Lead Scientist of HXMT Zhang Shuangnan: "Huiyan" Eyes Three Major Breakthroughs

Huiyan, China's first Hard X-ray Modulation Telescope satellite, was sent into sky atop a Long March 4B rocket, representing the first China-owned large astronomical telescope in the vast space.

In 1970, Uhuru, the first X-ray astronomy satellite in human history, was launched in Kenya. After the launch of Uhuru, a series of x-ray telescope satellites were launched, including Rossi X-ray time variety detector, Chandra X-ray Observatory of the United States and Suzaku satellite of Japan, among others. Huiyan's entry in the club of space observers fill China's blank in the development of space X-ray astronomical satellites.

Huiyan is the short name for Hard X-ray Telescope Satellite (HXMT). It has a history of more than 20 years since the initiation of its concept. According to Zhang Shuangnan, director of the Key Laboratory of Particle Astrophysics of CAS, lead scientist of HXMT and council member of the China Society of Space Science, the development process of HXMT satellite was full of difficulties. He introduced that at the initial stage of HXMT research, China was technically weak at reading and dealing with small-signals, which are indispensible for HXMT satellite development. As a result, there are enormous pressure and challenges for satellite development. In the face of difficulties, HXMT team has never held back or given up. After vigorous exploration for countless days and nights, the team tackled technical bottlenecks and successfully developed the HXMT satellites. The successful launch of HXMT satellite on June 15th marked a great leap for China's astronomical observations from ground to observation to ground-and-space observation and a milestone in the history of China's development in its astronomy undertaking.

As China's first space X-ray astronomical satellite, HXMT satellite has many unique features compared with its international counterparts. Zhang Shuangnan mentioned that the designed scientific capability of HXMT satellite includes broadband spectrum X-ray scanning observation covering large space area and large effective area, which can more effectively capture X-ray temporary source in bursty state and also fixed-point observation featuring large area, wide band, high temporal resolution and high-energy resolution of the ability, which can study multi-band X-ray fast light changes of X-ray double stars in large statistical magnitude and rapid changes at the low end of the energy spectrum as well as understand the substance dynamics and high energy radiation process in high-intensity magnetic field of neutron stars and strong gravitational field in black holes. When approaching the end of the satellite development, Zhang Shuangnan led the team to develop the function of detecting gamma ray burst by utilizing the high sensitivity of HXMT.

Zhang Shuangnan suggested that HXMT satellite is expected to make major progress in three areas. First, it may detect a number of new celestial sources mainly made up of black holes and neutron stars; second, it may provide new measurement results of the properties of neutron stars and black holes, such as the magnetic field and mass of neutron stars and the mass and autorotation of black holes; third, it may capture one to two hundreds of gamma rays bursts every year.  "These are our expected scientific results, but in fact, the universe is more complex and miraculous than our imagination. For instance, the ten major scientific discovery of Hubble telescope are not included in the scientists' list of expected results."