Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of tidal interactions on the gas flows of elliptical galaxies   During a Hubble time, cluster galaxies may undergo several mutual encounters
close enough to gravitationally perturb their hot, X-ray emitting gas flows. We
ran several 2D, time dependent hydrodynamical models to investigate the effects
of such perturbations on the gas flow inside elliptical galaxies. In
particular, we studied in detail the modifications occurring in the scenario
proposed by D'Ercole et al. (1989), in which the galactic interstellar medium
produced by the aging galactic stellar population, is heated by SNIa at a
decreasing rate. We find that, although the tidal interaction in our models
lasts less than 1 Gyr, its effect extends over several Gyrs. The tidally
induced turbulent flows create dense filaments which cool quickly and accrete
onto the galactic center, producing large spikes in the global Lx. Once this
mechanism starts, it is fed by gravity and amplified by SNIa. In cooling flow
models without supernovae the amplitude of the Lx fluctuations due to the tidal
interaction is substantially reduced. We conclude that, if SNIa significantly
contribute to the energetics of the gas flows in ellipticals, then the observed
spread in the Lx-Lb diagram may be caused, at least in part, by this mechanism.
On the contrary, tidal interactions cannot be responsible for the observed
spread if the pure cooling flow scenario applies (abridged).

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The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc