X-shaped radio sources as the core-dominated triple blazars Andrzej Marecki Centre for Astronomy N. Copernicus University, Toruń, Poland X-shaped radio sources as the parent population of core-dominated triple blazars RTS 2012 Conference Manchester, 18-20.04.2012

X-shaped sources

collision of backflows? The cause of X-shape: collision of backflows? 3C20 3C192

Repositioning of a standard double leading to an X-shaped source

X-shaped sources 3C223 3C403

Core-dominant triples (CDT) from the FIRST survey

Overall structure of J1625+2712 – a CDT with a steep-spectrum core

The „core” of J1625+2712 resolved with the EVN. It appears that the „core” of J1625+2712 is in fact a compact double misaligned w.r.t. the outer lobes. It's a new arm of an X-shaped source.

J1625+2712 – SDSS image Photometry: u=19.02, g=17.41, r=16.76, i=16.52, z=16.39 The redshift is unknown.

Core-dominant triples (CDT) from the FIRST survey

Beaming effects in classical FRII source

X-shaped sources 3C223 3C403

Core-dominant triples with blazar cores 663 kpc (z=0.347) 625 kpc (z=0.715)

Conclusions 1. Our preferred interpretation of the nature X-shaped sources is that they are just standard doubles that have undergone repositioning of the axis. The “wings” are former lobes. 2. At least some core-dominant triples (CDTs) can either be: a) X-shaped sources seen shortly after the repositioning: CDTs with steep-spectrum central component, or: b) “grown-up” X-shaped sources where the “active” arm of the cross is beamed towards the observer: CDTs with flat spectrum central component. 3. X-shaped sources are the parent population of CDTs of large overall sizes (~5 x 105 kpc) and whose central components are identified with blazars.