EDP Sciences
Free access
Volume 455, Number 3, September I 2006
Page(s) 891 - 896
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20053475

A&A 455, 891-896 (2006)
DOI: 10.1051/0004-6361:20053475

Distance determination to NGC 55 from the planetary nebula luminosity function

G. C. Van de Steene1, G. H. Jacoby2, C. Praet3, R. Ciardullo4 and H. Dejonghe3

1  Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
    e-mail: gsteene@oma.be
2  WIYN Observatory, PO Box 26732, Tucson, AZ, 85726, USA
    e-mail: gjacoby@noao.edu
3  Sterrenkundig Observatorium, Krijgslaan 281, 9000 Gent, Belgium
    e-mail: H.Dejonghe@rug.ac.be
4  Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab University Park, PA 16802, USA
    e-mail: rbc@astro.psu.edu

(Received 19 May 2005 / Accepted 17 May 2006 )

We analysed [O III], H$\alpha$, and continuum images of the Sculptor Group spiral galaxy NGC 55 obtained with the WFI instrument at the 2.2-m telescope of ESO. We identified 21 new planetary nebula candidates. We constructed the [O III]$\lambda$5007 Planetary Nebula Luminosity Function (PNLF) and determined a most likely distance of 2.30 $\pm$ 0.35 Mpc. The distance to NGC 55 is a bit larger than previously determined distances, which means that the Sculptor Group is further away from the Local Group than previously thought. The PNLF distance to NGC 55 is comparable to the PNLF distance of NGC 300 (Soffner et al. 1996, A&A, 306, 9), adding support to the suggestion that these galaxies form a bound pair. There doesn't seem to be a shortage of planetary nebula candidates in this metal poor galaxy.

Key words: planetary nebulae: general -- galaxies: individual: NGC 55 -- galaxies: distances and redshifts -- galaxies: clusters: individual: Sculptor Group

© ESO 2006