HAWC J0630+186 Could Not Be Powered by PSR J0630+19

Abstract 3HWC J0630+186 is one of the very-high-energy gamma-ray sources listed in the third High-Altitude Water Cherenkov catalog; however, its origin remains unidentified. The only plausible counterpart is PSR J0630+19, which is offset from the center of 3HWC J0630+186. Several TeV halos around pulsars are currently considered among the most dominant TeV–PeV gamma-ray sources. PSR J0630+19 was first discovered in an Arecibo survey as a normal-period pulsar, but its age and spin-down luminosity are not available, making it difficult to assess whether it is associated with 3HWC J0630+186. Using awarded observing time on the Five-hundred-meter Aperture Spherical radio Telescope, we conducted follow-up timing observations of PSR J0630+19 for over 1 yr. Through pulsar timing analysis, we obtained a more precise position and derived key parameters. These parameters indicate that PSR J0630+19 is an old pulsar with a spin-down luminosity too low to power the very-high-energy emission from 3HWC J0630+186.