Issue |
A&A
Volume 695, March 2025
|
|
---|---|---|
Article Number | L23 | |
Number of page(s) | 11 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202553925 | |
Published online | 21 March 2025 |
Letter to the Editor
Photometric versus dynamical stellar masses and their impact on scaling relations in nearby disc galaxies
1
INAF – Padova Astronomical Observatory, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy
2
Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
3
Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Via G. Sansone 1, I-50019 Sesto Fiorentino, Firenze, Italy
4
Leiden Observatory, Leiden University, P.O. Box 9513 2300 RA Leiden, The Netherlands
⋆ Corresponding author; antonino.marasco@inaf.it
Received:
27
January
2025
Accepted:
24
February
2025
The study of scaling relations of disc galaxies and their evolution across cosmic time requires accurate estimates of galaxy stellar masses, M⋆, over broad redshift ranges. While photometric M⋆ estimates (Mphot) 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⋆ estimates (Mdyn), available for nearby galaxies. Here, we compare newly determined, SED-model-based Mphot with previously obtained Mdyn inferred via rotation curve decomposition techniques in a sample of ∼100 nearby galaxies from the SPARC database. We find that the two mass estimates show a systematic agreement at the ∼12% (0.05 dex) level and a ∼55% (0.22 dex) scatter across almost 5 dex in M⋆. Our Mphot estimates correspond to mass-to-light ratios in the 3.6 μm band that increase gradually with 3.6 μm luminosity, as a consequence of the earlier (later) assembly history of high-mass (low-mass) disc galaxies. The choice of using either Mdyn or Mphot 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 μm band. M⋆ estimates based on the assumption that discs are marginally stable lead to the largest scatter in the scaling relations.
Key words: techniques: photometric / galaxies: evolution / galaxies: fundamental parameters / galaxies: kinematics and dynamics / galaxies: photometry / galaxies: stellar content
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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