Probing the magnetic field and dust grain properties of two dark clouds L1495 and L1498 through photopolarimetry

Abstract

ABSTRACT We present the R-band polarimetry of two low-latitude Lynd’s clouds L1495 and L1498 acquired with AIMPOL at Aryabhatta Research Institute of Observational Sciences, Nainital, India. The estimated polarization across the regions of L1495 and L1498 is typically in the range of ∼1–5 per cent and the position angle is typically in the range of ∼100°–137° from which we infer the morphologies of the corresponding magnetic field in the envelope region ($\theta_{\rm B}^{\rm env}$). In both clouds, the magnetic fields are found to be aligned with the galactic field (θGP). Due to their close proximity to the galactic plane, we incorporate the values of offset ($\theta _{\rm off} = |\theta _{\rm B}^{\rm env} - \theta _{\rm GP}|$) from this study into our previously established geometrical correlation between the variation in relative orientation with the galactic longitude. We find that the offsets estimated for two clouds L1495 and L1498 in this investigation are consistent with the offsets predicted by our previous study. We also generate the extinction map for the two clouds using the NICE technique, and the extinction structure is found to be analogous to the dust structure at the denser region of the cloud as obtained from the 500 µm dust continuum emission maps of Herschel1 SPIRE. Three distinct cores with high extinction are detected in L1495, and two such cores are also detected in L1498. We also estimate the mean particle density ($\lt n_{\rm H_2}\gt $) at the peripheral region as well as the high extinction cores of the clouds.