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

TL;DR

This study used VLBA observations over six months to analyze the active galactic nucleus in NGC 3079, providing insights into the interaction of radio components with the interstellar medium and estimating the mechanical feedback from the AGN.

Contribution

It presents the first multi-epoch VLBA measurements of the AGN in NGC 3079, supporting the jet scenario for radio component A and quantifying the mechanical feedback on the ISM.

Findings

The projected separation rate of components A and B has remained constant since 2004.

Evidence favors the shock front scenario over the expulsion scenario for component A.

Mechanical feedback from the jet is negligible in the context of local universe AGNs.

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, $(0.040\pm0.003)$ c, has remained constant since $\sim2004$ 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.