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Synopsis:
Generates an exposure map, or a set of exposure maps for different energies, from a livetime cube written by gtltcube.
Usage: gtexpcube infile cmfile outfile irfs nxpix nypix pixscale coordsys xref yref axisrot proj emin emax enumbins
Prerequisites
Input Files:
- Livetime or Exposure cube FITS file from gtltcube
- Optionally, a counts map FITS file from gtbin, for which gtexpcube should match the coordinate projection and gridding. The counts map also specifies the effective area response functions for gtexpcube to use.
Links
General Parameters
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infile [file] |
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Exposure or Livetime cube file. FITS file containing livetime as a function of sky position and off-axis angle. This file can be generated by gtltcube, or obtained from SLAC's Data Portal. (See gtltcube help.) |
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evfile [file] |
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Name of the input event FITS file, which can be obtained from SLAC's data portal. |
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cmfile [file] |
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Count map input FITS file. This file is generated using gtbin. (See gtbin help.) Select "NONE" if you wish to specify the map geometry from parameters (nxpix, nypix, xref, yref, enumbins, etc). |
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outfile [file] |
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Exposure map output FITS file name. |
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irfs [string] |
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The instrument response (PSF, effective area, energy resolution) is a function of energy, inclination angle (the angle between the source and the LAT normal), and photon category. Since the LAT usually surveys the sky, a source is observed at different inclination angles. Each count is therefore characterized by a different instrument response function (IRF). |
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nxpix = 1 [int] |
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Number of pixels in the horizontal dimension in the output image. If proj is "CAR","AIT", or "ZEA", you can use the default value "1" for full sky. |
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nypix = 1 [int] |
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Number of pixels in the vertical dimension in the output image. If proj is "CAR","AIT", or "ZEA", you can use the default value "1" to create a full sky, or you can use the same value as specified for nxpix. |
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pixscale = 0.5 [float] |
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Image scale (in degrees/pixel). (default: 0.5) |
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coordsys = "CEL" [string: CEL|GAL] |
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Coordinate system. If you choose CEL, you will be prompted for RA and DEC (J2000) in the xref and yref parameters; if you choose GAL you will be prompted for l and b coordinates. |
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xref = 0. [float] |
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Horizontal position of the center of the image; either RA in celestial coordinates or l in Galactic coordinates (decimal degrees). (default: 0) |
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yref = 0. [float] |
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Vertical position of the center of the image; either DEC in celestial coordinates or b in Galactic coordinates (decimal degrees). (default: 0) |
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axisrot = 0. [float] |
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Rotation angle desired for the image in degrees. (default: 0) |
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proj = "AIT" [string: AIT|ARC|CAR|ZEA|GLS|MER|NCP|SIN|STG|TAN] |
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Desired coordinate projection: Aitoff [AIT], Zenithal equal- area [ZEA], Zenithal equidistant [ARC], Plate Carree [CAR], Sanson-Flamsteed [GLS], Mercator [MER], North-Celestial-Pole [NCP], Slant orthographic [SIN], Stereographic [STG], Gnomonic [TAN]. See Calabretta & Greisen 2002, A&A, 395, 1077 for definitions of the projections. Must be AIT, ZEA, or CAR for auto full sky. The default value is AIT. |
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emin = 30 [float] |
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Lower boundary for first energy bin in MeV. It must be larger than, or equal
to, 30 MeV. (default: 30 MeV) |
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emax = 200000 [float] |
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Upper boundary for last energy bin in MeV. It must be less than, or equal to,
200 GeV. (default: 200 GeV) |
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enumbins = 8 [int] |
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Number of logarithmically spaced energy bins spanning emin to emax.
(default: 8) |
Hidden parameters
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(bincalc = "CENTER") [string: CENTER|EDGE] |
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Allows you to choose how energy layers are computed from the count map (cmfile parameter) energy bounds. The options are CENTER and EDGE.This is a hidden parameter. (default: as of 11/30/2010 the default was set to CENTER, but will be changed to EDGE in a future release)
Troubleshooting Tip (11-30-2010): If you are experiencing a failure when running gtsrcmaps while performing a binned likelihood analysis, check that this hidden parameter is set to EDGE at the command line when computing the 3D exposure map using gtexpcube. If necessary, you can set this parameter from the command line when you launch gtexpcube; for example:
prompt> gtexpcube bincalc=EDGE
Update (12-17-2010) — When performing a binned likelihood analysis: A new tool, gtexpcube2 has been added for use in binned analysis with the Likelihood tools. This application replaces the "on-the-fly" binned exposure map calculation that was provided by gtsrcmaps, and it replaces the gtexpcube application from the map_tools package. The old gtexpcube application should not be used for Likelihood analysis any longer. (See ScienceTools-09-20-00 New Feature Summary in confluence.) |
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(table = "Exposure") |
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Exposure cube extension. This is a hidden parameter. (default: "Exposure") |
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(evtable = "EVENTS") |
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FT1 events extension. |
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(chatter = 2) |
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Output verbosity. This is a hidden parameter. (default: 2) |
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(clobber = yes) |
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If true, an existing file of the same name will be overwritten. This is a hidden parameter. yes) |
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(debug = no) |
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Activate debugging mode. This is a hidden parameter. (default: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. |
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(gui = no) |
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If "yes" is specified, the Graphical User Interface (GUI) mode is activated.
This is a hidden parameter. (default: no) |
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(mode = "ql") |
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Mode of automatic parameters. This is a hidden parameter. (default: ql) |
| Last updated by: Analia Cillis and Chuck Patterson 03/20/2006 |
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