SIMBAD references

Extended emissions around two active galaxies have been detected with the HRI images of ROSAT in locations where there is no emission present in more sensitive PSPC images. The extended emission in HRI is only present in PHA channels 1 through 3 which implies that it is ultraviolet radiation of predominantly wavelengths 1500 to 1700A. The ultraviolet emission is registered with count rates from 0.7cts/ks for faint filaments, to 2.5cts/ks in associated condensations and bright spots. It would seem necessary to check all HRI observations in order to guard against interpreting signal from this ultraviolet leak as X-rays in the expected 0.1 to 2.4keV band.