Luminous and High Stellar Mass Candidate Galaxies at z ~ 8 Discovered in CANDELS
Abstract
One key goal of the Hubble Space Telescope Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey is to track galaxy evolution back to z ~ 8. Its two-tiered "wide and deep" strategy bridges significant gaps in existing near-infrared surveys. Here we report on z ~ 8 galaxy candidates selected as F105W-band dropouts in one of its deep fields, which covers 50.1 square arcmin to 4 ks depth in each of three near-infrared bands in the Great Observatories Origins Deep Survey southern field. Two of our candidates have J<26.2 mag, and are > 1 mag brighter than any previously known F105W-dropouts. We derive constraints on the bright-end of the rest-frame ultraviolet luminosity function of galaxies at z ~ 8, and show that the number density of such very bright objects is higher than expected from the previous Schechter luminosity function estimates at this redshift. Another two candidates are securely detected in Spitzer Infrared Array Camera images, which are the first such individual detections at z ~ 8. Their derived stellar masses are on the order of a few x 10^9 M_sun, from which we obtain the first measurement of the high-mass end of the galaxy stellar mass function at z ~ 8. The high number density of very luminous and very massive galaxies at z ~ 8, if real, could imply a large stellar-to-halo mass ratio and an efficient conversion of baryons to stars at such an early time.
Keywords
Cite
@article{arxiv.1112.6406,
title = {Luminous and High Stellar Mass Candidate Galaxies at z ~ 8 Discovered in CANDELS},
author = {Haojing Yan and Steven L. Finkelstein and Kuang-Han Huang and Russell E. Ryan and Henry C. Ferguson and Anton M. Koekemoer and Norman A. Grogin and Mark Dickinson and Jeffrey A. Newman and Rachel S. Somerville and Romeel Dave and S. M. Faber and Casey Papovich and Yicheng Guo and Mauro Giavalisco and Kyoung-soo Lee and Naveen Reddy and Asantha R. Cooray and Brian D. Siana and Nimish P. Hathi and Giovanni G. Fazio and Matthew Ashby and Benjamin J. Weiner and Ray A. Lucas and Avishai Dekel and Laura Pentericci and Christopher J. Conselice and Dale D. Kocevski and Kamson Lai},
journal= {arXiv preprint arXiv:1112.6406},
year = {2015}
}
Comments
to appear in ApJ December 20, 2012 issue