First Chandra observations of galaxies Original Research Article

Chandraʹs unique combination of sub-arcsecond angular resolution and spectral resolution is very well suited to the study of complex X-ray emitting systems, such as galaxies. In this talk, I give an overview of very early results on galaxies, including examples of normal spirals, actively star-forming and interacting galaxies, and E and S0 galaxies. In all cases, we can easily discriminate between the emission from a population of individual X-rays sources, hot ISM components, and nuclear sources, when present. Highlights of these early results include the detection or very stringent limits on the X-ray emission of the very massive nuclear black holes present in bulges and early-type galaxies; the detection of super-luminous (super-Eddington) sources in actively star-forming galaxies, whose counterpart may be intermediate mass black holes (10–100s M⊙); the detection of the debated population of XRBs in E and SO galaxies; and the detection of a whole range of features in the hot ISM of both late and early-type galaxies.