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Japanese VLBI Network

Japanese VLBI Network. FUJISAWA Kenta (Yamaguchi University). AP-RASC ‘10 Toyama 10/09/23. Japanese VLBI Network (JVN) since 2004. Collaboration NAOJ (VERA) Hokkaido, Ibaraki, Tsukuba, Gifu, Osaka-Pref, Yamaguchi, Kagoshima university JAXA, NICT, GSI 13 telescopes (11m ~ 64m) Purpose

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Japanese VLBI Network

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  1. Japanese VLBI Network FUJISAWA Kenta (Yamaguchi University) AP-RASC ‘10 Toyama 10/09/23

  2. Japanese VLBI Network (JVN)since 2004 • Collaboration • NAOJ (VERA) • Hokkaido, Ibaraki, Tsukuba, Gifu, Osaka-Pref, Yamaguchi, Kagoshima university • JAXA, NICT, GSI • 13 telescopes (11m ~ 64m) • Purpose • A new, characteristic VLBI array • A Base of East-Asian VLBI • Ground Array for VSOP-2 • Progress • Started in 2004 • Steady Observation in 2005 • First Paper published in 2006 • Observing time ~200 hr/yr • EAVN test observation 2008- JVN 13 Telescopes

  3. Specification • Baseline 50 - 2500 km • Frequency Bands 8/22/6.7 GHz • 8 – continuum, 22 – water maser/cont, 6.7 – methanol • Beam size • 4 mas @ 6.7 GHz • 3 mas @ 8 GHz • 1 mas @ 22 GHz • Sensitivities (8 GHz) • Current 128 Mbps system • Detection 20 mJy without Phase-Referencing 3 mJy with Phase-Referencing • Image 106 K • New Technologies • High-Speed e-VLBI (2 Gbps) operational in subarray

  4. Good Performance as expected Test Observation • Observations • Nov and Dec, 2004 • 8.4 GHz, 8 telescopes • Source 1928+738 • Results • Beam size 2.5 mas • Peak intensity 1.5 Jy/beam • Noise-level 1s = 1.1 mJy • Dynamic range 1400 • Large-scale 20 mas • Low-brightness ~107K • Reproducibility <1mas

  5. Narrow-Line Seyfert 1 Radio GalaxyDoi et al. (2007) PASJ 59, 703 • Observation • 8.4 GHz, Phase-referencing • 5 sources • Results • Tb ~ 107K • → Synchrotron radiation, but inverted spectrum • Doppler boosting is significant for the radio property of NLS1

  6. Micro-quasar Cyg X-3Tsuboi et al. (2008) PASJ, 60, 465 • Observation • 2006 Feb flare • Only 3.5 days after a major flare • Results • Simple circular structure • Low-noise map • DTb = 1.4 x 106 K • No jet is seen • Jet is formed >3.5 days after a flare

  7. Late-type star NML-Cyg Nagayama et al. (2008) Led by Kagoshima University Star forming region WB755 Motogi et al. (2008) Led by Hokkaido University Results of 22GHz Observation

  8. Methanol Maser VLBI SurveySugiyama et al. (2008) • Observation • Yamaguchi, Mizusawa, Ishigaki • 13 sources • Results • 12 sources image • Distribution for ~1000s AU • Fine structure of spots (<3mas) • Good for Astrometry Led by Yamaguchi univ

  9. Radio/gamma-ray burst of 3C84

  10. Ibaraki 32m x 2 telescopes(Hitachi & Takahagi) Takahagi 32m Test observation succeeded Hitachi 32m VLBI succeeded

  11. JVN web site

  12. Recent Publications • The 2006 Radio Outbursts of a Microquasar Cygnus X-3: Observations and Data • Tsuboi et al. (2008) • A Synchronized Variation of the 6.7 GHz Methanol Maser in Cepheus A • Sugiyama et al.(2008) • Mapping Observations of 6.7 GHz Methanol Masers with the Japanese VLBI Network • Sugiyama et al. (2008) • Microstructure and kinematics of H2O masers in the massive star forming region IRAS 06061+2151 • Motogi et al. (2008) • H2O Maser Outflow from the Red Supergiant Star NML Cygni observed with Japanese VLBI Network • Nagayama et al. (2008) • VLBI Detections of Parsec-Scale Non-Thermal Radio-Loud Broad Absorption Line Quasars • Doi et al. (2009) • VLBI Detections of Parsec-Scale Nonthermal Jets in Radio-Loud Broad Absorption Line Quasars • Doi, A. et al., 2009, PASJ, 61, 1389 • VLBI Monitoring of 3C 84 (NGC 1275) in Early Phase of the 2005 Outburst • Nagai, H. et al., 2010, PASJ, 62, L11

  13. Observations in 2009 Session 36 8 GHz 22 22 GHz 4 6.7 GHz 10 250 hours System upgrade Ibaraki 32m 22GHz VLBI at Tsukuba 32m EAVN Test observation Miyazaki-san Calibration upgrade New Wideband system Underway… Operation Status

  14. Future Plan • East-Asian VLBI Network • Collaboration with CVN/KVN (and Australia?) • New VLBI system • 2/4 Gbps e-VLBI system • Wideband disk recording system (Octavia) • Software correlator (Mitaka correlation center) • Left / Right dual polarization receiving system • 22 GHz observation more intensively • VSOP-2 • JVN / EAVN to be one of the Ground VLBI Arrays • Preparation for VSOP-2 started

  15. 2500 km 5000 km

  16. EAVN in newspapers 2009-10-06 Sankei Shimbun 2008-09-01 Asahi Shimbun

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