On November 9, about 2/3 of imaging area of XIS2, one of the X-ray CCD cameras, became suddenly unusable. All other sensors, XIS0, 1, 3, are fine. Since there was a concern that the start of spaced-row charge injection (SCI) might have triggered the problem, we temporally stopped the SCI just after the trouble. However, after extensive analysis and in-orbit and ground tests, we concluded the SCI is not related to the trouble. We will soon resume the SCI step by step.

Our attempts to recover XIS2 have so far proven unsuccessful, but we will continue our efforts to identify the cause of the problem. In the mean time, we will increase the exposure times of Priority A targets of cycle-1 GO observations by 25 %, and use them as the observation-completion criteria. However we will not increase those of Priority B and C targets, thus the observation-completion criteria for Priorities B and C remain the same.

We ask cycle-2 proposers to perform proposal simulations assuming four XIS sensors. We will consider adjusting observation times according to evaluation by the selection boards.

best regards,