A&A 489, 1065-1071 (2008)
DOI: 10.1051/0004-6361:200810084
Spectroscopy of globular clusters in the low-luminosity spiral galaxy NGC 45
M. D. Mora1, 2, S. S. Larsen3, and M. Kissler-Patig21 Departamento de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso. Av. Gran Bretaña 1111, Valparaíso, Chile
e-mail: mmora@dfa.uv.cl
2 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
e-mail: mkissler@eso.org
3 Astronomical Institute, University of Utrecht, Princetonplein 5, 3584 CC, Utrecht, The Netherlands
e-mail: S.S.Larsen@uu.nl
Received 28 April 2008 / Accepted 24 July 2008
Abstract
Context. Extragalactic globular clusters have been studied in elliptical galaxies
and in a few luminous spiral galaxies, but little is known about
globular clusters in low-luminosity spirals.
Aims. Past observations with the ACS have shown that NGC 45 hosts a large population of globular
clusters (19), as well as several young star clusters. In this work we aim
to confirm the bona fide globular cluster status for 8 of 19 globular cluster candidates and to
derive metallicities, ages, and velocities.
Methods. VLT/FORS2 multislit spectroscopy in combination with the Lick/IDS system was used to derive
velocities and to constrain metallicities and [
/Fe] element ratio of the globular clusters.
Results. We confirm the 8 globular clusters as bona fide globular clusters. Their velocities indicate halo or
bulge-like kinematics, with little or no overall rotation. From absorption
indices such as H
, H
, and H
and the combined [MgFe]' index, we found that
the globular clusters are metal-poor [Z/H]
dex and [
/Fe]
0.0 element ratio.
These results argue in favor of a population of globular clusters formed during the assembling of the galaxy.
Key words: galaxies: individual: NGC 45 -- galaxies: star clusters
© ESO 2008

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