An X-ray Search for Compact Central Sources in Supernova Remnants I: SNRs G093.3+6.9, G315.4-2.3, G084.2+0.8, & G127.1+0.5

Less than half of the SNRs within 5 kpc have identified central sources, and only three are identified as the remnants of Type Ia SNe. Here, we report a systematic effort to search for compact central sources in the remaining 23 SNRs of this distance limited sample. In this first paper we report Chandra observations of four SNRs. We have undertaken a systematic optical/IR identification program of the X-ray sources detected in the field of each SNR. Foreground and background sources have identifiable IR/optical counterparts, while the counterparts of neutron stars (or black holes) are expected to be very faint. We are able to account for all the well-detected X-ray sources and thus able to state with some confidence that there are no associated central sources down to a level of one tenth of that of the Cas A central source, L_X
52 pages, 37 figures. Accepted for publication by ApJS. Uses emulateapj5.sty, onecolfloat5.sty