Weighing Galaxy Disks with the Baryonic Tully-Fisher Relation

Understand

We estimate the stellar masses of disk galaxies with two independent methods: a photometrically self-consistent color$-$mass-to-light ratio relation (CMLR) from population synthesis models, and the Baryonic Tully-Fisher relation (BTFR) calibrated by gas rich galaxies.

• These two methods give consistent results.
• The CMLR correctly converts distinct Tully-Fisher relations in different bands into the same BTFR.
• The BTFR is consistent with $M_b \propto V_f^4$ over nearly six decades in mass, with no hint of a change in slope over that range.