Summary release note for ppsprod-21.80
======================================

Pipeline Version: 21.80_20260604_1143
Pipeline name: ppsprod
Release Date: 2026-06-04
SAS build identifier: xmmsas_22.1.0-5ba234281-20250924
SAS branch-commit: pps-sas21.0.0-5ba234281



Summary
=======
This pipeline is based in SAS21 where some extra corrections in the
effective areas of EPIC and RGS instruments are now applied by default.
The correction for the time degradation of the OM sensitivity has also 
changed with special treatment of sources near the boresight.

A major change in the source detection algortithm for EPIC cameras 
has been implemented to improve the significance of the detections
specially the weaker ones.

A brief description of the most relevant changes is provided below. 
For more detailed description reader is referred to the release notes 
of SAS21 and relevant CCFs and the Pipeline Products Description document 
available in XMM-Newton  SOC web pages 
(https://www.cosmos.esa.int/web/xmm-newton)

-) The new source detection method assumes a constant flux across different
EPIC exposures for each candidate source in each energy band. It also 
assumes the spectra of all sources can be described by a powerlaw 
with the same spectral index and absorbing HI column density for all EPIC
exposures and energy bands though different from source to source. Then, 
the free parameters of the fitting process for each source are the location 
of the source, the model parameters that best represent the relative 
rates in the five energy bands in all EPIC cameras and the flux of the source
during the obervation. As the new approach reduces noticeably the number of 
free parameters the significance of the detections increases, specially for 
weak sources. Once the positions are determined for the final source list,
the rate in each band and exposure is computed in a second step as PSF 
photometry.

-) Although the flux of the source during the observation is one of the 
fitted parameters by the detection algortihm, the conversion from rates to 
fluxes in the different bands and cameras is still based on a model with 
spectral index 1.7 and absorbing HI column density 3E20cm-2. 
The Energy Conversion  Factors are computed with the extra corrections 
mentioned above below, including the time dependency of the contamination in 
the MOS cameras.

-) MOS effective areas incude a correction for flux agreement with EPIC-pn

-) pn effective areas include a correction for spectral agreement with NuSTAR

-) RGS effective areas include rectification factors for flux agreement with EPIC-pn

-) OM mosaic images are now created per filter and observation, merging all exposures
from the same filter independently of the mode. Source detection on mosaiced images
are performed only if more than one exposure contributes to the mosaic. Further, 
sources detected in mosaiced images are discarded if they are located in a pixel
where only one exposure contributes.

-) A new method to correct for the OM sensitivity degration with time has been
implemented, with a spectial treatment of sources near the boresight.

The version of SAS being used is a pipeline-specific branch pps-sas21.0.0
at commit level 5ba234281. This is based on the public SAS release 21.0.0,
described at
http://www.cosmos.esa.int/web/xmm-newton/sas-release-notes-2100



Documentation
=============

Documentation for this pipeline can be found at:

http://www.cosmos.esa.int/web/xmm-newton/pipeline

and links therein.