Synopsis
Include a model of the Chandra ACIS pile up when fitting PHA data.
Syntax
set_pileup_model(id, model=None)
Description
Chandra observations of bright sources can be affected by pileup, so that there is a non-linear correlation between the source model and the predicted counts. This process can be modelled by including the `jdpileup` model for a data set, using the `set_pileup_model` .
Example
Plot up the model (an xsphabs model multiplied by a powlaw1d component) and then overplot the same expression but including the effects of pile up in the Chandra ACIS instrument:
>>> load_pha('src.pi')
>>> set_source(xsphabs.gal * powlaw1d.pl)
>>> plot_model()
>>> set_pileup_model(jdpileup.jpd)
>>> plot_model(overplot=True)PARAMETERS
The parameters for this function are:
| Parameter | Type information | Definition |
|---|---|---|
| id | int or str, optional | The data set containing the source expression. If not given then the default identifier is used, as returned by `get_default_id` . |
| model | an instance of the jdpileup class |
Notes
The function does not follow the normal Python standards for parameter use, since it is designed for easy interactive use. When called with a single un-named argument, it is taken to be the `model` parameter. If given two un-named arguments, then they are interpreted as the `id` and `model` parameters, respectively.
This is a generic function, and can be used to model other non-linear detector effects, but at present the only available model is for the ACIS pile up provided by the jdpileup 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_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_source_plot, set_areascal, set_arf, set_backscal, set_bkg, set_coord, set_counts, set_data, set_dep, set_exposure, set_grouping, set_quality, set_rmf, set_staterror, set_syserror
- filtering
- set_filter
- info
- list_model_ids, list_pileup_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, delete_pileup_model, get_model, get_model_autoassign_func, 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_source, get_source_component_image, get_source_component_plot, get_source_contour, get_source_image, get_source_plot, image_model, image_model_component, image_source, image_source_component, integrate, link, load_table_model, load_template_interpolator, load_template_model, load_user_model, normal_sample, reset, save_model, save_source, set_bkg_model, set_bkg_source, set_full_model, set_model, set_model_autoassign_func, set_par, set_source, t_sample, uniform_sample
- plotting
- get_cdf_plot, get_pdf_plot, 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, image_setregion