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SKA in context

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 Large-N+Small-D Australia Luneburg Lenses Europe: phased array. Australia: Cylindrical Telescopes. India: Preloaded

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SKA in context

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  1. SKA in context z=8

  2. Fields of View 1deg^2 With Full Sensitivity at subarcsec resolution

  3. RMS sensitivity in 8hrs at 1.4 GHz = 23 nJy

  4. China KARST Canada LAR US Large-N+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

  5. 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

  6. Concept Euro: nD – Phased arrays

  7. SKA poster (multi-beams) Advantages: many simultaneous beams, fast response Disadvantage: Max. frequency = 1.4 GHz Disadvantage: max freq = 1.4 GHz

  8. SKA and VLBI “SKV”

  9. The SKV – Scaled arrays to 5000 km

  10. Centimeter observations of thermal sources at mas resolution X PP-disks X NGC1068 Disk SKV +

  11. 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

  12. 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

  13. 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

  14. Epoch of Reionization End of ‘Dark age’ sets the fundamental benchmark for cosmic structure formation – formation first luminous objects

  15. Evolution of the neutral IGM (Gnedin): ‘Cosmic Phase transition’ HI fraction Ionizing intensity density Gas Temp

  16. 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)

  17. 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

  18. 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.

  19. Difficulty with (LSS) emission observations: Confusion Continuum sources (di Matteo et al.2002) Free-Free emission (Oh & Mack 2002)

  20. Cosmic Webafter 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

  21. Cosmic Web before reionization: HI 21cm Forest Z=9 Z=7 Carilli, Gnedin, Owen 2002 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)

  22. SKA observations of absorption before the EOR A/T =2000 m^2/K 240 hrs 1 kHz/channel z = 10 z = 8

  23. Absorption in primordial disks toward GRBs/Starbursts? N/Dz << minihalos and IGM (<1e-4x) but t>> minihalos and IGM (>50x) => Use much fainter radio sources (0.1 mJy): GRB afterglow within disk? or Starburst radio emission? Furlanetto & Loeb 2002 t > 1

  24. Radio sources beyond the EOR?

  25. 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

  26. CO 3-2 at z=6.42 1148+5251 z=6.42 46.6 GHz 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

  27. 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

  28. 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.

  29. 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 ?

  30. ISAC Mandates: • 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. • Evaluate (w. EMT) proposed SKA designs and advise ISSC. Goal: final design and site choice by ISSC in 2007 • Current documentation: • Science with the Square Kilometer Array, R. Taylor & R. Braun, 1999 (www.skatelescope.org/ska_science.shtml) • Perspectives on Radio Astronomy: Science with Large Antenna Arrays, ed. M. van Haarlem, 1999 (ASTRON) • SKA memo series: Groningen (2002), Bologna (2002), and Berkeley(2001), science working group reports (www.skatelescope.org/ska_memos.shtml)

  31. Discovery of the EOR(Becker et al. 2002) Fast reionization at z= 6.3 => opaque at l_obs < 1 mm

  32. Lower limit to z_reio: GP Effect Fan et al. 2002 White et al. 2003 f(HI) > 0.01 at z = 6.3

  33. Upper limit to z_reio: CMB anisotropies Briggs

  34. Thompson scattering => polarization • Large scale structure (10’s deg) => relic of EOR • t = Ln_es_e = 0.17 => z_reion = 10 to 20(Kogut et al. 2003) f(HI) < 0.5 at z = 20 Kogut et al. WMAP f(HI) > 0.01 at z = 6.3

  35. 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 couples to T_K via Lya scattering • T_K = 0.026 (1+z)^2 (wo. heating) • T_CMB = 2.73 (1+z) • T_S = T_CMB => no signal • T_S = T_K < T_CMB => Absorption against CMB • T_S > T_CMB => Emission

  36. Evolution of <temperatures> in the simulation

  37. Confusion by free-free emission during EOR (Oh & Mack 2003)

  38. Detection limits Running rms: S_120 > 6 mJy in 240 hrs KS of noise: S_120 > 12mJy

  39. Absorption by minihalos (d > 100)(Furlanetto & Loeb 2002) N/Dz(minihalos) = N/Dz(IGM) = 10/unit z at z=8, t > 0.02

  40. Inverse Compton losses off the CMB = U_B (radio lobe)

  41. CDM structure formation (PS) Efstathiou 1995 M_BH = 0.006 M_spheroid N(1e11, z=6 – 8) = 3/arcmin^2

  42. Evolution of space density of luminous QSOs (Fan et al. 2003)

  43. USS samples (de Breuck et al.) z>8 radio galaxies?

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