Another X-ray UFO without a momentum-boosted molecular outflow. ALMA CO(1-0) observations of the galaxy pair IRAS 05054+1718

Abstract

We present ALMA CO(1-0) observations of the nearby LIRG galaxy pair IRAS05054+1718 with a new analysis of X-ray data collected between 2012 and 2021 using NuSTAR, Swift, and XMM-Newton. The western component of the pair, NED01, hosts a Seyfert 1.9 nucleus launching a powerful X-ray UFO. Our X-ray spectral analysis suggests the UFO could be variable or multi-component in velocity and constrains its momentum flux to ${\dot{p}}_{out}^{X-ray}\sim (4\pm 2)\times 10^{34}$ gcms${}^{-2}$. ALMA CO(1-0) observations include also the eastern component of the pair, a LIRG with no clear evidence for an AGN. We study the CO(1-0) kinematics in the two galaxies using the 3D-BAROLO code. In both sources, we can model the bulk of the CO(1-0) emission with rotating disks and, after subtracting the best-fit models, we detect compact residual emission at S/N=15 within $\sim 3$kpc from the centre. A molecular outflow in NED01, if present, cannot be brighter than such residuals, implying an upper limit on its outflow rate of ${\dot{M}}_{out}^{mol}\lesssim 19\pm 14M_{\odot }y{r}^{-1}$ and on its momentum rate of ${\dot{p}}_{out}^{mol}\lesssim (2.7\pm 2.4)\times 10^{34}$gcms${}^{-1}$. Combined with the revised energetics of the X-ray wind, we derive an upper limit on the momentum rate ratio of ${\dot{p}}_{out}^{mol}/{\dot{p}}_{out}^{X-ray}<0.67$. We discuss these results in the context of the expectations of AGN feedback models, and we propose the X-ray disk wind in NED01 has not significantly impacted the molecular gas reservoir (yet), and we can constrain its effect to be much smaller than expectations of AGN ''energy-driven'' feedback models. We also consider and discuss the hypothesis of asymmetries of the molecular disk not properly captured by the 3D-BAROLO code. Our results highlight the challenges in testing the predictions of popular AGN disk-wind feedback theories, even with good quality multi-wavelength observations.

Accepted by A&A