Identification of CXOU J171405.7-381031 as a New Magnetar with XMM-Newton

Abstract

We observed the 3.8 s pulsar CXOU J171405.7$-$381031 with XMM-Newton, and discovered a significant $\dot P$ of 6.40$\ \pm\ $0.05 $\times$ 10$^{-11}\ $s s$^{-1}$ from this source for the first time, with the aid of archival Chandra data. The characteristic age (950 yr), the magnetic field strength (5 $\times$ 10$^{14}\ $G), and the spin-down luminosity (4.5 $\times$ 10$^{34}\ $erg s$^{-1}$) derived from $P$ and $\dot P$ lead us to conclude that CXOU J171405.7$-$381031 should be identified as a new magnetar. The obtained characteristic age indicates that CXOU J171405.7$-$381031 is the youngest among all known anomalous X-ray pulsars, and is consistent with the age estimated from the thermal X-rays of the associated supernova remnant. The ratio between the 2-10 keV luminosity and the spin-down luminosity is almost unity, which implies that CXOU J171405.7$-$381031 is the key source to connect magnetars with traditional radio pulsars.