Early results from GLASS-JWST. XIII. A faint, distant, and cold brown dwarf

Understand

We present the serendipitous discovery of a late T-type brown dwarf candidate in JWST NIRCam observations of the Early Release Science Abell 2744 parallel field.

• The discovery was enabled by the sensitivity of JWST at 4~$\mu$m wavelengths and the panchromatic 0.9--4.5~$\mu$m coverage of the spectral energy distribution.
• The unresolved point source has magnitudes F115W = 27.95$\pm$0.15 and F444W = 25.84$\pm$0.01 (AB), and its F115W$-$F444W and F356W$-$F444W colors match those expected for other, known T dwarfs.
• We can exclude it as a reddened background star, high redshift quasar, or very high redshift galaxy.