FAST Ultra-Deep Survey (FUDS): Data Release for FUDS0

We have used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to make a blind ultra-deep survey for neutral hydrogen (HI). We present the complete results from the first of six fields (FUDS0). This observation of 95 hours allowed us to achieve a high sensitivity ($\sim 50~\mu$Jy beam$^{-1}$) and a high frequency resolution (22.9 kHz) over an area of 0.72 deg$^2$. We detected 128 galaxies in HI distributed over the redshift range of $0<z<0.4$ with HI masses in the range of $6.67 \leq \log(M_{\rm HI}/h_{70}^{-2} \rm M_\odot) \leq 10.92$, and three faint high-velocity clouds (HVCs) with peak column density of $N_{\rm HI} \leq 3.1 \times 10^{17}$ cm$^{-2}$. Of the galaxies, 95 are new detections and six have $z > 0.38$, where no unlensed HI emission has previously been directly detected. Estimates of completeness and reliability are presented for the catalog. Consistency of continuum and HI flux estimates with NVSS and AUDS, respectively, confirms the accuracy of calibration method and data reduction pipeline developed for the full FUDS survey.