NOEMA$^{\rm 3D}$: A first kpc resolution study of a $z\sim1.5$ main sequence barred galaxy channeling gas into a growing bulge

TL;DR

This study uses deep CO(3-2) observations of a $z oughly 1.5$ barred galaxy to reveal significant radial gas flows driven by the bar, suggesting bars play a key role in galaxy evolution during peak star formation epoch.

Contribution

First high-resolution kinematic analysis of a $z oughly 1.5$ barred galaxy showing bar-driven gas inflows, linking observations with simulations to understand galaxy evolution.

Findings

Radial velocities of about 60 km/s indicating strong non-circular motions.

Bar-driven inflows are comparable to the galaxy's star formation rate.

Bars may significantly influence galaxy growth during cosmic noon.

Abstract

We present a very deep CO(3-2) observation of a massive, gas-rich, main sequence, barred spiral galaxy at $z\approx1.52$. Our data were taken with the IRAM-NOEMA interferometer for a 12-antenna equivalent on-source integration time of $\sim$ 50 hours. We fit the major axis kinematics using forward modelling of a rotating disk, and then subtract the two-dimensional beam convolved best-fit model revealing signatures of planar non-circular motions in the residuals. The inferred in-plane radial velocities are remarkably large, of the order of $\approx60$ km/s. Direct comparisons with a high-resolution, simulated, gas-rich, barred galaxy, obtained with the moving mesh code AREPO and the TNG sub-grid model, show that the observed non-circular gas flows can be explained as radial flows driven by the central bar, with an inferred net inflow rate of the order of the SFR. Given the recent evidence for a higher-than-expected fraction of barred disk galaxies at cosmic noon, our results suggest that rapid gas inflows due to bars could be important evolutionary drivers for the dominant population of star-forming galaxies at the peak epoch of star and galaxy formation.