functions in drat.i - B

    B_nu(hnu, kt)  


returns the specific intensity emitted by a black surface at  
photon energy HNU and temperature KT.  The units of HNU and KT  
must be the same.  The units of the result are determined by  
the variable B_nu_scale, which must be consistent with the units  
of HNU and KT.  B_nu_scale is the Stefan-Boltzmann constant  
(sigma in sigma*T^4) times 15/pi^5.  By default, B_nu_scale is  
set to 0.05040366 ((jrk/sh)/(cm^2 ster))/keV^4.  (1 jrk/sh =  
10^17 W)  
HNU and KT may be arrays, provided they are conformable.  
Interpreted function, defined at i0/drat.i   line 959  

    B_nu_bar(hnub, kt)  


returns the specific intensity emitted by a black surface at  
temperature KT in the energy bins whose boundary energies are  
HNUB.  HNUB must be a 1-D array of bin boundary energies; the  
units of KT must match the units of KT.  Both are in keV, by  
default; see B_nu for a discussion of units.  
The result will have dimensions (numberof(HNUB)-1)-by-dimsof(KT).  
The algorithm has an accuracy of 0.2 percent.  The idea is to  
difference an analytic approximation to the integral of B_nu.  
Interpreted function, defined at i0/drat.i   line 983