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Tom Theuns Institute for Computational Cosmology, Durham, UK Department of Physics, Antwerp, Belgium. Galaxies and the Intergalactic Medium. The L CDM paradigm. WMAP et al + 2dF/Sloan et al. How to go from. to.
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Tom Theuns Institute for Computational Cosmology, Durham, UK Department of Physics, Antwerp, Belgium Galaxies and the Intergalactic Medium
The LCDM paradigm WMAP et al + 2dF/Sloan et al Tom Theuns: Galaxies and the IGM
How to go from to Tom Theuns: Galaxies and the IGM
Use observations of Intergalactic Medium to better understand galaxy formation process • Theory • semi-analytical • simulations • Observations of galaxies • fossil evidence (stellar archaeology) • winds/feedback. Supernovae vs AGN • starformation history • Observations of the IGM • Metals • Reionization Tom Theuns: Galaxies and the IGM
Semi-analytic galaxy formation and the large-scale galaxy distribution Durham incarnation Tom Theuns: Galaxies and the IGM
Distribution of galaxies in 2dF GRS Tom Theuns: Galaxies and the IGM
Distribution of galaxies in simulated 2dF GRS Tom Theuns: Galaxies and the IGM
Simulations and the starformation history Springel & Hernquist 2003 Tom Theuns: Galaxies and the IGM
Simulations and stellar archaeology Single galaxy and the importance of feedback Stars Gas Okamoto et al 05 Tom Theuns: Galaxies and the IGM
Stellar Archaeology Stanway et al. Tom Theuns: Galaxies and the IGM
Stellar Archeology: Harris & Zaritsky Tom Theuns: Galaxies and the IGM
The importance of “feedback”: galaxy-wide winds? M82 Springel Tom Theuns: Galaxies and the IGM
More evidence for super winds? Sauron observations of a Ly a ”blob” at z=3 Wilman et al 05 Tom Theuns: Galaxies and the IGM
Lyman a profile suggests presence of “sheet” of neutral gas, expelled by an earlier superwind phase Wilman et al 05 Tom Theuns: Galaxies and the IGM
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: Galaxies and the IGM
A new ISM multi-phase implementation: use sticky particles to represent molecular clouds (with Craig Booth) M33 (UV) M33 (Visual + CO) Tom Theuns: Galaxies and the IGM
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: Galaxies and the IGM
Star formation in a closed box F SFR T[K] Time Tom Theuns: Galaxies and the IGM
… and in M33 Position of clouds formed in a collapsing rotating sphere Tom Theuns: Galaxies and the IGM
Scheme is similar to quiescent SF scheme of Efstathiou 00 Tom Theuns: Galaxies and the IGM
Feedback from AGN X-ray observations of the Perseus galaxy clusters show hot cavities, plausibly inflated by AGN Chandra Tom Theuns: Galaxies and the IGM
Buoyant bubbles from an AGN heating the gas and quench cooling (flow). Flash/AMR Tom Theuns: Galaxies and the IGM Della Vecchia
How can observations of the intergalactic medium help us in our understanding of galaxy formation? Production of ionizing photons Production of metals Tom Theuns: Galaxies and the IGM
A QSO sightline often passes close to a galaxy. Tom Theuns: Galaxies and the IGM
Keck/HiRes and VLT/UVES have revolutionised observations of the IGM. Tom Theuns: Galaxies and the IGM
Analysing a QSO spectrum: a simple example Tom Theuns: Galaxies and the IGM
The widths of the lines depend on structure (Hubble broadening) and temperature Tom Theuns: Galaxies and the IGM
Simulated spectra look very similar to the data Mock versus Keck spectrum: which is which? Theuns Tom Theuns: Galaxies and the IGM
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: Galaxies and the IGM
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: Galaxies and the IGM
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: Galaxies and the IGM
The winds generated have little effect on the Lya forest Tom Theuns: Galaxies and the IGM
But do reasonably well in reproducing the C IV lines Tom Theuns: Galaxies and the IGM
NCarbon NHydrogen Tom Theuns: Galaxies and the IGM
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: Galaxies and the IGM
Using QSO sightlines to probe density structure around galaxies and QSOs Tom Theuns: Galaxies and the IGM
Adelber et al 03 Tom Theuns: Galaxies and the IGM
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: Galaxies and the IGM
Rollinde et al 05 Tom Theuns: Galaxies and the IGM
Lya forest becomes very dense at z>6: end of reionisation? Tom Theuns: Galaxies and the IGM
What is evolution of ionizing background? Haardt & Madau ‘96 Tom Theuns: Galaxies and the IGM
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: Galaxies and the IGM
Does reionization affect galaxy formation? Yes: Barkana & Loeb Tom Theuns: Galaxies and the IGM
Does reionization affect galaxy formation? No: Benson et al Tom Theuns: Galaxies and the IGM
Summary • Most simulations and semi-analytics require strong feedback • Such feedback is seen. But how common? • Can multi-phase medium decrease the importance of feedback? • Can the observed metals be produced by the observed galaxies? • (dwarfs/more massive gals/pop III stars?) • Importance of AGN? Thank you Tom Theuns: Galaxies and the IGM