X-Rays Associated with High Energy Particles

Abstract

A number of recent results in X-ray astronomy, particularly from the Einstein Observatory, are relevant to the acceleration or interaction of high energy particles. X-ray observations of M stars by the Einstein Observatory indicate that their frequent flares include X-ray emission. The correspondence of the flux and duration of M star X-ray flares to those of solar flares can be used to estimate the rate of >200 MeV proton injection into the galaxy. Given the uncertainties, there is no disagreement with the cosmic ray density. Thus, a two stage acceleration process may be viable at least for protons.

Supernova remnants (SNR’s) are characterized by hot, turbulent shock waves with temperatures in excess of 10⁶ K to age 10⁴ years as seen, for example, in the Vela SNR. Thus, SNR’s are good candidates as cosmic ray acceleration sites. X-ray jets due to particle beams are seen to emanate from SS433 and G109.1–1.0, two objects where SNR’s are associated with compact X-ray sources.

Among extragalactic X-ray sources, the radio galaxies, Cen A and M87, have X-ray jet features emanating from their centers. M87 has more extended X-ray lobes in addition. These M87 features are due to synchrotron radiation of very high energy electrons and inverse Compton scattering of moderately high energy electrons against the 2.7K background.