A new study of the central region of the Perseus galaxy cluster (shown in this image by Nasa’s Chandra X-ray Observatory) and 73 other clusters – imaged with the European Space Agency’s XMM-Newton telescope – has revealed a mysterious X-ray signal in the data. This signal is represented in the circled data points in the inset, which is a plot of X-ray intensity as a function of X-ray energy.
Image Credit: Nasa/European Space Agency
