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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2508.04164 |
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| _version_ | 1866909724169994240 |
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| author | Trott, Cathryn M. Nunhokee, C. D. Null, D. Barry, N. Qin, Y. Wayth, R. B. Line, J. L. B. Jordan, C. H. Pindor, B. Cook, J. H. Bowman, J. Chokshi, A. Ducharme, J. Elder, K. Guo, Q. Hazelton, B. J. Hidayat, W. Ito, T. Jacobs, D. Jong, E. Kolopanis, M. Kunicki, T. Lilleskov, E. Morales, M. F. Pober, J. Selvaraj, A. Shi, R. Takahashi, K. Tingay, S. J. Webster, R. L. Yoshiura, S. Zheng, Q. |
| author_facet | Trott, Cathryn M. Nunhokee, C. D. Null, D. Barry, N. Qin, Y. Wayth, R. B. Line, J. L. B. Jordan, C. H. Pindor, B. Cook, J. H. Bowman, J. Chokshi, A. Ducharme, J. Elder, K. Guo, Q. Hazelton, B. J. Hidayat, W. Ito, T. Jacobs, D. Jong, E. Kolopanis, M. Kunicki, T. Lilleskov, E. Morales, M. F. Pober, J. Selvaraj, A. Shi, R. Takahashi, K. Tingay, S. J. Webster, R. L. Yoshiura, S. Zheng, Q. |
| contents | We explore the properties of interferometric data from high-redshift 21~cm measurements using the Murchison Widefield Array. These data contain redshifted 21~cm signal, contamination from continuum foreground sources, and radiometric noise. The 21~cm signal from the Epoch of Reionization is expected to be highly-Gaussian, which motivates the use of the power spectrum as an effective statistical tool for extracting astrophysical information. We find that foreground contamination introduces non-Gaussianity into the distribution of measurements, and then use this information to separate Gaussian from non-Gaussian signal. We present improved upper limits on the 21cm EoR power spectrum from the MWA using a Gaussian component of the data, based on the existing analysis from Nunhokee et al (2025). This is extracted as the best-fitting Gaussian to the measured data. Our best 2 sigma (thermal+sample variance) limit for 268 hours of data improves from (30.2~mK)^2 to (23.0~mK)^2 at z=6.5 for the EW polarisation, and from (39.2~mK)^2 to (21.7~mK)^2 = 470~mK^2 in NS. The best limits at z=6.8 (z=7.0) improve to P < (25.9~mK)^2 (P < (32.0~mK)^2), and k = 0.18h/Mpc (k = 0.21h/Mpc). Results are compared with realistic simulations, which indicate that leakage from foreground contamination is a source of the non-Gaussian behaviour. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_04164 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Improved limits on the 21cm signal at z=6.5-7.0 with the MWA using Gaussian information Trott, Cathryn M. Nunhokee, C. D. Null, D. Barry, N. Qin, Y. Wayth, R. B. Line, J. L. B. Jordan, C. H. Pindor, B. Cook, J. H. Bowman, J. Chokshi, A. Ducharme, J. Elder, K. Guo, Q. Hazelton, B. J. Hidayat, W. Ito, T. Jacobs, D. Jong, E. Kolopanis, M. Kunicki, T. Lilleskov, E. Morales, M. F. Pober, J. Selvaraj, A. Shi, R. Takahashi, K. Tingay, S. J. Webster, R. L. Yoshiura, S. Zheng, Q. Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics We explore the properties of interferometric data from high-redshift 21~cm measurements using the Murchison Widefield Array. These data contain redshifted 21~cm signal, contamination from continuum foreground sources, and radiometric noise. The 21~cm signal from the Epoch of Reionization is expected to be highly-Gaussian, which motivates the use of the power spectrum as an effective statistical tool for extracting astrophysical information. We find that foreground contamination introduces non-Gaussianity into the distribution of measurements, and then use this information to separate Gaussian from non-Gaussian signal. We present improved upper limits on the 21cm EoR power spectrum from the MWA using a Gaussian component of the data, based on the existing analysis from Nunhokee et al (2025). This is extracted as the best-fitting Gaussian to the measured data. Our best 2 sigma (thermal+sample variance) limit for 268 hours of data improves from (30.2~mK)^2 to (23.0~mK)^2 at z=6.5 for the EW polarisation, and from (39.2~mK)^2 to (21.7~mK)^2 = 470~mK^2 in NS. The best limits at z=6.8 (z=7.0) improve to P < (25.9~mK)^2 (P < (32.0~mK)^2), and k = 0.18h/Mpc (k = 0.21h/Mpc). Results are compared with realistic simulations, which indicate that leakage from foreground contamination is a source of the non-Gaussian behaviour. |
| title | Improved limits on the 21cm signal at z=6.5-7.0 with the MWA using Gaussian information |
| topic | Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics |
| url | https://arxiv.org/abs/2508.04164 |