| 1. |
- Abdalla, E., et al.
(författare)
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Cosmology intertwined : A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies
- 2022
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Ingår i: Journal of High Energy Astrophysics. - : Elsevier BV. - 2214-4048 .- 2214-4056. ; 34, s. 49-211
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Tidskriftsartikel (refereegranskat)abstract
- The standard Λ Cold Dark Matter (ΛCDM) cosmological model provides a good description of a wide range of astrophysical and cosmological data. However, there are a few big open questions that make the standard model look like an approximation to a more realistic scenario yet to be found. In this paper, we list a few important goals that need to be addressed in the next decade, taking into account the current discordances between the different cosmological probes, such as the disagreement in the value of the Hubble constant H0, the σ8–S8 tension, and other less statistically significant anomalies. While these discordances can still be in part the result of systematic errors, their persistence after several years of accurate analysis strongly hints at cracks in the standard cosmological scenario and the necessity for new physics or generalisations beyond the standard model. In this paper, we focus on the 5.0σ tension between the Planck CMB estimate of the Hubble constant H0 and the SH0ES collaboration measurements. After showing the H0 evaluations made from different teams using different methods and geometric calibrations, we list a few interesting new physics models that could alleviate this tension and discuss how the next decade's experiments will be crucial. Moreover, we focus on the tension of the Planck CMB data with weak lensing measurements and redshift surveys, about the value of the matter energy density Ωm, and the amplitude or rate of the growth of structure (σ8,fσ8). We list a few interesting models proposed for alleviating this tension, and we discuss the importance of trying to fit a full array of data with a single model and not just one parameter at a time. Additionally, we present a wide range of other less discussed anomalies at a statistical significance level lower than the H0–S8 tensions which may also constitute hints towards new physics, and we discuss possible generic theoretical approaches that can collectively explain the non-standard nature of these signals. Finally, we give an overview of upgraded experiments and next-generation space missions and facilities on Earth that will be of crucial importance to address all these open questions.
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| 2. |
- Bursa, M., et al.
(författare)
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The timescale of encircling light
- 2007
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Ingår i: Silesian University in Opava. ; , s. 21-25
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Konferensbidrag (refereegranskat)abstract
- We show that in some astronomical sources containing black holes, the signature of the circular photon orbit may be detected by searching for the shortest timescale in the variability data. A positive detection would provide the direct empirical support for Einstein's general relativity in its super-strong field limit, relevant to black holes.
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| 3. |
- Mazur, S., et al.
(författare)
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A strike-slip terrane boundary in Wedel Jarlsberg Land, Svalbard, and its bearing on correlations of SW Spitsbergen with the Pearya terrane and Timanide belt
- 2009
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Ingår i: Journal of the Geological Society. - : Geological Society of London. - 0016-7649 .- 2041-479X. ; 166:Part 3, s. 529-544
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Tidskriftsartikel (refereegranskat)abstract
- Southwest Spitsbergen, Wedel Jarlsberg Land consists of two Proterozoic terranes with differing structural and metamorphic histories. The northern terrane experienced two Early Palaeozoic deformation events both accompanied by greenschist-facies metamorphism of similar grade. The southern terrane records a Neoproterozoic pervasive amphibolite-facies metamorphism and strong deformational fabric only locally retrogressed during a Caledonian greenschist-grade event. The terranes are seperated by an important sinistral ductile shear zone defined as the Vimsodden Kosibapasset zone, which comprises wrench- and contraction-dominated domains characteristic of strain partitioning in transpression zones; in this case apparently controlled by contrasting rheologies of the juxtaposed crustal domains. The northern terrane of Wedel Jarlsberg Land shares affinities with Pearya in northern Ellesmere Island of Arctic Canada whereas the southern one resembles the Timanide belt of NE Europe. A quantitative approach facilitated by a numerical plate model demonstrates that correlation with Pearya is feasible if sinistral displacement of c. 600 km occurred during the Caledonian orogeny. The correlation with the Timanides is valid if the southern terrane represents an outlier of the Timanide belt seperated from Baltica by the opening of the lapetus Ocean.
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| 4. |
- Goluchowska, Karolina, et al.
(författare)
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The role of crustal contamination in magma evolution of Neoproterozoic metaigneous rocks from Southwest Svalbard
- 2022
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Ingår i: Precambrian Research. - : Elsevier. - 0301-9268 .- 1872-7433. ; 370
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Tidskriftsartikel (refereegranskat)abstract
- Late Neoproterozoic metavolcanic rocks occur along the Southwest coast of Svalbard. The protoliths of the metavolcanic rocks from Wedel Jarlsberg Land and Nordenskiold Land are mainly diabase, basalt and felsic tuff of tholeiitic affinity associated with continental magmatism. We investigate the magma evolution of the meta-volcanic rocks paying particular attention to processes of magma-crust interaction and assess potential sources of crustal contamination. These goals are achieved by employing trace element geochemistry, as well as Sr and Nd isotope geochemistry. Metavolcanic rocks from the South (Orvindalen and Werenskioldbreen) have higher LREE, LILE and Th compared to rocks from the North (Nordenskiold Land), which are relatively enriched in Sr. Incompatible element ratios like Th/La, Th/Nb, La/Nb, Th/Yb and Nb/Yb also decrease from South to North. The Nd-143/Nd-144(635 Ma) ranges from 0.511396 to 0.512356 and increases from South to North. For Sr isotopes, the metavolcanic rocks show a wide range, however in the South we observe Sr-87/Sr-86(635 Ma) of 0.70407-0.73043 and in the North Sr-87/Sr-86(635 Ma) of 0.70410-0.71028. Energy Constrained - Assimilation and Fractional Crystallization (EC-AFC) modelling indicates that the extent of magma contamination is highest in the South. Additionally the modelling suggests fractional crystallization and assimilation of granulite or amphibolite followed by shale for the metavolcanic rocks in the South and for the North mixtures of carbonate and shale contributed. This geographical pattern of assimilation reflects the upper crustal metasedimentary sequences, where phyllites are common in the South (Orvindalen and Werenskioldbreen) and carbonates are more common in the North (Nordenskiold Land). Density contrasts and impermeable layers within the continental crust would likely have acted as barriers to ascending magma, forcing it to stall and providing opportunities for magma-crust interaction.
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