Probing Intra-Halo Light with Galaxy Stacking in CIBER Images
  We study the stellar halos of $0.2\lesssim z \lesssim 0.5$ galaxies with
stellar masses spanning $M_*\sim 10^{10.5}$ to $10^{12}M_\odot$ (approximately
$L_*$ galaxies at this redshift) using imaging data from the Cosmic Infrared
Background Experiment (CIBER). A previous CIBER fluctuation analysis suggested
that intra-halo light (IHL) contributes a significant portion of the
near-infrared extragalactic background light (EBL), the integrated emission
from all sources throughout cosmic history. In this work, we carry out a
stacking analysis with a sample of $\sim$30,000 Sloan Digital Sky Survey (SDSS)
photometric galaxies from CIBER images in two near-infrared bands (1.1 and 1.8
$\mu$m) to directly probe the IHL associated with these galaxies. We stack
galaxies in five sub-samples split by brightness, and detect an extended galaxy
profile, beyond the instrument point spread function (PSF), derived by stacking
stars. We jointly fit a model for the inherent galaxy light profile, plus
large-scale one- and two-halo clustering to measure the extended galaxy IHL. We
detect non-linear one-halo clustering in the 1.8 $\mu$m band, at a level
consistent with numerical simulations. Our results on the galaxy profile
suggest that $\sim 50\%$ of the total galaxy light budget in our galaxy sample
resides in the outskirts of the galaxies at $r > 10$ kpc. We describe this
extended emission as IHL and and are able to study how this fraction evolves
with cosmic time. These results are new in the near-infrared wavelength at the
$L_*$ mass scale, and suggest that IHL has a significant contribution to the
integrated galactic light, and to the amplitude of large-scale background
fluctuations.
