Parameter Calculations

In this file we have the functions used to calculate the velocity, the velocity dispersion (broadening), and the flux as well as their uncertainties.

Fit Parameter Calculations

In this file we have the functions used to calculate the velocity, the velocity dispersion (broadening), and the flux as well as their uncertainties.

LUCI.LuciFitParameters.calculate_broad(ind, fit_sol, axis_step)

Calculate velocity dispersion

\sigma = (SPEED_OF_LIGHT*fit\_\sigma )/(fit\_vel)

where fit\_sigma is the gaussian broadening parameter found in the fit, and fit\_vel is the shifted position of the line in units of cm-1.

Note that we do NOT multiply by the axis_step. This kind of correction should have been done already in ORB!

Parameters:

  • ind – Index of line in lines

  • fit_sol – Solution from fitting algorithm

  • axis_step – Step due to correction factor (see LuciFit.calculate_correction)

Returns:

Velocity Dispersion of the Halpha line in units of km/s

LUCI.LuciFitParameters.calculate_broad_err(ind, fit_sol, axis_step, uncertainties)

Calculate velocity dispersion error We simply take the difference between the velocity dispersions with and without the uncertainty.

Parameters:

  • ind – Index of line in lines

  • fit_sol – Solution from fitting algorithm

  • axis_step – Step due to correction factor (see LuciFit.calculate_correction)

  • uncertaintes – Uncertainties from fitting algorithm

Returns:

Velocity Dispersion of the Halpha line in units of km/s

LUCI.LuciFitParameters.calculate_flux(line_amp, line_sigma, model_type, sinc_width)

Calculate flux value given fit of line See HowLuciWorks for calculations

Parameters:

  • line_amp – Amplitude of the line (un-normalized)

  • line_sigma – Sigma of the line fit

  • model_type – Fitting function (i.e. ‘gaussian’, ‘sinc’, or ‘sincgauss’)

  • sinc_width – Fixed with of the sinc function

Returns:

Flux of the provided line in units of erg/s/cm-2

LUCI.LuciFitParameters.calculate_flux_err(ind, fit_sol, uncertainties, model_type, sinc_width)

Calculate flux error

We simply take the difference between the fluxes with and without the uncertainty.

Parameters:

  • ind – Index of line in lines

  • fit_sol – Solution from fitting algorithm

  • uncertaintes – Uncertainties from fitting algoritm

  • model_type – Fitting function (i.e. ‘gaussian’, ‘sinc’, or ‘sincgauss’)

  • sinc_width – Fixed with of the sinc function

Returns:

Error of the provided line in units of ergs/s/cm-2

LUCI.LuciFitParameters.calculate_vel(ind, lines, fit_sol, line_dict)

Calculate velocity.

v = SPEED_OF_LIGHT*(l\_calc - l\_rest)/l\_calc

Where l\_calc = 1e7/fit\_vel and l\_rest is the rest wavelength of the line. fit\_vel is the shifted position of the line in units of cm-1.

Parameters:

  • ind – Index of line in lines

  • lines – Lines to be fit (e.x. [‘Halpha’])

  • fit_sol – Solution from fitting algorithm

  • line_dict – Dictionary of Line Names and their wavelengths in nm

Returns:

Velocity of the Halpha line in units of km/s

LUCI.LuciFitParameters.calculate_vel_err(ind, lines, fit_sol, line_dict, uncertainties)

Calculate velocity error

We simply take the difference between the velocities with and without the uncertainty.

Parameters:

  • ind – Index of line in lines

  • lines – Lines to be fit (e.x. [‘Halpha’])

  • fit_sol – Solution from fitting algorithm

  • line_dict – Dictionary of Line Names and their wavelengths in nm

  • uncertaintes – Uncertainties from fitting algoritm

Returns:

Velocity of the Halpha line in units of km/s