Searching for AGN Outflows: Spatially Resolved Chandra HETG Spectroscopy of the NLR Ionization Cone in NGC 1068

TL;DR

This study uses high-resolution Chandra HETG spectroscopy to spatially resolve and analyze the ionization cone in NGC 1068, revealing outflowing photoionized gas characteristics and ionization structure in the AGN's NLR.

Contribution

First spatially resolved high-resolution X-ray spectroscopy of an AGN ionization cone, providing detailed measurements of ionization, density, and temperature along the NLR.

Findings

NLR is outflowing photoionized gas

Evidence suggests no collisionally ionized gas from radio jet

Detected potential velocity gradients in the outflow

Abstract

We present initial results from a new 440-ks Chandra HETG GTO observation of the canonical Seyfert 2 galaxy NGC 1068. The proximity of NGC 1068, together with Chandra's superb spatial and spectral resolution, allow an unprecedented view of its nucleus and circumnuclear NLR. We perform the first spatially resolved high-resolution X-ray spectroscopy of the `ionization cone' in any AGN, and use the sensitive line diagnostics offered by the HETG to measure the ionization state, density, and temperature at discrete points along the ionized NLR. We argue that the NLR takes the form of outflowing photoionized gas, rather than gas that has been collisionally ionized by the small-scale radio jet in NGC 1068. We investigate evidence for any velocity gradients in the outflow, and describe our next steps in modeling the spatially resolved spectra as a function of distance from the nucleus.