Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Density Waves Inside Inner Lindblad Resonance: Nuclear Spirals in Disk
  Galaxies   We analyze formation of grand-design two-arm spiral structure in the nuclear
regions of disk galaxies. Such morphology has been recently detected in a
number of objects using high-resolution near-infrared observations. Motivated
by the observed (1) continuity between the nuclear and kpc-scale spiral
structures, and by (2) low arm-interarm contrast, we apply the density wave
theory to explain the basic properties of the spiral nuclear morphology. In
particular, we address the mechanism for the formation, maintenance and the
detailed shape of nuclear spirals. We find, that the latter depends mostly on
the shape of the underlying gravitational potential and the sound speed in the
gas. Detection of nuclear spiral arms provides diagnostics of mass distribution
within the central kpc of disk galaxies. Our results are supported by 2D
numerical simulations of gas response to the background gravitational potential
of a barred stellar disk. We investigate the parameter space allowed for the
formation of nuclear spirals using a new method for constructing a
gravitational potential in a barred galaxy, where positions of resonances are
prescribed.

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The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol