Feedback by massive stars and the emergence of superbubbles II. X-ray properties

Abstract

In a previous paper we investigated the energy transfer of massive stars to the interstellar medium as a function of time and the geometrical configuration of three massive stars via 3D-mesh-refining hydrodynamics simulations, following the complete evolution of the massive stars and their supernovae except non-thermal processes . We analysed our ISM simulation results with the help of spectra for plasma temperatures between 0.1 and 10 keV and computed the spectral evolution and the spatio-temporal distribution of the hot gas. Results. Despite significant input of high temperature gas from supernovae and fast stellar winds, the resulting thermal X-ray spectra are generally very soft, with most of the emission well below 1 keV. We show that this is due to mixing triggered by resolved hydrodynamic instabilities. Supernovae enhance the X-ray luminosity of a superbubble by 1-2 orders of magnitude for a time span of about 0.1 Myr; longer if a supernova occurs in a larger superbubble and shorter in higher energy bands. Peak superbubble luminosities of the order of 10^{36} erg/s are reproduced well. The strong decay of the X-ray luminosity is due to bubble expansion, hydrodynamic instabilities related to the acceleration of the superbubble's shell thanks to the sudden energy input, and subsequent mixing. We also find global oscillations of our simulated superbubbles, which produce spatial variations of the X-ray spectrum, similar to what we see in the Orion-Eridanus cavity. We calculated the fraction of energy emitted in X-rays and find that with a value of a few times 10^{-4}, it is about a factor of ten below the measurements for nearby galaxies.

13 pages 12 figures, accepted by Astronomy & Astrophysics

References in corpus (12)

• Evidence for powerful AGN winds at high redshift: Dynamics of galactic outflows in radio galaxies during the "Quasar Era"
• The Current Status of Galaxy Formation
• Effects of Supernova Feedback on the Formation of Galaxy Disks
• HI holes and high-velocity clouds in the spiral galaxy NGC 6946
• The History and Future of the Local and Loop I Bubbles
• Diffuse, Non-Thermal X-ray Emission from the Galactic Star Cluster Westerlund 1
• Supergiant Shells and Molecular Cloud Formation in the LMC
• Three-Dimensional Simulations of Magnetized Superbubbles: New Insights into the Importance of MHD Effects on Observed Quantities
• Radio source stacking and the infrared / radio correlation at microJy flux densities
• A Cosmic Ray Resolution to the Superbubble Energy-Crisis
• XMM-Newton view of the N 206 superbubble in the Large Magellanic Cloud
• Eta Carinae across the 2003.5 Minimum: Analysis in the visible and near infrared spectral region

Cited by in corpus (8)

• The Physics of Star Cluster Formation and Evolution
• Wind bubbles within H II regions around slowly moving stars
• 26Al kinematics: superbubbles following the spiral arms? Constraints from the statistics of star clusters and HI supershells
• Dynamics and Energy Loss in Superbubbles
• The non-thermal superbubble in IC 10: the generation of cosmic ray electrons caught in the act
• Vertical position of the Sun with $\gamma$-rays
• Probing gaseous halos of galaxies with radio jets
• The ${}^{26}$Al Gamma-ray Line from Massive-Star Regions