Model-dependent metallicities of young stellar populations in TIMER galaxies
12 affiliations
- 1Instituto de Astronomia, Geofísica e Ciências Atmosféricas , Universidade de São Paulo, São Paulo, SP ,
- 2Astrophysics Research Institute, Liverpool John Moores University , 146 Brownlow Hill, Liverpool L3 5RF ,
- 3NAT-Universidade Cidade de São Paulo, Rua Galvão Bueno , 868, 01506-000, Sao Paulo, SP ,
- 4Laboratório Nacional de Astrofísica (LNA), Rua dos Estados Unidos 154, Bairro das Nações , 37504-364, Itajubá, MG ,
- 5Durham University Centre for Extragalactic Astronomy, Department of Physics, , South Road, Durham DH1 3LE ,
- 6European Southern Observatory , Alonso de Córdova 3107, Vitacura, Región Metropolitana ,
- 7Universidad de La Laguna , Departamento de Astrofísica, Avenida Astrofiísico Francisco Sánchez s/n, 38205 La Laguna, Tenerife ,
- 8Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n , 38200 La Laguna, Tenerife ,
- 9Universidad Complutense de Madrid Departamento de Física de la Tierra y Astrofísica, , E-28040, Madrid ,
- 10European Southern Observatory , Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen ,
- 11Facultad de Ciencias (Edificio Mecenas), Universidad de Granada Departamento de Física Teórica y del Cosmos, , E-18071 Granada ,
- 12Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada , E-18071 Granada ,
Abstract
Stellar populations in the central regions of disc galaxies provide key constraints on their formation and secular evolution. We investigate the properties of young stellar populations in the centres of nearby barred galaxies from the TIMER survey, using four stellar population models, two based on empirical stellar libraries (MILES, X-Shooter) and two on theoretical libraries (Starburst99, HR-pyPopStar), complemented by independent gas-phase metallicities from emission-line diagnostics. The inferred stellar metallicities depend strongly on the adopted model. Measured as the 5th-to-95th percentile spread across the three galaxies analysed in detail, the empirical libraries recover variations of 1.11 and 0.98 dex, whereas the theoretical ones return 0.40 and 0.49 dex; the gas in the same regions spans 0.49 dex. Gas metallicities are indeed lower in the central star-forming regions, but the amplitude of that depression (about 0.3 dex in NGC 1097) exceeds what bar-driven inflow of disc gas can account for, given typical abundance gradients in literature. The age–metallicity relations consistently reveal two distinct components: an older population consistent with a self-enrichment scenario, and a younger population formed from gas inflows with a different chemical enrichment history. The empirical libraries produce a monotonic decline of metallicities from old to young populations, which would require a sustained inflow of metal-poor gas outpacing its own enrichment. The theoretical libraries instead recover a young component whose metallicity departs from the older populations only at the most recent ages and by a few tenths of a dex, compatible with a single dilution episode. Our results demonstrate that model choice critically affects inferred metallicities, with models based on empirical stellar libraries recovering age–metallicity relations that demand physical conditions the gas measurements cannot sustain.
Related
- Investigating the Young Stellar Populations and Hierarchies in Nearby Galaxies with the UVIT. III. Evidence for a Largest Scale of Correlated Stellar Structures and a Non-universal Fractal Dimension
- Investigating the young stellar populations and hierarchies in nearby galaxies with the UVIT. II. Presenting the properties of ~25,000 UV-detected star-forming clumps
- Physically Motivated Stellar Populations for Galaxies at Cosmic Dawn with a Temperature-Dependent IMF
- The Stellar Populations of Resolved Galaxies
- The Stellar Populations of Two Quiescent Low Surface Brightness Dwarf Galaxies in Low Density Environments
BibTeX
@article{goncalves2026modeldependent,
title = {{Model-dependent metallicities of young stellar populations in TIMER galaxies}},
author = {Geraldo Gonçalves and Paula R T Coelho and Luiz A Silva-Lima and Lucimara Martins and Marie Martig and Dimitri A Gadotti and Camila de Sá-Freitas and Jairo Mendez-Abreu and Patricia Sánchez-Blázquez and Jesús Falcón-Barroso and Glenn van de Venn and Adriana de Lorenzo-Cáceres and Isabel Pérez},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = oct,
doi = {10.1093/mnras/stag1939},
url = {https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag1939/8914598},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Model-dependent metallicities of young stellar populations in TIMER galaxies
AU - Geraldo Gonçalves
AU - Paula R T Coelho
AU - Luiz A Silva-Lima
AU - Lucimara Martins
AU - Marie Martig
AU - Dimitri A Gadotti
AU - Camila de Sá-Freitas
AU - Jairo Mendez-Abreu
AU - Patricia Sánchez-Blázquez
AU - Jesús Falcón-Barroso
AU - Glenn van de Venn
AU - Adriana de Lorenzo-Cáceres
AU - Isabel Pérez
PY - 2026
DA - 2026/10/13
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag1939
UR - https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag1939/8914598
AB - Stellar populations in the central regions of disc galaxies provide key constraints on their formation and secular evolution. We investigate the properties of young stellar populations in the centres of nearby barred galaxies from the TIMER survey, using four stellar population models, two based on empirical stellar libraries (MILES, X-Shooter) and two on theoretical libraries (Starburst99, HR-pyPopStar), complemented by independent gas-phase metallicities from emission-line diagnostics. The inferred stellar metallicities depend strongly on the adopted model. Measured as the 5th-to-95th percentile spread across the three galaxies analysed in detail, the empirical libraries recover variations of 1.11 and 0.98 dex, whereas the theoretical ones return 0.40 and 0.49 dex; the gas in the same regions spans 0.49 dex. Gas metallicities are indeed lower in the central star-forming regions, but the amplitude of that depression (about 0.3 dex in NGC 1097) exceeds what bar-driven inflow of disc gas can account for, given typical abundance gradients in literature. The age–metallicity relations consistently reveal two distinct components: an older population consistent with a self-enrichment scenario, and a younger population formed from gas inflows with a different chemical enrichment history. The empirical libraries produce a monotonic decline of metallicities from old to young populations, which would require a sustained inflow of metal-poor gas outpacing its own enrichment. The theoretical libraries instead recover a young component whose metallicity departs from the older populations only at the most recent ages and by a few tenths of a dex, compatible with a single dilution episode. Our results demonstrate that model choice critically affects inferred metallicities, with models based on empirical stellar libraries recovering age–metallicity relations that demand physical conditions the gas measurements cannot sustain.
SN - 0035-8711
SN - 1365-2966
ER -