Photometric vs dynamical stellar masses and their impact on scaling relations in nearby disc galaxies

Abstract

The study of scaling relations of disc galaxies and their evolution across cosmic time requires accurate estimates of galaxy stellar masses $M_{\star }$ over broad redshift ranges. While photometric $M_{\star }$ estimates ($M_{\mathrm{phot}}$) based on spectral energy distribution (SED) modelling methods are employed routinely at high-$z$, it is unclear to what extent these are compatible with dynamical $M_{\star }$ estimates ($M_{\mathrm{dyn}}$), available for nearby galaxies. Here we compare newly determined, SED-model based $M_{\mathrm{phot}}$ with previously obtained $M_{\mathrm{dyn}}$ inferred via rotation curve decomposition techniques in a sample of $\sim 100$ nearby galaxies from the SPARC database. We find that the two mass estimates show a systematic agreement at the $\sim 12\%$ ($0.05$ dex) level and a $\sim 55\%$ ($0.22$ dex) scatter across almost $5$ dex in $M_{\star }$. Our $M_{\mathrm{phot}}$ estimates correspond to mass-to-light ratios in the $3.6\mu$m band that increase gradually with $3.6\mu$m luminosity, as a consequence of the earlier (later) assembly history of high-mass (low-mass) disc galaxies. The choice of using either $M_{\mathrm{dyn}}$ or $M_{\mathrm{phot}}$ has only a marginal impact on the slope and zero-point of the Tully-Fisher and Fall relations: the observed orthogonal scatter in both relations is virtually the same for the two methods, and indistinguishable from that derived using a constant mass-to-light ratio in the $3.6\mu$m band. $M_{\star }$ estimates based on the assumption that discs are marginally stable lead to the largest scatter in the scaling relations.

18 pages, 9 figures, 3 Tables. Accepted for publication by A&A

References in corpus (12)

• The GALEX Ultraviolet Atlas of Nearby Galaxies
• SPARC: Mass Models for 175 Disk Galaxies with Spitzer Photometry and Accurate Rotation Curves
• Color--Mass-to-Light Ratio Relations for Disk Galaxies
• From light to baryonic mass: the effect of the stellar mass-to-light ratio on the Baryonic Tully-Fisher relation
• Stellar Populations and the Star Formation Histories of LSB Galaxies: III. Stellar Population Models
• Galactic angular momentum in the IllustrisTNG simulation -- I. Connection to morphology, halo spin, and black hole mass
• A tight angular-momentum plane for disc galaxies
• Stellar Mass-to-light Ratios: Composite Bulge+Disk Models and the Baryonic Tully-Fisher Relation
• The angular momentum of disc galaxies at z=1
• Incorporating baryon-driven contraction of dark matter halos in rotation curve fits
• On the Thermally Pulsing Asymptotic Giant Branch Contribution to the Light of Nearby Disk Galaxies
• A Shallow Slope for the Stellar Mass--Angular Momentum Relation of Star-Forming Galaxies at $1.5<z<2.5$