Can I simulate arbitrary combinations of ACIS CCDs in marx?
The simple answer is “no”. Out of the box, marx allows users to select either the ACIS-S array (6 CCDs) or the ACIS-I array (4 CCDs). Arbitrary mixtures of chips from the two arrays are not currently supported although we plan to add that option in a future version of marx. In the meantime, if you do need to simulate other combinations, one can assemble such composites by creating the desired ACIS-S and ACIS-I chips separately and them merging the resulting event lists with the dmmerge tool in CIAO. For such mergers, both pieces of the simulation must have the same aimpoint position.