Research Fellow Studies Star Power of Galaxies

Astronomer Paul Sell finds bursts of forming stars eject gas at very high speeds.

A postdoctoral research fellow at Texas Tech University recently led an effort exploring the evolution of galaxies and why some evolve from ones full of life to passive, star graveyards.

One of the questions that has intrigued astronomers for decades is how galaxies go from forming hundreds of stars each year to none so quickly (if tens of millions of years can be considered quickly). Studying a small set of 12 rare galaxies using the unique capabilities of the Hubble Space Telescope and Chandra X-ray Observatory has provided new insight into how this works in some extreme cases.

Potentially powerful, monstrous black holes at the centers of galaxies are commonly considered responsible for heating up and expelling gas needed to form stars. Paul Sell, along with a group of other researchers, discovered evidence that black holes have less importance than the stars themselves in these extreme cases where formation of new stars is quickly halted.

The most important stars are the heaviest ones with violent, short lives. They burn through their fuel so fast they have a hard time remaining stable and release increasingly powerful winds as they age. Eventually, they collapse when the fuel is used up, resulting in the catastrophic explosion of the star, called a supernova. The combined power from the winds and supernovae of these stars heats up the gas and expels it from the galaxy.