The giant elliptical galaxy in the center of this image, taken by NASA's Hubble Space Telescope, is the most massive and brightest member of the galaxy cluster Abell 2261.
Spanning a little more than one million light-years, the galaxy is about 10 times the diameter of our Milky Way galaxy. The bloated galaxy is a member of an unusual class of galaxies with a diffuse core filled with a fog of starlight. Normally, astronomers would expect to see a concentrated peak of light around a central black hole. The Hubble observations revealed that the galaxy's puffy core, measuring about 10,000 light-years, is the largest yet seen.
The observations present a mystery, and studies of this galaxy may provide insight into how black hole behavior may shape the cores of galaxies.
Astronomers used Hubble's Advanced Camera for Surveys and Wide Field Camera 3 to measure the amount of starlight across the galaxy, dubbed A2261-BCG. Abell 2261 is located three billion light-years away.
The observations were taken March to May 2011. The Abell 2261 cluster is part of a multi-wavelength survey called the Cluster Lensing And Supernova survey with Hubble (CLASH).