EIGSEP's Novel Beam Mapping Implementation
Dominic Vazquez
Department of Physics & Astronomy
Faculty Supervisor: Charli Sakari
The Cosmic Dark Ages and Cosmic Dawn are eras of the Universe inaccessible to most methods of observation with the exception of the 21-cm hydrogen line. Although the sky averaged 21-cm hydrogen line (global signal) seems like a promising cosmological probe, telling us when the first stars formed, the thermal history of the Intergalactic Medium, and putting constraints on the era of Reionization, measurements are difficult due to the bright galactic foregrounds and coupled systematics. The Electromagnetically Isolated Global Signal Estimation Platform (EIGSEP) attempts to overcome these issues by suspending and rotating an antenna between a canyon about 100 meters in the air. EIGSEP's suspension and rotations directly address the common experimental issue of the uneven weighting of the sky and ground from their antenna's beam pattern. The beam pattern, a description of how sensitive the antenna is in a given direction and frequency, can easily inject complex non-cosmological structure into the global signal measurements. EIGSEP will measure its beam pattern as both a function of angle and frequency by using an external transmitter in-situ with observations. This beam mapping can then be used to account for uneven weighting in the retrieval of the global signal.