Analysis of integrated-light spectra of Galactic globular clusters

Abstract

We present the results of determination of the age, helium mass fraction (Y) in terms of the used stellar evolutionary models, metallicity ([Fe/H]), and abundances of the elements C, O, Na, Mg, Ca, Ti, Cr and Mn for 26 globular clusters of the Galaxy. In this work, we apply a method developed by us that employs medium-resolution integrated-light spectra of globular clusters and models of stellar atmospheres and it is supplemented in this paper by the automatic calculation of microturbulence velocities of stars in the studied objects. Based on the data obtained for 26 objects, as well as on the results of our previous studies, it is shown that the abundances of chemical elements, that we measured, with the exception of carbon, are consistent with the literature estimates from the analysis of integrated-light spectra of clusters and from high-resolution spectroscopic observations of their brightest stars. Our estimates of [C/Fe] are consistent with the literature values obtained from the integrated-light spectra of clusters. We interpret the systematic difference between the derived [C/Fe] for globular clusters and the literature [C/Fe] values for the brightest stars of the clusters as a change of the chemical composition in the atmospheres of stars during their evolution. The estimated absolute ages and average Y for the clusters are in a reasonable agreement with the literature data from the analysis of color magnitude diagrams of the objects.

arXiv comment28 pages, 8 figures, 3 tables

References in corpus (46)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Galactic chemical evolution: Carbon through Zinc
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• Properties of stellar generations in Globular Clusters and relations with global parameters
• The Ages of 55 Globular Clusters as Determined Using an Improved delta V_TO^HB Method Along with Color-Magnitude Diagram Constraints, and Their Implications for Broader Issues
• The ACS Survey of Galactic Globular Clusters. IX. Horizontal Branch Morphology and the Second Parameter Phenomenon
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• The formation and assembly history of the Milky Way revealed by its globular cluster population
• The initial mass function : from Salpeter 1955 to 2005
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs I. New atmospheric parameters and masses for 48 stars with planets
• A Comparison of Elemental Abundance Ratios in Globular Clusters, Field Stars, and Dwarf Spheroidal Galaxies
• HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands
• Accurate parameters of 93 solar-type Kepler targets
• Metal-rich, Metal-poor: Updated Stellar Population Models for Old Stellar Systems
• A Library of Integrated Spectra of Galactic Globular Clusters
• An Age Difference of 2 Gyr between a Metal-Rich and a Metal-Poor Globular Cluster
• Globular clusters in the Galactic bulge
• Globular Cluster Abundances from High-Resolution Integrated Light Spectra, I: 47 Tuc
• Detailed abundance analysis from integrated high-dispersion spectroscopy: Globular clusters in the Fornax Dwarf Spheroidal
• The BaSTI Stellar Evolution Database: models for extremely metal-poor and super-metal-rich stellar populations
• SP_Ace: a new code to derive stellar parameters and elemental abundances
• The RAVE catalogue of stellar elemental abundances: first data release
• Constraining stellar population models - I. Age, metallicity, and abundance pattern compilation for Galactic globular clusters
• The origin of stellar populations in the Galactic bulge from chemical abundances
• The age of 47Tuc from self-consistent isochrone fits to colour-magnitude diagrams and the eclipsing member V69
• Spectroscopic Survey of γ Doradus Stars I. Comprehensive atmospheric parameters and abundance analysis of γ Doradus stars
• New insights on the Galactic Bulge Initial Mass Function
• Chemical abundances in bright giants of the globular cluster M62 (NGC 6266)
• The chemical composition of the low-mass Galactic globular cluster NGC 6362
• C${}_{60}^{+}$ - looking for the bucky-ball in interstellar space
• Constraints on the distance moduli, helium and metal abundances, and ages of globular clusters from their RR Lyrae and non-variable horizontal-branch stars. II. Multiple stellar populations in 47Tuc, M3, and M13
• The Age of the Inner Halo Globular Cluster NGC 6652
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. II. Expanding the Metallicity Range for Old Clusters and Updated Analysis Techniques
• Chemical Complexity in the Eu-enhanced Monometallic Globular Cluster NGC 5986
• Detailed abundances from integrated-light spectroscopy: Milky Way globular clusters
• A broad perspective on multiple abundance populations in the globular cluster NGC 1851
• Atmospheric Parameters and Metallicities for 2191 stars in the Globular Cluster M4
• Constant light element abundances suggest that the extended P1 in NGC 2808 is not a consequence of CNO-cycle nucleosynthesis
• Modeling and Analysis of a Spectrum of the Globular Cluster NGC 2419
• Nuclei of dwarf spheroidal galaxies KKs3 and ESO269-66 and their counterparts in our Galaxy
• Gemini spectroscopy of the outer disk star cluster BH176
• Chemical Abundances in the Globular Clusters NGC 6229 and NGC 6779
• A Detailed Study of Giants and Horizontal Branch Stars in M68: Atmospheric Parameters and Chemical Abundances
• Globular Clusters of the Galaxy: Chemical Composition vs Kinematics
• Modeling and analysis of medium-resolution integrated-light spectra of globular clusters in dwarf galaxies

Cited by in corpus (4)

• Investigation of the Prompt SNe Ia progenitor nature through the analysis of the chemical composition of globular clusters and circumgalactic clouds
• Horizontal branch structure, age, and chemical composition for very metal-poor extragalactic globular clusters
• Study of Integrated Spectra of Four Globular Clusters in M31
• Chemical composition and ages of four globular clusters in M31 from the analysis of their integrated-light spectra