Back to Volume
Paper: Holes in the Sky: HII Regions in Absorption at 74 MHz for Galactic Cosmic-Ray Tomography
Volume: 345, From Clark Lake to the Long Wavelength Array: Bill Erickson's Radio Science
Page: 207
Authors: Nord, M.E.; Brogan, C.L.; Lazio, T.J.W.; Kassim, N.E.
Abstract: In order to test Cosmic Ray (CR) electron production, diffusion, and aging models, constraints must be made on the three-dimensional distribution of CR electron emissivity and energy spectrum. Historical CR tracers generally provide a line-of-sight integrated measurement of the CR emissivity. One must then account for Galactic structure in interpreting the observations. At low frequencies, HII regions become opaque and can be observed in absorption against the background Galactic CR emissivity. This measurement may be used to calculate the CR foreground and background emissivities along the line of sight to HII region at known distances. Many such observations have the potential to map out the three-dimensional distribution of Galactic CR emissivity.
Back to Volume