Testing modified Newtonian dynamics with low surface brightness galaxies: Rotation curve fits

We present modified Newtonian dynamics (MOND) fits to 15 rotation curves of low surface brightness (LSB) galaxies. Good fits are readily found, althou gh for a few galaxies minor adjustments to the inclination are needed. Reas onable values for the stellar mass-to-light ratios are found, as well as an approximately constant value for the total (gas and stars) mass-to-light r atio. We show that the LSB galaxies investigated here lie on the one, uniqu e Tully-Fisher relation, as predicted by MOND. The scatter on the Tully-Fis her relation can be completely explained by the observed scatter in the tot al mass-to-light ratio. We address the question of whether MOND can fit any arbitrary rotation curve by constructing a plausible fake model galaxy. Wh ile MOND is unable to fit this hypothetical galaxy, a normal dark-halo fit is readily found, showing that dark matter fits are much less selective in producing fits. The good fits to rotation curves of LSB galaxies support MO ND, especially because these are galaxies with large mass discrepancies dee p in the MOND regime.