  The first few hundred Myrs at $z>10$ mark the last major uncharted epoch in
the history of the Universe, where only a single galaxy (GNz11 at $z\approx11$)
is currently spectroscopically confirmed. Here we present a search for luminous
$z>10$ galaxies with $JWST$/NIRCam photometry spanning $\approx1-5\mu$m and
covering 49 arcmin$^{2}$ from the public Early Release Science programs (CEERS
and GLASS). Our most secure candidates are two $M_{\rm{UV}}\approx-21$ systems:
GLASS-z12 and GLASS-z10. These galaxies display abrupt $\gtrsim1.8$ mag breaks
in their spectral energy distributions, consistent with complete absorption of
flux bluewards of Lyman-$\alpha$ that is redshifted to $z=12.4^{+0.1}_{-0.3}$
and $z=10.4^{+0.4}_{-0.5}$. Lower redshift interlopers such as quiescent
galaxies with strong Balmer breaks would be comfortably detected at $>5\sigma$
in multiple bands where instead we find no flux. From SED modeling we infer
that these galaxies have already built up $\sim 10^9$ solar masses in stars
over the $\lesssim300-400$ Myrs after the Big Bang. The brightness of these
sources enable morphological constraints. Tantalizingly, GLASS-z10 shows a
clearly extended exponential light profile, potentially consistent with a disk
galaxy of $r_{\rm{50}}\approx0.7$ kpc. These sources, if confirmed, join GNz11
in defying number density forecasts for luminous galaxies based on Schechter UV
luminosity functions, which require a survey area $>10\times$ larger than we
have studied here to find such luminous sources at such high redshifts. They
extend evidence from lower redshifts for little or no evolution in the bright
end of the UV luminosity function into the cosmic dawn epoch, with implications
for just how early these galaxies began forming. This, in turn, suggests that
future deep $JWST$ observations may identify relatively bright galaxies to much
earlier epochs than might have been anticipated.
