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Fitting Options

fit_reg

Type: [tuple | list] of length (2,)
Default: (4400,5500)
Description: The minimum and maximum desired fitting wavelength in angstroms.

fit_area

Type: dict
Default: {}
Description: Defines the area to be fit for data cubes. See examples/muse_examples.py for usage.

mask_bad_pix

Type: bool
Default: False
Description: Mask pixels which the specified instrument has flagged as bad due to sky line subtraction or cosmic rays.

mask_emline

Type: bool
Default: False
Description: Mask any significant absorption and emission features relative to the continuum. This uses an automated iterative moving median filter of various sizes to detect significant flux differences between window sizes. Good for continuum fitting but tends to over mask lots of features near the edges of the spectrum.

fit_stat

Type: str
Default: "ML"
Description: The fit statistic used for the likelihood. Options:

  • "ML" for standard maximum likelihood (pixels weighted by noise with no noise scaling).
  • "OLS" for ordinary least-squares fitting (all pixels weighted by same amount).

n_basinhop:

Type: int
Default: 25
Description: Number of successive niter_success times the basinhopping algorithm needs to achieve a solution. The fit becomes much better with more success times, however this can increase the time to a solution significantly. Recommended 5-10.

reweighting

Type: bool
Default: True
Description: If true, BADASS will reweight the noise vector to achieve a reduced chi-squared ~ 1. This is done after the initial basinhopping fit, and applied to any bootstrapped uncertainties and MCMC fitting performed afterward. This does not affect the chi-squared ratio metric used in line and configuration testing, but does effect the amplitude-over-noise and SNR calculations in BADASS.

test_lines

Type: bool
Default: False
Description: Performs tests for lines. Options are specified in test_options.

max_like_niter

Type: int
Default: 10
Description: Number of bootstrapping iterations to perform after the initial basinhopping fit. This is a means to obtain uncertainties on parameters without performing MCMC fitting, however, do not produce as robust uncertainties as MCMC.

output_pars

Type: bool
Default: False
Convenience feature that prints out all free parameters.

cosmology

Type: dict
Default: {"H0":70.0, "Om0": 0.30})
Description: The flat Lambda-CDM cosmology assumed for calculating luminosities from fluxes.