The Huge Magnetic Toroids in the Milky Way Halo
arXiv:2404.02038 · doi:10.3847/1538-4357/ad3a61
Abstract
The magnetic fields in our Milky Way can be revealed by the distribution of Faraday rotation measures (RMs) of radio sources behind the Galaxy and of radio pulsars inside the Galaxy. Based on the antisymmetry of the Faraday sky in the inner Galaxy to the Galactic coordinates, the magnetic field toroids above and below the Galactic plane with reversed field directions exist in the Galactic halo and have been included in almost all models for the global magnetic structure in the Milky Way. However, the quantitative parameters, such as the field strength, the scale height, and the scale radius of the toroids are hard to determine from observational data. It has long been argued that the RM antisymmetry could be dominated by the local contributions of the interstellar medium. Here we discount the local RM contributions measured by pulsars mostly located within 5 kpc and get the first quantitative estimate of the size of magnetic toroids in the Galactic halo. They are huge, starting from a Galactocentric radius of less than 2 kpc to at least 15 kpc without field direction reversals. Such magnetic toroids in the Galactic halo should naturally constrain the physical processes in galaxies.
14 pages,8 figures
References in corpus (30)
- A New Electron Density Model for Estimation of Pulsar and FRB Distances
- Radio observational constraints on Galactic 3D-emission models
- The FAST Galactic Plane Pulsar Snapshot survey: I. Project design and pulsar discoveries
- Pulsar Rotation Measures and Large-scale Magnetic Field Reversals in the Galactic Disk
- The LOFAR Tied-Array All-Sky Survey (LOTAAS): Survey overview and initial pulsar discoveries
- Magnetic field strength in cosmic web filaments
- Antisymmetry in the Faraday Rotation Sky Caused by a Nearby Magnetized Bubble
- The Faraday Rotation Measure Grid of the LOFAR Two-metre Sky Survey: Data Release 2
- The Thousand-Pulsar-Array program on MeerKAT -- IX. The time-averaged properties of the observed pulsar population
- The FAST Galactic Plane Pulsar Snapshot Survey: II. Discovery of 76 Galactic rotating radio transients and their enigma
- Magnetic field disorder and Faraday effects on the polarization of extragalactic radio sources
- Strong excess Faraday rotation on the Inside of the Sagittarius spiral arm
- Redshift evolution of extragalactic rotation measures
- Detection of a Coherent Magnetic Field in the Magellanic Bridge through Faraday Rotation
- S-PASS/ATCA: a window on the magnetic universe in the southern hemisphere
- A compiled catalog of rotation measures of radio point sources
- RMTable2023 and PolSpectra2023: standards for reporting polarization and Faraday rotation measurements of radio sources
- Constraining the Magnetic Field of the Smith High Velocity Cloud using Faraday rotation
- The Complex Large-scale Magnetic Fields in the First Galactic Quadrant as Revealed by the Faraday Depth Profile Disparity
- The Galactic Plane Infrared Polarization Survey (GPIPS): Data Release 4
- Heightened Faraday Complexity in the inner 1 kpc of the Galactic Centre
- A Radio Polarisation Study of Magnetic Fields in the Small Magellanic Cloud
- A dynamo amplifies the magnetic field of a Milky-Way-like galaxy
- The Southern-sky MWA Rapid Two-metre (SMART) pulsar survey -- I. Survey design and processing pipeline
- Revisiting Rotation Measures from the Canadian Galactic Plane Survey: the Magnetic Field in the Disk of the Outer Galaxy
- Peering into the Milky Way by FAST: III. Magnetic fields in the Galactic halo and farther spiral arms revealed by the Faraday effect of faint pulsars
- The Apertif science verification campaign - Characteristics of polarised radio sources
- Galactic halo bubble magnetic fields and UHECR deflections
- Polarization Measurements of Arecibo-Sky Pulsars: Faraday Rotations and Emission-Beam Analyses
- Distant probes of RM structure -- Where is the Faraday Rotation towards the Magellanic Leading Arm?