Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-28T05:35:29.726Z Has data issue: false hasContentIssue false
  • English
  • Français

Wide-field LOFAR-LBA power-spectra analyses: Impact of calibration, polarization leakage and ionosphere

Published online by Cambridge University Press:  08 May 2018

Bharat K. Gehlot  and
Léon V. E. Koopmans
Bharat K. Gehlot*
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700AV Groningen, the Netherlands
Léon V. E. Koopmans
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700AV Groningen, the Netherlands
*
*email: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Contamination due to foregrounds, calibration errors and ionospheric effects pose major challenges in detection of the cosmic 21 cm signal in various Epoch of Reionization (EoR) experiments. We present the results of a study of a field centered on 3C196 using LOFAR Low Band observations, where we quantify various wide field and calibration effects such as gain errors, polarized foregrounds, and ionospheric effects. We observe a ‘pitchfork’ structure in the power spectrum of the polarized intensity in delay-baseline space, which leaks into the modes beyond the instrumental horizon. We show that this structure arises due to strong instrumental polarization leakage (~30%) towards Cas A which is far away from primary field of view. We measure a small ionospheric diffractive scale towards CasA resembling pure Kolmogorov turbulence. Our work provides insights in understanding the nature of aforementioned effects and mitigating them in future Cosmic Dawn observations.

Keywords

cosmology: observationstechniques: interferometricpolarizationtechniques: polarimetricatmospheric effectsmethods: statistical
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 12 , Symposium S333: Peering towards Cosmic Dawn , October 2017 , pp. 106 - 109
Copyright
Copyright © International Astronomical Union 2018 

References

Barry, N., Hazelton, B., Sullivan, I., Morales, M. F. & Pober, J. C., 2016, MNRAS, 461, 3135Google Scholar
Bowman, J. D., et al., 2013, Publ. Astron. Soc. Australia, 30, e031CrossRefGoogle Scholar
DeBoer, D. R., 2015, in American Astronomical Society Meeting Abstracts, p. 328.03Google Scholar
Ewall-Wice, A., Dillon, J. S., Liu, A. & Hewitt, J., 2017, MNRAS, 470, 1849CrossRefGoogle Scholar
Furlanetto, S. R., Oh, S. P. & Briggs, F. H., 2006, Phys. Rep., 433, 181Google Scholar
Gehlot, B. K., Koopmans, L., et al., 2017, arXiv 1709.07727Google Scholar
Koopmans, L., et al., 2015, Advancing Astrophysics with the Square Kilometre Array (AASKA14), p. 1Google Scholar
Madau, P., Meiksin, A., & Rees, M. J., 1997, ApJ, 475, 429CrossRefGoogle Scholar
Mellema, G., et al., 2013, Experimental Astronomy, 36, 235Google Scholar
Paciga, G., et al., 2011, MNRAS, 413, 1174Google Scholar
Parsons, A. R., et al., 2010, AJ, 139, 1468CrossRefGoogle Scholar
Patil, A. H., et al., 2016, MNRAS, 463, 4317Google Scholar
Patil, A. H., et al., 2017, ApJ, 838, 65Google Scholar
Pritchard, J. R. & Loeb, A., 2012, Reports on Progress in Physics, 75, 086901Google Scholar
Shaver, P. A., Windhorst, R. A., Madau, P., & de Bruyn, A. G., 1999, A&A, 345, 380Google Scholar
Tingay, S. J., et al., 2013, Publ. Astron. Soc. Australia, 30, e007Google Scholar
Vedantham, H. K. & Koopmans, L. V. E., 2015, MNRAS, 453, 925Google Scholar
Vedantham, H. K., Koopmans, L. V. E., 2016, MNRAS, 458, 3099Google Scholar
Zarka, P., Girard, J. N., Tagger, M. & Denis, L., 2012, in Boissier, S., de Laverny, P., Nardetto, N., Samadi, R., Valls-Gabaud, D., Wozniak, H., eds, SF2A-2012: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics., pp 687–694Google Scholar
Zaroubi, S., 2013, in Wiklind, T., Mobasher, B., Bromm, V., eds, Astrophysics and Space Science Library, Vol. 396, The First Galaxies. p. 45 arXiv 1206.0267Google Scholar
Zheng, Q., Wu, X.-P., Johnston-Hollitt, M., Gu, J.-h., & Xu, H., 2016, ApJ, 832, 190CrossRefGoogle Scholar
van Haarlem, M. P., et al., 2013, A&A, 556, A2Google Scholar