21cm polarisation
Posted: November 13 2017
Hi Anthony and co
I am trying to reproduce the 21cm polarisation power spectra as in https://arxiv.org/pdf/astro-ph/0702600.pdf -Fig. 9. Although it is not immediately evident, from running through the code it seems setting line_reionoization = .true. should produce polarised spectra.
The first question is if this is indeed the case?
If yes, I found that there are several issues with running the (GitHub) version of the code. I have tried both intel (16 and 17) and Gfortran compilers (gcc 7.2.0 ). With default settings (high lmax) the code crashes when solving the ODE's. Running with a debugging flag I find at least one issue in modules.f90 where the array TimeSteps%points runs out of bound (in the subroutine interp_window). Apparently this is not causing the later crash as I learned by patching this problem. Fortunately lowering lmax to 2000 seems to work and does not crash the code. However, now the EE power spectra and ET CMB power spectra are completely off. Producing some weird looking spectrum that is larger then the TT spectrum and resembles a matter or lensing power spectrum more then a CMB power spectrum ( I have attached a plot).
In any case, it seems to overwrite the CMB E-mode polarisation spectrum, but it is not clear with what (it also does not look like the spectrum in Fig. 9 of the aforementioned paper). Any thoughts? Maybe the sources are not overwritten but are added (so it would be the sum of CMB E-mode + 21cm E-modes??).
Also, even if line_reionization is the correct flag, there is no extra file produced for E-modes. I now simply turned off all other Line contributions. I then get a spectrum that looks somewhat similar to the spectrum in Fig. 9, however where the wiggles are much less pronounced (using the same redshift and same window).
Last, I tried to run tensors, but there is no equivalent file produced (the scalCov) that contains tensors. It is not really important right now, but I wondered if there is a way to produce the tensor 21cm polarisation spectra from the code.
Any help would be appreciated.
Best
Daan
EEspectrum_wLineReionizationTrue.pdf[/url]
I am trying to reproduce the 21cm polarisation power spectra as in https://arxiv.org/pdf/astro-ph/0702600.pdf -Fig. 9. Although it is not immediately evident, from running through the code it seems setting line_reionoization = .true. should produce polarised spectra.
The first question is if this is indeed the case?
If yes, I found that there are several issues with running the (GitHub) version of the code. I have tried both intel (16 and 17) and Gfortran compilers (gcc 7.2.0 ). With default settings (high lmax) the code crashes when solving the ODE's. Running with a debugging flag I find at least one issue in modules.f90 where the array TimeSteps%points runs out of bound (in the subroutine interp_window). Apparently this is not causing the later crash as I learned by patching this problem. Fortunately lowering lmax to 2000 seems to work and does not crash the code. However, now the EE power spectra and ET CMB power spectra are completely off. Producing some weird looking spectrum that is larger then the TT spectrum and resembles a matter or lensing power spectrum more then a CMB power spectrum ( I have attached a plot).
In any case, it seems to overwrite the CMB E-mode polarisation spectrum, but it is not clear with what (it also does not look like the spectrum in Fig. 9 of the aforementioned paper). Any thoughts? Maybe the sources are not overwritten but are added (so it would be the sum of CMB E-mode + 21cm E-modes??).
Also, even if line_reionization is the correct flag, there is no extra file produced for E-modes. I now simply turned off all other Line contributions. I then get a spectrum that looks somewhat similar to the spectrum in Fig. 9, however where the wiggles are much less pronounced (using the same redshift and same window).
Last, I tried to run tensors, but there is no equivalent file produced (the scalCov) that contains tensors. It is not really important right now, but I wondered if there is a way to produce the tensor 21cm polarisation spectra from the code.
Any help would be appreciated.
Best
Daan
EEspectrum_wLineReionizationTrue.pdf[/url]