Data Formats¶
Note
Since November 2015 there is the Data formats for gamma-ray astronomy project. This page contains extra information about which formats we support in Gammapy and which class corresponds to which format.
Note
In datasets - Dataset access you find example gamma-ray datasets, some in the formats described here.
Where available and useful existing standards are used, e.g. for spectral data
the X-ray community has developed the PHA, ARF and RMF file formats
and they have developed powerful tools to work with data in that format.
Overview¶
Here’s an overview of the file formats supported by Gammapy and Gammalib:
| Type | Format Name | Gammapy | Gammalib |
|---|---|---|---|
| Events | EVENTS | EventList |
GEventList |
| Effective area | AEFF_2D | EffectiveAreaTable2D |
GCTAAeff2D |
| Effective area | ARF | EffectiveAreaTable |
GCTAAeffArf |
| Energy dispersion | EDISP_2D | EnergyDispersion2D |
GCTAEdisp2D |
| Energy dispersion | RMF | EnergyDispersion |
GCTAEdispRMF |
| PSF | PSF_2D_GAUSS | EnergyDependentMultiGaussPSF |
GCTAPsf2D |
| PSF | PSF_2D_KING | PSFKing |
GCTAPsfKing |
| PSF | no spec available | TablePSF |
GCTAPsfVector |
| PSF | gtpsf output | EnergyDependentTablePSF |
N/A |
| PSF | psf_table | PSF3D |
GCTAPsfTable |
| PSF | no spec available | N/A | GCTACubePsf |
| Background | BACKGROUND_3D | Background3D |
GCTABackground3D |
| Background | BACKGROUND_2D | Background2D |
N/A |
| Background | no spec available | N/A | GCTAModelRadialAcceptance |
| Background | no spec available | N/A | GCTACubeBackground |
| Exposure | EXPOSURE_3D | Map |
GCTACubeExposure |
| Counts | 3D | Map |
GCTAEventCube |
| Counts | Image | Map |
GSkyMap |
| Counts | PHA | CountsSpectrum |
GPha |
Notes¶
- The Gammalib docs contain a nice overview of IRFs here and detailed explanations of some IRF here.
- We probably should unify / shorten the IRF class names in Gammapy.
- There’s quite a few classes in Gammapy that don’t have a well-defined format. We should add a way to serialise every class and document the format for easier interop.
- Maybe add info which format is used by Fermi, HESS HD/PA, CTA?
- For every format there should be one or several test data files. This could even be in a repo that’s shared by Gammalib / Gammapy.