Chandra X-Ray Observatory (CXC)
Skip to the navigation links
Last modified: June 2012

URL: http://cxc.harvard.edu/sherpa/logabsorption.html
Jump to: Description · Bugs · See Also


AHELP for CIAO 4.4 Sherpa v2

logabsorption

Context: models

Synopsis

Logarithmic absorption model

Description

A logarithmic absorption model, taking the functional form:

alpha = log(2) / log(1 + fwhm / 2 / c)

if x >= pos,

f(x) = exp [-(tau * (x / pos)**alpha)]

and if x < pos,

f(x) = exp [-(tau * (x / pos)**(-1.0*alpha))]

LogAbsorption Parameters

Number Name Description
1 fwhm FWHM of the feature, in Angstroms
2 pos Center of the feature, in Angstroms
3 tau Optical depth

Bugs

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

See Also

models
absorptionedge, absorptiongaussian, absorptionlorentz, absorptionvoigt, accretiondisk, atten, bbody, bbodyfreq, beta1d, beta2d, blackbody, box1d, box2d, bpl1d, bremsstrahlung, brokenpowerlaw, ccm, const1d, const2d, cos, delta1d, delta2d, dered, devaucouleurs2d, edge, emissiongaussian, emissionlorentz, emissionvoigt, erf, erfc, exp, exp10, fm, gauss1d, gauss2d, hubblereynolds, jdpileup, linebroad, list_model_components, list_models, lmc, log, log10, logemission, logparabola, lorentz1d, lorentz2d, models, normbeta1d, normgauss1d, normgauss2d, opticalgaussian, poisson, polynom1d, polynom2d, polynomial, powerlaw, powlaw1d, recombination, scale1d, scale2d, schechter, seaton, sersic2d, sin, sm, smc, sqrt, stephi1d, steplo1d, tablemodel, tan, xgal, xs, xsabsori, xsacisabs, xsapec, xsbapec, xsbbody, xsbbodyrad, xsbexrav, xsbexriv, xsbkn2pow, xsbknpower, xsbmc, xsbremss, xsbvapec, xsbvvapec, xsc6mekl, xsc6pmekl, xsc6pvmkl, xsc6vmekl, xscabs, xscemekl, xscevmkl, xscflow, xscompbb, xscompls, xscompps, xscompst, xscompth, xscomptt, xsconstant, xscplinear, xscutoffpl, xscyclabs, xsdisk, xsdiskbb, xsdiskir, xsdiskline, xsdiskm, xsdisko, xsdiskpbb, xsdiskpn, xsdust, xsedge, xseplogpar, xseqpair, xseqtherm, xsequil, xsexpabs, xsexpdec, xsexpfac, xsezdiskbb, xsgabs, xsgadem, xsgaussian, xsgnei, xsgrad, xsgrbm, xshighecut, xshrefl, xskerrbb, xskerrd, xskerrdisk, xslaor, xslaor2, xslogpar, xslorentz, xsmeka, xsmekal, xsmkcflow, xsnei, xsnotch, xsnpshock, xsnsa, xsnsagrav, xsnsatmos, xsnsmax, xsnteea, xsnthcomp, xsoptxagn, xsoptxagnf, xspcfabs, xspegpwrlw, xspexmon, xspexrav, xspexriv, xsphabs, xsplabs, xsplcabs, xsposm, xspowerlaw, xspshock, xspwab, xsraymond, xsredden, xsredge, xsrefsch, xssedov, xssirf, xssmedge, xsspexpcut, xsspline, xssrcut, xssresc, xssss_ice, xsstep, xsswind1, xstbabs, xstbgrain, xstbvarabs, xsuvred, xsvapec, xsvarabs, xsvbremss, xsvequil, xsvgadem, xsvgnei, xsvmcflow, xsvmeka, xsvmekal, xsvnei, xsvnpshock, xsvphabs, xsvpshock, xsvraymond, xsvsedov, xsvvapec, xswabs, xswndabs, xsxion, xszbbody, xszbremss, xszdust, xszedge, xszgauss, xszhighect, xszigm, xszpcfabs, xszphabs, xszpowerlw, xszredden, xszsmdust, xsztbabs, xszvarabs, xszvfeabs, xszvphabs, xszwabs, xszwndabs, xszxipcf

Last modified: June 2012
CXC logo

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email: cxcweb@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2012. All rights reserved.