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Related papers: Bok globule CB17: Polarization, extinction and dis…

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We trace the peripheral magnetic field structure of Bok globule CB130, by estimating the linear polarization of its field stars in the R band. The magnetic field orientation sampled by these stars, aligned on average among themselves and…

Solar and Stellar Astrophysics · Physics 2016-09-07 A. Chakraborty , H. S. Das

We present optical and submillimetre polarimetry data of the Bok globule CB3 and optical polarimetry data of the Bok globule CB246. We use each set of polarimetry data to infer the B-field orientation in each of the clouds. The optical data…

Astrophysics of Galaxies · Physics 2015-05-13 D. Ward-Thompson , A. K. Sen , J. M. Kirk , D. Nutter

The measurement of polarization of the background stars in the region of Bok globules is important to study the magnetic field geometry and dust grain characteristics in the globule. These parameters are important for the formation and…

Instrumentation and Methods for Astrophysics · Physics 2012-06-08 D. Paul , H. S. Das , A. K. Sen

Thanks to their well-defined shape and mostly isolated locations, Bok globules are suitable objects for studying the physics of low-mass star formation. To study the magnetic field of the prototypical Bok globule B335, we obtained a…

Solar and Stellar Astrophysics · Physics 2021-02-03 Niko Zielinski , Sebastian Wolf , Robert Brunngräber

Bok globules are small, dense clouds that act as isolated precursors for the formation of single or binary stars. Although recent dust polarization surveys, primarily with Planck, have shown that molecular clouds are strongly magnetized,…

Using the Submillimeter Common-User Bolometer Array (SCUBA) at the James Clerk Maxwell Telescope (JCMT), we obtained submillimeter polarization maps of the Bok globules B335, CB230, and CB244 at 850micron. We find strongly aligned…

Astrophysics · Physics 2009-11-07 Sebastian Wolf , Ralf Launhardt , Thomas Henning

We present high angular resolution SMA and Spitzer observations toward the Bok globule CB17. SMA 1.3mm dust continuum images reveal within CB17 two sources with an angular separation of about 21" (about 5250 AU at a distance of 250 pc). The…

Solar and Stellar Astrophysics · Physics 2015-06-04 Xuepeng Chen , Hector G. Arce , Michael M. Dunham , Qizhou Zhang , Tyler L. Bourke , Ralf Launhardt , Markus Schmalzl , Thomas Henning

We study the polarization efficiency (defined as the ratio of polarization to extinction) of stars in the background of the small, nearly spherical and isolated Bok globule CB4 to understand the grain alignment process. A decrease in…

Solar and Stellar Astrophysics · Physics 2015-06-17 Ajoy Barman , Himadri Sekhar Das

Polarimetric observations of about 50 stars located in a close vicinity of the Bok globule CB67 having significantly nonspherical shape and rapid rotation are performed. The data obtained are compared with the available observations of this…

Astrophysics of Galaxies · Physics 2014-04-25 M. S. Prokopjeva , A. K. Sen , V. B. Il'in , N. V. Voshchinnikov , R. Gupta

We have observed the large Bok globule CB 54 in 850$\mu$m polarised light using the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT). We find that the magnetic field in the periphery of the globule shows significant, ordered…

Context: The initial conditions for the gravitational collapse of molecular cloud cores and the subsequent birth of stars are still not well constrained. The characteristic cold temperatures (about 10 K) in such regions require observations…

Astrophysics of Galaxies · Physics 2014-09-16 M. Schmalzl , R. Launhardt , A. M. Stutz , H. Linz , T. L. Bourke , H. Beuther , Th. Henning , O. Krause , M. Nielbock , A. Schmiedeke

We report the results of optical polarimetric observations of a Bok globule CB34 to study magnetic field structure on large scales ($10^5-10^6$ AU), which is combined with archival sub-mm observations to characterize the magnetic field…

Solar and Stellar Astrophysics · Physics 2016-11-23 A. Das , H. S. Das , Biman J. Medhi , S. Wolf

We study the influence and structure of the magnetic field in the early phases of low-mass star formation using polarization maps of Bok globules at a wavelength of 850micron, obtained with the Submillimeter Common-User Bolometer Array…

Astrophysics · Physics 2009-11-10 Sebastian Wolf , Ralf Launhardt , Thomas Henning

(abridged for arXiv) We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around…

Distances to Bok globules and small dark nebulae are important for a variety of reasons. We provide new distance estimates to several small clouds, some of them known to harbor YSO and molecular outflows, and thus being of particular…

Astrophysics of Galaxies · Physics 2010-03-15 Jens Knude , Nadia Kaltcheva

Context: The role of magnetic fields in the star formation process is a contentious matter of debate. In particular, no clear observational proof exists of a general influence by magnetic fields during the initial collapse of molecular…

Solar and Stellar Astrophysics · Physics 2014-04-23 Gesa Bertrang , Sebastian Wolf , Himadri S. Das

The distance determination of small Bok globules is often difficult because of its small size and opaqueness. In this work, we determine the distances to six small Bok globules CB 17, CB 24, CB 188, CB 224, CB 230 and CB 240 using near…

Solar and Stellar Astrophysics · Physics 2015-07-15 A. Das , H. S. Das , A. S. Devi

We use 3mm continuum NOEMA and NH$_3$ VLA observations towards the First Hydrostatic Core (FHSC) candidate CB 17 MMS to reveal the dust structure and gas properties down to 600-1,100 au scales and constrain its evolutionary stage. We do not…

Context. Polarimetric observations of Bok globules frequently show a decrease in the degree of polarization towards their central dense regions (polarization holes). This behaviour is usually explained with increased disalignment owing to…

Solar and Stellar Astrophysics · Physics 2016-03-30 R. Brauer , S. Wolf , S. Reissl

We present a detailed theoretical study of the isolated Bok globule CB17 (L1389) based on spectral maps of CS, HCO$^+$, C$^{18}$O, C$^{34}$S, and H$^{13}$CO$^+$ lines. A phenomenological model of prestellar core evolution, a time-dependent…

Astrophysics · Physics 2009-11-11 Ya. Pavlyuchenkov , D. Wiebe , R. Launhardt , Th. Henning
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