Shock-ionization in the Extended Emission-Line Region of 3C~305. The last piece of the (optical) puzzle

Abstract

We present new Gemini spectroscopical data of the Extended Emission-Line Region of 3C~305 radio galaxy in order to achieve the final answer of the long-standing question about the ionizing mechanism. The spectra show strong kinematic disturbances within the most intense line-emitting region. The relative intensities amongst the emission lines agree with the gas being shocked during the interaction of the powerful radio jets with the ambient medium. The emission from the recombination region acts as a very effective cooling mechanism, which is supported by the presence of a neutral outflow. However, the observed intensity is almost an order of magnitude lower than expected in a pure shock model. So auto-ionizing shock models, in low-density and low-abundance regime, are required in order to account for the observed emission within the region. This scenario also supports the hypothesis that the optical emitting gas and the X-ray plasma are in pressure balance.

13 pages, 6 figures. To be published in MNRAS

References in corpus (5)

• The MAPPINGS III Library of Fast Radiative Shock Models
• The nature of the jet-driven outflow in the radio galaxy 3C305
• Extended X-ray emission in radio galaxies: the peculiar case of 3C 305
• A jet-cloud interaction in the 3C 196 environment
• Searching for evidence of jet-cloud interaction in radio galaxies. First results for 3C 381

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• Integral Field Spectroscopy of the circumnuclear region of the Radio Galaxy Pictor A
• The fingerprints of Photoionization and Shock-Ionization in two CSS sources
• First statistical constraints on galactic scale outflows properties traced by their extended Mg II emission with MUSE