MIGHTEE-HI: The baryonic Tully-Fisher relation over the last billion years

TL;DR

This study analyzes the baryonic Tully-Fisher relation using HI data from 67 galaxies over the last billion years, finding no significant evolution and low scatter similar to local universe measurements.

Contribution

It provides the first detailed measurement of the HI-based baryonic Tully-Fisher relation over a billion-year period with consistent slopes and low scatter, establishing a baseline for future high-redshift studies.

Findings

No evidence of evolution in the bTFr over the last billion years.

Low intrinsic scatter comparable to local universe samples.

Consistent slopes for different rotational velocity measures.

Abstract

Using a sample of 67 galaxies from the MIGHTEE Survey Early Science data we study the HI-based baryonic Tully-Fisher relation (bTFr), covering a period of $\sim$one billion years ($0 \leq z \leq 0.081 $). We consider the bTFr based on two different rotational velocity measures: the width of the global HI profile and $\rm V_{out}$, measured as the outermost rotational velocity from the resolved HI rotation curves. Both relations exhibit very low intrinsic scatter orthogonal to the best-fit relation ($\sigma_{\perp}=0.07\pm0.01$), comparable to the SPARC sample at $z \simeq 0$. The slopes of the relations are similar and consistent with the $ z \simeq 0$ studies ($3.66^{+0.35}_{-0.29}$ for $\rm W_{50}$ and $3.47^{+0.37}_{-0.30}$ for $\rm V_{out}$). We find no evidence that the bTFr has evolved over the last billion years, and all galaxies in our sample are consistent with the same relation independent of redshift and the rotational velocity measure. Our results set up a reference for all future studies of the HI-based bTFr as a function of redshift that will be conducted with the ongoing deep SKA pathfinders surveys.