Brute-Force Mapmaking with Compact Interferometers: A MITEoR Northern Sky Map from 128 MHz to 175 MHz

Understand

We present a new method for interferometric imaging that is ideal for the large fields of view and compact arrays common in 21 cm cosmology.

• We first demonstrate the method with simulations for two very different low frequency interferometers, the Murchison Widefield Array (MWA) and the MIT Epoch of Reionization (MITEoR) Experiment.
• We then apply the method to the MITEoR data set collected in July 2013 to obtain the first northern sky map from 128 MHz to 175 MHz at about 2 degree resolution, and find an overall spectral index of -2.73+/-0.11.
• The success of this imaging method bodes well for upcoming compact redundant low-frequency arrays such as HERA.