Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945
Abstract
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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2024
- DOI:
- arXiv:
- arXiv:2312.08444
- Bibcode:
- 2024ApJ...968...54P
- Keywords:
-
- Galactic winds;
- Starburst galaxies;
- 572;
- 1570;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 11 pages, 7 figures