Big dwarf galaxies steal small ones' stars When two dwarf galaxies meet, the larger one will steal almost all of the smaller galaxy's stars. It had been a mystery how some dwarf galaxies can be so devoid of stars, while remaining full of dark matter. Now computer simulations by Elena D'Onghia of Harvard University and colleagues have shown show that it can happen when a smaller galaxy starts orbiting a larger one.
Starbursts in Dwarf Galaxies Bursts of star making in a galaxy have been compared to a Fourth of July fireworks display: They occur at a fast and furious pace, lighting up a region for a short time before winking out. But these fleeting starbursts are only pieces of the story, astronomers say. An analysis of archival images of small, or dwarf, galaxies taken by NASA's Hubble Space Telescope suggests that starbursts, intense regions of star formation, sweep across the whole galaxy and last 100 times longer than astronomers thought. The longer duration may affect how dwarf galaxies change over time, and therefore may shed light on galaxy evolution.
There is more than one way to make a dwarf galaxy, and NASA's Galaxy Evolution Explorer has found a new recipe. The spacecraft has, for the first time, identified dwarf galaxies forming out of nothing more than pristine gas likely leftover from the early universe. Dwarf galaxies are relatively small collections of stars that often orbit around larger galaxies like our Milky Way.