The Chandra/HETG view of NGC 1365 in a Compton-thick state

Abstract

We present the analysis of a Chandra High-Energy Transmission Grating (HETG) observation of the local Seyfert galaxy NGC 1365. The source, well known for its dramatic X-ray spectral variability, was caught in a reflection-dominated, Compton-thick state. The high spatial resolution afforded by Chandra allowed us to isolate the soft X-ray emission from the active nucleus, neglecting most of the contribution from the kpc-scale starburst ring. The HETG spectra thus revealed a wealth of He- and H-like lines from photoionized gas, whereas in larger aperture observations these are almost exclusively produced through collisional ionization in the circumnuclear environment. Once the residual thermal component is accounted for, the emission-line properties of the photoionized region close to the hard X-ray continuum source indicate that NGC 1365 has some similarities to the local population of obscured active galaxies. In spite of the limited overall data quality, several soft X-ray lines seem to have fairly broad profiles (~800-1300 km/s full-width at half maximum), and a range of outflow velocities (up to ~1600 km/s, but possibly reaching a few thousands km/s) appears to be involved. At higher energies, the K$\alpha$ fluorescence line from neutral iron is resolved with > 99 per cent confidence, and its width of ~3000 km/s points to an origin from the same broad-line region clouds responsible for eclipsing the X-ray source and likely shielding the narrow-line region.

11 pages, 6 figures, 3 tables. Accepted for publication in MNRAS

References in corpus (7)

• Revisiting the Unified Model of Active Galactic Nuclei
• Occultation measurement of the size of the X-ray emitting region in the Active Galactic Nucleus of NGC 1365
• On the origin of soft X-rays in obscured AGN: answers from high-resolution spectroscopy with XMM-Newton
• The Multi-Layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR
• NGC 1365: A low column density state unveiling a low ionization disk wind
• Long Term Wind-Driven X-Ray Spectral Variability of NGC 1365 with Swift
• XMM-Newton observation of Mrk 110

Cited by in corpus (11)

• ALMA observations of molecular tori around massive black holes
• MAGNUM survey: A MUSE-Chandra resolved view on ionized outflows and photoionization in the Seyfert galaxy NGC 1365
• Testing the accuracy of reflection-based supermassive black hole spin measurements in AGN
• Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy NGC 1365
• Investigating Changing-Look Active Galactic Nuclei with Long-term Optical and X-Ray Observations
• A high spectral resolution map of the nuclear emitting regions of NGC 7582
• Variable mass accretion and failed wind explain changing look phenomena in NGC 1365
• Direct observation of the Broad Line Region in X-rays during the low state of NGC4051
• An X-ray high-frequency quasi-periodic oscillation in NGC 1365
• X-ray narrow emission lines from the nuclear region of NGC 1365
• Hubble Space Telescope Observations of BALQSO Ton 34 Reveal a Connection between the Broad Line Region and the BAL Outflow