*** Cross-power spectrum of CMB lensing potential and the Rees-Sciama effect, Q(l) ***
April 6, 2012: E.Komatsu

This program reads in the non-linear power spectrum table generated by "generate_pkz" or "generate_pkz3pt" (also available on CRL), and calculates the cross-correlation power spectrum of the CMB lensing potential and the Rees-Sciama (or Integrated Sachs-Wolfe effect on large scales) effect:

Q(l) = 2 \int_0^z* dz [r(z*)-r(z)]/[r(z*)r^3(z)] [dPpsi(k,z)/dz]_{k=l/r(z)}

where r(z) is the comoving distance, z*=1090 is the redshift of the photon decoupling epoch, and Ppsi(k,z) is the power spectrum of Newtonian gravitational potential.

This code reads in the non-linear power spectrum of density fluctuations (not potential) computed in four ways:

1. 3rd-order perturbation theory
2. Halofit [Smith et al. (2003)]
3. Ma et al. (1999)
4. Peacock & Dodds (1996)

The output contains:
(1st column) multipole, l
(2nd column) Q(l)


- To compile and use the program, edit Makefile and simply "make"
- It will generate an executable called "compute_ql"
- Running "compute_ql" generates a file called "ell_ql_***.txt" (where *** indicates which non-linear model is used), which contains:

(1st column) multipole, l
(2nd column) Q(l)