High Velocity Gas in the Line of Sight to the Vela SNR

One of the best objects for study of the structure, kinematics, and evolutionary status of a middle-aged supernova remnant (SNR) is the VELA SNR, due to its proximity, extensive optical filamentary structure, and an abundance of hot background stars for absorption line research. The VELA remnant is 7.3 degrees in diameter, based on x-ray imagery with ROSAT, with the pulsar nearly centered in the remnant. The western region of the remnant has much lower x-ray surface brightness than the remainder of the remnant and in fact escaped earlier detection with previous instrumentation. The remnant is believed to be about 11,000 years old.