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HEAO 1 observations of 4U1232+07


While performing an analysis of the NRL HEAO 1 observations of the Virgo cluster and 3C273, we detected X-ray emission from a region between these two objects. The most satisfactory explanation is the presence of two weak X-ray sources, for which we have obtained error boxes. One source is likely to be the peculiar galaxy IC3576, suggested by Margon et al.1 as the source 2U1231+07=4U1232+07 (ref. 2). The error box resulting from combining our observations with the 4U data strengthen the X-ray identification with this extremely interesting galaxy. There are numerous possibilities for the other X-ray source, and here we discuss one, the interacting pair of galaxies NGC4410a and NGC4410b (NGC4410a/b).

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Bhavsar, S., Ulmer, M., Cruddace, R. et al. HEAO 1 observations of 4U1232+07. Nature 281, 462–463 (1979).

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