Optimal identification of HII regions during reionization in 21-cm observations
arXiv:1801.06550 · doi:10.1093/mnras/sty1786
Abstract
The ability of the future low frequency component of the Square Kilometre Array radio telescope (SKA-Low) to produce tomographic images of the redshifted 21-cm signal will enable direct studies of the evolution of the sizes and shapes of ionized regions during the Epoch of Reionization. However, a reliable identification of ionized regions in noisy interferometric data is not trivial. Here, we introduce an image processing method known as superpixels for this purpose. We compare this method with two other previously proposed ones, one relying on a chosen threshold and the other employing automatic threshold determination using the K-Means algorithm. We use a correlation test and compare power spectra and bubble size distributions to show that the superpixels method provides a better identification of ionized regions, especially in the case of noisy data. We also describe some possible additional applications of the superpixel method, namely the derivation of the ionization history and constraints on the source properties in specific regions.
17 pages, 14 figures, accepted in MNRAS
References in corpus (15)
- scikit-image: Image processing in Python
- Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
- Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
- Efficient Simulations of Early Structure Formation and Reionization
- 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
- Cosmological Radiative Transfer Codes Comparison Project I: The Static Density Field Tests
- Simulating Cosmic Reionization at Large Scales II: the 21-cm Emission Features and Statistical Signals
- Power spectrum extraction for redshifted 21-cm epoch of reionization experiments: the LOFAR case
- Multi-redshift limits on the 21cm power spectrum from PAPER
- Bubble size statistics during reionization from 21-cm tomography
- Imaging the redshifted 21-cm pattern around the first sources during the cosmic dawn using the SKA
- Detection and extraction of signals from the epoch of reionization using higher order one-point statistics
- Detecting ionized bubbles in redshifted 21 cm maps
- Using Artificial Neural Networks to Constrain the Halo Baryon Fraction during Reionization
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