Supernova-remnant origin of the Galactic-Centre filaments

Abstract

ABSTRACT The mechanism to produce the numerous Galactic-Centre filaments (GCFs) that vertically penetrate the Galactic plane without clear evidence of connection to the disc remains a mystery. Here, we show that the GCFs are explained by relics of supernova remnants (rSNRs) driven by hundreds of supernovae (SNe) that exploded in the star-forming ring of the central molecular zone at an SN rate of ∼2 × 10−4 yr−1 in the past ∼0.5 Myr. The evolution of rSNRs is simulated by the propagation of fast-mode magnetohydrodynamic waves, which are shown to converge around the Galactic rotation axis by the focusing effect. Tangential projection of the cylindrical wavefronts on the sky constitutes the vertical filaments. The SNR model explains not only the morphology, but also the non-thermal radio spectrum, smoothed brightness over the distribution area consistent with the Σ–D relation of SNR, and the heating mechanism of hot plasma. We discuss the implication of the SNR model on the study of the interstellar physics in the Galactic Centre and star-formation activity.