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Dark Matter in the Universe

arnold.hanslmeier@uni-graz.at. Dark Matter in the Universe. The Universe. What do we know about it age: 14.6 billion years Evolved from Big Bang chemical composition Structures in the universe galaxy clusters galaxies voids. Separation of forces. gravity strong force weak force.

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Dark Matter in the Universe

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  1. arnold.hanslmeier@uni-graz.at Dark Matter in theUniverse

  2. The Universe • What do we know about it • age: 14.6 billion years • Evolved from Big Bang • chemical composition • Structures in the universe • galaxy clusters • galaxies • voids

  3. Separation offorces • gravity • strong force • weak force

  4. whatcausesinteraction? • gravity • electromagnetism • weakforce • strong force

  5. Someparticlephysics • Baryons: composedofthreequarks • Mesons: composedofonequarkandoneantiquark • Baryons andmesons: hadrons • Hadronsarecomposedofquarksstronginteraction • Leptons: noquarks, no strong interaction proton; the only long living hadron, t=1031s; measure for p decay= test for GUT

  6. Higgsparticle, higgsfield • mass=interaction of a particle • In empty space, the Higgs field has an amplitude different from zero; i.e., a non-zero vacuum expectation value. • The existence of this non-zero vacuum expectation plays a fundamental role: it gives mass to every elementary particle which has mass, including the Higgs boson itself.

  7. Galaxies Clusters what causes structure in the universe?

  8. Das galaktische Zentrum

  9. La voielactee

  10. The solar neighborhood

  11. Galaxis 200-400 109 Sterne Durchm.: 100 000 Lj Rotation: Ort der Sonne etwa 200 Mill Jahre

  12. Determination ofthemassof a galaxy Star Galactic center centrigual force attraction

  13. Solarsystem… Merkury: 88 days Earth: 1 year Jupiter: 11,6 years…

  14. Galacticrotationcurve v (R)

  15. Kepler

  16. Rotation of a galaxy Rotation curve of NGC 3198 merde

  17. Gravity lensing

  18. Composite image of the Bullet cluster shows distribution of ordinary matter, inferred from X-ray emissions, in red and total mass, inferred from gravitational lensing, in blue.

  19. propertiesofdark matter • undetectable by radiation • detectable only by gravitation • rotation of galaxies • orbital velocities of galaxies in cluster of galaxies • gravitational lensing • temperature distribution of hot gas in galaxies and clusters of galaxies

  20. whatisdark matter madeof • majority: non baryonic • non baryonic matter • neutrinos • axions • supersymmetric particles • does not contribute to the formation of elements in the cosmos

  21. non baryonic matter • hdm hot dark matter: massive neutrinos • cdm cold dark matter: will lead to a bottom up formation of structure in the universe; neutralino • wdm warm dark matter

  22. Neutralinos • big bang: neutralino halos • mass of Earth, size equal to the solar system • can be detected: • disturb Oort cloud  cometary showers • produce gamma ray bursts when colliding • more probable near galactic center

  23. baryonic matter • composedofbaryons • protons • neutrons • candidatesforbaryonicdark matter • MACHOs: massive astropnomicalcompacthaloobjects • browndwarfs (M<0.08 MSun • amountcanbecalculatedfrom • big bang nucelosynthesis • cosmicmicrowavebackground

  24. MACHOS • Detect: gravity bends light • MACHO may be detected if it pass in front of a star or nearby a star;  brightening of the star • candidates for MACHOS • black holes • neutron stars • black dwarfs

  25. WIMPS weaklyinteracting massive particles • interact through weak force and gravity • do not interact through electromagnetism • large mass, slow moving, cold particles • could interact with the Sun, produce high energy neutrinos

  26. CDMS cryogenicdark matter search

  27. RAMBOs Robust associations of massive baryonic objects • dark cluster made of • white dwarfs • brown dwarfs • radii: 1 pc … 15 pc

  28. supersymmetry, susy • In particle physics, supersymmetry (often abbreviated SUSY) is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are known as superpartners. • In a theory with unbroken supersymmetry, for every type of boson there exists a corresponding type of fermion with the same mass and internal quantum numbers, and vice-versa.

  29. Λ CDM Model ofCosmology I • Λ cosmological constant  associated with a vacuum energy or dark energy • explains the current accelerating expansion of space against the attractive (collapsing) effects of gravity. ΩΛ, which is interpreted as the fraction of the total mass-energy density of a flat universe that is attributed to dark energy. • Currently, about 74% of the energy density of the present universe is estimated to be dark energy.

  30. Λ CDM Model ofCosmology II • CDM cold dark matter • dark matter is described as • cold (non relativistic) • collisionless (only gravity forces) • 22% of the mass-energy density of the universe

  31. quantum chromodynamics describes strong interaction

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