The FAST All Sky H I Survey (FASHI): the first release of catalog

Abstract: The FAST All Sky HI survey (FASHI, read as /fɑːʃ/ or 法师 in Chinese) 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 1000-1500 MHz, with the expectation of eventually detecting more than 100000 HI sources. Between August 2020 and June 2023, FASHI had covered more than 7600 square degrees, which is approximately 35% of the total sky observable by FAST. It has a median detection sensitivity of around 0.76 mJy/beam and a spectral line velocity resolution of ~6.4 km/s at a frequency of ~1.4 GHz. As of now, a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz, corresponding to a redshift limit of z<0.09. By cross-matching FASHI sources with the Siena Galaxy Atlas (SGA) and the Sloan Digital Sky Survey (SDSS) catalogs, we found that 16972 (40.7%) sources have spectroscopic redshifts and 10975 (26.3%) sources have only photometric redshifts. Most of the remaining 13794 (33.0%) HI sources are located in the direction of the Galactic plane, making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar sources. Based on current survey results, the FASHI survey is an unprecedented blind extragalactic HI survey. It has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy Fast ALFA Survey (ALFALFA). When completed, FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

FASHI technical details:

Parameters Values
Planed RA range 0h ≤ RA ≤ 24h (see Figure 1)
Planed DEC range -14◦ ≤ DEC ≤ +66◦ (see Figure 1)
Current DEC range 0h ≤ RA ≤ 17.3h, 22h ≤ RA ≤ 24h
Current DEC range -6◦ ≤ DEC ≤ 0◦, 30◦ ≤ DEC ≤ +66◦
Receiver 19-beam array
Polarizations per beam 2 linear (XX, YY)
Beam size (FWHM) 2.9 arcmin at 1420 MHz
Gain 13-17 K/Jy
Tsys 16-19 K
Total frequency coverage 1050-1450 MHz
Released frequency range 1305.5-1419.5 MHz (in this work)
cz range 200-26323 km/s (in this work)
Bandwidth (total) 400 MHz
Spectral channels 65536 (before smoothing)
Channel spacing 7.629 kHz or 1.6 km/s
Spectral resolution 6.4 km/s (after smoothing)
Spectral median rms ∼1.50 mJy at 6.4 km/s resolution
Map median sensitivity ∼0.76 mJy/beam at 6.4 km/s resolution

Supplementary materials:

  1. The full paper can be downloaded in The FAST All Sky HI Survey (FASHI): the first release of catalog
  2. The complete Table 2 containing 41741 sources can be accessed in FASHI extragalactic HI source catalog
  3. The complete Table 3 containing 3620 sources can be accessed in FASHI and ALFALFA cross-matching catalog
  4. The complete Table 4 containing 14072 sources can be accessed in The identified optical counterparts from the SGA catalog
  5. The complete Table 5 containing 2900 sources can be accessed in The identified optical counterparts from the SDSS spectroscopic catalog
  6. The complete Table 6 containing 10975 sources can be accessed in The identified optical counterparts from the SDSS photometric catalog

Publications related to FASHI:

  1. Zhang, Chuan-Peng; Cheng, Cheng; Zhu, Ming; Jiang, Peng “FASHI: A search for extragalactic OH megamasers with FAST” 2024arXiv240115397Z

  2. Zhang, Chuan-Peng; Zhu, M. ; Jiang, P.; Cheng, C.; Wang, J.; Wang, J.; Xu, J. -L.; Liu, X. -L.; Yu, N. -P.; Qian, L.; Yu, H.; Ai, M.; Jing, Y.; Xu, C.; Liu, Z.; Guan, X.; Sun, C.; Yang, Q.; Huang, M.; Hao, Q.; FAST Collaboration “The FAST all sky HI survey (FASHI): The first release of catalog” 2024SCPMA..6719511Z

  3. Ai, Mei; Zhu, Ming; Xu, Jin-long; Wang, Jie; Jing, Ying-jie; Yu, Hai-yang; Jiang, Peng “High-sensitivity H I mapping of NGC 4449 with FAST” 2023MNRAS.524.2911A

  4. Zhou, Ruilei; Zhu, Ming; Yang, Yanbin; Yu, Haiyang; Yuan, Lixia; Jiang, Peng; Xi, Wenzhe “FAST Reveals New Evidence for M94 as a Merger” 2023ApJ…952..130Z

  5. Liu, Yao; Zhu, Ming; Yu, Haiyang; Ai, Mei; Jiang, Peng; Liu, Siqi; Yuan, Lixia “FAST discovery of long tidal tails in NGC 4490/85” 2023MNRAS.523.3905L

  6. Yu, Haiyang; Zhu, Ming; Xu, Jin-Long; Ai, Mei; Jiang, Peng; Yang, Yanbin “High-sensitivity H I image of diffuse gas and new tidal features in M51 observed by FAST” 2023MNRAS.521.2719Y

  7. Yu, Nai-Ping; Zhu, Ming; Xu, Jin-Long; Zhang, Chuan-Peng; Liu, Xiao-Lan; Jiang, Peng; Wang, Jun-Jie “FAST discovery of an extra plume in DDO 168” 2023MNRAS.521..737Y

  8. Zhang, Chuan-Peng; Jiang, Peng; Zhu, Ming; Pan, Jun; Cheng, Cheng; Liu, Hong-Fei; Zhu, Yan; Sun, Chun; FAST Collaboration “Performance of FAST with an Ultra-Wide Bandwidth Receiver at 500-3300 MHz” 2023RAA….23g5016Z

  9. Zhu, Ming; Yu, Haiyang; Wang, Jie; Xu, Jin-Long; Du, Wei; Yuan, Lixia; Wang, Jing; Jing, Yingjie; Ai, Mei; Jiang, Peng “FAST Discovery of a Long H I Accretion Stream toward M106” 2021ApJ…922L..21Z

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