It is claimed that the existence of dark matter has been confirmed by CHANDRA in 2006. See the article:
A DIRECT EMPIRICAL PROOF OF THE EXISTENCE OF DARK MATTER
"We present new weak-lensing observations of 1E 0657#8722;558 (), a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision of two clusters, the dissipationless stellar component and the fluid-like X-rayemitting plasma are spatially segregated. By using both wide-field ground-based images and HST/ACS images of the cluster cores, we create gravitational lensing maps showing that the gravitational potential does not trace the plasma distribution, the dominant baryonic mass component, but rather approximately traces the distribution of galaxies. An 8 significance spatial offset of the center of the total mass from the center of the baryonic mass peaks cannot be explained with an alteration of the gravitational force law and thus proves that the majority of the matter in the system is unseen."
It seems that normal matter has been found in an amount not enough to produce the gravitational lensing effect observed.
How modified theory of gravities are taking such observations into account?
Any comments are welcome.