Upper Limits on the 21 cm Epoch of Reionization Power Spectrum from One Night with LOFAR
- Creators
- Patil, A. H.
- Vedantham, H.
Abstract
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 Δ^2_I = (56 ± 13 mK)^2 (1-σ) excess variance and a best 2-σ upper limit of Δ^2_(21) < (79.6 mK)^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.
Additional Information
© 2017 The American Astronomical Society. Received 2016 September 13; revised 2017 February 27; accepted 2017 February 27; published 2017 March 24. LOFAR, the Low-Frequency Array designed and constructed by ASTRON, has facilities in several countries, which are owned by various parties (each with their own funding sources), and are collectively operated by the International LOFAR Telescope (ILT) foundation under a joint scientific policy. S.Z. and A.P. would like to thank the Netherlands Organisation for Scientific Research (NWO) VICI grant for financial support. L.V.E.K., H.V., A.G., S.D., and B.K.G. thank the European Research Council Starting Grant (639.043.308) for support. A.G.d.B., A.R.O., S.B.Y., V.N.P., M.M., H.V., and M.H. acknowledge support from the ERC (grant 339743, LOFARCORE). M.M., V.N.P., and S.B.Y. also acknowledge support from the NWO TOP grant (614.001.005). V.J. would like to thank the Netherlands Foundation for Scientific Research (NWO) for financial support through VENI grant 639.041.336. I.T.I. was supported by the Science and Technology Facilities Council (grant number ST/I000976/1). S.M. would like to acknowledge the financial assistance from the European Research Council under ERC grant number 638743-FIRSTDAWN and from the European Unions Seventh Framework Programme FP7-PEOPLE-2012-CIG grant number 321933-21ALPHA.Attached Files
Published - Patil_2017_ApJ_838_65.pdf
Submitted - 1702.08679.pdf
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Additional details
- Eprint ID
- 75392
- Resolver ID
- CaltechAUTHORS:20170324-123307408
- 639.043.308
- European Research Council (ERC)
- 339743
- European Research Council (ERC)
- 614.001.005
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- 639.041.336
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- ST/I000976/1
- Science and Technology Facilities Council (STFC)
- 638743-FIRSTDAWN
- European Research Council (ERC)
- 321933-21ALPHA
- European Research Council (ERC)
- Created
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2017-03-24Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field