Magnetic Fields toward Ophiuchus-B Derived from SCUBA-2 Polarization Measurements

We present the results of dust emission polarization measurements of Ophiuchus-B (Oph-B) carried out using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on the James Clerk Maxwell Telescope in Hawaii. This work is part of the B-fields in Star-forming Region Observations survey initiated to understand the role of magnetic fields in star formation for nearby star-forming molecular clouds. We present a first look at the geometry and strength of magnetic fields in Oph-B. The field geometry is traced over ∼0.2 pc, with clear detection of both of the sub-clumps of Oph-B. The field pattern appears significantly disordered in sub-clump Oph-B1. The field geometry in Oph-B2 is more ordered, with a tendency to be along the major axis of the clump, parallel to the filamentary structure within which it lies. The degree of polarization decreases systematically toward the dense core material in the two sub-clumps. The field lines in the lower density material along the periphery are smoothly joined to the large-scale magnetic fields probed by NIR polarization observations. We estimated a magnetic field strength of 630 ± 410 μG in the Oph-B2 sub-clump using a Davis–Chandrasekhar–Fermi analysis. With this magnetic field strength, we find a mass-to-flux ratio λ = 1.6 ± 1.1, which suggests that the Oph-B2 clump is slightly magnetically supercritical.

Lei Zhu | A. Scaife | P. Koch | A. Whitworth | N. Peretto | G. Fuller | P. Andre' | H. Chen | T. Onaka | M. Tamura | Sang-Sung Lee | D. Byun | D. Johnstone | P. Bastien | Jongsoo Kim | G. Savini | J. Francesco | B. Matthews | Di Li | P. Friberg | M. Seta | J. Kwon | T. Nagata | Tsuyoshi Inoue | W. Chen | K. Kawabata | S. Eyres | S. Falle | M. Griffin | W. Holland | J. Greaves | G. Moriarty-Schieven | T. Hasegawa | D. Ward-Thompson | J. Hatchell | A. Chrysostomou | J. Fiege | R. Friesen | S. Graves | M. Houde | J. Kirk | J. Richer | K. Lacaille | C. Dowell | A. Kataoka | R. Rao | M. Rawlings | H. Parsons | Jia‐Wei Wang | L. Qian | K. Qiu | T. Ching | Jinghua Yuan | A. Rigby | Jianjun Zhou | Da-lei Li | Miju Kang | Il-Gyo Jeong | H. Nakanishi | Jeong-Eun Lee | Kee-Tae Kim | Hongchi Wang | Tie Liu | Ji-hyun Kang | S. Inutsuka | F. Kemper | Minho Choi | Sung-ju Kang | Jungyeon Cho | H. Yoo | D. Berry | T. Pyo | F. Nakamura | S. Loo | D. Arzoumanian | Guoyin Zhang | Junhao Liu | Y. Doi | J. Robitaille | Chuan-Peng Zhang | Hua-b. Li | Sheng-Yuan Liu | S. Lai | A. Soam | C. Lee | Ya-Wen Tang | Gwanjeong Kim | S. Mairs | Shinyoung Kim | K. Pattle | W. Kwon | E. Chung | A. Pon | S. Hayashi | M. Matsumura | S. Sadavoy | K. Tomisaka | Y. Tsukamoto | Hsi-Wei Yen | N. Ohashi | K. Iwasaki | Yusuke Aso | H. Shinnaga | S. Coudé | E. Drabek-Maunder | T. Gledhill | Mi-Ryang Kim | R. Furuya | C. Eswaraiah | K. Kim | A. Lyo | B. Retter | Mike Chen | I. Han | Hyeseung Lee | Thiem C. Hoang | T. Zenko | Masato I. N. Kobayashi | E. Franzmann | Hong-Li Liu | Q. Gu | Yoshihiro Kanamori | H. Saito | J. Hwang | T. Inoue | S. Lai | Hongli Liu | Chuan-peng Zhang | W. Chen | Ya-wen Tang | P. Andre'

[1]  Lei Zhu,et al.  A First Look at BISTRO Observations of the ρ Oph-A core , 2018, 1804.09313.

[2]  P. Koch,et al.  Polarization Properties and Magnetic Field Structures in the High-mass Star-forming Region W51 Observed with ALMA , 2018, 1801.08264.

[3]  P. Koch,et al.  The JCMT BISTRO Survey: The Magnetic Field Strength in the Orion A Filament , 2017, 1707.05269.

[4]  Martin Houde,et al.  ALMA Observations of Dust Polarization and Molecular Line Emission from the Class 0 Protostellar Source Serpens SMM1 , 2017, 1707.03827.

[5]  A. Goodman,et al.  Unveiling the Role of the Magnetic Field at the Smallest Scales of Star Formation , 2017, 1706.03806.

[6]  Saeko S. Hayashi,et al.  First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt , 2017, 1704.08552.

[7]  L. Hartmann,et al.  THE GOULD’S BELT DISTANCES SURVEY (GOBELINS). I. TRIGONOMETRIC PARALLAX DISTANCES AND DEPTH OF THE OPHIUCHUS COMPLEX , 2016, 1611.06466.

[8]  Giorgio Savini,et al.  POL-2: a polarimeter for the James-Clerk-Maxwell telescope , 2016, Astronomical Telescopes + Instrumentation.

[9]  A. Lazarian,et al.  A UNIFIED MODEL OF GRAIN ALIGNMENT: RADIATIVE ALIGNMENT OF INTERSTELLAR GRAINS WITH MAGNETIC INCLUSIONS , 2016, 1605.02828.

[10]  Jungyeon Cho,et al.  A TECHNIQUE FOR CONSTRAINING THE DRIVING SCALE OF TURBULENCE AND A MODIFIED CHANDRASEKHAR–FERMI METHOD , 2016, 1603.08537.

[11]  J. Hough,et al.  WIDE-FIELD INFRARED POLARIMETRY OF THE ρ OPHIUCHI CLOUD CORE , 2015 .

[12]  J. Pineda,et al.  The JCMT Gould Belt Survey: a quantitative comparison between SCUBA-2 data reduction methods , 2015, 1509.06385.

[13]  John E. Vaillancourt,et al.  Interstellar Dust Grain Alignment , 2015 .

[14]  E. Rosolowsky,et al.  The JCMT Gould Belt Survey: first results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population , 2015, 1502.05858.

[15]  A. Lazarian,et al.  Modelling grain alignment by radiative torques and hydrogen formation torques in reflection nebula , 2014, 1412.0424.

[16]  E. Rosolowsky,et al.  The James Clerk Maxwell telescope Legacy Survey of the Gould Belt: a molecular line study of the Ophiuchus molecular cloud , 2014, 1411.1428.

[17]  G. W. Pratt,et al.  Planck intermediate results. XX. Comparison of polarized thermal emission from Galactic dust with simulations of MHD turbulence , 2014, 1405.0872.

[18]  Astronomy,et al.  On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core , 2014, 1408.5133.

[19]  A. Lazarian,et al.  Grain alignment by radiative torques in special conditions and implications , 2014, 1407.8228.

[20]  M. Wright,et al.  TADPOL: A 1.3 mm SURVEY OF DUST POLARIZATION IN STAR-FORMING CORES AND REGIONS , 2013, 1310.6653.

[21]  David Berry,et al.  SMURF: SubMillimeter User Reduction Facility , 2013 .

[22]  Zhi-Yun Li,et al.  DOES MAGNETIC-FIELD–ROTATION MISALIGNMENT SOLVE THE MAGNETIC BRAKING CATASTROPHE IN PROTOSTELLAR DISK FORMATION? , 2013, 1301.6545.

[23]  P. A. R. Ade,et al.  SCUBA-2: the 10 000 pixel bolometer camera on the James Clerk Maxwell Telescope , 2013, 1301.3650.

[24]  Douglas Scott,et al.  Scuba-2: Iterative map-making with the sub-millimetre user reduction facility , 2013, 1301.3652.

[25]  L. Mundy,et al.  MISALIGNMENT OF MAGNETIC FIELDS AND OUTFLOWS IN PROTOSTELLAR CORES , 2012, 1212.0540.

[26]  P. Koch,et al.  DUST CONTINUUM AND POLARIZATION FROM ENVELOPE TO CORES IN STAR FORMATION: A CASE STUDY IN THE W51 NORTH REGION , 2012, 1212.0656.

[27]  B. Matthews,et al.  SUBMILLIMETER POLARIZATION OF GALACTIC CLOUDS: A COMPARISON OF 350 μm AND 850 μm DATA , 2012, 1204.1378.

[28]  P. Hennebelle,et al.  Protostellar disk formation and transport of angular momentum during magnetized core collapse , 2012, 1203.1193.

[29]  R. Emery,et al.  Herschel -SPIRE observations of the Polaris flare: Structure of the diffuse interstellar medium at the sub-parsec scale , 2010, 1005.2746.

[30]  A. Goodman,et al.  THE ANGULAR MOMENTUM OF MAGNETIZED MOLECULAR CLOUD CORES: A TWO-DIMENSIONAL–THREE-DIMENSIONAL COMPARISON , 2010, 1003.5118.

[31]  Jessie L. Dotson,et al.  350 μm POLARIMETRY FROM THE CALTECH SUBMILLIMETER OBSERVATORY , 2010, 1001.2790.

[32]  P. Hennebelle,et al.  Disk formation during collapse of magnetized protostellar cores , 2009, 0909.3190.

[33]  M. Houde,et al.  MAGNETIC FIELDS AND INFALL MOTIONS IN NGC 1333 IRAS 4 , 2009, 0907.1301.

[34]  P. Koch,et al.  EVOLUTION OF MAGNETIC FIELDS IN HIGH-MASS STAR FORMATION: LINKING FIELD GEOMETRY AND COLLAPSE FOR THE W51 e2/e8 CORES , 2009, 0905.1996.

[35]  Brenda C. Matthews,et al.  THE LEGACY OF SCUPOL: 850 μm IMAGING POLARIMETRY FROM 1997 TO 2005 , 2009 .

[36]  A. Lazarian,et al.  GRAIN ALIGNMENT INDUCED BY RADIATIVE TORQUES: EFFECTS OF INTERNAL RELAXATION OF ENERGY AND COMPLEX RADIATION FIELD , 2008, 0812.4576.

[37]  P. Koch,et al.  EVOLUTION OF MAGNETIC FIELDS IN HIGH MASS STAR FORMATION: SUBMILLIMETER ARRAY DUST POLARIZATION IMAGE OF THE ULTRACOMPACT H ii REGION G5.89−0.39 , 2008, 0812.3444.

[38]  Jessie L. Dotson,et al.  DISPERSION OF MAGNETIC FIELDS IN MOLECULAR CLOUDS. II. , 2008, 0909.5227.

[39]  L. Loinard,et al.  A Preliminary VLBA Distance to the Core of Ophiuchus, with an Accuracy of 4% , 2008, 0801.2192.

[40]  G. Kowal,et al.  Studies of Regular and Random Magnetic Fields in the ISM: Statistics of Polarization Vectors and the Chandrasekhar-Fermi Technique , 2008, 0801.0279.

[41]  D. Padgett,et al.  The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VII. Ophiuchus Observed with MIPS , 2007, 0709.3492.

[42]  E. Ostriker,et al.  Theory of Star Formation , 2007, 0707.3514.

[43]  A. Lazarian,et al.  Radiative torques: analytical model and basic properties , 2007, 0707.0886.

[44]  A. Lazarian,et al.  Tracing Magnetic Fields with Aligned Grains , 2007, 0707.0858.

[45]  N. Peretto,et al.  The initial conditions of star formation in the Ophiuchus main cloud: Kinematics of the protocluster condensations , , 2007, 0706.1535.

[46]  A. Whitworth,et al.  The dust temperatures of the pre-stellar cores in the ρ Oph main cloud and in other star-forming regions: consequences for the core mass function , 2007, 0705.2941.

[47]  A. Lazarian,et al.  Radiative torque alignment: essential physical processes , 2007, 0707.3645.

[48]  Ramprasad Rao,et al.  Magnetic Fields in the Formation of Sun-Like Stars , 2006, Science.

[49]  Jongsoo Kim,et al.  The Virial Balance of Clumps and Cores in Molecular Clouds , 2006, Proceedings of the International Astronomical Union.

[50]  Ryo Kandori,et al.  SIRPOL: a JHKs-simultaneous imaging polarimeter for the IRSF 1.4-m telescope , 2006, SPIE Astronomical Telescopes + Instrumentation.

[51]  John E. Vaillancourt,et al.  Placing Confidence Limits on Polarization Measurements , 2006, astro-ph/0603110.

[52]  A. Lazarian,et al.  Grain Alignment by Radiation in Dark Clouds and Cores , 2005, astro-ph/0505571.

[53]  L. Rebull,et al.  Stellar Rotation in Young Clusters: The First 4 Million Years , 2004 .

[54]  R. Crutcher.  What Drives Star Formation? , 2003 .

[55]  Zhi-Yun Li,et al.  Collapse of Magnetized Singular Isothermal Toroids. II. Rotation and Magnetic Braking , 2003, astro-ph/0311377.

[56]  S. Wolf,et al.  Magnetic Field Evolution in Bok Globules , 2003, astro-ph/0303652.

[57]  B. Matthews,et al.  Magnetic Fields in Star-forming Molecular Clouds. V. Submillimeter Polarization of the Barnard 1 Dark Cloud , 2002, astro-ph/0205328.

[58]  J. Girart,et al.  Interferometric Mapping of Magnetic Fields in Star-forming Regions. II. NGC 2024 FIR 5 , 2001, astro-ph/0110682.

[59]  T. Henning,et al.  Measurements of the Magnetic Field Geometry and Strength in Bok Globules , 2001 .

[60]  M. Norman,et al.  Magnetic Field Diagnostics Based on Far-Infrared Polarimetry: Tests Using Numerical Simulations , 2001, astro-ph/0103286.

[61]  James M. Stone,et al.  Density, Velocity, and Magnetic Field Structure in Turbulent Molecular Cloud Models , 2000, astro-ph/0008454.

[62]  D. Johnstone,et al.  Large-Area Mapping at 850 Microns. II. Analysis of the Clump Distribution in the ρ Ophiuchi Molecular Cloud , 2000 .

[63]  Jessie L. Dotson,et al.  Far-Infrared Polarimetry of Galactic Clouds from the Kuiper Airborne Observatory , 2000 .

[64]  R. Klessen,et al.  Control of star formation by supersonic turbulence , 2000, astro-ph/0301093.

[65]  B. Matthews,et al.  Magnetic Fields in Star-forming Molecular Clouds. I. The First Polarimetry of OMC-3 in Orion A , 1999, astro-ph/9911148.

[66]  Telemachos Ch. Mouschovias,et al.  Magnetic Fields and Star Formation: A Theory Reaching Adulthood , 1999 .

[67]  Telemachos Ch. Mouschovias,et al.  in The Origin of Stars and Planetary Systems , 1999 .

[68]  M. Wright,et al.  High-Resolution Millimeter-Wave Mapping of Linearly Polarized Dust Emission: Magnetic Field Structure in Orion , 1998, astro-ph/9805288.

[69]  A. Goodman,et al.  The Polarizing Power of the Interstellar Medium in Taurus , 1998, astro-ph/9803199.

[70]  Jessie L. Dotson,et al.  Polarization of the Far-Infrared Emission from M17 , 1995 .

[71]  F. Shu,et al.  Collapse of Magnetized Molecular Cloud Cores. II. Numerical Results , 1993 .

[72]  T. Mouschovias,et al.  Ambipolar diffusion and star formation : formation and contraction of axisymmetric cloud cores. II: Results , 1993 .

[73]  W. Press,et al.  The time delay of gravitational lens 0957+561. II: Analysis of radio data and combined optical-radio analysis , 1992 .

[74]  B. Wilking.  Star Formation in the Ophiuchus Molecular Cloud Complex , 1992 .

[75]  J. Stutzki,et al.  High spatial resolution isotopic CO and CS observations of M17 SW - The clumpy structure of the molecular cloud core , 1989 .

[76]  F. Adams,et al.  Star Formation in Molecular Clouds: Observation and Theory , 1987 .

[77]  Giles A Novak,et al.  Detection of submillimeter polarization in the Orion nebula , 1984 .

[78]  W. Cudlip,et al.  Far infrared polarimetry of W51A and M42 , 1982 .

[79]  F. Vrba,et al.  Magnetic field structure in the vicinity of five dark cloud complexes. , 1976 .

[80]  A. Z. Dolginov,et al.  Orientation of cosmic dust grains , 1976 .

[81]  Enrico Fermi,et al.  Magnetic fields in spiral arms , 1953 .

[82]  L. Davis,et al.  The Strength of Interstellar Magnetic Fields , 1951 .

[83]  W. A. Hiltner.  On the Presence of Polarization in the Continuous Radiation of Stars. II. , 1949 .

[84]  W. A. Hiltner,et al.  Polarization of Light From Distant Stars by Interstellar Medium. , 1949, Science.

[85]  J S Hall,et al.  Observations of the Polarized Light From Stars. , 1949, Science.