| B_nu 
 | 
             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  
 |