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The Globular Cluster Terzan 7 in the Sagittarius Dwarf Spheroidal Galaxy

Published online by Cambridge University Press:  03 August 2017

Enrico V. Held
Affiliation:
Osservatorio Astronomico di Padova, I-35122 Padova, Italy
Alfred Rosenberg
Affiliation:
Instituto de Astrofísica de Canarias, 38200 La Laguna, Spain
Ivo Saviane
Affiliation:
European Southern Observatory, Casilla 19001, Santiago 19, Chile
Yazan Momany
Affiliation:
Dipartimento di Astronomia, Univ. di Padova, I-35122 Padova, Italy

Abstract

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We present deep V, I photometry of the globular cluster Terzan 7, a probable member of the globular cluster system of the Sagittarius dwarf spheroidal galaxy. The metallicity, estimated from a new method based on analytic RGB fits, agrees with previous estimates based on color-magnitude diagrams ([Fe/H]= −0.9 ± 0.1 dex). This result confirms a discrepancy between photometric and spectroscopic determinations. Using both the horizontal and vertical methods to estimate relative ages, we confirm that the age of Terzan 7 is about 70% that of 47 Tuc. A rich population of blue stragglers is found, strongly concentrated toward the center of the cluster.

Type
Part 1. The Star Clusters of Local Group Galaxies
Copyright
Copyright © Astronomical Society of the Pacific 2002 

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