1.Introduction :
CAMB (Code for Anisotropies in Microwave Background) is a numerical tool designed to best describe anisotropies in microwave background, i.e the first light emitted by the Universe 380.000 years after the Big-bang. This code is avalaible on cosmologist.info website. You will able to find also the theoretical part and the implemented numerical method.
2.Use of CAMB :
Once the archive decompressed, look at the compilation. We can build 2 types of executable : "camb" et "camb_fits". The first is the basics version of the code, which only generates raw output data files. Among these files, the most important is the one which contains temperature as a function of the multipole "l" parameter : "test_scalCls.dat" file by default.
The second one allows to get, with in addition of the previous ones, a FITS formatted output file : "test_scalCls.fits" file by default.
Depending on the version of the code you have, you may experience problems with compilation. For any questions, you can subscribe to the following dedicated forum : cosmocoffee.info, and post into the "Computers and software" part.
3.Results examples :
Below a comparison of two power angular spectra got with CAMB and the second one Hi-CLASS.
The (CAMB)
represents the standard model
ΛCDM, while the second (Hi-CLASS) is coming from Horndeski's models.
For those of you who have already used gnuplot, here is a script to plot power spectra:
You can notice the logarithmic scale for 0 < l < 200 and linear scale for 200 < l < 2000.
4.Tutorial on CAMB :
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