Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strong Lensing Analysis of the Galaxy Cluster MACS J1319.9+7003 and the
  Discovery of a Shell Galaxy   We present a strong-lensing (SL) analysis of the galaxy cluster MACS
J1319.9+7003 ($z=0.33$, also known as Abell 1722), as part of our ongoing
effort to analyze massive clusters with archival {\it HST} imaging. We
spectroscopically measured with Keck/MOSFIRE two galaxies multiply-imaged by
the cluster. Our analysis reveals a modest lens, with an effective Einstein
radius of $\theta_{e}(z=2)=12\pm1$", enclosing $2.1\pm0.3\times10^{13}$
$M_{\odot}$. We briefly discuss the SL properties of the cluster, using two
different modeling techniques, and make the mass models
publicly-available\footnote{ftp://wise-ftp.tau.ac.il/pub/adiz/MACS1319/}.
Independently, we identified a noteworthy, young Shell Galaxy (SG) system
forming around two likely interacting cluster members, 20" north of the BCG.
SGs are rare in galaxy clusters, and indeed, a simple estimate yields that they
are only expected in roughly one in several dozen, to several hundred, massive
galaxy clusters (the estimate can easily change by an order-of-magnitude within
a reasonable range of characteristic values relevant for the calculation).
Taking advantage of our lens model best-fit, mass-to-light scaling relation for
cluster members, we infer that the total mass of the SG system is
$\sim1.3\times10^{11}$ M$_{\odot}$, with a host-to-companion mass ratio of
about 10:1. Despite being rare in high density environments, the SG constitutes
an example to how stars of cluster galaxies are being efficiently redistributed
to the Intra Cluster Medium. Dedicated numerical simulations for the observed
shell configuration, perhaps aided by the mass model, might cast interesting
insight on the interaction history and properties of the two galaxies. An
archival HST search in galaxy cluster images can reveal more such systems.

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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg