Jet-induced shocks in 3C 171: An intermediate-redshift analog of high-redshift radio galaxies

摘要

We present spectroscopic observations of the extended emission-line region(EELR) aligned with the radio axis of the powerful galaxy 3C 171. The results obtained from a detailed analysis of the observational data show that shocks induced by jet-cloud interactions have a dramatic effect on the extended line-emitting gas. The evidence for shocks includes(1) close radio-optical associations; (2) ion- ization minima coincident with both radio hot spots; (3) high-velocity( ～ 500 km s~-1) line splitting dis- placed by ～ 2" (10 kpc) (a Hubble constant of Ho = 50 km s~-1 and a decleration parameter of q_o are assumed throughout this paper) behind the hot spots on either side of the nucleus, spatially associated with the two inner radio knots: (4) large line widths in the extended gas(FWHM ～1300 km s~-1); and (5) an anticorrelation between line width and ionization state in the extended gas.