We use deep F275W imaging from the Hubble Deep UV Legacy Survey (HDUV) and G280 grism spectroscopy from HST/WFC3, along with new and archival optical spectra from Keck/DEIMOS, to search for candidate ionizing sources in the GOODS-N field at z ~ 2.5 - 3. Spectroscopic identification of our UV-selected sources are 99% complete to F275W = 25.5 in the region of the UV imaging, and we identify 6 potential ionizing galaxies or AGNs at z ~ 3. By far the brightest of these is a z = 2.583 AGN that totally dominates the ionizing flux in the region, with a specific ionizing volume emissivity at 912A˚ of ϵ912 = 8.31.427×1024 erg s−1 Hz−1 Mpc−3. Based on our spectroscopic data, we find four candidates are contaminated by foreground galaxies at z ~ 0.5 - 0.7. At ϵ912 = 2.20.47.2×1023 erg s−1 Hz−1 Mpc−3, the remaining candidate galaxy's contribution to the ionizing background lies well below the flux required to ionize the intergalactic medium at z ~ 2.5 - 3, consistent with previous observations that show AGNs provide the bulk of the ionizing background at these redshifts.
@article{arxiv.1806.08798,
title = {z ~ 2.5 - 3 Ionizers in the GOODS-N Field},
author = {L. H. Jones and A. J. Barger and L. L. Cowie and P. A. Oesch and E. M. Hu and A. Songaila and R. P. Naidu},
journal= {arXiv preprint arXiv:1806.08798},
year = {2018}
}
Comments
14 pages, 11 figures. Accepted for publication in ApJ