A ROSAT PSPC study of NGC 55

The Position Sensitive Proportional Counter onboard ROSAT imaged the spiral galaxy NGC 55 in X-rays for 18.9 ksec. Twenty-two point-like X-ray sources are detected covering the PSPC field-of-view, of which 7 sources are candidate members of NGC 55. The spectra of the brightest sources that are nearest to NGC 55 are consistent either with a heavily absorbed source or a foreground star. The absorbed sources are very likely members of NGC 55. None of the brightest sources appear to be variable in a periodic fashion. Weak diffuse emission is detected in the plane of the galaxy, but only in the energy bands above similar to 0.5 keV. This emission is either the tail of a hot component of the ISM or the emission of unresolved point sources. We argue that the emission is a hot ISM component. A hot plume, visible in the 0.75 keV band, appears to align with an H I plume detected in a VLA total H I map. The cool H I gas appears to surround the hot gas, so the structure represents a chimney. (C) 1997 American Astronomical Society.