Study of magnetic field geometry and extinction in Bok globule CB130

Abstract

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 the polarization produced within the cloud has a different direction from that of Galactic plane with an offset of 53${}^{\circ }$. The offset between minor axis and the mean magnetic field of CB130 is found to be 80${}^{\circ }$. The estimated strength of the magnetic field in the plane-of-the-sky is $\sim$ 116$\pm$19 $\mu$G. We constructed the visual extinction map using Near Infrared Color Excess (NICE) method to see the dust distribution around CB130. Contours of Herschel {Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA} SPIRE 500$\mu$m dust continuum emission maps of this cloud is over-plotted on the visual extinction map which shows the regions having higher optical extinction corresponds to higher densities of dust. Three distinct high dust density cores (named as C1, C2, and C3) are identified in the extinction map. It is observed that the cores C1 and C3 located close to two previously known cores CB130-1 and CB130-2 respectively. Estimate of visual extinction of some moderately obscured stars of CB130 are made utilizing near-infra red photometry. Its observed that there is a feeble dependence of polarization on extinction; and polarization efficiency (defined as $\text{p}$/A$V$) of the dust grains decreases with the increase in extinction.

Accepted in Astrophysics and Space Science journal (14 pages, 5 figures, 3 tables)

References in corpus (14)

• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• NICEST, a near-infrared color excess method tailored for small-scale structures
• Grain Alignment by Radiative Torques in Special Conditions and Implications
• Optical polarimetry toward the Pipe nebula: Revealing the importance of the magnetic field
• The Earliest Phases of Star formation observed with Herschel (EPoS): The dust temperature and density distributions of B68
• On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core
• The Structure of Molecular Clouds: I - All Sky Near Infrared Extinction Maps
• Grain Alignment in Starless Cores
• Large-scale magnetic fields in Bok globules
• Modeling Grain Alignment by Radiative Torques and Hydrogen Formation Torques in Reflection Nebula
• A method to determine distances to molecular clouds using near-IR photometry
• Study of background star polarization and polarization efficiency of three selected Bok globules CB56, CB60 and CB69
• A Catalog of Background Stars Reddened by Dust in the Taurus Dark Clouds
• Study of grain alignment efficiency and a distance estimate for small globule CB4

Cited by in corpus (4)

• Bok globule CB17: Polarization, extinction and distance
• The relative orientation between local magnetic field and Galactic plane in low latitude dark clouds
• Magnetic field geometry of the large globule CB 34
• A Survey of Magnetic Field Properties in Bok Globules