Effective areas for WCD and neutrino instruments #14
Description
The provision of effective areas might be associated to a data release, and as a consequence should be used differently by the science analysis tools.
We have indeed several cases:
- a data release might be intended to stack data over more than one year. In this case, the effective area can be provided in units of [cm2 transit-1] per RA band. In this regard, this is not really an effective area, neither an exposure map.
- Then, the science tool can compute the number of transits for N years of a given source and derive the exposure map.
- for shorter exposure analysis, the number of transit will not be an integer. For very short exposure, the source transits only in a couple of altitude band; for a several month exposure, one will have N transits plus a fraction of transit. In this case, a fine computation will be the provision by the data producer of the effective area in [cm2] as function of the elevation.
- Then, the science tool should compute the time spent in each elevation band of each transit of the source for the user analysis time interval in order to derive the exposure map
As seen here, one should define with accuracy the different types of "effective area" that VODF could face on, their units and their dependency. And dedicated EXTNAME and/or metadata might be needed when deviating from a pure effective area.
This issue aims to list the different quantities and to describe them in detail, in order to define EXTNAME and metadata.
Questions:
- Is there other science case?