Dipole Anisotropy in Integrated Linearly Polarized Flux Density in NVSS
  Data
  We study the dipole anisotropy in integrated linearly polarization flux
density in NRAO VLA Sky Survey (NVSS). We extract the anisotropy parameters in
the number counts, number counts weighted by polarization observables, i.e.
degree of polarization (p) and polarization flux (P). We also determine the
anisotropy in the degree of polarization per source and polarization flux per
source. We consider data with several different cuts on the flux density,
S>10,20,30,40,50 mJy. For studies with degree of polarization we impose the
additional cut 0.01<p<1. Similarly for polarization flux we impose, 0.5<P<100
mJy. We find a very significant signal of dipole, both in number counts and P
(or p) weighted number counts. For the case of P weighted number counts the
significance ranges from 8 \sigma to 5 \sigma for S>20 mJy to S>50 mJy. The
corresponding direction parameters are found to be stable with the cut on flux
density. The significance is even higher for the case of p weighted number
counts. The observed anisotropy is found to be much larger in comparison to the
CMBR expectations. We find that polarization observables show a much higher
level of anisotropy in comparison to pure number counts or flux weighted number
counts.
