HI 21cm Cosmology and the Bi-spectrum: Closure Diagnostics in Massively Redundant Interferometric Arrays

Understand

New massively redundant low frequency arrays allow for a novel investigation of closure relations in interferometry.

• We employ commissioning data from the Hydrogen Epoch of Reionization Array to investigate closure quantities in this densely packed grid array of 14m antennas operating at 100 MHz to 200 MHz.
• We investigate techniques that utilize closure phase spectra for redundant triads to estimate departures from redundancy for redundant baseline visibilities.
• We find a median absolute deviation from redundancy in closure phase across the observed frequency range of about 4.5deg.