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%TOC% ---- ---+ Research topics - different intensities at Licencjat/Magister/Doktorat level %STARTINCLUDE% ---++++ CMB/WMAP/Planck - the Missing Fluctuations problem WMAP data are *too* homogeneous on the largest scales to match the infinite flat model, e.g. see Copi et al. 2009 ArXiv:0808.3767. Summarise the evidence; discuss the correlation function versus spherical harmonic interpretations of the data; list possible explanations, including small universe models. ---++++ Topology of the Universe If you are interested in cosmic topology and have good software skills and/or a good understanding of differential geometry, projects are available upon consultation - start reading at MonographCosmo ---++++ Clusters, Lambda, and OCRA/SZ Effect The largest gravitationally collapsed (virialised) objects in the Universe are clusters of galaxies. In principle, these should be easy to use as cosmological tracer objects in various ways. The simplest interpretation of clusters observed by XMM-Newton using the apparent gas fraction at the virial radius appeared to support a high-density (e.g. zero cosmological constant) model - Sadat et al. 2005 AstroPh:0503426, in contradiction to the Concordance Model. Resolving this contradiction may lead to new understanding of the dynamics and outer parts of clusters, e.g. Kay et al. 2007 AstroPh:0611017, Ferramacho, Blanchard 2007 AstroPh:0609822. Could we test the suggested resolution of the paradox using OCRA-f on RT4? ---++++ Dark Energy/Cosmological Constant Summarise the evidence (it did *not* start with the SNe Ia project); list different types of explanations; give arguments for and against the different candidates; investigate the evidence numerically and produce your own plots. See ArXiv:0903.0866 and ArXiv:0904.0975 and references therein. ---++++ Dark Matter (DM) Summarise the evidence; list different types of explanations; give arguments for and against the different candidates; investigate the evidence numerically and produce your own plots. In particular, * the Light Dark Matter hypothesis AstroPh:0507142 seems very interesting (is the 511 keV line emission in the galactic centre due to annihilating LDM?); and * the DAMA/NaI and DAMA/LIBRA results are interesting - see Bernabei et al. (2008), ArXiv:0804.2741 _"the presence of Dark Matter particles in the galactic halo is supported, on the basis of the DM annual modulation signature, at 8.2 σ C.L."_ and Savage et al. (2009), ArXiv:0808.3607 and references therein * Warning: microlensing (OGLE etc.) so far only gives evidence of that DM is (mostly) *not* composed of stellar-mass MACHOs e.g. AstroPh:0607207. %STOPINCLUDE% ---+ już ktoś robi... ---++++ Topology of the Universe Detection * In http://de.arxiv.org/abs/0801.0006, it seems that we may have measured the shape of the Universe, since certain parts of the cosmic microwave background seen by the WMAP satellite appear to be seen twice in different directions on the sky, due to topological lensing. The purpose of the masters/licencjat project is: * Aim: Propose and apply a further test using WMAP data which further tests the hypothesis. This requires: * Reading/writing/managing the WMAP data file with free software computer programs * Statistical analysis * Independently checking that the computer code does the algebraic and statistical analyses correctly _źródło: LambdaStudentTematAbstrakt_ %INCLUDE{"LambdaStudentTematAbstrakt"}% _źródło: LDMStudentTematAbstrakt_ ---++++ Dark Matter - Light Dark Matter (LDM) hypothesis - Galaxy Centre INTEGRAL results * http://arxiv.org/abs/astro-ph/0507142 * Is the 511 keV line emission in the galactic centre due to annihilating LDM? ---+ Stary ---++++ Cosmic String Detection * In http://de.arxiv.org/abs/astro-ph/0410073 Kibble discusses the <del><strike> http://de.arxiv.org/abs/astro-ph/302547 possible detection of a cosmic string which seems to gravitationally lens a background galaxy (Sazhin et al.) In http://de.arxiv.org/abs/astro-ph/0406516 the extra pairs of lensed galaxies predicted by the hypothesis are discussed.</del></strike> - see AstroPh:0601494 Sazhin et al. * Also Schild et al 2004 - AstroPh:0406434 * Aim: Understand the basics about (1) cosmic strings, (2) gravitational lensing versus cosmic string lensing, and test the hypothesis * Calculate the probability of seeing the original pair by chance * Check whether the statistics of expected numbers of lensed images are correct * Propose an independent test of the hypothesis, e.g. using radio observations and prepare an observing proposal * compare with conventional gravitational lensing interpretations * introductions to grav lensing: AstroPh:9606001 - AstroPh:0012423 - AstroPh:0108255 * Schild et al. foreground galaxy as lensing object - AstroPh:0504396 * recent MACHO articles: http://arxiv.org/find/astro-ph/1/ti:+machos/0/1/0/all/0/1 * MACHO debate: are the MW microlensing events only due to known stellar populations? Evans & Belokurov, 2004, _RIP: The Macho Era (1974-2004)_ AstroPh:0411222 vs Griest & Thomas 2004 _Contamination in the MACHO dataset and the puzzle of LMC Microlensing_ AstroPh:0412443 * Nice pictures :) - [[http://antwrp.gsfc.nasa.gov/apod/image/0110/a2218c_hst_big.jpg][Abell 2218]] _źródło: DAMAStudentTematAbstrakt_ ---++++ Dark Matter Detection - DAMA/NaI + Foot et al. * In http://de.arxiv.org/abs/astro-ph/0405282 the 7 year results of the DAMA/NaI dark matter direct detection experiment show a signal significant at 6.3σ according to the authors. An explanation for why a signal from mirror-baryonic matter should be expected in this experiment but not in others with similar cross-section detection parameters is presented in AstroPh:0403043, see also AstroPh:0407623 and references therein. * Aim: Check the experimental and theoretical claims and propose further tests * Try to find an alternative explanation for the DAMA/NaI results without going beyond the Standard Model of particle physics * Check whether the Foot et al. calculations of mirror matter properties are consistent with all the experimental data as the authors claim * Extend the Foot et al. calculations to find, e.g. a non-gravitational effect of mirror matter in stellar physics, e.g. symbiotic stars (gravitational effects of dark matter are already well studied) * More info: http://adjani.astro.uni.torun.pl/cgi-bin/twiki/view/Cosmo/NonBaryonicDarkMatter#the_DAMA_NaI_detection_and_mirro
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Topic revision: r12 - 19 May 2009,
BoudRoukema
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