Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How old is the Universe ? Setting new constraints on the age of the
  Universe   There are three independent techniques for determining the age of the
universe: via cosmochronology of long-lived radioactive nuclei, via stellar
modelling and population synthesis of the oldest stellar populations, and via
the precision cosmology that has become feasible with the mapping of the
acoustic peaks in the cosmic microwave background. We demonstrate that all
three methods give completely consistent results, and enable us to set rigorous
bounds on the maximum and minimum ages that are allowed for the universe. We
present new constraints on the age of the universe by performing a multiband
colour analysis of bright cluster ellipticals over a large redshift range
(0.3<z<0.9), which allows us to infer the ages of their stellar populations
over a wide range of possible formation redshifts and metallicities. Applying a
conservative prior to Hubble's constant of H0=70+-15 km/s/Mpc, we find the age
of the universe to be 13.2(+3.6 -2.0) Gyr (1-sigma), in agreement both with the
estimates from type Ia supernovae, as well as with the latest uranium decay
estimates. Without the assumption of any priors, universes older than 18 Gyr
are ruled out by the data at the 90 % confidence level.

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The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: funct-an
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The categories of this paper are: eess