cssens
Computes differential or integrated CTA sensitivity.
Synopsis
This script computes the differential or integrated CTA sensitivity using maximum likelihood fitting of a test source. The differential sensitivity is determined for a number of energy bins, the integral sensitivity is determined for a number of energy thresholds. The test source is fitted to simulated data using :doc:`ctlike` to determine it's detection significance as a function of source flux. The source flux is then varied until the source significance achieves a given level, specified by the (hidden) significance parameter sigma.
The significance is estimated using the Test Statistic value, defined as twice the log-likelihood difference that is obtained when fitting the simulated data with and without the test source. The simplified assumption is made that the significance (in Gaussian sigma) is the square root of the Test Statistic.
:ref:`cssens` will generate an ASCII file in comma-separated value (CSV) format containing the sensitivity as function of energy. The first row is a header row providing the column names. The following rows provide the mean logarithmic energy and the boundaries of the energy bin for which the sensitivity was computed. They also provide the flux within the energy bin in Crab units, in photons (ph/cm2/s) and in energy (erg/cm2/s). Finally, the sensitivity is given as the test source spectrum evaluated at the mean logarithmic energy multiplied by the energy squared (erg/cm2/s).
The sensitivity can be displayed using the show_sensitivity.py script in the example folder. Matplotlib is required to execute the script.
General parameters
- (inobs = NONE) [file]
- Input event list, counts cube or observation definition XML file.
- inmodel [file]
- Input model XML file.
- srcname [string]
- Name of the source in the source model XML file which should be used for sensitivity computation.
- caldb [string]
- Calibration database.
- irf [string]
- Instrumental response function.
- (edisp = no) [boolean]
- Apply energy dispersion to response computation?
- (deadc = 0.98) [real]
- Average deadtime correction factor.
- outfile [file]
- ASCII file containing the sensitivity values.
- (offset = 0.0) [real]
- Offset angle of source in field of view (in degrees).
- duration [real]
- Effective exposure time (in seconds).
- rad [real]
- Radius of Region of Interest (RoI) (in degrees).
- emin [real]
- Lower energy limit for sensitivity computation (in TeV).
- emax [real]
- Upper energy limit for sensitivity computation (in TeV).
- bins [integer]
- Number of energy bins for sensitivity computation.
- (enumbins = 0) [integer]
- Number of energy bins (0=unbinned).
- (npix = 200) [integer]
- Number of pixels for binned analysis.
- (binsz = 0.05) [real]
- Pixel size for binned analysis.
- (type = Differential) <Differential|Integral> [string]
- Sensitivity type.
- (sigma = 5.0) [real]
- Significance threshold.
- (max_iter = 50) [integer]
- Maximum number of iterations.
- (statistic = DEFAULT) <DEFAULT|CSTAT|WSTAT|CHI2> [string]
- Optimization statistic. DEFAULT uses the default statistic for all observations, which is CSTAT or the statistic specified in the observation definition XML file. CSTAT uses the C statistic for all observations, WSTAT uses the W statistic for all On/Off observations, and CHI2 uses the Chi squared statistic for all binned or stacked observations.
Standard parameters
- (chatter = 2) [integer]
- Verbosity of the executable:
chatter = 0: no information will be logged
chatter = 1: only errors will be logged
chatter = 2: errors and actions will be logged
chatter = 3: report about the task execution
chatter = 4: detailed report about the task execution
- (clobber = yes) [boolean]
- Specifies whether an existing output file should be overwritten.
- (debug = no) [boolean]
- Enables debug mode. In debug mode the executable will dump any log file output to the console.
- (mode = ql) [string]
- Mode of automatic parameters (default is ql, i.e. "query and learn").
- (logfile = cssens.log) [filename]
- Log filename.