cnb-anisotropies

This repository contains code that accompanies the papers Multi-Messenger Astrophysics with the Cosmic Neutrino Background and Impact of Warm Dark Matter on the Cosmic Neutrino Background Anisotropies. The perturbations.c and perturbations.h files contain modifications made to the corresponding CLASS files to extract neutrino perturbation information. The notebook file computes and shows, for example, the CNB anisotropies and the corresponding expected neutrino capture rate variations for the PTOLEMY experiment, as shown in the maps below:

The cnb_utils.py file contains utility functions used to compute CNB anisotropies for both papers. The wdm_cl.py and wdm_pk.py files contain code that makes the figures for the warm dark matter (WDM) paper.

Note: In the WDM paper, we use synchronous gauge when specifying the CLASS parameters because we noticed that the power spectra in the WDM case in the limit that m_ncdm is large deviates significantly from the CDM power spectra in Newtonian gauge when we expect them to agree. In synchronous gauge, however, the results agree well and thus gives us sensible results for the CNB anisotropies.

Prerequisites

Install CONCEPT on to your machine with the command

bash <(wget -O- --no-check-certificate https://raw.githubusercontent.com/jmd-dk/concept/v1.0.1/install)

Then in the /path/to/concept_installation/python/bin/ directory, run

./pip install notebook 
./pip install healpy

Usage

To download the code in this repository to your local machine, do

git clone https://github.com/gemyxzhang/cnb-anisotropies

Then replace the files at /path/to/concept_installation/class/source/perturbations.c and /path/to/concept_installation/class/include/perturbations.h with the perturbations.c and perturbations.h files downloaded from this repository.

To recompile CONCEPT with the new perturbations files, do

cd /path/to/concept_installation/class 
make clean 
PYTHON=/path/to/concept_installation/python/bin/python3.8 make

Note that the python3.8 in the above command should be replaced with the python version available in your local CONCEPT install.

To run the cnb_utils.py, figures.ipynb, wdm_cl.py and wdm_pk.py files from this repository, place them into /path/to/concept_installation/class/notebooks/. To run the notebook file, you can open Jupyter Notebooks by

/path/to/concept_installation/python/bin/jupyter notebook

Remote access

For running the Jupyter Notebooks on remote clusters, run

/path/to/concept_installation/python/bin/jupyter notebook --no-browser --ip=127.0.0.1 --port=7095

and then in a new terminal window on your local machine, run

ssh -N -f -L 7095:localhost:7095 <usernanme>@<hostname>

Copying and pasting the URL from the Jupyter server output on the cluster (http://127.0.0.1:7095/?token=...) into a local broswer allows you to access the figures.ipynb code in your browser.