Summary of Commands

The following is a list of the commands available in XSPEC, together with a brief description of the purpose of each. The commands have been categorized under six headings: Control, Data, Fit, Model, Plot, Script, and Setting. The Control commands contain the interface with the operating system: they cause commands to be executed, or user input written to disk, or control how much is output. The Data commands manipulate the data being analyzed, by reading data into the program or replacing spectra or their ancillary detector, background, correction, or efficiency (auxiliary response) arrays. Additionally, data commands control the channels under analysis. The fit commands invoke the fitting routines, modify their behavior by interchanging fitting algorithms or statistics in use, fixing parameters, or perform statistical testing. The Model commands create or manipulate the model, adding or editing components, modifying parameters, or alternatively performing analytical calculations from a model. The Plot commands deal with all aspects of plotting. The scripts are auto-loaded Tcl scripts that can be used in the same ways as commands. Finally the Setting commands sets variables that affect theoretical models.

Command Category Description
abund SETTING Set the abundance table.
addcomp MODEL Add a component to the model.
addline MODEL Add lines to a model
arf DATA Read an auxiliary response file.
autosave CONTROL Periodically save the XSPEC status.
backgrnd DATA Reset the files to be used for background subtraction.
bayes FIT Set up for Bayesian inference.
chain FIT Run a Monte Carlo Markov Chain.
chatter CONTROL Control the verbosity of XSPEC.
corfile DATA Reset the files to be used for background correction.
cornorm DATA Reset the normalization to be used in correcting the background.
cosmo SETTING Set $H_0$, $q_0$, and $\Lambda_0$
cpd PLOT Alias for setplot device.
data DATA Input one or more PHA data files.
delcomp MODEL Delete a component from the model.
diagrsp DATA Diagonalize the current response for an ideal response.
dummyrsp MODEL Create a dummy response, covering a given energy range.
editmod MODEL Add, delete, or replace one component in the model.
energies MODEL Specify new energy binning for model fluxes.
eqwidth MODEL Calculate a model component2019s equivalent width.
error (rerror) FIT Determine a single parameter confidence region. rerror is for response parameters.
exec CONTROL Execute a shell command from within XSPEC.
exit CONTROL Wind up any hardcopy plots and exit from XSPEC.
extend MODEL This is now obsolete. See energies command.
fakeit DATA Produce simulated data files for sensitivity studies.
fit FIT Find the best fit model parameters.
flux MODEL Calculate the current model's flux over an energy range.
freeze (rfreeze) FIT Do not allow a model parameter to vary during the fit. rfreeze is for response parameters.
ftest FIT Calculate the F-statistic between two model fits
gain MODEL Perform a simple modification of the response gain.
goodness FIT Monte Carlo calculation of goodness-of-fit.
hardcopy PLOT Spool the current plot to the printer.
help CONTROL Obtain help on XSPEC commands.
identify MODEL List possible lines in the specified energy range.
ignore DATA Ignore a range of PHA channels in future fit operations.
initpackage MODEL Compile, build, and initialize a package of local models.
iplot PLOT As plot command but interactive using PLT.
lmod MODEL Load a package of local models.
log CONTROL Open the log file to save output.
lrt SCRIPT Likelihood ratio test between two models.
lumin MODEL Calculate the current model's luminosity over a given rest frame energy range and redshift.
margin FIT MCMC probability distribution.
mdefine MODEL Define a simple model using an arithmetic expression.
method SETTING Set the minimization method.
model (rmodel) MODEL Define the model to be used when fitting the data.
modid MODEL Guess line IDs in the model.
multifake SCRIPT Perform many iterations of fakeit and save the results in a FITS file.
newpar (rnewpar) MODEL Modify the model parameters. rnewpar is for response parameters
notice DATA Restore a range of PHA channels for future operations.
parallel CONTROL Enable parallel processing for particular tasks in XSPEC.
plot PLOT Plot various information on the current plot device.
query CONTROL Switch on/off prompt to continue fitting.
quit CONTROL An alias for exit
renorm FIT Adjust the model norms, and/or control automatic renorming.
rescalecov SCRIPT Rescale the covariance matrix used in the proposal chain command.
response DATA Reset the files used to determine the detector responses.
save CONTROL Save aspects of the current state to a command file.
script CONTROL Open the script file to save all commands input.
setplot PLOT Modify the plot device and other values used by the plot routines.
show CONTROL Display current file and model information.
simftest SCRIPT Generate simulated datasets to estimate the F-test probability for adding a model component.
source CONTROL Execute a script file.
statistic SETTING Change the fit statistic in use.
steppar FIT Step through a range of parameter values; perform a fit at each step.
syscall CONTROL Run a shell command.
systematic MODEL Set the model systematic error.
tclout CONTROL write xspec data to a tcl variable
tcloutr CONTROL tclout with return value
thaw (rthaw) FIT Allow a model parameter to vary during the fit. rthaw is for response parameters
time CONTROL Display elapsed time and other statistical information.
uncertain FIT Alias for error
untie (runtie) MODEL Untie linked parameters. runtie is for response parameters.
version CONTROL Print XSPEC version and build date/time
weight FIT Change the weighting function used for chi-squared fits.
writefits SCRIPT Write information about the current fit and errors to a FITS file.
xsect SETTING Change the photoelectric absorption cross-sections in use.
xset SETTING Modify a number of XSPEC internal switches

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Last modified: Tuesday, 28-May-2024 10:09:22 EDT