VERA and JapanKorea collaboration Mareki Honma Mizusawa VLBI

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

VERA : VLBI Exploration of Radio Astrometry Construction completed in 2002 Regular observations from 2004 Mizusawa Iriki Ishigaki-jima Ogasawara Target : Galactic masers (H 2 O@22 GHz, Si. O@43 GHz + 6. 7 GHz)

Current status of astrometry • ~25 parallaxes and proper motions (D ~ up to 5 kpc) Schematic view of Galaxy Solar neighborhood NGC 281 ON 1 G 34 L 1204 SY Scl R UMa G 14 WB 755 NGC 1333 ρ oph Orion S Crt I 06058 T Lep VY CMa W 49 N G 48 OH 43 I 19213 AFGL 2789 I 19181 WB 621 NGC 281 ON 2 Sgr A S 269 Sun Illustration courtesy: NASA/JPL-Caltech/R. Hurt (SSC/Caltech) Parallax + proper motion Proper motion See PASJ special issue in Feb. 2011 fore recent results

ON 1 • ON 1 has both H 2 O and Methanol masers H 2 O maser parallax 2. 47 +/- 0. 07 kpc (Nagayama+2011) Maser locations c. f. ) Methanol maser parallax 2. 57+0. 34 -0. 27 kpc by EVN (Rygl+ 2009)

G 48. 61+0. 02 • D = 5. 26 +/- 0. 42 kpc (Nagayama +2011) • Close to W 51 M (~5. 1 kpc by Sato+2010), though kinematic distances differ (due to V_LSR difference) Molecular gas γ-ray image with Fermi Both W 51 M and G 48 are associated with SNR W 51 C

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

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

KVN • Korean VLBI Network • 21 m x 3 stations • 22, 43, 86, 129 GHz • 300 -500 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 Si. O multi-transition mapping • AGN mapping and monitor Sgr A*, gamma-ray blazars, X-ray binaries etc. and more …