Deep X-ray observation of NGC 3221: everything everywhere all at once
Sanskriti Das, Smita Mathur, Bret D. Lehmer, Steven W. Allen, Yair Krongold, Anjali Gupta

TL;DR
This paper presents a detailed X-ray analysis of NGC 3221, revealing a low-luminosity AGN, diverse ULX variability, new soft sources, and multi-phase hot gas in the galaxy's ISM and extraplanar regions.
Contribution
It provides the first comprehensive spatial, temporal, and spectral X-ray study of NGC 3221, identifying new sources and characterizing the hot gas phases in unprecedented detail.
Findings
Confirmed a low-luminosity, likely Compton-thick AGN.
Discovered two new soft X-ray sources, including a superbubble.
Characterized multi-phase hot gas with distinct temperature components.
Abstract
We present a comprehensive analysis of 475 ks (438 ks unpublished & 37 ks archival) XMM-Newton/EPIC-pn observation of a nearby, highly inclined, star-forming, luminous infrared galaxy NGC 3221 through spatial, temporal, and spectral information. We confirm the presence of a low-luminosity (presumably Compton-thick) AGN. The 0.412 keV luminosity and the hardness ratio of the six ultra-luminous X-ray sources (ULX) previously identified in Chandra data exhibit diverse variability on day-scale. The collective emission from unresolved sources exhibits a different day-scale variability. We have also discovered two new predominantly soft ( keV) sources. One of these has an enigmatic spectral shape featuring a soft component, which we interpret as a superbubble in NGC 3221, and a variable hard component from a compact object, which is unresolved from the superbubble. We do not…
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Taxonomy
TopicsAstrophysical Phenomena and Observations · Galaxies: Formation, Evolution, Phenomena · Astronomy and Astrophysical Research
