The globular cluster system of NGC 4374

¹ Depto. Astronomía y Astrofísica, P. Universidad Católica de Chile, Casilla 306, Santiago 22, Chile e-mail: mgomez@astro.puc.cl
² Grupo de Astronomía, Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción, Chile e-mail: tom@coma.cfm.udec.cl

Corresponding author: M. Gómez, mgomez@astro.puc.cl

Received: 27 February 2003
Accepted: 7 November 2003

Abstract

We study the globular cluster system (GCS) of the giant elliptical NGC 4374 (M 84) in the Virgo cluster using B and R photometry. The colour distribution is bimodal with peaks at and , fitting well to those found in other early-type galaxies. The radial profile of the cluster number density is flatter than the galaxy light. Using the luminosity function we derive a distance modulus of , which within the uncertainty agrees with the distance from surface brightness fluctuations. Blue and red clusters show similar radial concentrations and azimuthal distributions. The total number of clusters is , which together with our distance modulus leads to a specific frequency of . This value is surprisingly low for a giant elliptical, but resembles the case of merger remnants like NGC 1316, where the low specific frequency is probably caused by the luminosity contribution of an intermediate-age population. A further common property is the high rate of type Ia supernovae which also may indicate the existence of a younger population. However, unlike in the case of NGC 1316, one cannot find any further evidence that NGC 4374 indeed hosts younger populations. The low specific frequency would also fit to a S0 galaxy seen face-on.