Discovery of M87-like ejection in F-71

Abstract

The M87 jet^1,2 is one of the most obvious manifestations of violent activity inside the compact nuclei of galaxies whilst also being one of the most spectacular phenomena of extragalactic astronomy. Although many radio jets are known, very few optical jets have been detected and virtually none is comparable to the prototype jet in M87. Recent charge-coupled device (CCD) images of the southern object F-71 show that this elliptical galaxy (z=0.057) exhibits a brilliant knot ∼14 arc s away from the nucleus and is physically connected to it. Optically, this knot resembles in many respects the bright knots A and B in the M87 jet: its spectrum is featureless and very blue with a slope (α = 1.7±0.1) equal to that of the M87 knots. Its relative luminosity with respect to, and its separation from, the nucleus are both greater than in the M87 galaxy–jet system. We suggest here that the most likely interpretation of the F-71 knot is that it is ejected from the parent galaxy in the same way as the knots in the M87 jet. We propose that further observations of the F-71 system might provide important clues to our understanding of the ejection activity from the nuclei of galaxies.