NOEMA$^\rm{3D}$: A deep view of cold gas flows in a barred spiral galaxy at $z\sim 1$

Abstract

We present a deep, high-resolution CO(4-3) IRAM-NOEMA observation of a main sequence, barred, spiral galaxy at $z\approx 1.12$, with an on-source integration time of $\approx 37$ hours and a beam FWHM of $\approx 0.{}^{\prime \prime }3$. We use the molecular gas data in conjunction with the available deep multi-band JWST and HST imaging, covering restframe UV to near-IR wavelengths, to quantitatively study the gas flows in the disk plane of this cosmic noon barred spiral. We find that this target is a massive ($\log (M_{\mathrm{baryons}}/M_{\odot })\approx 10.96$), baryon-dominated ($f_{\mathrm{dm}}(<R_e)=u_{\mathrm{circ},\mathrm{dm}}^2(R_e)/u_{\mathrm{circ}}^2(R_e)\sim 4\%$), gas-rich ($f_{\mathrm{gas}}=M_{\mathrm{gas}}/(M_{\star }+M_{\mathrm{gas}})\approx 40\%$) disk, hosting a long ($a_{\mathrm{bar}}\approx 4.2$ kpc), strong ($Q_{\mathrm{b}}\approx 0.37$), and fast ($\mathcal{R}=R_{\mathrm{CR}}/a_{\mathrm{bar}}\approx 1.05$) bar, which rotates at an angular speed of $\hat{I}{\text{c◯}}_{\mathrm{pattern}}\approx$ 50 km/s/kpc. This bar is driving molecular gas inflows with a net inflow rate of $\dot{M}\sim 30$ $M_{\odot }$/yr, based on three estimates, which is of the same order as the galaxy-integrated star formation rate ($\mathrm{SFR}\approx 36$ $M_{\odot }$/yr). We additionally identify evidence of a well-defined dust lane shock at the northwestern side of the bar, with gas motions parallel to this feature, in agreement with expectations for an established bar-driven flow. Our study highlights the possible role of bars as key drivers of galaxy evolution for a significant fraction of cosmic noon galaxies, offering a detailed picture of well-defined, bar-driven inflows in a high-$z$ barred spiral.

32 pages, 30 figures, submitted to A&A