8.01.2024

ASHI 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 a100 (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.

The field of extragalactic astronomy has witnessed a significant advancement with the FAST All Sky HI survey (FASHI), a project designed to utilize the unique capabilities of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). This ambitious survey, spanning an impressive 22000 square degrees of the sky, aims to revolutionize our understanding of the universe's HI content and its large-scale structure.

FAST, renowned for its massive aperture, offers an unparalleled view of the cosmos in the radio spectrum. FASHI's coverage extends across declinations from -14 degrees to +66 degrees and operates within the frequency range of 1050-1450 MHz. This broad scope is pivotal in pursuing the survey's goal of detecting over 100,000 HI sources.

Since its commencement in August 2020, FASHI has made substantial progress. As of June 2023, the survey has scanned over 7600 square degrees, roughly 35% of the total sky observable by FAST. This endeavor has already yielded remarkable results, with the detection of 41,741 extragalactic HI sources within the frequency range of 1305.5-1419.5 MHz.

The significance of FASHI's findings is not lost on experts in the field. Lister Staveley-Smith, a professor at the University of Western Australia and a peer reviewer of the study, lauded the project's achievements. "That's an impressive milestone," he remarked, emphasizing the study's vital contribution to astronomical research, especially in understanding galaxy evolution.

Echoing these sentiments, Helene Courtois, a professor at the University of Lyon 1, expressed her enthusiasm for the project's impact on related research initiatives like Cosmic Flows. "The paper is a fantastic news for projects like Cosmic Flows!! I didn't know that the FASHI survey was already going so strongly since 3 years!!" Courtois commented on the quality and completeness of the data, highlighting the instrument's excellent sensitivity and the survey's rapid progress. She likened reading the study to "being a child unwrapping slowly and with delight a Christmas gift."

The recent publication of FASHI's work in the journal SCIENCE CHINA Physics, Mechanics and Astronomy marks a significant milestone. This comprehensive study involved collaboration among researchers from Guizhou University, the National Astronomical Observatories under the Chinese Academy of Sciences, and Peking University in China. Their collective efforts have not only advanced our understanding of the local universe but have also set a new standard in the field of extragalactic HI surveys.

As FASHI continues its journey, the astronomical community eagerly anticipates the completion of this monumental survey. Once finalized, FASHI will provide the largest extragalactic HI catalog, offering an unprecedented objective view of HI content and large-scale structures in our local universe. This endeavor stands as a testament to the power of international collaboration and the relentless pursuit of knowledge in the ever-expanding field of astronomy.Research Report:The FAST all sky H I survey (FASHI): The first release of catalog

Quelle: SD