A. Kashlinsky, R. G. Arendt, M. L. N. Ashby, G. G. Fazio, J. Mather, S. H. Moseley
The distribution on the sky of the luminous objects to form at early times
should be considerably different from the cosmic pattern seen today, with the
differences diverging toward large angular scales and being particularly
prominent between 5' to 1 deg. Although the individual sources at very high z
are too faint to observe on their own, fluctuations in the intensity of the
cosmic infrared background (CIB) will reflect the distribution of those early
objects after foreground sources are removed to sufficiently faint levels.
Previous observations out to scales as large as ~5' had seen the first
indication of excess fluctuations above those expected from ordinary galaxies.
We now extend the measurement of fluctuations to angular scales of ~ 1 deg
using new data obtained in the course of the 2,000+ hour Spitzer Extended Deep
Survey, where we find that the CIB fluctuations continue to diverge to more
than 10 times those of ordinary galaxies. The detected CIB anisotropies are
found to be significantly in excess of random instrument noise and known galaxy
contributions on angular scales out to ~1 deg. The low shot noise levels
remaining in the diffuse maps indicate that the large scale fluctuations arise
from spatial clustering of faint sources well within the confusion noise. The
spatial spectrum of these fluctuations is in reasonable agreement with simple
fitting assuming that they originate in early populations spatially distributed
according to the standard cosmological model (LCDM) at epochs coinciding with
the first stars era. The alternative to this identification would require a new
population never observed before, nor expected on theoretical grounds, but if
true this would represent an important discovery in its own right.
View original:
http://arxiv.org/abs/1201.5617
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