1. 国立天文台水沢 VLBI 観測所 廣田朋也 --- あえて水メーザー以外のテーマで ---

2.  YSOs  Pulsars  SNRs, Micro quasars, X-ray binaries, RS-CVn binaries, Massive O stars, WR stars  Various kind of stellar physics  Search for planetary system  Astrometry (e.g. Lestrade et al. 1999)

3.  Non-thermal emission › Gyrosynchrotron due to magnetic activity › Detection toward WTTTs, but non-detection toward protostars --- free-free absorption ? › Non-thermal jet and stellar wind from massive stars  Thermal emission › Extended; detectable with VLA, resolved with VLBI

4.  Magnetic activity  Non-thermal jet, stellar wind › Variable, sometimes flare › Compact (~10R*) › Negative SED › Polarization › Correlation with X-ray Circularly polarized source in NGC1333 (Rordriguez et al. 1999) Thermal Non- thermal

5.  VLBI observations are still limited  Test observations with “OCTAVE”  2048 Mbps connection › 512 MHz bandwidth › Real-time observation

6.  Details › Date: 2008 March, 3 stations › X-band (8 GHz), ~400 MHz effective bandwidth › Phase-referencing with switching › Synthesized beam size ~40mas (for 200 km baseline) › Test for OB/WR stars on 2009 Jun. and Jul.  But failed --- troubles in correlation? › ToO for X-ray flare detected with MAXI on 2010 Sep.  But failed --- non-detection of ref. source and target

7.  Selection of 16 sources › Known non-thermal radio emitting YSOs (VLA) › Known X-ray YSOs (Chandra)  Not unbiased survey Relationship between X-ray and radio luminosity (Gudel 2002)

8.  Example of V773-Tau › FRING (solint=1) solutions with SNR=10-30

9.  Detected sources: fringe-finder › V773 Tau: ~ 7.8 mJy › GMR-12: ~ 9.7 mJy › VSSG14: ~ 4.8 mJy › Large uncertainty due to unknown flux of calibrator  Other sources were not detected › Insufficient calibration? › Insufficient position accuracy? › Thermal sources (UCHII regions, thermal jets)? --- Short-baseline (<50 km) is essential

10.  Upgrade of JVN combined with VERA › VERA will be upgraded to 2 Gbps › VERA+JVN combined array with 1 or 2 Gbps › Higher-sensitivity array for continuum emission --- not only flux, but also brightness sensitivity! › Possibly including KVN, CVN, LBA, EVN!

11.  VERA+JVN combined array with 1 or 2 Gbps Fringe sensitivity with VERA antenna @K-band, 60sec. Integration, 7sigma-level VERAUsudaKashimaTsukuba Yamaguch i IbarakiNobeyama Antenna SEFD (Jy)1800***500600 300 upgrade-VERA; 1000 MHz BW (mJy) 46***2426 19 current OCTAVE; 500 MHz BW (mJy) 64***3437 26 current VERA; 250 MHz BW (mJy)91***4853 37 Fringe sensitivity with VERA antenna @X-band, 60sec. Integration, 7sigma-level VERAUsudaKashimaTsukuba Yamaguch i IbarakiNobeyama Antenna SEFD (Jy)1600170350300250200*** upgrade-VERA; 1000 MHz BW (mJy) 401319181614*** current OCTAVE; 500 MHz BW (mJy) 571927252320*** current VERA; 250 MHz BW (mJy)812638353229*** Image sensitivity, 4hr. Integration, 3sigma-level Number of baseline beam size (mas) 3sigma (mJy) 3sigma (logTb) 3sigma for 5*beamsize (logTb) upgrade-VERA+JVN @K, 1000 MHz BW1510.147.46.1 upgrade-VERA+JVN @X, 1000 MHz BW1540.055.84.4 current OCTAVE @X; 500 MHz BW6100.105.33.9 current VERA @K; 250 MHz BW611.038.36.9 current VERA @X; 250 MHz BW640.917.05.7 この表本当か？

12.  Not always necessary, because › X-band is higher sensitivity for continuum › Non-thermal emission show negative SED  But, … › GMR-A show positive SED › Only a few (or no?) sources observed at multi-frequency with VLBA --- worth trying › In-beam phase-referencing to H 2 O maser!

13. NGC1333 Polarized source Cepheus A

14.  ＶＬＢＡはラージプロジェクト開始 › 惑星探査、近傍星形成領域、パルサーの位置天文観測  LOFAR も全天サーベイ開始？ › 分解能では勝てそう、機動性が必要  e-EVN 、 EVLA も定常化  ALMA 、 SKA と同じ分解能 › これらの研究の準備として今始めなければならない  位置天文観測ならば GAIA 、 JASMINE の先駆け › 準備研究、同じ天体での電波・可視光のフレーム結合 › 可視減光が大きい天体も可能 › イメージングが可能なのが最大の利点

15.  光結合 VLBI から広帯域記録 (disk)VLBI へ  JVN+VERA から KVN, CVN, LBA, EVN との連携まで可能  高感度連続波観測の幕開け  新たなサイエンスのフィールド拡大 AGN>> メーザー ( 星形成・晩期型星 )>> その他 だけからの拡張  コミュニティの拡大と他波長との共同研究 › 電波でも他波長、 VLBI 以外との連携 (ALMA, SKA) › 可視光・赤外・高エネルギーと同じ天体の観測による連携 › MAXI グループとの連携によるトランジェント天体のフォローア ップ  １年後はもうやる価値なし⇒なぜ今やらないのか？