Looking into the Milky Way’s heart — ISAAC observes the Galactic Centre

The centre of our own galaxy, the Milky Way, is again in the sights of ESO telescopes. This time it’s the turn of ISAAC, the VLT’s near- and mid-infrared spectrometer and camera.

From Chile’s Atacama Desert, site of the ESO observatories, the Milky Way offers magnificent views, particularly in the southern hemisphere winter, when the central region of our galaxy is most visible (see eso0934). However, the Galactic Centre itself, located about 27 000 light-years away in the constellation of Sagittarius, hides behind thick clouds of interstellar dust, which appear as dark obscuring lanes in visible light, but which are transparent at longer wavelengths such as the infrared. In this image, the infrared observations clearly reveal the dense clustering of stars in the galactic core.

ESO telescopes have been tracking stars orbiting the centre of the Milky Way for more than 18 years, getting the highest resolution images of this area and providing a definitive proof of the existence of a supermassive black hole in the heart of our galaxy (read more in eso0226 and eso0846). Infrared flashes emitted by hot gas falling into the supermassive black hole have also been detected with ESO telescopes (see eso0330).

This representative-colour picture is composed of images taken by ISAAC at near-infrared wavelengths through 2.25, 2.09, and 1.71 µm narrowband filters (shown in red, green and blue respectively). It covers a field of view of 2.5 arcminutes.