http://arxiv.org/abs/1611.02630
We have cross matched the Gaia Data Release 1 secondary dataset that contains positions of 1.14 billion objects against the most complete to date catalogue of VLBI positions of 11.4 thousand sources, almost exclusively active galactic nuclei. We found 6,064 matches, i.e. 53% radio objects. The median uncertainty of VLBI positions is a factor of 4 smaller than the median uncertainties of their optical counterparts. Our analysis shows that the distribution of normalized arc lengths significantly deviates from Rayleighian shape with an excess of objects with small normalized arc lengths and with a number of outliers. We found that 8% matches have radio optical offsets significant at 99% confidence level. Therefore, we conclude there exists a population of objects with genuine offsets between centroids of radio and optical emission.
L. Petrov and Y. Kovalev
Wed, 9 Nov 16
40/56
Comments: 5 pages, 5 figures, 3 tables; submitted to MNRAS Letters; full electronic versions of 2 tables are available from the preprint source
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