TITLE:
CMBPol mission concept study: foreground science knowledge and prospects.
AUTHOR(S):
A. A. Fraisse, J.-A. C. Brown, G. Dobler, J. L. Dotson, B. T. Draine, P. C. Frisch, M. Haverkorn, C. M. Hirata, R. Jansson, A. Lazarian, A. M.
Magalhaees, A. Waelkens, M. Wolleben.
DATE:
2008 Nov 24 (arXiv, v1, posted).
AVAILABILITY:
arXiv 0811.3920 (free).
PUBLICATION INFORMATION:
N/A.
ABSTRACT:
Detecting "B-mode" (i.e., divergence free) polarization in the Cosmic Microwave Background (CMB)
would open a new window on the very early Universe. However, the polarized microwave sky is
dominated by polarized Galactic dust and synchrotron emissions, which may hinder our ability to test
inflationary predictions. In this paper, we report on our knowledge of these "Galactic foregrounds," as
well as on how a CMB satellite mission aiming at detecting a primordial B-mode signal ("CMBPol") will
contribute to improving it. We review the observational and analysis techniques used to constrain the
structure of the Galactic magnetic field, whose presence is responsible for the polarization of Galactic
emissions. Although our current understanding of the magnetized interstellar medium is somewhat
limited, dramatic improvements in our knowledge of its properties are expected by the time CMBPol
flies. Thanks to high resolution and high sensitivity instruments observing the whole sky at frequencies
between 30 GHz and 850 GHz, CMBPol will not only improve this picture by observing the synchrotron
emission from our galaxy, but also help constrain dust models. Polarized emission from interstellar dust
indeed dominates over any other signal in CMBPol's highest frequency channels. Observations at these
wavelengths, combined with ground-based studies of starlight polarization, will therefore enable us to
improve our understanding of dust properties and of the mechanism(s) responsible for the alignment
of dust grains with the Galactic magnetic field. CMBPol will also shed new light on observations that
are presently not well understood. Morphological studies of anomalous dust and synchrotron emissions
will indeed constrain their natures and properties, while searching for
fluctuations in the emission from
heliospheric dust will test our understanding of the circumheliospheric interstellar medium. Finally,
acquiring more information on the properties of extra-Galactic sources will be necessary in order to
maximize the cosmological constraints extracted from CMBPol's observations of CMB lensing.
ADS BIBLIOGRAPHIC CODE: N/A.
COMMENTS: N/A.