Cosmological parameters from large scale structure - geometric versus shape information
By Jan Hamann, S. Hannestad, Julien Lesgourgues, Cornelius Rampf, Y. Wong. 2010
146 citations recorded by the source corpus.
The matter power spectrum as derived from large scale structure (LSS) surveys contains two important and distinct pieces of information: an overall smooth shape and the imprint of baryon acoustic oscillations (BAO). We investigate the separate impact of these two types of information on cosmological parameter estimation for current data, and show that for the simplest cosmological models, the broad-band shape information currently contained in the SDSS DR7 halo power spectrum (HPS) is by far superseded by geometric information derived from the baryonic features. An immediate corollary is that contrary to popular beliefs, the upper limit on the neutrino mass mν presently derived from LSS combined with cosmic microwave background (CMB) data does not in fact arise from the possible small-scale power suppression due to neutrino free-streaming, if we limit the model framework to minimal ΛCDM+mν. However, in more complicated models, such as those extended with extra light degrees of freedom and a dark energy equation of state parameter w differing from -1, shape information becomes crucial for the resolution of parameter degeneracies. This conclusion will remain true even when data from the Planck spacecraft are combined with SDSS DR7 data. In the course of our analysis, we update both the BAO likelihood function by including an exact numerical calculation of the time of decoupling, as well as the HPS likelihood, by introducing a new dewiggling procedure that generalises the previous approach to models with an arbitrary sound horizon at decoupling. These changes allow a consistent application of the BAO and HPS data sets to a much wider class of models, including the ones considered in this work. All the cases considered here are compatible with the conservative 95%-bounds ∑mν < 1.16eV, Neff = 4.8±2.0.
Subfields: Astronomy and Astrophysics, Instrumentation
View Paper: https://www.semanticscholar.org/paper/66dde0c311a7489db91f09de86c0db90eb0273d4
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Citations in the corpus
- Cosmological bounds on pseudo Nambu-Goldstone bosons (2011, background): “The two main effects are a shift in the redshift of matter-radiation equality and the decrease of the density contrast at small scales caused by the neutrino free-streaming [19–22].”
- Nonlinear perturbation theory extension of the Boltzmann code CLASS (2020, unknown): “[86].”
- Sterile Neutrino Fits to Short-Baseline Neutrino Oscillation Measurements (2012, background): “However, the need for additional information from both appearance and disappearance experiments provides strong motivation for pursuing the future experiments discussed in this paper.”
- Thermalisation of light sterile neutrinos in the early universe (2012, methodology): “Including the Sloan Digital Sky Survey (SDSS) data release 7 (DR7) halo power spectrum, [13] found Neff = 4.”
- Neutrino Mass in Cosmology: Status and Prospects (2011, methodology): “, because the nuisance parameters of the bias model are always marginalised at the end of the analysis, this procedure is eectively the same as discarding all (nonlinear) data beyond k>0:1 hMpc 1 [28,29]. Another LSS probe that has gained considerable attention recently is the Lyman-(Ly) forest. ”
- CONSTRAINTS ON COSMOLOGY FROM THE COSMIC MICROWAVE BACKGROUND POWER SPECTRUM OF THE 2500 deg2 SPT-SZ SURVEY (2012, methodology): “To account for the difference between zdrag as calculated by the fitting formula with zdrag as calculated by CAMB, Hamann et al. (2010a) find it necessary to rescale rs by a factor 154.66/150.82.”