+NASA has discovered using the Chandra X-ray observatory a huge could of multimillion-degree gas in a far away galaxy. The phenomenon is likely caused by a collision between a dwarf galaxy and a spiral galaxy. This impact must caused shock wave that generated hot gas with a temperature of about six million degrees.
The gas cloud is located in a galaxy about 60 million light years from Earth. This discovery could explain how galaxy grow through similar collisions. The mass of the entire gas could could is uncertain because it can not be determined from the 2D image, from the Chrandra X-ray.