Abstract
view Abstract Citations (41) References (47) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopic Gradients in Bright Elliptical Galaxies Davidge, T. J. Abstract Long-slit spectra of eleven bright elliptical galaxies are used to investigate the radial behavior of various atomic and molecular absorption features in these objects. The majority of features weaken with radius, with the Mg_2_ and Na5895 indices showing the strongest gradients. However, the strengths of Hβ and Hα absorption typically remain constant. The rate of change of the Mg_2_ index with log(r), δ Mg_2_/δ log( r), shows a galaxy-to-galaxy dispersion which is larger than expected from experimental uncertainties, indicating that the galaxies in this study have not been selected from a sample in which all systems have identical radial properties. This suggests that there are system-to-system differences in the star formation histories of elliptical galaxies. Moreover, the rates with which most atomic and molecular features change with respect to Mg_2_ in the outer envelopes of these systems appears to be in better agreement with trends defined by globular clusters than galaxy nuclei. Gorgas et al. [MNRAS, 245,217(1990)] reached similar conclusions in their study of early type galaxies. Values of δ Mg_2_/δ log(r) derived in this study are combined with those published in the literature to search for correlations with various galaxy properties. δ Mg_2_/δ log(r) appears to be loosely correlated with the central velocity dispersion, σ_0_ and the dynamical anisotropy parameter, (v/σ)^*^; although both relations are significant at roughly the 95% confidence level, a larger body of observations is required to establish unambiguously the reality of these relations. A significant relation does not exist between δ Mg_2_/δlog (r) and the integrated galaxy brightness M_B_. Publication: The Astronomical Journal Pub Date: May 1992 DOI: 10.1086/116164 Bibcode: 1992AJ....103.1512D Keywords: Absorption Spectra; Astronomical Spectroscopy; Elliptical Galaxies; Abundance; H Lines; Luminosity; Molecular Absorption; Spectral Line Width; Astrophysics; GALAXIES: ELLIPTICAL AND LENTICULA; GALAXIES: KINEMATICS AND DYNAMICS; TECHNIQUES: SPECTROSCOPIC full text sources ADS | data products SIMBAD (28) NED (11)
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