The Rotating Nuclear Star Cluster in NGC 4244

Anil C. Seth(1,2), Robert D. Blum(3), Nate Bastian(4), Nelson Caldwell(1), Victor P. Debattista(5)

(1) Harvard-Smithsonian Center for Astrophysics, 60 Garden Street Cambridge, MA 02138
(2) Center for Astrophysics Fellow
(3) National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ, 85721
(4) Institute of Astronomy, University of Cambridge
(5) Centre For Astrophysics, University of Central Lancashire, Preston PR1 2HE, UK

Paper: ApJ, November 2008, in press

Weblink: http://xxx.lanl.gov/pdf/0807.3044v1

EPrint Server: 0807.3044

Abstract:

We present observations of the nuclear star cluster in the nearby edge-on spiral galaxy NGC 4244 using the Gemini Near-Infrared Integral Field Spectrograph (NIFS) with laser guide star adaptive optics. From a previous study of edge-on galaxies, this nuclear star cluster was found to be one of a sample of clusters that appear flattened along the plane of their host galaxies disks. Such clusters show evidence for multiple morphological components, with younger/bluer disk components and older/redder spheroidal components. Our new observations of NGC 4244 show clear rotation of 30 km s^-1 within the central 10 pc (0.5'') of the cluster. The central velocity dispersion is found to be 28+/-2 km s^-1. The multiple stellar populations inferred from the optical colors and spectra are seen as variations in the CO line strength in the NIFS spectra. The rotation is clearly detected even in the older, more spheroidal stellar

Preprints available from the authors at aseth@cfa.harvard.edu , or the raw TeX (no figures) if you click here.

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