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TL/DR: compact galaxies rotate fast enough that their centripetal acceleration limit for MOND. Therefore it should look Newtonian, therefore You expect to "not
by throwawaymaths 3y ago
TL/DR: compact galaxies rotate fast enough that their centripetal acceleration limit for MOND. Therefore it should look Newtonian, therefore You expect to "not see dark matter" in them.
FTA: Eyeballing/back of the envelope the NGC 1277 data suggests it falls into that category (me: probably a more careful calculation is warranted). Usually galaxies that fit this are dense elliptical; 1277 is ultramassive lenticular, though to be fair lenticular ~elliptical.
- MattPalmer1086 3y agoI don't believe that's entirely accurate (I am not a cosmologist). It says that because of the acceleration, MOND predicts Newtonian motion. It does not say that you expect not to see dark matter, just that dark matter is not needed to explain that motion. However, this is a problem for dark matter theories precisely because we expect galaxies to form in concentrations of dark matter: "The infall of baryons acts to further concentrate the central dark matter. So the nominal expectation is that there should be plenty of dark matter near the centers of galaxies rather than none at all. That’s not what we see here, so nominally NGC 1277 presents more of a challenge for the dark matter paradigm than it does for MOND"
- throwawaymaths 3y agoWe're saying the same thing.