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Investigating the ionisation and metal enrichment history of the Intergalactic Medium using simulations and observational data.
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Tom Theuns Institute for Computational Cosmology, Durham, UK Department of Physics, Antwerp, Belgium Simulating the ionisation and metal enrichment history of the Intergalactic Medium
The LCDM paradigm WMAP et al + 2dF/Sloan et al Tom Theuns: IGM ionisation and enrichment
How to go from to Tom Theuns: IGM ionisation and enrichment
Semi-analytic galaxy formation and the large-scale galaxy distribution Durham incarnation Tom Theuns: IGM ionisation and enrichment
Distribution of galaxies in 2dF GRS Tom Theuns: IGM ionisation and enrichment
Distribution of galaxies in simulated 2dF GRS Tom Theuns: IGM ionisation and enrichment
Simulations and the starformation history Springel & Hernquist 2003 Tom Theuns: IGM ionisation and enrichment
Simulations and stellar archaeology Single galaxy and the importance of feedback Stars Gas Okamoto et al 05 Tom Theuns: IGM ionisation and enrichment
Stellar Archeology: Harris & Zaritsky Tom Theuns: IGM ionisation and enrichment
The importance of “feedback”: galaxy-wide winds? M82 Springel Tom Theuns: IGM ionisation and enrichment
More evidence for super winds? Sauron observations of a Ly a ”blob” at z=3 Wilman et al 05 Tom Theuns: IGM ionisation and enrichment
Lyman a profile suggests presence of “sheet” of neutral gas, expelled by an earlier superwind phase Wilman et al 05 Tom Theuns: IGM ionisation and enrichment
Absorption lines of several (low-ionization state) transitions are off-set from the velocity of the stars by many 100s of km/s in cB58, a Lyman-break gal@z=3 Pettini et al Tom Theuns: IGM ionisation and enrichment
A new ISM multi-phase implementation: use sticky particles to represent molecular clouds (with Craig Booth) M33 (UV) M33 (Visual ) Tom Theuns: IGM ionisation and enrichment
Sticky particle scheme: (Craig Booth) • Thermal instability leads to cloud formation (McKee & Ostriker) • Small clouds coagulate to make more massive clouds • GMCs collapse after 10Myr, converting 10% of mass into stars • Stellar winds and Sne explosions destroy GMC (feedback) • Hot gas evaporates small clouds Nearly resolution independent! Tom Theuns: IGM ionisation and enrichment
Star formation in a closed box F SFR T[K] Time Tom Theuns: IGM ionisation and enrichment
… and in M33 Position of clouds formed in a collapsing rotating sphere Tom Theuns: IGM ionisation and enrichment
Feedback from AGN X-ray observations of the Perseus galaxy clusters show hot cavities, plausibly inflated by AGN Chandra Tom Theuns: IGM ionisation and enrichment
Buoyant bubbles from an AGN heating the gas and quench cooling (flow). Flash/AMR Tom Theuns: IGM ionisation and enrichment Della Vecchia
Flash AMR code at Durham: • Radiative transfer (Crash) • Star formation and feedback • Gravity (fftw version) Tom Theuns: IGM ionisation and enrichment
Investigate radiative transfer effects Maselli et al Tom Theuns: IGM ionisation and enrichment
X-ray preheating from early black holes Kuhlen & Madau Tom Theuns: IGM ionisation and enrichment
Simulated spectra look very similar to the data Mock versus Keck spectrum: which is which? Theuns Tom Theuns: IGM ionisation and enrichment
Pixel Optical Depth Method Simulations look very realistic: use them to estimate contamination in interpreting metal optical depths, and to compute other sources of bias. Schaye et al, Aguirre et al. Tom Theuns: IGM ionisation and enrichment
Metals (C IV) found to low densities. No obvious evolution with redshift. Galactic winds? Pop III Stars? Abundance redshift density Schaye et al 2003 Tom Theuns: IGM ionisation and enrichment
Can feedback implementation explain observed metals? Simulation with metal enrichment due to galactic winds appears to reproduce the observed CIV-HI scatter Theuns et al 2001 Tom Theuns: IGM ionisation and enrichment
The winds generated have little effect on the Lya forest Tom Theuns: IGM ionisation and enrichment
But do reasonably well in reproducing the C IV lines Tom Theuns: IGM ionisation and enrichment
NCarbon NHydrogen Tom Theuns: IGM ionisation and enrichment
In simulations, there are a lot of metals in hot gas. Pixel Optical Depth analysis: C III/ C IV C IV Are the metals in the simulations too hot? Aguirre et al ‘05 Tom Theuns: IGM ionisation and enrichment
Using QSO sightlines to probe density structure around galaxies and QSOs Tom Theuns: IGM ionisation and enrichment
Adelberger et al 03 Tom Theuns: IGM ionisation and enrichment
Density structure around QSOs and the proximity effect Fraction of pixels with given scaled optical depth, t = t0(z0) (1+z)a Rollinde et al 05 Tom Theuns: IGM ionisation and enrichment
Rollinde et al 05 Tom Theuns: IGM ionisation and enrichment
Lya forest becomes very dense at z>6: end of reionisation? Tom Theuns: IGM ionisation and enrichment
What is evolution of ionizing background? Haardt & Madau ‘96 Tom Theuns: IGM ionisation and enrichment
Galaxies must dominated G at z > 5 Estimate of G from simulations (diamonds) and inferrred from sources (triangles, squares) Bolton et al ’04 Jena et al ‘04 Tom Theuns: IGM ionisation and enrichment
Bernardi et al 02 Theuns et al 02 Evidence for He II reionisation from Sloan Tom Theuns: IGM ionisation and enrichment
IGM temperature as function of redshift. Schaye et al. Tom Theuns: IGM ionisation and enrichment
If no other heat sources, HI reionization late? Theuns et al. Tom Theuns: IGM ionisation and enrichment
Does reionization affect galaxy formation? Yes: Barkana & Loeb Tom Theuns: IGM ionisation and enrichment
Does reionization affect galaxy formation? No: Benson et al Tom Theuns: IGM ionisation and enrichment
Summary • Feedback • Reionisation • Ionising background. • First objects • Importance of AGN? Thank you Tom Theuns: IGM ionisation and enrichment
2. Numerical simulations: c) photo-ionisation Tom Theuns: IGM ionisation and enrichment