BEIJING, Dec. 13 (Xinhua) — Using the Five Hundred Meter Aperture Spherical Radio Telescope (FAST), or “China's Eye of Heaven,” a team of Chinese astronomers has compiled the largest catalog of high-quality sources of neutral hydrogen (HI) beyond our galaxy.
Hydrogen, the most abundant element in the universe, is a key component of galaxies. In disk galaxies, neutral hydrogen is an important component of the interstellar medium.
Measuring their abundance and kinematics using the 21 centimeter emission line could make it possible to answer a number of astrophysical questions, such as the possible properties of dark matter, unknown faint galaxies, and the structure and evolution of the cosmos.
The new catalog contains a total of 41,741 HI sources discovered between August 2020 and June 2023, exceeding in quantity and quality similar catalogs around the world.
This work is part of a project called the FAST All Sky HI Survey (FASHI), which aims to cover the entire sky visible to FAST. The results of the current study come from about 35% of the entire sky and are expected to detect more than 100,000 HI sources in the next five years.
FAST is the world's largest single-disk radio telescope with a reception area equivalent to 30 standard football fields. FAST officially began operations on January 11, 2020 in a naturally deep and circular karst depression in Guizhou Province, southwest China.
FAST is an optimal tool for HI studies with higher spectral and spatial resolution, greater coverage, and more reliable and comprehensive data quality.
Once completed, FASHI will provide the largest extragalactic HI catalog as well as an objective view of HI content and large-scale structure in the local universe.
The results were recently published in the journal Science China: Physics, Mechanics and Astronomy. Researchers from Guizhou University, the National Astronomical Observatories of the Chinese Academy of Sciences and Beijing University all contributed to the study. END