15 Advanced: Simulating Observations

Simulations may be need to evaluate whether observations with a given array are relevant or not for the expected science goal. There are 3 basic questions in this respect:

1. What array configuration gives the appropriate beam size.
2. Is the image reconstruction appropriate ?
3. What sensitivity is obtained ?

Case (1) is described in Section 15.1. Case (2) requires a complete simulator as in Section 15.2. The available tools are grouped in the SIMULATE\ language, but are also packages in a all-in-one command named SIMULATE in the IMAGER\ language.

Case (3) is not treated separately by IMAGER, because Observatories like ALMA and NOEMA provide their own tools to figure out the expected noise level. In Case (1), an approximate noise level can be derived using the /WEIGHT FULL option, but it is based on a generic estimate for the system temperature. A user specified noise level (e.g. the one indicated by the Observatory tool) can be accounted for in Case (2).