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arXiv · 1902.06791

Chandra observations of the Abell S0295 cluster

Aurelia Pascut·John P. Hughes
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Abstract

We present deep ($205 \rm ks$), \Chandra observations of the \ab295 binary merging cluster ($z=0.30$). In the X-ray image, the secondary component is clearly visible as a surface brightness peak, while the primary cluster has a flatter distribution. We found cool gas ($\sim 6 \rm keV$) associated with the secondary, while the central temperature of the primary does not deviate significantly from the mean temperature of the cluster of $\sim 9.5 \rm keV$. In the vicinity of the primary's core we found the hottest region in the cluster accompanied by a surface brightness discontinuity. We propose that this region corresponds to a shock, for which we estimate a Mach number of $1.24_{-0.22}^{+0.30}$. We found other merger signatures such as a plume of cool gas emerging from the primary cluster and a cold front and a possible bow shock (Mach number of $1.74_{-0.74}^{+1.02}$) leading the secondary cluster. Based on the observed properties in comparison to binary merger simulations from the literature we propose for \ab295 a low mass ratio, off-axis merging scenario, with secondary close to first apocentre. Comparison of our results with strong lensing observations of \ab295 from \cite{Cibirka2018} shows an offset between the total mass peak and the bulk of the gas distribution in the primary cluster. The properties of the merger and the existence of the offset between mass peak and gas make \ab295 a promising candidate for the study of mergers involving non-cool core clusters and the nature of dark matter.

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Aurelia Pascut, John P. Hughes. 2019-02-18. Chandra observations of the Abell S0295 cluster. https://doi.org/10.3847/1538-4357%2Fab07b1

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