A Dark Core in Abell 520
Citations Over TimeTop 10% of 2007 papers
Abstract
The rich cluster Abell 520 (z=0.201) exhibits truly extreme and puzzling multi-wavelength characteristics. It may best be described as a "cosmic train wreck." It is a major merger showing abundant evidence for ram pressure stripping, with a clear offset in the gas distribution compared to the galaxies (as in the bullet cluster 1E 0657-558). However, the most striking feature is a massive dark core (721 h_70 M_sun/L_sun) in our weak lensing mass reconstruction. The core coincides with the central X-ray emission peak, but is largely devoid of galaxies. An unusually low mass to light ratio region lies 500 kpc to the east, and coincides with a shock feature visible in radio observations of the cluster. Although a displacement between the X-ray gas and the galaxy/dark matter distributions may be expected in a merger, a mass peak without galaxies cannot be easily explained within the current collisionless dark matter paradigm. Interestingly, the integrated gas mass fraction (~0.15), mass-to-light ratio (220 h_70 M_sun/L_sun), and position on the X-ray luminosity-temperature and mass-temperature relations are unremarkable. Thus gross properties and scaling relations are not always useful indicators of the dynamical state of clusters.
Related Papers
- → The ESO Nearby Abell Cluster Survey(2002)130 cited
- → Chandra observation of two shock fronts in the merging galaxy cluster Abell 2146(2010)99 cited
- → Dynamics of [CLC]c[/CLC]D Clusters of Galaxies. IV. Conclusion of a Survey of 25 Abell Clusters(2001)143 cited
- Dynamics of CD Clusters of Galaxies: 4; Conclusion of a Survey of 25 Abell Clusters(2013)
- Gas Temperature Structure of the Medium-Distant Galaxy Cluster Abell 1835 observed with XMM-Newton(2001)