207 research outputs found

    Introducing the Dark Energy Universe Simulation Series (DEUSS)

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    In this "Invisible Universe" proceedings, we introduce the Dark Energy Universe Simulation Series (DEUSS) which aim at investigating the imprints of realistic dark energy models on cosmic structure formation. It represents the largest dynamical dark energy simulation suite to date in term of spatial dynamics. We first present the 3 realistic dark energy models (calibrated on latest SNIa and CMB data): LambdaCDM, quintessence with Ratra-Peebles potential, and quintessence with Sugra potential. We then isolate various contributions for non-linear matter power spectra from a series of pre-DEUSS high-resolution simulations (130 million particles). Finally, we introduce DEUSS which consist in 9 Grand Challenge runs with 1 billion particles each thus probing scales from 4 Gpc down to 3 kpc at z=0. Our goal is to make these simulations available to the community through the "Dark Energy Universe Virtual Observatory" (DEUVO), and the "Dark Energy Universe Simulations" (DEUS) consortium.Comment: 6 pages, 3 figures, to appear in the AIP proceedings of the 'Invisible Universe International Conference', UNESCO-Paris, June 29-July 3, 200

    Dampak Pandemi Covid-19 Terhadap Pola Prediksi Return Saham Berdasarkan Harga Minyak Dunia

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    The Covid-19 pandemic has had a very serious impact, not only on the health sector, but also on the economic sector. Investors cannot predict the effect of a decline or increase in world oil prices during the Covid-19 pandemic on their investment choice decisions. Through this research, an analysis will be carried out on whether Covid-19 will have an influence on the effect of the relationship between world oil prices and stock return predictions using daily Jakarta Composite Index (JCI)  data from 03/01/2011 to 14/03/2022. The data to be analyzed will be divided into 3 types of data panels to facilitate the analysis in finding a comparison of the effect of Covid-19 based on a certain period of time. Panel A presents full sample data, Panel B contains pre Covid-19 sample data and Panel C presents data for samples during the time of Covid-19. Based on the results of the study, it can be inffered that the effect of the Covid-19 pandemic can decrase the effectiveness of economic activities and make the capital market unstable, so that the effect of oil prices on stock returns is inaccurat

    The Solar Neutrino Problem Has Not Been Solved

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    A closer look at the data collected from different detectors, reveal that the so-called solar neutrino problem is far from being solved. And contrary to the assessment of the Nobel Committee, the experimental results from the Sudbury Neutrino Observatory cannot be a confirmation of the Standard Solar Model. In fact, the obsoleteness of the current model has been recently exposed by the crisis of solar abundance. Furthermore, using images obtained by the Solar Dynamics Observatory, researchers found the convective motions (the plasma motions at the Sun's interior) to be nearly 100 times smaller than current theoretical expectations

    Two-Phased Intra-Cluster Medium in the Centaurus Cluster of Galaxies

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    ASCA and ROSAT data of the Centaurus cluster were analyzed. A central excess in the radial brightness profile is found in the hard energy band up to 10keV. This requires a deeper central potential than a King-type one. A double-beta brightness distribution gives a good account of the data. A deprojected energy spectrum within a spherical region of radius 30 kpc at the cluster center indicates that the ICM cannot be isothermal there. Simultaneous fitting of the three (PSPC, GIS, and SIS) energy spectra extracted from the central 3' region showed that a two-temperature model that has temperatures of 1.4keV and 4.4keV and a common metallicity of 1.0 solar with the Galactic absorption gives the best description to the spectra. A cooling-flow spectral model did not give satisfactory fit. A 3-dimensional cluster model incorporating the two-phase picture, the double-beta brightness distribution, and the central metallicity increase reproduced the overall ASCA and ROSAT data successfully. The derived spatial distribution of the dark matter deviates from a King-type profile exhibiting a central excess, which is consistent with the Navvaro-Frenk-White model. The iron is revealed to be more widely spread than stars, which may have been caused by energetic supernovae and the motion of the cD galaxy. Since the derived characteristics of the cool phase including the temperature, angular extent, gas mass, and metallicity, are on a smooth extension of those of inter-stellar medium (ISM) of elliptical galaxies, the cool phase can be regarded as the ISM associated with the cD galaxy. The cool-phase X-ray emission is presumably sustained by energies dissipated by infalling mass to the cD galaxy in the course of cluster evolution.Comment: accepted for publication in Ap
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