function snia_K01, m 
M_s = 459040.5 ;mass of my ssp (mass of star particle in M_sun)
A = 0.22038
frac_b = 0.05
beta = 1.3
 if 2.*m lt 3 then x = 3. else x=2.*m
 return, M_s*24*A*frac_b*(-1./(beta + 2))*m^2.*((m+8.)^(-(beta + 2))-x^(-(beta + 2)))/alog(10.0)/alog(10.0)
end