Outflows from starburst galaxies with various driving mechanisms and their X-ray properties

Abstract

Outflows in starburst galaxies driven by thermal-mechanical energy, cosmic rays and their mix are investigated with 1D and 2D hydrodynamic simulations. We show that these outflows could reach a stationary state, after which their hydrodynamic profiles asymptotically approach previous results obtained semi-analytically for stationary outflow configurations. The X-rays from the simulated outflows are computed, and high-resolution synthetic spectra and broadband light curves are constructed. The simulated outflows driven by thermal mechanical pressure and CRs have distinguishable spectral signatures, in particular, in the sequence of the keV K𝛼 lines of various ions and in the L-shell Fe emission complex. We demonstrate that broadband colour analysis in X-rays is a possible alternative means to probe outflow driving mechanisms for distant galaxies, where observations may not be able to provide sufficient photons for high-resolution spectroscopic analyses.

Multi-wavelength emission from leptonic processes in ageing galaxy bubbles

“…Similar approaches have been adopted in other works -e.g. seeYu et al (2021), where the impact of CRs on galactic outflows is modeled numerically.3 Note that this approximation would not hold at higher redshifts, where inverse Compton cooling of electrons against cosmological microwave background radiation would substantially suppress the CR energy density within the bubble, if the CRs were predominantly comprised of electrons.…”