SKA Square Kilometre Array Ae1 000 m 2

SKA (Square Kilometre Array) とは • 各周波数バンドで有効開口面積 Ae=1, 000 m 2 • 周波数バンド：　低周波数域をカバー – Low: 50 -300 MHz, Mid: 350 MHz— 10 GHz (High: 10 -25 GHz) • ２段階のタイムライン – Phase 1: Full SKA の 10%スケール、2020年科学的運用開始 SKA 1 -low(豪), SKA 1 -mid(南ア), SKA 1 -survey(豪) – Phase 2: Full SKA、2020年建設開始 • 国際プロジェクト – Board members: 11 countries (and more) – International Science Working Groups KSPs

[MHz]

ASKAP Phased Array Feed (30 deg 2 coverage) SKA 1 -survey [MHz]

Sky noise

Example: intensity maps • Target sciences – HI maps of galaxies at cosmological distances (z>>1) – Eo. R, proto-planetary disks • Imaging dynamics range: 3× 106 (1000 hr integration)

Example: intensity maps Continuum Line 3π str within 2 years 1000 hour integration

Example: SKA 1 -mid Pulsar Survey • 2年間で 36, 000平方度を探査、　１視野600秒積分 • Non-imaging processing • 50μs sampling: ミリ秒パルサー同定、pulse timing, Dispersion Measure 計測 (DM<3000 cm-3 pc)

Example: SKA 1 Pulsar Timing Array • • 毎月48時間観測、10年間継続 ~300 MSPs (? ) 信号雑音比> 1000 Timing の分解能: Δτ=100 ns

Baseline and array sensitivity in SKA 1 • Baseline sensitivity (for calibration) m. Jy-level continuum calibrators useful (~10 m. Jy at present) c. f. SEFD=42 Jy @Parkes 64 -m L-band • Image sensitivity (core-remote baselines only) 10 m. Jy-level OH masers as astrometry targets (~1 Jy)

Number of continuum reference sources • Residual contributed from the atmosphere – Dynamic component (Asaki et al. 2007) Δθ(target – reference) < 24° @1. 5 GHz for 10 μas-level astrometry – Static component (ionosphere) should be taken into account. multiple calibrators • ~30 000 calibrators with Sν>0. 5 m. Jy (estimated from rfc_2013 b) Calibrators for all targets at longest within 1°. 2 SKA 2 detection limit Number of Reference sources per primary 15 -m antenna beam (0. 7°) (SKA Memo 135)

Structure of SKA Japan consortium Adviser N. Sugiyama (Nagoya Uni. ) Chair T. Handa (Kagoshima Uni. ) Industry Forum T. Kumazawa(TOYO) Vice Chair H. Nakanishi (Kagoshima Uni. ) K. Takahashi (Kumamoto Uni. ) Engineering Working Group Chair H. Nakanishi (Kagoshima Uni. ) Science Working Group Chair T. Takeuchi (Nagoya Uni. ) DSP H. Nakanishi(K. U. ) Magnetic field T. Akahori(KASI) Software T. Kurayama(Teikyo) High-z H. Hirashita(ASIAA) Wideband feed H. Ujihara(NICT) Astrometry H. Imai(K. U. ) 126 members NAOJ liaison Y. Hagiwara(NAOJ) Outreach K. Ichiki (Nagoya Uni. ) Funding Procurement H. Imai (Kagoshima Uni. ) AGN H. Ito(Kyoto U) Pulsar O. Kameya(NAOJ) Astrochemistry International SKA Pulsar SWG

SKA-JP engineering activities • Octave band receiving feeds (H. Ujihara, K. Takefuji) • Broad band correlator – Make a spectrometer with ROACH Spectral channel allocation in Δlog(ν) step – Test on a new RX installed NRO 45 m telescope 早稲田大学那須観測所 →青木さん講演

SKAに関する重要文献 SKA-JP wiki: http: //milkyway. sci. kagoshima-u. ac. jp/groups/ska-jp/ SKA Design Reference Mission (version 3 on 2012 May 28) SKA 1 Baseline Design (version 1 on 2013 March 12) SKA memo 130, SKA 1 Preliminary System Description At the entrance gate of the Murchison Radio Astronomy Observatory on 2013 February 15