We present the results of determinations of age, helium abundance (Y), metallicity ([Fe/H]), and estimations of abundances of the elements: C, N, O, Mg, Ca, Ti, Cr, Ni, Sr, and Ba of four globular clusters in the neighborhood of the Andromeda galaxy ([SD2009]GC7,Mayall II, Mackey-GC1 (MGC1), and Bol 298 (MGC6)) and of six Galactic clusters. Medium-resolution long-slit integrated-light spectra from the clusters under study were used to determine the parameters.Observations of extra-galactic objects were carried out with the 6-m SAO RAS telescope using the SCORPIO-1 multimode focal reducer. Galactic globular clusters NGC6341 (M92), NGC6838 (M71), and NGC7078 were observed with the CARELEC spectrograph at the 1.93-m telescope of the Haute-Provence Observatory. The integratedlight spectra of Galactic globular clusters NGC104, NGC6121 (M4), and NGC7078 (M15) were taken from the spectral library by Schiavon.We selected the best isochrone for each cluster by comparison of the shapes and intensities of the observed and theoretical Balmer line profiles.

We used integrated-light medium-resolution spectra of six Galactic globular clusters and model stellar atmospheres to carry out population synthesis and to derive chemical composition and age of the clusters. We used medium-resolution spectra of globular clusters published by Schiavon et al. (2005), as well as our long-slit observations with the 1.93 m telescope of the Haute Provence Observatory. The observed spectra were fitted to the theoretical ones interactively. As an initial approach, we used masses, radii and log g of stars in the clusters corresponding to the best fitting isochrones in the observed color-magnitude diagrams. The computed synthetic blanketed spectra of stars were summed according to the Chabrier mass function. To improve the determination of age and helium content, the shape and depth of the Balmer absorption lines was analysed. The abundances of Mg, Ca, C and several other elements were derived. A reasonable agreement with the literature data both in chemical composition and in age of the clusters is found. Our method might be useful for the development of stellar population models and for a better understanding of extragalactic star clusters.

Long-slit medium-resolution spectra of the Galactic globular clusters (GCs) NGC 6229 and NGC 6779, obtained with the CARELEC spectrograph at the 1.93-m telescope of the Haute-Provence observatory, have been used to determine the age, helium abundance (Y), and metallicity [Fe/H] as well as the first estimate of the abundances of C, N, O, Mg, Ca, Ti, and Cr for these objects. We solved this task by comparing the observed spectra and the integrated synthetic spectra, calculated with the use of the stellar atmosphere models with the parameters preset for the stars from these clusters. The model mass estimates, T eff, and log g were derived by comparing the observed “color-magnitude” diagrams and the theoretical isochrones. The summing-up of the synthetic blanketed stellar spectra was conducted according to the Chabrier mass function. To test the accuracy of the results, we estimated the chemical abundances, [Fe/H], log t, and Y for the NGC 5904 and NGC 6254 clusters, which, according to the literature, are considered to be the closest analogues of the two GCs of our study. Using the medium-resolution spectra from the library of Schiavon et al., we obtained for these two clusters a satisfactory agreement with the reported estimates for all the parameters within the errors. We derived the following cluster parameters. NGC 6229: [Fe/H] = -1.65 dex, t = 12.6 Gyr, Y = 0.26, [a/Fe] = 0.28 dex; NGC 6779: [Fe/H] = -1.9 dex, t = 12.6 Gyr, Y = 0.23, [a/Fe] = 0.08 dex; NGC 5904: [Fe/H] = -1.6 dex, t = 12.6 Gyr, Y = 0.30, [a/Fe] = 0.35 dex; NGC 6254: [Fe/H] = -1.52 dex, t = 11.2 Gyr, Y = 0.30, [a/Fe] = 0.025 dex. The value [a/Fe] denotes the average of the Ca and Mg abundances.

Long-slit medium-resolution spectra of the Galactic globular clusters (GCs) NGC6229 and NGC6779, obtained with the CARELEC spectrograph at the 1.93-m telescope of the Haute-Provence observatory, have been used to determine the age, helium abundance (Y), and metallicity [Fe/H] as well as the first estimate of the abundances of C, N, O, Mg, Ca, Ti, and Cr for these objects. We solved this task by comparing the observed spectra and the integrated synthetic spectra, calculated with the use of the stellar atmosphere models with the parameters preset for the stars from these clusters. The model mass estimates, T eff, and log g were derived by comparing the observed “color-magnitude” diagrams and the theoretical isochrones. The summing-up of the synthetic blanketed stellar spectra was conducted according to the Chabrier mass function. To test the accuracy of the results, we estimated the chemical abundances, [Fe/H], log t, and Y for the NGC5904 and NGC6254 clusters, which, according to the literature, are considered to be the closest analogues of the two GCs of our study. Using the medium-resolution spectra from the library of Schiavon et al., we obtained for these two clusters a satisfactory agreement with the reported estimates for all the parameters within the errors. We derived the following cluster parameters. NGC6229: [Fe/H] = −1.65 dex, t = 12.6 Gyr, Y = 0.26, [α/Fe] = 0.28 dex; NGC6779: [Fe/H] = −1.9 dex, t = 12.6 Gyr, Y = 0.23, [α/Fe] = 0.08 dex; NGC5904: [Fe/H] = −1.6 dex, t = 12.6 Gyr, Y = 0.30, [α/Fe] = 0.35 dex; NGC6254: [Fe/H] = −1.52 dex, t = 11.2 Gyr, Y = 0.30, [α/Fe] = 0.025 dex. The value [α/Fe] denotes the average of the Ca and Mg abundances.