James Webb Space Telescope Feed Post

PEARLS: JWST counterparts of micro-Jy radio sources in the Time Domain Field Published: 9/22/2023 8:16:35 PM Updated: 9/22/2023 8:16:35 PM

Paper abstract: The Time Domain Field (TDF) near the North Ecliptic Pole in JWST'scontinuous-viewing zone will become a premier "blank field" for extragalacticscience. JWST/NIRCam data in a 16 arcmin^2 portion of the TDF identify 4.4\mum counterparts for 62 of 63 3 GHz sources with S(3 GHz) > 5 {\mu}Jy. Theone unidentified radio source may be a lobe of a nearby Seyfert galaxy, or itmay be an infrared-faint radio source. The bulk properties of the radio-hostgalaxies are consistent with those found by previous work: redshifts range from0.14 to 4.4 with a median redshift of 1.33. The radio emission arises primarilyfrom star formation in ~ 2/3 of the sample and from an active galacticnucleus in ~ 1/3, but just over half the sample shows evidence for an AGNeither in the spectral energy distribution or by radio excess. All but threecounterparts are brighter than magnitude 23 AB at 4.4 \mum, and the exquisiteresolution of JWST identifies correct counterparts for sources for whichobservations with lower angular resolution would mis-identify a nearby brightsource as the counterpart when the correct one is faint and red. Up to 11% ofcounterparts might have been unidentified or misidentified absent NIRCamobservations.