A Search for H-Dropout Lyman Break Galaxies at z~12-16
  We present two bright galaxy candidates at z~12-13 identified in our
H-dropout Lyman break selection with 2.3 deg2 near-infrared deep imaging data.
These galaxy candidates, selected after careful screening of foreground
interlopers, have spectral energy distributions showing a sharp discontinuity
around 1.7 um, a flat continuum at 2-5 um, and non-detections at <1.2 um in the
available photometric datasets, all of which are consistent with z>12 galaxy.
An ALMA program targeting one of the candidates shows a tentative 4sigma
[OIII]88um line at z=13.27, in agreement with its photometric redshift
estimate. The number density of the z~12-13 candidates is comparable to that of
bright z~10 galaxies, and is consistent with a recently proposed double
power-law luminosity function rather than the Schechter function, indicating
little evolution in the abundance of bright galaxies from z~4 to 13.
Comparisons with theoretical models show that the models cannot reproduce the
bright end of rest-frame ultraviolet luminosity functions at z~10-13. Combined
with recent studies reporting similarly bright galaxies at z~9-11 and mature
stellar populations at z~6-9, our results indicate the existence of a number of
star-forming galaxies at z>10, which will be detected with upcoming space
missions such as James Webb Space Telescope, Nancy Grace Roman Space Telescope,
and GREX-PLUS.
