Abstract
Dark Matter supposedly dominates the extragalactic Universe (Peebles 1993; Peacock 1998; Moore et al. 1999; D’Onghi & Lake 2004), yet no dark structure of galactic proportions has ever been convincingly identified. Earlier (Minchin et al. 2005) we suggested that VIRGOHI 21, a 21-cm source we found in the Virgo Cluster at Jodrell Bank using single-dish observations (Davies et al. 2004), was probably such a dark galaxy because of its broad line-width (∼200 km s−1) unaccompanied by any visible gravitational source to account for it. We have now imaged VIRGOHI 21 in the neutral-hydrogen line, and have found what appears to be a dark, edge-on, spinning disc with the mass and diameter of a typical spiral galaxy. Moreover the disc has unquestionably interacted with NGC 4254, a luminous spiral with an odd one-armed morphology, but lacking the massive interactor normally linked with such a feature. Published numerical models (Vollmer et al. 2005) of NGC 4254 call for a close interaction ∼108 years ago with a perturber of ∼1011 solar masses. This we take as further, independent evidence for the massive nature of VIRGOHI 21.
Original language | English (US) |
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Pages (from-to) | 101-106 |
Number of pages | 6 |
Journal | Astrophysics and Space Science Proceedings |
Issue number | 202409 |
DOIs | |
State | Published - 2007 |
Event | International Conference on Island Universe: Structure and Evolution of Disk Galaxies, 2005 - Terschelling, Netherlands Duration: Jul 3 2005 → Jul 5 2005 |
Keywords
- Dark matter
- Galaxies: Intergalactic medium
- Galaxies: Peculiar
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Computer Science Applications
- Spectroscopy
- Space and Planetary Science
- Nuclear and High Energy Physics