Panel homes in on sites for γ-ray detector

摘要

When very-high-energy γ-rays slam into Earths atmosphere, they trigger particle showers that emit a faint blue light. With this light, astronomers want to trace the rare γ-rays - only a few strike each square metre of the atmosphere each month - back to their sources, violent objects such as supermassive black holes. But first researchers must find a home for the planned €200-million (US$277-million) Cher-enkov Telescope Array (CTA) - or rather, two homes. The telescope will be made up of a 19-dish array in the Northern Hemisphere and a 99-dish array in the south.