Exploring the cosmic 21-cm signal from the Epoch of Reionisation using the Wavelet Scattering Transform
arXiv:2204.02544 · doi:10.1093/mnras/stac977
Abstract
Detecting the cosmic 21-cm signal during the Epoch of Reionisation and Cosmic Dawn will reveal insights into the properties of the first galaxies and advance cosmological parameter estimation. Until recently, the primary focus for astrophysical parameter inference from the 21-cm signal centred on the power spectrum (PS). However, the cosmic 21-cm signal is highly non-Gaussian rendering the PS sub-optimal for characterising the cosmic signal. In this work, we introduce a new technique to analyse the non-Gaussian information in images of the 21-cm signal called the Wavelet Scattering Transform (WST). This approach closely mirrors that of convolutional neural networks with the added advantage of not requiring tuning or training of a neural network. Instead, it compresses the 2D spatial information into a set of coefficients making it easier to interpret while also providing a robust statistical description of the non-Gaussian information contained in the cosmic 21-cm signal. First, we explore the application of the WST to mock 21-cm images to gain valuable physical insights by comparing to the known behaviour from the 21-cm PS. Then we quantitatively explore the WST applied to the 21-cm signal by extracting astrophysical parameter constraints using Fisher Matrices from a realistic 1000 hr mock observation with the Square Kilometre Array. We find that: (i) the WST applied only to 2D images can outperform the 3D spherically averaged 21-cm PS, (ii) the excision of foreground contaminated modes can degrade the constraining power by a factor of ~1.5-2 with the WST and (iii) higher cadences between the 21-cm images can further improve the constraining power.
25 pages, 16 figures and 2 tables. Accepted for publication in MNRAS
References in corpus (19)
- Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
- Massloss of galaxies due to a UV-background
- Efficient Simulations of Early Structure Formation and Reionization
- The Epoch of Reionization Window: I. Mathematical Formalism
- 21 cm fluctuations from inhomogeneous X-ray heating before reionization
- 21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal
- The Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
- A Simple Technique for Predicting High-Redshift Galaxy Evolution
- Essential physics of early galaxy formation
- 21cmFAST v3: A Python-integrated C code forgenerating 3D realizations of the cosmic 21cm signal
- UV Radiative Feedback During the Advanced Stages of Reionization
- Bubble size statistics during reionization from 21-cm tomography
- Sensitivity for 21cm Bispectrum from Epoch of Reionization
- Studying 21cm power spectrum with one-point statistics
- Constraining the reionization history using deep learning from 21cm tomography with the Square Kilometre Array
- Redshifted 21-cm bispectrum II: Impact of the spin temperature fluctuations and redshift space distortions on the signal from the Cosmic Dawn
- Inferring the properties of the sources of reionization using the morphological spectra of the ionized regions
- Deep-Learning Study of the 21cm Differential Brightness Temperature During the Epoch of Reionization
- Predictions for the 21cm-galaxy cross-power spectrum observable with SKA and future galaxy surveys