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Merger Dynamics of the Pair of Galaxy Clusters -- A399 and A401

Qirong Yuan·Pengfei Yan·Yanbin Yang·Xu Zhou
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Abstract

Convincing evidence of a past interaction between two rich clusters A399 and A401 was recently found by the X-ray imaging observations. In this paper we examine the structure and dynamics of this pair of galaxy clusters. A mixture-modeling algorithm has been applied to obtain a robust partition into two clusters, which allows us to discuss the virial mass and velocity distribution for each cluster. Assuming that these two clusters follow a linear orbit and they have once experienced a close encounter, we model the binary cluster as a two-body system. As a result, four gravitationally bound solutions are obtained. The recent X-ray observations seem to favor a scenario in which the two clusters with a true separation of $5.4h^{-1}$ Mpc are currently expanding at 583 km/s along the direction with a projection angle of 67.5 degree, and they will reach a maximum extent of $5.65h^{-1}$ Mpc in about $1.0h^{-1}$ Gyr.

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Qirong Yuan, Pengfei Yan, Yanbin Yang, Xu Zhou. 2005-02-28. Merger Dynamics of the Pair of Galaxy Clusters -- A399 and A401. https://doi.org/10.1088/1009-9271%2F5%2F2%2F002

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