointing to regulating mechanisms already acting on galaxy growth; $\bullet$ resolved views reveal that gravitational instabilities and efficient secular processes within the gas- and baryon-rich galaxies at z~2 play an important role in the early build-up of galactic structure; $\bullet$ ever more sensitive observations of kinematics at z~2 are probing the baryon and dark matter budget on galactic scales and the links between star-forming galaxies and their likely descendants; $\bullet$ towards higher masses, massive bulges, dense cores, and powerful AGN and AGN-driven outflows are more prevalent and likely play a role in quenching star formation. We outline emerging questions and exciting prospects for the next decade with upcoming instrumentation, including the James Webb Space Telescope and the next generation of Extremely Large Telescopes.