In the Atacama

Findings from Chile offer a glimpse into origins of the universe

Chilean scientists lead discovery of the largest known galaxy cluster, “El Gordo”, literally shedding light on the Big Bang as well as the mysterious dark matter.

Friday, January 13, 2012 Category: Education - Technology
What two galaxy clusters colliding into one another at several million miles per hour looks like (Ph What two galaxy clusters colliding into one another at several million miles per hour looks like (Photo courtesy of ESO/SOAR/NASA).

A team of scientists, led by Chilean and U.S. astronomers, chose this Tuesday’s 219th meeting of the American Astronomical Society to release the latest findings from the Atacama desert’s observatories.


Using the European Southern Observatory’s (ESO) Very Large Telescope (VLT), the international team captured footage of an extremely hot and massive galaxy cluster - the largest ever to have been found in the distant universe.


Dubbed “El Gordo”, “the fattie” in Spanish, the cluster was first picked up by the Atacama Cosmology Telescope. NASA's Chandra X-ray Observatory also collaborated in the project.


Because of the time taken for light from the cluster to travel the seven billion light years to Earth, the discovery offers astronomers a glimpse of the universe billions of years ago.


The images display a faint glow which the team says is a remnant of the light emitted from the Big Bang, the cosmic explosion that gave form to the universe some 13.7 billion years ago.


"This cluster is the most massive, the hottest, and gives off the most X-rays of any cluster found so far at this distance or beyond," said Felipe Menanteau of Rutgers University. "We devoted a lot of our observing time to El Gordo, and I'm glad our bet paid off and we found an amazing cluster collision."


X-ray and optical data reveal two "tails" that give El Gordo a distinct comet-like appearance, but which are, in fact, the site of two galaxy clusters running into one another at several million miles per hour.


The galaxy in the center of El Gordo is unusually bright and has an intense blue color, which the team speculates could be the result of merger between the two galaxies at the center of each of the colliding clusters.


Galaxy clusters are the largest objects in the universe held together by gravity. The merging process in which they take form depends largely on the amount of both dark matter and dark energy present in the universe at the time of their origin. For this reason, the scientists say that studying the cluster could shed more light on these mysterious components of the cosmos, which is believed by NASA to account for 95 percent of matter in the universe, but is invisible to telescopes.