Redshift-space distortions

Pylians provides the routine pos_redshift_space to displace particle positions from real-space to redshift-space. The arguments of that function are:

  • pos. This is an array with the co-moving positions of the particles. Should be float numpy array. Notice that this array will be overwritten with the positions of the particles in redshift-space. So if you want to keep the positions of the original particles, is better to pass a copy of this array: e.g. pos_RSD = np.copy(pos). Units should be Mpc/h.

  • vel. This is an array with the peculiar velocities of the particles. Should be a float numpy array. Units should be km/s

  • BoxSize. Size of the simulation box. Units should be Mpc/h

  • Hubble. Value of the Hubble constant at redshift redshift. Units should be (km/s)/(Mpc/h).

  • redshift. The considered redshift.

  • axis. Redshift-space distortions are going to be place along the x-(axis=0), y-(axis=1) or z-(axis=2) axis.

import redshift_space_library as RSL

# move particles to redshift-space. After this call, pos will contain the
# positions of the particles in redshift-space
RSL.pos_redshift_space(pos, vel, BoxSize, Hubble, redshift, axis)