NAME gteffbkg - Creates maps of the effective background for a point source as a function of position and energy USAGE gteffbkg cmap outfile irfs expcube bexpmap efact DESCRIPTION This tool is used to estimate the effective background that is present for a point source as a function of position and energy. This estimate is defined so that the square root of the effective background is very close to the expected contribution to the uncertainty on a likelihood fit for a point source coming from statistical uncertainty of the background model. It can also be used estimate the effect of systematic uncertainties of the background model, when they can be parametrized as a fraction of the effective background. PARAMETERS cmap [filename] FITS file containing a counts cube representation of the background model we want to compute the effective background for. outfile [filename] Name of the output FITS file that will contain the generated effective background map. irfs [string] Instrument response functions. The instrument response (PSF, effective area, energy resolution) is currently a function of energy, inclination angle (the angle between the source and the LAT normal) and photon category. Since the LAT will usually survey the sky, a source will be observed at different inclination angles. Each count will therefore be characterized by a different instrument response function (IRF). The default value is “CALDB”. evtype [integer] The evtype to be used in generating the background data. The default is INDEF which will use the default in the input file. This can be overridden by entering the desired event type e.g. 3 for FRONT + BACK events. expcube [filename] FITS file containing livetime as a function of sky position and off-axis angle. This file can be generated by gtltcube or obtained from the FSSC website. See the gtltcube help for further explanation. bexpmap [filename] Binned exposure map for on-the-fly source map calculations. If the existing file is specified, that file will be used as the exposure map. Otherwise, a map with that name will be computed based on the energy bands in the srcmaps file. If "none" is given (default value), the map will be called "binned_exposure.fits". efact [float] Energy integration factor. For any particular energy E we integrate the background from E/efact to E when we compute the effective background. (edisp_bins) [integer] Number of extra bins to compute for energy dispersion purposes. This needed to initialize the code, but is not actually used in the computation of the effective background. (chatter) [integer] This parameter fixes the output verbosity: no screen output (0), nominal screen output (2), maximum verbosity (4). Default is "2". (clobber) [boolean] If true, an existing file of the same name will be overwritten. Default is "yes". (debug) [boolean] Activate debugging mode. Default is "no". When debug is "no", all exceptions that are not caught and handled by individual tool-specific code are caught by a top-level exception handler that displays information about the exception and then exits. When debug is "yes", such exceptions are not caught by the top level code. Instead the tool produces a segmentation violation, which is more useful for debugging. When debugging mode is enabled, the tool produces more verbose output describing any errors or exceptions that are encountered. (gui) [boolean] Graphical User Interface (GUI) mode is activated if set to "yes". Default is "no". (mode) [string] Mode of automatic parameters: "h" for batch, "ql" for interactive. Default is "ql". EXAMPLES Parameters are passed following the FTOOLs model: They could be passed answering from a prompt, as a list in a command line, or by editing the parameter file. To run gteffbkg simply type in the command line: > gteffbkg The parameter values have to be provided. Not all parameter are prompted: some of them are "hidden". To change one of the "hidden" parameter, the user should specify the values in the command line or modify its mode by editing the parameter file. For example, to avoid overwriting the outfile, the following command line has to be typed: > gteffbkg clobber=no An example of how to run the tool is given below: > gteffbkg Input counts, source or model map file[] cmap.fits Output File[] effbkg.fits Response functions[CALDB] Exposure cube[] expCube.fits Binned exposure map[] bexposure.fits Energy integration factor[2] That last example could be also run in the command line as follows: > gteffbkg cmap=cmap.fits outfile=effbkg.fits irfs=CALDB expcube=expCube.fits bexpmap=bexposure.fits efact=2. SEE ALSO gtlike gtsrcmaps gtltcube gtalphbkg gtwtsmap