Linear polarization study of open clusters towards the anticenter direction: Signature of the spiral arms

Abstract

Our objective is to investigate the distribution of dust and associated large-scale structures of the Galaxy using optical linear polarization measurements of various open clusters located at different distances in the Galactic anticenter direction. We present R-band linear polarization observations of stars towards five open clusters: Kronberger~1, Berkeley~69, Berkeley~71, Berkeley~19, and King~8 in the anticenter direction. The polarization observations were carried out using AIMPOL instrument mounted on the 104 cm Sampurnanand telescope of ARIES, Nainital, making it the first study to target the polarization observations towards distant clusters ($\sim$6~kpc). We combined the observed polarization data with the distance information from the Gaia space telescope to infer the dust distribution along the line of sight. The variation in the degree of polarization and extinction with distance reveals the presence of multiple dust layers along each cluster direction. In addition, common foreground dust layers detected towards different cluster directions highlight the presence of global features such as spiral arms. Our results show that the dust clouds at 2~kpc towards Berkeley~69 and Berkeley~71 coincide with the Perseus arm, while the dust layer at $\sim$4~kpc towards distant clusters, Berkeley~19 and King~8, indicates the presence of the Outer arm. The large-scale dust distribution obtained by combining our polarization results with the previous polarization studies of nearby open clusters suggests that the anticenter direction is characterized by low extinction, homogeneous dust distribution with somewhat uniform orientation of the plane-of-sky component of the magnetic field along the line of sight. Our study demonstrates the utility of polarization as a tool to study the large-scale dust distribution.

22 Pages, 14 Figures, 7 Tables, Accepted for publication in Astronomy & Astrophysics Journal

References in corpus (17)

• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Gaia-2MASS 3D maps of Galactic interstellar dust within 3 kpc
• Improving the open cluster census. II. An all-sky cluster catalogue with Gaia DR3
• Updated Gaia-2MASS 3D maps of Galactic interstellar dust
• Evolution of the local spiral structure of the Milky Way revealed by open clusters
• Optical polarimetric study of open clusters: Distribution of Interstellar matter towards NGC 654
• Modelling interstellar extinction and polarization with spheroidal grains
• The Galactic Plane Infrared Polarization Survey (GPIPS): Data Release 4
• The first degree-scale starlight-polarization-based tomography map of the magnetized interstellar medium
• Warp and flare of the old Galactic disc as traced by the red clump stars
• Polarization, Polarizing Efficiency, and Grain alignment towards the direction of the cluster NGC 2345
• Optical Linear Polarization toward the Open Star Cluster Casado Alessi 1
• Broadband Linear Polarization in the Region of the Open Star Cluster NGC 1817
• Revealing the dust grain polarization properties as a function of extinction and distance towards NGC 1893
• A Comparative Study of Dust Grain Polarisation Efficiencies in the Interstellar and Intracluster Mediums towards Anti-Center Galaxy