I=planck(nu,T) Planck's radiation law gives spectral intensity I for a radiation field of temperature T. Input in Hz and K Output in W m^-2 Hz^-1 Sr^-1 To convert to Jy/Sr multiply by 1e26 To convert to intensity per unit wavelength multiply by nu/lambda to get W m^-2 m^-1 Sr^-1 To convert to power emmited per unit surface area multiply by pi to get W m^-2 Hz^-1. To convert to spatial energy density multiply by 4pi/c to get J m^-3 Hz^-1. 1 erg = 1e-7 Joule, cm^2 = 1e4 m^2 so to convert to erg s^-1 cm^-2 Hz^-1 ster^-1 mult by 1e7*1e-4
0001 function I=planck(nu,T) 0002 % I=planck(nu,T) 0003 % 0004 % Planck's radiation law gives spectral intensity I for a 0005 % radiation field of temperature T. 0006 % 0007 % Input in Hz and K 0008 % Output in W m^-2 Hz^-1 Sr^-1 0009 % 0010 % To convert to Jy/Sr multiply by 1e26 0011 % 0012 % To convert to intensity per unit wavelength multiply 0013 % by nu/lambda to get W m^-2 m^-1 Sr^-1 0014 % 0015 % To convert to power emmited per unit surface area 0016 % multiply by pi to get W m^-2 Hz^-1. 0017 % 0018 % To convert to spatial energy density multiply by 0019 % 4pi/c to get J m^-3 Hz^-1. 0020 % 0021 % 1 erg = 1e-7 Joule, cm^2 = 1e4 m^2 0022 % so to convert to erg s^-1 cm^-2 Hz^-1 ster^-1 0023 % mult by 1e7*1e-4 0024 0025 h=6.626e-34; 0026 k=1.38e-23; 0027 c=3e8; 0028 x=(h*nu)./(k*T); 0029 0030 I=(2*h*nu.^3*c^-2)./(exp(x)-1);