cosmology.py 文件源码

def age(self, z):
        """
        Cosmic time (age) at redshift z.

        Parameters
        ----------
        z : `~numpy.ndarray`
            Redshift

        Returns
        -------
        age : `~numpy.ndarray`
            Age of the universe (cosmic time) at the given redshift.
            Unit: [Gyr]

        References: Ref.[thomas2000],Eq.(18)
        """
        z = np.asarray(z)
        t_H = self.hubble_time
        t = ((2*t_H / 3 / np.sqrt(1-self.Om0)) *
             np.arcsinh(np.sqrt((1/self.Om0 - 1) / (1+z)**3)))
        return t