  During five ROSAT HRI observations in July 1995, a bright X-ray source
(designated 1RXH J132519.8-430312) was detected 2.5' south-west of the nucleus
of NGC 5128 (Centaurus A) at the outer regions of the elliptical galaxy. At
that time it was the brightest point source in the ROSAT HRI field-of-view. All
other ROSAT observations made before and after these observations show no trace
of the source suggesting that this is a highly variable object. Chandra
observations of Cen A made in September 1999 show a source at the ROSAT
position which may be the quiescent counterpart of the transient. It is very
probable that the transient is located in NGC 5128. Given the existence of a
transient source that close to the direction of NGC 5128, all observations (at
least in soft X-rays) of Cen A, with instruments of low spatial resolution,
must take the presence and variability of this object into account.
