The WMAP haze from the Galactic Center region due to massive star explosions and a reduced cosmic ray scale height

TL;DR

This paper explains the WMAP haze as a result of cosmic rays from supernova shocks in massive star winds, with a modified diffusion model predicting specific radio spectra.

Contribution

It introduces a model linking supernova shock acceleration and reduced cosmic ray diffusion to explain the WMAP haze with specific spectral predictions.

Findings

Cosmic ray electrons produce the WMAP haze with an E^-2 spectrum at injection.

Transport effects steepen the spectrum to E^-7/3, matching observations.

Predicted radio spectra vary with frequency, from u^-2/3 to u^-3/2.

Abstract

One important prediction of acceleration of particles in the supernova caused shock in the magnetic wind of exploding Wolf Rayet and Red Super Giant stars is the production of an energetic particle component with an E^-2 spectrum, at a level of a few percent in flux at injection. After allowing for transport effects, so steepening the spectrum to E^-7/3, this component of electrons produces electromagnetic radiation and readily explains the WMAP haze from the Galactic Center region in spectrum, intensity and radial profile. This requires the diffusion time scale for cosmic rays in the Galactic Center region to be much shorter than in the Solar neighborhood: the energy for cosmic ray electrons at the transition between diffusion dominance and loss dominance is shifted to considerably higher particle energy. We predict that more precise observations will find a radio spectrum of \nu^-2/3, at higher frequencies \nu^-1, and at yet higher frequencies finally \nu^-3/2.