NOEMA 3D : A first kiloparsec resolution study of a z ∼ 1.5 main sequence barred galaxy channeling gas into a growing bulge

We present a very deep CO(3–2) observation of a massive, gas-rich, main sequence, barred spiral galaxy at z ≈ 1.52. Our data were taken with the IRAM-NOEMA interferometer for a 12-antenna equivalent on-source integration time of ∼50 hours. We fit the major axis kinematics with the forward modeling of a rotating disk and subtracted the two-dimensional beam convolved best-fit model, which revealed signatures of planar noncircular motions in the residuals. The inferred in-plane radial velocities are remarkably high, of the order of ≈60 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 noncircular gas flows can be explained as radial flows driven by the central bar, with an inferred net inflow rate of the order of the star formation rate (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.