HAWK-I [1] is one of the newest and most powerful cameras on ESO’s Very Large Telescope (VLT). It is sensitive to infrared light, which means that much of the obscuring dust in the galaxies’ spiral arms becomes transparent to its detectors. Co…
The discovery of a faint trail of stars in the nearby Andromeda galaxy offers new evidence that large spiral galaxies have grown by gobbling up smaller satellite galaxies. Andromeda (also known as M31) is the nearest large galaxy to our own Milky Way and is very similar to it in appearance. Studying Andromeda gives astronomers an external perspective on a galaxy much like our own–it’s like looking at a bigger sibling of our galaxy.
Until now, astronomers haven’t been able to offer a full explanation for why the Milky Way and other galaxies produce new stars at a relative snail’s pace. While they have known for decades that high turbulence keeps huge clouds of hydrogen gas from condensing into stars, they haven’t identified all the causes of the galactic perturbations. In a coming report researchers in San Diego say they have discovered that a well-known, but overlooked source of heating?regular outbursts of ultraviolet radiation from clusters of very large, bright stars?may play a significant role in keeping the Milky Way’s gas continually stirred up.