Suzaku Studies of the Supernova Remnant CTB~109 Hosting the Magnetar 1E~2259+586

TL;DR

This study uses Suzaku data to estimate the age of the supernova remnant CTB 109 and magnetar 1E 2259+586, revealing a significant age discrepancy likely due to magnetic field decay, suggesting magnetars are younger than previously thought.

Contribution

The paper provides the first detailed modeling of magnetic field decay in magnetars and highlights the age discrepancy between magnetars and their associated remnants.

Findings

CTB 109 age estimated at ~14 kyr

Magnetar characteristic age is overestimated at 230 kyr

Magnetars are likely much younger objects

Abstract

Ages of the magnetar 1E 2259+586 and the associated supernova remnant CTB~109 were studied. Analyzing the Suzaku data of CTB~109, its age was estimated to be $\sim$14~kyr, which is much shorter than the measured characteristic age of 1E 2259+586, 230 kyr. This reconfirms the previously reported age discrepancy of this magnetar/remnant association, and suggests that the characteristic ages of magnetars are generally over-estimated as compared to their true ages. This discrepancy is thought to arise because the former are calculated without considering decay of the magnetic fields. This novel view is supported independently by much stronger Galactic-plane concentration of magnetars than other pulsars. The process of magnetic field decay in magnetars is mathematically modeled. It is implied that magnetars are much younger objects than previously considered, and can dominate new-born neutron stars.