oLIMpus: An Effective Model for Line Intensity Mapping Auto- and Cross- Power Spectra in Cosmic Dawn and Reionization
oLIMpus is an actively maintained and expanding Python-based framework for simulating line intensity mapping (LIM) signals during the epoch of reionization (EoR). It provides a fast and efficient way to compute non-linear power spectra of star-forming lines, and generates both coeval boxes and lightcones.
The 21-cm signal is introduced by interfacing oLIMpus with Zeus21, a public code for 21-cm signal modeling at cosmic dawn. A version of Zeus21 is included in this repository as a submodule. Note that the original Zeus21 currently models only the power spectrum during cosmic dawn; support for the reionization era is under active development.
We recommend creating a new virtual environment based on python 3.10 when installing the code, to avoid dependency conflicts.
If you don't have CLASS installed in your laptop, first run these lines (modifying the Makefile to your gcc as needed):
git clone https://github.com/lesgourg/class_public.git class
cd class/
make
cd python/
python setup.py install --user
To install oLIMpus, if you have conda in your laptop you can simply run the setup.sh file through
chmod 755 setup_env.sh
./setup_env.shThis will create the conda environment oLIMpus, install the code and all dependencies, and install jupyter to run the notebooks.
Otherwise, you can run the installation in the folder where you downloaded the repository, through:
pip install .
⚠️ Note
oLIMpus includes its own version of Zeus21 as a submodule, last updated in June 2025; later versions of Zeus21 may introduce changes that are not compatible with this code. If, for some reason, you want to run oLIMpus with a different Zeus21 version, contact us to verify differences between various versions.
The authors are committed to keep the two codes updated and compatible once new milestones are reached on one side or the other.
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inputs_LIM.py
Set the input parameters to compute the line luminosity and to set the properties of the power spectrum (e.g., linear/quadratic lognormal, with/without shot noise, with/without RSD). -
LIM_luminosities.py
Default models for the line luminoisty-SFR or -halo mass relations. Default includes models for OIII, OII, Ha, Hb, CII, CO21. -
LIM_modeling.py
Compute the quantities needed to setup the model (e.g., the line luminosity density and the coefficients of the lognormal). -
correlations_LIM.py
Computes auto- and cross-power spectra of various emission lines, including astrophysical nonlinearities, redshift-space distortions, shot noise. -
analysis.py
Fiducial setup, create a collective class to run oLIMpus and Zeus21 and get consistent outputs. -
maps_LIM.py
Functions required to produce coeval maps and lightcones. -
zeus21_local/zeus21/(submodule)
Modified version ofZeus21used to compute 21-cm power spectra and fields during cosmic dawn (reionization modeling in progress). For details, see Zeus21 official documentation.
The following notebooks and scripts will help you get started:
#1 oLIMpus.ipynb– Compute and visualize the LIM and 21-cm auto- and cross-power spectra#2 boxes_and_lightcones.ipynb– Create coeval boxes and lightcones#3 explore_parameters.ipynb– Explore how the LIM power spectrum depends on different parameters
📌 You can find all tutorials in the
Tutorials/folder.
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Libanore, Muñoz and Kovetz, oLIMpus: An Effective Model for Line Intensity Mapping Auto- and Cross- Power Spectra in Cosmic Dawn and Reionization, arXiv:2507.15922
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Libanore, Kovetz, Muñoz, Sklansky, Thélie, A New Boundary Condition on Reionization,arXiv:2509.08886
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Muñoz, An Effective Model for the Cosmic-Dawn 21-cm Signal, arXiv:2302.08506
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Sklanksy et al., In preparation
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Cruz, Muñoz, Sabti and Kamionkowski, The First Billion Years in Seconds: An Effective Model for the 21-cm Signal with Population III Stars, arXiv:2407.18294
For questions, suggestions, or help using the code, please contact:
Sarah Libanore
📧 libanore@bgu.ac.il
⭐ If you use oLIMpus in your work, please cite the relevant papers!