UV-extended E-MILES stellar population models: young components in massive early-type galaxies

Abstract

We present UV-extended E-MILES stellar population synthesis models covering the spectral range 1680-50000A at moderately high resolution. We employ the NGSL space-based stellar library to compute spectra of single-age, single-metallicity stellar populations in the wavelength range from 1680 to 3540A. These models represent a significant improvement in resolution and age/metallicity coverage over previous studies based on earlier space-based libraries. These model spectra were joined with those we computed in the visible using MILES, and other empirical libraries for redder wavelengths. The models span the metallicity range -1.79<[M/H]<+0.26 and ages above 30 Myr, for a suite of IMF types with varying slopes. We focus on the behaviour of colours, spectra and line-strength indices in the UV range as a function of relevant stellar population parameters. Whereas some indices strengthen with increasing age and metallicity, as most metallicity indicators in the visible, other indices peak around 3 Gyr for metal-rich stellar populations, such as Mg at 2800A. Our models provide reasonably good fits to the integrated colours and most line-strengths of the stellar clusters of the Milky-Way and LMC. Our full-spectrum fits in the UV range for a representative set of ETGs of varying mass yield age and metallicity estimates in very good agreement with those obtained in the optical range. The comparison of UV colours and line-strengths of massive ETGs with our models reveals the presence of young stellar components, with ages in the range 0.1-0.5 Gyr and mass fractions 0.1-0.5%, on the top of an old stellar population.

31 pages, 31 figures. Published in MNRAS. E-MILES models can be retrieved from http://miles.iac.es/

References in corpus (18)

• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• Population Synthesis in the Blue IV: Accurate Model Predictions for Lick Indices and UBV Colors in Single Stellar Populations
• Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters
• The Great Observatories Origins Deep Survey. VLT/VIMOS Spectroscopy in the GOODS-South Field
• Stellar populations of early-type galaxies in different environments II. Ages and metallicities
• Spectral models for solar-scaled and alpha-enhanced stellar populations
• A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
• A New Catalog of Globular Clusters in the Milky Way
• GALEX UV Color Relations for Nearby Early-Type Galaxies
• An optimized H_βindex for disentangling stellar population ages
• MILES extended: Stellar population synthesis models from the optical to the infrared
• Stellar population synthesis models between 2.5 and 5 μm based on the empirical IRTF stellar library
• Synthetic Mid-UV Spectroscopic Indices of Stars
• Absorption line indices in the UV. Empirical and theoretical stellar population models
• Binary stars and the UVX in early type galaxies
• The innermost globular clusters of M87
• Carbon and Nitrogen Abundances in Early-type Galaxies

Cited by in corpus (22)

• Intracluster Light at the Frontier II: The Frontier Fields Clusters
• The Extended IRTF Spectral Library: Expanded coverage in metallicity, temperature, and surface gravity
• Timing the formation and assembly of early-type galaxies via spatially resolved stellar populations analysis
• The ultra-diffuse galaxy NGC 1052-DF2 with MUSE: II. The population of DF2: stars, clusters and planetary nebulae
• Two new confirmed massive relic galaxies: red nuggets in the present-day Universe
• Stellar atmospheric parameters for 754 spectra from the X-shooter Spectral Library
• The Fornax 3D project: a two-dimensional view of the stellar initial mass function in the massive lenticular galaxy FCC 167
• Comparison of Stellar Population Model Predictions Using Optical and Infrared Spectroscopy
• SDSS-IV MaNGA: Stellar Population Gradients Within Barred Galaxies
• Clocking the assembly of double-barred galaxies with the MUSE TIMER project
• Optical/NIR stellar absorption and emission-line indices from luminous infrared galaxies
• MUSE observations of a changing-look AGN I: The re-appearance of the broad emission lines
• On the formation mechanisms of compact elliptical galaxies
• A metal-poor ultra compact dwarf galaxy at a kiloparsec distance from the low-mass elliptical galaxy FCC47
• Young LMC clusters: the role of red supergiants and multiple stellar populations in their integrated light and CMDs
• Star formation quenching imprinted on the internal structure of naked red nuggets
• The ALHAMBRA survey: 2-D analysis of the stellar populations in massive early-type galaxies at z < 0.3
• Spatially-resolved stellar populations and kinematics with KCWI: probing the assembly history of the massive early-type galaxy NGC 1407
• Unravelling the Origin of the Counter-Rotating Core in IC 1459 with KMOS and MUSE
• Spotting the differences between active and non-active twin galaxies on kpc-scales. A pilot study
• Comparing IMF-sensitive indices of intermediate-mass quiescent galaxies in various environments
• SNITCH: Seeking a simple, informative star formation history inference tool