Fwd:precise definition of 1 Crab

[Andrew Karam <karam.1@osu.edu>]

I don't know if this is still a topic of interest, but here's the precise
definition of 1 Crab (again, from my astronomer friend).

Andy

>   Finally got a definitive conversion factor for 1 Crab from one of my
>X-ray colleagues:
>
>1 crab = 7.28 x 10-8 erg/sq-cm/sec  from E=0.1-10 keV
>       = 1.33 x 10-8      "         from E=0.5-2.4 keV
>
>E refers to photon energy, E=h*nu
>
>As I suspected, Crab is total flux (energy/area/sec) integrated over a
>particular X-ray bandpass.  Now, the question is, which bandpass was 
>being used for the Gamma-Ray burst observations mentioned?


The opinions expressed above are well-reasoned and insightful.  Needless to
say, they are not those of my employer.(with apologies to Michael Feldman)


Andrew Karam, CHP				"The mind is not a vessel
karam.1@osu.edu				to be filled but a fire
						to be lighted." (Plutarch)
Ohio State University 
Radiation Safety Section
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