Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Keck Spectropolarimetry of BALQSO   Spectropolarimetry of broad absorption line quasi-stellar objects with the W.
M. Keck Telescope is used to put constraints on their nuclear structure. If the
continuum polarization is due to electron (or dust) scattering, then the
scattered and direct rays probe the nucleus along multiple lines of sight,
which suffer differing amounts of absorption. Multiple sources of polarized
light contribute to the quasar emission, and the relative sizes and symmetries
of these sources can be ascertained. The size of the electron scattering region
relative to continuum source, broad emission line region, and broad absorption
line region is determined using spectropolarimetry. The geometries of the
scattering and broad absorption line regions are discussed in an attempt to
discriminate between polar and equatorial outflows. The variation of
polarization with velocity in the broad absorption troughs may also be used to
study the dynamics of the absorbing gas.

22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs