A Search for H-Dropout Lyman Break Galaxies at z ∼ 12-16

We present two bright galaxy candidates at z similar to 12-13 identified in our H-dropout Lyman break selection with 2.3 deg(2) 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 mu m, a flat continuum at 2-5 mu m, and nondetections at mu m in the available photometric data sets, all of which are consistent with a z > 12 galaxy. An ALMA program targeting one of the candidates shows a tentative 4 sigma [O iii] 88 mu m line at z = 13.27, in agreement with its photometric redshift estimate. The number density of the z similar to 12-13 candidates is comparable to that of bright z similar to 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 similar to 4 to 13. Comparisons with theoretical models show that the models cannot reproduce the bright end of rest-frame ultraviolet luminosity functions at z similar to 10-13. Combined with recent studies reporting similarly bright galaxies at z similar to 9-11 and mature stellar populations at z similar to 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 the James Webb Space Telescope, Nancy Grace Roman Space Telescope, and GREX-PLUS.

Automated summary

We present two bright galaxy candidates at z similar to 12-13 identified in our H-dropout Lyman break selection. Our results indicate little evolution in the abundance of bright galaxies from z similar to 4 to 13.