Superposing the Magnetic spiral structure of the Milky Way, on the stellar spiral arms -- Matching the unique galactic magnetic field reversal Zone with two galactic spiral arm Segments

TL;DR

This study maps the Galactic magnetic field reversal zone, revealing its location relative to spiral arms and identifying a magnetic annulus that encompasses segments of two different arms, enhancing understanding of the Milky Way's magnetic structure.

Contribution

It introduces a detailed analysis of the magnetic field reversal zone in the Milky Way, linking it to specific spiral arm segments and providing precise measurements of the annulus width and location.

Findings

Magnetic field reversal annulus is 2.1 +/-0.3 kpc wide.

The annulus encompasses the Crux-Centaurus and Sagittarius arms.

Peak synchrotron emission is about 220 +/-40 pc inside the spiral arm edge.

Abstract

To pinpoint the peak location of the synchrotron total intensity emission in a spiral arm, we use a map of the spiralarm locations (from the observed arm tangent). Thus In a typical spiral arm in Galactic Quadrant I, we find the peak of the synchrotron radiation to be located about 220 +/-40 pc away from the inner arm edge (hot dust lane) inside the spiral arm. While most of the galactic disk has a clockwise largescale magnetic field, we make a statistical analysis to delimitate more precisely the smaller reverse annulus wiith a counterclockwise galactic magnetic field. We find an annulus width of 2.1 +/-0.3 kpc (measured along the Galactic radius), located from 5.5 to 7.6 kpc from the Galactic Center). The annulus does not overlay with a single spiral arm -- it encompasses segments of two different spiral arms. Using a recent delineation of the position of spiral arms, the field-reversed annulus is seen to encompass the Crux-Centaurus arm (in Galactic Quadrant IV) and the Sagittarius arm (in Galactic Quadrant I).