An assessment of the newest magnetar-SNR associations

TL;DR

This paper evaluates the associations between magnetars and supernova remnants, proposing a model where magnetic field growth influences SNR evolution, leading to revised age estimates consistent with recent observations.

Contribution

It introduces a self-consistent model of magnetic field growth in magnetars that affects SNR dynamics and association age estimates, supporting recent observational data.

Findings

Low age estimates for specific magnetar-SNR pairs.

Predicted magnetic field growth aligns with observed spin-down rates.

Modified SNR evolution models explain associations with young magnetars.

Abstract

Anomalous X-ray Pulsars and Soft-Gamma Repeaters groups are magnetar candidates featuring low characteristic ages ($\tau = {P\over{2 {\dot P}}}$). At least some of them they should still be associated with the remnants of the explosive events in which they were born, giving clues to the type of events leading to their birth and the physics behind the apparent high value of the magnetar magnetic fields. To explain the high values of $B$, a self-consistent picture of field growth also suggests that energy injection into the SNR is large and unavoidable, in contrast with the evolution of {\it conventional} SNR. This modified dynamics, in turn, has important implications for the proposed associations. We show that this scenario yields low ages for the new candidates CXOU J171405.7-381031/CTB 37B and XMMU J173203.3-344518/G353.6-0.7, and predicted values agree with recently found ${\dot P}$, giving support to the overall picture.