Ofer Lahav University College London

Ofer Lahav University College London

(I) Neutrino Masses from LSS

(I) Neutrino Masses from the CMB

(III) The Dark Energy Survey

Concordance Cosmology

SN Ia CMB LSS – Baryonic

Oscillations Cluster counts Weak Lensing Integrated Sachs Wolfe

Physical effects: * Geometry * Growth of Structure

Massive Neutrinos and Cosmology

* Why bother? – absolute mass, effect on other parameters * Brief history of ‘Hot Dark Matter’

* Limits on the total Neutrino mass from cosmology within CDM M < 1 eV * Mixed Dark Matter? * Non-linear power spectrum and biasing – halo model

* Combined cosmological observations and laboratory experiments

Brief History of ‘Hot Dark Matter’

* 1970s : Top-down scenario with massive neutrinos (HDM) – Zeldovich Pancakes

* 1980s: HDM - Problems with structure formation

* 1990s: Mixed CDM (80%) + HDM (20% )

* 2000s: Baryons (4%) + CDM (26%) +Lambda (70%): But now we know HDM exists! How much?

Globalisation and the New Cosmology

How is the New Cosmology affected by Globalisation?

Recall the Cold War era: Hot Dark Matter/top-down (East) vs. Cold Dark Matter/bottom-up (West)

Is the agreement on the `concordance model’ a product of Globalisation?

OL, astro-ph/0610713

From Great Walls to Neutrino Masses

Neutrinos decoupled when they were still relativistic, hence they wiped out structure on small scales

k > knr = 0.026 (m/1 eV)1/2 m1/2 h/Mpc

Colombi, Dodelson, & Widrow 1995

WDMCDM+HDM

CDM

Massive neutrinos mimica smaller source term

Neutrino properties

TheThe number of neutrino species Nnumber of neutrino species N affects affects

the expansion rate of the universe, hence BBN.the expansion rate of the universe, hence BBN.

BBN constraints BBN constraints NN between between 1.7 and 31.7 and 3 (95% CL) (95% CL)

(e.g. Barger et al. 2003).(e.g. Barger et al. 2003).

From CMB+LSS+SN Ia, From CMB+LSS+SN Ia, NN =4.2 =4.2+1.2+1.2-1.7-1.7 (95% CL)(95% CL)

(Hannestad 2005)(Hannestad 2005)

We shall assume NWe shall assume N=3=3

Electron, muon and tau neutrinos neutrinos Eigen states Eigen states m1, m2, m3

neutrinos per cmneutrinos per cm33

hheVeV

Neutrino Mass Hierarchy

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Absolute Masses of Neutrinos

Based onmeasuredsquared mass differences from solar and atmosphericoscillations

Assuming

m1 < m2 < m3

E & L, NJP 05

What could cosmic probes tell us about Neutrinos and

Dark Energy?

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The Growth factor: degeneracy of Neutrinos Mass and Dark Energy

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Kiakotou, Elgaroy, OL

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Kiakotou, Elgaroy, OL 2007, astro-ph 0709.0253

P(k)/P(k) P(k)/P(k) = -8 = -8 mm

Not valid on useful Not valid on useful

scales!scales!

Weighing Neutrinos with 2dFGRS

Free streaming effect: /m< 0.13

Total mass M< 1.8 eV

(Oscillations) (2dF)

a Four-Component Universe ?

Elgaroy , Lahav & 2dFGRS team, astro-ph/0204152 , PRL

= 0.05

0.01

0.00

What do we mean by ‘systematic uncertainties’?

• Cosmological (parameters and priors)

• Astrophysical (e.g. Galaxy biasing)

• Instrumental (e.g. ‘seeing’)

Degeneracy of neutrino mass

n= 0.9

n= 1.1

n=1.0

Prior 0< m<0.5

Biasing vs. neutrino mass

Elgaroy & Lahav , JCAP, astro-ph/030389

---- SAM for

L>0.75 L*

Pg(k) = b2(k) Pm(k)

b(k) = a log(k) + c a

Total neutrino mass

Weak Lensing is promising

Abazajian & Dodelson (2003)

also Hannestad et al. 2006

Non-linear P(k) with massive neutrinosAbazajian et al. (astro-ph/0411552) modeled the effects of neutrino infall into CDM halos and incorporated it in the halo model. The effect is small: P(k)/P(k) » 1%

at k » 0.5 h/Mpc for M » 1 eV

Future work : high-resolution simulations with CDM, baryons and neutrinos

CMB with massive

E&L 2004E&L 2004M =0.3, 0.9, 1.5, 6.0 eVFixed cdm = 0.26

Neutrinos masses and the CMB If znr > zrec h2 > 0.017 (i.e. M > 1.6 eV) Then neutrinos behave like matter - this defines a critical value in CMB features * Ichikawa et al. (2004 ) from WMAP1 alone M < 2.0 eV * Fukugita et al. (2006) from WMAP3 alone M < 2.0 eV

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Normalization vs neutrino mass using WMAP alone +

concordance model

Is CMB polarisation useful for neutrino mass?

Fukugita, Ichikawa,

Kawasaki, OL, astro-ph/0605362

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Not directly, but reduces degeneracy with the reionization optical depth

Ratio of bulk flows with massive neutrinos =0.04

Deriving Neutrino mass from Cosmology

Data Authors Mmi

2dF (P01) Elgaroy, OL et al.02 < 1.8 eV

WMAP+LSS+SN…

Spergel et al. 06 < 0.68 eV

2dF (C05)+CMB Sanchez et al. 05 < 1.2 eV

BAO+CMB+LSS+SN

Goobar et al. 06 < 0.62 eV

Ly- + SDSS+ WMAP+…

Seljak et al. 04 < 0.17 eV

WMAP alone Ichikawa et al. 04

Fukugita et al. 06

< 2.0 eV

All upper limits 95% CL, but different assumed priors !

Forecasting Neutrino mass from Cosmology

Data Authors error

High-z galaxy surveys + Planck

Takada et al. (2006) 0.03-0.06 eV

High-z galaxy surveys + Planck

Hannestad & Wong (2007)

0.05 eV

SKA + Planck Abdalla & Rawlings(2007)

0.05 eV

Note different error definitions and assumed priors !

Combined Cosmology & Terrestrial Experiments

Fogli et al.Hep-ph/0408045

Combining KATRIN+CMB (Host, OL, Abdalla & Eitel 2007) =>> Ole’s talk

Neutrinos - Summary * Redshift surveys (+ CMB) M < 0.7-1.8 eV

Ly-(+ CMB+LSS) M < 0.17 eV

* Within the -CDM scenarios, subject to priors. * Alternatives: MDM ruled out. * Future: errors down to 0.05 eV using SDSS+Planck, and weak gravitational lensing of background

galaxies and of the CMB. Resolve the neutrino absolute mass!

Baryon Wiggles as Standard Rulers

Imaging Surveys Survey Sq. Degrees Filters Depth Dates Status

CTIO 75 1 shallow published

VIRMOS 9 1 moderate published

COSMOS 2 (space) 1 moderate complete

DLS (NOAO) 36 4 deep complete

Subaru 30? 1? deep 2005? observing

CFH Legacy 170 5 moderate 2004-2008 observing

RCS2 (CFH) 830 3 shallow 2005-2007 approvedVST/KIDS/

VISTA/VIKING 1700 4+5 moderate 2007-2010? 50%approved

DES (NOAO) 5000 4 moderate 2008-2012? proposedPan-

STARRS ~10,000? 5? moderate 2006-2012? ~funded

LSST 15,000? 5? deep 2014-2024? proposed

JDEM/SNAP1000+ (space)

9 deep 2013-2018? proposed

VST/VISTA

DUNE

5000? 2010-2015?moderate 4+5 proposed

20000? (space) 2+1? moderate 2012-2018? proposed

Y. Y. Mellier

DUNE: Dark UNiverse Explorer

Mission baseline: • 1.2m telescope • FOV 0.5 deg2

• PSF FWHM 0.23’’• Pixels 0.11’’ • GEO (or HEO) orbit

Surveys (3-year initial programme):• WL survey: 20,000 deg2 in 1 red broad band, 35 galaxies/amin2 with median z ~ 1, ground based complement for photo-z’s

• Near-IR survey (J,H). Deeper than possible from ground. Secures z > 1 photo-z’s

• SNe survey: 2x60 deg2, observed for 9 months each every 4 days in 6 bands, 10000 SNe out to z ~ 1.5, ground based spectroscopy

Photometric redshift

• Probe strong spectral features (4000 break)

• Difference in flux through filters as the galaxy is redshifted.

*Training on ~13,000 2SLAQ

*Generating with ANNz Photo-z for ~1,000,000

LRGs MegaZ-LRG

z = 0.046

Collister, Lahav,Blake et al., astro-ph/0607630

Baryon oscillations

Blake, Collister, Bridle & Lahav; astro-ph/0605303

The Dark Energy Survey• Study Dark Energy using 4 complementary techniques: I. Cluster Counts II. Weak Lensing III. Baryon Acoustic Oscillations IV. Supernovae

• Two multi-band surveys 5000 deg2 g, r, i, z 40 deg2 repeat (SNe)

• Build new 3 deg2 camera and data management system Survey 2010-2015 (525 nights) Response to NOAO AO

Blanco 4-meter at CTIO

300,000,000 photometric redshifts

The DES CollaborationFermilab: J. Annis, H. T. Diehl, S. Dodelson, J. Estrada, B. Flaugher, J. Frieman, S. Kent, H. Lin, P. Limon, K. W. Merritt, J. Peoples, V. Scarpine, A. Stebbins, C. Stoughton, D. Tucker, W. WesterUniversity of Illinois at Urbana-Champaign: C. Beldica, R. Brunner, I. Karliner, J. Mohr, R. Plante, P. Ricker, M. Selen, J. ThalerUniversity of Chicago: J. Carlstrom, S. Dodelson, J. Frieman, M. Gladders, W. Hu, S. Kent, R. Kessler, E. Sheldon, R. WechslerLawrence Berkeley National Lab: N. Roe, C. Bebek, M. Levi, S. PerlmutterUniversity of Michigan: R. Bernstein, B. Bigelow, M. Campbell, D. Gerdes, A. Evrard, W. Lorenzon, T. McKay, M. Schubnell, G. Tarle, M. TecchioNOAO/CTIO: T. Abbott, C. Miller, C. Smith, N. Suntzeff, A. WalkerCSIC/Institut d'Estudis Espacials de Catalunya (Barcelona): F. Castander, P. Fosalba, E. Gaztañaga, J. Miralda-EscudeInstitut de Fisica d'Altes Energies (Barcelona): E. Fernández, M. MartínezCIEMAT (Madrid): C. Mana, M. Molla, E. Sanchez, J. Garcia-BellidoUniversity College London: O. Lahav, D. Brooks, P. Doel, M. Barlow, S. Bridle, S. Viti, J. Weller University of Cambridge: G. Efstathiou, R. McMahon, W. Sutherland University of Edinburgh: J. Peacock University of Portsmouth: R. Crittenden, R. Nichol, R. Maartnes, W. PercivalUniversity of Sussex: A. Liddle, K. Romer

plus postdocs and students

The Dark Energy Survey UK Consortium

(I) PPARC funding: O. Lahav (PI), P. Doel, M. Barlow, S. Bridle, S. Viti, J. Weller (UCL), R. Nichol (Portsmouth), G. Efstathiou, R. McMahon, W. Sutherland (Cambridge) J. Peacock (Edinburgh)

Submitted a proposal to PPARC requesting £ 1.7M for the DES optical design. In March 2006, PPARC Council announced that it “will seek participation in DES”. PPARC already approved £220K for current R&D.

(II) SRIF3 funding: R. Nichol, R. Crittenden, R. Maartens, W. Percival (ICG Portsmouth) K. Romer, A. Liddle (Sussex)

Funding the optical glass blanks for the UCL DES optical work

These scientists will work together through the UK DES Consortium. Other DES proposals are under consideration by US and Spanish funding agencies.

DES Forecasts: Power of Multiple Techniques

Assumptions:Clusters: 8=0.75, zmax=1.5,WL mass calibration

BAO: lmax=300WL: lmax=1000(no bispectrum)

Statistical+photo-z systematic errors only

Spatial curvature, galaxy biasmarginalized,Planck CMB prior

Factor 4.6 improvement over Stage II

w(z) =w0+wa(1–a) 68% CL

DETF Figure of Merit: inversearea of ellipse

DES z=0.8 photo-z shell

Back of the envelope: improved by sqrt (volume) => Sub-eV from DES(OL, Abdalla, Black; in prep)

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0.0 eV0.40.91.7

• * 4-5 complementary probes

• * Survey strategy delivers substantial DE science after 2 years

• * Relatively modest (~ $20-30M), low-risk, near-term project with high discovery potential

• * Synergy with SPT and VISTA on the DETF Stage III timescale

• * Scientific and technical precursor to the more ambitious Stage IV Dark Energy projects to follow: LSST and JDEM

DES and a Dark Energy Programme

Some Outstanding Questions:

* Vacuum energy (cosmological constant, w= -1.000 after all ?) * Dynamical scalar field ? * Modified gravity ?

* Why /m = 3 ? * Non-zero Neutrino mass < 1eV ? * The exact value of the spectral index: n < 1 ?

* Excess power on large scales ? * Is the curvature zero exactly ?