Acceleration and propagation of ultra high energy cosmic rays in the Local Universe

Distribution of matter in the Local Universe (up to ~ 100 Mpc), especially in a Virgo Supercluster region (~20 Mpc) is strongly nonuniform and includes all elements of large scale structure: galaxies and their clusters, superclusters, filaments, sheets and voids. On its smallest scale, our Galaxy and its similar galaxy M31 (Andromeda Nebula) at a distance 770 kpc, together with dozens of dwarf galaxies, form the Local Group of Galaxies. Local group contained in Local Sheet – suchlike pancake concentration of galaxies with radius about 5 Mpc and thickness 1.5 Mpc. This structure is a part of Local Filament – cylindrical region with higher density of matter, that join us to more powerful filament, that concludes Virgo Supercluster and connects two highest matter concentrations in Local Universe – supercluster Great Attractor (70 Mpc) and Perseus-Pisces supercluster (60 Mpc). Extragalactic magnetic field (EGMF) distribution is expected to follow the baryonic matter density distribution. Ultra high energy cosmic rays (UHECRs, E>1018 eV) from extragalactic sources will undergo significant deviations in EGMF, which makes it difficult to search their sources. But for extremely high energy cosmic rays (EHECRs, E>5·1019 eV), that are on the top of cosmic rays energy spectrum (the biggest detected energy of cosmic rays is above 1020 eV), influence of EGMF can be negligible, and their arrival direction can correlate with source position. They carry an important information, about the physics of fundamental interactions beyond the standard model, but still unknown to their origins and mechanisms of acceleration. In addition, a flux of nuclear component of UHECRs decreases in result of nuclear photo-disintegration due to interaction with microwave and infrared background. These processes are significant for protons (hydrogen nuclei), for which the major losses are born of electron-positron pairs and photo-pions reactions. For multi nucleon nucleuses significant process of weakening is photo-disintegration with chemical composition change of main nuclei. In our work we estimate the influence of these factors on the propagation of the UHECRs from sources in the Local Universe, in particular we have investigated the mean free path and magnetic deflection of H(p), He, O, Si and Fe nuclei. For potential sources of UHECRs in the Local Universe, such as Virgo supercluster, Great Attractor and Perseus-Pisces supercluster, we have estimated types and energies of nuclei that can reach the Earth, and, in the same time, can save a connection of arrival directions with source position within 1 rad.

Visualization of structures and cosmic flows in the local Universe

A visualization of 3D structures and cosmic flows is presented using information from the Extragalactic Distance Database V8k redshift catalog and peculiar velocities from the Cosmicflows-1 survey. Structures within a volume bounded at 8000 km s−1 on the cardinal Supergalactic axes are explored in terms of both displaying the positions of the 30,124 galaxies of the catalog and its reconstructed luminosity density field, corrected to account for growing incompleteness with increasing distance. Cosmography of the local Universe is discussed with the intent to identify the most prominent structures, including voids, galaxy clusters, filaments, and walls. The mapping also benefits from precise distance measures provided through the Cosmicflows-1 observational program. Three-dimensional visualizations of the coherent flows of galaxies in the nearby Universe are presented, using recent results based on reconstruction of cosmic flows with the Wiener filter approach. The three major components of the Milky Way's motion, namely expulsion from the Local Void, infall toward the Virgo Cluster, and the bulk flow of the historic Local Supercluster toward the Great Attractor are illustrated using different visualization techniques and analyzed in light of the cosmography derived from the V8k redshift and Cosmicflows-1 distance catalogs.