INVESTIGADORES
PIATTI Andres Eduardo
artículos
Título:
The Globular Cluster System of the Low-Luminosity Elliptical Galaxy NGC 1427
Autor/es:
FORTE, J.C.; GEISLER, DOUG; OSTROV, P.; PIATTI, ANDRÉS E.; GIEREN, W.
Revista:
ASTRONOMICAL JOURNAL
Referencias:
Año: 2001 vol. 121 p. 1992 - 2002
ISSN:
0004-6256
Resumen:
Washington photometry is presented for a large number of globular
cluster candidates associated with the low-luminosity elliptical galaxy
NGC 1427 in the Fornax cluster. The survey is mostly complete to
T1=23.5 (V~24.0) and includes an areal coverage of about 216
arcmin2, centered near the galaxy. Most previous studies have
failed to detect any evidence of multiple globular cluster populations
in this low-luminosity elliptical, in sharp contrast to the bimodal
globular cluster systems commonly found in giant ellipticals. The lack
of multimodal cluster populations has been used as the basis for
suggesting that the formation mechanisms for low-luminosity and giant
ellipticals are significantly different. Our metallicity-sensitive
C-T1 photometry (the first such study of a low-luminosity
elliptical) reveals a definite bimodal cluster population. The red
globular cluster population appears strongly centrally concentrated and
practically disappears beyond a galactocentric radius of 120". The mean
color of these clusters is similar to that of the inner galaxy halo.
Blue globulars, on the other hand, exhibit a shallower spatial
distribution. These clusters share a small negative C-T1
color gradient with the galaxy halo, although they are, on average, some
0.3 mag bluer at all galactocentric radii. The overall mean cluster
system metallicity is -0.9+/-0.2. The specific globular cluster
frequency SN is 4.5+/-0.8, if a distance modulus
(V0-MV)=31.0 is adopted. Our results demonstrate
that nonunimodal globular cluster populations exist in low-luminosity
ellipticals, as well as in giant ellipticals, and thus that the
formation mechanisms for these galaxies may share some similarities.