carma observations of magnetic fields in star-forming filaments · 2020. 1. 1. · carma...
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CARMA observations of magnetic fields in star-forming filaments
Chat Hull Jansky Fellow — Harvard-Smithsonian Center for Astrophysics
National Radio Astronomy Observatory
Session 8 IAUS 305 – Polarimetry Punta Leona, Costa Rica
4 December 2014
Photo: Chat Hull (Harvard/NRAO)
CARMA observations of magnetic fields in protostellar envelopes
Chat Hull Jansky Fellow — Harvard-Smithsonian Center for Astrophysics
National Radio Astronomy Observatory
Session 8 IAUS 305 – Polarimetry Punta Leona, Costa Rica
4 December 2014
Photo: Chat Hull (Harvard/NRAO)
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Outline
• Magnetized star formation
• TADPOL survey – CARMA 1mm full-Stokes polarization system
• B-fields vs. outflows
– Randomly aligned: high-polarization sources – Preferentially ⟂ : low-polarization sources
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Pereyra & Magalhães 2004
10 pc
Musca dark cloud
B-fields in large-scale filaments
Credit: Bill Saxton, NRAO/AUI KALYPSO project, Harvard/CfA
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Polarization (dust absorption) ALIGNED DUST GRAINS
BACKGROUND STAR (unpolarized) ORDERED MAGNETIC FIELD
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Polarization (dust emission)
ORDERED MAGNETIC FIELD
ALIGNED DUST GRAINS
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What is the role of magnetic fields in star formation?
Fundamental? Incidental?
CARMA Combined Array for Research in Millimeter-wave Astronomy
Consortium: Berkeley, Caltech, Illinois, Maryland, Chicago
– 6 ⨯10-m, 9 ⨯ 6-m, and 8 ⨯ 3.5-m telescopes
– Observations at 1 cm, 3 mm, and 1 mm (polarization!)
– Located in Cedar Flat, CA (near Bishop)
Orthomode transducer
SIS mixers
WBA13 I.F. amplifiers
(1-9 GHz)
1 mm dual-polarization receivers
1 inch
Credit: Dick Plambeck
Waveguide circular
polarizer
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TADPOL collaboration
• Harvard/NRAO Chat Hull (PI)
• UC Berkeley
Dick Plambeck, Mel Wright, Carl Heiles
• University of Maryland Marc Pound, Alberto Bolatto, Katherine Jameson, Lee Mundy
• Caltech John Carpenter, James Lamb
• University of Illinois, Urbana-Champaign Leslie Looney, Dick Crutcher
• Other Geoff 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, Nikolaus Volgenau, Nick Hakobian
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TADPOL results
L1157
See also: Stephens+ (incl. C.H.) 2013, ApJL, 769, L15
1000 AU
Hull+2014, ApJS, 213, 153
Credit: Bill Saxton, NRAO/AUI KALYPSO project, Harvard/CfA
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NGC 1333-IRAS 4A NGC 1333-IRAS 4B, 4B2
TADPOL results
1000 AU 1000 AU
Hull+2014, ApJS, 213, 153
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L1527 VLA 1623
See also: Tobin+2012, Nature, 493, 83 (L1527) & Murillo+ 2013, A&A, 560, 103 (VLA 1623)
TADPOL results
1000 AU 1000 AU
Hull+2014, ApJS, 213, 153
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TADPOL results
Ser-emb 8, 8(N)
3″
1000 AU
Hull+2014, ApJS, 213, 153
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Outflow vs. B-field: distribution Simulation: outflows & B-fields aligned within a 20º cone (tightly aligned)
Simulation: outflows & B-fields are randomly oriented
Simulation: outflows & B-fields aligned between 70–90º (preferentially misaligned)
Hull+ 2013, ApJ, 768, 159 (plot updated Feb ‘14)
𝜽𝜽outflow – 𝜽𝜽B-field (deg)
0 1
0º 90º
CD
F
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CD
F
𝜽𝜽outflow – 𝜽𝜽B-field (deg)
0 1
0º 90º
Hull+ 2014, ApJS, 213, 153
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HH 211
Ser-emb 8
OMC3-MMS6
IRAS 4A
Outflow
B-field
HI-POL: B-fields random w.r.t. outflows
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VLA 1623 L1527
IRAS 4B
Outflow
B-field
L1551 NE
LO-POL: B-fields ⟂ outflows
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Future work with ALMA
Credit: ESO/S. Guisard - http://www.eso.org/public/images/potw1217a/
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Ser-emb 6
FUTURE: Cycle 2 ALMA observations
Ser-emb 8, 8(N)
Class 0
CORE POLARIZATION (PI: Hull, high priority)
• 0.36” resolution @ Band 7 (dust pol)
• Also outflow maps (@ Band 6)
• Probing ~150 AU disk scales
• Are B-fields always toroidal?
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FUTURE: Cycle 2 ALMA observations Class II
DISK POLARIZATION (PI: Hull, filler)
• 0.1” resolution @ Band 7 (dust pol) • Probing ~7 AU elements within disk
Credit: ESA/C. Carreau
Credit: Jim Stone (astro.princeton.edu/~jstone/images/3d-disk.gif)
TW Hya
FAKE!
HL Tau ALMA image credit: ALMA (NRAO/ESO/NAOJ); C. Brogan, B. Saxton (NRAO/AUI/NSF)
HL Tau disk polarization with CARMA, see: Stephens+2014, Nature, 514, 597
HL Tau
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TADPOL data release 2014 ApJS, 213, 153
TADPOL outflows vs. B-fields
2013 ApJ, 768, 159
More info tadpol.astro.illinois.edu, chathull.com
(1) Random outflows vs. B-fields
(2) HI-POL: B-fields random w.r.t. outflows
(3) LO-POL: B-fields wrapped by rotation Hull+ 2013, ApJ, 768, 159
Summary
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Fin