Very bright, very blue, and very red: JWST CAPERS analysis of highly luminous galaxies with extreme UV slopes at $\mathbf{z = 10}$

Understand

We present JWST/NIRSpec PRISM observations of three luminous ($M_{\rm UV}<-20$) galaxies at $z\sim10$ observed with the CAPERS Cycle 3 program.

• These galaxies exhibit extreme UV slopes compared to typical galaxies at $z=10$.
• Of the three sources, two of them are a close pair (0.22 - arcsec) of blue galaxies at $z=9.800\pm0.003$ and $z=9.808\pm0.002$ with UV slopes of $\beta=-2.87\pm0.15$ and $\beta=-2.46\pm0.10$ respectively, selected from PRIMER COSMOS NIRCam imaging.
• We perform spectrophotometric modeling of the galaxies which suggests extremely young stellar ages and a lack of dust attenuation.