VERA and Japan-Korea collaboration Mareki Honma Mizusawa VLBI observatory, NAOJ

VERA : VLBI Exploration of Radio Astrometry Ishigaki-jimaOgasawara Iriki Mizusawa Target : Galactic masers GHz) Construction completed in 2002 Regular observations from 2004

Current status of astrometry ~25 parallaxes and proper motions (D ~ up to 5 kpc) Sun S269 Schematic view of Galaxy Illustration courtesy: NASA/JPL-Caltech/R. Hurt (SSC/Caltech) NGC 281 ρ oph S Crt Orion NGC 1333 Solar neighborhood VY CMa Parallax + proper motion Proper motion Sgr A OH43 W49N ON2 T Lep SY Scl R UMa L1204 I06058 AFGL2789 I19213 G14 ON1 WB755 WB621 G34 I19181 G48 See PASJ special issue in Feb fore recent results

ON1 ON1 has both H2O and Methanol masers Maser locations H2O maser parallax / kpc (Nagayama+2011) c.f. ) Methanol maser parallax kpc by EVN (Rygl+ 2009)

G D = / kpc (Nagayama +2011) Close to W51M (~5.1 kpc by Sato+2010), though kinematic distances differ (due to V_LSR difference) γ-ray image with Fermi Molecular gas Both W51M and G48 are associated with SNR W51C

MWG Spiral structure 46 SFR masers (20 from VERA + VLBA/EVN) extrapolation of symmetric arms A plan view of MWG ?? GC angle (deg) R (kpc) in log outer arm Perseus arm Sgr arm local arm Perseus is more prominent than Sgr

VERA & VLBA-Bessel Source sharing more sources with shorter time Consistency check sources observed with both arrays

KVN Korean VLBI Network 21m x 3 stations 22, 43, 86, 129 GHz km baselines operating from 2011 KVN Seoul station

Multi-frequency receiving 22/43/86/129 GHz obs. at the same time Phase-transfer from low to high freq.

KVN + VERA array Key features KVN+VERA provides much denser UV coverage 7 stations, 21 Baselines with 300 – 2300 km Common frequency 22 or 43 GHz Joint observing time (~1000 h / yr ?)

VERA+KVN sciences Astrometry Nearby SFR and AGBs that are mainly resolved out only with VERA Faint sources which require higher sensitivity Maser study SiO multi-transition mapping AGN mapping and monitor Sgr A*, gamma-ray blazars, X-ray binaries etc. and more …