Jet-Induced Emission-Line Nebulosity and Star Formation in the High-Redshift Radio Galaxy 4C41.17

Дата и время публикации : 1999-09-14T00:01:24Z

Авторы публикации и институты :
Geoffrey V. Bicknell
Ralph S. Sutherland
Wil J. M. van Breugel
Michael A. Dopita
Arjun Dey
George K. Miley

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Коментарии к статье: 18 pages, 5 figures; uses astrobib.sty and aaspp4.sty. Better versions of figures available via anonymous from
Первичная категория: astro-ph

Все категории : astro-ph

Краткий обзор статьи: The high redshift radio galaxy 4C41.17 consists of a powerful radio source in which previous work has shown that there is strong evidence for jet-induced star formation along the radio axis. We argue that nuclear photoionization is not responsible for the excitation of the emission line clouds and we construct a jet-cloud interaction model to explain the major features revealed by the data. The interaction of a high-powered jet with a dense cloud in the halo of 4C41.17 produces shock-excited emission-line nebulosity through ~1000 km/s shocks and induces star formation. The CIII to CIV line ratio and the CIV luminosity emanating from the shock, imply that the pre-shock density in the line-emitting cloud is high enough (~1-10 cm^-3) that shock initiated star formation could proceed on a timescale of order a few x 10^6 yrs, well within the estimated dynamical age of the radio source. Broad (FWHM ~ 100 – 1400 km/s) emission lines are attributed to the disturbance of the gas cloud by a partial bow–shock and narrow emission lines (FWHM ~ 500 – 650 km/s) (in particular CIV) arise in precursor emission in relatively low metallicity gas. The implied baryonic mass ~ 8 times 10^{10} solar masses of the cloud is high and implies that Milky Way size condensations existed in the environments of forming radio galaxies at a redshift of 3.8. Our interpretation of the data provides a physical basis for the alignment of the radio, emission-line and UV continuum images in some of the highest redshift radio galaxies and the analysis presented here may form a basis for the calculation of densities and cloud masses in other high redshift radio galaxies.

Category: Physics