2. Software

Suzaku data reduction is primarily performed using the HEAsoft package, which is described in detail at: http://heasarc.gsfc.nasa.gov/docs/software/lheasoft/.
HEAsoft is a multimission collection of programs and scripts (frequently also called FTOOLS, for historical reasons), all using a similar interface which can be used both interactively and in scripts. All mission-specific software required to calibrate and analyze Suzaku data are written by the instrument teams and released as a part of HEAsoft and are collectively called the ``Suzaku FTOOLS.'' By using Suzaku FTOOLS, Suzaku users can recalibrate their data when new calibration information is made available. HEAsoft is supported on major Unix architectures, such as Linux, Solaris and OS X. HEAsoft runs on Windows in principle, but not yet as smoothly as on Unix. Therefore, Suzaku users are strongly suggested to use one of the supported Unix systems, listed on the HEAsoft website.

Major releases of the entire HEAsoft package is currently scheduled approximately once a year. At this stage of the mission, Suzaku FTOOLS will evolve on a faster timescale, and will be released as patch releases as often as once every three months. This guide assumes that the users have installed Suzaku FTOOLS version 5 in HEAsoft version 6.3 or later, since this is required to analyze Version 2 processed Suzaku data. The most recent release (HEAsoft version 6.4) includes Suzaku FTOOLS version 7. An up-to-date and complete listing of Suzaku FTOOLS can be found at:
http://suzaku.gsfc.nasa.gov/docs/suzaku/analysis/suzaku_ftools.html.

Since Suzaku data files are in FITS format, other analysis suites (such as CIAO) can be used with Suzaku files to complete certain tasks. However, due to limited resources the Suzaku GOF will focus support on using HEAsoft to analyze Suzaku data and only support other tools as time permits.

2.1 CALDB

Suzaku calibration information is provided to the users via the HEASARC ``Calibration Database'' (CALDB):
http://suzaku.gsfc.nasa.gov/docs/heasarc/caldb/caldb_intro.html. Many Suzaku FTOOLS cannot run if they cannot access CALDB files. While it is possible to run the tools by specifying the paths to individual CALDB files, this is not recommended since it puts undue burden on the users to know the paths to the correct and up-to-date calibration files for each calibration parameter of each tool. Instead, CALDB provides index files and other infrastructure so that Suzaku FTOOLS can determine the correct file to use, open it and read its contents. The users of such tools need only specify ``CALDB'' (or ``AUTO'' in some cases; these are the default values in the Suzaku FTOOLS distributions) instead of the full path name of calibration files.

As explained at the above URL, CALDB can be installed on the users' local machines or accessed remotely. The latter ensures that the most up-to-date version is used, but there may be a penalty in terms of speed of access. In the former case, it is the local CALDB manager's responsibility to ensure that the latest version is installed. Note that the Suzaku calibration files may be updated as frequently as once a month; the latest version are described at, and can be obtained from
http://suzaku.gsfc.nasa.gov/docs/heasarc/caldb/suzaku/.

To set up access to the local installation of CALDB, source the caldbinit file in the CALDB tree in the directory software/tools (either calidbinit.csh or caldbinit.sh can be used depending on the shell being used; note that these script must be edited to fit the location of the CALDB on each system). This will set up the environment variables that are necessary for the use of CALDB. The remote access method is explained at
http://suzaku.gsfc.nasa.gov/docs/heasarc/caldb/caldb_remote_access.html.

2.2 XSELECT

xselect is a multi-mission program which has been widely used to analyze data from ASCA, ROSAT, BeppoSAX, Einstein, Chandra and other high energy missions. After passing through standard processing, Suzaku event files do not require any particular analysis software, since they comply with FITS event file standards. Nonetheless, the Suzaku GOF recommends xselect as a convenient and straightforward analysis tool. Therefore, in this document it is assumed readers will use xselect to extract Suzaku data into spectra, images, and lightcurves. The primary purpose of xselect is to provide a ``shell'' that translates simple commands (such as ``extract image'') into more complicated mission- or instrument-dependent FTOOLS commands. This guide, however, will not describe all the features of xselect. Users unfamiliar with xselect should read the xselect manual, available at
http://suzaku.gsfc.nasa.gov/docs/software/lheasoft/ftools/xselect/xselect.html. The most important FTOOL used by xselect, extractor, does the actual work of extracting images, spectra, light curves or newly filtered event files from input event files. Users wishing to create scripts based on xselect commands will likely want to use extractor directly.

2.3 XANADU

XANADU is a mission-independent data analysis software package for high energy astrophysics which is normally distributed as part of the HEAsoft package. Currently XANADU includes XSPEC for spectral analysis, XIMAGE for image analysis, and XRONOS for timing analysis. Suzaku spectral, image, and timing analysis may be carried out within XANADU. In particular, the Suzaku GOF will fully support spectral analysis using XSPEC, and provide spectral response files (and/or response generators) with the XSPEC standard format. This guide assumes that the user is generally familiar with the XANADU package but if not, more information can be found at: http://suzaku.gsfc.nasa.gov/docs/xanadu/xanadu.html.

2.4 Profit

Profit is a new spectral analysis tool with a graphical user interface, designed generally for high-resolution spectroscopy but with Suzaku in mind. Profit is in active development and the reader is directed to
http://suzaku.gsfc.nasa.gov/docs/software/profit/ for download instructions and details of its current functionality. In its initial release, Profit can display Suzaku spectra, focusing in and out as desired. Emission lines in the spectrum can be labelled using atomic data from either the ATOMDB or XSTAR line lists. The user can also select individual emission lines and redisplay the data in velocity space to search for line broadening or a Doppler shift. Profit has some ability to fit spectra, although this is rudimentary compared to XSPEC which is recommended when performing measurements for publication. Despite this limitation, Profit may be useful as a ``first-look'' tool when examining Suzaku data, especially for users not familiar with X-ray spectroscopy.