Title:	Detecting global signal from cosmic dawn and epoch of reionization with SKA
Authors:	Rao, Mayuri Sathyanarayana Shankar, N. Udaya Subrahmanyan, Ravi Singh, Saurabh
Issue Date:	28-Mar-2023
Publisher:	Indian Academy of Sciences
Citation:	Journal of Astrophysics and Astronomy, 2023, Vol. 44, Article No. 24
Abstract:	A key science project for SKA-Low is the interferometer imaging of spatio-temporal fluctuations in the hydrogen ionization fraction and spin temperature as a diagnostic of cosmic dawn (CD) and epoch of reionization (EoR) in the redshift range 6≲z≲28. However, detection of the global CD/EoR signal, which provides the differential HI 21-cm brightness temperature with respect to the background radiation temperature, is outside the current purview of SKA-Low observing in interferometer mode. This global CD/EoR signal can provide the critical zero-spacing measurement vital for establishing the base level of fluctuations measured by SKA-Low interferometers. We present here, a concept to detect the global CD/EoR signal as a supplement to the CD/EoR key science of SKA-Low. This would be enabled by adding a compact array of outrigger antennas interspersed between the core stations of SKA-Low. The autocorrelations of the outrigger antennas would form the measurement set for the global CD/EoR. The visibilities measured between outriggers and SKA stations would be ‘blind’ to the global CD/EoR signal and would provide a Global Sky Model and calibration of the bandpass and mode-coupling in the primary beam of the outriggers. The global signal measurement capability will strengthen the SKA-Low CD/EoR program.
Description:	Open Access from Indian Academy of Sciences
URI:	http://hdl.handle.net/2289/8072
ISSN:	0250-6335 0973-7758 (Online)
Alternative Location:	https://doi.org/10.1007/s12036-023-09911-5
Copyright:	2023 Indian Academy of Sciences, Bengaluru
Appears in Collections:	Research Papers (A&A)

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