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lesgourg / class_public

Public repository of the Cosmic Linear Anisotropy Solving System (master for the most recent version of the standard code; GW_CLASS to include Cosmic Gravitational Wave Background anisotropies; classnet branch for acceleration with neutral networks; ExoCLASS branch for exotic energy injection; class_matter branch for FFTlog)
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Reheating modules #438

Open shan1525 opened 3 years ago

shan1525 commented 3 years ago

Dear class developers and class experts, I am in the learning process of class. I wanted to work on the reheating modules of class for my work. I searched for the equation of state of reheating, it's temperature and other reheating parameters in the source folder of class. I mainly searched in primordial.c , thermodynamics.c, background.c and perturbations.c. And due to the beautiful interface of class I searched all the modules for the word reheating. But I couldn't find any one. I saw N_dark and other degrees of freedom. But I was unable to find any reheating parameters. I am sorry for asking such a silly question but can anyone tell me where these parameters are defined in the class. That would be very helpful to me. You guys have always been kind to answer our queries. Or, please tell me that it is there and I have to look carefully.

Thanks in advance, with the best regards, shan.

ThomasTram commented 3 years ago

Hi Shan

I think you are referring to the paper 1606.09199. In that paper, we used the ASPIC library to compute the primordial spectrum including reheating. CLASS cannot do it by itself, but it is possible to call an external program and have it return the primordial scalar- and tensor-powerspectrum. To do that, we wrote a small Fortran code (100 lines I think) that would take input parameters (from CLASS) from the command line, call the relevant ASPIC functions and finally print this table to stdout which would then be read by CLASS. So it is doable, but it is not a simple project...

Cheers, Thomas