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Stellar Population of the Decoupled Nucleus in M31

Published online by Cambridge University Press:  25 May 2016

O.K. Sil'chenko
Affiliation:
Sternberg Astronomical Institute, Moscow, 119899 Russia Isaac Newton Institute, Chile, Moscow Branch
A. N. Burenkov
Affiliation:
Special Astrophysical Observatory, Nizhnij Arkhyz, 357147 Russia
V. V. Vlasyuk
Affiliation:
Special Astrophysical Observatory, Nizhnij Arkhyz, 357147 Russia

Abstract

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Spectral and imaging results for the central region of M31 are presented. An analysis of absorption-index radial profiles involving Mg, Fe, and Ca lines reveals that the unresolved core of M31 is distinct from the inner bulge in having a higher metallicity; of the two nuclei of M31, it is the fainter in visible light and is located exactly in the dynamical center of the galaxy (and dynamically decoupled) which is chemically distinct. By including the Balmer absorption line Hβ in the analysis, we have disentangled metallicity and age effects; a stellar age difference by a factor of three is found between the nucleus and the bulge, the nucleus being younger. A morphological analysis of CCD images has shown the presence of an inner stellar-gaseous disk with a radius of some 80 pc which is embedded into the bulge.

Type
Part 2: The Database
Copyright
Copyright © Astronomical Society of the Pacific 1999 

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