Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamical analysis of galaxy cluster merger Abell 2146   We present a dynamical analysis of the merging galaxy cluster system Abell
2146 using spectroscopy obtained with the Gemini Multi-Object Spectrograph on
the Gemini North telescope. As revealed by the Chandra X-ray Observatory, the
system is undergoing a major merger and has a gas structure indicative of a
recent first core passage. The system presents two large shock fronts, making
it unique amongst these rare systems. The hot gas structure indicates that the
merger axis must be close to the plane of the sky and that the two merging
clusters are relatively close in mass, from the observation of two shock
fronts. Using 63 spectroscopically determined cluster members, we apply various
statistical tests to establish the presence of two distinct massive structures.
With the caveat that the system has recently undergone a major merger, the
virial mass estimate is M_vir = 8.5 +4.3 -4.7 x 10 ^14 M_sol for the whole
system, consistent with the mass determination in a previous study using the
Sunyaev-Zeldovich signal. The newly calculated redshift for the system is z =
0.2323. A two-body dynamical model gives an angle of 13-19 degrees between the
merger axis and the plane of the sky, and a timescale after first core passage
of 0.24-0.28 Gyr.

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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: ao-sci