Last modified: December 2018

URL: http://cxc.harvard.edu/sherpa/ahelp/schechter.html
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AHELP for CIAO 4.11 Sherpa v1

schechter

Context: models

Synopsis

One-dimensional Schecter model function.

Syntax

schechter

Description

This model is for integrated data grids only.


Example

>>> create_model_component("schechter", "mdl")
>>> print(mdl)

Create a component of the schechter model and display its default parameters. The output is:

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.alpha    thawed           10 -3.40282e+38  3.40282e+38           
   mdl.ref      thawed            1 -3.40282e+38  3.40282e+38           
   mdl.norm     thawed            1 -3.40282e+38  3.40282e+38           

ATTRIBUTES

The attributes for this object are:

alpha

The slope of the power-law component.

ref

The reference position, which controls the switch from the power-law to the exponential.

norm

The normalisation of the model.

Notes

The functional form of the model for grids is:

f(xlo,xhi) = norm * (xlo / ref)^alpha
                  * exp(-xlo / ref)
                  * (xhi - xlo) / ref

and for points the model is:

f(x) = 0

Bugs

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