2001A&A...369..736Y


Query : 2001A&A...369..736Y

2001A&A...369..736Y - Astronomy and Astrophysics, volume 369, 736-741 (2001/4-3)

Surface-brightness profiles of dwarf galaxies in the NGC 5044 Group: Implications for the luminosity-shape and scalelength-shape relationships as distance indicators.

YOUNG C.K. and CURRIE M.J.

Abstract (from CDS):

In a recent paper, which presents CCD photometry for fifteen dwarf and intermediate early-type galaxies in the NGC 5044 Group, it has been claimed that ``a few relatively bright galaxies with ``convex'' profiles destroy the known relation between total magnitude and the ``shape'' parameter... thus ruling out the use of this relation as a distance indicator for individual galaxies''. In the same paper, further reasons were cited supposedly ``limiting also its use as a distance indicator for groups of galaxies''. We demonstrate that none of the three relatively bright galaxies cited as possessing ``convex'' profiles actually has a convex profile, and that one of these objects should be excluded because it is a late-type galaxy. Of the two remaining objects, one has an anomalous profile shape whilst the other is brighter than one might expect from its colour alone. However, we show that all of the other issues raised have already been accounted for by Young & Currie (1994MNRAS.268L..11Y, 1995MNRAS.273.1141Y & 1998A&A...333..795Y). The main implications of the new observations are: (1) that the case of one galaxy with an anomalous profile shape, N42, highlights the need for some a priori criteria to be defined in order to establish objectively which objects are not suitable for distance determinations; and (2) on the basis of another unusual galaxy, N50, colour has now been shown to be a poorer discriminant between objects of the same profile shape and scalelength (but of different central surface brightness) than previously thought. How significant this latter problem is depends on how common N50-like objects are. This consideration reinforces the case for always using the more general scalelength-shape relationship of Young & Currie (1995MNRAS.273.1141Y) in preference to the luminosity-shape one of Young & Currie (1994MNRAS.268L..11Y). Reassuringly, through a re-analysis of the same CCD photometry, we find that NGC 5044 Group galaxies observe a tight scalelength-shape relationship. This finding supports the view that the scalelength-shape relationship is a viable distance indicator.

Abstract Copyright:

Journal keyword(s): galaxies: structure - galaxies: photometry - galaxies: fundamental parameters - galaxies: elliptical and lenticular, cD - galaxies: distances and redshifts - galaxies: clusters: individual: NGC 5044 Group

CDS comments: Galaxies N are [FS90] NGC 5044

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 6dFGS gJ131356.2-161624 GiG 13 13 56.228 -16 16 24.42   15.5       ~ 21 0
2 LEDA 83813 GiG 13 14 07.38048 -16 25 36.3828   16.6       ~ 13 0
3 6dFGS gJ131417.3-162619 GiG 13 14 17.333 -16 26 18.91   15.9       ~ 15 0
4 NAME NGC 5044 Group GrG 13 14 22.7 -16 32 04           ~ 181 0
5 LEDA 83827 GiG 13 14 31.23 -16 22 47.6   15.4       ~ 16 0
6 6dFGS gJ131434.9-162929 GiG 13 14 34.8649708152 -16 29 28.782962196   15.8       ~ 17 0
7 FSG V-66 GiG 13 14 53 -16 32.8   16.7       ~ 4 0
8 LEDA 83860 GiG 13 15 21.60 -16 36 08.0   17.4       ~ 10 0
9 NGC 5044 BiC 13 15 23.9607836592 -16 23 07.547751744   11.9   10.74   ~ 501 0
10 LEDA 83871 GiG 13 15 32.40 -16 38 12.0   18.8       ~ 9 0
11 [FS90] NGC 5044 95A GiG 13 15 38.6 -16 38 27           ~ 4 0
12 FSG V-122 GiG 13 16 31 -16 02.0   18.4       ~ 4 0

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