Revolutionizing Space: FASHI’s Record-Breaking Extragalactic HI Catalog via FAST

FAST All Sky HI Survey (FASHI)

The promotional image shows the project about the Five-hundred-meter Aperture Spherical radio Telescope (FAST) All Sky HI survey (FASHI). As the image illustrates, the powerful FAST telescope is observing distant galaxies, recording their HI emission, and revealing the detailed physical properties of the galaxies. Credit: ©Science China Press

The FASHI survey has mapped 35% of its target sky area with the FAST telescope, discovering over 41,000 extragalactic HI sources, and gaining acclaim in the astronomical community.

The FAST All Sky HI survey (FASHI) was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope (FAST), spanning approximately 22000 square degrees of declination between -14 deg and +66 deg, and in the frequency range of 1050-1450 MHz, with the expectation of eventually detecting more than 100000 HI sources.

Between August 2020 and June 2023, FASHI covered more than 7600 square degrees, which is approximately 35% of the total sky observable by FAST. FASHI team has detected a total of 41741 extragalactic HI sources in the frequency range 1305.5-1419.5 MHz. When completed, FASHI team will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

Lister Staveley-Smith, a professor at the University of Western Australia and a peer reviewer of the paper, called their work: “That’s an impressive milestone. That is an extremely important contribution to astronomical research, particularly in the field of galaxy evolution.”

FASHI Sky Distribution of Currently Released 41741 H I Sources

FASHI sky distribution of the currently released 41741 H I sources (in blue dots) in the galactic hemispheres, showing the coarseness of the limits imposed by practical and scheduling constraints. For comparison, ALFALFA α100 (Haynes et al., 2018) and HIPASS galaxies (Koribalski et al., 2004; Meyer et al., 2004; Wong et al., 2006) are also shown with red and green points, respectively. The two black dashed lines indicate the position of the of the galactic plane at galactic latitude b = ±10deg. Credit: ©Science China Press

Hélène Courtois, a professor at the University of Lyon 1, called their work: “The paper is fantastic news for projects like Cosmic Flows!! I didn’t know that the FASHI survey was already going so strongly for 3 years!!

“The quality of the spectra that are shown is exquisite, the completeness of the sample is amazing, and showing the excellent sensitivity of the instrument. The area surveyed in just 3 years gives high hopes that the full sky that can be accessed by the FAST will be covered in record time!

“The paper was a total surprise to me, and reading page after page of the article was just like being a child unwrapping slowly and with delight a Christmas gift.”

The work was recently published in the journal SCIENCE CHINA Physics, Mechanics and Astronomy. Researchers from Guizhou University, the National Astronomical Observatories under the Chinese Academy of Sciences, and Peking University in China contributed to the study.

Reference: “The FAST all sky H i survey (FASHI): The first release of catalog” by Chuan-Peng Zhang, Ming Zhu, Peng Jiang, Cheng Cheng, Jing Wang, Jie Wang, Jin-Long Xu, Xiao-Lan Liu, Nai-Ping Yu, Lei Qian, Haiyang Yu, Mei Ai, Yingjie Jing, Chen Xu, Ziming Liu, Xin Guan, Chun Sun, Qingliang Yang, Menglin Huang, Qiaoli Hao and FAST Collaboration, 8 December 2023, Science China Physics, Mechanics & Astronomy.
DOI: 10.1007/s11433-023-2219-7

1 Comment on "Revolutionizing Space: FASHI’s Record-Breaking Extragalactic HI Catalog via FAST"

  1. What is “HI” in “HI sources”?

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