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Evidence against Formation of the Stellar Bulge by Mergers Taking Place over a Hubble Time

Published online by Cambridge University Press:  23 September 2016

R.M. Rich
R.M. Rich*
Affiliation:
Department of Astronomy, Columbia, University, New York, NY 10027

Abstract

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Data on abundances and ages of stars in the nuclear bulge of the Galaxy are in conflict with a scenario in which the bulge has been slowly accumulated by mergers of Magellanic Cloud-like systems taking place over a Hubble Time.

I review the abundance distribution of 88 K Giant stars in Baade's window, and show that the distribution is fit by the simple model of chemical evolution unmodified by gas infall. The metal rich stars in the bulge could not have formed in small galaxies of ≈ 1010 solar masses, which do not retain their metal-enriched gas.

Two large surveys of luminous evolved stars in the bulge–the M giant surveys of Blanco, and the carbon star surveys of Azzopardi, Lequeux, and Rebeirot, find no luminous carbon stars or M supergiants which would signify the presence of an intermediate-age population. I present infrared photometry of 33 bulge carbon stars which shows that they are intrinsically faint, confirming the lack of an intermediate age population.

The lack of young turnoff stars in the color-magnitude diagrams of bulge fields by Terndrup and Rich further strengthens the case against a substantial bulge population younger than 5 Gyr.

Type
The Galactic Bulge
Information
Symposium - International Astronomical Union , Volume 136: The Galactic Center , 1989 , pp. 63 - 69
Copyright
Copyright © Kluwer 1989 

References

Arp, H.C. 1965, Ap.J. , 141, 43.CrossRefGoogle Scholar
Azzopardi, M., Lequeux, J., and Rebeirot, E. 1985, Astron. Astrophys. (Letters) , 145, L4.Google Scholar
Blanco, V.M. and McCarthy, M.F., McCarthy, S.J. 1983, A.J. , 88, 1442.Google Scholar
Blanco, V.M., McCarthy, M.F.S.J., and Blanco, B.M. 1984, A.J. , 89, 636.CrossRefGoogle Scholar
Claussen, M.J., Kleinmann, S.G., Joyce, R.R., and Jura, M. 1987, Ap.J. (Suppl.) , 65, 385.CrossRefGoogle Scholar
Frogel, J.A. and Whitford, A.E. 1987, Ap.J. , 320, 199.Google Scholar
Habing, H.J., Olnon, F.M., Chester, T., Gillett, F., Rowan-Robinson, M., and Neugebauer, G. 1985, Astron. Astrophys. (Letters) , 152, L1.Google Scholar
Hernquist, L. and Quinn, P. 1988 Ap.J. , in press.Google Scholar
Larson, R.B. 1974, M.N.R.A.S. , 166, 585.Google Scholar
Lloyd Evans, T. 1976, M.N.R.A.S. , 174, 169.CrossRefGoogle Scholar
Mould, J.R., 1984, P.A.S.P., 96, 773.CrossRefGoogle Scholar
Mould, J.R., and Aaronson, M., 1986, Ap.J. , 303, 10.CrossRefGoogle Scholar
Rich, R.M. 1985, Mem. S. A. It. , 56, 23.Google Scholar
Rich, R.M. 1988, A.J. , 95, 828.Google Scholar
Rich, R.M., Azzopardi, M., Lequeux, J., and Rebeirot, E. 1987, B.A.A.S. , 19, 1069.Google Scholar
Schweizer, F., and Seitzer, P. 1988, Ap.J. , 328, 88.Google Scholar
Terndrup, D.M. 1988, A.J. , in press.Google Scholar
Tremaine, S.D., Ostriker, J.P., and Spitzer, L. Jr. 1975, Ap.J. , 196, 407.CrossRefGoogle Scholar
Whitford, A.E. 1978, Ap.J. , 226, 777.Google Scholar
Whitford, A.E. 1986, in Spectral Evolution of Galaxies , eds. Chiosi, C. and Renzini, A., (Dordrecht: D. Reidel) p. 157.Google Scholar
Whitford, A.E. and Rich, R.M. 1983, Ap.J. , 274, 723.CrossRefGoogle Scholar
Wood, P.R. and Bessell, M.S. 1983, Ap.J. , 265, 748.CrossRefGoogle Scholar
Yoshii, Y. and Arimoto, N. 1987, Astron. Astrophys , 173, 23.Google Scholar