The location and impact of jet-driven outflows of cold gas: the case of 3C293

TL;DR

This study uses high-resolution VLA observations to locate and analyze a fast neutral hydrogen outflow driven by the radio jet in galaxy 3C293, revealing its position and impact on the galaxy's interstellar medium.

Contribution

First high-resolution detection of the jet-driven neutral hydrogen outflow in 3C293, clarifying its location and relation to ionized gas outflows.

Findings

HI outflow velocity ~1200 km/s

Outflow rate 8-50 solar masses per year

Kinetic energy injection just outside effective feedback range

Abstract

The nearby radio galaxy 3C293 is one of a small group of objects where extreme outflows of neutral hydrogen have been detected. However, due to the limited spatial resolution of previous observations, the exact location of the outflow was not able to be determined. In this letter, we present new higher resolution VLA observations of the central regions of this radio source and detect a fast outflow of HI with a FWZI velocity of \Delta v~1200 km/s associated with the inner radio jet, approximately 0.5 kpc west of the central core. We investigate possible mechanisms which could produce the observed HI outflow and conclude that it is driven by the radio-jet. However, this outflow of neutral hydrogen is located on the opposite side of the nucleus to the outflow of ionised gas previously detected in this object. We calculate a mass outflow rate in the range of 8-50 solar masses/yr corresponding to a kinetic energy power injected back into the ISM of 1.38x10^{42} - 1.00x10^{43} erg/s or 0.01 - 0.08 percent of the Eddington luminosity. This places it just outside the range required by some galaxy evolution simulations for negative feedback from the AGN to be effective in halting star-formation within the galaxy.