The stellar population of the decoupled nucleus in M 31
Abstract
The results of a spectroscopic and photometric investigation of the central region of M 31 are presented. An analysis of absorption-index radial profiles involving magnesium, calcium, and iron lines has shown that the unresolved nucleus of M 31 is distinct by its increased metallicity; unexpectedly, among two nuclei of M 31, it is the faintest one located exactly in the dynamical center of the galaxy (and dynamically decoupled) which is chemically distinct. The Balmer absorption line H-beta has been included into the analysis to disentangle metallicity and age effects; an age difference by a factor 3 is detected between stellar populations of the nucleus and of the bulge, the nucleus being younger. The morphological analysis of CCD images has revealed the presence of a nuclear stellar-gaseous disk with a radius of some 100 pc, the gas component of which looks non-stationary, well inside the bulge of M 31.
Cite
@article{arxiv.astro-ph/9805318,
title = {The stellar population of the decoupled nucleus in M 31},
author = {O. K. Sil'chenko and A. N. Burenkov and V. V. Vlasyuk},
journal= {arXiv preprint arXiv:astro-ph/9805318},
year = {2007}
}
Comments
8 pages LATEX and 7 postscript figures, accepted to Astronomy and Astrophysics