1. VERAによる 近傍星形成領域の位置天文観測
Tomoya Hirota (VERA, NAOJ)

2. Nearby SFRs project H2O masers in SFRs within 1 kpc from the Sun
Orion-Monoceros Molecular Cloud complex
Taurus
Perseus
Ophiuchus
Serpens
Cepheus-Cassiopeia
Distribution of molecular
clouds (Dame et al. 1987)

3. Nearby SFRs project Goal of our project To measure distances to
nearby molecular clouds
To reveal structure and
dynamics of molecular
clouds
dynamics of Local arm
Distribution of molecular clouds (Grabelsky et al. 1988)

4. Orion-Monoceros complex
Nearest GMCs/High-mass SFRs
Numbers of H2O masers
Distance estimated
with various
methods
3D-structure of
molecular clouds
Distribution of molecular
clouds (Wilson et al. 2005)
and H2O masers
(Valdettaro et al. 2001)
South Filament (457pc)
Northern Filament (393pc)
Crossbones (465pc)
Orion East (120pc)
Mon R2(800pc)
Scissors (~150pc)
Orion B ( pc)
NGC2149 (425pc)
Orion A ( pc)

5. Orion-Monoceros complex
Orion KL region in Orion A molecular clouds
Optical image CO(J=1-0) NIR(Subaru)

6. Orion KL region
NIR image (Subaru) H2O masers (VERA)

7. Masers in Orion KL region
H2O masers (VERA) SiO masers (VERA; Kim et al.)
Disk?
Jet?

8. Masers in Orion KL region
Kinematics not fully understood
NW-SE outflow(SiO)+ torus(H2O) Disk + NE-SW outflow (SiO)
(Greenhill et al. 1998) (Greenhill et al. 2003)
SiO(VLBA) H2O(VLA)
SiO(VLBA)

9. H2O masers in Orion KL
NIR image (Subaru) H2O masers (VERA)

10. H2O masers in Orion KL Hirota et al. 2007, PASJ, in press
　 = 437+/-19 pc
Error sources
Structure?
Zenith delay?

11. SiO masers in Orion KL Kim et al. in prep. D=401+/-10 pc
Higher precision even with 6-month observations!

12. Proper motion of Orion KL
Proper motion of source I
(3.5 mas, -4.4 mas;
Rodriguez et al. 2005)
Absolute proper motion of
the maser feature
(2.77 mas, mas): 19.7 kms-1
Proper motion of the maser
feature w.r.t. source I
(-0.7 mas, -4.6 mas): 9.7 kms-1
Jet from IRc2/source I?
Further analysis for other spots

13. Perseus complex Nearest cluster forming region
Chain of dark clouds and HII regions, and OB associations
Distance to dark clouds (Cernis 1993)
　　　　　　　　　　　　　　　　　　　　　　　　　 　　Distribution of molecular clouds
= Av map (Ridge et al. 2006)
Per OB2
Taurus B1
IC348
NGC1333
PerOB2
HD278942
NGC1333 B1
L1448 B5
IC348
B1E

14. NGC1333 Nearby low-mass SFR Cluster of YSOs Numbers of HH flows
Cernis (1989):
extinction pc
de Zeeuw et al. (1999):
HIPPARCOS (Per OB)
/-27 pc
Cluster of YSOs
Numbers of HH flows
SII and HI image
(Bally et al. 1996)
HH7-11
10’

15. H2O masers in NGC1333 Hirota et al. 2008, PASJ, in press
4.25+/-0.32 mas =235+/-18 pc

16. Proper motion of NGC1333
We measured absolute proper motion of H2O masers
Intrinsic proper motion of H2O masers?
Galactic rotation: (-0.65, 0.49) mas yr-1 negligible
Remove Solar motion of (U,V,W)=(10.00,5.25,7.17) km s-1
Effect of Solar Motion

17. Proper motion of NGC1333 Proper motion of H2O masers w.r.t. LSR
Disk? Jet?
Prpper motion of VLA4A w.r.t. LSR =0 ?
To be measured with VLA and/or IR?

18. Proper motion of HH7-11 Optical proper motion of HH7-11
Proper motions w.r.t. reference stars in NGC1333
IR absolute proper motion measurements possible?
Proper motion measurements
with HST of HH7-11 (Noriega-
Crespo & Garnavich 2001)

19. Other researches H2O masers in IRAS 16293-2422
Distance measured with 1% accuracy (VLBA: Claussen)
Radio continuum sources in Taurus
147.6+/-0.6, /-0.5, /-0.6 pc
(VLBA, Loinard et al., Torres et al. )
Radio continuum source in Orion Nebula Cluster
/-21 pc (Sandstrom et al. 2007)
Radio continuum sources in Orion Nebula Cluster
414+/-7 pc (Menten et al. 2007)
3 papers on distance measurements of Orion!

20. Nearby SFRs project H2O masers in SFRs within 1 kpc from the Sun
Orion-Monoceros Molecular Cloud complex
Taurus
Perseus
Ophiuchus
Serpens
Cepheus-Cassiopeia
Structure of Local arm?
Distribution of observed maser sources

21. Summary Annual parallax and proper motion of Orion KL
and NGC1333 were successfully measured.
We have not yet analyzed the kinematics (jet/disk?)
of Orion KL and NGC1333.
We aim to reveal structure and dynamics of Local arm.
We need absolute proper motion measurements of powering sources of masers to understand the origin of the masers --- IR astrometry!