Evidence for very large-scale coherent orientations of quasar polarization vectors

Details Evidence for very large-scale coherent orientations of quasar polarization vectors Evidence for very large-scale coherent orientations of quasar polarization vectors

Apr 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998a%26a...332..410h&link_type=abstract

Astronomy and Astrophysics, v.332, p.410-428 (1998)

Astronomy and Astrophysics

Astrophysics

52

Large-Scale Structure Of The Universe, Quasars: General, Polarization, Methods: Statistical

Scientific paper

On the basis of a new sample of quasar optical polarization measurements, we have found that, in a region of the sky, the quasar polarization vectors are not randomly oriented as naturally expected, but appear concentrated around one preferential direction. In order to verify this surprising although preliminary result, we have compiled a large sample of quasar polarization measurements from the literature. With quite severe criteria to eliminate at best the contamination by our Galaxy, a sample of 170 quasars with good quality polarization measurements has been defined. Maps in redshift slices reveal a few regions where the polarization vectors are apparently aligned. To handle the problem more quantitatively, non-parametric 3D statistical tests were designed, as well as a method for visualizing spatially the results. The significance is evaluated through Monte-Carlo simulations. Applied to our sample of 170 polarized quasars, two different statistical tests provide evidence, with significance levels of 0.005 and 0.015 respectively, that the optical polarization vectors of quasars are not randomly distributed over the sky but are coherently oriented on very large spatial scales. This orientation effect appears spatially delimited in the 3D Universe, mainly occuring in a few groups of 10-20 objects. The polarization vectors of objects located along the same line of sight but at different redshifts do not appear accordingly aligned. Essentially for this reason, instrumental bias and contamination by interstellar polarization in our Galaxy are unlikely to be responsible for the observed effect. The very large scale at which this local orientation effect is observed indicates the presence of correlations in objects or fields on spatial scales ~ 1000 h(-1) Mpc at redshifts z =~ 1-2, suggesting an effect of cosmological importance. Several possible and testable interpretations are discussed. Tables~2 and 3 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Affiliated with

Also associated with

No associations

Rating

Evidence for very large-scale coherent orientations of quasar polarization vectors does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Evidence for very large-scale coherent orientations of quasar polarization vectors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evidence for very large-scale coherent orientations of quasar polarization vectors will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1601327