Publication: An interpretation of the line-strength indexes in old stellar populations using an evolutionary synthesis approach
Loading...
Official URL
Full text at PDC
Publication Date
1987-10
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
EDP Sciencies
Citations
Exportar
Abstract
Evolutionary population synthesis models with different metallicities have been computed in order to interpret the observed Mg_2 and Hβ, line-strength indices in old stellar populations. Both indices are found to be quite insensitive to changes in the slope of the IMF and the upper mass limit. These models have been applied to three different cases, with the following results:
a) Galactic globular clusters do not exhibit a significant dispersion in age, and the metallicities of the computed models resemble those estimated for the clusters. The indices for the metal-poor globulars ([Fe/H] < -1) cannot be attained with these models due to the lack of low metallicity evolutionary tracks and stellar spectra libraries.
b) The line-strength gradients observed in the elliptical galaxy NGC 5813 are due, essentially, to intrinsic variations in metallicity, and they cannot be explained just from changes in the remaining parameters of the stellar population.
c) In order to synthesize the M 32 indices we must introduce a star formation elapsed for a long time-scale , the star forrnation being still significant ≈ 5 Gyr ago.
Description
© European Southern Observatory.
© EDP Sciencies.
A. Aragón would like to thank the Basque Government for providing a grant that partially supported him during the elaboration of this work. The authors express their appreciation to Dr. G. Efstathiou for his helpful comments. This work has been partially supported by the Comisión Asesora de Investigación Científica y Técnica (CAICYT No. PB 85-60)
UCM subjects
Unesco subjects
Keywords
Citation
Alcock, C., Paczyński, B.: 1978, Astrophys. J. 223, 224
Arimoto, N., Yoshii, Y.: 1986, Astron. Astrophys. 164, 260
Bruzual, G.: 1983, Astrophys. J. 273, 105
Bruzual, G., Kron, R.G.: 1980, Astrophys. J. 241, 25
Burstein, D.: 1979, Astrophys. J. 232, 74
Burstein, D.: 1985, Publ. Astron. Soc. Pacific 97, 89
Burstein, D., Faber, S.M., Gaskell, C.M., Krumm, N.: 1984, Astrophys. J. 287, 586
Efstathiou, G., Gorgas, J.: 1985, Monthly Notices Roy. Astron. Soc. 215, 37
Faber, S.M.: 1972, Astron Astrophys. 20, 261
Faber, S.M., Frie!, E.D., Burstein, D., Gaskell, C.M.: 1985, Astrophys. J. Suppl. 57, 711
González Riestra, R.: 1986, Ph. D. Thesis, Univ. Complutense, Madrid
Gunn, J.E., Stryker, L.L., Tinsley, B.M.: 1981, Astrophys. J., 249, 48
Jacoby, C.H., Hunter, D.A., Christian, C.A.: 1984, Astrophys. J. Suppl. 56, 257
Maeder, A.: 1981a, Astron. Astrophys. 99, 77
Maeder, A.: 1981b, Astron. Astrophys. 102, 401
Mengel, J.G., Sweigart, A.V., Demarque, P., Gross, P.G.: 1979, Astrophys. J. Suppl. 40, 733
Miller. G.E., Scalo, J.M.: 1979, Astrophys. J. Suppl. 41, 513
Mould, J.R., 1978, Astrophys. J. 220, 434
O'Connell, R.W.: 1976, Astrophys. J. 206, 370
O'Connell, R.W.: 1980, Astrophys. J. 236, 430
Pickles, A.J.: 1985a, Astrophys. J. Suppl. 59, 33
Pickles, A.J.: 1985b, Astrophys. J. 296, 340
Pickles, A.J.: 1987, in "Structure and Dynamics of Elliptical Galaxies'', I.A.U. Symp. 127, D. Reidel, Dordrech, in press
Pritchet, C.: 1977, Astrophys. J. 203, 39
Rose, J.A.: 1985, Astrophys. J. 90, 1927
Spinrad, H., Taylor, B.J.: 1971, Astrophys. J. Suppl. 22, 445
Tinsley, B.M.: 1980, Fund . Cosmic Phys. 5, 287
Tinsley, B.M., Gunn, J.E.: 1976, Astrophys. J. 203, 52
Turnrose, B.E.: 1976, Astrophys. J. 210, 33
VandenBerg, D.A.: 1985, Astrophys. J. Suppl. 58, 711
Williams, T.B.: 1976, Astrophys. J. 209, 716
White, S.D.M.: 1980, Monthly Notices Roy. Astron. Soc. 191, 1
Zinn, R., West, M.J.: 1984, Astrophys. J. Suppl. 55, 45