Throughout this Primer, data from the HEASARC archive are used to illustrate how
to run tasks for each instrument on XMM-Newton; new users are encouraged to use
these sample data, though in should be noted that any data from the relevant
instrument will do. Information about the example datasets are in Table 5.1.
|Instrument||Chapter (Command line, SAS GUI)||ObsID||Object|
|EPIC (Imaging mode)||6, 7||0123700101||Lockman Hole|
|EPIC-PN (Timing mode)||8, 9||0400550201||Cen X-3|
|RGS||10, 11||0153950701||Mkn 421|
|OM (Image mode)||12.2||0123700101||Lockman Hole|
|OM (Fast mode)||12.3||0411081601||Mkn 421|
|OM (Grism mode)||12.4||0125320801||BPM 16274|
A number of SAS tasks, including those which rerun the pipeline, require an
up-to-date list of calibration files (the CIF file) and extended Observation
Data File (ODF) summary file. These are obtained by running the tasks
cifbuild and odfingest, respectively. Because of these
dependencies, it is strongly recommended that users run these tasks,
whether they plan to rerun the pipeline or not. Since these tasks are very
straightforward to run, we will just call them from the command line and save
the SAS GUI for more interesting tasks.
First, gunzip the all gzipped files in the ODF directory. If necessary,
rename all files in the ODF directory to upper case. This can be done
using the script provided by the NASA/GSFC XMM-Newton GOF.
Many SAS tasks require calibration information from the Calibration Access Layer (CAL). Relevant files are accessed from the set of Current Calibration File (CCF) data using a CCF Index File (CIF). A CIF is included in the pipeline products (*CALIND*), but if the CCF has been updated it can be recreated by the user by simply typing
The task cifdiff can be used to compare the new CIF with the old:
If the CAL has changed, it is a good idea to repipeline the data using the new CIF. To help determine whether it is reasonable to repipeline the data, the CCF release notes should be examined (see §2.5). CCF files can be downloaded directly from the SOC website see (see §4.2).
To use the updated CIF file in further processing, you will need to reset the environment variable SAS_CCF:
The task odfingest extends the Observation Data File (ODF) summary file with data extracted from the instrument housekeeping data files and the calibration database. It is only necessary to run it once on any dataset, and will cause problems if it is run a second time. If for some reason odfingest must be rerun, you must first delete the earlier file it produced. This file largely follows the naming convention described in §3.3.3, but has SUM.SAS appended to it. After running odfingest, you will need to reset the environment variable SAS_ODF to its output file. To run odfingest and reset the environment variable, simply type:
The user will likely find it useful to alias these environment variable resets
in their login shell (.cshrc, .bashrc, etc.).
The rest of this guide consists of step-by-step examples of how to reprocess and analyze data for the EPIC, RGS, and OM; the chapters for each instrument, and which way that SAS is used (on the command line or through a graphical user interface) are listed in Table 5.1. At the start of each chapter, it is assumed that the user has downloaded the data, initialized SAS, and set the environment variables, as listed in 4.3. It is also assumed that the CIF file is up-to-date, the *SUM.SAS file exists, and the appropriate environment variables were reset as needed.
Many first time users will probably find the GUI more useful than the command line. To invoke it, simply type
A window will appear with two panels. The upper one will contain task names, what
group they belong to (such as utility, epic, timing, calibration, etc.) and a short
description of each. The lower one will contain information about environment variables,
and as tasks are invoked, feedback from the tasks. The interface is shown in Fig. 5.1.
Remember that tasks place output files in whatever directory you happened to be
in when the SAS GUI was called, so either open and close the GUI in the directory
where you want the output or move the files to the directory they should be in.