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Upper limits on the 21 cm Epoch of Reionization power spectrum from one night with LOFAR

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posted on 2023-06-09, 06:51 authored by A H Patil, Ilian IlievIlian Iliev, et al
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 I 56 13 mK D2 = ? 2 ( ) (1-s) excess variance and a best 2-s upper limit of 21 79.6 mK D2 < 2 ( ) 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.

History

Publication status

  • Published

File Version

  • Published version

Journal

Astrophysical Journal

ISSN

0004-637X

Publisher

Institute of Physics

Issue

1

Volume

838

Article number

a65

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Astronomy Centre Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2017-06-22

First Open Access (FOA) Date

2017-06-22

First Compliant Deposit (FCD) Date

2017-06-21

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