This question is relevant but it was speaking about a specific discovery reported by pieter van Dokkum, and the answer then mentioned it was disputed whether the paper's conclusion is even correct.
I want to know if there is a galaxy that has been discovered that is completely lacking in dark matter, or as close to lacking in dark matter to such a degree that it it is not certain that it even contains any dark matter at all. because that specific discovery was disputed and I am not sure how to navigate that dispute.
I don't know how scientists "detect dark matter", but based on my googling I think what they do is:
(1) make a mathematical prediction of the mechanics of some of the outer orbiting bodies in a galaxy using the mathematical apparatus of general relativity, and these calcs are based on the observable non-dark matter in the galaxy
(2) instrumentally measuring and recording the positions of those same orbiting bodies and then deducing their mechanics this way.
then comparing the mechanics deduced by the two methods, and depending on the difference in velocities concluded by both methods I guess they would be able to determine the "missing mass" that causes it?
So this question is also "Is there a galaxy in which the mechanics of the outer orbiting bodies' determined by both measurement and general relativity agree with each other perfectly, or almost perfectly?"