Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational torques imply molecular gas inflow towards the nucleus of
  M51   The transport of gas towards the centre of galaxies is critical for black
hole feeding and, indirectly, it can control active galactic nucleus (AGN)
feedback. We have quantified the molecular gas inflow in the central R<1kpc of
M51 to be 1 Msun/yr, using a new gravitational torque map and the molecular gas
traced by the PdBI Arcsecond Whirlpool Survey (PAWS). The nuclear stellar bar
is responsible for this gas inflow. We have also used torque profiles to
estimate the location of dynamical resonances, suggesting a corotation for the
bar at R~20", and a corotation for the spiral at R~100". We demonstrate how
important it is to correct 3.6um images for dust emission in order to compute
gravitational torques, and we carefully examine further sources of uncertainty.
Our observational measurement of gas inflow can be compared with nuclear
molecular outflow rates and provide useful constraints for numerical
simulations.

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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: cs
24
The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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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: physics