Jenam 2011To gain an advantage over US space agency NASA, Chinese scientists aim to develop a next-generation space observatory to search for dark matter. The ambitious project – known as the Very Large Area Gamma-Ray Space Telescope, or VLAST – is currently in its early stages of development.
Scientists plan to put the telescope into orbit by the end of the decade. They are, however, awaiting approval from the Chinese government, according to media reports.
Researchers from Nanjing Purple Mountain Observatory, Hefei University of Science and Technology and Lanzhou Institute of Modern Physics collaborated on the project.
With the development of this telescope, scientists hope to achieve ten times the sensitivity of NASA’s Fermi Large Area Telescope.
NASA’s Fermi Large Area Telescope is the most sensitive gamma-ray telescope in the world. It is the successor to NASA’s Compton-Gamma-ray Observatory, which operated from 1991 to 1999.
According to NASA, Fermi’s field of view and its ability to study the sky were twice as large and 30 times more sensitive than any of Compton’s instruments. NASA defined Fermi as “a partnership of astrophysics and particle physics”, NASA having developed it in collaboration with the United States Department of Energy.
The project also included international partners from France, Germany, Italy, Japan, and Sweden, as well as other institutions in the United States.
Why gamma rays?
Gamma rays are the most energetic form of light, with over a billion times the energy of visible light, and are extremely difficult to detect. Phenomena such as the explosion of stars and black holes frequently emit gamma rays.
Gamma rays allow researchers to peer into the outer reaches of the universe and witness a variety of phenomena, including rapidly rotating neutron stars and super-dense black holes.
They are also indirect evidence for dark matter, which accounts for the majority of matter in the universe but has puzzled scientists for decades.
Astronomers believe that dark matter must exist to provide the gravitational pull needed to hold galaxies and clusters together. When dark matter particles collide, they theoretically decay or annihilate, producing gamma rays that telescopes can observe.
According on the NASA website, “Gamma rays sent out by objects embedded within galaxies greatly affect the space around those objects and how those galaxies evolve. By studying gamma rays, NASA can better understand how the laws of physics work in the extreme environments of the distant universe.
How will the Chinese telescope work?
VLAST will use exceptional energy resolution to search for signs of dark matter particles in the cosmic gamma-ray spectrum between 0.3 giga-electron volts and 20 tera-electron volts, according to the report.
The Chinese journal Acta Astronomica Sinica unveiled the project on May 26. They also said that VLAST would focus on our galactic center to investigate “a puzzling surplus of gamma radiation, which could be explained by the presence of self-annihilating dark matter.”
VLAST will also study hot topics in high-energy astronomy, such as gamma-ray bursts, X-ray binary stars, the origin of cosmic rays, and the search for dark matter.
According to its preliminary design, VLAST will have three types of detectors. They would separate the gamma photons from other particles entering the telescope, then precisely measure the energy and trajectory of the gamma photons. The sensors could weigh 16 tons, much more than a typical space telescope.
“We would need a Long March 5 rocket to send it into orbit,” Fan Yizhong of the Purple Mountain Observatory was quoted by the South China Morning Post as saying. Chinese researchers are currently working on the core technology for the project. “From the electronics to the detectors and the satellite platform, it has been difficult,” Fan had observed during an online event.
“We will need at least ten years to prepare – if the government decides to fund us,” he added. In March, the researchers submitted their VLAST proposal to the Chinese Academy of Sciences, which has yet to issue a judgment.
The three main methods of searching for dark matter are collider, direct and indirect detection. China is already employing the third way with its first dark matter probe, the Dark Matter Particle Explorer, known as Wukong or Monkey King. For more than six years, it has been operating in low Earth orbit.
The project is the result of a collaboration between Italian, Swiss and Chinese research organizations and universities led by researchers from the Purple Mountain Observatory.
He found a spectral break at about 0.9 tera-electron-volts, which provided information about the demolition or destruction of dark matter particles.
