SIMBAD references

2007ApJ...668..806M - Astrophys. J., 668, 806-814 (2007/October-3)

A dark core in Abell 520.


Abstract (from CDS):

The rich cluster Abell 520 (z=0.201) exhibits truly extreme and puzzling multiwavelength 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 h70M/L☉B) 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 h70M/L☉B), 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.

Abstract Copyright:

Journal keyword(s): Cosmology: Dark Matter - galaxies: clusters: individual (Abell 520) - Cosmology: Gravitational Lensing - X-Rays: Galaxies: Clusters

Simbad objects: 3

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