On the Passage of Radiation Through Inhomogeneous, Moving Media. V. Line Absorption and Frequency Variations of Optical Depth
Abstract
In a rapidly moving, rapidly shearing medium in which individual partially ionized atoms absorb radiation at a fixed frequency, VL, in their rest frames, we demonstrate that the optical distance an observer can "see" into the medium depends sensitively on both the angle of observation relative to the flow direction and the observing frequency. For instance, observations at perpendicular incidence using frequencies much lower than VL, and observations in the direction of motion at frequencies much higher than VL, both show strong absorption relative to the absorption taking place at high frequencies (v > ) (perpendicular incidence) and low frequencies (1' > vL) (parallel incidence), respectively. Subject headings: hydromagnetics - pulsars - radiative transfer
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1974
- DOI:
- 10.1086/153019
- Bibcode:
- 1974ApJ...191..753L