MATTEO VIEL THE LYMAN- FOREST AS A COSMOLOGICAL PROBE Contents and structures of the Universe –...
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Transcript of MATTEO VIEL THE LYMAN- FOREST AS A COSMOLOGICAL PROBE Contents and structures of the Universe –...
MATTEO VIEL
THE LYMAN- FOREST AS A COSMOLOGICAL PROBE
Contents and structures of the Universe – La Thuile (ITALY), 19 March 2006
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
optical depth: ~ (IGM )1.6 T -0.7
GOAL: the primordial dark matter power spectrum from the observed flux spectrum
Tegmark & Zaldarriaga 2002
CMB physics z = 1100 dynamics
Lyphysics z < 6 dynamics + termodynamics
CMB + Lyman Long lever arm
Constrain spectral index and shape
Relation: P FLUX (k) - P MATTER (k) ??
Continuum fitting
Temperature, metals, noise
Maximum sensitivityof WMAP
RESULTS: POST- WMAP I LYMAN-
CMB
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
DM
STARS
GAS
NEUTRALHYDROGEN
m = 0.26 = 0.74 b=0.0463 H0 = 72 km/sec/Mpc - 60 Mpc/h 2x4003
GAS+DM 2.5 com. kpc/h softening length
GADGET –II code COSMOS computer – DAMTP (Cambridge)
DATA 27 high res z~2.125 QSO spectra 3000 QSO spectra z>2.2
THEORY: SIMULATIONS full hydro simulations `calibrated’ simulations
THEORY: METHOD 3D flux inversion 1D flux modelling
ADVANTAGES band power large redshift range
DRAWBACKS only z=2.1 (and 2.72) and 34 parameters modelling larger error bars
RESULTS no large running, scale invariant, `high’ power spectrum amplitude
LUQAS SDSS
Cosmological implications: combining the forest data with WMAP
SDSS Seljak et al. 2004
8= 0.93 ± 0.07 n=0.99 ± 0.03
8= 0.90 ± 0.03 n=0.98 ± 0.02 nrun = -0.003 ± 0.010 nrun=-0.033± 0.025
d ns/ d ln k
Viel, Weller, Haehnelt, MNRAS, 2004, 355,L23
Viel, Haehnelt, Springel, MNRAS, 2004, 354, 684
Seljak et al. 2004
In the Seljak analysis WMAP+Ly- constrains running three times better than WMAP+all the rest
SDSS Seljak et al. 2005
r < 0.45 (95% lim.)
r = 0.50 ± 0.30
T/S =
T/S
V = inflaton potential
Viel, Weller, Haehnelt, MNRAS, 2004, 355, L23
Inflation and dark energy
RESULTS: POST- WMAP II LYMAN-
CMB
WMAP I + Lyman- high-res WMAP III + Lyman- high-res
(credit: Antony Lewis)
Tension between WMAP3 and high resolution Lyman-a… 1.5 discrepancy
for SDSS it could be worse…
WMAP + LUQAS (high res) sample
New COSMOMC version with WMAP3 and Lyman- downloadble http://cosmologist.info/
8= 0.87 ± 0.04
n = 0.97 ± 0.04
n run (0.002 Mpc-1)= 0.005 ± 0.030
SDSS analysis Seljak et al. 2005, PRD
best fit amplitude from SDSS Lyman-a and WMAP1
is 3.5 off the new WMAP3 value
WMAP + SDSS flux power constraints
Best fit WMAP3
SMALL SCALE POWERWarm dark matter ? New observational results
from dwarf galaxies
Neutrinos ?
Isocurvature ?
Cosmological implications: Warm Dark Matter particles
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
k FS ~ 1.5 (m x/100eV) h/Mpc
In general if light gravitinos
Set by relativistic degrees of freedom at decoupling
Cosmological implications: WDM, gravitinos, neutrinos
Set limits on the scale ofSupersymmetry breaking
susy < 260 TeV
m WDM > 550 eV m grav< 16 eV > 2keV sterile neutrino
m (eV) < 0.95 (95 %C.L.) WMAP + 2dF + LY
WDM CWDM(gravitinos)
neutrinos
Can sterile neutrinos be the dark matter ?
Seljak et al. a-ph/0602430
Abazaijan 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
M sterile neutrino > 10 KeV 95 % C.L.
SDSS data only
8 = 0.91 ± 0.07n = 0.97 ± 0.04
Fitting SDSS data with GADGET-2 this is SDSS Ly- only !!
Isocurvature perturbations
Beltran, Garcia-Bellido, Lesgourgues, Viel, 2005, PRD, D72, 103515
:isocurvature fraction at k=0.05 Mpc-1
:quantifies correlation between ISO andADIABATIC modes
No iso Only iso
Fully correlated
Anti correlated
n iso=1.9 ± 1.0 95% C.L.
This is a model in agreement with WMAP3!
n ad=0.95n iso =3
n ad = 0.95n iso =2
SUMMARY
Cosmological parameters: Lyman- points to 8 = 0.9 n = 0.98 little running
substantial agreement between SDSS and LUQAS but SDSS has smaller error bars (factor ~ 2), due to the different theoretical modelling and wider range of redshift probed by SDSS Constraints on inflationary models, isocurvature, neutrinos and WDM have been obtained
From high res Lyman-: gravitinos + Dark matter and isocurvature Models are in agreement with WMAP3 Other measurements using Lyman- based on different methods give the same answer (Zaroubi et al. 2005, Viel & Haehnelt 2006), systematics are now in better control
Lyman- forest is a complementary measurement ofthe matter power spectrum and can be use to constrain cosmologytogether with the CMB – TENSION with WMAP 3
Mean flux
Effective optical depth
<F> = exp (- eff) Power spectrum of F/<F>
Low resolution SDSS like spectra
High resolution UVES like spectra
Thermal state
T = T0 ( 1 + )
Statistical SDSS errors on flux power
Thermal histories Flux power fractional differences
Numerical modelling: HPM simulations of the forest
Full hydro 200^3 part. HPM NGRID=600 HPM NGRID=400F
LUX
PO
WE
R
MV, Haehnelt, Springel, astro-ph/0504641
Hydro-simulations: what have we learnt?Many uncertainties which contribute more or less equally
(statistical error seems not to be an issue!)
Statistical error 4%
Systematic errors ~ 15 %
eff (z=2.125)=0.17 ± 0.02 8 %
eff (z=2.72) = 0.305 ± 0.030 7 %
= 1.3 ± 0.3 4 %
T0 = 15000 ± 10000 K 3 %
Method 5 %
Numerical simulations 8 %
Further uncertainties 5 %
ERRORS CONTRIBUTION TO FLUCT. AMPL.
Constraints on the evolution of the effective optical depth
8 = 0.7
8 = 1
8 = 0.925
Spergel et al. 2003
Peiris et al. 2003
Lyman- does most of the job in constraining running!!!
Lack of power in theRSI model: haloesform later. Contrastwith the large inferred(Yoshida et al. 2003)
The LUQAS sample
Kim, MV, Haehnelt, Carswell, Cristiani, 2004, MNRAS, 347, 355
Large sample Uves Qso Absorption Spectra(LP-UVES program P.I. J. Bergeron)
high resolution 0.05 Angstrom, high S/N > 50low redshift, <z>=2.25, z = 13.75
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