Do Modified Newtonian Dynamics Follow from the Cold Dark Matter Paradigm?

In a recent paper, Kaplinghat & Turner (KT) advertised that modified Newtonian dynamics (MOND) could be derived naturally in the cold dark matter (CDM) paradigm. They actually proceeded to produce a more limited result: Every galaxy should have a transition radius r_t below which baryons dominate and above which dark matter takes over; the acceleration at r_t is nearly the same for all galaxies, and owing to coincidences, this is on the order of a₀ ~ cH₀. This follows from their tacit, intermediate result, whereby CDM halos of galaxies have a very nearly universal acceleration profile, a(r) = v²(r)/r ≈ A(r/l), where A is universal and only the scale l varies from halo to halo. (This remains so when baryons are added because KT assume a universal baryon-collapse factor.) The KT scenario is phenomenologically wrong—observed galaxies are simply not like that. For example, their scenario precludes altogether the existence of low surface brightness galaxies, in which the acceleration is everywhere smaller than a₀. The phenomenologically sound outcome—i.e., the role of a₀ as a transition acceleration in high surface brightness galaxies—pertains to only a small part of the statement of MOND. There are several other independent roles that a₀ ~ cH₀ plays in MOND phenomenology and other predictions of MOND, not related to the value of a₀, that are not explainable in the KT scenario. The results of KT also disagree with those of CDM simulations, which, as they now stand, do not reproduce any aspect of MOND phenomenology.