Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cloud-cloud collisions in the common foot point of molecular loops 1 and
  2 in the Galactic Center   Recent large-area, deep CO surveys in the Galactic disk have revealed the
formation of ~50 high-mass stars or clusters triggered by cloud-cloud
collisions (CCCs). Although the Galactic Center (GC) -- which contains the
highest volume density of molecular gas -- is the most favorable place for
cloud collisions, systematic studies of CCCs in that region are still
untouched. Here we report for the first time evidence of CCCs in the common
foot point of molecular loops 1 and 2 in the GC. We have investigated the
distribution of molecular gas toward the foot point by using a methodology for
identifying CCCs, and we have discovered clear signatures of CCCs. Using the
estimated displacements and relative velocities of the clouds, we find the
elapsed time since the beginnings of the collisions to be 105-6 yr. We consider
possible origins for previously reported peculiar velocity features in the foot
point and discuss star formation triggered by CCCs in the GC.

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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
2
The categories of this paper are: math
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The categories of this paper are: gr-qc
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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: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: cs
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org