Near-Infrared Polarimetry toward the Galactic Center

TL;DR

This study uses near-infrared polarimetry to map the magnetic field structure at the Galactic center, revealing a toroidal magnetic configuration consistent with far-infrared/submillimeter observations.

Contribution

It demonstrates that near-infrared polarimetry, after foreground subtraction, effectively probes the magnetic field structure at the Galactic center.

Findings

Magnetic field is aligned toroidally, nearly parallel to the Galactic plane.

Polarization angles peak around 20 degrees, indicating a toroidal magnetic configuration.

Results agree with previous far-infrared/submillimeter observations.

Abstract

Near-infrared polarimetry of point sources reveals the presence of a toroidal magnetic field in the central 20' x 20' region of our Galaxy. Comparing the Stokes parameters between high extinction stars and relatively low extinction ones, we have obtained a polarization originating from magnetically aligned dust grains at the central region of our Galaxy of at most 1-2 kpc. The derived direction of the magnetic field is in good agreement with that obtained from far-infrared/submillimeter observations, which detect polarized thermal emission from dust in the molecular clouds at the Galactic center. Our results show that by subtracting foreground components, near-infrared polarimetry allows investigation of the magnetic field structure at the Galactic center. The distribution of the position angles shows a peak at around 20deg, nearly parallel to the direction of the Galactic plane, suggesting a toroidal magnetic configuration.