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 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 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 = d d > d min (M * ) p.m. 2 < GM * /[d min (M * ) ] * ALMA HPBW > 40 mas * VLBI HPBW = 1 mas IRAS 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) IRAS Edris et al. (2005) Sridharan et al. (2005) disk NIR & OH masers CH 3 OH & OH masers IRAS Cesaroni et al. Hofner et al. Moscadelli et al. Keplerian rotation: M * =7 M O Moscadelli et al. (2005) Model (Moscadelli et al. 2005) H 2 O maser spots moving along surface of conical jet with v R model data R IRAS 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) monitoring with 32-m Medicina antenna deceleration along l.o.s. of some features: dV LSR /dt -2 km/s/yr systemic velocity VLBA VLBI MERLIN colored points: predicted positions from ( 0, 0 ), v 0, and a monitoring with 32-m Medicina antenna On-going VLBA monitoring G 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 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 ) M O Beltran et al. (2004) Beltran et al. (2005) Furuya et al. (2002) SMA A1 A2 Beltran et al. (2006) G 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 Hypercompact HII region Moscadelli et al. (2007) Beltran et al. (2007) 7mm free-free & H 2 O masers 500 AU 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 ! G 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 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 G 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 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) G (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 Dec (J2000) Furuya et al. (2008) CH 3 CN Beuther et al. (2006) G (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 H2OH2O CH 3 OH 7mm 1.3cm CH 3 OH Sanna et al. in prep. G (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 Dec (J2000) Furuya et al. (2008) CH 3 CN G (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 1.3cm H2OH2O CH 3 OH X OH Sanna et al. in prep. CH 3 OH relative p.m. Sanna et al. in prep. 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? Conclusions Difficult to interpret masers without high- angular resolution imaging of thermal tracers H 2 O masers: V along l.o.s.