Primordial Non-Gaussianity from the 21 cm Power Spectrum during the Epoch of Reionization

Primordial non-Gaussianity is a crucial test of inflationary cosmology. We consider the impact of non-Gaussianity on the ionization power spectrum from 21 cm emission at the epoch of reionization. We focus on the power spectrum on large scales at redshifts of 7 to 8 and explore the expected constraint on the local non-Gaussianity parameter f_(NL) for current and next-generation 21 cm experiments. We show that experiments such as SKA and MWA could measure f_(NL) values of order 10. This can be improved by an order of magnitude with a fast-Fourier transform telescope like Omniscope

Planck intermediate results. L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB B-mode analysis

The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the C^(BB)_ℓ angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data

Planck intermediate results. XLVIII. Disentangling Galactic dust emission and cosmic infrared background anisotropies

Using the Planck 2015 data release (PR2) temperature maps, we separate Galactic thermal dust emission from cosmic infrared background (CIB) anisotropies. For this purpose, we implement a specifically tailored component-separation method, the so-called generalized needlet internal linear combination (GNILC) method, which uses spatial information (the angular powerspectra) to disentangle the Galactic dust emission and CIB anisotropies. We produce significantly improved all-sky maps of Planck thermal dust emission, with reduced CIB contamination, at 353, 545, and 857 GHz. By reducing the CIB contamination of the thermal dust maps, we provide more accurate estimates of the local dust temperature and dust spectral index over the sky with reduced dispersion, especially at high Galactic latitudes above b = ±20°. We find that the dust temperature is T = (19.4 ± 1.3) K and the dust spectral index is β = 1.6 ± 0.1 averaged over the whole sky, while T = (19.4 ± 1.5) K and β = 1.6 ± 0.2 on 21% of the sky at high latitudes. Moreover, subtracting the new CIB-removed thermal dust maps from the CMB-removed Planck maps gives access to the CIB anisotropies over 60% of the sky at Galactic latitudes |b| > 20°. Because they are a significant improvement over previous Planck products, the GNILC maps are recommended for thermal dust science. The new CIB maps can be regarded as indirect tracers of the dark matter and they are recommended for exploring cross-correlations with lensing and large-scale structure optical surveys. The reconstructed GNILC thermal dust and CIB maps are delivered as Planck products

The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects

We study the effect of primordial nongaussianity on large-scale structure, focusing upon the most massive virialized objects. Using analytic arguments and N-body simulations, we calculate the mass function and clustering of dark matter halos across a range of redshifts and levels of nongaussianity. We propose a simple fitting function for the mass function valid across the entire range of our simulations. We find pronounced effects of nongaussianity on the clustering of dark matter halos, leading to strongly scale-dependent bias. This suggests that the large-scale clustering of rare objects may provide a sensitive probe of primordial nongaussianity. We very roughly estimate that upcoming surveys can constrain nongaussianity at the level |fNL| <~ 10, competitive with forecasted constraints from the microwave background.Comment: 16 pages, color figures, revtex4. v2: added references and an equation. submitted to PRD. v3: simplified derivation, additional reference

Barents Sea Geology, Petroleum Resources and Commercial Potential

ABSTRACT. Geologically, the Barents Sea is a complex mosaic of basins and platforms. It underwent intracontinental sedimentation from about 240 million years ago to the early Cenozoic, about 60 million years ago, after which it bordered the developing Atlantic and Arctic oceans. Geophysical investigations began during the 1970s, and the first offshore drilling occurred in the early 1980s. In Norwegian waters, drilling has proven 260 –300 billion cubic meters of gas, with minor oil. Most of the reserves are contained in Jurassic sandstones. Exploration problems include the predominance of gas over oil and leakage of hydrocarbons from traps in recent geological time; both are connected with the intense erosion of the Barents Shelf that took place during the Cenozoic. Exploration efforts currently focus on new targets in areas such as the Finnmark Platform, the Nordkapp Basin, the Western Margin, and the area between 74˚30&apos;N and Spitsbergen. Oil accumulations have been discovered in Russian waters offshore from the Timan-Pechora Basin. However, major sedimentary basins west of Novaya Zemlya have yielded the most significant results. The largest finds include the Stokmanovskaya and Ludlovskaya supergiant gas fields. Stokmanovskaya alone has gas reserves in the order of 2500 billion cubic meters. Seismic surveys have documented a large inventory of untested structures, and further resources are probably present in the disputed area between Norwegian and Russian waters. Options for commercial development of both Norwegian and Russian discoveries are currently being evaluated. These include the possible export of liquefied natural gas from the Norwegian Snøhvit Field to the European market. A consortium has carried out feasibility studies on the Russian Stokmanovskaya Field, and gas export solutions are being evaluated. In general, economic exploitation is hindered by the low price of natural gas, the distance to potential markets, difficult logistics, restricted drilling seasons and environmental concerns