Cosmology with the ESA Euclid MissionAndrea Cimatti

Università di Bologna – Dipartimento di Astronomia

On behalf of the “Euclid – Italy” Team

• ESA Cosmic Vision 2015-2025M-class Mission Candidate

• Selected in February 2010

• 2010-2011: Definition phase (mid 2011: M1/M2 selection)

• 2017-2018 : launch of M1-M2 missions

XCVI Congresso Nazionale SIF – Bologna 20-24 Settembre 2010

Baryons (4%)

DARK Universe(76% Dark Energy + 20% Dark Matter)

Dark Energy Affects cosmic geometry and structure growth

Parameterised by equation of state: P/ρ = w w < –1/3 : required to have acceleration Latest best estimate (assuming w=const !): w = –1.03 ± 0.09 (Amanullah et al. 2010) w = -1 : cosmological constant (Einstein’s Λ) w > -1 : “quintessence” (scalar field variable in space and time) w < -1 : “exotic” physics (e.g. increase with time)

Or : Modification of General Relativity ? Void model ? Other ?

Requirements for DE “experiments”

w(a)=w0+(1-a)wa

- ≤ 1% precision on w0 (now ≈30%)- ≤ 10% on wa (now ≈100%)

Komatsu et al. 2009

Linder 2010

w = constant = –1.03 ± 0.09 (Amanullah et al. 2010)

Linder 2010

Weak gravitational lensing

Baryonic Acoustic Oscillations

Redshift-space distorsions

Clusters of galaxies

Integrated Sachs-Wolfe effect

Type Ia Supernovae

Multi-probe approach multi-purpose cosmology mission

mass and shear distribution

⇒

Weak Gravitational Lensing

• Map the 3D distribution of Dark Matter in the Universe• Measures the mass without assumptions on the relation between mass and light• Power spectrum very sensitive to Dark Energy through geometry and growth→ Need measurements of galaxy shapes and photometric redshifts

Euclid Slitless Spectroscopy

For each galaxy:RA, Dec, Redshift 3-D map

Boxes atdifferent redshifts: Evolution

70 million star-forming galaxies at 0.5<z<2 in ≈ 19 h-3 Gpc3

Constrain H(z) (radial) Constrain DA(z) (tangential)

H(z) & DA(z) depend on w(z)

CMB (z≈1000)

galaxies (z≈1)

galaxies (z≈0.6)

Baryonic AcousticOscillations (BAO)

Planck

CMB characteristic scale ≈ 150 Mpc

only 20%of the survey !

Preferred “distance”in galaxy 2-point 3-D correlation function

“Wiggles” in the galaxy largescale distribution power spectrum

Measuring BAO

Full Power Spectrum P(k)• Primordial fluctuations and models of inflation• Non-Gaussianity• Sum of neutrino masses with 0.04 eV accuracy• Complementary to CMB

Additional Cosmology Probes (for free) Test of Gravity and GR• Anisotropy of radial vs tangential clustering• Impossible with photometric redshifts !• Test of Modified Gravity theories• Precision of 2% on the growth exponent γ• Break degeneracies for models with same H(z)

SDSS

2dFGRS

SDSSLRGs

2SLAQVVDS

Euclidspetroscopy

Clusters of galaxies Growth of structures and DE

Dark Matter Halos 108-1015 Msun, mass profiles

Integrated Sachs-Wolfe effect

Type Ia SNe (≈ 2000-4000 to z ≈ 1)

Spectroscopic redshifts: σz = 0.001(1+z)

Photometric redshifts: σz = 0.02(1+z)

WHY FROM SPACE ? IR background: 500x less & stable Stable PSF (WL & spec) Homogeneous data 0.5 < z < 2 with Hα Selection function Unbeatable speed Multi-probe experiment NIR imaging to AB=24 unfeasible from ground on 20,000 deg2

Complementary with ground

WHY SPECTROSCOPY ?

The Impact of Euclid on Cosmology

Mission elements• L2 Orbit• 4-5 year mission• Telescope: 1.2 m primary diameter

Instruments– VIS: visible imaging channel: 0.5 deg2, 0.10’’ pixels, 0.18’’ PSF,

broad band R+I+Z (0.55-0.92 μm) to AB=24.5, CCD detectors.– NISP: 0.5 deg2, 0.3’’ pixels, HgCdTe detectors Slitless spectra: 1-2 μm, R=500, F>4x10-16 ergs/cm2/s, 0.5<z(Hα)<2 Imaging in Y, J, H bands to AB=24

Galactic PlaneSurvey (TBD)

Deep~40 deg2

Wide Extragalactic20,000 deg2

VIS NISP

Euclid Surveys

+opticalimaging

NIR imaging

NIR spectro.

Unique legacy survey: 2 billion galaxies imaged in optical/NIR to mag 24, 70 million NIR galaxy spectra, full extragalactic sky coverage, Galactic sources

Unique dataset for various fields in astronomy: galaxy evolution, search for high-z objects, clusters, strong lensing, brown dwarfs, exo-planets, etc

Synergies with other facilities: JWST, Planck, eRosita, GAIA, DES, Pan-STARSS, LSST, etc

All data publicly available through the Euclid Legacy Archive

The immenseEuclid legacy

The Italian Role

Joint “Euclid Consortium” = EIC + ENIS consortia (9 Apr 2010)

Italy and France are the major contributors Potential contribution from NASA (from 0% to 33%) 2 Italian members in the Board (A. Cimatti + R. Scaramella) 1 Italian in the ESA Euclid Science Team (A. Cimatti, NISP Scientist) Euclid-Italy Team: ~120 members (financial support from ASI) :• Universities : BO, MI, NA, PD, RM La Sapienza, RM Tor Vergata, SISSA, SNS, TS• INAF : OABO, OABrera, OACT, OANA, OAPD, OARM, OATO, OATS, IASFBO, IASFMI, IFSI

Activities Science (theory & observations) : cosmology, galaxy formation & evolution … Instrumentation : electronics, optomechanics, thermal, AIV/AIT… Ground Segment : Science Data Centers Italy leads: NISP instrument, Ground Segment, several key science cases (galaxy clustering, galaxy clusters, strong lensing, legacy), plus deputy in other areas

“Euclid – Italy” : open to involve new collaborators

“The” high precision Dark Energy & Cosmology mission Essential and unbeatable synergy of imaging + spectroscopy Euclid will impact the whole astrophysics and cosmology for decades to come

EUCLIDPLANCK