In this paper, we apply the direct demodulation technique to analyse
simulated data of a rotating modulation collimator telescope for the
first time. The direct demodulation method
has already been applied successfully to image analysis for various kinds of
data in high energy-astronomy, e.g. for data of -ray imaging telescope
COS-B (Li & Wu 1990),
for scan observation data of slat collimator telescopes: the scan imaging
for CygX-1 by the balloon-borne hard X-ray collimated telescope
HAPI-4 (Lu et al. 1995) and for EXOSAT-ME data of the galactic
plane survey (Lu et al. 1996), for data from the Compton
scatter telescope COMPTEL/CGRO (Zhang et al. 1996).
Simulation results show that the direct demodulation technique can
significantly improve imaging quality of the coded mask
aperture telescope (Li 1995). As seen in this paper, the application of
this method to telescopes based on a rotating modulation collimator is also
feasible. Images from RMC with the direct demodulation technique have much
higher angular resolution than those with cross-correlation analysis.
The direct demodulation images have almost no sidelobes and can represent
both discrete and extended structures.
After considering the improved performance with the direct demodulation
method, the RMC technique might be more competitive for future imaging
instrumentation in high-energy astronomy.
Acknowledgements
The authors thank Dr. F.J. Lu and Y.X. Feng for helpful discussions. This work was supported by the National Natural Science Foundation of China.