An international team of researchers have used the W. M. Keck Observatory to confirm the existence of the most diffuse class of galaxies known in the universe. These Ultra Diffuse Galaxies (UDGs) are nearly as wide as our own Milky Way galaxy — about 60,000 light-years — yet harbour only one percent as many stars.
Hitting the jackpot is one thing, but if you hit the jackpot four times in a row you might wonder if the odds were somehow stacked in your favour. A group of astronomers led by Joseph Hennawi of the Max Planck Institute for Astronomy have found themselves in exactly this situation. They discovered the first known quasar quartet: four quasars, each one a rare object in its own right, in close physical proximity to each other.
An international team of astronomers has pushed back the cosmic frontier of galaxy exploration to a time when the universe was only 5 percent of its present age with the discovery of an exceptionally luminous galaxy more than 13 billion light-years from Earth. The galaxy existed so long ago, it appears to be only 100 million years old.
A new study finds that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centres, in the same way that spiral galaxies do. In these very different types of galaxies, stars and dark matter somehow conspire to redistribute themselves to produce this effect, or does modified Newtonian dynamics offer an explanation?
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