The Evolved Yet Oxygen-Rich SNR CTB 1:SN Ejecta Clumping and Hard X-ray Emission

Based on prior ROSAT observations, the supernova remnant (SNR) CTB 1 featuresXray centerfilled emission within a welldefined radio shell, characteristicof mixedmorphology SNRs. Our ASCA and Chandra observations revealed that CTB1 is an oxygenrich SNR with enhanced abundances of O and Ne despite its evolvedstate. We also found a hard component to the Xray emission, and our Chandraimages suggest that the hard emission may be localized. Our scientific goals arei) to examine clumping structures of SN ejecta, where the ejecta are stilldominant at an old age, ii) to determine if the hard emission has a nonthermalorigin and is truly localized, and iii) to resolve the hard pointlike sourceand determine if it is a pulsarwind nebula associated with CTB 1. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]