The Small Scatter of the Baryonic Tully–fisher Relation
Dec 14, 20156 pages
Published in:
- Astrophys.J.Lett. 816 (2016) 1, L14
- Published: Dec 31, 2015
e-Print:
- 1512.04543 [astro-ph.GA]
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Abstract: (IOP)
In a Λ cold dark matter (ΛCDM) cosmology, the baryonic Tully–Fisher relation (BTFR) is expected to show significant intrinsic scatter resulting from the mass–concentration relation of dark matter halos and the baryonic-to-halo mass ratio. We study the BTFR using a sample of 118 disk galaxies (spirals and irregulars) with data of the highest quality: extended 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 () is nearly constant at 3.6 μm, we find that the scatter, slope, and normalization of the BTFR systematically vary with the adopted . The observed scatter is minimized for , corresponding to nearly maximal disks in high-surface-brightness galaxies and BTFR slopes close to ∼4. For any reasonable value of , the intrinsic scatter is ∼0.1 dex, below general ΛCDM 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 ΛCDM cosmology.Note:
- 6 pages, 2 figures, accepted for publication in ApJL
- dark matter
- galaxies: evolution
- galaxies: formation
- galaxies: irregular
- galaxies: kinematics and dynamics
- galaxies: spiral
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