Using the Chandra X-ray Observatory , we have pinpointed the location of a faint X-ray point source ( CXOU J182913.1-125113 ) and an associated diffuse nebula in the composite supernova remnant G18.95-1.1 .
These objects appear to be the long-sought pulsar and its wind nebula .
The X-ray spectrum of the point source is best described by an absorbed powerlaw model with \Gamma = 1.6 and an N _ { H } of \sim 1 \times 10 ^ { 22 } cm ^ { -2 } .
This model predicts a relatively low unabsorbed X-ray luminosity of about L _ { X } ( 0.5 - 8.0 { keV } ) \simeq 4.1 \times 10 ^ { 31 } D _ { 2 } ^ { 2 } erg s ^ { -1 } , where D _ { 2 } is the distance in units of 2kpc .
The best-fitted model of the diffuse nebula is a combination of thermal ( kT = 0.48 keV ) and non-thermal ( 1.4 \leq \Gamma \leq 1.9 ) emission .
The unabsorbed X-ray luminosity of L _ { X } \simeq 5.4 \times 10 ^ { 33 } D _ { 2 } ^ { 2 } erg s ^ { -1 } in the 0.5 – 8keV energy band seems to be largely dominated by the thermal component from the SNR , providing 87 % of L _ { X } in this band .
No radio or X-ray pulsations have been reported for CXOU J182913.1-125113 .
If we assume an age of \sim 5300 yr for G18.95-1.1 and use the X-ray luminosity for the pulsar and the wind nebula together with the relationship between spin-down luminosity ( via magnetic dipole radiation ) and period , we estimate the pulsar ’ s period to be P \simeq 0.4 s. Compared to other rotation-powered pulsars , a magnetic field of 2.2 \times 10 ^ { 13 } G is implied by its location in the P – \dot { P } diagram , a value which is close to that of the quantum critical field .