An Energetic Magnetar in HESS J1713-381/CTB 37B

TL;DR

This paper reports the discovery of a young, energetic magnetar in the supernova remnant CTB 37B, with implications for TeV gamma-ray emission and magnetar properties.

Contribution

It provides the first detailed timing and spectral analysis of the magnetar CXOU J171405.7-381031, linking it to TeV emission and suggesting its energetic role in the SNR.

Findings

Magnetar has a magnetic field of 4.8×10^14 G.

Spin-down power is among the highest for magnetars.

Possible contribution of the magnetar to the TeV emission.

Abstract

We obtained a second Chandra timing measurement of the 3.82 s pulsar CXOU J171405.7-381031 in the supernova remnant (SNR) CTB 37B, which shows that it is spinning down rapidly. The average period derivative of (5.88+/-0.08)E-11 over the 1 year time span corresponds to a dipole magnetic field strength B = 4.8E14 G, well into the magnetar range. The spin-down power E-dot = 4.2E34 erg/s is among the largest for magnetars, and the corresponding characteristic age Tau = P/2P-dot = 1030 years is comparable to estimates of the age of the SNR. The period derivative enables us to recover probable pulsations in an ASCA observation taken in 1996, which yields a mean characteristic age of 860 years over the longer 13 year time span. The source is well detected up to 10 keV, and its composite spectrum is typical of a magnetar. CTB 37B hosts HESS J1713-381, the first TeV source that is coincident with a magnetar. While the TeV emission has been attributed to the SNR shell, it is possibly centrally peaked, and we hypothesize that this particularly young, energetic magnetar may contribute to the HESS source. We also searched for pulsations from another source in a HESS SNR, XMMU J173203.3-344518 in HESS J1731-347/G353.6-0.7 but could not confirm pulsations or long-term flux variability, making it more likely that this source is a weakly magnetized central compact object.