By Ron Cowen
To study some of the hottest regions in the universe, the Japanese Aerospace Exploration Agency has launched the coldest instrument ever flown. Chilled to six-hundredths of a degree above absolute zero, the X-ray Spectrometer-2 is one of six devices carried by a Japanese-NASA satellite now gearing up to study high-energy emissions from such sources as the hot gas expelled by supernovas, the energetic material spiraling into black holes, and the warm gas among stars and between galaxies.
Originally known as Astro-E2, the satellite is identical to a mission that burned up 5 years ago when a launch rocket malfunctioned (SN: 3/25/00, p. 206: Available to subscribers at X-ray telescope vanishes). After the new satellite’s successful launch on July 10, the Japanese agency renamed the satellite Suzaku, the Japanese word for a bird symbolizing renewal in Chinese mythology.
Suzaku records higher-energy X rays than two other missions already in orbit, NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton telescope. A cooler on Suzaku keeps the detector at temperatures low enough to sense the tiny amount of heat imparted by an individual X-ray photon—just a few thousandths of a degree Kelvin.
Thus, the spectrometer is 10 times as accurate as any similar instrument.
