Astronomers Discover Most Efficient Star Making Galaxy Ever Observed
Posted on April 24, 2013
Astronomers announced they have found a galaxy turning gas into stars with almost 100% efficiency. The galaxy is named SDSSJ1506+54. The astronomers say this is a rare phase of galaxy evolution and it is the most extreme yet observed. The galaxy is forming stars at a rate hundreds of times faster than the Milky Way. SDSSJ1506+54 is the tiny red dot in the image above. You can see a larger version of the image here.
Jim Geach of McGill University, lead author of a new study appearing here in the Astrophysical Journal Letters, said in a statement, "Galaxies burn gas like a car engine burns fuel. Most galaxies have fairly inefficient engines, meaning they form stars from their stellar fuel tanks far below the maximum theoretical rate. This galaxy is like a highly tuned sports car, converting gas to stars at the most efficient rate thought to be possible."
The findings come from the IRAM Plateau de Bure interferometer in the French Alps, NASA's Wide-field Infrared Survey Explorer and NASA's Hubble Space Telescope. SDSSJ1506+54 jumped out at the researchers when they observed it using data from WISE's all-sky infrared survey. The IRAM Plateau de Bure Interferometer was then used to measure the amount of gas in the galaxy. The IRAM detected millimeter-wave light coming from carbon monoxide, an indicator of the presence of hydrogen gas, which is fuel for stars. Combining the rate of star formation derived with WISE, and the gas mass measured by IRAM, the scientists get a measure of the star formation efficiency.
The astronomers found the galaxy is close to the theoretical maximum, called the Eddington limit. The Eddington limit is the point at which the force of gravity pulling gas together is balanced by the outward pressure from the stars. Above the Eddington limit, the gas clouds are blown apart and star formation is halted.