Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Understanding the Fundamental Plane and the Tully Fisher Relation   The relation between early type galaxy size, surface brightness and velocity
dispersion, "the fundamental plane", has long been understood as resulting from
equilibrium in their largely pressure supported stellar dynamics. The
dissipation and feedback involved in reaching such an equilibrium through
merger formation of these galaxies over cosmic time can be responsible for the
orientation of the plane. We see a correlation between surface brightness
enhancement and youth in the 6dF Galaxy Survey. Correlations of this `tilt'
with stellar mass, age, concentration, shape and metallicity now point the
direction for further work on the resolved kinematics and structure of these
nearby galaxies and on their initial mass function and dark matter component.
  On the face of it, the Tully Fisher relation is a simpler one dimensional
scaling relation. However, as late type galaxies have bulges as well as disks,
and, as the surface density of disks is only standard for the more massive
galaxies, additional parameters are involved.

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The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
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The categories of this paper are: econ
2
The categories of this paper are: math
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics