# Background estimation (background)¶

## Introduction¶

gammapy.background contains methods to estimate and model background for specral, image based and cube analyses.

Most of the methods implemented are described in [Berge2007]. Section 7.3 “Background subtraction” and Section 7.4 “Acceptance determination and predicted background” in [Naurois2012] describe mostly the same methods as [Berge2007], except for the “2D acceptance model” described in Section 7.4.3.

## Getting Started¶

• TODO: example how to read and use a 2D and A 3D background model

### Using gammapy.background¶

If you’d like to learn more about using gammapy.background, read the following sub-pages:

## Reference/API¶

### gammapy.background Package¶

Background estimation and modeling methods.

#### Functions¶

 fill_acceptance_image(header, center, …[, …]) Generate a 2D image of a radial acceptance curve. ring_alpha(theta, r_in, r_out) Compute ring alpha, the inverse area factor. ring_area_factor(theta, r_in, r_out) Compute ring area factor. ring_background_estimate(pos, on_radius, …) Simple ring background estimate. ring_r_out(theta, r_in, area_factor) Compute ring outer radius.

#### Classes¶

 AdaptiveRingBackgroundEstimator(r_in, …[, …]) Adaptive ring background algorithm. BackgroundEstimate(on_region, on_events, …) Container class for background estimate. EnergyOffsetArray(energy, offset[, data, …]) Energy offset dependent array. EnergyOffsetBackgroundModel(energy, offset) EnergyOffsetArray background model. FOVCube([coordx_edges, coordy_edges, …]) Field of view cube. FOVCubeBackgroundModel([counts_cube, …]) Field of view (FOV) cube background model. FoVBackgroundEstimator([norm]) Basic class to perform FoV background estimation. GaussianBand2D(table[, spline_kwargs]) Gaussian band model. OffDataBackgroundMaker(data_store[, outdir, …]) OffDataBackgroundMaker class. ReflectedRegionsBackgroundEstimator(…) Reflected Regions background estimator. ReflectedRegionsFinder(region, center[, …]) Find reflected regions. RingBackgroundEstimator(r_in, width[, …]) Ring background method for cartesian coordinates.