Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tangential Large Scale Structure as a Standard Ruler: Curvature
  Parameters from Quasars   Several observational analyses suggest that matter is spatially structured at
$\approx 130h^{-1}Mpc$ at low redshifts. This peak in the power spectrum
provides a standard ruler in comoving space which can be used to compare the
local geometry at high and low redshifts, thereby constraining the curvature
parameters.
  It is shown here that this power spectrum peak is present in the observed
quasar distribution at $z\sim 2$: qualitatively, via wedge diagrams which
clearly show a void-like structure, and quantitatively, via one-dimensional
Fourier analysis of the quasars' tangential distribution. The sample studied
here contains 812 quasars.
  The method produces strong constraints (68% confidence limits) on the density
parameter $\Omega_0$ and weaker constraints on the cosmological constant
$\lambda_0$, which can be expressed by the relation $ \Omega_0 = (0.24 \pm0.15)
+ (0.10\pm0.08) \lambda_0 $. Independently of $\lambda_0$ (in the range
$\lambda_0 \in [0,1]$), the constraint is $0.1 < \Omega_0 < 0.45$.
  Combination of the present results with SN Type Ia results yields $\Omega_0 =
(0.30\pm0.11) + (0.57\pm0.11) (\lambda_0-0.7),$ $0.55 < \lambda_0 < 0.95,$ (68%
confidence limits). This strongly supports the possibility that the observable
universe satisfies a nearly flat, perturbed
Friedmann-Lema\^{\i}tre-Robertson-Walker model, independently of any cosmic
microwave background observations.

28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th