The active galaxy NGC 4945

K-band image obtained with NACO and the LGS of the active galaxy NGC 4945. The colour-code corresponds to intensity. Lurking in the very heart of this spiral galaxy is a supermassive black hole that is obscured at optical and infrared wavelengths, but which is one of the brightest in the local universe when observed in hard X-rays. The new LGS observations with NACO resolved the continuum in the central thousand light-years into a multitude of individual stars. The exquisite detail meant that it was possible to measure the magnitudes of the brightest of these stars. It suggests that they are red supergiant stars, which would have been born about 10 million years ago. Closer to the nucleus, the stars group into clusters, and become ever more closely packed. The huge luminosity of the central few clusters suggests that there are 10 to 100 such supergiant stars in each of these, packed into regions just a few parsecs across.