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Astron. Astrophys. 338, 840-842 (1998)

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1. Introduction

3C287 is a compact steep spectrum (CSS) quasar at a redshift of z=1.055. It was observed from 22.5 to 0.6 GHz with conventional interferometry (van Breugel et al. 1984, 1992) and VLBI technique (Nan et al. 1988, 1991a; Fanti et al. 1985, 1989; Dallacasa et al. 1998). The source does not show any structure with the VLA, its overall extent is less then 100 mas. The observed structure at VLBI scales is complex, indicative of a helical core-jet morphology (Fanti et al. 1989). There is a faint, filamentary halo to the W-SW at 1.6 GHz (Fanti et al. 1985, Nan et al. 1988) which becomes more dominant at 0.6 GHz and extends to E-NE, too (Nan et al. 1991a).

In the class of CSS sources there are some potential precessing candidates reported in earlier works: 3C119 (Fanti et al. 1986; Nan et al. 1991b), 3C287 (Fanti et al. 1989), 3C343 (Sanghera et al. 1997) and 3C380 (Kus et al. 1993). Precessing jets may indicate the presence of double black holes in the the center of these objects (e.g. Hardee et al. 1994 and references therein), though an alternative twisted accretion disk model also exists (Appl et al. 1996). Precession may also occur in merging galaxies, a scenario proposed to explain the complex structure of some CSS sources (van Breugel et al. 1988). In the present paper we show a new 5 GHz VLBI image of 3C287 and discuss its morphology.

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© European Southern Observatory (ESO) 1998

Online publication: September 17, 1998