A Dark Core in Abell 520

By A. Mahdavi, H. Hoekstra, Arif Babul, D. Balam, P. Capak. 2007

155 citations recorded by the source corpus.

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 h70 M☉/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 h70 M☉/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.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b0fbc17146bc269d5d32ec69d9dd3520580abe19

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Citations in the corpus

The local dark matter density (2014, background): “The problem poster-child is Abel 520 which was reported to have a ‘dark core’ that correlates well with the X-ray emission but not the galactic light – the exact opposite of the bullet cluster (Mahdavi et al., 2007).”
Masses of Galaxy Clusters from Gravitational Lensing (2013, background): “Using deep CFHT observations, Mahdavi et al. (2007) found a significant peak in the mass reconstruction that coincided with the peak of the X-ray emission, but where almost no cluster galaxies were present.”
Gravitational lensing (2010, background): “A very peculiar case is the cluster A 520, where the galaxies are seen displaced from the coincident dark-matter distribution and X-ray emission [295], see Fig.”
The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827 (2015, background): “…most visibly in collisions like the ‘Bullet Cluster’ 1E0657-56 (Clowe, Gonzalez & Markevitch 2004; Bradač et al. 2006; Clowe et al. 2006), Abell 520 (Mahdavi et al. 2007; Clowe et al. 2012; Jee et al. 2014), MACSJ0025-12 (Bradač et al. 2008), Abell 2744 (Merten et al. 2011) and DLSCL J0916.”
Multiscale cluster lens mass mapping - I. Strong lensing modelling (2009, background): “New lensing results reveal irregular or merging clusters (e.g. Bradač et al. 2006; Jee et al. 2007; Mahdavi et al. 2007).”
Revealing the Properties of Dark Matter in the Merging Cluster MACS J0025.4–1222 (2008, background): “A recent study of the merging cluster A520 by Mahdavi et al. (2007) rests less easily within this simple picture.”
The Canadian Cluster Comparison Project: detailed study of systematics and updated weak lensing masses (2015, background): “The CCCP sample contains several complex, or merging clusters, of which Abell 520 has been studied in particular detail (Mahdavi et al. 2007; Jee et al. 2012, 2014).”
Colliding clusters and dark matter self-interactions (2013, methodology): “In particular, we consider three different systems: System A is representative of Abell 520 (Mahdavi et al. 2007; Jee et al. 2012), System B of the Bullet Cluster (Markevitch et al. 2004; Clowe et al. 2006) and System C of the Musket Ball Cluster (Dawson et al. 2012; Dawson 2013a).”
Combined strong and weak lensing analysis of 28 clusters from the Sloan Giant Arcs Survey (2011, background): “…lensing analysis of several merging clusters of galaxies strongly supports the collisionless nature of dark matter (Clowe et al. 2006; Jee et al. 2007; Bradač et al. 2008; Merten et al. 2011), although a possible case against the collisionless nature has also been discovered (Mahdavi et al. 2007).”
The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology (2012, background): “16 The Train-Wreck Cluster (Abell 520) has been shown to be incompatible with the SMoC because the putative C/WDM particles have separated from the galaxies such that a core of DM is left (Mahdavi et al. 2007; Jee et al. 2012).”
X-ray–optical classification of cluster mergers and the evolution of the cluster merger fraction (2011, background): “…Society C© 2012 RAS Downloaded from https://academic.oup.com/mnras/article-abstract/420/3/2120/978455 by guest on 29 July 2018 Cluster classification and evolution 2131 A520 is a complex system whose unusual morphology led to claims of the presence of a ‘dark core’ (Mahdavi et al. 2007).”
Creation of cosmic structure in the complex galaxy cluster merger Abell 2744 (2011, unknown): “4-1222) (Bradač et al. 2008), the Cosmic Train Wreck (Abell 520) (Mahdavi et al. 2007; Okabe & Umetsu 2008), Abell 2146 (Russell et al. 2010), Abell 521 (Giacintucci et al. 2008; Okabe et al. 2010a) and Abell 3667 (Finoguenov et al. 2010).”