Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Chandra Study of the Effects of a Major Merger on the Structure of
  Abell 2319   We present an analysis of a Chandra observation of the massive, nearby galaxy
cluster Abell 2319. A sharp surface brightness discontinuity--suggested by
previous, lower angular resolution X-ray imaging--is clearly visible in the
ACIS image. This roughly 300kpc feature suggests that a major merger is taking
place with a significant velocity component perpendicular to the line of sight.
The cluster emission-weighted mean temperature is 11.8+/-0.6kev, somewhat
higher than previous temperature measurements. The Chandra temperature map of
A2319 reveals substructure resembling that anticipated based on hydrodynamic
simulations of cluster mergers. The merger feature shows a pressure change
across the surface brightness discontinuity by a factor of <=2.5. The higher
density side of the front has a lower temperature, suggesting the presence of a
cold front similar to those in many other merging clusters. The velocity of the
front is roughly sonic.
  We compare bulk properties of the ICM and galaxies in A2319 to the same
properties in a large sample of clusters as a way of gauging the effects of the
major merger. Interestingly, by comparing A2319 to a sample of 44 clusters
studied with the ROSAT PSPC we find that the X-ray luminosity, isophotal size,
and ICM mass are consistent with the expected values for a cluster of its
temperature; in addition, the K-band galaxy light is consistent with the
light--temperature scaling relation derived from a sample of about 100 clusters
studied with 2MASS. Together, these results indicate either that the merger in
A2319 has not been effective at altering the bulk properties of the cluster, or
that there are large but correlated displacements in these quantities.

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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
1
The categories of this paper are: cs
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg