Chinese researchers create the largest deep space neutral hydrogen catalog ever

This panoramic aerial image, captured on July 26, 2023, displays the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) located in Guizhou Province, southwest China.

Beijing, December 13, Xinhua With the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), also known as the "China Sky Eye," a group of Chinese astronomers constructed the most extensive, high-quality catalog of neutral hydrogen (HI) sources outside of our galaxy to date.

One of the most common elements in the universe, hydrogen, is essential to galaxies. The HI makes up a large portion of the interstellar medium in disk galaxies.

Quantifying its abundance and kinematics using the 21-centimeter emission line may help resolve a number of astrophysical questions, including the nature of dark matter and faint, unidentified galaxies, as well as the structure and evolution of the cosmos.

 With 41,741 HI sources found between August 2020 and June 2023, the new catalog outnumbers comparable ones worldwide in terms of both quantity and quality.

The work is a component of the FAST All Sky HI survey (FASHI), an initiative aimed at capturing all of the sky that is visible to the FAST. Over the next five years, more than 100,000 HI sources should be recorded; the current survey results are derived from about 35 percent of the total sky.

Largest single-dish radio telescope in the world, the FAST has a reception area equivalent to thirty regular football fields. On January 11, 2020, FAST formally started operations in a naturally occurring round and deep karst depression in the Guizhou Province of southwest China.

With its greater spectral and spatial resolution, wider coverage, and more dependable and comprehensive data quality, the FAST is the best instrument for high-resolution surveys.

When finished, FASHI will offer the most comprehensive extragalactic hydrogen catalog along with an impartial perspective on the hydrogen content and large-scale structure within the local universe.

The journal SCIENCE CHINA Physics, Mechanics and Astronomy published the findings recently. The study involved contributions from researchers at Peking University, Guizhou University, and the National Astronomical Observatories under the Chinese Academy of Sciences.

Peer reviewing the paper, Lister Staveley-Smith, a professor at the University of Western Australia, referred to their work as "an impressive milestone."