I am writing a research review on dark matter and cosmology. I ran into a paper http://arxiv.org/abs/1104.0539 describing the problems faced by LCDM cosmology. One such problem related to the alignment of the low multipoles of the CMBR (as L. Perivolaropoulos puts it).
The exact phrase used in the paper is
I am comfortable with the idea of octopoles and quadrupoles as higher order terms of the same multipole expansion that gives the dipole fields, but I do not understand what is meant by the plane of the quadrupole and octopole.
Can anybody help me to understand this?
Thanks
cohen990
