Power spectrum extraction for redshifted 21-cm Epoch of Reionization experiments: the LOFAR case
2010 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 405, no 4, 2492-2504 p.Article in journal (Refereed) Published
One of the aims of the Low Frequency Array (LOFAR) Epoch of Reionization (EoR) project is to measure the power spectrum of variations in the intensity of redshifted 21-cm radiation from the EoR. The sensitivity with which this power spectrum can be estimated depends on the level of thermal noise and sample variance, and also on the systematic errors arising from the extraction process, in particular from the subtraction of foreground contamination. We model the extraction process using realistic simulations of the cosmological signal, the foregrounds and noise, and so estimate the sensitivity of the LOFAR EoR experiment to the redshifted 21-cm power spectrum. Detection of emission from the EoR should be possible within 360 h of observation with a single station beam. Integrating for longer, and synthesizing multiple station beams within the primary (tile) beam, then enables us to extract progressively more accurate estimates of the power at a greater range of scales and redshifts. We discuss different observational strategies which compromise between depth of observation, sky coverage and frequency coverage. A plan in which lower frequencies receive a larger fraction of the time appears to be promising. We also study the nature of the bias which foreground fitting errors induce on the inferred power spectrum and discuss how to reduce and correct for this bias. The angular and line-of-sight power spectra have different merits in this respect, and we suggest considering them separately in the analysis of LOFAR data.
Place, publisher, year, edition, pages
2010. Vol. 405, no 4, 2492-2504 p.
cosmology: theory, diffuse radiation, methods: statistical, radio lines: general
IdentifiersURN: urn:nbn:se:su:diva-49703DOI: 10.1111/j.1365-2966.2010.16628.xISI: 000279450900030OAI: oai:DiVA.org:su-49703DiVA: diva2:379304
authorCount :162010-12-172010-12-172011-05-09Bibliographically approved