MATTEO VIEL

THE LYMAN- FOREST: A UNIQUE TOOL FOR COSMOLOGY

Bernard’s cosmic stories – Valencia, 26 June 2006

Trieste

Dark matter Gas

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)

3000 LOW RESOLUTION LOW S/N 30 HIGH RESOLUTION HIGH S/NSDSS LUQAS

SDSS vs LUQAS

McDonald et al. astro-ph/0405013 Kim, Viel et al. 2004, MNRAS, 347, 355

Viel , Haehnelt, Lewis, 2006, MNRAS in press, a-ph/0604310

Ly- + WMAP1 Ly- + WMAP3

VHS(LUQAS): high res Ly-a from Viel, Haehnelt, Springel 2004SDSS: low res Ly-a from McDonald et al. 2005

Lyman- forest + CMB - I

VHS+WMAP1

SDSS+WMAP1

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

SDSS: McDonald et al. 2005, Seljak et al. 2005 Hydro Particle Mesh simulationsSDSS-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; p0) + i=1,N P F (k, z; pi) (pi - pi0)

pi

p = p0

Lyman- forest + CMB - II

Best fit

Flux power

p: astro and cosmo param.

Numerical modelling: HydroParticleMesh simulations of the forest

Full hydro 200^3 part. HPM NGRID=600 HPM NGRID=400F

LUX

PO

WE

R

MV, Haehnelt, Springel 2006

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

31,2

3

RESULTS LYMAN-Warm dark matter

Lyman- and Warm Dark Matter - I

CDMWDM 0.5 keV

30 comoving Mpc/h z=3

MV, Lesgourgues, Haehnelt, Matarrese, Riotto, PRD, 2005, 71, 063534

k FS ~ 5 Tv/Tx (m x/1keV) Mpc-1

In general

Set by relativistic degrees of freedom at decoupling

See Bode, Ostriker, Turok 2001 Abazajian, Fuller, Patel 2001

m WDM > 550 eV > 2keV sterile neutrino

WDM CWDM(gravitinos)

neutrinos

Lyman- and Warm Dark Matter - I

Viel et al. 2005 from high-resz=2.1 sample

Seljak et al. 2006, astro-ph/0602430

m WDM > 2 keV > 14 keV sterile neutrino

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 p

ow

er

2 < m (KeV) < 8 m (KeV) > 14

Increasing z

- Pulsar kick (Kusenko et al….)

For sterile neutrino models the parameterSpace is described by m and mixing angle)

Mass

of

steri

le n

eutr

ino (

keV

)

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

Perseus Cluster (Jeremy Sanders)

Decaying channel into photons and active neutrinos line with E=ms/2 (X-band)

5.66 keV

SUMMARY

Lyman- forest is a complementary measurement ofthe matter power spectrum and can be use to constrain cosmologytogether 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 ± 0.01SDSS+VHS: 8=0.78 ± 0.05, n = 0.96 ± 0.02 (not constraining anymore)

Tight constraints on neutrino mass fraction, tensor to scalar ratioand running – if you believe the data

Sterile neutrino probably ruled out in the standard production mechanism