Cray XC30 “Aterui” is the 4th generation of dedicated numerical simulation supercomputers employed by the NAOJ. Installed at the Mizusawa VLBI Observatory, collaborative use started in April 2013. Using an extremely large number of cores (24,192 cores), the entire system can achieve 502 Tflops* (a unit for measuring high-speed scientific calculations). In that environment, Aterui creates a universe and resolves experimental astronomical phenomena. It can be called a telescope for theoretical astronomy.

The Universe Aterui Sees

What Aterui calculates is every possible phenomenon in the Universe. It handles a wide range of astronomical phenomena, from the extremely large scale of the formation of the overall structure of the Universe; to the small scale of how Earth-like planets are formed. It can also shed light on a variety of time scales from the 13.8 billion years between the start of the Universe and the present; down to the explosions of stars, which take less than a second.

The Origin of Aterui

Aterui was the leader of the Ezo (Ainu) people living around modern day Mizusawa from the Nara Era into the early Heian Era. We know he was a hero who fought bravely against a large military expedition sent by the emperor. We nicknamed this supercomputer Aterui because we want it to boldly defy the mysteries of the Universe here on Mizusawa soil. An electronic circuit stylization of the tensho kanji (traditional block style lettering) for “Aterui” (阿弖流為) is written on the left side of the housing.

VLBI = Very Long Baseline Interferometry

(*Tflops = Tera-FLOPS = 1 Trillion Floating-point Operations Per Second)

(Translator's Note: In addition to the standard Gregorian Calendar, Japan continues to use a reign era calendar. The different eras are defined by changes in the Japanese government, and accompanied by changes in Japanese society.)