Investigating the extinction and magnetic field geometry in the Bok globule CB26

ABSTRACT This study investigates the extinction properties, dust distribution, and magnetic field characteristics of the CB26 cloud. Extinction mapping, derived from near-infrared photometry, reveals a good correlation with the dust distribution, as traced by Herschel1SPIRE 500 $\mu\mathrm{ m}$ data, indicating a close link between dust and extinction. The derived column density estimates align with previous Herschel studies. Our optical polarization observations of CB26 reveal a well-aligned magnetic field in the cloud’s low-density envelope, closely following the Galactic plane. In contrast, our reanalysis of archival submillimetre polarization data of CB26 suggests a distinct magnetic field orientation within the cloud core. The offset angle between the core and Galactic magnetic fields is approximately 90$^\circ$, suggesting a decoupling of the core’s magnetic field from the large-scale Galactic field. A relationship is found between polarization rate and distance for 24 field stars in CB26, suggesting that most of the polarization is contributed by dust within 600 pc along the line of sight.