Massive Star FormationMassive Star FormationObservationalObservational

Cassandra Fallscheer

PhD Advisor: Henrik Beuther

Monday 28. March 2007

Grew up in California…close to Grew up in California…close to ParadiseParadise

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

My contributionMy contribution

Need to know whereabouts of outflows

Beam size: 1.8” x 1.7”

Channel MapsChannel Maps

Velocity channel map of C18O44-47 kms-1 (VLSR=45.3)

Moment MapsMoment Maps

kms-1

ΔR.A. (”)

ΔD

ec.

(”)

C18O Velocity Moment Map Outline velocity structure of gas

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