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Massive Star Formation. Observational. Cassandra Fallscheer PhD Advisor: Henrik Beuther Monday 28. March 2007. Grew up in California…close to Paradise. Cal Poly, San Luis Obispo. Studied Physics & Mathematics Spent 2 months on the Golden Bear. Velocity [km/s]. Offset [”].
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Massive Star Formation Observational Cassandra Fallscheer PhD Advisor: Henrik Beuther Monday 28. March 2007
Cal Poly, San Luis Obispo • Studied Physics & Mathematics • Spent 2 months on the Golden Bear
Velocity [km/s] Offset [”] Disks in Massive Star Formation • Two current formation theories 1. scaled-up version of low mass SF 2. coalescence and merging • Should observe accretion disks in 1st scenario IRAS20126+4102,Cesaroni et al. 2005
Accretion Disks • Should see velocity gradient perpendicular to the outflow • Use (sub)mm interferometry • Tracers of high density regions: C34S, CH3CN, N2H+, etc.
Observational difficulties to overcome • Deeply embedded, far away, clustered environment leads to confusion • Distinguish disk emission from the surrounding envelope emission • Appropriate spectral line tracer to detect disk unknown
Interferometers • PdBI • SMA • ALMA 8 x 6m, 500m 6 x 15m, 408m 54 x 12m 12 x 7m, 14km
My Contribution thus far: IRDC 18223-3 • ~3.7 kpc • VLSR~45.3 kms-1 • M~576M with T~15 KM~0.01M with T~51 K • Hydro-simulations predict accretion rates of 10-4Myr-1 IRDC 18223-1243 Beuther, Sridharan, & Saito 2005
My contribution Need to know whereabouts of outflows Beam size: 1.8” x 1.7”
Channel Maps Velocity channel map of C18O44-47 kms-1 (VLSR=45.3)
kms-1 C18O Velocity Moment Map ΔDec. (”) ΔR.A. (”) Moment Maps Outline velocity structure of gas *