lyman- emission from the intergalactic medium
DESCRIPTION
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), - PowerPoint PPT PresentationTRANSCRIPT
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)
Precision Cosmology
Courtesy M. Tegmark
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Hinshaw et al. 2003
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Viel et al. 2006 WMAP team
Precision Galaxy Formation?
Galaxy formation is far more complicated than
cosmology!
The Formation of Structure
Courtesy of A. Kravtsov
The IGM: Absorption
Courtesy of W. Sargent
Lyman- forest powerful tool: traces mass and can be connected to cosmology!
The IGM: Absorption
1d-Skewers 3d IGM
Why Lyman- emission?• Look at the universe in Lyman- eyes:
FULL 3D INFORMATION!
• Ionizations lead to recombinations:
--> emission of Lyman- photon
2P
1S
Cosmic web in emission --> Galaxy/IGM connection!
DETECTIONS!
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Reuland et al. 2003
Steidel et al. 2000
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Nilsson et al. 2007 QuickTime™ and a
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Weidinger et al. 2004
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Francis et al. 2006
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!
Frequency Diffusion
Zheng & Miralda-Escude 2002, ApJ, 578
Flu
x
Frequency Shift
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Monte Carlo Radiative Transfer of Resonant Line Radiation
Zheng & Miralda-Escude 2002, ApJ, 578
From Simple Structures: Structures predicted by CDM:
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
Observation Direction
P(esc)
P(esc)P(esc)
A 2.5 Mpc region From z=2 SPH Simulation
GAS DENSITY GAS TEMPERATURE
Predicted Image + 2D Spectra
From Kollmeier et al. in prep
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!
Effect of Quasar on X
1D distribution of neutral fraction in the plane of the QSO
y=0
Case I: Transverse
From Adelberger, Steidel, Kollmeier, Reddy, ApJ, 2006, 637, 745
Detection?
From Adelberger, Steidel, Kollmeier, Reddy, ApJ, 2006, 637, 745
To Quasar
40’’
Model Predictions
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?
Case II: Line of Sight
Detection?
From Hennawi, Prochaska, Kollmeier & Zheng in prep
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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
For the Future
Integral field units on big telescopes could produce this:
Once you have 1 Lyman Limit System you have many!
Summary• IGM is rife with information on structure formation!• Monte Carlo radiative transfer of Ly 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– Ly emitters– sources of reionization
• Required to interpret programs underway• Helpful for designing future surveys