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. Both the MITEoR interferometric data and the 150 MHz sky map are publicly available at http://space.mit.edu/home/tegmark/omniscope.html.
@article{arxiv.1605.03980,
title = {Brute-Force Mapmaking with Compact Interferometers: A MITEoR Northern Sky Map from 128 MHz to 175 MHz},
author = {H. Zheng and M. Tegmark and J. Dillon and A. Liu and A. R. Neben and S. Tribiano and R. Bradley and V. Buza and A. Ewall-Wice and H. Gharibyan and J. Hickish and E. Kunz and J. Losh and A. Lutomirski and E. Morgan and S. Morrison and S. Narayanan and A. Perko and D. Rosner and N. Sanchez and K. Schutz and M. Valdez and J. Villasenor and H. Yang and K. Zarb-Adami and I. Zelko and K. Zheng},
journal= {arXiv preprint arXiv:1605.03980},
year = {2016}
}
Comments
15 pages, 7 figures; updated to match MNRAS accepted version