Han-Seek Kim, C. G. Lacey, S. Cole, C. M. Baugh, C. S. Frenk, G. Efstathiou
Star-forming galaxies which are too faint to be detected individually produce
intensity fluctuations in the cosmic background light at infrared,millimetre
and radio wavelengths. This contribution needs to be taken into account as a
foreground when using the primordial signal to constrain cosmological
parameters. The extragalactic fluctuations are also interesting in their own
right as they depend on the star formation history of the Universe and the way
in which this connects with the formation of cosmic structure. We present a new
framework which allows us to predict the occupation of dark matter haloes by
star-forming galaxies and uses this information, in conjunction with an N-body
simulation of structure formation, to predict the power spectrum of intensity
fluctuations in the infrared background. We compute the emission from galaxies
at far-infrared, millimetre and radio wavelengths. Our method gives accurate
predictions for the clustering of galaxies both within and between dark matter
haloes. The calculation presented uses a previously published galaxy formation
model, and, without any adjustment of the model parameters, comes reasonably
close to reproducing recent estimates of the extragalactic fluctuations in the
background made from early data analysed by the Planck Collaboration,
particularly at higher frequencies.
View original:
http://arxiv.org/abs/1111.0721
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