The Baryonic Tully‐Fisher Relation of Galaxies with Extended Rotation Curves and the Stellar Mass of Rotating Galaxies

I investigate the baryonic Tully-Fisher relation for a sample of galaxies with extended 21 cm rotation curves spanning the range 20 km s -1 ≲ V f ≤ 300 km s -1 . A variety of scalings of the stellar mass-to-light ratio ϒ ⋆ are considered. For each prescription for ϒ ⋆ , I give fits of the form d = V . Presumably, the prescription that comes closest to the correct value will minimize the scatter in the relation. The fit with minimum scatter has = 50 ☉ km -4 s 4 and x = 4. This relation holds over five decades in mass. Galaxy color, stellar fraction, and ϒ ⋆ are correlated with each other and with d , in the sense that more massive galaxies tend to be more evolved. There is a systematic dependence of the degree of maximality of disks on surface brightness. High surface brightness galaxies typically have ϒ ⋆ ~ of the maximum disk value, while low surface brightness galaxies typically attain ~ of this amount.