| Name: | Extragalactic Point Sources |
|---|---|
| Author: | Shikhar Mittal |
| Paper: | Mittal et al (2024) |
Use this code to generate the foregrounds due to extragalactic point sources.
A cosmological global 21-cm signal hides under foregrounds due to galactic and extragalactic emissions. These foregrounds can easily be 4 to 5 orders of magnitude higher than the signal of interest. For a reliable inference, it is important to accurately model these foregrounds. While we have a reasonable understanding of galactic emission (typically fit as a log-log polynomial), we do not understand the extragalactic contributions. This package models the foregrounds due to extragalactic radio sources.
Read more about it in the paper Mittal et al (2024).
This package can be installed as
pip install epspyIt is recommended to work on a Python version > 3.8. Packages required are
The code is run in two main steps:
- Assign the point sources flux densities (at a chosen reference frequency) and spectral indices.
- Then generate the sky maps at desired frequencies of observation.
The following code captures the main functionalities of this package.
from epspy import meps
#Step-1 initialise the object with default settings
obj = meps.eps()
#Step-2 generate the data at the reference frequency
obj.ref_freq()
#Step-3 generate the sky maps at multiple frequencies as well as their sky average
obj.gen_freq()
#Step-4 finally, generate a sky-averaged spectrum vs frequency figure
obj.visual()Save the above code as (say) eg_script.py and run it as
python eg_script.pyRunning the above will generate several files. The terminal messages will guide you to these output files. The most important of all files of your interest will be Tb_nu_map.npy. To visualise your outputs use the function visual(). Refer to the documentation for more details. To learn about the physics of this package see our paper.
The default values in this package have been chosen such that the users can run their scripts on a PC. Since modern PCs have at least 4 cores, for a better performance, one could also run eg_script.py parallelly as
mpirun -np 4 python eg_script.pyIn general, and for more realistic flux density ranges and high-resolution maps, it is recommended to use the code on high-performance clusters.
For more details on the working of the package and understanding the output files refer to the documentation.
The software is free to use on the MIT open-source license. If you use the software then please consider citing Mittal et al (2024).
In case of any confusion or suggestions for improvement please do not hesitate to contact me.