Feeding Versus Feedback in AGNs from Near-Infrared IFU Observations: The Case of Mrk79

TL;DR

This study maps the gas dynamics and emission in the inner 680pc of Seyfert galaxy Mrk79, revealing spiral arms feeding the nucleus and ionized gas outflows driven by a nuclear jet, with implications for AGN fueling and feedback.

Contribution

It provides detailed 2D near-IR observations of gas kinematics and flux distributions in Mrk79, highlighting the feeding channels and outflow mechanisms in this Seyfert galaxy.

Findings

Spiral arms extend ~700pc, indicating gas inflow towards the nucleus.

Mass inflow rate (~4E-3 M_sun/year) is smaller than the accretion rate needed for the AGN.

Ionized gas outflow rate (~3.5 M_sun/year) exceeds the accretion rate, driven by the nuclear jet.

Abstract

We have mapped the gaseous kinematics and the emission-line flux distributions and ratios from the inner ~680pc radius of the Seyfert 1 galaxy Mrk79, using two-dimensional (2D) near-IR J- and Kl-band spectra obtained with the Gemini instrument NIFS at a spatial resolution of ~100pc and velocity resolution of ~40km/s. The molecular hydrogen flux distribution presents two spiral arms extending by ~700pc, one to the north and another to the south of the nucleus, with an excitation indicating heating by X-rays from the central source. The low velocity dispersion (sigma~50km/s) and rotation pattern supports a location of the H2 gas in the disk of the galaxy. Blueshifts observed along the spiral arm in the far side of the galaxy and redshifts in the spiral arm in the near side, suggest that the spiral arms are feeding channels of H2 to the inner 200pc. From channel maps along the H2 l2.1218um emission-line profile we estimate a mass inflow rate of ~4E-3 M_Sun/year, which is one order of magnitude smaller than the mass accretion rate necessary to power the AGN of Mrk79. The emission from the ionized gas (traced by Pabeta and [FeII]l1.2570um emission lines) is correlated with the radio jet and with the narrow-band [OIII] flux distribution. Its kinematics shows both rotation and outflows to the north and south of the nucleus. The ionized gas mass outflow rate through a cross section with radius ~320pc located at a distance of ~455pc from the nucleus is 3.5 MSun/year, which is much larger than the AGN mass accretion rate, indicating that most of the outflowing gas originates in the interstellar medium surrounding the galaxy nucleus, which is pushed away by a nuclear jet.