ALEXIS Observations of the Monogem Ring Supernova Remnant

The subject grant is for the analysis of ALEXIS observations of the Monogem Ring supernova remnant using the diffuse all-sky maps produced from the ALEXIS all-sky survey. The work is to produce ratio maps of the three energy bands provided by ALEXIS, analyze the ratio data to constrain the intervening neutral hydrogen column density and the temperature and elemental abundances of the X-ray emitting gas, compare the structure to that observed in the ROSAT maps, and incorporate the results into current supenova remnant evolution models. The work outlined above has been significantly delayed since the ALEXIS diffuse all-sky maps took longer to produce than anticipated. Unfortunately, the ALEXIS satellite suffered a failure of the Pegasus launch vehicle which left the satellite in a partially functioning condition. The attitude control system of the spacecraft was unable to operate as planned and this has greatly increased the complexity of the aspect solution. Our colleagues at Los Alamos have made progress in producing these maps and are nearing completion of the final maps. However, the quality of the data have been significantly compromised by the overall lower exposure due to the spacecraft problems and the higher background of the micro-channel plate detectors. We have compared the ALEXIS and ROSAT maps of this region of the sky and there is no obvious signal in the ALEXIS maps of the Monogem Ring. We are now exploring correlation techniques to determine if there is indeed a faint signal in the ALEXIS maps. Although, the project has been a disappointment so far, the data may still provide a valuable lower limit on the neutral hydrogen column density. This is a far cry from our original intentions, but would still be valuable science. Given the large delays in producing the ALEXIS sky maps, this work will continue past the end of the grant period.