New data from NASA's Chandra X-Ray Observatory has led to the discovery of a unique galactic ribbon of hot gas trailing behind a galaxy in what looks to be an X-ray tail. The researchers believe that the tail is the result of gas that was torn away from the galaxy as it moved through a cloud of gas and with a length of at least 250,000 light years. The finding marks the largest of its kind ever detected.
The researchers believe that the tail originated from galaxy CGCG254-021 as it flew through the galaxy cluster Zwicky 8338, which is approximately 700 million light years from Earth. The pressure caused by this rapid motion is what they believe caused gas to tear away from the galaxy and manifest as a unique galactic tail, which contains gas that hits temperatures of ten million degrees and is more than twice the diameter of the Milky Way galaxy.
"Since galaxy clusters are so enormous, they play a critical role in understanding how our universe evolves," Gerrit Schellenberger, who led the study, said in a press release. "To understand galaxy clusters we need to understand how their galaxies change with time, and these X-ray tails provide an important element."
In the image, galaxy CGCG254-021 appears to be moving in the southern direction with the X-ray tail closely behind, with a gap between the two that is the largest of its kind ever seen.
"The large separation between the galaxy and the tail might be telling us that the gas has been completely stripped off the galaxy," said Thomas Reiprich, co-author of the study. "In effect, the tail has been cut off from the galaxy."
Using the data, the researchers were able to learn more able the interactions between the galaxies and the cosmic tail by using properties of both. For example, the bright spot on the tail, referred to as its "head," is located in front of the back end of the X-ray emission and possesses what looks to be hints of a bow shock, which shows similar characteristics to a shock wave that was created in front of the bow shock in the CGCG254-021 galaxy.
"This tail is a vivid example of how dynamic galaxy clusters are, as we may be seeing the transformation of a galaxy as it moves through the cluster," Schellenberger said. "Also, the material in the tail includes not only hydrogen but heavier elements and could spawn a new generation of stars trailing behind the galaxy."
The findings were published in the Nov. 2 issue of Astronomy and Astrophysics.
