MITEoR: a scalable interferometer for precision 21 cm cosmology

Abstract

We report on the MIT Epoch of Reionization (MITEoR) experiment, a pathfinder\nlow-frequency radio interferometer whose goal is to test technologies that\nimprove the calibration precision and reduce the cost of the high-sensitivity\n3D mapping required for 21 cm cosmology. MITEoR accomplishes this by using\nmassive baseline redundancy, which enables both automated precision calibration\nand correlator cost reduction. We demonstrate and quantify the power and\nrobustness of redundancy for scalability and precision. We find that the\ncalibration parameters precisely describe the effect of the instrument upon our\nmeasurements, allowing us to form a model that is consistent with $\\chi^2$ per\ndegree of freedom < 1.2 for as much as 80% of the observations. We use these\nresults to develop an optimal estimator of calibration parameters using Wiener\nfiltering, and explore the question of how often and how finely in frequency\nvisibilities must be reliably measured to solve for calibration coefficients.\nThe success of MITEoR with its 64 dual-polarization elements bodes well for the\nmore ambitious Hydrogen Epoch of Reionization Array (HERA) project and other\nnext-generation instruments, which would incorporate many identical or similar\ntechnologies.\n