In [6]:

    

import numpy as np
%matplotlib inline
import matplotlib.pyplot as plt


    

In [7]:

    

from astropy.cosmology import Planck13 as cosmo


    

In [8]:

    

percent = lambda z, deltaz: 5.0 / np.log(10) *(cosmo.luminosity_distance(z + deltaz) - cosmo.luminosity_distance(z))/cosmo.luminosity_distance(z)


    

In [9]:

    

zvals = np.arange(0., 1.2, 0.01)
fig, ax = plt.subplots()
ax.plot(zvals, percent(zvals, 0.04*(1.+zvals)),'b',label='photoz_error=0.04')
ax.plot(zvals, percent(zvals, 0.01*(1.+zvals)),'r',label='photoz_error=0.01')
ax.axhline(0.1, color='k', lw=2.)
ax.grid(True)
ax.set_ylim(ymax=1.)
ax.set_ylabel(r'$\sigma_{mu}$')
ax.set_xlabel(r'$z$')


    

    




/usr/local/manual/anaconda/lib/python2.7/site-packages/astropy/units/quantity.py:757: RuntimeWarning: divide by zero encountered in true_divide
  return np.true_divide(self, other)






    
Out[9]:





<matplotlib.text.Text at 0x1007353d0>