21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy
Neural network (NN) emulators of the global 21 cm signal need an emulation error much less than the observational noise in order to be used to perform unbiased Bayesian parameter inference. To this end, we introduce 21cmLSTM —a long short-term memory (LSTM) NN emulator of the global 21 cm signal tha...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2024-01-01
|
| Series: | The Astrophysical Journal |
| Online Access: | https://doi.org/10.3847/1538-4357/ad8b20 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850266448828563456 |
|---|---|
| author | J. Dorigo Jones S. M. Bahauddin D. Rapetti J. Mirocha J. O. Burns |
| author_facet | J. Dorigo Jones S. M. Bahauddin D. Rapetti J. Mirocha J. O. Burns |
| author_sort | J. Dorigo Jones |
| collection | DOAJ |
| description | Neural network (NN) emulators of the global 21 cm signal need an emulation error much less than the observational noise in order to be used to perform unbiased Bayesian parameter inference. To this end, we introduce 21cmLSTM —a long short-term memory (LSTM) NN emulator of the global 21 cm signal that leverages the intrinsic correlation between frequency channels to achieve exceptional accuracy compared to previous emulators, which are all feedforward, fully connected NNs. LSTM NNs are a type of recurrent NN designed to capture long-term dependencies in sequential data. When trained and tested on the same simulated set of global 21 cm signals as the best previous emulators, 21cmLSTM has an average relative rms error of 0.22%—equivalently 0.39 mK—and comparably fast evaluation time. We perform seven-dimensional Bayesian parameter estimation analyses using 21cmLSTM to fit global 21 cm signal mock data with different adopted observational noise levels, σ _21 . The posterior 1 σ rms error is ≈three times less than σ _21 for each fit and consistently decreases for tighter noise levels, showing that 21cmLSTM can sufficiently exploit even very optimistic measurements of the global 21 cm signal. We have made the emulator, code, and data sets publicly available so that 21cmLSTM can be independently tested and used to retrain and constrain other 21 cm models. |
| format | Article |
| id | doaj-art-6fc048fc7cf9432c8faf6c3b7ed3831f |
| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-6fc048fc7cf9432c8faf6c3b7ed3831f2025-08-20T01:54:11ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0197711910.3847/1538-4357/ad8b2021cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented AccuracyJ. Dorigo Jones0https://orcid.org/0000-0002-3292-9784S. M. Bahauddin1https://orcid.org/0000-0003-0016-5377D. Rapetti2https://orcid.org/0000-0003-2196-6675J. Mirocha3https://orcid.org/0000-0002-8802-5581J. O. Burns4https://orcid.org/0000-0002-4468-2117Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado Boulder , CO 80309, USA ; johnny.dorigojones@colorado.eduLaboratory for Atmospheric and Space Physics, University of Colorado , Boulder, CO 80303, USACenter for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado Boulder , CO 80309, USA ; johnny.dorigojones@colorado.edu; NASA Ames Research Center , Moffett Field, CA 94035, USA; Research Institute for Advanced Computer Science, Universities Space Research Association , Washington, DC 20024, USAJet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA; California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USACenter for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado Boulder , CO 80309, USA ; johnny.dorigojones@colorado.eduNeural network (NN) emulators of the global 21 cm signal need an emulation error much less than the observational noise in order to be used to perform unbiased Bayesian parameter inference. To this end, we introduce 21cmLSTM —a long short-term memory (LSTM) NN emulator of the global 21 cm signal that leverages the intrinsic correlation between frequency channels to achieve exceptional accuracy compared to previous emulators, which are all feedforward, fully connected NNs. LSTM NNs are a type of recurrent NN designed to capture long-term dependencies in sequential data. When trained and tested on the same simulated set of global 21 cm signals as the best previous emulators, 21cmLSTM has an average relative rms error of 0.22%—equivalently 0.39 mK—and comparably fast evaluation time. We perform seven-dimensional Bayesian parameter estimation analyses using 21cmLSTM to fit global 21 cm signal mock data with different adopted observational noise levels, σ _21 . The posterior 1 σ rms error is ≈three times less than σ _21 for each fit and consistently decreases for tighter noise levels, showing that 21cmLSTM can sufficiently exploit even very optimistic measurements of the global 21 cm signal. We have made the emulator, code, and data sets publicly available so that 21cmLSTM can be independently tested and used to retrain and constrain other 21 cm models.https://doi.org/10.3847/1538-4357/ad8b20 |
| spellingShingle | J. Dorigo Jones S. M. Bahauddin D. Rapetti J. Mirocha J. O. Burns 21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy The Astrophysical Journal |
| title | 21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy |
| title_full | 21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy |
| title_fullStr | 21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy |
| title_full_unstemmed | 21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy |
| title_short | 21cmlstm: A Fast Memory-based Emulator of the Global 21 cm Signal with Unprecedented Accuracy |
| title_sort | 21cmlstm a fast memory based emulator of the global 21 cm signal with unprecedented accuracy |
| url | https://doi.org/10.3847/1538-4357/ad8b20 |
| work_keys_str_mv | AT jdorigojones 21cmlstmafastmemorybasedemulatoroftheglobal21cmsignalwithunprecedentedaccuracy AT smbahauddin 21cmlstmafastmemorybasedemulatoroftheglobal21cmsignalwithunprecedentedaccuracy AT drapetti 21cmlstmafastmemorybasedemulatoroftheglobal21cmsignalwithunprecedentedaccuracy AT jmirocha 21cmlstmafastmemorybasedemulatoroftheglobal21cmsignalwithunprecedentedaccuracy AT joburns 21cmlstmafastmemorybasedemulatoroftheglobal21cmsignalwithunprecedentedaccuracy |