Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the origin of the central 1" hole in the stellar disk of Sgr A* and
  the Fermi gamma-ray bubbles   The supermassive black hole Sgr A* at the center of the Galaxy is surrounded
by two misaligned disks of young, massive stars extending from ~0.04 to 0.4 pc.
The stellar surface density increases as ~ r^-2 towards Sgr A* but is truncated
within 1" (0.04pc). We explore the origin of this annulus using a model in
which star formation occurs in a disk of gas created through the partial
capture of a gas cloud as it sweeps through the inner few parsecs of the galaxy
and temporarily engulfs Sgr A*. We identify the locations within which star
formation and/or accretion onto Sgr A* take place. Within 0.04 pc the disk is
magnetically active and the associated heating and enhanced pressure prevents
the disk from becoming self gravitating. Instead, it forms a magneto-turbulent
disk that drains onto Sgr A* within 3 Myr. Meanwhile, fragmentation of the gas
beyond the central 0.04 pc hole creates the observed young stellar disk. The
two large scale bubbles of gamma-ray emission extending perpendicular to the
Galactic plane may be created by a burst of accretion of ~10^5 Msun of gas
lying between 0.01 and 0.03 pc. The observed stellar ages imply that this
capture event occurred ~10^6.5 yr ago, thus such events occurring over the life
time of the Galaxy could have significantly contributed to the current mass of
Sgr A* and to the inner few parsec of the nuclear star cluster. We suggest that
these events also occur in extragalactic systems.

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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc