Counterclockwise Magnetic Fields in the Norma Spiral Arm
نویسندگان
چکیده
Pulsars provide unique probes of the large-scale interstellar magnetic field in the Galactic disk. Up to now, the limited Galactic distribution of the known pulsar population has restricted these investigations to within a few kiloparsec of the Sun. The Parkes multibeam pulsar survey has discovered many more-distant pulsars which enables us for the first time to explore the magnetic field in most of the nearby half of the Galactic disk. Here we report the detection of counterclockwise magnetic fields in the Norma spiral arm using pulsar rotation measures. The fields are coherent in direction over a linear scale of ∼ 5 kpc along the arm and have a strength of −4.4±0.9 μG. The magnetic field between the Carina-Sagittarius and Crux-Scutum arms is confirmed to be coherent from l ∼ 45 to l ∼ 305 over a length of ∼ 10 kpc. These results strengthen arguments for a bisymmetric spiral model for the field configuration in the Galactic disk. Subject headings: ISM: magnetic fields — pulsars: general — Galaxy: structure
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Pulsars provide unique probes for the large-scale interstellar magnetic field in the Galactic disk. The Parkes multibeam pulsar survey has discovered many distant pulsars which enables us for the first time to explore the magnetic field in most of the nearby half of the Galactic disk. The fields are found to be coherent in direction over a linear scale of ∼ 10 kpc between the Carina-Sagittarius...
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