ReflectedRegionsFinder¶
-
class
gammapy.makers.
ReflectedRegionsFinder
(region, center, angle_increment='0.1 rad', min_distance='0 rad', min_distance_input='0.1 rad', max_region_number=10000, exclusion_mask=None, binsz='0.01 deg')[source]¶ Bases:
object
Find reflected regions.
This class is responsible for placing Reflected regions background for a given input region and pointing position. It converts to pixel coordinates internally assuming a tangent projection at center position.
If the center lies inside the input region, no reflected regions can be found.
If you want to make a background estimate for an IACT observation using the reflected regions method, see also
ReflectedRegionsBackgroundMaker
- Parameters
- region
SkyRegion
Region to rotate
- center
SkyCoord
Rotation point
- angle_increment
Angle
, optional Rotation angle applied when a region falls in an excluded region.
- min_distance
Angle
, optional Minimal distance between two consecutive reflected regions
- min_distance_input
Angle
, optional Minimal distance from input region
- max_region_numberint, optional
Maximum number of regions to use
- exclusion_mask
WcsNDMap
, optional Exclusion mask
- binsz
Angle
Bin size of the reference map used for region finding.
- region
Examples
>>> from astropy.coordinates import SkyCoord, Angle >>> from regions import CircleSkyRegion >>> from gammapy.makers import ReflectedRegionsFinder >>> pointing = SkyCoord(83.2, 22.7, unit='deg', frame='icrs') >>> target_position = SkyCoord(80.2, 23.5, unit='deg', frame='icrs') >>> theta = Angle(0.4, 'deg') >>> on_region = CircleSkyRegion(target_position, theta) >>> finder = ReflectedRegionsFinder(min_distance_input='1 rad', region=on_region, center=pointing) >>> finder.run() >>> print(finder.reflected_regions[0]) Region: CircleSkyRegion center: <SkyCoord (Galactic): (l, b) in deg ( 184.9367087, -8.37920222)> radius: 0.400147197682 deg
Methods Summary
find_regions
(self)Find reflected regions.
make_reference_map
(region, center[, binsz, …])Create empty reference map.
plot
(self[, fig, ax])Standard debug plot.
run
(self)Run all steps.
setup
(self)Compute parameters for reflected regions algorithm.
Methods Documentation
-
static
make_reference_map
(region, center, binsz='0.01 deg', min_width='0.3 deg')[source]¶ Create empty reference map.
The size of the map is chosen such that all reflected regions are contained on the image. To do so, the reference map width is taken to be 4 times the distance between the target region center and the rotation point. This distance is larger than the typical dimension of the region itself (otherwise the rotation point would lie inside the region). A minimal width value is added by default in case the region center and the rotation center are too close.
The WCS of the map is the TAN projection at the
center
in the coordinate system used by theregion
center.