Astrometric Evidence for a Population of Dislodged AGNs

Valeri V. Makarov, Julien Frouard, Ciprian T. Berghea, Armin Rest, Kenneth C. Chambers, Nicholas Kaiser, Rolf-Peter Kudritzki, Eugene A. Magnier
2017 Astrophysical Journal Letters  
We investigate a sample of 2293 ICRF2 extragalactic radio-loud sources with accurate positions determined by VLBI, mostly active galactic nuclei (AGN) and quasars, which are cross-matched with optical sources in the first Gaia release (Gaia DR1). The distribution of offsets between the VLBI sources and their optical counterparts is strongly non-Gaussian, with powerful wings extending beyond 1 arcsecond. Limiting our analysis to only high-confidence difference detections, we find (and publish) a
more » ... list of 188 objects with normalized variances above 12 and offsets below 1 arcsecond. Pan-STARRS stacked and monochromatic images resolve some of these sources indicating the presence of double sources, confusion sources, or pronounced extended structures. Some 89 high-quality objects, however, do not show any perturbations and appear to be star-like single sources, yet displaced by multiples of the expected error from the radio-loud AGN. We conclude that a fraction of luminous AGN (more than 4%) can be physically dislodged from the optical centers of their parent galaxies.
doi:10.3847/2041-8213/835/2/l30 fatcat:tj244d7l45hs7mmcp4jsukvlri