def get_luminosity_distance(redshift):
    '''finds luminosity distance'''
    lum_dist = cosmo.luminosity_distance(redshift)
    tmp = str(lum_dist)
    tmp = tmp.replace("Mpc","")
    tmp = float(tmp)
    return tmp*3.09*10**22
    print lum_dist

def get_alpha(s1,s2,v1,v2):
    '''gets alpha from two flux densities'''
    top = math.log10(s1/s2)
    bottom = math.log10(v2/v1)
    return top/bottom

def get_luminosity(D_l,z,a,nu1,nu2,Sv2):
    '''gets luminosity from alpha'''
    Sv2 = (Sv2/1000)*CF
    lum = (4*math.pi*((D_l**2)))*(1/((1+z)**(1+a)))*((nu1/nu2)**a)*(Sv2)
    return lum