Package: rmnest
RMNestRMNestis an open source python package for estimating both standard and generalised
rotation measures via direct fits to StokesQ,UandVspectra.InstallationThe latest release ofRMNestcan be installed fromPyPiby running
the followingpipinstallrmnestNote that while a working installation of the PSRCHIVE Python-3 bindings is
not necessary for usingRMNest, it is strongly recommended.RequirementsThe following packages are required to runningRMNest.numpy: Array manipulationmatplotlib: Modules for plottingbilby: Inference calculations frameworkdynesty: Modules for nested samplingUsageRMNestcan be run directly from the command line within usingrmnest.
As an example, the below command would run a standard rotation-measure fit on the provided test data after frequency-averaging to 128 channels
within a [pulse] phase window between phase = 0.45 to 0.55rmnestarchivetest/2020-03-16-18\:12\:00.calib.ST-otest/output/-ltestrun--window0.45:0.55-f128Alternatively, fitting for the generalised form of Faraday rotation, sometimes referred to as Faraday conversion
(see e.g.Kennett & Melrose 1998), can be performed
by adding the--gfrand--free_alphaflags asrmnest<archive>.ar-o<outdir>-ltestrun--window0.45:0.55--gfr--free_alphaOmitting the--free_alphaflag will result in the spectral exponent being fixed to 3. Details of the underlying phenomenological model can be
found in a technical document byLower (2021).The likelihood and Faraday rotation models, as well as the generalRMFitclass infit_RM.py, can also be imported like any other API.Issues and ContributingIf you encounter any issues withRMNest, or have in mind a feature that
currently does not exist, then you can contribute by openning aGithub Issueand outlining the feature.Referencing RMNestIf you make use ofRMNestin your research, we would greatly appreciate it if you
cite both the ASCL entry (Lower et al. 2022)
and the papers behind its development.@software{2022ascl.soft04008L,
       author = {{Lower}, Marcus E. and {Kumar}, Pravir and {Shannon}, Ryan M.},
        title = "{RMNest: Bayesian approach to measuring Faraday rotation and conversion in radio signals}",
     keywords = {Software},
 howpublished = {Astrophysics Source Code Library, record ascl:2204.008},
         year = 2022,
        month = apr,
          eid = {ascl:2204.008},
        pages = {ascl:2204.008},
archivePrefix = {ascl},
       eprint = {2204.008},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2022ascl.soft04008L},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}For standard rotation measure fitting, then
please citeBannister et al. (2019).@ARTICLE{2019Sci...365..565B,
       author = {{Bannister}, K.~W. and {Deller}, A.~T. and {Phillips}, C. and {Macquart}, J. -P. and {Prochaska}, J.~X. and {Tejos}, N. and {Ryder}, S.~D. and {Sadler}, E.~M. and {Shannon}, R.~M. and {Simha}, S. and {Day}, C.~K. and {McQuinn}, M. and {North-Hickey}, F.~O. and {Bhandari}, S. and {Arcus}, W.~R. and {Bennert}, V.~N. and {Burchett}, J. and {Bouwhuis}, M. and {Dodson}, R. and {Ekers}, R.~D. and {Farah}, W. and {Flynn}, C. and {James}, C.~W. and {Kerr}, M. and {Lenc}, E. and {Mahony}, E.~K. and {O'Meara}, J. and {Os{\l}owski}, S. and {Qiu}, H. and {Treu}, T. and {U}, V. and {Bateman}, T.~J. and {Bock}, D.~C. -J. and {Bolton}, R.~J. and {Brown}, A. and {Bunton}, J.~D. and {Chippendale}, A.~P. and {Cooray}, F.~R. and {Cornwell}, T. and {Gupta}, N. and {Hayman}, D.~B. and {Kesteven}, M. and {Koribalski}, B.~S. and {MacLeod}, A. and {McClure-Griffiths}, N.~M. and {Neuhold}, S. and {Norris}, R.~P. and {Pilawa}, M.~A. and {Qiao}, R. -Y. and {Reynolds}, J. and {Roxby}, D.~N. and {Shimwell}, T.~W. and {Voronkov}, M.~A. and {Wilson}, C.~D.},
        title = "{A single fast radio burst localized to a massive galaxy at cosmological distance}",
      journal = {Science},
     keywords = {ASTRONOMY, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics},
         year = 2019,
        month = aug,
       volume = {365},
       number = {6453},
        pages = {565-570},
          doi = {10.1126/science.aaw5903},
archivePrefix = {arXiv},
       eprint = {1906.11476},
 primaryClass = {astro-ph.HE},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2019Sci...365..565B},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}If you usedRMNestfor generalised Faraday rotation measure fitting, please include
a citation toLower (2021).@ARTICLE{2021arXiv210809429L,
       author = {{Lower}, Marcus E.},
        title = "{A phenomenological model for measuring generalised Faraday rotation}",
      journal = {arXiv e-prints},
     keywords = {Astrophysics - High Energy Astrophysical Phenomena},
         year = 2021,
        month = aug,
          eid = {arXiv:2108.09429},
        pages = {arXiv:2108.09429},
archivePrefix = {arXiv},
       eprint = {2108.09429},
 primaryClass = {astro-ph.HE},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2021arXiv210809429L},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}