Again, they are measuring pure gravity/curvature/mass ONLY.
Mass is by definition the gravitational effect (presumably) 'caused' by matter.
What they failed to understand is if one tries to correlate this mass with any kind of matter one comes up with provably erroneous nonsense.
This is raw gravity without any identifiable 'cause'.
That does not mean there isn't a cause, but it could be external to the observable universe,
and the cause can NOT be is any kind of matter.
'Dark matter' is Provably Wrong. If one thinks about it almost all galaxies behave rotationally differently than one would expect from standard gravity. In the Solar system Mercury orbits every 88 days, while the outer planets take hundreds of Earth years. That entails very different Rotations...
forums.space.com
The universe is not absolutely closed as a system as proved by Godel, because observers of the 'Universe' are a self referencing element of that same 'universe'.
Please get up to speed with the math, guys n gals.