Searching First Robust Evidence of Charge Exchange Emission from the Cygnus Loop

We propose to observe a southwestern knot (SWK) in the Cygnus Loop. The aim isto find first robust evidence for charge exchange (CX) emission from SNRs. Ourcomprehensive SUzaku XIS studies have found a possible sign of CX. However, dueto the lack of the energy resolution of the XIS, we cannot resolve them clearlyand thus cannot exclude other possibilities from their spectra. The SWK is oneof the brightest and the most compact region among them. Our simulation showsthat the RGS can clearly divide the O Hea and the Ne Hea triplets into threelines. Their forbiddentoresonance ratios are useful to find conclusiveevidence for the existence of CX emission from the Cygnus Loop. A 100 ksobservation is required for this purpose. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]