Informazioni sull’evento


Coffee talks

Thursday 21/12/2023 @ 15:30, Sala riunioni quarto piano e on-line (

Aishwarya Selvaraj (Curtin University, Australia), "Improved foreground mitigation with the Central Redundant Array Mega-tile (CRAM)"

Improved foreground mitigation with the Central Redundant Array Mega-tile (CRAM) Exploration of the 21cm signal from the Epoch of Reionisation (EoR) can unravel the mysteries of the early Universe when the first stars and galaxies were born. However, the 21cm signal is exceptionally weak, and thus the detection amidst the bright foregrounds is extremely challenging. The Murchison Widefield Array (MWA) is an interferometry-based experiment aiming 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 sidelobes near the horizon to contaminate the measurements. Thus, the Central Redundant Array Mega-tile (CRAM) is installed at the centre of one of the MWA's hexagonal subarrays and comprises 64 dipoles in an 8x8 configuration (compared with the MWA's 4x4). The CRAM tile will measure the sky with a smaller primary beam when compared to the MWA tile. The coherent information from the simultaneous measurements from the CRAM-MWA tiles will be used to statistically understand the differences compared to the MWA-MWA tiles. The key implication of this work is to reduce the impact of bright radio galaxies by using CRAM of reduced FoV and increase the parameter space of the EoR window. In this talk, I will present the results from the ongoing work which compares the characteristics of the CRAM tile with the existing MWA configuration. Further, I will present the power spectrum estimates from simulations obtained using MWA-MWA baselines and CRAM-MWA baselines. The results demonstrate how the EoR parameter space can be improved by employing an instrument with a smaller FoV, such as the CRAM.