Chandra X-Ray Observatory
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Last modified: December 2013

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

get_exposure

Context: data

Synopsis

Return the exposure time for a source or background data set

Syntax

get_exposure( [id, bkg_id] )

Description

The get_exposure() function returns the exposure time in seconds of a source or background PHA dataset, by data id or bkg_id.

  • id - the id of the data set to use; default=
  • 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 loaded

Example 1

sherpa> get_exposure()

When called with no arguments, get_exposure() returns the exposure time of the default data set.

sherpa> get_exposure()
56494.494371879999

Example 2

sherpa> get_exposure(id=2, bkg_id=1)

To return the exposure time of a background associated with a source data set, the background ID must be specified along with the data set ID. Here, the first background loaded for data set 2 is returned by get_exposure().

sherpa> get_exposure(id=2, bkg_id=1)
7854.4664748687001

Bugs

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

See Also

confidence
get_conf, get_covar, get_int_proj, get_int_unc, get_proj, get_reg_proj, get_reg_unc
contrib
get_chart_spectrum
data
get_areascal, get_arf, get_arf_plot, get_axes, get_backscal, get_bkg, get_bkg_plot, get_bkg_scale, get_coord, get_counts, get_data, get_data_plot, get_dep, get_dims, get_error, get_grouping, get_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror
filtering
get_filter
fitting
calc_stat_info, get_fit, get_stat_info
info
get_default_id, list_stats
methods
get_draws, get_iter_method_name, get_iter_method_opt, get_method
modeling
get_model, 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_response, get_source, get_source_component_image, get_source_component_plot, image_source
plotting
get_split_plot
psfs
get_kernel, get_psf
statistics
get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat
utilities
get_analysis, get_rate
visualization
get_ratio, get_resid, image_getregion

Last modified: December 2013
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The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email:   cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2017. All rights reserved.