Overview of LAM 1D Data Products
What is the LAM 1D DRP?
This section summarises the data products produced by the LAM 1D pipeline. The pipeline operates downstream of the PFS 2D DRP and takes the pfsCoadd spectra as input to perform:
- Redshift determination — fitting galaxy, QSO, and stellar templates to estimate redshifts or radial velocities
- Object classification — classifying each spectrum as
GALAXY,QSO, orSTARwith associated probabilities - Emission and absorption line measurements — measuring line fluxes, widths, equivalent widths, and velocities
- Quality assessment — flagging spectra with warnings and errors at each stage of the pipeline
The core fitting engine is the drp_1d library (also known as pylibamazed), developed and maintained by LAM.
Input and Output
The LAM 1D DRP takes the fully reduced and coadded spectra from the 2D DRP and produces redshift candidate collections:
| Input | Description |
|---|---|
pfsCoadd |
Coadded, flux-calibrated spectra across multiple visits |
| Output | Description |
|---|---|
pfsCoZCandidates |
Coadded redshift candidates collection, following pfsCoadd logic — one file per catId |
pfsCoZCandidates is the output for science analysis. It bundles results for all objects in a catalog into a single file per catId+objGroup containing redshift candidates, classification probabilities, PDF grids, line measurements, and quality flags for each object.
Version Keywords
The PDU of every pfsCoZCandidates file records the software versions used to produce it:
| Keyword | Description |
|---|---|
D1D_VER |
Version of the drp_1d library |
D1DP_VER |
Version of the drp_1dpipe pipeline |
DAMD_VER |
Version of the PFS data model |
D2D_VER |
Version of stella (2D DRP) |
OBS_VER |
Version of obs_pfs |
U_PARAM |
User parameters (JSON string) |