Development of the Super High Angular Resolution Principle （SHARP） for coded-mask X-ray imaging is presented. We prove that SHARP can be considered as a generalized coded mask imaging method with a coding pattern comprised of diffraction-interference fringes in the mask pattern. The angular resolution of SHARP can be improved by detecting the fringes more precisely than the mask＇s element size, i.e. by using a detector with a pixel size smaller than the mask＇s element size. The proposed mission SHARP-X for solar X-ray observations is also briefly discussed.
We have analyzed International Gamma-Ray Astrophysics Laboratory(INTEGRAL) data corresponding to observations of the high mass X-ray binary(HMXB) V0332+53 during its huge outburst which occurred in 2004-2005,and found that there is a quasi periodic signal with ultra low frequency of roughly 4-5×10-5 Hz in the observation.This feature is revealed through a series of consistent analyses of imagings and fittings of the energy spectrum for each science window(SCW),and shows up in the corresponding light curves.The analysis of the power spectrum also provides a hint of a power peak located around 4×10-5 Hz,after subtracting off the linear trend of the light curve,and shows the consistency with the previous analyses.A similar feature shows up in our analysis of the light curve of Crab in hexagonal dithering mode.Therefore,an instrumental effect on the flux modulation might exist in the INTEGRAL data product of different levels:imaging,spectral fitting and light curve analysis,at least for the observational mode of hexagonal dithering.Such an effect is,to our knowledge,not yet available in the current literature.
CHEN YuPeng,ZHANG Shu,WANG JianMin,LI TiPei & QU JinLu Laboratory for Particle Astrophysics,Institute of High Energy Physics,Beijing 100049,China
We report the discovery of 4 strong gravitational lensing systems by visual inspections of the Sloan Digital Sky Survey images of galaxy clusters in Data Release 6 （SDSS DR6）. Two of the four systems show Einstein rings while the others show tangen- tial giant arcs. These arcs or rings have large angular separations （〉 8″） from the bright central galaxies and show bluer color compared with the red cluster galaxies. In addition, we found 5 probable and 4 possible lenses by galaxy clusters.
Zhong-Lue WenJin-Lin HanXiang-Yang XuYun-Ying JiangZhi-Qing GuoPeng-Fei WangFeng-Shan Liu
