FAST Ultra-Deep Survey: Data Release for FUDS0

Abstract We have used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to conduct a blind ultradeep survey for neutral hydrogen (H i ). We present the complete results from the first of six fields (FUDS0). These observations of 95 hr allowed us to achieve a high-sensitivity (∼50 μ Jy beam −1 ) and a high-frequency resolution (22.9 kHz) over an area of 0.72 deg 2 . We detected 128 galaxies in H i distributed over the redshift range of 0 &lt; z &lt; 0.4, with H i masses in the range of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>6.67</mml:mn> <mml:mo>≤</mml:mo> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mi>M</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">I</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="true">/</mml:mo> <mml:msubsup> <mml:mi>h</mml:mi> <mml:mn>70</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:msubsup> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mo>≤</mml:mo> <mml:mn>10.92</mml:mn> </mml:math> , and three faint high-velocity clouds, with a peak column density of N H i ≤ 3.1 × 10 17 cm −2 . Of the galaxies, 95 are new detections and six have z &gt; 0.38, where no unlensed H i emission has previously been directly detected. Estimates of completeness and reliability are presented for the catalog. The consistency of continuum and H i flux estimates with the NRAO VLA Sky Survey and the Arecibo Ultra-Deep Survey, respectively, confirms the accuracy of the calibration method and data reduction pipeline developed for the full FAST Ultra-Deep Survey.