The Astrophysical Journal (Jan 2024)

Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945

  • Natalia Porraz Barrera,
  • Sebastian Lopez,
  • Laura A. Lopez,
  • Adi Foord,
  • Dustin D. Nguyen,
  • Todd A. Thompson,
  • Smita Mathur,
  • Alberto D. Bolatto

DOI
https://doi.org/10.3847/1538-4357/ad4606
Journal volume & issue
Vol. 968, no. 2
p. 54

Abstract

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We analyze 330 ks of 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 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 nonspherical outflow geometry. We estimate the mass outflow rate of the hot wind to be 1.6 M _⊙ yr ^−1 . Emission from charge exchange is detected in the northern outflow, and we estimate it contributes 12% to the emitted, broadband (0.5–7 keV) X-ray flux.

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