Multi-redshift limits on the 21cm power spectrum from PAPER

Abstract

The epoch of reionization power spectrum is expected to evolve strongly with redshift, and it is this variation with cosmic history that will allow us to begin to place constraints on the physics of reionization. The primary obstacle to the measurement of the EoR power spectrum is bright foreground emission. We present an analysis of observations from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) telescope which place new limits on the HI power spectrum over the redshift range of $7.5<z<10.5$, extending previously published single redshift results to cover the full range accessible to the instrument. To suppress foregrounds, we use filtering techniques that take advantage of the large instrumental bandwidth to isolate and suppress foreground leakage into the interesting regions of $k$-space. Our 500 hour integration is the longest such yet recorded and demonstrates this method to a dynamic range of $10^4$. Power spectra at different points across the redshift range reveal the variable efficacy of the foreground isolation. Noise limited measurements of ${\Delta }^2$ at $k=$0.2hMpc${}^{-1}$ and z$=7.55$ reach as low as (48mK)${}^2$ ($1\sigma$). We demonstrate that the size of the error bars in our power spectrum measurement as generated by a bootstrap method is consistent with the fluctuations due to thermal noise. Relative to this thermal noise, most spectra exhibit an excess of power at a few sigma. The likely sources of this excess include residual foreground leakage, particularly at the highest redshift, and unflagged RFI. We conclude by discussing data reduction improvements that promise to remove much of this excess.

9 pages, submitted to apj, fixed author list and abstract typo

References in corpus (6)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array
• Fast Holographic Deconvolution: a new technique for precision radio interferometry
• MITEoR: A Scalable Interferometer for Precision 21 cm Cosmology
• A Fast Method for Power Spectrum and Foreground Analysis for 21 cm Cosmology
• New 145-MHz Source Measurements by PAPER in the Southern Sky

Cited by in corpus (16)

• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• First Season MWA EoR Power Spectrum Results at Redshift 7
• Results from EDGES High-Band: I. Constraints on Phenomenological Models for the Global $21$ cm Signal
• Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array
• Mitigating Internal Instrument Coupling for 21 cm Cosmology I: Temporal and Spectral Modeling in Simulations
• Bubble size statistics during reionization from 21-cm tomography
• Towards simulating and quantifying the light-cone EoR 21-cm signal
• Spherical Harmonic Analyses of Intensity Mapping Power Spectra
• Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum
• Studying 21cm power spectrum with one-point statistics
• Constraining Polarized Foregrounds for EOR Experiments II: Polarization Leakage Simulations in the Avoidance Scheme
• Warm Dark Matter and Cosmic Reionization
• The Engineering Development Array: A low frequency radio telescope utilising SKA precursor technology
• Upper Limits on the 21 cm Power Spectrum at z = 5.9 from Quasar Absorption Line Spectroscopy
• Line of sight anisotropies in the Cosmic Dawn and EoR 21-cm power spectrum
• Foreground and sensitivity analysis for broad band (2D) 21cm--Ly-alpha and 21cm--H-alpha correlation experiments probing the Epoch of Reionization