Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-02-10
Mon.Not.Roy.Astron.Soc.385:274,2008
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
Scientific paper
10.1111/j.1365-2966.2007.12785.x
We have examined the statistics of the polarization position angles determined for point sources in the NRAO-VLA sky survey (NVSS) and find that there is a statistically significant bias toward angles which are multiples of 45 degrees. The formal probability that the polarization angles are drawn from a uniform distribution is exponentially small. When the sample of those NVSS sources with polarizations detected with a signal to noise $\geq$3 is split either around the median polarized flux density or the median fractional polarization, the effect appears to be stronger for the more highly polarized sources. Regions containing strong sources and regions at low galactic latitudes are not responsible for the non-uniform distribution of position angles. We identify CLEAN bias as the probable cause of the dominant effect, coupled with small multiplicative and additive offsets on each of the Stokes parameters. Our findings have implications for the extraction of science, such as information concerning galactic magnetic fields, from large scale polarization surveys.
Battye Richard A.
Browne I. W. A.
Jackson Neal
No associations
LandOfFree
Biases in the polarization position angles in the NVSS point source catalogue 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 Biases in the polarization position angles in the NVSS point source catalogue, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Biases in the polarization position angles in the NVSS point source catalogue will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-19849