What We See at the Collision Site of Two Galaxy Clusters

A few hundred million years ago, two clusters of galaxies crashed into each other, then passed one through the other. This colossal occurrence sent free a barrage of hot gas from each of the clusters, forming an out of the ordinary bridge between the two celestial objects. The said bridge is currently being pounded by particles being pushed away from a supermassive black hole.

Galaxy clusters are the most massive objects in the entire universe being held together by the force of gravity. They hold together hundreds or even thousands of galaxies, astounding quantities of gas that is multi-million-degree temperature that even shines in X-ray light. There even exist huge reserves of dark matter, which cannot be seen.

Abell 2384 is a system that contains enormous structures that can result from the collision of two clusters of galaxies. A gas bridge heated to extremely high temperatures is visible from an overlapping multi-wavelength image. The picture was composed of ESA’s XMM-Newton, with blue light, the Chandra X-ray Observatory, belonging to NASA, and, finally, the Giant Metrewave Radio Telescope with red light, found in India. The technique reveals a jet shooting away from a supermassive black hole, found in the center of a galaxy in one of the clusters. The said jet is so strong that it can change the form of the gas bridge, extending for more than 3 million years, with a mass of about 6 trillion Suns.

One of the versions of the image traces the actual shape of the gas bridge, marking the position and indicating where the jet pushes the hot gas sideways at the site of the crashing. At the actual location of the crashing, scientists discovered a shock front, which is a sonic boom that keeps the gas at a high temperature, not letting it cool down and form new stars.