Near-Infrared Polarimetry toward the Galactic Center

Shogo Nishiyama; Motohide Tamura; Hirofumi Hatano; Saori Kanai; Mikio Kurita; Shuji Sato; Tetsuya Nagata

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arXiv · 0809.4945

Near-Infrared Polarimetry toward the Galactic Center

Shogo Nishiyama·Motohide Tamura·Hirofumi Hatano·Saori Kanai·Mikio Kurita·Shuji Sato·Tetsuya Nagata

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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.

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Shogo Nishiyama, Motohide Tamura, Hirofumi Hatano, Saori Kanai, Mikio Kurita, Shuji Sato, Tetsuya Nagata. 2008-09-29. Near-Infrared Polarimetry toward the Galactic Center. https://arxiv.org/abs/0809.4945

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