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

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

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

Progress overview Commissioning: Oct. 2010 – Oct. 2011 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

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

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)

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)

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

Misalignment of B-fields and outflows IRAS 4A Girart+ 2006 VLA 1623 IRAS 16293 Holland+ 1996 Rao+ 2009 ROTATION: IRAS 16293 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

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

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

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

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

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

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.

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.

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