Dark matter even less affected by galactic collisions
DOI: 10.1063/PT.5.028746
BBC : Observations of 72 galactic collisions have revealed to a higher level of detail than ever before that dark matter is unaffected by any force other than gravity. Richard Massey of Durham University in the UK and his colleagues used Hubble Space Telescope and Chandra X-ray Observatory to observe the collisions in both visible and x-ray light. The x-ray images revealed the movement of the clouds of plasma that reside inside and around galaxies whereas the visible images showed the movements of the stars. The combined images allowed the researchers to measure the gravitational lensing effect of the dark matter. The observations revealed that the dark matter exhibited no sign of non-gravitational interactions with itself or other matter to a much higher level of precision than previous observations.
