A Pilot for a VLA HI Deep Field
  High-resolution 21-cm HI deep fields provide spatially and kinematically
resolved neutral gas maps at different redshifts, which are key to
understanding galaxy evolution across cosmic time and testing predictions of
cosmological simulations. Here we present results from a pilot for the COSMOS
HI Large Extragalactic Survey (CHILES) done with the Karl G. Jansky Very Large
Array (VLA). We take advantage of the newly expanded capabilities of the
telescope to probe the redshift interval 0<z<0.193 in one observation. We
observe the COSMOS field for 50 hours, which contains 413 galaxies with optical
spectroscopic redshifts in the imaged field of view of 34' x 34' and the
observed redshift interval. We have detected neutral hydrogen gas in 33
galaxies in different environments spanning the probed redshift range,
including three without a previously known spectroscopic redshift. The
detections have a range of HI and stellar masses, indicating the diversity of
galaxies we are probing. We discuss the observations, data reduction, results
and highlight interesting detections. We find that the VLA's B-array is the
ideal configuration for HI deep fields since its long spacings mitigate RFI.
This pilot shows that the VLA is ready to carry out such a survey, and serves
as a test for future HI deep fields planned with other SKA pathfinders.
