The synthetic module

The synthetic module#

This submodule has been designed to provide tool to create synthetic PSD.

apollinaire.synthetic.create_synthetic_psd(freq, pkb=None, splittings=None, back=None, param_back=None, n_harvey=2, wdw=None, feature=None, instr='geometric', asym_profile='nigam-kosovichev', use_sinc=False, entropy=None, noise_free=False, fit_amp=False)#

Create a synthetic psd vector from a frequency vector, modes parameters from a pkb arrays and, optionnally, a background profile.

Parameters:

  • freq (ndarray) – input frequency vector on which to compute the synthetic PSD vector.

  • pkb (ndarray) – The pkb array with the mode parameters.

  • splittings – Either a multi-level dictionary or a 3d-array. If it is a dictionary, d[n][l][m] provides the splitting corresponding to the m-component of the mode of degree l and order n. If it is an array, the first dimension must match pkb.shape[0], the second dimension be int (pkb[:,1].max()) (that is the maximum specified angular degree l, lmax), and the third dimension, 2*lmax+1. If provided, splittings informations included in the pkb array will be ignored when generating the spectrum.

  • back (ndarray) – stellar background array, of same length as freq. Optional, default None.

  • param_back (ndarray) – stellar background parameters used to build the background vector. Will be used only if back is None. Optional, default None.

  • n_harvey (int) – number of Harvey law of the background profile. Optional, default 2.

  • wdw (array) – observation window to use to convolute the modes profile in the model.

  • feature (ndarray) – array of same length as freq, to be used to add any additionnal feature to the spectrum. This array will be summed to the model array before adding the chi2 noise. Optional, default None.

  • instr (str) – instrument to consider to compute m-height ratios. Possible argument : geometric, kepler, golf, virgo. Optional, default geometric.

  • use_sinc (bool) – if set to True, mode profiles will be computed using cardinal sinus and not Lorentzians. No asymmetry term will be used if it is the case. Optional, default False.

  • asym_profile (str) – depending on the chosen argument, asymmetric profiles will be computed following Korzennik 2005 (korzennik) or Nigam & Kosovichev 1998 (nigam-kosovichev). Default nigam-kosovichev.

  • entropy (int) – entropy value to seed the random generator.

  • noise_free (bool) – if set to True, the function will return only an ideal model without added noise. Optional, default False.

Returns:

the synthetic PSD vector and the entropy value (for reproductibility) as a tuple.

Return type:

tuple