The origin of cosmic rays. I - Observations of the spiral galaxy NGC 3310

Abstract

An observational technique is presented for addressing the problem of the origin of cosmic rays in galaxies by determining and comparing the distributions of cosmic rays, stars, and thermal gas. It is argued that optical continuum, emission line, and radio continuum imaging can be used to determine the distributions of the major stellar populations, the ionized gas, and the cosmic rays in galactic disks. An application of the technique is demonstrated by presenting and discussing observations of the spiral galaxy, NGC 3310. A preliminary analysis points to a possible spiral arm origin but argues against conventional models of cosmic-ray production such as supernova remnants. 38 references.