Near-IR Polarimetry Around 30 Doradus: I. Separation of the Galactic Sources

TL;DR

This study uses near-infrared polarimetry to distinguish between Galactic foreground sources and LMC sources in a region around 30 Doradus, revealing differences in their polarimetric properties based on proper motion data.

Contribution

It introduces a method to separate Galactic and LMC sources using combined polarimetric and proper motion data in the near-infrared.

Findings

Proper motion groups show distinct polarimetric properties.

Polarimetry can effectively differentiate Galactic from LMC sources.

Statistical analysis supports the separation method.

Abstract

A 20 arcmin \times 20 arcmin region around 30 Doradus in the Large Magellanic Cloud (LMC) is observed and analyzed in the near-infrared. We obtain polarimetry data in the J, H, and K_s bands using the SIRIUS polarimeter SIRPOL at the Infrared Survey Facility 1.4 m telescope. We measure the Stokes parameters of 2562 point-like sources to derive the degree of polarization and the polarization position angles. We discuss the statistics of the groups classified by color-magnitude diagram and proper motions of the sources, in order to separate the Galactic foreground sources from those present in the LMC. We notice that groups classified by the proper motion data show a tendency towards different polarimetric properties.