A Generalist, Automated ALFALFA Baryonic Tully-Fisher Relation

TL;DR

This paper develops an inclusive, automated method to derive the Baryonic Tully-Fisher Relation from the ALFALFA galaxy survey, enabling broad application in galaxy evolution and cosmology with improved distance estimates.

Contribution

It introduces a robust, automated approach to measure the BTFR using ALFALFA data, accounting for sample demographics and providing a reliable distance estimation method.

Findings

Best-fit BTFR slope of 3.30±0.06 for the local universe sample.

Distance estimates have an average uncertainty of ~0.17 dex.

Application to Virgo galaxies shows consistent infall signatures.

Abstract

The Baryonic Tully-Fisher Relation (BTFR) has applications in galaxy evolution as a testbed for the galaxy-halo connection and in observational cosmology as a redshift-independent secondary distance indicator. We use the 31,000+ galaxy ALFALFA sample -- which provides redshifts, velocity widths, and HI content for a large number of gas-bearing galaxies in the local universe -- to fit and test an extensive local universe BTFR. This BTFR is designed to be as inclusive of ALFALFA and comparable samples as possible. Velocity widths measured via an automated method and $M_{b}$ proxies extracted from survey data can be uniformly and efficiently measured for other samples, giving this analysis broad applicability. We also investigate the role of sample demographics in determining the best-fit relation. We find that the best-fit relations are changed significantly by changes to the sample mass range and to second order, mass sampling, gas fraction, different stellar mass and velocity width measurements. We use a subset of ALFALFA with demographics that reflect the full sample to measure a robust BTFR slope of $3.30\pm0.06$. We apply this relation and estimate source distances, finding general agreement with flow-model distances as well as average distance uncertainties of $\sim0.17$ dex for the full ALFALFA sample. We demonstrate the utility of these distance estimates by applying them to a sample of sources in the Virgo vicinity, recovering signatures of infall consistent with previous work.