Speaker
Description
Exploration of the 21cm signal from the Cosmic Dawn and the Epoch of Reionisation (EoR) can unravel the mysteries of the early Universe when the first stars and galaxies were born and reionised the intergalactic medium. However, the 21cm signal is exceptionally weak; thus, detecting amidst the bright foregrounds is extremely challenging. The Murchison Widefield Array (MWA) aims to measure the brightness temperature fluctuations of neutral hydrogen from the early Universe. The MWA telescope observes the radio sky with a large Field of View (FoV) that causes the bright galaxies in the side lobes near the horizon to contaminate the measurements.
In response to the challenges faced, a new zenith-pointing instrument, the Central Redundant Array Mega-tile (CRAM), is installed and integrated into the Phase II configuration of MWA. The CRAM (consists of 8 x 8 dipoles) is twice the size of a regular MWA tile in each dimension (which consists of 4 x 4 dipoles), and therefore, it has half the FoV at each frequency under consideration. The primary objective of this new instrument is to mitigate the impact of bright radio sources near the field centre in accordance with the reduced primary beam shape and reduce the contamination of foreground sources near the horizon with the reduced sidelobe response of the larger array configuration.
In this talk, I will briefly present the details of the instrument, the data acquisition process, and the gain and receiver temperature estimation analysis, leading to the work for my first paper. Further, I will present how the new instrument will benefit EoR science, using the results obtained through power spectrum simulations. I will demonstrate how the new instrument, with a reduced FoV, can reduce the impact of the foregrounds. Finally, I will conclude with the ongoing work, where I analyse real interferometry data from the hybrid array.
| Timeslot preferences | 20 min |
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