Compact stellar systems around NGC 1399

P. Firth*, M. J. Drinkwater, E. A. Evstigneeva, M. D. Gregg, A. M. Karick, J. B. Jones, S. Phillipps

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

27 Citations (Scopus)

Abstract

We have obtained spectroscopic redshifts of colour-selected point sources in four wide area VLT-FLAMES ( Very Large Telescope-Fibre Large Array Multi Element Spectrograph) fields around the Fornax cluster giant elliptical galaxy NGC 1399, identifying as cluster members 27 previously unknown faint (-10.5 <M-g' <-8.8) compact stellar systems (CSS), and improving redshift accuracy for 23 previously catalogued CSS.

By amalgamating our results with CSS from previous 2dF observations and excluding CSS dynamically associated with prominent (non-dwarf) galaxies surrounding NGC 1399, we have isolated 80 'unbound' systems that are either part of NGC 1399's globular cluster (GC) system or intracluster GCs. For these unbound systems, we find (i) they are mostly located off the main stellar locus in colour-colour space; (ii) their projected distribution about NGC 1399 is anisotropic, following the Fornax cluster galaxy distribution, and there is weak evidence for group rotation about NGC1399; (iii) their completeness-adjusted radial surface density profile has a slope similar to that of NGC 1399's inner GC system; (iv) their mean heliocentric recessional velocity is between that of NGC 1399' s inner GCs and that of the surrounding dwarf galaxies, but their velocity dispersion is significantly lower; (v) bright CSS (MV <-11) are slightly redder than the fainter systems, suggesting they have higher metallicity; (vi) CSS show no significant trend in g'-i' colour index with radial distance from NGC 1399.

Original languageEnglish
Pages (from-to)1342-1352
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume382
Issue number3
DOIs
Publication statusPublished - 11 Dec 2007

Keywords

  • galaxies : clusters : individual : Fornax cluster
  • galaxies : distances and redshifts
  • galaxies : individual : NGC 1399
  • galaxies : kinematics and dynamics
  • galaxies : star clusters
  • GLOBULAR-CLUSTER SYSTEM
  • ULTRACOMPACT DWARF GALAXIES
  • FORNAX CLUSTER
  • SURFACE BRIGHTNESS
  • CENTRAL REGION
  • STAR-CLUSTERS
  • SPECTROSCOPY
  • KINEMATICS
  • EVOLUTION
  • NGC-1404

Cite this

Firth, P., Drinkwater, M. J., Evstigneeva, E. A., Gregg, M. D., Karick, A. M., Jones, J. B., & Phillipps, S. (2007). Compact stellar systems around NGC 1399. Monthly Notices of the Royal Astronomical Society, 382(3), 1342-1352. https://doi.org/10.1111/j.1365-2966.2007.12474.x