Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constraints on dark energy from the Ly{\alpha} forest baryon acoustic
  oscillations measurement of the redshift 2.3 Hubble parameter   We use the Busca et al. (2012) measurement of the Hubble parameter at
redshift z = 2.3 in conjunction with 21 lower z measurements, from Simon et al.
(2005), Gaztanaga et al. (2009), Stern et al. (2010), and Moresco et al.
(2012), to place constraints on model parameters of constant and time-evolving
dark energy cosmological models. The inclusion of the new Busca et al. (2012)
measurement results in H(z) constraints significantly more restrictive than
those derived by Farooq et al. (2012). These H(z) constraints are now more
restrictive than those that follow from current Type Ia supernova (SNIa)
apparent magnitude measurements (Suzuki et al. 2012). The H(z) constraints by
themselves require an accelerating cosmological expansion at about 2-sigma
confidence level, depending on cosmological model and Hubble constant prior
used in the analysis. A joint analysis of H(z), baryon acoustic oscillation
peak length scale, and SNIa data favors a spatially-flat cosmological model
currently dominated by a time-independent cosmological constant but does not
exclude slowly-evolving dark energy density.

1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph