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100 SKA stations (2020 )

Projets avec SKA. 100 SKA stations (2020 ). Telescope. Project (~2020) for a giant radiotelescope in the centimetre-metre  range one square kilometre collecting surface 100 x more sensitive than present radio telescopes for spectral line observations

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100 SKA stations (2020 )

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  1. Projets avec SKA 100 SKA stations (2020)

  2. Telescope • Project (~2020) for a giant radiotelescope • in the centimetre-metre  range • one square kilometre collecting surface • 100 x more sensitive than present radio telescopes • for spectral line observations • 1000 x more sensitive than present radio telescopes • for continuum observations • frequencies: 0.15 – 25 GHz ( 1.2cm – 2m) • field of view: 1 ( 100?) square degrees at  21 cm / 1.4 GHz • 8 independent fields of view • angular resolution: 0.01 arcsec at 21 cm / 1.4 GHz •  100 ‘stations’ of 100m diameter, baselines up to ~ 3000 km

  3. Extra-galactic Key Projects KP-4 Galaxy evolution and cosmology (surveys in HI at z up to 2, CO and continuum; nature of dark energy) KP-5 Probing the dark ages (Epoch of Reionisation) (HI in emission/absorption, CO, continuum) reionization Wiggles, for tackling dark energy

  4. Project Time-line • Proposed sites: Argentina, Australia, China, South Africa • Site ranking/description: 09/2006 • Proposed concepts: phased array, large parabolas/cylinders, LNSD • Concept selection: 2009 • Design studies under way: AUS, RSA; CAN, CHN; USA; • Europe (EC FP6 SKA Design Study; 10 MEUR EC) • French participation: • Construction of EMBRACE, a demonstrator of the european • phased array SKA concept (at Westerbork and Nançay in 2007) • R&D towards the choice of this concept for the SKA • Scientific modeling (cosmology – Horizon team) •  Start construction 100,000 m2 SKA pathfinder on the site: 2010 • Construction of full-scale SKA: 2014-2020

  5. Field of view Point source sensitivity of 10 nano-Jy in 8hours At least 1 square degree Goal 50-100 sq deg.

  6. Multi-Beam

  7. EMBRACE Electronic MultiBeam Radio Astronomy ConcEpt THEA array of 1 sq m, built at ASTRON Beamforming system below, to form 2 fields of view Schematic view of EMBRACE demonstrator (fibre network) 100 m2

  8. KP 4 - Galaxy evolution and cosmology 1- HI line surveys All-sky survey would contain a billion galaxies out to z~1.5  Galaxy evolution studies using the most abundant element 2- ‘Dark Energy-measuring-machine’ - acoustic peaks in baryons as function of z - weak gravitational lensing in large fields Measure DE parameters w0 and w1 to 1% accuracy

  9. HI Line surveys HI surveys main reservoir of star formation, galaxy evolution stage  tracer of DM in galaxies  various environments, groups, clusters, interactions All-sky HI surveys presently out to z~0.04, no evolution information SKA: All-sky HI survey is needed out to cosmological distances, to distinguish between various evolution models - All-sky survey would contain a billion galaxies out to z~1.5 - Deeper, targeted surveys ten million galaxies at 2.5<z<3.5 Feasible in 1 year if field-of-view large enough (>10 deg2)

  10. Dark energy measuring machine: I-Wiggles Billion galaxies at z ~1-2 II- Weak Shear 10 billion galaxies, 10 nanoJy

  11. SNAP and SKA compared Resolution and Sky area 2000 SN 0.1<z<1.7

  12. KP 5 - Probing the dark ages 1- Epoch of Reionisation (EoR) occurs at z~6 (?) HI line observations at high z to study ionisation as function of z HI emission tomography HI absorption towards first radio-loud objects 2- First luminous objects: CO line and continuum detections at <20 GHz: CO(1-0) at z>5, detection rate like ALMA for high transitions unobscured views of unprecedented numbers of AGNs etc.

  13. Possible double re-ionization scenario Furlanetto et al 2004

  14. z=11.5 Ionizing - Background Simulation of Reionization log(f_HI) log(gas density) Gnedin (2000) log T z=7 z=4.9

  15. When is the re-ionisation completed? Mass Volume Gnedin 2004 Different ionisation histories With the same zrei OTVET method for RT

  16. Signal from the EoR period, at 21cm 20x20 °, Scale in T(mK) Gnedin & Shaver 2004

  17. Probing the dark age • Use redshifted 21 cm emission to find the tomography • of neutral hydrogen. Problems • The intensity of neutral hydrogen at high redshifts is 100 to 1000 times smaller than foreground sources. • Incomplete modeling available for foreground sources in power spectra and evolution. • need to remove the signals from brighter sources • Radio Galaxies • Radio Relics Synchrotron Emission • Radio Halos Synchrotron Emission • Free-free and line emission from the interstellar medium

  18. Removal of foregrounds Final angular correlation function derived from calculations, observations, and lots of simulations with several assumptions (even on emission of stars!) The 21 cm line is much weaker than several of the other signals…however with processes for data analysis and simulations, it might be possible to meet the challenge…

  19. LOFAR: precursor of SKA New generation of radio-telescopes, with phased arrays l > 1.2m Low-cost antennae:15000 over 100km, then 25000 over 350km Cost from electronics: A few Terabits/s, CPU 10s of Teraflops Operated ny Netherlands: Astro, Geophysics, Agro-technologies « sensors » will use optic fiber arrays, and IBM processors (1) Reionisation epoch (2) Large extra-galactic surveys : galaxy clusters, galaxies starbursts, with wide field (3) Transient phenomena (GRB, SN, LIGO...) instantaneous beam (4) UHE cosmic rays, recently detected with LOPES (LOFAR prototype station) (5) Pulsars

  20. In the middle of band 1 arsec resolution 100 sqdeg field 1mJy sensitivity Demonstration antennae are operationnal Construction begins end of 2005 5 spiral arms with compact core Will serve to learn how to observe with SKA

  21. Timeline

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