Examples of Image Creation

Now you can go to the directory created with og_create and start the analysis

cd obs/crab
jemx_science_analysis startLevel="COR" endLevel="IMA" nChanBins=-4 jemxNum=2

The above command launches the analysis which will run from the Correction step (startLevel="COR") up to the image creation level (endLevel="IMA"). It is important to specify that we are interested in the second of JEM-X instruments: jemxNum=2. nChanBins parameter specifies the energy binning (see section 6.7.2 for details).

At the beginning the script launches the GUI (Fig. 10)

Figure 10: GUI for JEM-X science analysis.

and you can check the parameter settings (the full list of the parameters is given in Table 60). Only the most important parameters (shown in bold in Table 60) appear within the main panel of GUI. To access the other ``hidden'' parameters click on the button ``hidden'' on the right side of the panel.

In the upper frame of the front panel called ``General'' you can choose at which level you want to start and stop the script execution. In the Overview chapter you have seen that there are different processing levels of the analysis. You can choose to run only some of them. The default settings of the jemx_science_analysis script are

startLevel="COR"	start the script at COR level,
endLevel="IMA2"	stop the script at IMA2 level.

It is advisable always to start with level COR. This will allow the processing of the data using the latest knowledge of the calibration of the instrument.

If you want to skip some levels, click on the ``hidden'' button on the right of the GUI panel to access the whole set of jemx_science_analysis parameters. In the frame ``General'' you find the skipLevels parameter. However, be always careful while setting this parameter - levels often depend on the previous ones, so make sure that your selection makes sense. Another useful hidden parameter IMA_skyImagesOut in the IMA section enables you to choose the types of images which you want to output.

The source flux is extracted using the IMA step, in order to profit from the vast improvement in the modelling of the JEM-X instruments achieved in OSA 8. With OSA 10.1 the images are extracted by default in the same energy binning specified under "General Binning Tasks". To generate images in arbitrary energy bands, see section 6.6.7. As in the previous OSA versions, the optimal source detection is still obtained through j_ima_iros in 3 default energy ranges: 3-7 keV, 7-11 keV and 11-20 keV. The checkbox IMA_detImagesOut enables you to output also the images in these pre-defined energy bands. This option is not recommended if you want to extract a spectrum from the mosaic image later.

In the middle of the GUI front panel you have a possibility to choose a ``user input catalog'' (the parameter CAT_I_usrCat). At the moment you can leave it empty (the software will use the general INTEGRAL source catalog for the analysis). However, for the correct extraction of spectra and lightcurves of the sources it is recommended to create a ``user catalog'' with the positions of the sources for which you plan to extract the spectra and/or the lightcurves. We will come back to this in the following sections (and sect. 7.5).

Once you are satisfied with the settings, save them by pressing the ``Save As'' button at the front panel of GUI and then press ``Run'' to start the data reduction.