Upper Limits on the 21 cm Epoch of Reionization Power Spectrum from One Night with LOFAR
By A. H. Patil, S. Yatawatta, Leon V. E. Koopmans, A. Bruyn, M. Brentjens, S. Zaroubi, K. Asad, M. Hatef, V. Jelic, M. Mevius and 18 more. 2017
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We present the first limits on the Epoch of Reionization 21 cm H i power spectra, in the redshift range z = 7.9–10.6, using the Low-Frequency Array (LOFAR) High-Band Antenna (HBA). In total, 13.0 hr of data were used from observations centered on the North Celestial Pole. After subtraction of the sky model and the noise bias, we detect a non-zero (1-σ) excess variance and a best 2-σ upper limit of at k = 0.053 h cMpc−1 in the range z = 9.6–10.6. The excess variance decreases when optimizing the smoothness of the direction- and frequency-dependent gain calibration, and with increasing the completeness of the sky model. It is likely caused by (i) residual side-lobe noise on calibration baselines, (ii) leverage due to nonlinear effects, (iii) noise and ionosphere-induced gain errors, or a combination thereof. Further analyses of the excess variance will be discussed in forthcoming publications.
Subfields: Aerospace Engineering, Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/1254d77026b81d5257a8510406cb2d6eb1a90f95
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In Astronomy and Astrophysics
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Citations in the corpus
- Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, methodology): “To demonstrate the improvement in the calibration, we process one night of observation (L246309) with the DDcalibration regularization parameters used in Patil et al. (2017).”
- Fundamental physics with the Square Kilometre Array (2018, background): “These are exciting times for cosmic dawn and reionisation, as the pathfinder experiments LOFAR (Patil et al., 2017), MWA (Dillon et al., 2015), PAPER (Ali et al., 2015), and HERA (DeBoer et al., 2017) have begun to collect data and set upper limits on the 21-cm power spectrum, while EDGES has report”