Speaker
Description
The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a radio interferometer currently being deployed in the Karoo Desert, South Africa. It aims to constrain the dark energy equation-of-state parameter using accurate measurements of baryon acoustic oscillations (BAO) via 21cm intensity mapping. It will be equipped with 1024 dishes, each 6m in diameter, arranged in a regular, compact grid, operating in the 400-800 MHz frequency range corresponding to redshifts 0.75 < z < 2.5. Like all radio arrays, HIRAX also suffers from instrumental systematics, among which the spatial and spectral shapes of the primary beam are worrisome, and understanding and characterizing them is critical for precision cosmology. This talk will introduce the effects of the primary beam and discuss the recent work on measuring the HIRAX prototype beam using solar transit observations. These data provide a direct probe of the instrumental response across frequency and offer a complementary perspective to beam models derived from EM simulations. This talk will include discussions on observations, analysis, key features observed in the prototype data, and how this informs ongoing beam modeling efforts for HIRAX.