Inferring IGM parameters from the redshifted 21-cm Power Spectrum using Artificial Neural Networks

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Auteurs principaux: Choudhury, Madhurima, Ghara, Raghunath, Zaroubi, Saleem, Ciardi, Benedetta, Koopmans, Leon V. E., Mellema, Garrelt, Shaw, Abinash Kumar, Acharya, Anshuman, Iliev, I. T., Ma, Qing-Bo, Giri, Sambit K.
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Publié: 2024
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author Choudhury, Madhurima
Ghara, Raghunath
Zaroubi, Saleem
Ciardi, Benedetta
Koopmans, Leon V. E.
Mellema, Garrelt
Shaw, Abinash Kumar
Acharya, Anshuman
Iliev, I. T.
Ma, Qing-Bo
Giri, Sambit K.
author_facet Choudhury, Madhurima
Ghara, Raghunath
Zaroubi, Saleem
Ciardi, Benedetta
Koopmans, Leon V. E.
Mellema, Garrelt
Shaw, Abinash Kumar
Acharya, Anshuman
Iliev, I. T.
Ma, Qing-Bo
Giri, Sambit K.
contents The high redshift 21-cm signal promises to be a crucial probe of the state of the intergalactic medium (IGM). Understanding the connection between the observed 21-cm power spectrum and the physical quantities intricately associated with the IGM is crucial to fully understand the evolution of our Universe. In this study, we develop an emulator using artificial neural network (ANN) to predict the 21-cm power spectrum from a given set of IGM properties, namely, the bubble size distribution and the volume averaged ionization fraction. This emulator is implemented within a standard Bayesian framework to constrain the IGM parameters from a given 21-cm power spectrum. We compare the performance of the Bayesian method to an alternate method using ANN to predict the IGM parameters from a given input power spectrum, and find that both methods yield similar levels of accuracy, while the ANN is significantly faster. We also use this ANN method of parameter estimation to predict the IGM parameters from a test set contaminated with noise levels expected from the SKA-LOW instrument after 1000 hours of observation. Finally, we train a separate ANN to predict the source parameters from the IGM parameters directly, at a redshift of $z=9.1$, demonstrating the possibility of a non-analytic inference of the source parameters from the IGM parameters for the first time. We achieve high accuracies, with R2-scores ranging between $0.898-0.978$ for the ANN emulator and between $0.966-0.986$ and $0.817-0.981$ for the predictions of IGM parameters from 21-cm power spectrum and source parameters from IGM parameters, respectively. The predictions of the IGM parameters from the Bayesian method incorporating the ANN emulator leads to tight constraints with error bars around $\pm{0.14}$ on the IGM parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2407_03523
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Inferring IGM parameters from the redshifted 21-cm Power Spectrum using Artificial Neural Networks
Choudhury, Madhurima
Ghara, Raghunath
Zaroubi, Saleem
Ciardi, Benedetta
Koopmans, Leon V. E.
Mellema, Garrelt
Shaw, Abinash Kumar
Acharya, Anshuman
Iliev, I. T.
Ma, Qing-Bo
Giri, Sambit K.
Cosmology and Nongalactic Astrophysics
The high redshift 21-cm signal promises to be a crucial probe of the state of the intergalactic medium (IGM). Understanding the connection between the observed 21-cm power spectrum and the physical quantities intricately associated with the IGM is crucial to fully understand the evolution of our Universe. In this study, we develop an emulator using artificial neural network (ANN) to predict the 21-cm power spectrum from a given set of IGM properties, namely, the bubble size distribution and the volume averaged ionization fraction. This emulator is implemented within a standard Bayesian framework to constrain the IGM parameters from a given 21-cm power spectrum. We compare the performance of the Bayesian method to an alternate method using ANN to predict the IGM parameters from a given input power spectrum, and find that both methods yield similar levels of accuracy, while the ANN is significantly faster. We also use this ANN method of parameter estimation to predict the IGM parameters from a test set contaminated with noise levels expected from the SKA-LOW instrument after 1000 hours of observation. Finally, we train a separate ANN to predict the source parameters from the IGM parameters directly, at a redshift of $z=9.1$, demonstrating the possibility of a non-analytic inference of the source parameters from the IGM parameters for the first time. We achieve high accuracies, with R2-scores ranging between $0.898-0.978$ for the ANN emulator and between $0.966-0.986$ and $0.817-0.981$ for the predictions of IGM parameters from 21-cm power spectrum and source parameters from IGM parameters, respectively. The predictions of the IGM parameters from the Bayesian method incorporating the ANN emulator leads to tight constraints with error bars around $\pm{0.14}$ on the IGM parameters.
title Inferring IGM parameters from the redshifted 21-cm Power Spectrum using Artificial Neural Networks
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2407.03523