1. MATTEO VIEL THE LYMAN-  FOREST: A UNIQUE TOOL FOR COSMOLOGY Bernard’s cosmic stories – Valencia, 26 June 2006 Trieste Dark matter Gas

2. 80 % of the baryons at z=3 are in the Lyman-  forest baryons as tracer of the dark matter density field  IGM ~  DM at scales larger than the Jeans length ~ 1 com Mpc  ~ (  IGM ) 1.6 T -0.7 Bi & Davidsen (1997), Rauch (1998)

3. 3000 LOW RESOLUTION LOW S/N 30 HIGH RESOLUTION HIGH S/N SDSSLUQAS SDSS vs LUQAS McDonald et al. astro-ph/0405013 Kim, Viel et al. 2004, MNRAS, 347, 355

4. Viel, Haehnelt, Lewis, 2006, MNRAS in press, a-ph/0604310 Ly-  + WMAP1 Ly-  + WMAP3 VHS(LUQAS): high res Ly-a from Viel, Haehnelt, Springel 2004 SDSS: low res Ly-a from McDonald et al. 2005 Lyman-  forest + CMB - I VHS+WMAP1 SDSS+WMAP1

5. Lyman-  forest + CMB - II With WMAP3 like-priors:  M = 0.235 ± 0.035 H 0 = 73 ± 3 km/s/Mpc SDSS amplitude and “slope” are 2  away WMAP3

6. SDSS: McDonald et al. 2005, Seljak et al. 2005 Hydro Particle Mesh simulations SDSS-d: Viel & Haehnelt 2006: analysis of SDSS flux power using flux derivatives and full hydrodynamical simulations P F (k, z; p) = P F (k, z; p 0 ) +   i=1,N  P F (k, z; p i ) (p i - p i 0 )  p i p = p 0 Lyman-  forest + CMB - II Best fit Flux power p: astro and cosmo param.

7. Numerical modelling: HydroParticleMesh simulations of the forest Full hydro 200^3 part. HPM NGRID=600 HPM NGRID=400 FLUX POWER MV, Haehnelt, Springel 2006

8. Lyman-  forest + CMB - III Seljak, Slosar. McDonald, 2006, a-ph/0604335  m (eV) < 0.17 (95 %C.L.) r < 0.22 (95 % C.L.) running = -0.020 ± 0.12 CMB + SN + SDSS gal+ SDSS Ly-   m (eV) < 0.68 (95 %C.L.) r < 0.55 (95 % C.L.) running = -0.055 ± 0.03 WMAP3 only r n normal inverted 1 2 3 1,2 3

9. RESULTS LYMAN-   Warm dark matter

10. Lyman-  and Warm Dark Matter - I  CDM WDM 0.5 keV 30 comoving Mpc/h z=3 MV, Lesgourgues, Haehnelt, Matarrese, Riotto, PRD, 2005, 71, 063534 k FS ~ 5 T v /T x (m x /1keV) Mpc -1 In general Set by relativistic degrees of freedom at decoupling See Bode, Ostriker, Turok 2001 Abazajian, Fuller, Patel 2001

11. m WDM > 550 eV > 2keV sterile neutrino WDM  CWDM (gravitinos) neutrinos Lyman-  and Warm Dark Matter - I Viel et al. 2005 from high-res z=2.1 sample Seljak et al. 2006, astro-ph/0602430 m WDM > 2 keV > 14 keV sterile neutrino

12. Ly  -WDM II : Can sterile neutrinos be the dark matter ? Seljak et al. a-ph/0602430 Abazajian a-ph/0512631 Biermann & Kusenko PRL 2006,96, 091301 - Molecular hydrogen and reionization - X-Ray backgrounds - Flux power evolution Flux power 2 < m (KeV) < 8 m (KeV) > 14 Increasing z - Pulsar kick (Kusenko et al….) For sterile neutrino models the parameter Space is described by m and  mixing angle) Mass of sterile neutrino (keV)

13. Ly  -WDM III: analysis with flux derivatives z < 4.2 z < 3.8 z < 3.2 MV, Lesgourgues, Haehnelt, Matarrese, Riotto, 2006, astro-ph/0605706

14. Perseus Cluster (Jeremy Sanders) Decaying channel into photons and active neutrinos line with E=m s /2 (X-band) 5.66 keV

15. SUMMARY Lyman-  forest is a complementary measurement of the matter power spectrum and can be use to constrain cosmology together with the CMB SDSS+WMAP3 :  8 =0.86 ± 0.03, n=0.96 ± 0.02 SDSS-d+WMAP3:  8 =0.80 ± 0.04, n=0.96 ± 0.01 SDSS+VHS:  8 =0.78 ± 0.05, n = 0.96 ± 0.02 (not constraining anymore) Tight constraints on neutrino mass fraction, tensor to scalar ratio and running – if you believe the data Sterile neutrino probably ruled out in the standard production mechanism