Open AccessA high‐resolution rotation curve of NGC 6822: a test‐case for cold dark matter
Author(s) -
Weldrake D. T. F.,
De Blok W. J. G.,
Walter F.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06170.x
Subject(s) - physics , galaxy rotation curve , astrophysics , dark matter , dwarf galaxy , irregular galaxy , local group , cold dark matter , astronomy , rotation (mathematics) , galaxy , dark galaxy , dwarf spheroidal galaxy , galaxy formation and evolution , interacting galaxy , geometry , mathematics
We present high‐resolution rotation curves of the Local Group dwarf irregular galaxy NGC 6822 obtained with the Australia Telescope Compact Array. Our best curves have an angular resolution of 8 arcsec or 20 pc and contain some 250 independent points. The stellar and gas components of NGC 6822 cannot explain the shape of the curve, except for the very inner regions, and NGC 6822 is consequently very dark‐matter‐dominated. There is no evidence for the presence of a steep density cusp down to scales of ∼20 pc , contrary to the predictions of cold dark matter.