Platefit

class pyplatefit.Platefit(contpars={}, linepars={}, eqwpars={}, mcmcpars={'nwalkers': 0, 'save_proba': False, 'steps': 0}, minpars={'method': 'least_square', 'xtol': 0.001})

Bases: object

This class is a poorman version of Platefit.

Initialise a Platefit object

Parameters:
contpars: dictionary

input parameters to be passed to Contfit constructor

linepars: dictionary

input parameters to be passed to Linefit constructor

minpars: dictionary

minimization parameters to be passed to Linefit constructor

mcmcpars: dictionary

EMCEE minimization parameters to be passed to Linefit constructor

eqwpars: dictionary

input parameters to be passed to EquivalentWidth constructor

Methods Summary

comp_eqw(spec, line_spec, z, lines_table)

compute equivalent width for emission lines

fit(spec, z[, ziter, fitcont, fitlines, ...])

Perform continuum and emission and absorption lines fit on a spectrum

fit_abslines(spec, z[, lsf])

Perform absorption lines fit on a continuum subtracted spectrum

fit_cont(spec, z, vdisp)

Perform continuum lines fit on a spectrum

fit_lines(line, z[, lsf])

Perform emission lines fit on a continuum subtracted spectrum

info(res)

print fitting info form fit

info_cont(res)

print a summary of continuum fit results

info_lines(res[, full_output])

print a summary of lines fit results

plot_cont(ax, res)

plot_lines(ax, res[, start, iden, minsnr, ...])

Methods Documentation

comp_eqw(spec, line_spec, z, lines_table)

compute equivalent width for emission lines

Parameters:
specmpdaf.obj.Spectrum

raw spectrum

line_specmpdaf.obj.Spectrum

continuum subtracted spectrum

zfloat

redshift

lines_table: astropy.table.Table

input/output lines table to be updated with eqw results

Returns:
None
The lines_table will be updated with the following columns:

  • EQW : Rest frame equivalent width in A, by convention emission lines have negative eqw

  • EQW_ERR : Standard error in equivalent width in A

fit(spec, z, ziter=False, fitcont=True, fitlines=True, fitabs=False, eqw=True, lsf=<function muse_lsf>, **kwargs)

Perform continuum and emission and absorption lines fit on a spectrum

Parameters:
specmpdaf.obj.Spectrum

continuum subtracted spectrum

zfloat

initial reshift

ziterbool

if True, a first emission line fit is performed to refine the redshift before a new continuum subtraction and a complete line fit is performed (to save computation time, eemce option is disactivated for the first fit), default false

fitcontbool

Fit and remove continuum prior to (absorption) line fitting.

fitlinesbool

Fit emission lines

fitabsbool

Fit absorption lines

eqwbool

Compute Equivalent Width

lsffunction

LSF model

**kwargskeyword arguments

Additional arguments passed to Linefit.fit function.

Returns:
resultdict

  • result[‘lines’]: astropy line table (see fit_lines)

  • result[‘ztable’]; astropy z table (see fit_lines)

  • result[‘spec’]: MPDAF original spectrum

  • result[‘cont_spec’]: MPDAF spectrum, estimated continuum in observed frame (cont_fit + smooth residuals)

  • result[‘cont_fit’]: MPDAF spectrum, fitted continuum in observed frame

  • result[‘line_spec’]: MPDAF spectrum, continnum removed spectrum in observed frame

  • result[‘line_fit’]: MPDAF spectrum, fitted emission lines in observed frame

  • result[‘line_initfit’]: MPDAF spectrum, starting solution for emission line fit in observed frame

  • result[‘poly_cont’]: MPDAF spectrum, polynomial continuum estimation

  • result[‘abs_fit’]: MPDAF spectrum, absorption line fit

  • result[‘spec_fit’]: MPDAF spectrum, fitted line+continuum (+absorption) in observed frame

  • result[‘dcont’]: return dictionary from fit_cont (see fit_cont)

  • result[‘dline’]: returned dictionary from fit_lines (see fit_lines)

fit_abslines(spec, z, lsf=<function muse_lsf>, **kwargs)

Perform absorption lines fit on a continuum subtracted spectrum

Parameters:
specmpdaf.obj.Spectrum

input spectrum

zfloat

reshift

lsffunction

LSF model

kwargskeyword arguments

Additional arguments passed to the fit_lines function.

Returns:
resdictionary

See Linefit.fit

fit_cont(spec, z, vdisp)

Perform continuum lines fit on a spectrum

Parameters:
linempdaf.obj.Spectrum

Continuum subtracted spectrum

zfloat

Reshift

vdispfloat

Velocity dispersion in km/s

Returns:
resultdict

  • result[‘table_spec’] astropy table with the following columns:

    • RESTWL: restframe vacuum wavelength

    • FLUX: data value in restframe

    • ERR: stddev of data value

    • CONTFIT: continuum fit (restframe)

    • CONTRESID: smoothed continuum residual (restframe)

    • CONT: continuum fit + residual

    • LINE: continuum subtracted

    • AIRWL: observed wavelength in air

  • result[‘cont_spec’]: MPDAF spectrum continuum (fit + smooth residual) in observed frame

  • result[‘cont_fit’]: MPDAF spectrum continuum (fit only) in observed frame

  • result[‘line_spec’]: MPDAF continuum subtracted spectrum in observed frame (spec - cont_spec)

  • result[‘success’]: True or False

  • result[‘z’]: Metallicity

  • result[‘ebv’]: E(B-V)

  • result[‘chi2’]: Chi2 fit

  • result[‘ages’]: fitted ages

  • result[‘weights’]: used weights

fit_lines(line, z, lsf=<function muse_lsf>, **kwargs)

Perform emission lines fit on a continuum subtracted spectrum

Parameters:
linempdaf.obj.Spectrum

continuum subtracted spectrum

zfloat

reshift

lsffunction

LSF model

kwargskeyword arguments

Additional arguments passed to the fit_lines function.

Returns:
resdictionary

See Linefit.fit

info(res)

print fitting info form fit

Parameters:
res:

results from fit

full_output: bool

if True write more information, default False

info_cont(res)

print a summary of continuum fit results

Parameters:
res:

results from fit_cont

info_lines(res, full_output=False)

print a summary of lines fit results

Parameters:
res:

results from fit_lines

full_output: bool

if True write more information, default False

plot_cont(ax, res)
plot_lines(ax, res, start=False, iden=True, minsnr=0, line=None, margin=5, dplot={'dl': 2.0, 'size': 10, 'y': 0.95})