An accurate measurement of the baryonic Tully-Fisher relation with heavily gas-dominated ALFALFA galaxies

Understand

We use a sample of 97 galaxies selected from the ALFALFA 21cm survey to make an accurate measurement of the baryonic Tully-Fisher relation (BTFR).

• These galaxies are specifically selected to be heavily gas-dominated (Mgas/M* >~ 2.7) and to be oriented edge-on.
• The former property ensures that the error on the galactic baryonic mass is small, despite the large systematic uncertainty involved in galactic stellar mass estimates.
• The latter property means that rotational velocities can be derived directly from the width of the 21cm emission line, without any need for inclination corrections.