Optical linear polarization study towards Czernik 3 open cluster at different spatial scales

TL;DR

This study uses optical polarization observations and multi-wavelength data to analyze dust distribution and polarization properties towards the distant Czernik 3 open cluster, revealing complex dust layering and non-uniform dust distribution.

Contribution

First optical polarization study of Czernik 3 at multiple spatial scales, combining Gaia, WISE, and HI/CO data to map dust layers and distribution.

Findings

Dust is not uniformly distributed over the sky plane.

Czernik 3 is approximately 3.6 kpc away, making it one of the most distant clusters studied in optical polarization.

At least two dust layers are present along the line of sight at ~1 kpc and ~3.4 kpc.

Abstract

We present the optical linear polarization observation of stars towards the core of the Czernik 3 cluster in the Sloan i-band. The data were obtained using the EMPOL instrument on the 1.2 m telescope at Mount Abu Observatory. We study the dust distribution towards this cluster by combining the results from our polarization observations with the data from Gaia EDR3, WISE, and the HI, $^{12}$CO surveys. In addition, we use the polarimetric data of previously studied clusters within 15$^\circ$ of Czernik 3 to understand the large scale dust distribution. The observational results of Czernik 3 show a large range in the degree of polarization, indicating that the dust is not uniformly distributed over the plane of the sky, even on a small scale. The distance to the Czernik 3 is constrained to $3.6\pm0.8$ kpc using the member stars in the core region identified from Gaia EDR3 astrometry. This makes it one of the most distant clusters observed for optical polarization so far. The variation of observed degree of polarization and extinction towards this cluster direction suggests the presence of at least two dust layers along this line of sight at distances of $\sim 1$ kpc and $\sim 3.4$ kpc. There is an indication of the presence of dust in the centre of the cluster, as seen from an increase in the degree of polarization and WISE W4 flux. The large scale distribution of dust reveals the presence of a region of low dust content between the local arm and the Perseus arm.