HERA construction is on-going with a goal of the full 350 elements in 2019. Currently efforts are focused on deploying the new systems, which replace everything except the antenna elements themselves. The new feeds operate from about 50-250 MHz and the first units have been deployed and are currently under test (see Figure). The new front-ends send analog RF over optical fiber to the new digitiser/channelizer boards (known as SNAPs) in the field-deployed RF-tight node enclosures. The new front-ends also allow calibration loads to be switched in and may be phase-switched. The new fiber backbone from the HERA site to the Karoo Array Processor Building (KAPB) has been installed which allows the X-engine of the correlator to be located within that infrastructure.
With the inclusion of so much (all!) new signal path hardware, HERA will spend the initial few months of the upcoming observing season in commissioning mode, with science observations starting in October with about 50 new systems. The number of antennas built and used will increase over the season to about 200. Observation features will also be ramped up over this upcoming season, including higher frequency resolution and baseline-dependent averaging. Future features will further increase the frequency resolution and shorten archived integration times.
HERA is a partnership to conduct an experiment to detect and characterize the Epoch of Reionization. Partner institutions in the collaboration are Arizona State University, Brown University, University of California Berkeley, University of California Los Angeles, University of Cambridge, Massachusetts Institute of Technology, National Radio Astronomy Observatory, University of Pennsylvania, Scuola Normale Superiore de Pisa, SKA-South Africa and the University of Washington. Additional collaborators are Cal Poly Pomona, Imperial College, Harvard-Smithsonian Center for Astrophysics, University of KwaZulu Natal, Rhodes University and University of Western Cape. HERA is an SKA precursor instrument. HERA is funded by the US National Science Foundation, the Gordon and Betty Moore Foundation with additional support from the partner institutions.
Report provided by David de boer, University of California Berkeley, HERA Project Manager