set_arf

Context: data

Synopsis

Set the ARF for use by a PHA data set.

Syntax

set_arf(id, arf=None, resp_id=None, bkg_id=None)

Description

Set the effective area curve for a PHA data set, or its background.

Examples

Example 1

Copy the ARF from the default data set to data set 2:

>>> arf1 = get_arf()
>>> set_arf(2, arf1)

Example 2

Read in an ARF from the file 'bkg.arf' and set it as the ARF for the background model of data set "core":

>>> arf = unpack_arf('bkg.arf')
>>> set_arf('core', arf, bkg_id=1)

PARAMETERS

The parameters for this function are:

Parameter	Type information	Definition
id	int or str, optional	The data set to use. If not given then the default identifier is used, as returned by `get_default_id` .
arf		An ARF, such as returned by `get_arf` or `unpack_arf` .
resp_id	int, str, or None, optional	The identifier for the ARF within this data set, if there are multiple responses.
bkg_id	int, str, or None, optional	Set this to identify the ARF as being for use with the background.

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

If a PHA data set has an associated ARF - either from when the data was loaded or explicitly with the `set_arf` function - then the model fit to the data will include the effect of the ARF when the model is created with `set_model` or `set_source` . In this case the `get_source` function returns the user model, and `get_model` the model that is fit to the data (i.e. it includes any response information; that is the ARF and RMF, if set). To include the ARF explicitly, use `set_full_model` .

Bugs

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