The Galactic Spatial Distribution of OB Associations and Their Surrounding Supernova-Generated Superbubble

Abstract

Core collapse supernovae of massive (> 8 Mo) stars are formed primarily in OB associations and help blow giant superbubbles, where their collective shocks accelerate most of the Galactic cosmic rays. The spatial distribution of these stars is thus important to our understanding of the propagation of the observed cosmic rays. In order to better model the Galactic cosmic-ray distribution and propagation, we construct s three-dimensional spatial model of the massive star distribution based primarily on the emission of the H II envelopes surrounding the giant superbubbles which are maintaned by the ionizing radiation of the embedded O stars. The Galactic longitudinal distribution of the 205 micron N II rsdistion emitted by these H II envelopes is used to infer the spatial distribution of the superbubbles. We find that the Galactic superbubble distribution is dominated by the contribution of massive star clusters residing in the spiral arms.

Submitted to the Astrophysical Journal, 22 January 2013

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Cited by in corpus (10)

• The Origin of Galactic Cosmic Rays
• The energy and momentum input of supernova explosions in structured and ionised molecular clouds
• OB associations and their origins
• Spiral Arms as Cosmic Ray Source Distributions
• Galactic Cosmic Ray Origins and OB Associations: Evidence from SuperTIGER Observations of Elements ${}_{26}$Fe through ${}_{40}$Zr
• Magnetic Spiral Arms and Galactic Outflows
• Cosmic rays from supernova remnants and superbubbles
• Extra-planar X-ray emission from disc-wide outflows in spiral galaxies
• A path towards constraining the evolution of the interstellar medium and outflows in the Milky Way using APOGEE
• Evidence for Coupling of Evolved Star Atmospheres and Spiral Arms of the Milky Way