Massive Star FormationMassive Star FormationObservationalObservational
Cassandra Fallscheer
PhD Advisor: Henrik Beuther
Monday 28. March 2007
Cal Poly, San Luis ObispoCal Poly, San Luis Obispo
• Studied Physics & Studied Physics & MathematicsMathematics
• Spent 2 months on Spent 2 months on the Golden Bearthe Golden Bear
Disks in Massive Star Disks in Massive Star FormationFormation• Two current Two current
formation theoriesformation theories 1. scaled-up 1. scaled-up version version of low of low mass SFmass SF 2. coalescence 2. coalescence and and mergingmerging
• Should observe Should observe accretion disks in 1accretion disks in 1stst scenarioscenario Offset [”]
Velo
city
[km
/s]
IRAS20126+4102, Cesaroni et al. 2005
Accretion DisksAccretion Disks
• Should see velocity Should see velocity gradient gradient perpendicular to the perpendicular to the outflowoutflow
• Use (sub)mm Use (sub)mm interferometryinterferometry
• Tracers of high Tracers of high density regions: Cdensity regions: C3434S, S, CHCH33CN, NCN, N22HH++, etc., etc.
Observational difficulties to Observational difficulties to overcomeovercome
• DDeeply embedded, far away, clustered environment leads to confusion
•Distinguish disk emission from the surrounding envelope emission
•Appropriate spectral line tracer to detect disk unknown
InterferometersInterferometers
• PdBIPdBI
• SMASMA
• ALMAALMA
6 x 15m, 408m
8 x 6m, 500m
54 x 12m 12 x 7m, 14km
My Contribution thus far: My Contribution thus far: IRDC 18223-3IRDC 18223-3
• ~3.7 kpc~3.7 kpc
• VVLSRLSR~45.3 kms~45.3 kms-1-1
• M~576MM~576M with T~15 K with T~15 KM~0.01MM~0.01M with T~51 K with T~51 K
• Hydro-simulations predict Hydro-simulations predict accretion rates of 10-accretion rates of 10-4M4Myr-1yr-1
IRDC 18223-1243 Beuther, Sridharan, & Saito 2005
Moment MapsMoment Maps
kms-1
ΔR.A. (”)
ΔD
ec.
(”)
C18O Velocity Moment Map Outline velocity structure of gas
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