Last modified: December 2020

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

load_bkg_arf

Context: data

Synopsis

Load an ARF from a file and add it to the background of a PHA data set.

Syntax

load_bkg_arf(id, arg=None)

id - int or str, optional

Description

Load in the ARF to the background of the given data set. It is only for use when there is only one background component, and one response, for the source. For multiple backgrounds or responses, use `load_arf` .


Examples

Example 1

Use the contents of the file 'bkg.arf' as the ARF for the background of the default data set.

>>> load_bkg_arf('bkg.arf')

Example 2

Set 'core_bkg.arf' as the ARF for the background of data set 'core':

>>> load_bkg_arf('core', 'core_bkg.arf')

PARAMETERS

The parameters for this function are:

Parameter Definition
id The data set to use. If not given then the default identifier is used, as returned by `get_default_id` .
arg Identify the ARF: a file name, or a data structure representing the data to use, as used by the I/O backend in use by Sherpa: a tablecrate for crates, as used by CIAO, or a list of AstroPy HDU objects.

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 `arg` parameter. If given two un-named arguments, then they are interpreted as the `id` and `arg` parameters, respectively. The remaining parameters are expected to be given as named arguments.

The `minimum_energy` setting of the `ogip` section of the Sherpa configuration file determines the behavior when an ARF with a minimum energy of 0 is read in. The default is to replace the 0 by the value 1e-10, which will also cause a warning message to be displayed.


Bugs

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

See Also

data
dataspace1d, dataspace2d, datastack, fake, get_arf, get_bkg, get_bkg_arf, get_bkg_model, get_bkg_rmf, get_bkg_source, load_arf, load_arrays, load_ascii, load_bkg, load_bkg_rmf, load_data, load_grouping, load_image, load_multi_arfs, load_multi_rmfs, load_pha, load_quality, load_rmf, load_staterror, load_syserror, load_table, pack_image, pack_pha, pack_table, set_arf, unpack_arf, unpack_arrays, unpack_ascii, unpack_bkg, unpack_data, unpack_image, unpack_pha, unpack_rmf, unpack_table
filtering
load_filter
info
get_default_id, list_bkg_ids, list_data_ids, list_response_ids
modeling
add_model, add_user_pars, get_response, load_table_model, load_template_interpolator, load_template_model, load_user_model, save_model, save_source
plotting
plot_arf
saving
save_arrays, save_data, save_delchi, save_error, save_filter, save_grouping, save_image, save_pha, save_quality, save_resid, save_staterror, save_syserror, save_table
statistics
load_user_stat