CROSS_CMBFAST 
Code based on CMBFAST4.5.1 by Seljak & Zaldarriaga 

Welcome to CROSS_CMBFASTThis code is an extension of CMBFAST4.5.1 to compute the ISWcorrelation power spectrum and the 2point angular ISWcorrelation function for a given galaxy window function. It includes dark energy models specified by a constant equation of state (w) or a linear parameterization in the scale factor (w0,wa) and a constant sound speed (c2de). For reference see astroph/0504115, while for a detailed description of the ISWcorrelation equations implemented see astroph/0506396. The ISW computation is limited to flat geometry. Differently from the original CMBFAST4.5 version dark energy perturbations are implemented for a general dark energy fluid specified by w(z) and c2de in synchronous gauge (see for instance Eq.79 in Bean and Dore astroph/0307100). For time varying dark energy models it is suggested not to cross the w=1 line, as Dr. Wenkman says: "never cross the streams", bad things can happen. Galaxy Selection FunctionThe code allows to specify the galaxy window function. Two possibilities are implemented: 1) a standard window function ( A z^m exp[(z/z0)^beta] ) normalized to unity with input parameters median redshift zmed (=1.41 z0) and the slopes m and beta. A bit of care is necessary for the normalization (see remarks); 2) Luminous Red Galaxies window function from SDSS. OutputThe output consists of two files, the angular ISWcorrelation function in microK (theta,C_Tg(theta)) and the power spectra in multipole space, the second column is the ISWcorrelation power spectrum l(l+1)/2pi C_l(Tg) and the last column is the mattermatter angular power spectrum l(l+1)/2pi C_l(gg), in order to get the galaxygalaxy power spectrum you need to multiply by your preferred constant bias value or you need to implement the model bias in the ISWcorrelation computation (see remarks). Other columns are standard CMB spectra as in CMBFAST. Output data are normalized as WMAP3 at k=0.002 Mpc^1 (A_s is an input parameter). Remarks
The code can be easily modified for studying ISWcorrelation
in more complicate models (modified gravity, time varying neutrino mass,
coupled quintessence, etc..). In order to implement a scale and time
dependent bias you need to modify the ISWcorrelation computation in
cmbcrossflat.F. If you want to use a nonstandard selection function
you can modify it in subcross.F. and change the normalization
accordingly, you can use a numerical integration which I left for such
a case. On the other hand if you want to use a very broad standard
selection function be careful with the value of beta you plug in, if
beta ~ 0 remember that the Gamma function blows up, while you are just using
a power low selection function whose integral depends on the maximmum
redshift of the survey.
Dowload hereUpdates
How to run CROSS_CMBfast: gunzip CROSS_CMBFAST.tar.gz


