摘要：NuSTAR (Nuclear Spectroscopic Telescope Array) and IXO
(International X-ray Observatory) missions are two of NASA X-ray
missions for the coming decade. NuSTAR is a small explorer class mission
that will for the first time use multilayer-coated X-ray mirror
assemblies to focus X-rays up to 80 keV. Among other objectives, its
major science area will be to conduct surveys to identify hard X-ray
sources and to resolve the diffuse X-ray background.  IXO, a
collaborative mission of NASA, ESA, and JAXA, will be an observatory
class mission. It will have a 3m in diameter X-ray mirror assembly with
an unprecedented photon collection area a suite of focal plane
detectors: a grating system, a large format CCD imaging system, a
calorimeter, a polarimeter, and a high resolution and fast timing
detector. It will significantly advance the spectroscopic and timing
studies of black holes, neutron stars, AGN, IGM, and nearly every other
aspect of the X-ray universe. In this talk I will describe and discuss
the instruments and scientific objectives of these two missions.

报告人简介：William Zhang obtained his Bachelor degree from Peking
University, PhD degree from University of Pennsylvania, and did his
postdocs research at Los Alamos National Lab. He is an internationally
recognized expert and leader in X-ray astronomy. As well as achieved
distinguished scientific research records in high energy gamma-ray and
X-ray astronomy, he has played a major role in the RXTE mission.
Currently he is leading NASA’s X-ray optics program, is a key person in
the IXO mission, and the project scientist of the NuSTAR mission.