On the origin of de‐polarization in CB54

Abstract

We present polarimetric observations of the Bok globule CB54 in the far-infrared via SOFIA/HAWC+ bands D (154 𝜇m) and E (214 𝜇m). We detect polarization with mean polarization degrees of p 154 μm = 7.7 % ± 5.4% and p 214 μm = 8.5 % ± 5.4 % at 154 and 214 𝜇m, respectively. The polarization degree decreases toward the inner region of CB54, revealing a "polarization hole". This finding can be explained by the impact of dichroic absorption counteracting the effect of polarized emission. The same effect allows us to explain the observed wavelength-dependent orientation of the linear polarization in the dense, central region of CB54. The polarization pattern appears uniform at core scales but un-ordered at larger scales-similar to what was found in previous studies of this object. The mean polarization angle amounts to 𝜃 154 μm = 62.4 ± 44.5 • and 𝜃 214 μm = −80.1± 60.0 • at 154 and 214 𝜇m, respectively.