Extremely red galaxies at $z=5-9$ with MIRI and NIRSpec: dusty galaxies or obscured AGNs?

Understand

We study a new population of extremely red objects (EROs) recently discovered by JWST based on their NIRCam colors F277W$-$F444W $>1.5$ mag.

• We find 37 EROs in the CEERS field with F444W $<28$ mag and photometric redshifts between $5<z<7$, with median $z=6.9^{+1.0}_{-1.6}$.
• Surprisingly, despite their red long-wavelength colors, these EROs have blue short-wavelength colors (F150W$-$F200W$\sim$0 mag) indicative of bimodal SEDs with a red, steep slope in the rest-frame optical, and a blue, flat slope in the rest-frame UV.
• Moreover, all these EROs are unresolved, point-like sources in all NIRCam bands.