1.  1987, Whistler: first time I met Malcolm  1989-1991, post-doc at MPIfR: study of molecular gas in UC HII regions (NH 3, C 34 S, CH 3 CN) with 100m and 30m tel.  pc-scale clumps and strong, optically thick emission  1992-…, Arcetri (with Malcolm): NH 3, CH 3 CN observations with VLA & PdBI  0.1 pc HMCs, cradles of OB stars  1994-…, younger phase??? Luminous IRAS sources, with H 2 O maser but w/o UCHII Forward

2. IRAS 20126+4104: the story  1994: 30-m survey of IRAS sources with H 2 O maser: 13 CO, CS, C 34 S, CH 3 OH, HCO +, HCN, CH 3 CN  dense clumps and outflows  1995: PdBI follow up of ‘‘wisely’’ chosen source: IRAS 20126+4104 DC config., 4 antennas, only 3mm RX: HCO + (1-0); CH 3 CN(5-4) v=0,1; CH 3 13 CN(5-4)

6. IRAS 20126+4104: the story  1994: 30-m survey of IRAS sources with H 2 O maser: 13 CO, CS, C 34 S, CH 3 OH, HCO +, HCN, CH 3 CN  dense clumps and outflows  1995: PdBI follow up of ‘‘wisely’’ chosen source: IRAS 20126+4104 DC config., 4 antennas, only 3mm RX HCO + (1-0); CH 3 CN(5-4) v=0,1; CH 3 13 CN(5-4)

7. Results HCO +  bipolar outflow –different orientation wrt Wilking et al. (1990) –blue- & red-shifted in both lobes CH 3 CN  rotating disk (?) –velocity gradient perpendicular to outflow NIR  H 2 jet; embedded cluster Open questions oCO & HCO + : one or two outflows? oCH 3 CN: rotation or expansion?

8. Wilking et al. (1990) blue-shifted red-shifted

9. HCO + (1-0) high-velocity low-velocity

10. Results HCO +  bipolar outflow –different orientation wrt Wilking et al. (1990) –blue- & red-shifted in both lobes CH 3 CN  rotating disk (?) –velocity gradient perpendicular to outflow NIR  H 2 jet; embedded cluster Open questions oCO & HCO + : one or two outflows? oCH 3 CN: rotation or expansion?

11. outflow axis 3 arcsec resolution

12. Results HCO +  bipolar outflow –different orientation wrt Wilking et al. (1990) –blue- & red-shifted in both lobes CH 3 CN  rotating disk (?) –velocity gradient perpendicular to outflow NIR  H 2 jet; embedded cluster Open questions oCO & HCO + : one or two outflows? oCH 3 CN: rotation or expansion?

13. Results HCO +  bipolar outflow –different orientation wrt Wilking et al. (1990) –blue- & red-shifted in both lobes CH 3 CN  rotating disk (?) –velocity gradient perpendicular to outflow NIR  H 2 jet; embedded cluster Open questions o CO & HCO + : one or two outflows? o CH 3 CN: rotation or expansion?

14. (?)

15.  1997: PdBI AB config., 5 antennas, 3mm & 1mm H 13 CO + (1-0); SiO(2-1); CH 3 CN & CH 3 13 CN(12-11) Results SiO  bipolar jet –consistent with H 2 jet and HCO + bipolar outflow at high vel. –expanding at 100 km/s CH 3 CN  rotating accretion(?) disk –Malcolm’s insight: line width suggests Keplerian rotation! –peak velocity suggestive of infall Open questions oSiO & HCO + : why is low velocity emission different? oWhat is the mass of the (proto)star?

16. high-velocity low-velocity

18. high-velocity low-velocity

19. Inclination=9° Opening ang.=21° V exp =100 km/s (R/R max )

21.  1997: PdBI AB config., 5 antennas, 3mm & 1mm H 13 CO + (1-0); SiO(2-1); CH 3 CN & CH 3 13 CN(12-11) Results SiO  bipolar jet –consistent with H 2 jet and HCO + bipolar outflow at high vel. –expanding at 100 km/s CH 3 CN  rotating accretion(?) disk –Malcolm’s insight: line width suggests Keplerian rotation! –peak velocity suggestive of infall Open questions oSiO & HCO + : why is low velocity emission different? oWhat is the mass of the (proto)star?

22. jet disk 0.7 arcsec resolution

23. FWHM  R -0.5   Keplerian rotation Malcolm’s insight:

24. FWHM  R -0.5   Keplerian rotation systemic velocity

25. dM acc /dt = 10 -3 M O /yr

26.  1997: PdBI AB config., 5 antennas, 3mm & 1mm H 13 CO + (1-0); SiO(2-1); CH 3 CN & CH 3 13 CN(12-11) Results SiO  bipolar jet –consistent with H 2 jet and HCO + bipolar outflow at high vel. –expanding at 100 km/s CH 3 CN  rotating accretion(?) disk –Malcolm’s insight: line width suggests Keplerian rotation! –peak velocity suggestive of infall Open questions o SiO & HCO + : why is low velocity emission different? o What is the mass of the (proto)star?

27. Zhang et al. (1998, 1999): NH 3 with VLA  Keplerian disk (20 M O star); low-velocity NH 3 in SiO jet Hofner et al. (1999): 3.6 cm cont. with VLA  thermal jet of 1000 AU Moscadelli et al.(2000): H 2 O maser with VLBA  conical jet over < 300 AU Shepherd et al. (2000): 12 CO(1-0) with OVRO  precession of jet/outflow In the meanwhile…

28.  2002: PdBI BC config., 6 antennas, 3mm & 1mm C 34 S(2-1) & (5-4); CH 3 OH(2-1) v=0,1 & (5-4) v=1 Results CH 3 OH  bipolar jet –similar to HCO + low-velocity bipolar outflow –precession explains difference between HV and LV flow C 34 S  disk –Keplerian rotation about 7 M O star –pseudo-Keplerian rotation on larger scales mimics more massive star –temperature & density gradient in disk

29. IRAS 20126+4104 jet in H 2 line H 2 knots

30. IRAS 20126+4104 Cesaroni et al. (2005) Precession model: opening angle=37° V exp =100 km/s 360°/20000 yr Lebròn et al. (2006)

31. Precession explains difference between high- and low-velocity HCO + (1-0) emission!

32.  2002: PdBI BC config., 6 antennas, 3mm & 1mm C 34 S(2-1) & (5-4); CH 3 OH(2-1) v=0,1 & (5-4) v=1 Results CH 3 OH  bipolar jet –similar to HCO + low-velocity bipolar outflow –precession explains difference between HV and LV flow C 34 S  disk –Keplerian rotation about 7 M O star –pseudo-Keplerian rotation on larger scales mimics more massive star –temperature & density gradient in disk

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

34. More and more studies… Edris et al. (2005): CH 3 OH & OH with Merlin  Keplerian rotation (< 20 M O star) Sridharan et al. (2005): K, L’, M’ with UKIRT  disk and binary system (850 AU separation) Trinidad et al. (2005): H 2 O & 1.3cm with VLA  rotation of H 2 O maser jet? Lebròn et al. (2006): 12 CO(2-1) with 30m  precession of outflow

35. IRAS 20126+4104: the picture Clump: 1 pc, 400 M O, 40 K Outflow/jet: 64000 yr, 100 km/s, 8 10 -4 M O /yr, precession every 20000 yr Keplerian disk: 4 M O, 1500 AU, 150 K, > 10 8 cm -3, T & n H2 gradient, accretion(?) at 10 -3 M O /yr (proto)star: 7+/-2 M O, 10 4 L O Best example of circumstellar accretion disk in high-mass (proto)star  important implications on high-mass star formation

36. IRAS 20126+4104: the never-ending story Is the distance 1.7 kpc??? Is the clump counter-rotating???  parallax of 44 GHz CH 3 OH masers  merging of C 34 S Pico Veleta with PdBI  SiO velocity in precessing jet, H 2 O maser VLBI monitoring, high resolution & sensitivity PdBI imaging of CH 3 CN disk, etc. etc.…

38. IRAS 20126+4104: the never-ending story Is the distance 1.7 kpc??? Is the clump counter-rotating???  parallax of 44 GHz CH 3 OH masers  merging of C 34 S Pico Veleta with PdBI  SiO velocity in precessing jet, H 2 O maser VLBI monitoring, high resolution & sensitivity PdBI imaging of CH 3 CN disk, etc. etc.…

39. Still a lot to understand… Malcolm’s tips urgently needed!

41. far from star: T < 200 K close to star: T > 300 K

42. Zhang et al. (1998) Keplerian rotation about 20 M O star

43. Shepherd et al. (2000) H 2 knots

44. Sridharan et al. (2005) disk Yao et al. (2000)

45. Sridharan et al. (2005)

47. cmH2OH2OHCO + CH 3 OH LV SiO HV H 2 NH 3 LV CO(7-6) jet/outflow structure