Document Type
Article
Publication Date
1-4-2016
Abstract
In a Γ cold dark matter (ΓCDM) cosmology, the baryonic TullyFisher relation (BTFR) is expected to show significant intrinsic scatter resulting from the massconcentration relation of dark matter halos and the baryonic-tohalo mass ratio. We study the BTFR using a sample of 118 disk galaxies (spirals and irregulars) with data of the highest quality: extended H I rotation curves (tracing the outer velocity) and Spitzer photometry at 3.6 μm (tracing the stellar mass). Assuming that the stellar mass-to-light ratio (Υ∗) is nearly constant at 3.6 μm, we find that the scatter, slope, and normalization of the BTFR systematically vary with the adopted Υ∗. The observed scatter is minimized for Υ∗ ? 0.5 M⊙/L⊙, corresponding to nearly maximal disks in high-surface-brightness galaxies and BTFR slopes close to ?4. For any reasonable value of Υ∗, the intrinsic scatter is ?0.1 dex, below general ΓCDM expectations. The residuals show no correlations with galaxy structural parameters (radius or surface brightness), contrary to the predictions from some semi-analytic models of galaxy formation. These are fundamental issues for Γ CDM cosmology.
Keywords
dark matter, galaxies: evolution, galaxies: formation, galaxies: irregular, galaxies: kinematics and dynamics, galaxies: spiral
Publication Title
Astrophysical Journal Letters
Rights
© The American Astronomical Society. All rights reserved. This content is free to access, download, and share. For all other uses, you must obtain permission to reuse content: https://journals.aas.org/article-charges-and-copyright/#AAS_material
Recommended Citation
The Small Scatter of the Baryonic Tully-Fisher Relation. Federico Lelli et al 2016 ApJL 816 L14
Manuscript Version
Final Publisher Version