# The Super Eight Galaxies: Properties of a Sample of Very Bright Galaxies at $7 < z < 8$

## TL;DR

This study characterizes eight very bright high-redshift galaxies at $7<z<8$, analyzing their properties, sizes, masses, and their consistency with the UV luminosity function, providing insights into galaxy evolution during reionization.

## Contribution

First detailed analysis of a bright galaxy sample at $7<z<8$ combining HST and Spitzer data, confirming and expanding previous high-redshift galaxy candidates.

## Key findings

- Six galaxies confirmed at $7.1<z<8.0$ with new data.
- Sizes consistent with size evolution models.
- Mean stellar mass around 10^10 solar masses.

## Abstract

We present the Super Eight galaxies - a set of very luminous, high-redshift ($7.1<z<8.0$) galaxy candidates found in Brightest of Reionizing Galaxies (BoRG) Survey fields. The original sample includes eight galaxies that are $Y$-band dropout objects with $H$-band magnitudes of $m_H<25.5$. Four of these objects were originally reported in Calvi et al. 2016. Combining new Hubble Space Telescope (HST) WFC3/F814W imaging and $Spitzer$ IRAC data with archival imaging from BoRG and other surveys, we explore the properties of these galaxies. Photometric redshift fitting places six of these galaxies in the redshift range of $7.1<z<8.0$, resulting in three new high-redshift galaxies and confirming three of the four high-redshift galaxy candidates from Calvi et al. 2016. We calculate the half-light radii of the Super Eight galaxies using the HST F160W filter and find that the Super Eight sizes are in line with typical evolution of size with redshift. The Super Eights have a mean mass of log(M$_*$/M$_\odot$) $\sim10$, which is typical for sources in this luminosity range. Finally, we place our sample on the UV $z\sim8$ luminosity function and find that the Super Eight number density is consistent with other surveys in this magnitude and redshift range.