The image shown contains X-ray data from Chandra (blue) of the Perseus galaxy cluster, which has been combined with optical data from the Hubble Space Telescope (pink) and radio emission from the Very Large Array (red).
Astronomers re-analysed X-ray data from the Perseus galaxy cluster and their findings may shed light on the nature of the mysterious, invisible dark matter that makes up about 85% of the matter in our Universe.
The Perseus galaxy cluster is one of the most massive nearby clusters. Astrophysicists had previously combined X-ray observations from NASA’s Chandra X-ray satellite, ESA’s XMM-Newton telescope and Hitomi, Japan’s X-ray telescope with optical data from Hubble Space Telescope (HST) and radio emission from the Very Large Array (VLT). All these data had been analysed in an attempt to confirm the existence of a mysterious spike of intensity (emission line) that had been reported at 3.5 keV, but could not been confirmed. If its existence was actually true it could give us important information about the nature of dark matter.
The new analysis suggests that dark matter particles may have two energy states separated by 3.5 keV. If true, it could be possible to observe an absorption line at 3.5 keV when absorbing at angles close to the direction of the black hole and an emission line when looking at the cluster hot gas at large angles away from the black hole.
Scientists will need additional observations of the Perseus and similar clusters, using current and future X-ray telescopes to reveal the nature of the mysterious dark matter.
Publication: Conlon et al. 2017