China prepares for flagship X-ray space observatory

BEIJING - The Chinese Academy of Sciences (CAS) declared Friday that it would start to make preparations for a new flagship X-ray space observatory for the research of black holes, neutron stars and quark stars.

The enhanced X-ray Timing and Polarimetry (eXTP) satellite, a successor to the Hard X-ray Modulation Telescope (HXMT) launched in mid June last year, is expected to bring China to a leading level in the world's X-ray astronomy between 2025 to 2035, said Zhang Shuangnan, principal investigator of eXTP from the Institute of High Energy Physics (IHEP).

HXMT, China's first X-ray space telescope with a broad energy band from 1 to 250 keV, can help scientists better understand the evolution of black holes, and the strong magnetic fields and the interiors of pulsars.

"Since we have developed excellent technology and talent in X-ray astronomy, it's highly possible that we can take a leading role in this field if we keep pursuing it with more advanced detection instruments," Zhang said.

According to the astrophysicist, the new X-ray space observatory, designed to consist of a large-area spectroscopic focusing array, a large-area collimator array, a sensitive polarimetry focusing array and a wide field monitor, is expected to have a much better comprehensive performance than previous X-ray astronomic satellites.

"It will have obvious strengths in studying various high-energy celestial bodies, and detecting gamma-ray bursts and electromagnetic signals corresponding to the gravitational waves," Zhang said.

"Its observation will help test general relativity under extreme gravity, quantum electrodynamics under extreme magnetic fields as well as quantum chromodynamics under extreme density," he said.

"The research will eventually contribute to the solving of major scientific questions such as what happens around black holes? What do quantum fluctuations in vacuum state generate? And, what is the state of matter inside neutron stars?" he added.

The IHEP first put forward the concept of an X-ray Timing and Polarimetry (XTP) satellite in 2007. It was later evolved to the eXTP after combining the Large Observatory for X-ray Timing (LOFT) project proposed to the European Space Agency.

Open for cooperation, the eXTP has attracted more than 100 research institutions from over 20 countries and regions, including Italy, Germany, Spain, Britain, France, the Netherlands and Switzerland.

"It is hoped to be the largest international astronomical satellite project initiated and led by China," Zhang said.

"The eXTP is expected to be a flagship mission for astronomy in the decades to come," said Andrea Santangelo, international coordinator of the eXTP mission from Germany. "It will unveil the interactions of matter in the ultra dense conditions expected in the core of the neutron stars, or will let us understand the properties of space time in the strong gravity regions around black holes. It will possibly tell us if Einstein's theory is still correct in extreme conditions of gravity."