Astronomy Picture of the Day

Explanation: Astronomers now report that Chandra X-ray Observatory observations of galaxies known to be frantically forming stars show that these galaxies also contain luminous x-ray sources -- thought to be intermediate mass black holes and immense clouds of superheated gas. Take the lovely island universe NGC 253 for example. At distance of a mere 8 million light-years, NGC 253's prodigious starforming activity has been well studied using high-resolution optical images like the one seen here at lower left. Zooming in on this energetic galaxy's central region, Chandra's x-ray detectors reveal hidden details indicated in the inset at right. In the false-colour image, x-ray hot gas clouds glow near the core and at least four very powerful x-ray sources lie within 3,000 light-years of the centre of the galaxy. Much more luminous than black hole binary star systems in our own galaxy, these extreme x-ray sources may be gravitating toward NGC 253's centre. As a result, NGC 253 and other similar starforming galaxies could ultimately develop a single, central, supermassive black hole, transforming their cores into quasars.