All Herschel telemetry and auxiliary data will be automatically processed at the HSC with the Standard Product Generation software (SPG), to produce the observational data products. The following four levels of Herschel data products are defined:
Level-0 data product: Raw telemetry data as measured by the instrument, minimally manipulated and ingested as Data Frames into the mission data base/archive.
Level-1 data product: Detector readouts calibrated and converted to physical units, in principle instrument and observatory independent. It is expected that level-1 data processing can be performed without human intervention.
Level- 2 data product: Level-1 data further processed to such a level that scientific analysis can be performed. For optimal results many of the processing steps involved to generate level-2 data may require human interaction, based both on instrument understanding as well as understanding of the scientific aims of the observation. These data products are at a publishable quality level and should be suitable for Virtual Observatory access.
Level-3 data product: These are the publishable science products where level-2 data products are used as input. These products are not only from the specific instrument, but are usually combined with theoretical models, other observations, laboratory data, catalogues, etc. Their formats should be Virtual Observatory compatible and these data products should be suitable for Virtual Observatory access.
While the generation of level-0 and level-1 data products will be automatic, proper quality level-2 and level-3 data products may require interactive processing. It is expected that the degree of human intervention necessary to generate these products will decrease with time as the knowledge of the instruments' behaviour increases during the mission. This is the same as saying that the quality of the automatically generated product will be progressively enhanced. However, in many cases it will not be possible to discard interactive processing, especially in the derivation of level-3 data products.
In addition to these observational products, calibration, auxiliary and quality control products will be provided. For more information on the Herschel products, please see the corresponding Instrument Observer Users' Manual. The Herschel Products Definitions document and the Herschel Data Users' Manual document contain detailed descriptions of all Herschel data.
Herschel data products will be stored in the Herschel Science Archive. By using the Herschel Science Archive Browser, astronomers will be able to search, browse, select and retrieve data products according to the observations proprietary rights. The Herschel Science Archive will also act as a repository of highly processed data products provided by the astronomical community. When requesting observational data from the Herschel Science Archive, the user will be offered as options:
(i) to retrieve directly the stored products,
(ii) to request re-processing with the latest SPG version, and
(iii) to perform On-Demand processing of the selected observations. In the latter, the user customises the standard product generation by choosing values for given parameters that will depend on the type of observation (e.g. low flux observation data processing).
In addition to standard products, a Herschel Observer Interactive Analysis package will be offered to the astronomical community to interactively reduce the Herschel data (starting from level-0, -1 or -2 products), and to perform science analysis. The Herschel Interactive Analysis package does not require commercial licenses and is built to be platform-independent. The distribution will include source of software, calibration data and documentation. In addition, the astronomer will be able to develop and integrate his/her own data processing algorithms within the system.