1. High-resolution observations of powerful radio sources Monica Orienti Almudena Prieto 13/12/2007 Monica Orienti – IAC

2. Outline 1.Powerful radio sources 2.Hot-spot 3.Young radio sources

3. 1.Powerful radio sources L 1.4 GHz > 10 24 W/Hz Size: from pc to a few Mpc Elliptical galaxies and quasars; 10% of AGN population 1.04 Mpc

4. Radio morphology Core Jet Hot spot Lobe Hot spot Cygnus A 1. Powerful radio sources

5. The central component B P  E 2 B 2  E 2 B e-e- Synchrotron radiation 1. Powerful radio sources

6. The external component Reacceleration in the hot-spots Electrons are deposited in the lobes where they age: t syn  10 8 years Transient phenomenon Jet Hot-spot Lobe 1. Powerful radio sources

7. Synchrotron radiation B e-e- P  E 2 B 2  E 2 B S   S   0.5 br S br  B -3 t -2

8. 2. Hot-spot S   S   0.5 br S br  B E 2 t syn  br -1/2 B -3/2

9. Sample selection - 9 hot-spots observed with VLA and VLT with high-resolution < 1” - All hot-spots are characterized by: Low magnetic field Low radio power 2. Hot-spot

10. Results 4 hot-spots (  45%) detected 3 hot-spots show extended optical emission 2. Hot-spot

11. The goal What originates the extended features? 2. Hot-spot

12. 3. Young radio sources LLS < 1 kpc; P 1.4 GHz > 10 25 W/Hz; t ~ 10 3 – 5 yr 300 pc

13. The ISM and the source growth Strong flux-density and arm- length asymmetries in compact (< 15 kpc) radio sources 3. Young radio sources

14. The goal How the ambient medium influences the source growth? Evidence of jet-cloud interaction? 3. Young radio sources

15. Seyfert galaxies Usually not powerful in radio Unresolved non-thermal component in the centre High-resolution radio observations to characterize the SED of the central region (A. Prieto, J. Acosta, J.A. Fernandez-Ontiveros)