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Polarization in forming stars Probing small scales with carma

Polarization in forming stars Probing small scales with carma. Chat Hull UC Berkeley, Radio Astronomy Laboratory 27 August 2012 NSF CARMA site visit Cedar Flat, CA. Progress overview. Testing: Feb. – Oct., 2010 Tested polarizers, mixers, and orthomode transducers. Progress overview.

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Polarization in forming stars Probing small scales with carma

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  1. Polarization in forming starsProbing small scales with carma 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 IRAS 4A • Commissioning: Oct. 2010 – 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 – • 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 (Bolattoet al.) • Eagle Nebula polarization (Pound et al.) • Protostellar polarization (Kwon et al.) • Saturn polarization (Princeton)

  6. TADPOL survey 28 targets 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 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 ThusharaPillai, John Carpenter, James Lamb, NikolausVolgenau • 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 Credit: Bill Saxton, Harvard-Smithsonian Center for Astrophysics

  9. Misalignment of B-fields and outflows IRAS 4A VLA 1623 IRAS 16293 Rao+ 2009 Holland+ 1996 Outflow Girart+ 2006 B-field

  10. Isolated cores L1157

  11. Isolated cores IRAS 4A IRAS 2A

  12. Isolated cores IRAS 4B Ser-emb8 4B1 4B2

  13. High-mass star-forming regions G034 MM1

  14. High-mass star-forming regions DR 21(OH)

  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 • 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

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