Bubble mapping with the Square Kilometer Array -- I. Detecting galaxies
  with Euclid, JWST, WFIRST and ELT within ionized bubbles in the intergalactic
  medium at z>6
  The Square Kilometer Array is expected to provide the first tomographic
observations of the neutral intergalactic medium at redshifts z>6 and pinpoint
the locations of individual ionized bubbles during early stages of cosmic
reionization. In scenarios where star-forming galaxies provide most of the
ionizing photons required for cosmic reionization, one expects the first
ionized bubbles to be centered on overdensities of such galaxies. Here, we
model the properties of galaxy populations within isolated, ionized bubbles
that SKA-1 should be able to resolve at z=7-10, and explore the prospects for
galaxy counts within such structures with various upcoming near-infrared
telescopes. We find that, for the bubbles that are within reach of SKA-1
tomography, the bubble volume is closely tied to the number of ionizing photons
that have escaped from the galaxies within. In the case of galaxy-dominated
reionization, galaxies are expected to turn up above the spectroscopic
detection threshold of JWST and ELT in even the smallest resolvable bubbles at
redshifts z=10 or below. The prospects of detecting galaxies within these
structures in purely photometric surveys with Euclid, WFIRST, JWST or ELT are
also discussed. While spectroscopy is preferable towards the end of
reionization to provide a robust sample of bubble members, multiband imaging
may be a competitive option for bubbles at z~10, due to the very small number
of line-of-sight interlopers expected at similar redshifts.
