Glittering stars. Distorted galaxies. A cluster of more than 100,000 stars. The celestial objects in this six-panel photograph are just a sampling of the more than 300,000 stars and the thousands of distant galaxies seen in the image of a small region of the Andromeda galaxy's halo, a spherical cloud of stars around the galaxy. The image was taken with the Advanced Camera for Surveys aboard NASA's Hubble Space Telescope.
This photograph shows some of the interesting details found in that image. The stars in these panels are located in Andromeda's halo. The galaxies seen in five of the panels represent some of the background galaxies located far beyond Andromeda. A few of them appear distorted, such as the curved red streak of material seen at top row, center. Their distorted shapes suggest that they collided with other galaxies. The white spherical object [bottom row, right] is a collection of more than 100,000 stars called a globular cluster, located in Andromeda's halo. Andromeda is located 2.5 million light-years from Earth.
The members of the M31 halo science team are: T.M. Brown, H.C. Ferguson, E. Smith (STScI); R.A. Kimble, A.V. Sweigart (NASA/GSFC); A. Renzini (ESO); R.M. Rich (UCLA); and D.A. VandenBerg (U. of Victoria)