The Ginga satellite
Ginga on the launcher
Ginga's instrumentation
The Large Area Proportional Counter (LAC)
The sudden commencement of accretion of gas from a low-mass star onto a
companion compact object leads to a huge outpouring of relatively soft
X-ray emission (an X-ray nova).This
X-ray light curve from the Ginga satellite shows such an event. The
flux can exceed that of the brightest persistant X-ray sources. The study
of the early phases of these events with the Rossi X-ray Timing Experiment
(RXTE) will probe the cause of the sudden accretion. Optical
identifications should lead to new candidate black holes.
Rapid aperiodic pulsing (quasi-
periodic oscillations; QPO's) in low-mass X-ray binaries is probably
due to interactions between the circulating matter in the accretion disk
and the magnetosphere of the neutron star. These pulsations are directly
seen with the Ginga satellite during a burst from the "Rapid Burster"
source. The mechanism that gives rise to QPO pulsations is not yet known.
They may be symptomatic of a heretofore undetected pulsar spinning almost
1000 times a second.
Spectral features found at relatively high X-ray energies are believed to
be due to electrons spiraling in the very high magnetic field of neutron
stars. The absorption feature in the
spectra of the X-ray pulsar 1538-52 observed by Ginga is seen to vary
with the (numbered) phase of the pulsing. This cyclotron radiation
is a direct diagnostic of the hot plasmas and strong magnetic fields in
the polar regions of the neutron star.
The cross correlation of the X-ray and
optical fluxes of BY Cam show the rapid flickering in both bands to be
highly correlated on ~1 minute time scales. BY Cam (=H0538+608) is a
magnetic white-dwarf cataclysmic-variable system (AM Her type). The
radiation may originate in a shock front just above the white-dwarf
surface. This detection required the large apertures of the Ginga
satellite and simultaneous optical and X-ray observations (Silber
et al 1992, ApJ, 389, 704).
