Confirmation of wide-field signatures in redshifted 21 cm power spectra
MetadataShow full item record
We confirm our recent prediction of the "pitchfork" foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H i signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio >10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ~40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum.
Copyright © 2015 The American Astronomical Society. Reproduced with permission.
Showing items related by title, author, creator and subject.
Thyagarajan, N.; Jacobs, D.; Bowman, J.; Barry, N.; Beardsley, A.; Bernardi, G.; Briggs, F.; Cappallo, R.; Carroll, P.; Corey, B.; Oliveira-Costa, A.; Dillon, J.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Goeke, R.; Greenhill, L.; Hazelton, B.; Hewitt, J.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D.; Kasper, J.; Kim, H.; Kittiwisit, P.; Kratzenberg, E.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C.; Lynch, Mervyn; McKinley, B.; McWhirter, S.; Mitchell, D.; Morales, M.; Morgan, E.; Neben, A.; Oberoi, D.; Offringa, A.; Ord, Stephen; Paul, S.; Pindor, B.; Pober, J.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A.; Roshi, A.; Shankar, N.; Sethi, S.; Srivani, K.; Subrahmanyan, R.; Sullivan, I.; Tegmark, M.; Tingay, Steven; Trott, C.; Waterson, M.; Wayth, Randall; Webster, R.; Whitney, A.; Williams, A.; Williams, C.; Wu, C.; Wyithe, J. (2015)Detection of 21 cm emission of H I from the epoch of reionization, at redshifts z > 6, is limited primarily by foreground emission. We investigate the signatures of wide-field measurements and an all-sky foreground model ...
Comparison of Observing Modes for Statistical Estimation of the 21 cm Signal from the Epoch of ReionisationTrott, Cathryn (2014)Noise considerations for experiments that aim to statistically estimate the 21 cm signal from high redshift neutral hydrogen during the Epoch of Reionisation (EoR) using interferometric data are typically computed assuming ...
Hashemnia, N.; Abu-Siada, Ahmed; Masoum, Mohammad Sherkat; Islam, Syed (2012)Frequency response analysis (FRA) is gaining global popularity in detecting power transformer winding and core deformations due to the development of FRA test equipment. However, because FRA relies on graphical analysis, ...