H I and mass distribution in the dwarf 'regular' galaxy UGC 2259

Abstract

view Abstract Citations (79) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS H I and Mass Distribution in the Dwarf "Regular" Galaxy UGC 2259 Carignan, Claude ; Sancisi, Renzo ; van Albada, Tjeerd S. Abstract H I synthesis observations of the dwarf "regular" galaxy UGC 2259 are presented. This system has a symmetrical H I distribution extending over 2D_25_ and a regular velocity field which shows no sign of departure from axial symmetry. It is therefore most suitable for studying the mass distribution in late-type spirals. Despite the fact that UGC 2259 is fainter than most other objects of the same morphological type, its H I properties are typical of an Scd galaxy. While other low-luminosity galaxies studied so far in H I exhibit solid-body type rotation curves, this dwarf system has a flat rotation curve similar to what is seen in more luminous spirals. The main difference between UGC 2259 and other low-luminosity galaxies is its regular appearance. Studying the mass distribution, it is found that a "minimum" dark isothermal halo with one-dimensional velocity dispersion σ = 55 km s^-1^ and core radius r_c_ = 5.5 kpc is needed to reproduce the obseved rotation curve. In this case, the dark halo and the luminous disk contribute about equally to the circular velocity at the Holmberg radius. However, because the rotation curve is still slightly rising in the outer parts, the halo parameters are not as constrained as in the case of an exactly flat rotation curve. This result, by extending the luminosity range of well- studied galaxies, strengthens earlier suggestions that the ratio of dark to luminous matter is independent of galaxy luminosity. Publication: The Astronomical Journal Pub Date: January 1988 DOI: 10.1086/114610 Bibcode: 1988AJ.....95...37C Keywords: Dwarf Galaxies; Galactic Mass; H I Regions; Mass Distribution; Dark Matter; Galactic Evolution; Mass To Light Ratios; Spiral Galaxies; Astrophysics; GALAXIES: GENERAL full text sources ADS | data products SIMBAD (2) NED (1)