Presentation #314.07 in the session X-ray and Radio Facilities and Instruments.
Observations of the 21cm hydrogen line in the early universe (redshifts 25 to 5) are expected to shed light on the origins of stars, inflation, and dark matter. First generation interferometers have placed ever-lower limits on the fluctuation power spectrum while measurements of global absorption trough at redshift 18. The Hydrogen Epoch of Reionization Array (HERA) is a second generation instrument which aims for a high significance power spectrum measurement between redshifts 5.5 and 12 and experimental observations redshift 18. In 2017 HERA was operated with 20% of its collecting area. This data has been used to develop pipelines and a validation apparatus which has produced new limits on the 21cm power spectrum which offer more constraints on models of early galaxies.