The AO-21 open time deadline was on 29 September 2023. The total number of proposals received was 61, and the total observing time requested is about 87.1 Msec. Assuming up to about 21 Msec of observing time for new observing proposals will be available for the AO-21 observing programme, this corresponds to an oversubscription in time by a factor of 4.1. The non-ToO proposals requested data rights for 354 sources in total.
In the table below we give the breakdown of number of proposals as a function of the proposal category. Note that the numbers of requested observing time include ToO proposals, and it was assumed that the typical ToO trigger probability is about 10%. The respective requested exposure time has been reduced accordingly.
Out of the 61 received proposals, 11 requested a total of 645ks from the joint programme with XMM-Newton, NuSTAR or Swift (5+4+2 with 390ks, 195ks, and 60ks, respectively). In addition, various campaigns coordinated with other high-energy and radio observatories were requested.