Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Age of the Universe and the Cosmological Constant Determined from
  Cosmic Microwave Background Anisotropy Measurements   If Omega_tot = 1 and structure formed from adiabatic initial conditions then
the age of the Universe, as constrained by measurements of the cosmic microwave
background (CMB), is t_0=14.0 +/- 0.5 Gyr. The uncertainty is surprisingly
small given that CMB data alone constrain neither h nor Omega_Lambda
significantly. It is due to the tight (and accidental) correlation, in these
models, of the age with the angle subtended by the sound horizon on the
last--scattering surface and thus with the well-determined acoustic peak
locations. If we assume either the HST Key Project result h = 0.72 \pm .08 or
simply that h > 0.55, we find Omega_Lambda > 0.4 at 95% confidence--another
argument for dark energy, independent of supernovae observations. Our analysis
is greatly simplified by the Monte Carlo Markov chain approach to Bayesian
inference combined with a fast method for calculating angular power spectra.

18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th