Ginga


Ginga

(jing -gă) A Japanese X-ray astronomy satellite that was launched into a 600 km, 31° inclination orbit in Feb. 1987, and operated near perfectly until reentry in Nov. 1991. It continued the X-ray studies begun with the satellites Hakucho and Tenma. The major payload was a 5000 cm2 array of proportional counter detectors capable of spectral and variability studies. The mission yielded the most detailed timing and broad-band spectral data available over the 2–20 keV band on a wide range of cosmic sources. Initially operated as a Japanese/UK collaboration, Ginga observations were subsequently opened up to world-wide use. Major advances included: the discovery of spectral features in active galactic nuclei, arising from reflection in previously unseen cold dense matter; measurement of temperature and chemical abundance differences in clusters of galaxies, indicative of evolution and merging; resolution of Doppler shifted iron K-line emission from the galactic binary source SS433; the discovery of many new cataclysmic variables and several galactic black hole candidate systems. Complete archives (X-ray databases) of the Ginga data have now been established at ISAS and Leicester University, UK. See also Asca.