The large scale effect of the AGN

C. FEINSTEIN

Malargüe, Mendoza

Congreso; 50va Reunión de la Asociación Argentina de Astronomía; 2007

Observatorio PIerre Auger

From the HST/WFPC2 3CR Snapshot Survey, data taken with the filters F555W, F702W and narrow-ramp, a set of galaxies with noticeable extended structure were selected (e.g. 3C 79, 3C 135, 3C 234, etc). All of these objects show large regionsof [O III]$\lambda$\,5007 emission (narrow ramp filter) and the broad-band filters data show similar structures indicating the presence of strong emission in several lines over these regions. The morphology observed seems to be related (e.g. same position angle, direct overlapping or similar shape) with the radio-jet.For some candidates with these properties GMOS/Gemini spectroscopy was taken. These data (both HST direct imaging and Gemini spectroscopy) can be tested with diagnostic diagrams and total UV photons budget to understand the source of energy that is ionizing the gas. This source of ionization was commonly believed to be the UV photons emitted by the powerful AGN, but several of these objects showsclearly that shocks produce by the radio jet are the main cause of the observedgas line emission. We present in this paper the preliminary results of the Gemini/GMOS longslit spectra for four radiogalaxies, these are 3C 135, 3C 180, 3C 234, 3C 284.