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XRISM data analysis requires multiple software packages, which are available for free. This chapter presents the software and the tools to analyze the XRISM data.
XRISM users can reduce the data using the HEASoft package developed by the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA's GSFC.
https://heasarc.gsfc.nasa.gov/docs/software/lheasoft/
HEASoft is a unified release of the FTOOLS software package, a collection of programs and scripts with command-line interface for NASA's space science mission data and their reductions, and the XANADU package for image, light curve, and spectral analysis. The XRISM instrument teams provide all mission-specific tools to recalibrate and analyze XRISM data beginning with version 6.34, which are collectively called the “XRISM FTOOLS”. XRISM users must use XRISM FTOOLS to recalibrate XRISM data and produce their image, light curve, and spectrum products. Users can continue in-depth analyses of those products using ximage, xronos, and xspec of the XANADU package. Since the science products are OGIP compliant FITS files, users may utilize software outside of the HEASoft suite (e.g., CIAO). However, XRISM Guest Observer Facility (GOF) may not support the use of other tools.
HEASoft runs on major Unix architectures, Linux and OS X. HEAsoft should run on Cygwin on Windows in principle, but caveats may arise (see HEASoft website). XRISM users are strongly encouraged to use one of the supported Unix systems, listed on the HEASoft website. The HEASoft package is nominally released approximately once a year, but patches of the XRISM FTOOLS may be released on a faster timescale as needed. Please check the XRISM web page frequently for information. Users may also like to subscribe to the mailing list for announcements relevant to the XRISM community of general observers, by sending an email to xrism-announcements-join@lists.nasa.gov with `subscribe' in the subject line.
The FTOOLS fhelp command is arguably the most important but underrated tool in HEASoft. Users can look up the detailed usage and the option description of any HEASoft tools. After setting up the HEASoft environment, type
term> fhelp `command'
to find the command description. Users can also list all HEASoft tools by typing
term> fhelp ftools
We recommend that users check fhelp to avoid or solve software-related problems. Users can also find the online version on the HEASoft web page.
The FTOOLS fv command is a handy tool for viewing images or tables inside a FITS file. It also has functions to make plots or basic statistical analyses, which are convenient for checking HK or observational data. To launch fv, type
term> fv FITS_file_name
or simply
term> fv
and locate the file using `fv: File Dialog'.
The FTOOLS punlearn command resets the parameters of the specified command to their default values, so parameters that are not specified in a command are not set to previously used values. To reset the parameters of a command, type
term> punlearn `command'
Xselect is a multi-mission command-line interface in the HEASoft suite, which loads X-ray event data, selects events with various user-defined conditions such as sky areas, time intervals, and photon energies, and outputs image, light curve, and spectral FITS products after filtering data. It works interactively, preserving all filtering conditions and organizing information during a run. Thus, users can focus on data analysis without having to manage tedious command options for running the FTOOLS extractor event extraction tool, which does the job behind Xselect. It has been widely used to analyze X-ray event data from ASCA, ROSAT, BeppoSAX, Einstein, Suzaku, and other high-energy missions. XRISM GOF recommends that users use Xselect to manipulate XRISM event data. Users unfamiliar with Xselect should read the following online manual.
https://heasarc.gsfc.nasa.gov/docs/software/lheasoft/ftools/xselect/xselect.html
Heasoftpy supports a Python 3 interface to the HEASoft tools, allowing users to integrate the HEASoft package into their Python codes or other Python libraries publicly available. The details can be found at:
https://heasarc.gsfc.nasa.gov/lheasoft/heasoftpy/
XRISM FTOOLS access the observatory's calibration information through Calibration Database or CALDB:
https://heasarc.gsfc.nasa.gov/docs/xrism/calib/index.html
XRISM users may install the whole set of XRISM CALDB from HEASARC or access the remote database at NASA/GSFC at each run. The database stores all calibration versions from the mission start, and users can access any of them if needed. However, most users need only the latest CALDB information, so CALDB has a device that provides a file with the newest calibration information for each calibration category. Hence, users only need to specify “CALDB” with appropriate command options or don't even need to select them as they are hidden and their default values are “CALDB”. The tools automatically pick the newest calibration files.
The following URL explains the procedures for installing the CALDB database on a local disk or setting up the remote access.
https://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/caldb_intro.html
The local CALDB installation enables faster access to the calibration data, which may be especially important for users with limited internet connection. The remote CALDB access ensures that users utilize the most up-to-date calibration without monitoring the CALDB update and updating the CALDB data. Users can obtain the XRISM CALDB version information from the above web page.
SAOImage is an astronomical imaging and data visualization application developed by the Harvard & Smithsonian Center for Astrophysics. It is outside the HEASoft suite but is a default image viewer of Xselect. Users can download the application from the following URL.
https://lweb.cfa.harvard.edu/resources/software.html
XSLIDE (X-ray Spectral Line Identification Energy) is a spectral analysis software package that the XRISM Science Data Center plans to release. XSLIDE uses a graphical user interface to assist users in XRISM spectral analysis, allowing for line identification and basic plasma diagnostics using information stored in external files. It is a powerful line diagnostics tool that particularly helps understand the Resolve data. However, it does not make spectral fittings, so it is suitable for supporting detailed spectral analysis with xspec. We will announce the release on the XRISM web page.
Sciserver is a cloud computing service maintained by HEASARC that allows users to analyze space science data in the HEASARC archive with a remote computer. HEASARC promptly updates the HEASoft, CALDB, and archival data in Sciserver, so users only need to access the server to analyze data. Anyone can create an account for free and is allotted 10GB of disk space. For the details, please see the following URL.