iThe SRCTYPE keyword is used only for spectroscopic observations and gives the pipeline.s best guess as to whether the source is point, extended, or of an unknown type. This information can come from several different places upstream in the pipeline or the ground system. For spectroscopic observation modes that involve a single source, such as MIRI LRS, MIRI MRS, NIRSpec fixed-slit, NIRSpec IFU, and NIRISS SOSS, the user can enter the source type in the APT template for the observation. That choice gets passed along to DMS level-1 processing via the PPSDB and results in this keyword getting populated. For NIRSpec MSA observations, the user can enter this information for each source used in the MSA Planning Tool (MPT) in APT. These selections get stored in the PPSDB nirspec_sources table, which get copied to the MSA meta data file created by DMS and subsequently used as input to the level-2b calibration pipeline. The calibration pipeline copies the values from the MSA meta data file into the SRCTYPE keyword associated with each extracted MSA slitlet. In the event the user does not make a source type selection during APT processing for either of these two cases, the calibration pipeline will make default choices based on the observing mode. Finally, for the case of NIRCam and NIRISS Wide-Field Slitless Spectroscopy (WFSS) observations, source extents are determined by the calibration pipeline during level-2b processing of the direct images associated with a WFSS observation and stored in the resulting source catalog. During level-2b processing of the spectroscopic WFSS exposures, the information from the source catalog is used to populate the SRCTYPE keyword for each extracted source.
| Attribute | Value |
|---|---|
| data type | string |
| enumerated Values | not defined |
| units | |
| example | |
| default value | unknown |
| special processing | not defined |
| source | Calibration Software |
| software source | |
| calculation | |
| DB destination | ['ScienceSlit.srctype'] |
| data type in DB | nvarchar(15) |
| instrument | NIRCAM,NIRISS,NIRSPEC |
| mode | NRS_MSASPEC, NRS_FIXEDSLIT, NIS_WFSS, NRC_GRISM |
| product level | 2b |
| FITS hdu | SCI |
| FITS header section | Slit parameters |