The 'jet' associated with M89

One of the early successes of the photographic amplification technique was the discovery of the peculiar nature of the Virgo cluster galaxy Messier 89 (NGC 4552). This galaxy looks quite normal on ordinary photographs, but it reveals a faint, very extended feature on deep images such as this.

In the Nature paper where this was announced it was described as a jet, but it is more likely the remains of a dwarf galaxy that M89 has absorbed or disrupted. This paper was also the first to demonstrate the existence of faint 'shells' around elliptical galaxies, but generality of this discovery was not recognised until a little later.

The original, un-enhanced image is inset, to same scale as the main, photograph, which is the result of photographic amplification .
Original plates taken with the UK Schmidt Telescope