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CARMA observations of magnetic fields in star-
forming filaments
Chat HullJansky Fellow —Harvard-Smithsonian Center for Astrophysics
National Radio Astronomy Observatory
AAS 225Session 110: Star Formation ISeattle, WA
5 January 2015
Photo: Chat Hull (Harvard/NRAO)
2Chat Hull – AAS Seattle – 5 January 2015
TADPOL collaboration
• UC BerkeleyChat Hull (PI), Dick Plambeck, Mel Wright, Carl Heiles
• University of MarylandMarc Pound, Alberto Bolatto, Katherine Jameson, Lee Mundy
• CaltechJohn Carpenter, James Lamb, Nikolaus Volgenau
• University of Illinois, Urbana-ChampaignLeslie Looney, Dick Crutcher, Nick Hakobian
• OtherGeoff Bower (ASIAA), Thushara Pillai (Bonn), Dan Marrone (Arizona), Meredith Hughes (Wesleyan), John Vaillancourt & Göran Sandell (USRA-SOFIA), John Tobin (NRAO), Ian Stephens (BU), Jason Fiege & Erica Franzmann (Manitoba), Martin Houde (UWO, Caltech), Brenda Matthews (NRC-CNRC), Woojin Kwon (SRON)
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Outline
• Brief filamentary introduction
• Magnetized filaments– High-mass: NGC 7538– Low-mass: Ser-emb 8, 8(N)
• Simulations
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Pereyra & Magalhães 2004
10
pc
E,B
Musca dark cloud
B-fields in large-scale filaments
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How do different kinds of filaments form?Low- vs. high-mass objects
Large vs. small scales
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High-mass star-forming regionNGC 7538
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NGC 7538
Fallscheer+2013
10 pc
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NGC 7538
Wright, Hull+2014, ApJ, 796, 112
0.1 pc
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Frau+2014
NGC 75380.1 pc
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NGC 7538
Hull+2014, ApJS, 213, 13
0.1 pc
0.1 pc
Small-scale B-field in filament doesn’t reflect original field
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NGC 7538
Frau+2014
0.1 pc
Magnetized filament is shaped by a combination of infall and outflow
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Low-mass star-forming cores
Ser-emb 8, 8(N)
13Chat Hull – AAS Seattle – 5 January 2015
Ser-emb 8, 8(N)
Hull+2014, ApJS, 213, 13
• This filament is small! (d ~ 0.01 pc)
• How did this filament form?
• What does the B-field look like between the cores?
0.01 pc
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1 pc
Summary (1/2)
Chen & Ostriker 2014
Soler+2013
Simulations &
observations
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Summary (2/2)• Comparison of new dust polarization data with multi-scale,
observable MHD simulations will show which processes dominate at small scales
• High-mass: B-fields in filaments may not reflect original configuration, and can be created by outflows, infall, etc.
• Low-mass: numerous formation scenarios. But what about the smallest scales?
• Even higher resolution ALMA observations will clear up (or further complicate?!) the situation
NGC 7538 filament2014 ApJ, 796, 112
TADPOL data release2014 ApJS, 213, 153
TADPOL outflows/B-fields: ApJ, 768, 159
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Fin