The return of the merging galaxy subclusters of El Gordo?

Abstract

Merging galaxy clusters with radio relics provide rare insights to the merger dynamics as the relics are created by the violent merger process. We demonstrate one of the first uses of the properties of the radio relic to reduce the uncertainties of the dynamical variables and determine the 3D configuration of a cluster merger, ACT-CL J0102-4915, nicknamed El Gordo. From the double radio relic observation and the X-ray observation of a comet-like gas morphology induced by motion of the cool core, it is widely believed that El Gordo is observed shortly after the first core-passage of the subclusters. We employ a Monte Carlo simulation to investigate the three-dimensional (3D) configuration and dynamics of El Gordo. Using the polarization fraction of the radio relic, we constrain the estimate of the angle between the plane of the sky and the merger axis to be $\alpha =21\mathrm{degree}{\pm }_{11}^9$. We find the relative 3D merger speed of El Gordo to be $2400{\pm }_{200}^{400}\mathrm{km}{\mathrm{s}}^{-1}$ at pericenter. The two possible estimates of the time-since-pericenter are $0.46{\pm }_{0.16}^{0.09}$ Gyr and $0.91{\pm }_{0.39}^{0.22}$ Gyr for the outgoing and returning scenario respectively. We put our estimates of the time-since-pericenter into context by showing that if the time-averaged shock velocity is approximately equal to or smaller than the pericenter velocity of the corresponding subcluster in the center of mass frame, the two subclusters are more likely to be moving towards, rather than away, from each other, post apocenter. We compare and contrast the merger scenario of El Gordo with that of the Bullet Cluster, and show that this late-stage merging scenario explains why the southeast dark matter lensing peak of El Gordo is closer to the merger center than the southeast cool core.

Figure 1 explains the configuration of the different components of El Gordo. Figure 9 explains the merger scenario. 20 pages, 23 figures. Accepted by MNRAS

References in corpus (18)

• Astropy: A Community Python Package for Astronomy
• Constraints on the Self-Interaction Cross-Section of Dark Matter from Numerical Simulations of the Merging Galaxy Cluster 1E 0657-5
• Shocks and cold fronts in galaxy clusters
• Particle Acceleration on Megaparsec Scales in a Merging Galaxy Cluster
• Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56
• Introduction to astroML: Machine Learning for Astrophysics
• The speed of the `bullet' in the merging galaxy cluster 1E0657-56
• Colliding clusters and dark matter self-interactions
• Simulating the Bullet Cluster
• The Atacama Cosmology Telescope: Physical Properties and Purity of a Galaxy Cluster Sample Selected via the Sunyaev-Zel'dovich Effect
• Weighing "El Gordo" with a Precision Scale: Hubble Space Telescope Weak-lensing Analysis of the Merging Galaxy Cluster ACT-CL J0102-4915 at z=0.87
• The Radio Relics and Halo of El Gordo, a Massive $z=0.870$ Cluster Merger
• The Cluster-Merger Shock in 1E 0657-56: Faster than the Speeding Bullet?
• Spectral age modelling of the `Sausage' cluster radio relic
• A highly elongated prominent lens at z=0.87: first strong lensing analysis of El Gordo
• A Hydrodynamical Solution for the "Twin-Tailed" Colliding Galaxy Cluster "El Gordo"
• Initial Conditions for Idealised Clusters Mergers, simulating El Gordo
• An approximate theory for substructure propagation in clusters

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