MALCOLM

Document Sample
MALCOLM Powered By Docstoc
					               Forward
 1987, Whistler: first time I met Malcolm
 1989-1991, post-doc at MPIfR: study of
  molecular gas in UC HII regions (NH3, C34S,
  CH3CN) with 100m and 30m tel.  pc-scale
  clumps and strong, optically thick emission
 1992-…, Arcetri (with Malcolm): NH3, CH3CN
  observations with VLA & PdBI  0.1 pc
  HMCs, cradles of OB stars
 1994-…, younger phase??? Luminous IRAS
  sources, with H2O maser but w/o UCHII
       IRAS 20126+4104: the story

1994: 30-m survey of IRAS sources with H2O
 maser: 13CO, CS, C34S, CH3OH, HCO+, HCN,
 CH3CN  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); CH3CN(5-4) v=0,1; CH313CN(5-4)
       IRAS 20126+4104: the story

1994: 30-m survey of IRAS sources with H2O
 maser: 13CO, CS, C34S, CH3OH, HCO+, HCN,
 CH3CN  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); CH3CN(5-4) v=0,1; CH313CN(5-4)
Results
• HCO+  bipolar outflow
  – different orientation wrt Wilking et al. (1990)
  – blue- & red-shifted in both lobes
• CH3CN  rotating disk (?)
  – velocity gradient perpendicular to outflow
• NIR  H2 jet; embedded cluster
Open questions
o CO & HCO+: one or two outflows?
o CH3CN: rotation or expansion?
               Wilking et al. (1990)


blue-shifted




 red-shifted
HCO+(1-0)


high-velocity




low-velocity
Results
• HCO+  bipolar outflow
  – different orientation wrt Wilking et al. (1990)
  – blue- & red-shifted in both lobes
• CH3CN  rotating disk (?)
  – velocity gradient perpendicular to outflow
• NIR  H2 jet; embedded cluster
Open questions
o CO & HCO+: one or two outflows?
o CH3CN: rotation or expansion?
 3 arcsec
resolution
Results
• HCO+  bipolar outflow
  – different orientation wrt Wilking et al. (1990)
  – blue- & red-shifted in both lobes
• CH3CN  rotating disk (?)
  – velocity gradient perpendicular to outflow
• NIR  H2 jet; embedded cluster
Open questions
o CO & HCO+: one or two outflows?
o CH3CN: rotation or expansion?
Results
• HCO+  bipolar outflow
    – different orientation wrt Wilking et al. (1990)
    – blue- & red-shifted in both lobes
• CH3CN  rotating disk (?)
    – velocity gradient perpendicular to outflow
• NIR  H2 jet; embedded cluster
Open questions
o   CO & HCO+: one or two outflows?
o   CH3CN: rotation or expansion?
(?)
 1997: PdBI AB config., 5 antennas, 3mm & 1mm
  H13CO+(1-0); SiO(2-1); CH3CN & CH313CN(12-11)
Results
• SiO  bipolar jet
   – consistent with H2 jet and HCO+ bipolar outflow at high vel.
   – expanding at 100 km/s
• CH3CN  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?
high-velocity



low-velocity
low-velocity
               high-velocity
    Inclination=9°
  Opening ang.=21°
Vexp=100 km/s (R/Rmax)
 1997: PdBI AB config., 5 antennas, 3mm & 1mm
  H13CO+(1-0); SiO(2-1); CH3CN & CH313CN(12-11)
Results
• SiO  bipolar jet
   – consistent with H2 jet and HCO+ bipolar outflow at high vel.
   – expanding at 100 km/s
• CH3CN  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?
             jet



             disk
0.7 arcsec
resolution
Malcolm’s insight:




                      FWHM  R-0.5 
                     Keplerian rotation
   systemic velocity




 FWHM  R-0.5 
Keplerian rotation
dMacc/dt = 10-3 MO/yr
 1997: PdBI AB config., 5 antennas, 3mm & 1mm
  H13CO+(1-0); SiO(2-1); CH3CN & CH313CN(12-11)
Results
• SiO  bipolar jet
    – consistent with H2 jet and HCO+ bipolar outflow at high vel.
    – expanding at 100 km/s
• CH3CN  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?
          In the meanwhile…
• Zhang et al. (1998, 1999): NH3 with VLA
   Keplerian disk (20 MO star); low-velocity
  NH3 in SiO jet
• Hofner et al. (1999): 3.6 cm cont. with VLA
   thermal jet of 1000 AU
• Moscadelli et al.(2000): H2O maser with VLBA
   conical jet over < 300 AU
• Shepherd et al. (2000): 12CO(1-0) with OVRO
   precession of jet/outflow
 2002: PdBI BC config., 6 antennas, 3mm & 1mm
  C34S(2-1) & (5-4); CH3OH(2-1) v=0,1 & (5-4) v=1
Results
• CH3OH  bipolar jet
  – similar to HCO+ low-velocity bipolar outflow
  – precession explains difference between HV and LV flow
• C34S  disk
  – Keplerian rotation about 7 MO star
  – pseudo-Keplerian rotation on larger scales mimics more
    massive star
  – temperature & density gradient in disk
IRAS 20126+4104

  jet in H2 line




                   H2 knots
IRAS 20126+4104

Cesaroni et al. (2005)




Precession model:
opening angle=37°
  Vexp=100 km/s Lebròn et al.
  360°/20000 yr   (2006)
 Precession explains
  difference between
high- and low-velocity
HCO+(1-0) emission!
 2002: PdBI BC config., 6 antennas, 3mm & 1mm
  C34S(2-1) & (5-4); CH3OH(2-1) v=0,1 & (5-4) v=1
Results
• CH3OH  bipolar jet
  – similar to HCO+ low-velocity bipolar outflow
  – precession explains difference between HV and LV flow
• C34S  disk
  – Keplerian rotation about 7 MO star
  – pseudo-Keplerian rotation on larger scales mimics more
    massive star
  – temperature & density gradient in disk
   IRAS 20126+4104
     Cesaroni et al.
      Hofner et al.
                Keplerian
    Moscadelli et al.
                 rotation:
                M*=7 M O




Moscadelli et al. (2005)
       More and more studies…
• Edris et al. (2005): CH3OH & OH with Merlin
   Keplerian rotation (< 20 MO star)
• Sridharan et al. (2005): K, L’, M’ with UKIRT
   disk and binary system (850 AU separation)
• Trinidad et al. (2005): H2O & 1.3cm with VLA
   rotation of H2O maser jet?
• Lebròn et al. (2006): 12CO(2-1) with 30m
   precession of outflow
     IRAS 20126+4104: the picture
• Clump: 1 pc, 400 MO, 40 K
• Outflow/jet: < 0.5 pc, > 64000 yr, 100 km/s,
  8 10-4 MO/yr, precession every 20000 yr
• Keplerian disk: 4 MO, 1500 AU, 150 K,
  > 108 cm-3, T & nH2 gradient, accretion(?) at
  10-3 MO/yr
• (proto)star: 7+/-2 MO, 104 LO
  Best example of circumstellar accretion disk
  in high-mass (proto)star  important
  implications on high-mass star formation
IRAS 20126+4104: the never-ending story

• Is the distance 1.7 kpc???
• Is the clump counter-rotating???
 parallax of 44 GHz CH3OH masers
 merging of C34S Pico Veleta with PdBI
 SiO velocity in precessing jet, H2O maser
  VLBI monitoring, high resolution & sensitivity
  PdBI imaging of CH3CN disk, etc. etc.…
IRAS 20126+4104: the never-ending story

• Is the distance 1.7 kpc???
• Is the clump counter-rotating???
 parallax of 44 GHz CH3OH masers
 merging of C34S Pico Veleta with PdBI
 SiO velocity in precessing jet, H2O maser
  VLBI monitoring, high resolution & sensitivity
  PdBI imaging of CH3CN disk, etc. etc.…
Still a lot to understand…


Malcolm’s tips urgently needed!
 close to star: T > 300 K


far from star: T < 200 K
     Zhang et al. (1998)




Keplerian rotation about 20 MO star
Shepherd et al. (2000)


                         H2 knots
Yao et al. (2000)




        Sridharan et al. (2005)


                    disk
Sridharan et al. (2005)
     jet/outflow structure
                                  SiO HV
cm   H2O   CO(7-6)   HCO+ CH3OH     H2
                           LV     NH3 LV

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:9
posted:12/19/2011
language:English
pages:48