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Large scale structure and kinematics of the LMC from a study of long-period variable stars

Published online by Cambridge University Press:  19 July 2016

Shaun M.G. Hughes
Affiliation:
Anglo-Australian Observatory, Coonabarabran, NSW 2357, Australia
Peter R. Wood
Affiliation:
Mount Stromlo & Siding Spring Observatories, ANU, Canberra, Australia
Neill Reid
Affiliation:
California Institute of Technology, Pasadena, CA, U.S.A.

Abstract

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A recently completed study of the kinematics of Long-Period (or red) Variables (LPVs) in the LMC by Hughes et al. (1990) has shown that those with short periods (100 to 225 days) have spheroidal kinematics (high velocity dispersion and low rotational velocity about the LMC). This is the first evidence of the LMC's possessing a spheroidal population. The spheroid is flattened (with axial ratio c/a ˜0.3 to 0.5), and is not much thicker than the intermediate age disk. The velocity distribution of the old LPVs indicates that the mass of the LMC is ˜ 6.2 ± 1.5 × 109M, and that of the spheroid represented by the old LPVs is ˜2 % of the LMC's total mass. If these old LPVs are members of the LMC's disk, then their velocity dispersion implies that they have an age of ˜10 Gyr. The LPVs with intermediate periods (225 to 450 days) are members of the LMC's rotating disk population, with an age ˜4 Gyr derived from their velocity dispersion, and similar to that of the planetary nebulae, CH stars and old cluster populations.

Type
Large-Scale Structure and Kinematics
Copyright
Copyright © Kluwer 1991 

References

Bahcall, J.N., 1986, Ann. Rev. Astron. Astrophys. 24, 577.CrossRefGoogle Scholar
Bahcall, J.N., Tremaine, S., 1981, Ap. J. 244, 805.CrossRefGoogle Scholar
Bessell, M.S., Freeman, K.C., Wood, P.R., 1986, Ap. J. 310, 710.CrossRefGoogle Scholar
Blanco, V.M., McCarthy, M.F., 1983, A. J. 88, 1442.CrossRefGoogle Scholar
Butler, D., DeMarque, P., Smith, H.A., 1982 Ap. J. 257, 592.CrossRefGoogle Scholar
Cohen, R.S., Dame, T.M., Garay, G., Montani, J., Rubio, M., Thaddeus, P., 1988, Ap. J. (Letters) 331, L95.CrossRefGoogle Scholar
da Costa, G.S., 1990, this volume.Google Scholar
Feast, M.W., 1963, M.N.R.A.S. 125, 367.CrossRefGoogle Scholar
Feast, M.W., 1965, Observatory 85, 16.Google Scholar
Feast, M.W., 1973, in Variable Stars in Globular Clusters and Related Systems , ed. Fernie, J.D. (Dordrecht: Reidel), p.131.CrossRefGoogle Scholar
Feast, M.W., 1984, M.N.R.A.S. 211, 51P.CrossRefGoogle Scholar
Feast, M.W., Glass, I.S., Whitelock, P.A., Catchpole, R.M., 1989, M.N.R.A.S. 241, 375.CrossRefGoogle Scholar
Feitzinger, J.V., Isserstedt, J., Schmidt-Kaler, Th., 1977, Astr. Ap. 57, 265.Google Scholar
Freeman, K.C., 1987, Ann. Rev. Astron. Astrophys. 25, 603.CrossRefGoogle Scholar
Freeman, K.C., Illingworth, G., Oemler, A., 1983, Ap. J. 272, 488.CrossRefGoogle Scholar
Frenk, C.S., White, S.D.M., 1982, M.N.R.A.S. 198, 173.CrossRefGoogle Scholar
Frogel, J.A., 1984, P.A.S.P. 96, 856.CrossRefGoogle Scholar
Hartwick, F.D.A., Cowley, A.P., 1988, Ap. J. 334, 135.CrossRefGoogle Scholar
Hartwick, F.D.A., Cowley, A.P., 1990, this volume.Google Scholar
Hughes, S.M.G., 1989, A. J. 97, 1634.CrossRefGoogle Scholar
Hughes, S.M.G., Wood, P.R., 1990, A. J. , 99, 784.CrossRefGoogle Scholar
Hughes, S.M.G., Wood, P.R., Reid, N., 1990, A. J. , submitted.Google Scholar
Jensen, J., Mould, J., Reid, N., 1988, Ap. J. Suppl. 67, 77.CrossRefGoogle Scholar
Kormendy, J., Illingworth, G., 1982, Ap. J. 256, 460.CrossRefGoogle Scholar
Meatheringham, S.J., Dopita, M.A., Ford, H.C., Webster, B.L., 1988 Ap. J. 327, 651.CrossRefGoogle Scholar
Prévot, L., Rousseau, J., Martin, N., 1989, Astr. Ap. 225, 303.Google Scholar
Reid, N., Glass, I.S., Catchpole, R.M., 1988, M.N.R.A.S. 232, 53.CrossRefGoogle Scholar
Rohlfs, A., Kreitschmann, J., Siegman, B.C., Feitzinger, J.V., 1984, Astr. Ap. 137, 343.Google Scholar
Sawyer Hogg, H., 1973, Publs. David Dunlap Obs. 3, No.6.Google Scholar
Schommer, R.A., Olszewski, U.E.W., Suntzeff, N.B., Harris, H.C., 1990, this volume.Google Scholar
Sommer-Larsen, J., Christensen, P.R., 1989, M.N.R.A.S. 239, 441.CrossRefGoogle Scholar
White, S.D.M., 1989, M.N.R.A.S. 237, 51P.CrossRefGoogle Scholar
Wielen, R., 1977, Astr. Ap. 60, 263.Google Scholar
Wood, P.R., 1989, in From Miras to Planetary Nebulae, conference proceedings, Montpelier, September 1989.Google Scholar
Yamashita, Y., 1975, Publ. Astron. Soc. Japan 27, 325.Google Scholar