The Globular Cluster System of the Virgo Giant Elliptical Galaxy NGC 4636: I. Subaru/FOCAS Spectroscopy and Database

Abstract

We present a spectroscopic study of the globular clusters (GCs) in the giant elliptical galaxy NGC 4636 in the Virgo cluster. We selected target GC candidates using the Washington photometry derived from the deep CCD images taken at the KPNO 4m. Then we obtained the spectra of 164 target objects in the field of NGC 4636 using the Multi-Object Spectroscopy (MOS) mode of Faint Object Camera and Spectrograph (FOCAS) on the SUBARU 8.2m Telescope. We have measured the velocities for 122 objects: 105 GCs in NGC 4636, the nucleus of NGC 4636, 11 foreground stars, 2 background galaxies, and 3 probable intracluster GCs in the Virgo cluster. The GCs in NGC 4636 are located in the projected galactocentric radius within 10arcmin (corresponding to 43 kpc). The measured velocities for the GCs range from 300km/s to 1600km/s, with a mean value of 932_{-22}^{+25} km/s, which is in good agreement with the velocity for the nucleus of NGC 4636, 928\pm 45 km/s. The velocity dispersion of the GCs in NGC 4636 is derived to be 231_{-17}^{+15} km/s and the velocity dispersion of the blue GCs is slightly larger than that of the red GCs. Combining our results with data in the literature, we produce a master catalog of radial velocities for 238 GCs in NGC 4636. The velocity dispersion of the GCs in the master catalog is found to be 225_{-9}^{+12} km/s for the entire sample, 251_{-12}^{+18} km/s for 108 blue GCs, and 205_{-13}^{+11} km/s for 130 red GCs.

27 pages, 9 figues, Accepted by ApJ

References in corpus (9)

• The Kinematics and Dynamics of the Globular Clusters and the Planetary Nebulae of NGC 5128
• The dark matter halo of NGC 1399 - CDM or MOND?
• The Globular Cluster System of M60 (NGC 4649). II. Kinematics of the Globular Cluster System
• The Globular Cluster Kinematics and Galaxy Dark Matter Content of NGC 4649 (M60)
• Dynamics of the NGC 4636 Globular Cluster System - An extremely dark matter dominated galaxy?
• Gemini/GMOS Spectra of Globular Clusters in the Virgo Giant Elliptical NGC 4649
• The Globular Cluster System of M60 (NGC 4649). I. CFHT MOS Spectroscopy and Database
• The Distribution of Dark Matter in the Halo of the early-type galaxy NGC 4636
• Chandra Observations of the X-ray Point Source Population in NGC 4636

Cited by in corpus (10)

• Wide-Field Precision Kinematics of the M87 Globular Cluster System
• The Globular Cluster System of the Virgo Giant Elliptical Galaxy NGC 4636: II. Kinematics of the Globular Cluster System
• Dynamics of the NGC 4636 globular cluster system II. Improved constraints from a large sample of globular cluster velocities
• The Globular Cluster Kinematics and Galaxy Dark Matter Content of NGC 3923
• Isolated ellipticals and their globular cluster systems I: Washington photometry of NGC 3585 and NGC 5812
• The Globular Cluster System of NGC 4636 and Formation of Globular Clusters in Giant Elliptical Galaxies
• SUBARU Spectroscopy of the Globular Clusters in the Virgo Giant Elliptical Galaxy M86
• Mass-Velocity Dispersion Relation in HIFLUGCS Galaxy Clusters
• Gemini/GMOS Spectroscopy of Globular Clusters in the Merger Remnant Galaxy M85
• Stellar kinematics and populations out to 1.5 effective radius in the elliptical galaxy NGC4636