Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945

Abstract

We analyze 330 ks of {\it Chandra} X-ray imaging and spectra of the nearby, edge-on starburst and Seyfert Type 2 galaxy NGC 4945 to measure the hot gas properties along the galactic outflows. We extract and model spectra from 15 regions extending from $-$0.55 kpc to $+$0.85 kpc above and below the galactic disk to determine the best-fit parameters and metal abundances. We find that the hot gas temperatures and number densities peak in the central regions and decrease along the outflows. These profiles are inconsistent with a spherical, adiabatically-expanding wind model, suggesting the need to include mass loading and/or a non-spherical outflow geometry. We estimate the mass outflow rate of the hot wind to be $1.6M_{\odot }{\mathrm{yr}}^{-1}$. Emission from charge exchange is detected in the northern outflow, and we estimate it contributes 12\% to the emitted, broad-band ($0.5-7$ keV) X-ray flux.

11 pages, 7 figures; submitted (13 December 2023), accepted ApJ (11 April 2023)

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Cited by in corpus (2)

• Observational Constraints on Cool Gas Clouds in M82's Starburst-Driven Outflow
• Revisiting Disk Winds in Active Galactic Nuclei as an Origin of Cosmic Gamma-ray and Neutrino Backgrounds