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Calibration of metallicity effects on the integrated colors of globular clusters and early-type galaxies

Aaronson, Marc and Cohen, Judith G. and Mould, Jeremy and Malkan, Matthew (1978) Calibration of metallicity effects on the integrated colors of globular clusters and early-type galaxies. Astrophysical Journal, 223 . pp. 824-834. ISSN 0004-637X. doi:10.1086/156315.

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New infrared observations of globular clusters have been obtained which show that both infrared and optical colors are strongly correlated with metallicity and which provide an empirical calibration of abundance effects in composite stellar systems. Models have been constructed, based on the isochrones of Ciardullo and Demarque, with Z-values between 0.0001 and 0.04, and slope of the initial mass function s between 0 and 4. Metal-poor models with s ≤ 2.35 (the Salpeter function) give good agreement with the empirical calibration. Metal-rich models are compared with observations of the central regions of early-type galaxies, and imply that galaxies which have -19 ≥ M_v ≥ -23 correspond to a range in metallicity of 0.0 ≤ [M/H] ≤ +0.3. Models with s = 2.35 adequately fit the observations; proper accounting of metallicity effects on narrow-band infrared features does not require s < 2, as previously published models have suggested. An upper limit on s of 3.2 is determined.

Item Type:Article
Related URLs:
URLURL TypeDescription
Cohen, Judith G.0000-0002-8039-4673
Mould, Jeremy0000-0003-3820-1740
Malkan, Matthew0000-0001-6919-1237
Additional Information:© American Astronomical Society • Provided by the NASA Astrophysics Data System. Received 1977 December 9; accepted 1978 February 8. We thank John Huchra, Bruce Carney, and Phil Marcus for their assistance at the telescope. We also thank Doug Kleinmann, Jay Frogel, Eric Persson, and George Rieke for discussions and encouragement during the course ofthis work. M. A. and M. M. thank the Center for Astrophysics for generous financial support. This research was partially supported with funds from NSF grants AST 76-81874 and AST 76-22991.
Funding AgencyGrant Number
Smithsonian Astrophysical ObservatoryUNSPECIFIED
NSFAST 76-81874
NSFAST 76-22991
Subject Keywords:cluster: globular — galaxies: stellar content — stars: abundances
Record Number:CaltechAUTHORS:20190529-161903769
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95915
Deposited By: George Porter
Deposited On:31 May 2019 14:30
Last Modified:16 Nov 2021 17:16

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