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 957  

             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 981