Speaker
Description
We investigate the morphology from UV to optical of eight little red dots (LRDs) selected from the JWST UNCOVER survey, applying a new technique (GalfitS) to simultaneously fit the morphology and spectra energy distribution using multiband NIRCam images covering ~ 1-4 ${\mu m}$. For the majority of LRDs (7/8) in our sample, the morphology in all bands are dominated by an unresolved point source, with no concentric host galaxy component detected. We detect the host galaxy in only one LRD, MSAID38108 at z=4.96, which has a stellar mass of ${{\rm log}\ (M_*/M_{\odot})=8.66}$, an effective radius of 0.66 kpc, and a Sersic index of n=0.71. Based on the black hole masses estimated from the broad Ha emission line, the derived stellar mass limits are at least a factor of 10 lower than expected from the ${z\approx 0}$ scaling relation. Intriguingly, four of the LRDs (50% of the sample) show extended, off-centered emission that is particularly prominent in the bluer bands. The SED shape of the off-centered emission suggests a combination of foreground low-redshift interlopers, companion galaxies, and/or nebular emission originating from low-density, low-metallicity gas ionized by the LRDs.