Wide-field kinematics of globular clusters in the Leo I group

Free access article

Issue		A&A Volume 448, Number 1, March II 2006


Page(s)		155 - 164
Section		Extragalactic astronomy
DOI		http://dx.doi.org/10.1051/0004-6361:20053697

A&A 448, 155-164 (2006)
DOI: 10.1051/0004-6361:20053697

Wide-field kinematics of globular clusters in the Leo I group

G. Bergond^{1, 2, 3}, S. E. Zepf¹, A. J. Romanowsky^{4, 5}, R. M. Sharples⁶ and K. L. Rhode^{7, 8}

¹ Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
    e-mail: gilles@iaa.es;zepf@pa.msu.edu
² Instituto de Astrofísica de Andalucía, C/ Camino Bajo de Huétor 50, 18008 Granada, Spain
³ GEPI/CAI, Observatoire de Paris, 77 avenue Denfert-Rochereau, 75014 Paris, France
⁴ Departamento de Física, Universidad de Concepción, Casilla 160, Concepción, Chile
    e-mail: romanow@astro-udec.cl
⁵ School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
⁶ Department of Physics, University of Durham, South Road, Durham, DH1 3LE, UK
    e-mail: r.m.sharples@durham.ac.uk
⁷ Department of Astronomy, Wesleyan University, Middletown, CT 06459, USA
    e-mail: kathy@astro.wesleyan.edu
⁸ Department of Astronomy, Yale University, PO Box 208101, New Haven, CT 06520, USA

(Received 24 June 2005 / Accepted 4 November 2005)

Abstract
We present wide-field spectroscopy of globular clusters around the Leo I group galaxies NGC 3379 and NGC 3384 using the FLAMES multi-fibre instrument at the VLT. We obtain accurate radial velocities for 42 globular clusters (GCs) in total, 30 for GCs around the elliptical NGC 3379, eight around the lenticular NGC 3384, and four which may be associated with either galaxy. These data are notable for their large radial range extending from 0 $\farcm$ 7 to 14 $\farcm$ 5 (2 to 42 kpc) from the centre of NGC 3379, and small velocity uncertainties of about 10 km s^-1. We combine our sample of 30 radial velocities for globular clusters around NGC 3379 with 8 additional GC velocities from the literature, and find a projected velocity dispersion of $\sigma_{\rm p} = 175^{+24}_{-22}$ km s^-1 at R < 5' and $\sigma_{\rm p} = 147^{+44}_{-39}$ at R > 5'. These velocity dispersions are consistent with a dark matter halo around NGC 3379 with a concentration in the range expected from a $\Lambda$ CDM cosmological model and a total mass of $\approx\,$ 6 $\,\times\,10^{11} ~M_{\odot}$ . Such a model is also consistent with the stellar velocity dispersion at small radii and the rotation of the $\ion{H}{i}$ ring at large radii, and has a (M/L)_B that increases by a factor of five from several kpc to 100 kpc. Our velocity dispersion for the globular cluster system of NGC 3379 is somewhat higher than that found for the planetary nebulae (PNe) in the inner region covered by the PN data, and we discuss possible reasons for this difference. For NGC 3384, we find the GC system has a rotation signature broadly similar to that seen in other kinematic probes of this SB0 galaxy. This suggests that significant rotation may not be unusual in the GC systems of disc galaxies.

Key words: galaxies: elliptical and lenticular, cD -- galaxies: halos -- galaxies: kinematics and dynamics -- galaxies: star clusters

SIMBAD Objects
Tables at the CDS

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.