The position of the nucleus and the nature of the aligned component in 3C 368

被引:32
作者
Stockton, A
Ridgway, SE
Kellogg, M
机构
[1] Institute for Astronomy, University of Hawaii, Honolulu, HI 96822
[2] Physics Department, Oxford University, Oxford OX1 3RH, Keble Road
[3] Astronomy Department, Califonria Inst. of Technol., 105-24, Pasadena
关键词
D O I
10.1086/118063
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present deep spectroscopy and high-resolution IR images of the z = 1.132 radio galaxy 3C 368. The spectroscopy was obtained with LRIS on the Keck I telescope. It shows a complex velocity structure in the emission lines, with brightness enhancements corresponding with excursions of amplitude up to 1500 km s(-1) to higher or lower velocities from a faint, low-velocity ''backbone,'' which may indicate the quiescent outflow pattern. High velocities are correlated with strong emission lines, indicating a connection between the acceleration process and the excitation of the emission. We consider the possibility that the high velocity gas may be due to superwinds from radio-jet-induced starbursts, but we show from energetic considerations that the required mass in young stars is probably inconsistent with the observed continuum. While simple entrainment alone cannot account for the high velocities, it seems almost certain that they arise in some way from the direct interaction of radio jet (or thermal matter entrained in it) with the ambient gas. In the brightest aligned component, we find that about 80% of the UV continuum just beyond the Balmer limit is due to thermal emission from the nebular gas. If previous measurements of greater than or similar to 10% polarization in this region are correct, the true polarization of the residual after removal of the (presumably unpolarized) nebular continuum would be greater than or similar to 50%. However, there are ambiguities in the polarization data and some recent observations show little or no polarization. Finally, our spectroscopy leaves no doubt that Hammer et al. [ApJ, 374, 91 (1991)] have correctly identified what was long supposed to be the nucleus of 3C 368 as a projected Galactic M star. Our IR images show that the true nucleus lies similar to 1.''5 N of the star and is not coincident with any feature prominent in the optical images. (C) 1996 American Astronomical Society.
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页码:902 / 908
页数:7
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