FRAMEx IV: Mechanical Feedback from the Active Galactic Nucleus in NGC 3079

Abstract

Using the Very Long Baseline Array, we observed the active galactic nucleus (AGN) in NGC 3079 over a span of six months to test for variability in the two main parsec-scale radio components, $A$ and $B$, which lie on either side of the AGN. We found evidence for positional differences in the positions of $A$ and $B$ over the six months consistent with the apparent motion of these components extrapolated from older archival data, finding that their projected rate of separation, $(0.040\pm 0.003)$ c, has remained constant since $\sim 2004$ when a slowdown concurrent with a dramatic brightening of source $A$ occurred. This behavior is consistent with an interaction of source $A$ with the interstellar medium (ISM), as has previously been suggested in the literature. We calculated the amount of mechanical feedback on the ISM for both the scenario in which $A$ is an expulsion of material from the central engine and the scenario in which $A$ is a shock front produced by a relativistic jet, the latter of which is favored by several lines of evidence we discuss. We find that the cumulative mechanical feedback on the ISM is between $2\times 10^{44}$ erg to $1\times 10^{48}$ erg for the expulsion scenario or between $3\times 10^{50}$ erg to $1\times 10^{52}$ erg for the jet scenario. Integrated over the volume-complete FRAMEx sample, our results imply that jet-mode mechanical feedback plays a negligible role in the energetics of AGNs in the local universe.

13 pages, 3 figures; Accepted for publication in ApJ