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Ofer Lahav University College London

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Neutrino Masses from LSS

Neutrino Masses from the CMB

(III) The Dark Energy Survey

Ofer Lahav

University College London

- SN Ia
- CMB
- LSS – Baryonic Oscillations
- Cluster counts
- Weak Lensing
- Integrated Sachs Wolfe
Physical effects:

* Geometry

* Growth of Structure

* 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

- *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?

- 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

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

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

Colombi, Dodelson, & Widrow 1995

CDM

CDM+HDM

WDM

Massive neutrinos mimic

a smaller source term

Thenumber of neutrino species Nn affects

the expansion rate of the universe, hence BBN.

BBN constraints Nn between 1.7 and 3 (95% CL)

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

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

(Hannestad 2005)

We shall assume Nn =3

Electron, muon and tau neutrinos

Eigen states m1, m2, m3

112 neutrinos per cm3

Wnh2 = Mn/(94 eV)

Based on

measured

squared mass

differences

from solar and

atmospheric

oscillations

Assuming

m1 <m2 <m3

E & L, NJP 05

What could cosmic probes tell us about Neutrinos and Dark Energy?

The Growth factor: degeneracy of Neutrinos Mass and Dark Energy

Kiakotou, Elgaroy, OL

DP(k)/P(k) = -8 Wn /Wm

Not valid on useful scales!

Kiakotou, Elgaroy, OL 2007, astro-ph 0709.0253

- Free streaming effect:
- Wn/Wm< 0.13
Total n mass M< 1.8 eV

- 0.001 < Wn < 0.04
(Oscillations) (2dF)

- a Four-Component Universe ?

Wn= 0.05

0.01

0.00

Elgaroy , Lahav & 2dFGRS team,

astro-ph/0204152 , PRL

- Cosmological (parameters and priors)
- Astrophysical (e.g. Galaxy biasing)
- Instrumental (e.g. ‘seeing’)

n= 0.9

n=1.0

Prior 0< Wm<0.5

n= 1.1

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

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

a

---- SAM for

L>0.75 L*

Total neutrino mass

Elgaroy & Lahav , JCAP, astro-ph/030389

M

Abazajian & Dodelson (2003)

also Hannestad et al. 2006

Abazajian 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

M =0.3, 0.9, 1.5, 6.0 eV

Fixed cdm = 0.26

E&L 2004

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

Fukugita, Ichikawa,

Kawasaki, OL, astro-ph/0605362

Not directly,

but reduces degeneracy with

the reionization optical depth

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

Note different error definitions and assumed priors !

Fogli et al.

Hep-ph/0408045

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

* Redshift surveys (+ CMB) Mn < 0.7-1.8 eV

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

* Within the L-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!

Survey

Filters

Depth

Dates

Status

Sq. Degrees

CTIO

75

1

shallow

published

VIRMOS

9

1

moderate

published

COSMOS

2 (space)

1

moderate

complete

36

4

deep

complete

DLS (NOAO)

Subaru

30?

1?

deep

observing

2005?

170

5

moderate

observing

CFH Legacy

2004-2008

830

3

shallow

approved

RCS2 (CFH)

2005-2007

VST/KIDS/

VISTA/VIKING

1700

4+5

moderate

2007-2010?

50%approved

5000

4

moderate

proposed

DES (NOAO)

2008-2012?

Pan-STARRS

~10,000?

5?

moderate

~funded

2006-2012?

LSST

15,000?

5?

deep

proposed

2014-2024?

1000+ (space)

9

deep

proposed

JDEM/SNAP

2013-2018?

proposed

moderate

5000?

4+5

2010-2015?

VST/VISTA

proposed

moderate

2+1?

DUNE

20000? (space)

2012-2018?

Y.

Y. Mellier

- 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

- Probe strong spectral features (4000 break)
- Difference in flux through filters as the galaxy is redshifted.

z = 0.046

Collister, Lahav,

Blake et al.,

astro-ph/0607630

Baryon oscillations

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

Blanco 4-meter at CTIO

- Study Dark Energy using
4 complementary techniques:

I. Cluster Counts

II. Weak Lensing

III. Baryon Acoustic Oscillations

IV. Supernovae

• Two multi-band surveys

5000 deg2g, 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

300,000,000 photometric redshifts

Fermilab: 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. Wester

University of Illinois at Urbana-Champaign: C. Beldica, R. Brunner, I. Karliner, J. Mohr, R. Plante, P. Ricker, M. Selen, J. Thaler

University of Chicago:J. Carlstrom, S. Dodelson, J. Frieman, M. Gladders,

W. Hu, S. Kent, R. Kessler, E. Sheldon, R. Wechsler

Lawrence Berkeley National Lab: N. Roe, C. Bebek, M. Levi, S. Perlmutter

University of Michigan: R. Bernstein, B. Bigelow, M. Campbell, D. Gerdes, A. Evrard, W. Lorenzon, T. McKay, M. Schubnell, G. Tarle, M. Tecchio

NOAO/CTIO: T. Abbott, C. Miller, C. Smith, N. Suntzeff, A. Walker

CSIC/Institut d'Estudis Espacials de Catalunya (Barcelona):F. Castander, P. Fosalba, E. Gaztañaga, J. Miralda-Escude

Institut de Fisica d'Altes Energies (Barcelona):E. Fernández, M. Martínez

CIEMAT (Madrid): C. Mana, M. Molla, E. Sanchez, J. Garcia-Bellido

University 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. Percival

University 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

w(z) =w0+wa(1–a) 68% CL

Assumptions:

Clusters:

8=0.75, zmax=1.5,

WL mass calibration

BAO:lmax=300

WL:lmax=1000

(no bispectrum)

Statistical+photo-z

systematic errors only

Spatial curvature, galaxy bias

marginalized,

Planck CMB prior

Factor 4.6 improvement over Stage II

DETF Figure of

Merit: inverse

area of ellipse

Mn

0.0 eV

0.4

0.9

1.7

Back of the envelope: improved by sqrt (volume) => Sub-eV from DES

(OL, Abdalla, Black; in prep)

DES and a Dark Energy Programme

- * 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

* 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 ?