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Maximum feedback and dark matter profiles of dwarf galaxies
The observed rotation curves of dark matter-dominated dwarf galaxiesindicate low-density cores, contrary to the predictions of CDM models. Apossible solution of this problem involves stellar feedback. A strongbaryonic wind driven by vigorous star formation can remove a largefraction of the gas, causing the dark matter to expand. Using bothnumerical and analytical techniques, we explore the maximum effect ofthe feedback with an instantaneous removal of the gaseous disc. Theenergy input depends on the compactness of the disc, hence the specificangular momentum of the disc. For the plausible cosmological parametersand a wide range of the disc angular momenta, the feedback isinsufficient to destroy the central halo cusp, while the inner densityis lowered only by a modest factor of 2 to 6. Any realistic modelling ofthe feedback would have even lesser impact on dark matter. We find thatno star formation effect can resolve the problems of CDM cusps.
| Accurate Positions for MCG Galaxies
We have measured accurate celestial coordinates for 4741 extragalacticobjects, primarily drawn from a list of MCG galaxies with no recentlypublished accurate positions. The standard deviations in the newpositions depend slightly on the measurement method but are on the orderof 1.0" to 1.2". Standard deviations in the original MCG positions areconfirmed to be at the 1.5′-2.0′ level. These new positionswere integrated into NED in 1997 December.
| A list of some corrections to Zwicky's Catalogue of Galaxies and Clusters of Galaxies
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