Last modified: December 2018

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

fm

Context: models

Synopsis

UV extinction curve: Fitzpatrick and Massa 1988.

Syntax

fm

Description

The UV extinction is calculated using [1] . This model is intended to be used to modify another model (e.g. by multiplying the two together). It is for use when the independent axis is in Angstrom.


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.ebv      thawed          0.5 -3.40282e+38  3.40282e+38           
   mdl.x0       thawed          4.6 -3.40282e+38  3.40282e+38           
   mdl.width    thawed         0.06 -3.40282e+38  3.40282e+38           
   mdl.c1       thawed          0.2 -3.40282e+38  3.40282e+38           
   mdl.c2       thawed          0.1 -3.40282e+38  3.40282e+38           
   mdl.c3       thawed         0.02 -3.40282e+38  3.40282e+38           
   mdl.c4       thawed          0.1 -3.40282e+38  3.40282e+38           

ATTRIBUTES

The attributes for this object are:

ebv

E(B-V)

x0

Position of the Drude bump.

width

Width of the Drude bump.

c1

The intercept of the linear term.

c2

The slope of the linear term.

c3

Normalization of the Drude bump.

c4

Normalization of the FUV curvature.

Notes

When evaluated on a binned grid, the lower-edges of the bins are used for the calculation.

References


Bugs

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

See Also

models
ccm, lmc, seaton, sm, smc, xgal