A galactic supernova remnant ( SNR ) Vela Jr. ( RX J0852.0 - 4622 , G266.6 - 1.2 ) shows sharp filamentary structure on the north-western edge of the remnant in the hard X-ray band .
The filaments are so smooth and located on the most outer side of the remnant .
We measured the averaged scale width of the filaments ( w _ { u } and w _ { d } ) with excellent spatial resolution of Chandra , which are in the order of the size of the point spread function of Chandra on the upstream side and 49.5 ( 36.0–88.8 ) arcsec on the downstream side , respectively .
The spectra of the filaments are very hard and have no line-like structure , and were well reproduced with an absorbed power-law model with \Gamma = 2.67 ( 2.55–2.77 ) , or a SRCUT model with \nu _ { rolloff } = 4.3 ( 3.4–5.3 ) \times 10 ^ { 16 } Hz under the assumption of p = 0.3 .
These results imply that the hard X-rays are synchrotron radiation emitted by accelerated electrons , as mentioned previously .
Using a correlation between a function { \cal B } \equiv \nu _ { rolloff } / w _ { d } ^ { 2 } and the SNR age , we estimated the distance and the age of Vela Jr. : the estimated distance and age are 0.33 ( 0.26–0.50 ) kpc and 660 ( 420–1400 ) years , respectively .
These results are consistent with previous reports , implying that { \cal B } –age relation may be a useful tool to estimate the distance and the age of synchrotron X-ray emitting SNRs .