Release 27.0.0 (2024-06-25)

Source	Identifier
Git tag	27.0.0
EUPS distrib	v27_0_0
rubin-env version	8.0.0

This release is based on the w_2024_16 weekly build with 3 tickets backported.

The notes below highlight significant technical changes to the Science Pipelines codebase in this release. For a complete list of changes made, see Tickets Addressed in Release 27.0.0.

The Characterization Metric Report (DMTR-431) describes the scientific performance of this release in terms of scientific performance metrics.

If you have questions or comments about this release, visit our Community forum for advice.

• Major new features

• Significant interface changes

• Deprecations

See also:

• Installation instructions

• Known issues

• Doxygen Documentation

Major new features

• Cell Coadds Package

• Source Injection

• Ingestion of Fiber Spectrograph Data

• Support for Generic Cameras

Cell Coadds Package

The cell_coadds package includes data structures for defining coadds of astronomical images in small (few arcsecond) cells, in which only input images that fully contain a cell are included. This helps mitigate problems with PSF discontinuities that are present in traditional coadds.

Pipeline tasks that use these data structures to actually build cell-based coadds are in development as of this release and maybe be usable, but they are not stable and are not included in the main DRP pipelines.

Ingestion of Fiber Spectrograph Data

The obs_fiberspectrograph package adds support for data from fiber spectrographs that Rubin Observatory uses to monitor calibration light sources.

Support for Generic Cameras

The obs_rubinGenericCamera package adds support for data from the generic cameras used at Rubin Observatory, including the star trackers, the AuxTel pointing camera, and the all-sky camera.

Source Injection

The source injection package (GitHub) contains tools designed to assist in the injection of synthetic sources into scientific imaging at various points in the Rubin pipelines. Source generation and subsequent source injection is powered by the GalSim software package.

Significant interface changes

New packages added

• cell_coadds (see above)

• obs_fiberspectrograph (see above)

• obs_rubinGenericCamera, (see above)

• source_injection (see above)

• scarlet_lite, an optimized subset of the original Scarlet package used and maintained by Rubin DM.

Packages removed

• scarlet_extensions, obsolete scarlet utilities.

Task and Data Product changes

• The Alert Production pipelines now use the new CalibrationImageTask for PSF modeling, background, subtraction, and initiall calibration immediately after ISR, instead of the two-task sequence of CharacterizeImageTask and CalibrateTask. The new task is leaner and simpler, and it can handle pairs of “snaps”, but its output data products are slightly different. It will be included in the Data Release Production pipelines in a future release.

Deprecations

These tasks or methods are now deprecated and will be removed in the next major release. See RFC-945 for a clarification on the accelerated deprecation policy.

• Deprecations in lsst.pipe.tasks

• Deprecations in lsst.meas.base

• Deprecated task configurations

Deprecations in lsst.pipe.tasks

The python classes SetPrimaryFlagsConfig and SetPrimaryFlagsConfig have been moved to lsst.meas.algorithms.

The coaddition tasks AssembleCoaddTask and CompareWarpAssembleCoaddTask have moved to lsst.drp.tasks.

Deprecations in lsst.meas.base

The plugin NaiveCentroid is deprecated.

Deprecated task configurations

In FgcmFitCycleConfig the configuration field nCore will be removed. Please specify the number of cores with pipetask run --cores-per-quantum instead.

In CatalogMatchConfig targetDecColumn has been been replaced by targetRaColumn and decColumn has been replaced by targetDecColumn.