Statistical Properties of the Population of the Galactic Center Filaments II: The Spacing Between Filaments

Abstract

We carry out a population study of magnetized radio filaments in the Galactic center using MeerKAT data by focusing on the spacing between the filaments that are grouped. The morphology of a sample of 43 groupings containing 174 magnetized radio filaments are presented. Many grouped filaments show harp-like, fragmented cometary tail-like, or loop-like structures in contrast to many straight filaments running mainly perpendicular to the Galactic plane. There are many striking examples of a single filament splitting into two prongs at a junction, suggestive of a flow of plasma along the filaments. Spatial variations in spectral index, brightness, bending and sharpening along the filaments indicate that they are evolving on a 10^{5-6}-year time scale. The mean spacings between parallel filaments in a given grouping peaks at $\sim 16^{\prime \prime }$. We argue by modeling that the filaments in a grouping all lie on the same plane and that the groupings are isotropically oriented in 3D space. One candidate for the origin of filamentation is interaction with an obstacle, which could be a compact radio source, before a filament splits and bends into multiple filaments. In this picture, the obstacle or sets the length scale of the separation between the filaments. Another possibility is synchrotron cooling instability occurring in cometary tails formed as a result of the interaction of cosmic-ray driven Galactic center outflow with obstacles such as stellar winds. In this picture, the mean spacing and the mean width of the filaments are expected to be a fraction of a parsec, consistent with observed spacing.

53 pages, 32 figures, MNRS (in press)

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Cited by in corpus (9)

• The Population of the Galactic Center Filaments: Position Angle Distribution Reveal a Degree-scale Collimated Outflow from Sgr A* along the Galactic Plane
• Populations of Magnetized Filaments in the Intracluster Medium and the Galactic Center
• The population of Galactic centre filaments III: candidate radio and stellar sources
• Non-thermal filaments and AGN recurrent activity in the galaxy group Nest200047: a LOFAR, uGMRT, MeerKAT, VLA radio spectral analysis
• Spatial intermittency of particle distribution in relativistic plasma turbulence
• Supernova-remnant origin of the Galactic-Centre filaments
• The JWST-NIRCam View of Sagittarius C. II. Evidence for Magnetically Dominated HII Regions in the CMZ
• SOFIA/HAWC+ Far-Infrared Polarimetric Large Area CMZ Exploration Survey. V. The Magnetic Field Strength and Morphology in the Sagittarius C Complex
• The SARAO MeerKAT Galactic Plane Survey filamentary source catalogue