Last modified: December 2020

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/get_backscal.html
AHELP for CIAO 4.13 Sherpa v1

get_backscal

Context: data

Synopsis

Return the BACKSCAL scaling of a PHA data set.

Syntax

get_backscal(id=None, bkg_id=None)

id - int or str, optional
bkg_id - int or str, optional

Description

Return the BACKSCAL setting [1] for the source or background component of a PHA data set.


Example

>>> get_backscal()
7.8504301607718007e-06
>>> get_backscal(bkg_id=1)
0.00022745132446289

PARAMETERS

The parameters for this function are:

Parameter Definition
id The identifier for the data set to use. If not given then the default identifier is used, as returned by `get_default_id` .
bkg_id Set to identify which background component to use. The default value ( none ) means that the value is for the source component of the data set.

Return value

The return value from this function is:

backscal -- The BACKSCAL value, which can be a scalar or a 1D array.

Notes

The BACKSCAL value can be defined as the ratio of the area of the source (or background) extraction region in image pixels to the total number of image pixels. The fact that there is no ironclad definition for this quantity does not matter so long as the value for a source dataset and its associated background dataset are defined in the similar manner, because only the ratio of source and background BACKSCAL values is used. It can be a scalar or be an array.

References


Bugs

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

See Also

confidence
get_conf, get_conf_results, get_covar, get_covar_opt, get_covar_results, get_covariance_results, get_int_proj, get_int_unc, get_proj, get_proj_opt, get_proj_results, get_projection_results, get_reg_proj, get_reg_unc
contrib
get_chart_spectrum, get_marx_spectrum
data
get_areascal, get_arf, get_arf_plot, get_axes, get_bkg, get_bkg_arf, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_rmf, get_bkg_scale, get_bkg_source, get_bkg_source_plot, get_coord, get_counts, get_data, get_data_contour, get_data_contour_prefs, get_data_image, get_data_plot, get_data_plot_prefs, get_dep, get_dims, get_error, get_exposure, get_grouping, get_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror, set_backscal
filtering
get_filter
fitting
calc_stat_info, get_stat_info
info
get_default_id, list_stats
methods
get_draws, get_iter_method_name, get_iter_method_opt, get_method, get_method_name, get_method_opt
modeling
get_model, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_num_par_frozen, get_num_par_thawed, get_order_plot, get_par, get_pileup_model, get_response, get_source, get_source_component_image, get_source_component_plot, get_source_contour, get_source_image, get_source_plot, image_source
plotting
get_split_plot
psfs
get_psf, get_psf_contour, get_psf_image, get_psf_plot
statistics
get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat, get_stat_name
utilities
get_analysis, get_rate
visualization
image_getregion