Signatures of Cool Gas Fueling a Star-Forming Galaxy at Redshift 2.3

TL;DR

This study provides direct observational evidence of intergalactic gas accretion fueling a star-forming galaxy at redshift 2.3, revealing kinematic signatures consistent with gas inflow contributing significantly to galaxy growth.

Contribution

It presents the first direct detection of gas accretion signatures in a typical distant star-forming galaxy, linking gas inflow to galaxy evolution.

Findings

Gas accretion rate is comparable to star-formation rate.

Distinct kinematic signatures indicate gas inflow.

Accretion significantly contributes to galaxy growth.

Abstract

Galaxies are thought to be fed by the continuous accretion of intergalactic gas, but direct observational evidence has been elusive. The accreted gas is expected to orbit about the galaxy's halo, delivering not just fuel for star-formation but also angular momentum to the galaxy, leading to distinct kinematic signatures. Here we report observations showing these distinct signatures near a typical distant star-forming galaxy where the gas is detected using a background quasar passing 26 kpc from the host. Our observations indicate that gas accretion plays a major role in galaxy growth since the estimated accretion rate is comparable to the star-formation rate.