Figure 25

Figure 25: Examples of MOND fits (blue lines) to two dwarf galaxies [324]. The data for DDO 210 come from [29], and those for UGC 11583 (also known as KK98 250) are from [30] augmented with high resolution data from [281, 242]. The high gas content of these galaxies make them strong tests of MOND, as the one fit-parameter – the mass-to-light ratio of the stars – has only a minor impact on the fit. What is more, as they are deep in the MOND regime, the exact form of the interpolating function (Section 6.2) also has little impact on the fits, making them the cleanest tests of MOND, with essentially no wiggle room. Note that, with a mass of only a few million solar masses (comparable in mass to the largest globular clusters), the Local Group dwarf DDO 210 is the smallest galaxy known to show clear rotation (Vf ∼ 15 km ∕s). It is the lowest point in Figure 3.