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SKA in context z=8 Fields of View 1deg^2 With Full Sensitivity at subarcsec resolution RMS sensitivity in 8hrs at 1.4 GHz = 23 nJy China KARST Canada LAR US LargeN+Small-D Australia Luneburg Lenses Europe: phased array Australia: Cylindrical Telescopes India: Preloaded parabolas •“White Papers” issued for each concept in 2002 •Reviewed by EMT/ISAC and revised 2003 Concept USA: ‘Nd’ •4640 x 12m parabolic antennas •Full Xcorr inner 2300 ants (35 km), outer ‘stations’ of 13 ants •Advantage: works to high frequency (> 20 GHz) •Disadvantage: no ‘full-sky, full-array’ multibeaming Concept Euro: nD – Phased arrays Advantages: many simultaneous beams, fast response Disadvantage: Max. frequency = 1.4 GHz SKA poster (multi-beams) Disadvantage: max freq = 1.4 GHz SKA and VLBI “SKV” The SKV – Scaled arrays to 5000 km Centimeter observations of thermal sources at mas resolution X PP-disks X NGC1068 Disk SKV + SKV Science • Dust obscured star and black hole formation history a. starburst – AGN connection/discrimination: T_B(5s,8hrs,20mas,1.4GHz)=200K (SSCs, EG HII, SNR,… imaging to z=0.5) b. counting RSNe to z = 3, imaging expansion to z=0.05 c. mapping OH megamasers to z = 0.3 • Imaging water maser disks to z=0.06 • Imaging (faint) GRBs •High redshift radio absorption lines (HI, molecular): probing dense ISM, evolution physical constants •(SM)BH physics: low luminosity AGN -- Jet/accretion disk connection, XDAFs, Extragalactic microQuasars SKV Science •Protoplanetary disks, jets, and planets: imaging thermal emission at subAU scales, astrometry – Jovian planets around non-flaring solar-type stars to 50pc (30,000 stars!), Jupiter bursts to 100 pc. •Solar-Stellar connection: imaging coronal activity to 5pc (30 stars) •Extragalactic pulsars/stellar masers – proper motions •Geodesy – millimeter accuracy => Earth quake prediction? •Scattering and Scintillation – uas astronomy, turbulent ISM/IPM SKV Science •Proper motions of low luminosity AGN to Virgo – ‘mass map’ of the local supercluster •Epoch of Reionization – 21cm absorption by neutral IGM toward 1st radio loud AGN/GRBs/Star forming galaxies For more details see: http://www.euska.org/workshops/hr_ws_MPIfR_Bonn.html Epoch of Reionization End of ‘Dark age’ sets the fundamental benchmark for cosmic structure formation – formation first luminous objects Evolution of the neutral IGM (Gnedin): ‘Cosmic Phase transition’ HI fraction Ionizing intensity density Gas Temp Discovery of the EoR Gunn-Peterson Absorption => f(HI) > 0.01 at z=6.3 (Fan et al. 2002) CMB large scale (>10deg) polarization => f(HI) < 0.5 at z=17 (Kogut et al. 2003) Studying the pristine IGM beyond the EOR: HI 21cm observations with the SKA and LOFAR SKA: A/T = 20000 m^2/K => nJy sensitivity at 1.4 GHz, mJy at 200 MHz Freq range = 0.1 to 20 GHz Resolution = 0.1” at 1.4GHz Imaging the neutral IGM at z=8.5 (Tozzi 2002) Galaxies: 6uJy at 2’ res (= 20 mK) tCDM and OCDM 30 Mpc comoving QSOs: 3uJy/beam at 2’ res With and without soft Xray pre-heating. Difficulty with (LSS) emission observations: Confusion Continuum sources (di Free-Free emission (Oh Matteo et al.2002) & Mack 2002) Cosmic Web after reionization = Ly alpha forest (d <= 10) 1422+23 z=3.62 Womble 1996 N(HI) = 1e13 -- 1e15 cm^-2, f(HI/HII) = 1e-5 -- 1e-6 => Before reionization N(HI) =1e18 – 1e21 cm^-2 Cosmic Web before reionization: HI 21cm Forest Z=9 Z=7 Carilli, Gnedin, Owen 2002 0.008( TCMB 1 z 1/ 2 )( ) f HI (1 d ) TS 10 Absorption – best done at (sub)arcsecond resolution => 1000 km baselines •Mean optical depth (z = 10) = 1% = ‘Radio Gunn-Peterson effect’ •Narrow lines (1 to 10%, few km/s) = HI 21cm forest (d = 10) SKA observations of absorption before the EOR A/T = 2000 m^2/K z = 10 240 hrs 1 kHz/channel z=8 Absorption in primordial disks toward GRBs/Starbursts? N/Dz << minihalos and IGM (<1e-4x) but >> minihalos and IGM (>50x) => Use much fainter radio sources (0.1 mJy): GRB afterglow within disk? or Starburst radio emission? >1 Furlanetto & Loeb 2002 Radio sources beyond the EOR? Luminous radio sources at very high z Radio galaxy: 0924-220 (van Breugel et al) z = 5.19 S_151 = 600 mJy Quasar: 0913+5821 (Momjian et al.) z = 5.12 S_151 = 150 mJy M_BH = 1e9 M_sun 10mas 1” •(sub)arcsec resolution preferred: decrease confusion, allow imaging CO 3-2 at z=6.42 1148+5251 z=6.42 VLA detection of CO 3-2 emission from most distant QSO – within the EoR (Walter, Carilli, Bertoldi) M(dust) = 1e8 M_sun M(H_2) = 2e10 M_sun M_BH = 1 – 5e9 M_sun M_dyn > 1e10 M_sun S_190MHz = 0.1 mJy predicted if dust is heated by star formation 46.6 GHz Radio sources beyond the EOR: sifting problem (1/1400 per 20 sq.deg.) 1.4e5 at z > 6 S_120 > 6mJy 2240 at z > 6 Summary: SKA study of the EoR •‘Complex’ reionization -- GP: F(HI) > 0.01 at z=6.4, CMB pol: F(HI) < 0.5 at z= 20. •Neutral IGM is opaque => need observations longward of 1mm •Neutral, pristine IGM: realm of low frequency radio astronomy. •HI 21cm emission probes large scale structure. •HI 21cm absorption probes intermediate to small scale structure (radio GP effect, ‘21cm forest’, minihalos, proto-disks) – (sub)arcsec resolution decreases confusion, allows imaging. •Constrain: z_reion, detailed structure formation, nature of first luminous sources, ionizing background, IGM heating and cooling. •LOFAR should provide first detections of the neutral IGM at z>6. •SKA will allow for detailed studies. ISSC: SKA planning schedule • 2002 Design concept “white papers” • 2002 Director Appointed: Management plan with ISSC • 2003 Updated design concept “white papers” • 2003 “White papers” on possible locations • 2004 Updated “white papers” on locations • 2005 Choice of SKA location • 2005 Full Proposals for designs to ISSC • 2007 SKA “facility definition” (may merge designs) • 2010-12 SKA construction begins ? • 2015-17 SKA completed ? ISAC Mandates: 1. Revise science case and requirements, involving larger community, and put in context of future capabilities at other wavelengths. Goal: new Taylor-Braun document by Aug. 2004. 2. Evaluate (w. EMT) proposed SKA designs and advise ISSC. final design and site choice by ISSC in 2007 Goal: Current documentation: 1. Science with the Square Kilometer Array, R. Taylor & R. Braun, 1999 (www.skatelescope.org/ska_science.shtml) 2. Perspectives on Radio Astronomy: Science with Large Antenna Arrays, ed. M. van Haarlem, 1999 (ASTRON) 3. SKA memo series: Groningen (2002), Bologna (2002), and Berkeley(2001), science working group reports (www.skatelescope.org/ska_memos.shtml) Discovery of the EOR (Becker et al. 2002) Fast reionization at z = 6.3 => opaque at l_obs < 1 mm Lower limit to z_reio: GP Effect White et al. 2003 f(HI) > 0.01 at z = 6.3 Fan et al. 2002 Upper limit to z_reio: CMB anisotropies Briggs Thompson scattering => polarization •Large scale structure (10’s deg) => relic of EOR • = Ln_es_e = 0.17 => z_reion = 10 to 20 (Kogut et al. 2003) f(HI) < 0.5 at z = 20 f(HI) > 0.01 at zKogut = 6.3 et al. WMAP IGM Thermal History: Spin, CMB, Kinetic and the 21cm signal Tozzi 2002 T_s T_CMB T_K •Initially T_S= T_CMB •T_S = T_CMB => no signal •T_S couples to T_K via Lya scattering •T_S = T_K < T_CMB => Absorption against CMB •T_K = 0.026 (1+z)^2 (wo. heating) •T_CMB = 2.73 (1+z) •T_S > T_CMB => Emission Evolution of <temperatures> in the simulation Confusion by free-free emission during EOR (Oh & Mack 2003) Detection limits Running rms: S_120 > 6 mJy in 240 hrs KS of noise: S_120 > 12mJy Absorption by minihalos (d > 100) (Furlanetto & Loeb 2002) N/Dz(minihalos) = N/Dz(IGM) = 10/unit z at z=8, > 0.02 Inverse Compton losses off the CMB = U_B (radio lobe) CDM structure formation (PS) Efstathiou 1995 M_BH = 0.006 M_spheroid N(1e11, z=6 – 8) = 3/arcmin^2 Evolution of space density of luminous QSOs (Fan et al. 2003) USS samples (de Breuck et al.) z>8 radio galaxies?