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Papers Using Thor

If you have used Thor in a publication and would like to be listed here, please open an issue or pull request on GitHub.

Code Paper

If you use Thor in your research, please cite:

C. Byrohl & D. Nelson (2025). THOR: a GPU-accelerated and MPI-parallel radiative transfer code. arXiv:2507.11603. ADS | arXiv

BibTeX 
@ARTICLE{2025arXiv250711603B,
       author = {{Byrohl}, Chris and {Nelson}, Dylan},
        title = "{THOR: a GPU-accelerated and MPI-parallel radiative transfer code}",
      journal = {arXiv e-prints},
     keywords = {Astrophysics of Galaxies, Instrumentation and Methods for Astrophysics},
         year = 2025,
        month = jul,
          eid = {arXiv:2507.11603},
        pages = {arXiv:2507.11603},
          doi = {10.48550/arXiv.2507.11603},
archivePrefix = {arXiv},
       eprint = {2507.11603},
 primaryClass = {astro-ph.GA},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2025arXiv250711603B},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

Applications

Thor descends from the voroILTIS Monte Carlo radiative transfer code, which operated directly on the Voronoi tessellation of cosmological simulations. Papers using voroILTIS (and its earlier grid-based incarnations) include:

  • N. Truong, M. Markevitch, D. Nelson, & C. Byrohl (2026). Inferring the mass of the circumgalactic medium using X-ray resonant scattering. arXiv:2603.25600. ADS | arXiv.

  • D. Nelson, C. Byrohl, A. Ogorzalek, et al. (2023). Resonant scattering of the O VII X-ray emission line in the circumgalactic medium of TNG50 galaxies. MNRAS, 522, 3665. ADS | arXiv — O VII X-ray line resonant scattering.

  • C. Byrohl & D. Nelson (2023). The cosmic web in Lyman-alpha emission. MNRAS, 523, 5248. ADS | arXiv — diffuse Ly\(\alpha\) cosmic web in TNG50.

  • C. Byrohl, D. Nelson, C. Behrens, et al. (2021). The physical origins and dominant emission mechanisms of Lyman alpha haloes: results from the TNG50 simulation in comparison to MUSE observations. MNRAS, 506, 5129. ADS | arXiv — paper introducing the voroILTIS code in more detail.

  • C. Byrohl & M. Gronke (2020). Variations in shape among observed Lyman-alpha spectra due to intergalactic absorption. A&A, 642, L16. ADS | arXiv — first paper using voroILTIS.

The ILTIS code, developed by C. Behrens and collaborators, is the upstream Lyα RT code; voroILTIS extended it with native support for unstructured Voronoi meshes along with the performance optimizations required to run on full cosmological simulation boxes. Behrens et al. (2019) is the first paper to refer to the code as ILTIS in print; the same code (under earlier names) was used in the prior works listed below:

  • C. Behrens, A. Pallottini, A. Ferrara, S. Gallerani, & L. Vallini (2019). Lyα emission from galaxies in the Epoch of Reionization. MNRAS, 486, 2197. ADS | arXiv — first paper to use the name ILTIS in print.

  • C. Behrens, C. Byrohl, S. Saito, & J. C. Niemeyer (2018). The impact of Lyman-α radiative transfer on large-scale clustering in the Illustris simulation. A&A, 614, A31. ADS | arXiv — first application to Illustris, with the Voronoi mesh converted to an octree grid (predecessor to the natively Voronoi-based voroILTIS).

  • C. Behrens & H. Braun (2014). Inclination dependence of Lyman-α properties in a turbulent disk galaxy. A&A, 572, A74. ADS | arXiv — high-resolution application to an idealized galaxy setup.

  • C. Behrens, M. Dijkstra, & J. C. Niemeyer (2014). Beamed Lyman alpha emission through outflow-driven cavities. A&A, 563, A77. ADS | arXiv — meshless idealized toy-model investigation.

  • C. Behrens & J. C. Niemeyer (2013). Effects of Lyman-α scattering in the IGM on clustering statistics of Lyman-α emitters. A&A, 556, A5. ADS | arXiv — first use of the code that later became ILTIS.