code: def peak_energy(self):
          
  
          # Eq. 6 in Massaro et al. 2004
          # (http://adsabs.harvard.edu/abs/2004A%26A...413..489M)
  
          return self.piv.value * pow(10, ((2 + self.alpha.value) * np.log(10)) / (2 * self.beta.value))
docs: Returns the peak energy in the nuFnu spectrum
  
          :return: peak energy in keV