Tuesday, July 14, 2009

Cosmic Microwave Background Anomalies

NASA / WMAP Science Team

Large scale alignment anomalies of CMB anisotropies: a new test for residuals applied to WMAP 5yr maps
The paper lists some anomalies of the CMB with respect to the lambda cold dark matter model:
1. There is low correlation (essentially zero) at large angles, not expected.
2. Unlikely alignments of low order multipole moments: the quadrupole and octupole moments with the dipole moment (which is caused by the motion of the earth). AKA "The Axis of Evil".
3. The two hemispheres defined by the plane of the solar system are asymmetric.
4. A Cold Spot in the southern hemisphere.

Dark Matter Astrophysics

Dark Matter Astrophysics preprint
These lectures are intended to provide a brief pedagogical review of dark matter for the newcomer to the subject. We begin with a discussion of the astrophysical evidence for dark matter. The standard weakly-interacting massive particle (WIMP) scenario--the motivation, particle models, and detection techniques--is then reviewed. We provide a brief sampling of some recent variations to the standard WIMP scenario as well as some alternatives (axions and sterile neutrinos). Exercises are provided for the reader.