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Euclid

Euclid. A Space Mission to Map the Dark Universe R. Laureijs (ESA), A. Refregier (CEA), A. Cimatti (Univ. Bologna), on behalf of the (growing) Euclid Community. Opportunity. ESAs Cosmic visions programme has selected a dark energy mission as a possible candidate for a launch slot in 2017.

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Euclid

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  1. Euclid A Space Mission to Map the Dark Universe R. Laureijs (ESA), A. Refregier (CEA), A. Cimatti (Univ. Bologna), on behalf of the (growing) Euclid Community Dark Energy - Leopoldina Munich

  2. Opportunity • ESAs Cosmic visions programme has selected a dark energy mission as a possible candidate for a launch slot in 2017. • Euclid will address the outstanding questions in cosmology • Nature of the Dark Energy • Nature of the Dark Matter • Initial conditions • Theory of Gravity Dark Energy - Leopoldina Munich

  3. Outline • Euclid selection and concept • Science Objectives • Mission • Payload • Status and programmatics Dark Energy - Leopoldina Munich

  4. Selection of ESAs Dark Energy Mission • Dark energy is recognized by the ESA Advisory Structure as the most timely and important science topic among the M mission proposals and is therefore recommended as the top priority. • Dark energy was addressed by two Cosmic Visions M proposals: • DUNE(PI: A. Refregier-CEA Saclay) – All sky visible and NIR imaging to observe weak gravitational lensing • SPACE(PI: A. Cimatti – Bologna Univ.) – All sky NIR imaging and spectroscopy to detect baryonic acoustic oscillations patterns • An Advisory Team recommended a concept for a single M-Class Dark Energy Mission Dark Energy - Leopoldina Munich

  5. Euclid’s Concept • Named in honour of the pioneer of geometry • Euclid will survey the entire extra-galactic sky (20 000 deg2) to simultaneously measure its two principal dark energy probes: • Weak lensing: • Diffraction limited galaxy shape measurements in one broad visible R/I/Z band.AB=24.5 mag • Redshift determination by Photo-z measurements in 3 NIR bands (Y,J,H) to H(AB)=24 mag, 5σ point source • Baryonic Acoustic Oscillations: • Spectroscopic redshift survey for 33% of all galaxies brighter than H(AB)=22 mag, σz<0.001 • With constraints: • Aperture: max 1.2 m diameter • Limited number of NIR detectors • Mission duration: max ~5 years Dark Energy - Leopoldina Munich

  6. space weak lensing shear ground WL: shear measurement Typical cosmic shear is ~ 1%, and must be measured with high accuracy In Space: availability of small and stable PSF: larger number of resolved galaxies  reduced systematics Dark Energy - Leopoldina Munich

  7. WL: Obtaining NIR photometric redshifts OPT+IR OPT zphoto zspec zspec Abdalla et al. • Will need redshifts for 109 galaxies − photo-z error possible to ~5% in combination with ground-based Pan-Starrs survey etc. • But need 1-2 micron IR for z >1 − impossible from ground (sky brightness) • Need >105 spectroscopic redshifts for calibration Dark Energy - Leopoldina Munich

  8. NIR Spectroscopy: DMD based multi-object slit spectroscopy DMD= Digital Micro-mirror Device Dark Energy - Leopoldina Munich

  9. Euclid’s Primary Science Objectives Dark Energy - Leopoldina Munich

  10. Other Probes • Besides its two principal dark energy probes, Euclid will obtain information of: • Galaxy clustering: the full power spectrum P(k) • Determination of the expansion history and the growth factor using all available information in the amplitude and shape of P(k) • Redshift-space distortions: • Measures the growth rate (derivative of growth factor) from the redshift distortions produced by peculiar motions. • Number density of clusters • Measures a combination of of growth factor (from number of clusters) and expansion history (from volume evolution). • Integrated Sachs-Wolfe Effect • Measures the expansion history and the growth. Dark Energy - Leopoldina Munich

  11. Why is the combined mission so powerful High precision and accurate DE measurements require a combination of two or more probes. Euclid aims at the most promising dark energy probes: an all sky survey of weak lensing and galaxy redshifts. • The weak lensing will reconstruct directly the distribution of the dark matter and the evolution of the growth rate of dark matter perturbations with redshift. • The baryon acoustic oscillations act as standard rods,determine P(k) and provide a measure of H(z) and hence w(z). They also map out the evolution of the baryonic component of the Universe. • Together, these enable many systematic effects to be controlled – for example, intrinsic alignments in weak lensing, bias factors in baryon acoustic oscillations. • Both act as independent dark energy probes. If they differ, we learn about modifications to GR. Dark Energy - Leopoldina Munich

  12. Predicted redshift dependence of w(z) errors Planck prior is used. The errors are calculated using Fisher matrices using a w(a)=w0+(1-a)wa model, hence the caveat that the errors shown here are correlated (from J. Weller). Dark Energy - Leopoldina Munich

  13. Euclid’s Legacy • Visible/NIR imaging survey: morphologies and vis/NIR colors for billions of galaxies out to z~2, 3D dark matter map • Spectroscopic survey: 3D map of the luminous matter distribution, spectra of ~200 million galaxies to z~2 • Deep survey: infrared imaging to H(AB)=26 and spectroscopy to H(AB)=24, galaxies with 2<z<7. Objects at z>7 and up to z~10 can be colour-selected from the Y,J,H colours  Impossible to reach from the ground Dark Energy - Leopoldina Munich

  14. Mission profile (1) CDF study case Launcher SOYUZ ST 2-1b from Kourou Launch mass margin: 28% Sky coverage 20 000 sq. degrees extragalactic sky Two galactic polar caps, latitudeb> 30° Solar aspect angle adjusted for scan optimisation Dark Energy - Leopoldina Munich

  15. Mission profile (2) Orbit Large amplitude Lissajous around SEL2 Free insertion, 30-day transfer time DeltaV budget: 50 m/s Orbit maintenance: 1 manoeuvre/month First Assessment: All mission elements are standard and feasible Spacecraft Body-mounted solar array, 3-axis stabilised platform Relative pointing error: 25 marcsec with FGS Attitude control with proportional cold gas system Hydrazine propulsion for orbit manoeuvres Satellite mass (wet): 1540 kg Communications Housekeeping in X-band, Science telemetry in K-band 700 Gbits/day after compression 4 hours/day link with Cebreros 35-m antenna Mission duration: 5 years including commissioning Dark Energy - Leopoldina Munich

  16. Payload (1) Telescope 1.2 meter Korsch TMA Thermal Passive cooling CCDs at T=170 K NIR detectors at T=140 K Power One power conditioning unit per instrument Total payload: ~200 W peak Data-handling Spectroscopy target selection Full frame images lossless compression NIR detectors noise reduction Dark Energy - Leopoldina Munich

  17. NIS NIP VIS Payload (2) 3 instruments Visible Imaging VIS: 0.21” PSF at 800 nm, 0.1”/pixel NIR Photometry NIP: 0.33”/pixel, 3 bands (Y, J, H) NIR Spectroscopy NIS: 0.9-1.7 m, set of 3 cameras, multi-objects (micro-mirror array), R~400 Each of them with a field of view ~0.48 deg2 • Observation mode • Step and stare case fully investigated • Continuous scanning requires a de-scan mechanism for infrared channels Payload mass ~660 kg, including 300 kg for the 3 instruments First Assessment: High technological readiness with some level of complexity Dark Energy - Leopoldina Munich

  18. Status and programmatics • Two independent industrial studies have started on the system (including mission and payload): 1 year study until Sep 2009 • Two payload consortia: • Euclid Imaging Channels (EIC),headed by A. Refregier (CEA, France) • Euclid Near-Infrared Spectrometer (ENIS), headed by A. Cimatti (Univ Bologna, Italy) 10 month study until Aug 2009 • DMD flight qualification study started • Overall coordination by ESA and the Science Study Team • Down selection in 2009 • Definition phase 2010-2012 • Implementation phase 2012-2017 Dark Energy - Leopoldina Munich

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