NOEMA spatially resolved view of the multi-phase outflow in IRAS17020+4544: a shocked wind in action?

TL;DR

This study uses NOEMA observations to spatially resolve a powerful, galaxy-scale multi-phase outflow in IRAS17020+4544, revealing a shocked wind interacting with the interstellar medium and providing insights into AGN feedback mechanisms.

Contribution

First spatially resolved the multi-phase outflow in IRAS17020+4544, demonstrating energy conservation and shock interaction with the galaxy's interstellar medium.

Findings

Outflow components located 2-3 kpc from the nucleus.

High velocity gas up to 1900 km/s not aligned with galaxy rotation.

Mass outflow rate of approximately 139 solar masses per year.

Abstract

The Narrow Line Seyfert 1 Galaxy IRAS17020+4544 is one of the few AGN where a galaxy-scale energy-conserving outflow was revealed. This paper reports on NOEMA observations addressed to constrain the spatial scale of the CO emission in outflow. The molecular outflowing gas is resolved in five components tracing approaching and receding gas, all located at a distance of 2-3~kpc on the West and East side of the active nucleus. This high velocity gas (up to v_out=~1900 km/s) is not coincident with the rotation pattern of the CO gas in the host galaxy disk. The estimated mass outflow rate shows that with a global mass output of $\dot{M}_{H_2}$=~139$\pm$20$~M_\odot$~yr$^{-1}$, this powerful galaxy-scale outflow is consistent with the wind conserving its energy, and with a momentum rate boost of a factor of ~30 compared to the momentum rate of the nuclear X-ray wind. Preliminary results from ancillary X-ray (Chandra) and radio images (e-MERLIN) are reported. While the nature of the radio source is not conclusive, the Chandra image may tentatively trace extended emission, as expected by an expanding bubble of hot X-ray gas. The outcome of the NOEMA analysis and of past and ongoing publications dedicated to the description of the outflow multi-band phenomenology in IRAS17020+4544 concur to provide compelling reasons to postulate that an outflow shocking with the galaxy interstellar medium is driving the multi-phase wind in this peculiar AGN.