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Observations Of Cygnus X-1 Comptel During 1991, Mark L. Mcconnell, D J. Forrest, James M. Ryan, W Collmar, V. Schonfelder, H Steinle, A W. Strong, R Van Dijk, W Hermsen, K Bennett
Observations Of Cygnus X-1 Comptel During 1991, Mark L. Mcconnell, D J. Forrest, James M. Ryan, W Collmar, V. Schonfelder, H Steinle, A W. Strong, R Van Dijk, W Hermsen, K Bennett
Physics & Astronomy
The Compton Telescope (COMPTEL) experiment on the Compton Gamma-Ray Observatory (CGRO) has observed the Cygnus region on two occasions during the first (sky survey) phase of its mission. These data represent the most sensitive observations to date of Cygnus X-1 in the 0.75-30 MeV range. The observations in 1991 June and August both showed evidence for emission in the 0.75-2 MeV energy range. The flux level was larger by about a factor of 2 during the August observation. The spectral data were analyzed in the context of a Wien spectral model (the high-energy limit of the Sunyaev-Titarchuk Comptonization spectrum). Fits …
On The Theory Of Astronomical Masers In Three Dimensions, Moshe Elitzur
On The Theory Of Astronomical Masers In Three Dimensions, Moshe Elitzur
Physics and Astronomy Faculty Publications
In the standard theory of three-dimensional astronomical masers, the radiation field is described as if the source were comprised of a collection of linear masers. To leading order, the standard theory is shown to provide the correct description of three-dimensional masers and its results remain intact, but only within a frequency core whose half-width is χsΔνD, where ΔνD is the Doppler width and χs is a dimensionless parameter. For any given geometry, χs is ~1θsat, where θsat is the beaming angle of a maser with that geometry that has …