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| Auteurs principaux: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2026
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| Accès en ligne: | https://arxiv.org/abs/2605.23686 |
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| _version_ | 1866910248249327616 |
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| author | Xu, Chen Jing, Yingjie Wang, Jie Zou, Hu Du, Wei Yu, Niankun Guo, Hong Liu, Zerui Chen, Qingze Liang, Tiantian Hou, Zhipeng Xu, Yiwei Li, Xiao Hu, Hui-Jie Liu, Ziming Zhao, Pinsong Fang, Taotao Gao, Liang Guo, Qi Gu, Qiusheng Jiang, Zhen Kang, Xi Kong, Xu Li, Cheng Pan, Jun Wang, Tao Zhou, Yanrui Wang, Wenting Wang, Jing |
| author_facet | Xu, Chen Jing, Yingjie Wang, Jie Zou, Hu Du, Wei Yu, Niankun Guo, Hong Liu, Zerui Chen, Qingze Liang, Tiantian Hou, Zhipeng Xu, Yiwei Li, Xiao Hu, Hui-Jie Liu, Ziming Zhao, Pinsong Fang, Taotao Gao, Liang Guo, Qi Gu, Qiusheng Jiang, Zhen Kang, Xi Kong, Xu Li, Cheng Pan, Jun Wang, Tao Zhou, Yanrui Wang, Wenting Wang, Jing |
| contents | The Hundred-deg$^2$ HI Deep (HD$^2$) survey carried out with the Five-hundred-meter Aperture Spherical Telescope (FAST) is planned to map a contiguous region within the DESI DR1 footprint, achieving an effective integration time of 20 minutes for each pointing and a uniform detection sensitivity of 0.28 mJy beam$^{-1}$ at 4.8 km s$^{-1}$ resolution. We present early results from the pilot HD$^2$ survey: a 10 deg$^2$ field overlapping with HSC-SSP and the DESI EDR SV3, observed with an integration time of 7.3 minutes per beam and the rms of 0.45 mJy beam$^{-1}$ at 4.8 km s$^{-1}$ resolution. We identify 339 HI sources at $z<0.09$, corresponding to $\sim$34 detections per deg$^2$, nearly six times higher than the detection rate of the wide-field surveys. Optical counterparts are primarily identified using DESI redshifts, yielding a matching rate and correctness exceeding 90% for galaxies with $r<19.5$ mag, a substantial improvement over SDSS. Under the constraint of $r < 17.8$ mag and $0.01 < z < 0.05$, nearly 50% of galaxies in the DESI BGS samples have HI detections in this pilot survey. The optical properties of these HI-detected galaxies span nearly the entire parameter range of the DESI sample. The gas fraction scaling relations versus stellar mass, stellar mass surface density, NUV-r, and specific star formation rate are consistent with previous surveys, e.g., ALFALFA, DINGO, and xGASS. These results justify the feasibility of the full HD$^2$ survey, which will build a high-completeness HI census over a contiguous area to probe the cold gas scaling relations of galaxies over different scales. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_23686 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | The FAST Hundred-Deg$^2$ HI Deep (HD$^2$) Survey: Early Results from the Pilot Survey Xu, Chen Jing, Yingjie Wang, Jie Zou, Hu Du, Wei Yu, Niankun Guo, Hong Liu, Zerui Chen, Qingze Liang, Tiantian Hou, Zhipeng Xu, Yiwei Li, Xiao Hu, Hui-Jie Liu, Ziming Zhao, Pinsong Fang, Taotao Gao, Liang Guo, Qi Gu, Qiusheng Jiang, Zhen Kang, Xi Kong, Xu Li, Cheng Pan, Jun Wang, Tao Zhou, Yanrui Wang, Wenting Wang, Jing Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics The Hundred-deg$^2$ HI Deep (HD$^2$) survey carried out with the Five-hundred-meter Aperture Spherical Telescope (FAST) is planned to map a contiguous region within the DESI DR1 footprint, achieving an effective integration time of 20 minutes for each pointing and a uniform detection sensitivity of 0.28 mJy beam$^{-1}$ at 4.8 km s$^{-1}$ resolution. We present early results from the pilot HD$^2$ survey: a 10 deg$^2$ field overlapping with HSC-SSP and the DESI EDR SV3, observed with an integration time of 7.3 minutes per beam and the rms of 0.45 mJy beam$^{-1}$ at 4.8 km s$^{-1}$ resolution. We identify 339 HI sources at $z<0.09$, corresponding to $\sim$34 detections per deg$^2$, nearly six times higher than the detection rate of the wide-field surveys. Optical counterparts are primarily identified using DESI redshifts, yielding a matching rate and correctness exceeding 90% for galaxies with $r<19.5$ mag, a substantial improvement over SDSS. Under the constraint of $r < 17.8$ mag and $0.01 < z < 0.05$, nearly 50% of galaxies in the DESI BGS samples have HI detections in this pilot survey. The optical properties of these HI-detected galaxies span nearly the entire parameter range of the DESI sample. The gas fraction scaling relations versus stellar mass, stellar mass surface density, NUV-r, and specific star formation rate are consistent with previous surveys, e.g., ALFALFA, DINGO, and xGASS. These results justify the feasibility of the full HD$^2$ survey, which will build a high-completeness HI census over a contiguous area to probe the cold gas scaling relations of galaxies over different scales. |
| title | The FAST Hundred-Deg$^2$ HI Deep (HD$^2$) Survey: Early Results from the Pilot Survey |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2605.23686 |