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Galaxies and the Intergalactic Medium

Explore the connection between galaxies and the intergalactic medium with Tom Theuns' research at the UK and Belgium institutes. Discover theories, simulations, and observations shedding light on galaxy formation and stellar archaeology.

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Galaxies and the Intergalactic Medium

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  1. Tom Theuns Institute for Computational Cosmology, Durham, UK Department of Physics, Antwerp, Belgium Galaxies and the Intergalactic Medium

  2. The LCDM paradigm WMAP et al + 2dF/Sloan et al Tom Theuns: Galaxies and the IGM

  3. How to go from to Tom Theuns: Galaxies and the IGM

  4. 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

  5. Semi-analytic galaxy formation and the large-scale galaxy distribution Durham incarnation Tom Theuns: Galaxies and the IGM

  6. Distribution of galaxies in 2dF GRS Tom Theuns: Galaxies and the IGM

  7. Distribution of galaxies in simulated 2dF GRS Tom Theuns: Galaxies and the IGM

  8. Simulations and the starformation history Springel & Hernquist 2003 Tom Theuns: Galaxies and the IGM

  9. Tom Theuns: Galaxies and the IGM

  10. Simulations and stellar archaeology Single galaxy and the importance of feedback Stars Gas Okamoto et al 05 Tom Theuns: Galaxies and the IGM

  11. Stellar Archaeology Stanway et al. Tom Theuns: Galaxies and the IGM

  12. Stellar Archeology: Harris & Zaritsky Tom Theuns: Galaxies and the IGM

  13. Tom Theuns: Galaxies and the IGM

  14. The importance of “feedback”: galaxy-wide winds? M82 Springel Tom Theuns: Galaxies and the IGM

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. Tom Theuns: Galaxies and the IGM

  21. Star formation in a closed box F SFR T[K] Time Tom Theuns: Galaxies and the IGM

  22. Tom Theuns: Galaxies and the IGM

  23. … and in M33 Position of clouds formed in a collapsing rotating sphere Tom Theuns: Galaxies and the IGM

  24. Scheme is similar to quiescent SF scheme of Efstathiou 00 Tom Theuns: Galaxies and the IGM

  25. 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

  26. Buoyant bubbles from an AGN heating the gas and quench cooling (flow). Flash/AMR Tom Theuns: Galaxies and the IGM Della Vecchia

  27. Tom Theuns: Galaxies and the IGM

  28. 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

  29. A QSO sightline often passes close to a galaxy. Tom Theuns: Galaxies and the IGM

  30. Keck/HiRes and VLT/UVES have revolutionised observations of the IGM. Tom Theuns: Galaxies and the IGM

  31. Analysing a QSO spectrum: a simple example Tom Theuns: Galaxies and the IGM

  32. The widths of the lines depend on structure (Hubble broadening) and temperature Tom Theuns: Galaxies and the IGM

  33. Simulated spectra look very similar to the data Mock versus Keck spectrum: which is which? Theuns Tom Theuns: Galaxies and the IGM

  34. 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

  35. 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

  36. 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

  37. The winds generated have little effect on the Lya forest Tom Theuns: Galaxies and the IGM

  38. But do reasonably well in reproducing the C IV lines Tom Theuns: Galaxies and the IGM

  39. NCarbon NHydrogen Tom Theuns: Galaxies and the IGM

  40. 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

  41. Using QSO sightlines to probe density structure around galaxies and QSOs Tom Theuns: Galaxies and the IGM

  42. Adelber et al 03 Tom Theuns: Galaxies and the IGM

  43. 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

  44. Rollinde et al 05 Tom Theuns: Galaxies and the IGM

  45. Lya forest becomes very dense at z>6: end of reionisation? Tom Theuns: Galaxies and the IGM

  46. What is evolution of ionizing background? Haardt & Madau ‘96 Tom Theuns: Galaxies and the IGM

  47. 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

  48. Does reionization affect galaxy formation? Yes: Barkana & Loeb Tom Theuns: Galaxies and the IGM

  49. Does reionization affect galaxy formation? No: Benson et al Tom Theuns: Galaxies and the IGM

  50. 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

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