Revisiting stellar properties of star-forming galaxies with stellar and nebular spectral modelling
arXiv:2208.14036 · doi:10.1051/0004-6361/202243856
Abstract
Spectral synthesis is a powerful tool for interpreting the physical properties of galaxies by decomposing their spectral energy distributions into the main luminosity contributors (e.g. stellar populations or ionised gas). However, the impact nebular emission has on the inferred properties of star-forming (SF) galaxies has been largely overlooked over the years. The objective of this work is to estimate the relations between stellar properties of SF galaxies from SDSS DR7 by simultaneously fitting the stellar and nebular continua with FADO and comparing them to the results derived using STARLIGHT, a representative of purely stellar population synthesis codes. Differences between codes regarding average mass, mean age and mean metallicity values can go as high as 0.06 dex for the overall population of galaxies and 0.12 dex for SF galaxies (galaxies with EW(H)>3 Å), with the most prominent difference between both codes in the light-weighted mean stellar age. A closer look into the average light- and mass-weighted star formation histories of intensively SF galaxies (EW(H)>75 Å) suggests that STARLIGHT is underestimating the average light-weighted age of intensively SF galaxies by up to 0.17 dex and overestimating the light-weighted metallicity by up to 0.13 dex compared to FADO (or vice versa). The comparison between the average stellar properties of passive, SF and intensively SF galaxy samples also reveals that differences between codes increase with increasing EW(H) and decreasing total stellar mass. This work finds indirect evidence that a purely stellar population synthesis approach negatively impacts the inferred stellar properties of galaxies with relatively high star formation rates. In turn, this can bias interpretations of fundamental relations such as the mass-age or mass-metallicity.
27 pages, 25 figures. Accepted for publication in Astronomy & Astrophysics
References in corpus (20)
- Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
- The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
- The star formation histories of galaxies in the Sloan Digital Sky Survey
- Reconstructing the Subsurface Three-Dimensional Magnetic Structure of A Solar Active Region Using SDO/HMI Observations
- Recovering galaxy star formation and metallicity histories from spectra using VESPA
- Stellar Population gradients in galaxy discs from the CALIFA survey
- A new library of theoretical stellar spectra with scaled-solar and alpha-enhanced mixtures
- Spectral models for solar-scaled and alpha-enhanced stellar populations
- On the importance of using appropriate spectral models to derive physical properties of galaxies at 0.7<z<2.8
- MILES extended: Stellar population synthesis models from the optical to the infrared
- Aperture-free star formation rate of SDSS star-forming galaxies
- The impact of nebular emission on the broadband fluxes of high-redshift galaxies
- To use or not to use synthetic stellar spectra in population synthesis models?
- Simultaneous analysis of SDSS spectra and GALEX photometry with STARLIGHT: Method and early results
- Recovering stellar population parameters via different population models and stellar libraries
- Impact of an AGN featureless continuum on estimation of stellar population properties
- Clues on the history of early-type galaxies from SDSS spectra and GALEX photometry
- Variations of the Initial Mass Function in Semi-Analytical models
- Stellar populations in hosts of giant radio galaxies and their neighbouring galaxies
- Semi-empirical AGN detection threshold in spectral synthesis studies of Lyman-continuum-leaking early-type galaxies