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Lyman-  Emission from The Intergalactic Medium

Lyman-  Emission from The Intergalactic Medium. Juna A. Kollmeier Theorsts: Zheng Zheng (IAS), David H. Weinberg (OSU) , Jordi Miralda-Escud é (ICREEA), Romeel Dav é (Steward) Neal Katz (U.Mass) Observers: Kurt Adelberger (McKenzie), Joe Hennawi (UCB),

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Lyman-  Emission from The Intergalactic Medium

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  1. Lyman- Emission from The Intergalactic Medium Juna A. Kollmeier Theorsts: Zheng Zheng (IAS), David H. Weinberg (OSU), Jordi Miralda-Escudé (ICREEA), Romeel Davé (Steward) Neal Katz (U.Mass) Observers: Kurt Adelberger (McKenzie), Joe Hennawi (UCB), Jason Prochaska (UCSC), Chuck Steidel (Caltech)

  2. Precision Cosmology Viel et al. 2006 WMAP team Hinshaw et al. 2003 Courtesy M. Tegmark

  3. Precision Galaxy Formation? Galaxy formation is far more complicated than cosmology!

  4. The Formation of Structure Courtesy of A. Kravtsov

  5. The IGM: Absorption Lyman-a forest powerful tool: traces mass and can be connected to cosmology! Courtesy of W. Sargent

  6. The IGM: Absorption 1d-Skewers 3d IGM

  7. 2P g 1S Why Lyman-a emission? • Look at the universe in Lyman-a eyes: FULL 3D INFORMATION! • Ionizations lead to recombinations: --> emission of Lyman-a photon Cosmic web in emission --> Galaxy/IGM connection!

  8. DETECTIONS! Nilsson et al. 2007 Steidel et al. 2000 Weidinger et al. 2004 Reuland et al. 2003 Francis et al. 2006

  9. Sources of Ly Emission • Fluorescence from uniform UVB • Fluorescence from local sources (internal and external) • Cooling radiation • Stars and quasars Predictions for these phenomena require Radiative Transfer!

  10. Frequency Diffusion Flux Frequency Shift Zheng & Miralda-Escude 2002, ApJ, 578

  11. Monte Carlo Radiative Transfer of Resonant Line Radiation From Simple Structures: Structures predicted by CDM: Zheng & Miralda-Escude 2002, ApJ, 578

  12. Monte Carlo Radiative Transfer of Resonant Line Radiation • Select observation direction • Select photon’s initial position in gas according to emissivity • Scatter photon according to velocity, temperature, density field • At each scattering, accumulate image/spectrum P(esc) P(esc) P(esc) Observation Direction

  13. A 2.5 Mpc region From z=2 SPH Simulation GAS DENSITY GAS TEMPERATURE

  14. Predicted Image + 2D Spectra From Kollmeier et al. in prep

  15. Fluorescence by Local Sources • Optically thick patches of IGM can be near bright sources (stars, QSOs) • The density combined with the high photoionization rate increases recombination rate • Careful balance!

  16. Effect of Quasar on X 1D distribution of neutral fraction in the plane of the QSO y=0

  17. Case I: Transverse From Adelberger, Steidel, Kollmeier, Reddy, ApJ, 2006, 637, 745

  18. Detection? To Quasar 40’’ From Adelberger, Steidel, Kollmeier, Reddy, ApJ, 2006, 637, 745

  19. Model Predictions

  20. Match? • Simultaneous match of high surface brightness and large absorber size not successful • Improvements to model? Add heating from QSO does increase SB (but why would this not evaporate the cloud). Ly not from QSO (but why such good agreement with “mirror”)? • Something else?

  21. Case II: Line of Sight

  22. Detection? From Hennawi, Prochaska, Kollmeier & Zheng in prep

  23. Model Predictions QSO Behind DLA Total Flux (predicted) = 5.33 x 10-20 erg/s/cm2 Total Flux (observed) = 4.3 x 10-16 erg/s/cm2

  24. For the Future Integral field units on big telescopes could produce this: Once you have 1 Lyman Limit System you have many!

  25. Summary • IGM is rife with information on structure formation! • Monte Carlo radiative transfer of Lya now included in cosmological simulations Many applications for studying galaxy formation at high and low redshift • fluorescence of Lyman limit systems by UVB • fluorescence of DLAs by local sources • cooling radiation from galaxy formation in action • Lya emitters • sources of reionization • Required to interpret programs underway • Helpful for designing future surveys

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