CARMA observations of magnetic fields in star-forming filaments · 2020. 1. 1. · CARMA...

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)

3 Chat Hull — IAUS 305: Polarimetry — 4 December 2014

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


Pereyra & Magalhães 2004

10 pc

Musca dark cloud

B-fields in large-scale filaments

Credit: Bill Saxton, NRAO/AUI KALYPSO project, Harvard/CfA


Polarization (dust absorption) ALIGNED DUST GRAINS

BACKGROUND STAR (unpolarized) ORDERED MAGNETIC FIELD


Polarization (dust emission)

ORDERED MAGNETIC FIELD

ALIGNED DUST GRAINS


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


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


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


NGC 1333-IRAS 4A NGC 1333-IRAS 4B, 4B2

TADPOL results

1000 AU 1000 AU

Hull+2014, ApJS, 213, 153


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


TADPOL results

Ser-emb 8, 8(N)

3″

1000 AU

Hull+2014, ApJS, 213, 153


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


CD

F

𝜽𝜽outflow – 𝜽𝜽B-field (deg)

0 1

0º 90º

Hull+ 2014, ApJS, 213, 153


HH 211

Ser-emb 8

OMC3-MMS6

IRAS 4A

Outflow

B-field

HI-POL: B-fields random w.r.t. outflows


VLA 1623 L1527

IRAS 4B

Outflow

B-field

L1551 NE

LO-POL: B-fields ⟂ outflows


Future work with ALMA

Credit: ESO/S. Guisard - http://www.eso.org/public/images/potw1217a/


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?


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


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

http://adsabs.harvard.edu/abs/2014ApJS..213...13H

http://adsabs.harvard.edu/abs/2013ApJ...768..159H

http://www.chathull.com


Fin

CARMA observations of magnetic fields in star-forming filaments · 2020. 1. 1. · CARMA...

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