This code is an extension of CMBFAST4.5.1 (no longer distributed) by U. Seljak & M. Zaldarriaga to compute the ISW-correlation power spectrum and the 2-point angular ISW-correlation 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 (\\(w_0\\), \\(w_a\\)) and a constant sound speed (c2de). For reference see astro-ph\/0504115<\/strong><\/a>, while for a detailed description of the ISW-correlation equations implemented see astro-ph\/0506396<\/strong><\/a>. 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. (7)-(9) in Bean and Dore astro-ph\/0307100<\/strong><\/a>). For time varying dark energy models it is suggested not to cross the \\(w=-1\\) line, as Dr. Wenkman says: \u201cnever cross the streams\u201d, bad things can happen.<\/p>\n\n\n\n The code allows to specify the galaxy window function. Two possibilities are implemented: 1) a standard window function ( \\(A z^m e^{-(z\/z_0)^{\\beta}}\\) ) normalized to unity with input parameters median redshift \\(z_{med}\\) ( \\(=1.41 z_0\\) ) 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.<\/p>\n\n\n\n The output consists of two files, the angular ISW-correlation function in \\(\\mu\\)K ( \\(\\theta\\), \\(C_{Tg}(\\theta)\\) ) and the power spectra in multipole space, the second column is the ISW-correlation power spectrum \\(l(l+1)\/2\\pi\\, C_{l}^{(Tg)}\\) and the last column is the matter-matter angular power spectrum \\(l(l+1)\/2\\pi\\, C_{l}^{(gg)}\\), in order to get the galaxy-galaxy power spectrum you need to multiply by your preferred constant bias value or you need to implement the model bias in the ISW-correlation 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).<\/p>\n\n\n\n The code can be easily modified for studying ISW-correlation 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 ISW-correlation computation in cmbcrossflat.F. If you want to use a non-standard 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.<\/p>\n\n\n\n modify the Makefile for your compiler and run <\/p>\n\n\n\n before running the executable remember to create the Bessel function file and call it jl.dat<\/p>\n\n\n\n output files are stored in the directory output, in the package I left two test input files: wconst.ini and wvar.ini. <\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Code Description This code is an extension of CMBFAST4.5.1 (no longer distributed) by U. Seljak & M. Zaldarriaga to compute the ISW-correlation power spectrum and the 2-point angular ISW-correlation 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 … <\/p>\nGalaxy Selection Function<\/h3>\n\n\n\n
Output<\/h3>\n\n\n\n
Remarks<\/h3>\n\n\n\n
Download: CROSS_CMBfast1.2.tar.gz<\/a><\/h4>\n\n\n\n
How to run the code<\/h3>\n\n\n\n
tar -zxvf CROSS_CMBFAST.tar\n<\/pre>\n\n\n\n
mkdir output<\/pre>\n\n\n\n
make<\/pre>\n\n\n\n
jlgen (.\/jlgen if you use bash)<\/pre>\n\n\n\n
jlgen (.\/jlgen if you use bash)<\/pre>\n\n\n\n
cmb<\/pre>\n\n\n\n
cmb < wvar.ini<\/pre>\n\n\n\n