1. 1)OB star formation: pros and contras of maser studies 2)Are maser (VLBI) studies “obsolete”? 3)Association of masers with jets/disks: some examples 4)Conclusion: H 2 O and CH 3 OH masers plus continuum and thermal line needed The synergy between maser and thermal emission In collaboration with: Moscadelli, Beltran, Furuya, Goddi, Sanna, Codella, Zhang, … and many others

2. Pros and Contras of maser observations Advantages: –very bright and pointlike  mas angular resolution –pointlike  excellent “test particles”  3D velocity Inconvenients: –“Christmas tree” effect?  real or apparent velocity? –“patchy” emission  only few lines of sight sampled –variable (>days)  doubtful identification of spots –non-LTE  no physical parameter (n, T, etc.)  Masers are useful, but need complementary info

3. Are maser studies “obsolete”? No! Still unique to measure proper motions, e.g.: outflow/jet: v out = 100 km/s  p.m. 5 kpc Keplerian disk (face on): 3D velocity  M * v 2 = GM * /R v = p.m. d R = θ d d > d min (M * )  p.m. 2 < GM * /[d min (M * ) θ]

4. * ALMA HPBW > 40 mas

5. * VLBI HPBW = 1 mas

6. IRAS 20126+4104 Keplerian disk (CH 3 CN, C 34 S) around 7 M O star + bipolar jet (SiO, free-free, H 2 ) CH 3 OH (class I and II), OH, and H 2 O masers OH and CH 3 OH class II in disk (Edris et al. 2005) CH 3 OH class I (Araya et al. 2008) and H 2 O in jet (Moscadelli et al. 2000) H 2 O masers in decelerating shocks (Moscadelli et al. 2005)

7. IRAS 20126+4104 Edris et al. (2005) Sridharan et al. (2005) disk NIR & OH masers CH 3 OH & OH masers

8. IRAS 20126+4104 Cesaroni et al. Hofner et al. Moscadelli et al. Keplerian rotation: M * =7 M O Moscadelli et al. (2005)

9. Model (Moscadelli et al. 2005) H 2 O maser spots moving along surface of conical jet with v  R model data R

10. IRAS 20126+4104 Keplerian disk (CH 3 CN, C 34 S) around 7 M O star + bipolar jet (SiO, free-free) CH 3 OH (class I and II), OH, and H 2 O masers OH and CH 3 OH class II in disk (Edris et al. 2005) CH 3 OH class I (Araya et al. 2008) and H 2 O in jet (Moscadelli et al. 2000) H 2 O masers in decelerating shocks (Moscadelli et al. 2005)

11. monitoring with 32-m Medicina antenna deceleration along l.o.s. of some features: dV LSR /dt ≈ -2 km/s/yr systemic velocity

12. VLBA VLBI MERLIN colored points: predicted positions from (α 0,δ 0 ), v 0, and a

13. monitoring with 32-m Medicina antenna

14. On-going VLBA monitoring

15. G24.78+0.08 Complex region: 2 UCHIIs, 2 bipolar outflows ( 12 CO, SiO), 3 rotating toroids (CH 3 CN) Infall detected (NH 3 ) in one toroid CH 3 OH (class I and II), OH, and H 2 O masers H 2 O masers around expanding HC HII (Moscadelli et al. 2007, Beltran et al. 2007) around 20 M O star CH 3 OH masers in rotating toroid?? (Moscadelli et al. 2007): M dyn = 18 M O ~ M star ! CH 3 OH spots located “ahead” of HC HII: might trace infall! Expectation: p.m. 10 times smaller than H 2 O

16. Beltran et al. (2004) Beltran et al. (2005) Furuya et al. (2002) SMA A1 A2 Codella et al in prep. hypercompact HII + dust O9.5 (20 M O ) + 130 M O

17. Beltran et al. (2004) Beltran et al. (2005) Furuya et al. (2002) SMA A1 A2 Beltran et al. (2006)

18. G24.78+0.08 Complex region: 2 UCHIIs, 2 bipolar outflows ( 12 CO, SiO), 3 rotating toroids (CH 3 CN) Infall detected (NH 3 ) in one toroid CH 3 OH (class I and II), OH, and H 2 O masers H 2 O masers around expanding HC HII (Moscadelli et al. 2007, Beltran et al. 2007) with 20 M O star CH 3 OH masers in rotating toroid?? (Moscadelli et al. 2007): M dyn = 18 M O ~ M star ! CH 3 OH spots located “ahead” of HC HII: might trace infall! Expectation: p.m. 10 times smaller than H 2 O

19. Hypercompact HII region Moscadelli et al. (2007) Beltran et al. (2007) 7mm free-free & H 2 O masers 500 AU

20. 7mm free-free & H 2 O masers 30 km/s R HII = 600 AU R G = GM * /C II 2 = 100 AU R HII > R G HII not confined (Keto 2002) R HII /V H2O = 40 yr !

21. G24.78+0.08 Complex region: 2 UCHIIs, 2 bipolar outflows ( 12 CO, SiO), 3 rotating toroids (CH 3 CN) Infall detected (NH 3 ) in one toroid CH 3 OH (class I and II), OH, and H 2 O masers H 2 O masers around expanding HC HII (Moscadelli et al. 2007, Beltran et al. 2007) with 20 M O star CH 3 OH masers in rotating toroid?? (Moscadelli et al. 2007): M dyn = 18 M O ~ M star ! CH 3 OH spots located “ahead” of HC HII: might trace infall! Expectation: p.m. 10 times smaller than H 2 O

22. Hypercompact HII region Moscadelli et al. (2007) Beltran et al. (2007) 7mm free-free, H 2 O masers, and CH 3 OH masers M dyn = 18 M O ~ M star

23. G24.78+0.08 Complex region: 2 UCHIIs, 2 bipolar outflows ( 12 CO, SiO), 3 rotating toroids (CH 3 CN) Infall detected (NH 3 ) in one toroid CH 3 OH (class I and II), OH, and H 2 O masers H 2 O masers around expanding HC HII (Moscadelli et al. 2007, Beltran et al. 2007) with 20 M O star CH 3 OH masers in rotating toroid?? (Moscadelli et al. 2007): M dyn = 18 M O ~ M star ! CH 3 OH spots located “ahead” of HC HII: might trace infall! Expectation: p.m. 10 times smaller than H 2 O

24. 7mm free-free, H 2 O masers, and CH 3 OH masers If H 2 O is in post-shock and CH 3 OH is in pre-shock H 2 O spots trace expansion and CH 3 OH spots trace infall (beside rotation)

25. G16.59-0.06 (Sanna et al. in prep) At least 2 bipolar outflows (Beuther et al 2006; Furuya et al. 2008; Sepulcre et al. in prep.) Free-free source (Zapata et al. 2006)  M star = 16 M O from Lyman continuum No velocity gradient: face-on disk? H 2 O masers move along outflows CH 3 OH masers in rotating disk? (face on): M dyn = 25 M O > M star

26. Dec (J2000) Furuya et al. (2008) CH 3 CN

27. Beuther et al. (2006)

28. G16.59-0.06 (Sanna et al. in prep) At least 2 bipolar outflows (Beuther et al 2006; Furuya et al. 2008; Sepulcre et al. in prep.) Free-free source (Zapata et al. 2006)  M star = 16 M O from Lyman continuum No velocity gradient: face-on disk? H 2 O masers move along outflows CH 3 OH masers in rotating disk? (face on): M dyn = 25 M O > M star

29. H2OH2O CH 3 OH 7mm 1.3cm CH 3 OH Sanna et al. in prep.

30. G23.01-0.41 (Sanna et al. in prep.) Bipolar outflow: centred on free-free source Hint of rotation: inclined disk? Free-free source  M star = 16 M O from Lyman continuum All masers types cluster around free-free continuum. CH 3 OH masers in rotating disk: M dyn = 30 M O > M star

31. Dec (J2000) Furuya et al. (2008) CH 3 CN

32. G23.01-0.41 (Sanna et al. in prep.) Bipolar outflow: centred on free-free source Hint of rotation: inclined disk? Free-free source  M star = 16 M O from Lyman continuum All masers types cluster around free-free continuum CH 3 OH masers in rotating disk: M dyn = 30 M O > M star

33. 1.3cm H2OH2O CH 3 OH X OH Sanna et al. in prep.

34. CH 3 OH relative p.m. Sanna et al. in prep.

35. Problems with G16 & G23: M dyn ~ 2 M star –M dyn = M star +M gas ? –Jet instead of HII region? –Luminosity estimate needed! Disk vel. grad. || Outflow axis –Infall inside disk? –Multiple outflows?

36. Conclusions Difficult to interpret masers without high- angular resolution imaging of thermal tracers H 2 O masers: V along l.o.s. << V in plane of sky  in “edge-on” shocks  associated with expanding jets/outflows CH 3 OH masers: V along l.o.s. ~ V in plane of sky  associated with rotating toroids/disks

38. monitoring with 32-m Medicina antenna

39. VLBA MERLIN

40. Masers and OB star formation OH: tight association with UC HIIs (e.g. W3OH, G34.62) H 2 O: good correlation L H 2 O vs L IRAS CH 3 OH class II: yet undetected in low-mass SFRs (see Minier et al.) SiO: detected only in Orion hot core  Most masers in SFRs associated with high-mass stars

41. Codella et al. in prep. A1 A2 B UC HII region B HC HII region A1 thermal jet A2 ? Rotating toroids A1, A2, C Outflows from C and A1/A2 SMA

42. G31.41+0.31 See Maite’s talk! Bipolar outflow (Araya et al. 2008) or rotating toroid (Beltran et al. 2005)?  CH 3 OH (class II), OH, and H 2 O masers proper motions can discriminate between expansion and rotation

43. outflow… toroid…

44. 1200 AU Hofner et al. (in prep.)

45. Beltran et al. (2005); Hofner et al. (in prep.) NH 3 red-shiftedNH 3 blue-shiftedNH 3 bulk CH 3 CN(12-11)

46. Beltran et al. (2004) Beltran et al. (2005) Furuya et al. (2002) SMA A1 A2 hypercompact HII + dust O9.5 (20 M O ) + 130 M O Beltran et al. (2006)