Modeling the Outflow in the Narrow-Line Region of Markarian 573:Biconical Illumination of a Gaseous Disk

TL;DR

This study models the outflow of ionized gas in the narrow-line region of Seyfert galaxy Mrk 573, revealing the geometry of the ionizing bicone and its interaction with the inner disk, with implications for understanding AGN outflows.

Contribution

It provides a detailed geometric model of the outflow and inner disk interaction in Mrk 573, highlighting the larger true opening angle of the ionizing bicone.

Findings

The true half-opening angle of the ionizing bicone is 53 degrees.

The bicone intersects and illuminates the inner disk and spiral arms.

High velocities suggest rotation or in situ acceleration of gas.

Abstract

We present a study of the outflowing ionized gas in the resolved narrow-line region (NLR) of the Seyfert 2 galaxy Mrk 573, and its interaction with an in- ner dust/gas disk, based on Hubble Space Telescope (HST) WFPC2 and STIS observations. From the spectroscopic and imaging information, we determined the fundamental geometry of the outflow and inner disk, via two modeling pro- grams used to recreate the morphology of these regions imaged with HST. We also determined that the bicone of ionizing radiation from the Active Galactic Nucleus (AGN) intersects with the inner disk, illuminating a section of the disk including inner segments of spiral arms, fully seen through structure mapping, which appear to be outflowing and expanding. In addition, we see high velocities at projected distances of \geq 2'' (- 700 pc) from the nucleus, which could be due to rotation or to in situ acceleration of gas off the spiral arms. We find that the true half opening angle of the ionizing bicone (53 degrees) is much larger than the apparent half-opening angle (34 degrees) due to the above geometry, which may apply to a number of other Seyferts as well.