1. Polarization in forming stars Probing small scales with carma
Star formation regions
Chat Hull
UC Berkeley, Radio Astronomy Laboratory
27 August 2012
NSF CARMA site visit
Cedar Flat, CA

2. Progress overview Testing: Feb. – Oct., 2010
Tested polarizers, mixers, and orthomode transducers

3. Progress overview Installation: Oct. 2010
Installed dual-polarization modules on all 15 six- and ten-meter antennas
1 inch

4. Progress overview Commissioning: Oct. 2010 – Oct. 2011
IRAS 4A
Commissioning: Oct – Oct. 2011
Jan. 2011: first dual-polarization data (Orion)
Feb. 2011: full-Stokes correlator completed
May 2011: first full-Stokes data (IRAS 4A)
May 2011: XY phase calibration method developed
Oct. – Nov. 2011: commissioning data taken

5. Progress overview Science: Feb. 2012 – The TADPOL key project
Full-Stokes system available to outside users
The TADPOL key project
Goals
To understand the role of B-fields in star formation – in the collimation of bipolar outflows, in particular
Understand the importance of B-fields from large to small scales
Results
20 sources mapped
17 detections at 3-sigma or higher; some as high as 30-sigma!
Other polarization projects
M82 polarization (Bolatto et al.)
Eagle Nebula polarization (Pound et al.)
Protostellar polarization (Kwon et al.)
Saturn polarization (Princeton)
-Houde, Hildebrand, etc.: measuring strength of B-field from scatter in vectors
-Illinois folks: L1157 comparison with SHARP data
-Jameson: MIMIR data (Dan Clemens) to look at polarization via IR absorption in tenuous outer layers of clouds

6. TADPOL survey 28 targets 280 observing hours 1 – 4" resolution
Triples number of low-mass, forming stars published to date
280 observing hours
CARMA C, D, & E arrays
1 – 4" resolution
10⨉ higher resolution than CSO & JCMT
Probes intermediate region between ~1 pc (single-dish) and ~100 AU (ALMA)
1 mm wavelength
Ideal for dust polarization, as well as CO(2-1)

7. TADPOL collaboration UC Berkeley University of Maryland Caltech
Chat Hull (PI), Dick Plambeck, Meredith Hughes, Mel Wright, Carl Heiles, Geoff Bower
University of Maryland
Marc Pound, Alberto Bolatto, Katherine Jameson, Lee Mundy
Caltech
Thushara Pillai, John Carpenter, James Lamb, Nikolaus Volgenau
University of Illinois, Urbana-Champagne
Ian Stephens, Leslie Looney, Woojin Kwon, Dick Crutcher, Nick Hakobian
University of Chicago
Roger Hildebrand
Other
Jason Fiege (Manitoba), Erica Franzmann (Manitoba), Martin Houde (UWO, Caltech), Dan Marrone (Arizona), Brenda Matthews (NRC-CNRC), John Vaillancourt (USRA-SOFIA)

8. Canonical model of SF with B-fields
-Note 0º between rotation/outflow axis, and poloidal component of B-field
-The is problematic when it comes to forming rotationally-supported disks (Hennebelle & Ciardi ’09)
Credit: Bill Saxton, Harvard-Smithsonian Center for Astrophysics

9. Misalignment of B-fields and outflows
IRAS 4A
Girart+ 2006
VLA 1623
IRAS 16293
Holland+ 1996
Rao+ 2009
ROTATION: IRAS has rot/grav < 0.1; IRAS4A seems the same (barely any rotation); VLA 1623 questionable (probably slow)
-Holland: JCMT data
-Rao, Girart: SMA
-This is okay, according to Hennebelle & Ciardi ‘09 (easier to form disks with obliquity!)
-Ward-Thompson et al (2009) saw a 30 deg offset between short axes of cores and their polarization directions…another problem!
Outflow
B-field

10. Isolated cores L1157 NEARBY SF regions:
-Perseus (NGC 1333, L1448, SVS13): 235 pc (masers in SVS13)  03:30 LST
-Taurus (DG Tau, L1527): 140 pc  04:30 LST
-Orion: 400 pc  05:30 LST
-Serpens: 415 pc  18:30 LST
-Ophiuchus: 140 pc  17:00 LST
-Cepheus (L1157): 250 pc  22:00 LST
-Isolated (B335, Bok globule): 250 pc

11. Isolated cores IRAS 4A IRAS 2A NEARBY SF regions:
-Perseus (NGC 1333, L1448, SVS13): 235 pc (masers in SVS13)  03:30 LST
-Taurus (DG Tau, L1527): 140 pc  04:30 LST
-Orion: 400 pc  05:30 LST
-Serpens: 415 pc  18:30 LST
-Ophiuchus: 140 pc  17:00 LST
-Cepheus (L1157): 250 pc  22:00 LST
-Isolated (B335, Bok globule): 250 pc

12. Isolated cores IRAS 4B Ser-emb 8 4B1 4B2 NEARBY SF regions:
-Perseus (NGC 1333, L1448, SVS13): 235 pc (masers in SVS13)  03:30 LST
-Taurus (DG Tau, L1527): 140 pc  04:30 LST
-Orion: 400 pc  05:30 LST
-Serpens: 415 pc  18:30 LST
-Ophiuchus: 140 pc  17:00 LST
-Cepheus (L1157): 250 pc  22:00 LST
-Isolated (B335, Bok globule): 250 pc
4B2

13. High-mass star-forming regions
G034 MM1
NEARBY SF regions:
-Perseus (NGC 1333, L1448, SVS13): 235 pc (masers in SVS13)  03:30 LST
-Taurus (DG Tau, L1527): 140 pc  04:30 LST
-Orion: 400 pc  05:30 LST
-Serpens: 415 pc  18:30 LST
-Ophiuchus: 140 pc  17:00 LST
-Cepheus (L1157): 250 pc  22:00 LST
-Isolated (B335, Bok globule): 250 pc

14. High-mass star-forming regions
DR 21(OH)
NEARBY SF regions:
-Perseus (NGC 1333, L1448, SVS13): 235 pc (masers in SVS13)  03:30 LST
-Taurus (DG Tau, L1527): 140 pc  04:30 LST
-Orion: 400 pc  05:30 LST
-Serpens: 415 pc  18:30 LST
-Ophiuchus: 140 pc  17:00 LST
-Cepheus (L1157): 250 pc  22:00 LST
-Isolated (B335, Bok globule): 250 pc

15. Outflow vs. B-field: distribution
Simulation: outflows & B-fields aligned within a 20º cone (takes into account projection effects)
Simulation: outflows & B-fields are randomly oriented
KS test results:
20º cone ruled out (p-value ~ 10-6)
Random orientations cannot be ruled out (p-value ~ 0.5)
Hull+ 2012, in prep.

16. Conclusions Hardware status TADPOL survey status
CARMA polarization system is fully functional
TADPOL survey status
~50% complete; should be complete by winter ‘12
Polarization science status
Full-Stokes system available to entire community
Several polarization projects in progress
TADPOL: L1157 & outflow-vs.-B-field papers in prep.

17. Fin