Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/6891
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dc.contributor.authorSingh, Saurabh-
dc.contributor.authorSubrahmanyan, Ravi-
dc.contributor.authorUdaya Shankar, N.-
dc.contributor.authorSathyanarayana Rao, Mayuri-
dc.contributor.authorGirish, B.S.-
dc.contributor.authorRaghunathan, A.-
dc.contributor.authorSomashekar, R.-
dc.contributor.authorSrivani, K.S.-
dc.date.accessioned2018-05-14T15:03:54Z-
dc.date.available2018-05-14T15:03:54Z-
dc.date.issued2018-04-03-
dc.identifier.citationExperimental Astronomy, 2018, Vol. 45, p269-314en_US
dc.identifier.issn1572-9508-
dc.identifier.issn0922-6435 (Online)-
dc.identifier.urihttp://hdl.handle.net/2289/6891-
dc.descriptionRestricted Access. An open-access version is available at arXiv.org (one of the alternative locations)en_US
dc.description.abstractThe global 21-cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts z∼6−30z∼6−30 , probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious signals can be well calibrated and any calibration residual does not mimic the signal. Shaped Antenna measurement of the background RAdio Spectrum (SARAS) is an ongoing experiment that aims to detect the global 21-cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additive signals leave no residuals with Fourier amplitudes exceeding 2 mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2 mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS 2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.en_US
dc.language.isoenen_US
dc.publisherSpringeren_US
dc.relation.urihttp://cdsads.u-strasbg.fr/abs/2018ExA....45..269Sen_US
dc.relation.urihttps://arxiv.org/abs/1710.01101en_US
dc.relation.urihttp://dx.doi.org/10.1007/s10686-018-9584-3en_US
dc.rights2018 Springeren_US
dc.titleSARAS 2: a spectral radiometer for probing cosmic dawn and the epoch of reionization through detection of the global 21-cm signalen_US
dc.typeArticleen_US
Appears in Collections:Research Papers (A&A)

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