Distance determination to NGC 55 from the planetary nebula luminosity function

• Published in: Astronomy and astrophysics (Berlin) Vol. 455; no. 3; pp. 891 - 896
• Main Authors: Van de Steene, G. C., Jacoby, G. H., Praet, C., Ciardullo, R., Dejonghe, H.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.09.2006
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; galaxies: clusters: individual: Sculptor Group; galaxies: distances and redshifts; galaxies: individual: NGC 55; planetary nebulae: general; Red shift; planetary nebulae: general; Local group; Planetary nebulae; Galaxy clusters; Continuum; galaxies: distances and redshifts; galaxies: individual: NGC 55; galaxies: clusters: individual: Sculptor Group; Galaxy groups; Distance measurement; Spiral galaxies; Luminosity function
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20053475

We analysed [O III], Hα, 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]λ5007 Planetary Nebula Luminosity Function (PNLF) and determined a most likely distance of 2.30 ± 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.