1. Associating Sites of Methanol Masers at 6.7 GHz in Onsala 1 2009 East Asia VLBI Workshop, Seoul, Korea 2009, 3, 18-20 Sugiyama, Koichiro 杉山 孝一郎 스기야마 코이치로 (Yamaguchi University)

2. Contents 1. 6.7 GHz methanol maser Associating sites : disk or outflow ? 2. Target : Onsala 1 3. Results 1.Superpose on other masers, lines, continuum 2.Internal proper motions 4. Summary

3. 6.7 GHz methanol maser For study of massive star-forming regions (MSFRs) – –associated with only MSFRs – –tracing early evolutionary phase ： ～ 10 4 yr – –very strong and bright （ second to the water masers ） – –compact ： several AU For astrometry –many sources ： ～ 900 –long lifetime and stable ： > 4 yr –small effect by water vapor Potentially issue –Associating sites ： Disk or Outflow ?

4. Associating sites : disk or outflow ? Disk –Linear structure and velocity gradient => Edge-on rotating disk –Ring structure (Bartkiewicz et al. 2005) –Infall ? (Goddi et al. 2007) Outflow –Expanding shock (< 10 km s -1 ) (Walsh et al. 1998) –Expanding shock (< 10 km s -1 ) (Walsh et al. 1998) –Parallel to H 2 emission (De Buizer 2003) Planar shock (Dodson et al. 2004) G 327.120+0.511 (Phillips et al. 1998) G 320.23-0.28 (De Buizer 2003)

5. 1. indirectly : superpose on other probes –water, OH masers –continuum : UC H II regions, dust emissions –molecular lines : outflow, rotating disk 2. directly : internal proper motions –measure at three epochs Purpose and approach Clarify associating sites of methanol maser

6. Target : Onsala 1

7. Target : Onsala 1 (ON 1) distance : 1.75 kpc (Rygl et al. in 9th EVN symp.) multiple location of MSFRs outflows in various directions water masers, CO, H 2 H 13 CO +, SiO Clear absolute position of methanol maser –measured with the MERLIN (Green et al. 2007) –mapping toward only red- shifted spectral feature Nagayama et al. (2008a) Kumar et al. (2004) CH 3 OH maser

8. Observational table with the JVN at 6.7 GHz velocity resolution : 0.176 km s -1 synthesized beam : ~ 5×3 mas 2 phase referencing ON 1 date 2006, 09, 10 2008, 05, 10 2008, 10, 26 stationsY,U,M,IY,M,I,R,O Y, U, M, I, R, O integration time 3.4 hrs 1.5 hrs 0.5 hrs image sensitivity ＊ 80200320 ＊ unit : mJy beam -1 Y:Yamaguchi 32-m, U:Usuda 64-m, M:Mizusawa 20-m, I:Ishigaki 20-m, R:Iriki 20-m, O:Ogasawara 20-m

9. Results

10. ON 1 --- I : Spatial distribution Separated (spectrum) : ～ 15 km s -1 Boundary of systemic velocity –CS (J=2 ‐ 1) : 11.6±3.0 km s -1 –H76α : 5.1±2.5 km s -1 Isolated (spatial) : ～ 1800 AU –northeast-southwest direction V sys ~12 km s -1 H76 ~5.1 km s -1

11. ON 1 --- II : Superposition Associated with the UC H II region –Coincided with OH maser –Separated from water maser different exciting sources Coincided with the H 13 CO +, SiO outflows –Northeast-southwest PA ~ 44 deg –Low speed : 4.5 km s -1 –~30 times smaller spatial size Similar trend for radial velocity –northeast : blue-shifted southwest : red-shifted Nagayama et al. (2008a) modified by our works

12. Identified 13 spots –within 4 mas (motion) –within 0.18 km s -1 (radial) Direction –roughly Northeast-southwest coincided with H 13 CO +, SiO Velocity of motions –0.4 ~ 7.0 km s -1 Mean value : 3.2 km s -1 Similar to H 13 CO + : 4.5 km s -1 ON 1 --- III : Internal proper motion tracing Outflow ?

13. ON1 --- IV : Comparison with OH masers OH maser –Expanding motions （ Fish & Reid 2007 ） –Tracing expanding UC H II region Methanol maser –Similar to OH maser direction of motions spatial coincidence radial velocities Fish & Reid (2007) の図を改変 tracing the expanding UC H II region ?

14. Expanding shell model Expanding shell model (Nagayama et al. 2008b) –V : H76α~5.1 km s -1 –V sys : H76α~5.1 km s -1 –apply to the OH masers (Fish & Reid 2007) v exp ~5.4 km/s r ~1330 mas r shell ~1330 mas –Unsuitable for methanol masers particularly blue-shifted spots referred from Nagayama et al. (2008b) different from expanding motions of the OH masers

15. Summary 6.7 GHz methanol maser in ON 1 –Isolated in spatial distribution and spectrum –Superposition coincide with the UC HII region, H 13 CO +, SiO outflows coincide with the UC HII region, H 13 CO +, SiO outflows –Internal proper motion directed away between red- and blue-shifted spots roughly northeast-southwest direction –Comparison with the OH masers similar : spatial, radial velocity, proper motion Unsuitable the expanding shell model of OH masers possibly tracing Outflow

16. Prospects Measuring internal proper motions toward many methanol sources with EAVN –play a significant role in a development of EAVN Array construct –Shanghai (will be installed) make UV-coverage in east-west direction –Urumqi form maximum baseline ~3 times longer than that now –Australian stations advantage for observations of equatorial sources