Unknown origin of the MIRI F770W excess flux in JADES-GS-z14-0

Determine the physical origin of the excess JWST/MIRI F770W (7.7 µm) flux observed in JADES-GS-z14-0, distinguishing the relative contributions of rest-frame optical nebular emission lines ([OIII] λλ4959,5007 and Hβ) and stellar or nebular continuum components, to reduce the current uncertainty in stellar mass estimates derived from spectral energy distribution fitting.

Background

JADES-GS-z14-0 is a luminous z≈14 galaxy with MIRI F770W detection showing excess flux likely associated with strong rest-frame optical lines. However, the detailed origin of this excess is not securely identified, which propagates into large uncertainties in the SED-derived stellar mass.

Clarifying the origin of the F770W excess is crucial for robustly constraining the galaxy’s stellar mass and other physical parameters, as current modeling outcomes depend sensitively on assumptions about nebular versus continuum contributions.