Research Note

The nature of faint fuzzies from the kinematics of NGC 1023

¹ University of Nottingham, School of Physics and Astronomy, University Park, NG7 2 RD Nottingham, UK
e-mail: Ana.Chies_Santos@nottingham.ac.uk
² Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo, The Netherlands
³ CSIRO Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, NSW 1710 Epping, Australia

Received: 28 August 2013
Accepted: 16 October 2013

Abstract

Faint fuzzies are metal-rich apparently-old star clusters with unusually large radii (7−15 pc), found mostly in S0 galaxies, whose source remain obscure. To identify their origins, we compare planetary nebulae and neutral hydrogen with faint fuzzy positions and line-of-sight velocities in NGC 1023. In this way, we rule out scenarios in which these objects are associated with an on-going merger or with a spheroid population in NGC 1023. Their kinematics are indistinguishable from the stellar disk population in this galaxy, and we conclude that faint fuzzies are most likely just remnant open clusters. Their observed association with S0s then simply reflects the difficulty of identifying such objects in later-type disk galaxies.