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Last modified: December 2013

URL: http://cxc.harvard.edu/sherpa/ahelp/set_bkg_model.html
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AHELP for CIAO 4.9 Sherpa v1

set_bkg_model

Context: modeling

Synopsis

Set a background model expression

Syntax

set_bkg_model( [id], model, [bkg_id] )

Description

The set_bkg_model command sets the model expression to be used for fitting a background dataset.

To manually set the complete convolved model expression to be used for fitting a background data set - i.e., other than automatically with set_bkg_model - use the set_full_model and set_bkg_full_model commands (see "ahelp set_full_model").

  • id - the id of the dataset; if not given, uses the default dataset id (id=1 by default, see "ahelp get_default_id")
  • model - the model expression; for a list of all available models, see "ahelp models"
  • bkg_id - the id of the background to use, e.g. if more than one background is associated with the data; default is the first background dataset

Example 1

sherpa> set_bkg_model(xsphabs.abs1*powlaw1d.p1)

The model for the first background of the default dataset is set to photo-electric absorption times a 1-D powerlaw.

Example 2

sherpa> set_bkg_model(2, gauss2d.g2d, bkg_id=2)

The model for the second background of dataset id=2 is set to a gauss2d model.

Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

confidence
set_conf_opt, set_covar_opt, set_proj_opt
data
get_bkg_plot, set_areascal, set_arf, set_backscal, set_bkg, set_coord, set_counts, set_data, set_exposure, set_grouping, set_quality, set_rmf, set_staterror, set_syserror
filtering
set_filter
info
list_model_ids, show_bkg_model, show_bkg_source
methods
set_iter_method, set_iter_method_opt, set_method, set_method_opt
modeling
add_model, add_user_pars, clean, create_model_component, delete_bkg_model, delete_model, delete_model_component, get_model, get_model_autoassign_func, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_order_plot, get_par, get_pileup_model, get_source, get_source_component_image, get_source_component_plot, image_model, image_model_component, image_source, image_source_component, integrate, integrate1d, link, load_table_model, load_template_model, load_user_model, normal_sample, reset, save_model, save_source, set_full_model, set_model_autoassign_func, set_par, set_pileup_model, set_source, set_xsabund, set_xscosmo, set_xsxsect, set_xsxset, t_sample, uniform_sample
plotting
get_lrt_plot, get_lrt_results, get_pvalue_plot, get_pvalue_results, plot_cdf, plot_model, plot_model_component, plot_pdf, plot_pvalue, plot_scatter, plot_source, plot_source_component, plot_trace
psfs
delete_psf, load_conv
saving
save_delchi, save_resid
statistics
set_prior, set_sampler, set_sampler_opt, set_stat
utilities
calc_chisqr, calc_energy_flux, calc_model_sum, calc_photon_flux, calc_source_sum, calc_stat, eqwidth, set_analysis, set_default_id
visualization
contour_model, contour_ratio, contour_resid, get_ratio, get_resid, image_setregion

Last modified: December 2013
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