Skip to content

Ultracompact dwarfs in the Perseus Cluster: UCD formation via tidal stripping

Research output: Contribution to journalArticlepeer-review

  • Dr Samantha Penny
  • Duncan A. Forbes
  • Jay Strader
  • Christopher Usher
  • Jean P. Brodie
  • Aaron J. Romanowsky

We present the results of a Keck/DEIMOS survey of Ultracompact dwarfs (UCDs) in the Perseus Cluster core. We confirm cluster membership for 14 UCDs, with radial velocities ~5300 km s-1. Two of these confirmed that Perseus UCDs have extremely blue colours (B-R < 0.6 mag), reside in star-forming filaments surrounding NGC 1275, and have likely formed as massive star clusters in the last ~100 Myr. We also measure a central velocity dispersion of a third, UCD13 (σ0 = 38 ± 8 km s-1), the most extended UCD in our sample. We determine it to have radius Re = 85 ± 1.1 pc, a dynamical mass of (2.3 ± 0.8) × 108M, and a metallicity [Z/H]= -0.52+0.33-0.29 dex. UCD13 and the cluster's central galaxy, NGC 1275, have a projected separation of 30 kpc and a radial velocity difference of ~20 km s-1. Based on its size, red colour, internal velocity dispersion, dynamical mass, metallicity, and proximity to NGC 1275, we argue that UCD13 is likely the remnant nucleus of a tidally stripped dwarf elliptical (dE), with this progenitor dE having MB ≈ -16 mag and mass ~109M.

Original languageEnglish
Pages (from-to)3808-3816
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Early online date4 Mar 2014
Publication statusPublished - 21 Apr 2014


  • Ultracompact dwarfs in the Perseus Cluster

    Rights statement: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

    Final published version, 722 KB, PDF document

Related information

Relations Get citation (various referencing formats)

ID: 11064944