The Extended Baryonic Tully-Fisher Relation for SDSS MaNGA Galaxies

TL;DR

This work extends the baryonic Tully-Fisher relation (BTFR) to include both rotation-supported spirals and pressure-supported ellipticals by introducing an effective rotational velocity for ellipticals derived from virial masses. Using 5743 SDSS MaNGA DR17 galaxies and matching to IllustrisTNG 100-1, the authors compute baryonic masses (stars+gas) and total masses, then fit the BTFR with respect to rotational or effective velocities. They find BTFR slopes in the range 3.2–4.0, with a joint MaNGA slope of 3.54^{+0.65}_{-0.48} that agrees with TNG100 for $M_{ m bar} > 10^9 M_\odot$, indicating compatibility with \\LambdaCDM predictions and, within uncertainties, with MOND. The analysis also shows a tighter mass–luminosity relation for ellipticals, validates the methodology against simulations, and emphasizes the need for data at lower baryonic masses to decisively distinguish between competing theories.

Abstract

The baryonic Tully-Fisher relation (BTFR), a relationship between rotational velocity and baryonic mass in spiral galaxies, probes the relative content of baryonic and dark matter in galaxies and thus provides a good test of Lambda CDM. Using H-alpha kinematics to model the rotation curves of spiral galaxies, we construct the BTFR for 5743 SDSS MaNGA DR17 galaxies. To extend the BTFR to higher masses using elliptical galaxies, we estimate their total masses from their stellar velocity dispersions using the virial theorem and define the effective rotational velocity as the velocity a rotation-supported galaxy would exhibit given this mass. The baryonic mass of spiral galaxies is composed of stellar, HI, H2, and He mass, while only the stellar mass is used for the baryonic content of ellipticals. We construct and fit the BTFR for a matched subsample of spiral and elliptical MaNGA and IllustrisTNG 100-1 (TNG100) galaxies, finding BTFR slopes between 3.2 and 4.0. We fit a joint BTFR for the 5743 MaNGA spiral and elliptical galaxies and find a BTFR slope of 3.54 (+0.65/-0.48), which is in good agreement with TNG100 galaxies with baryonic masses greater than 10^9 Msun for which we find a BTFR slope of 3.57 (+0.48/-0.37). Within this mass range, the MaNGA galaxies are consistent with both the Lambda CDM simulation and the prediction from MOND; a sample of lower mass galaxies is necessary to differentiate between the two models.

Figures (16)

• Figure 1: Color-magnitude diagram for the sample of spiral (top) and elliptical (bottom) galaxies. Ravi24. The open red circles are red-sequence galaxies, green stars are green-valley galaxies, and blue crosses are blue-cloud galaxies. The black line separates early- and late-type galaxies.
• Figure 2: Example of stellar mass density map from Pipe3D (top) and best-fit exponential sphere and disk model to this map (bottom). In the bottom figure, the vertical dotted black line corresponds to $R_{90}$ for this galaxy, the dashed black horizontal line shows the stellar mass within $R_{90}$, and the solid horizontal red line shows the total stellar mass of the galaxy.
• Figure 3: Comparison of stellar mass from the NSA and the total stellar mass, $M_*$ determined from the fit to Eq. \ref{['eq:smass']}. The grey dashed line shows where the two masses are equal.
• Figure 4: Top: The ratio of H1 mass to stellar mass as a function of $M_r$ for the MaNGA spirals (blue crosses) and ellipticals (pink x's). The navy triangles (spirals) and red circles (ellipticals) are the means from fits to a Gaussian distribution in bins of $M_r$. The black dashed line shows where the stellar mass equals the H1 mass. Middle: The $M_r$ distribution of all galaxies (open), and those with H1 detections (hatched histogram). Bottom: The fractions of the baryonic mass components as a function of $M_r$.
• Figure 5: Example of the stellar velocity dispersion map from the MaNGA DAP (left), the same map corrected for instrumental effects (center), and the difference between the two (right).