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Yi Mao, MIT

Constraining cosmological and gravitational parameters with upcoming astrophysical data. Yi Mao, MIT. Collaborators: Max Tegmark, Alan Guth, Matias Zaldarriaga, Matt McQuinn, Oliver Zahn, Tom Faulkner, Ted Bunn, Serkan Cabi . What do we learn in cosmology?. Yi Mao Fermilab seminar

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Yi Mao, MIT

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  1. Constraining cosmological and gravitational parameters with upcoming astrophysical data Yi Mao, MIT Collaborators: Max Tegmark, Alan Guth, Matias Zaldarriaga, Matt McQuinn, Oliver Zahn, Tom Faulkner, Ted Bunn, Serkan Cabi

  2. What do we learn in cosmology? Yi Mao Fermilab seminar January 23, 2008

  3. 0th order: Expansion H(z) a(t) k Yi Mao Fermilab seminar January 23, 2008

  4. dimmed Distant light is { distance Vs. z H(z) redshifted

  5. 1st order: Clustering Cl, P(k), … Yi Mao Fermilab seminar January 23, 2008

  6. CMB Z ~ 1089 Galaxy surveys z  1 Gravitational Lensing Supernovae Ia Ly-a forest

  7. But the best is yet to come Precision CMB (polarization, small scales), precision lensing …… and 21cm tomography Yi Mao Fermilab seminar January 23, 2008

  8. CMB Z ~ 1089 Galaxy surveys z  1 Gravitational Lensing Supernovae Ia Ly-a forest 21cm tomography

  9. Murchison Widefield Array (MWA) • Located in western Australia • 500 antennas; array diameters 1500m; • Measures z=6~12 Yi Mao Fermilab seminar January 23, 2008

  10. Other arrays • Square Kilometre Array (SKA) • Low Frequency Array (LOFAR) • 21cm Array (21CMA) Yi Mao Fermilab seminar January 23, 2008

  11. 21cm line from the Epoch of Reionization Yi Mao Fermilab seminar January 23, 2008

  12. 21cm Power spectrum • 21cm power spectrum is not isotropic because of redshift space distortion! Yi Mao Fermilab seminar January 23, 2008

  13. How accurately can 21cm tomography constrain cosmological parameters? Yi Mao Fermilab seminar January 23, 2008

  14. Yi Mao Fermilab seminar January 23, 2008

  15. K Yi Mao Fermilab seminar January 23, 2008 YM, Tegmark, McQuinn, Zaldarriaga & Zahn (2008)

  16. K Yi Mao Fermilab seminar January 23, 2008 YM, Tegmark, McQuinn, Zaldarriaga & Zahn (2008)

  17. Ionization power spectrum modeling Yi Mao Fermilab seminar January 23, 2008

  18. OPT Yi Mao Fermilab seminar January 23, 2008

  19. PESS Yi Mao Fermilab seminar January 23, 2008

  20. MID Yi Mao Fermilab seminar January 23, 2008 YM, Tegmark, McQuinn, Zaldarriaga & Zahn (2008)

  21. K Yi Mao Fermilab seminar January 23, 2008 YM, Tegmark, McQuinn, Zaldarriaga & Zahn (2008)

  22. Optimal array configuration Yi Mao Fermilab seminar January 23, 2008

  23. LOFAR MWA SKA OPT Size of total inner core MID Size of compact core Yi Mao Fermilab seminar January 23, 2008 YM, Tegmark, McQuinn, Zaldarriaga & Zahn (2008)

  24. MWA in OPT model Size of total inner core Size of compact core Yi Mao Fermilab seminar January 23, 2008 YM, Tegmark, McQuinn, Zaldarriaga & Zahn (2008)

  25. Future: 3D neutral hydrogen maps? Yi Mao Fermilab seminar January 23, 2008

  26. Testing gravity in a general framework Yi Mao Fermilab seminar January 23, 2008

  27. Generalize PPN • A general geometry is determined by metric (g) and connection (), both independent of each other. • Three quantities characterize the departure from Minkowski spacetime: Yi Mao Fermilab seminar January 23, 2008

  28. Generalized geometry family tree

  29. Constraining torsion Yi Mao Fermilab seminar January 23, 2008

  30. to linear order in m and a Parametrization of torsion around Earth

  31. Image from http://einstein.stanford.edu Constraining torsion with GPB

  32. Constraining torsion with GPB YM, Tegmark, Guth, Cabi (2006)

  33. Constraining f(R) gravity Yi Mao Fermilab seminar January 23, 2008

  34. Solar system constraints on f(R) Chameleon Faulkner, Tegmark, Bunn and YM (2007) Yi Mao Fermilab seminar January 23, 2008

  35. Constraints on cubic f(R) model Faulkner, Tegmark, Bunn and YM (2007) Yi Mao Fermilab seminar January 23, 2008

  36. Outlook • 3D HI mapping: direct view into the dark ages, precision constraints on cosmological parameters • Better understanding of the Epoch of Reionization • New tests of Einstein gravity on scales from the solar system to the cosmos • Common question for cosmology and gravitation: Dark energy = cosmological constant or modified gravity? Dark matter = new particles or TeVeS/MOND? Can GR (and standard cosmological model) be further tested? Yi Mao Fermilab seminar January 23, 2008

  37. Yi Mao Fermilab seminar January 23, 2008 Tegmark & Zaldarridaga, astro-ph/0207047+updates

  38. 21cm line • Spin temperature , where • Emission if Ts > Tcmb; absorption if Ts < Tcmb • Saturated when Ts >> Tcmb; arbitrarily large when Ts << Tcmb • The last factor makes the anisotropy! Yi Mao Fermilab seminar January 23, 2008

  39. Ts couplings • Absorption of CMB photons and stimulated emission • Collisions with H, e, p: Ts  Tk • Scattering of UV photons( the Wouthuysen-Field Effect): Ts  TLya Furlanetto, Oh & Briggs 2006 Yi Mao Fermilab seminar January 23, 2008

  40. Thermal histroy of IGM • zdec~150: compton heating. Tk = Tcmb before zdec; Tk~(1+z)2 after. • Z1: Ts = Tk before z1; Ts Tcmb after. • Zh: IGM Tk > Tcmb. • Zc: Wouthuysen-Field Effect couples Ts = Tk again. • Zr: reionization. Yi Mao Fermilab seminar January 23, 2008

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