piXedfit_model

A description about the parameters involved in the SED modeling is given here.

piXedfit.piXedfit_model.generate_modelSED_photo(filters, sp=None, imf_type=1, duste_switch=0, add_neb_emission=1, dust_law=1, sfh_form=4, add_agn=0, add_igm_absorption=0, igm_type=0, smooth_velocity=True, sigma_smooth=0.0, smooth_lsf=False, lsf_wave=None, lsf_sigma=None, cosmo='flat_LCDM', H0=70.0, Om0=0.3, params_val={'dust1': 0.5, 'dust2': 0.5, 'dust_index': -0.7, 'gas_logu': -2.0, 'gas_logz': None, 'log_age': 1.0, 'log_alpha': 0.1, 'log_beta': 0.1, 'log_fagn': -3.0, 'log_gamma': -2.0, 'log_mass': 0.0, 'log_qpah': 0.54, 'log_t0': 0.4, 'log_tau': 0.4, 'log_tauagn': 1.0, 'log_umin': 0.0, 'logzsol': 0.0, 'z': 0.001})

Function for generating a model photometric SED given some parameters.

Parameters:

filters – List of photometric filters. The list of filters recognized by piXedfit can be accessed using piXedfit.utils.filtering.list_filters(). Please see this page for information on managing filters that include listing available filters, adding, and removing filters.
sp – (optional, default: None) Initialization of FSPS, such as sp=fsps.StellarPopulation(). This is intended for rapid generation of model spectra from FSPS. However, this input is optional. If sp=None, FSPS will be called everytime this function is called.
imf_type – Choice for the IMF. Choices are: 0 for Salpeter(1955), 1 for Chabrier(2003), and 2 for Kroupa(2001).
duste_switch – Choice for switching on (value: 1) or off (value: 0) the dust emission modeling.
add_neb_emission – Choice for switching on (value: 1) or off (value: 0) the nebular emission modeling.
dust_law – Choice for the dust attenuation law. Options are: 0 for Charlot & Fall (2000) and 1 for Calzetti et al. (2000).
sfh_form – Choice for the parametric SFH model. Options are: 0 for exponentially declining or tau model, 1 for delayed tau model, 2 for log normal model, 3 for Gaussian form, and 4 for double power-law model.
add_agn – Choice for turning on (value: 1) or off (value: 0) the AGN dusty torus modeling.
add_igm_absorption – Choice for turning on (value: 1) or off (value: 0) the IGM absorption modeling.
igm_type – Choice for the IGM absorption model. Options are: 0 for Madau (1995) and 1 for Inoue+(2014).
smooth_velocity – (default: True) The same parameter as in FSPS. Switch to perform smoothing in velocity space (if True) or wavelength space.
sigma_smooth – (default: 0.0) The same parameter as in FSPS. If smooth_velocity is True, this gives the velocity dispersion in km/s. Otherwise, it gives the width of the gaussian wavelength smoothing in Angstroms. These widths are in terms of sigma (standard deviation), not FWHM.
smooth_lsf – (default: False) The same parameter as in FSPS. Switch to apply smoothing of the SSPs by a wavelength dependent line spread function. Only takes effect if smooth_velocity is True.
lsf_wave – Wavelength grids for the input line spread function. This must be in the units of Angstroms, and sorted ascending.
lsf_sigma – The dispersion of the Gaussian line spread function at the wavelengths given by lsf_wave, in km/s. This array must have the same length as lsf_wave. If value is 0, no smoothing will be applied at that wavelength.
cosmo – Choices for the cosmology. Options are: (1)’flat_LCDM’ or 0, (2)’WMAP5’ or 1, (3)’WMAP7’ or 2, (4)’WMAP9’ or 3, (5)’Planck13’ or 4, (6)’Planck15’ or 5. These options are similar to the choices available in the Astropy Cosmology package.
H0 – The Hubble constant at z=0. Only relevant when cosmo=’flat_LCDM’ is chosen.
Om0 – The Omega matter at z=0.0. Only relevant when cosmo=’flat_LCDM’ is chosen.
param_val – Dictionary of the input values of the parameters. Should folllow the structure given in the default set. Summary of the parameters are tabulated in Table 1 of Abdurro’uf et al. (2021).

Returns photo_SED:

Output model photometric SED. It consists of photo_SED[‘wave’], which is the central wavelengths of the photometric filters, and photo_SED[‘flux’], which is the photometric fluxes.

piXedfit.piXedfit_model.generate_modelSED_spec(sp=None, imf_type=1, duste_switch=1, add_neb_emission=1, dust_law=1, sfh_form=4, add_agn=0, add_igm_absorption=0, igm_type=0, smooth_velocity=True, sigma_smooth=0.0, smooth_lsf=False, lsf_wave=None, lsf_sigma=None, cosmo='flat_LCDM', H0=70.0, Om0=0.3, params_val={'dust1': 0.5, 'dust2': 0.5, 'dust_index': -0.7, 'gas_logu': -2.0, 'gas_logz': None, 'log_age': 1.0, 'log_alpha': 0.1, 'log_beta': 0.1, 'log_fagn': -3.0, 'log_gamma': -2.0, 'log_mass': 0.0, 'log_qpah': 0.54, 'log_t0': 0.4, 'log_tau': 0.4, 'log_tauagn': 1.0, 'log_umin': 0.0, 'logzsol': 0.0, 'z': 0.001}, add_neb_continuum=1)

Function for generating a model spectrum given some parameters.

Parameters:

sp – (optional, default: None) Initialization of FSPS, such as sp=fsps.StellarPopulation(). This is intended for rapid generation of model spectra from FSPS. However, this input is optional. If sp=None, FSPS will be called everytime this function is called.
imf_type – Choice for the IMF. Choices are: 0 for Salpeter(1955), 1 for Chabrier(2003), and 2 for Kroupa(2001).
duste_switch – Choice for switching on (value: 1) or off (value: 0) the dust emission modeling.
add_neb_emission – Choice for switching on (value: 1) or off (value: 0) the nebular emission modeling.
dust_law – Choice for the dust attenuation law. Options are: 0 for Charlot & Fall (2000) and 1 for Calzetti et al. (2000).
sfh_form – Choice for the parametric SFH model. Options are: 0 for exponentially declining or tau model, 1 for delayed tau model, 2 for log normal model, 3 for Gaussian form, and 4 for double power-law model.
add_agn – Choice for turning on (value: 1) or off (value: 0) the AGN dusty torus modeling.
add_igm_absorption – Choice for turning on (value: 1) or off (value: 0) the IGM absorption modeling.
igm_type – Choice for the IGM absorption model. Options are: 0 for Madau (1995) and 1 for Inoue+(2014).
smooth_velocity – (default: True) The same parameter as in FSPS. Switch to perform smoothing in velocity space (if True) or wavelength space.
sigma_smooth – (default: 0.0) The same parameter as in FSPS. If smooth_velocity is True, this gives the velocity dispersion in km/s. Otherwise, it gives the width of the gaussian wavelength smoothing in Angstroms. These widths are in terms of sigma (standard deviation), not FWHM.
smooth_lsf – (default: False) The same parameter as in FSPS. Switch to apply smoothing of the SSPs by a wavelength dependent line spread function. Only takes effect if smooth_velocity is True.
lsf_wave – Wavelength grids for the input line spread function. This must be in the units of Angstroms, and sorted ascending.
lsf_sigma – The dispersion of the Gaussian line spread function at the wavelengths given by lsf_wave, in km/s. This array must have the same length as lsf_wave. If value is 0, no smoothing will be applied at that wavelength.
cosmo –
Choices for the cosmology. Options are: (1)’flat_LCDM’ or 0, (2)’WMAP5’ or 1, (3)’WMAP7’ or 2, (4)’WMAP9’ or 3, (5)’Planck13’ or 4, (6)’Planck15’ or 5. These options are similar to the choices available in the Astropy Cosmology package.
H0 – The Hubble constant at z=0. Only relevant when cosmo=’flat_LCDM’ is chosen.
Om0 – The Omega matter at z=0.0. Only relevant when cosmo=’flat_LCDM’ is chosen.
param_val –
Dictionary of the input values of the parameters. Should folllow the structure given in the default set. Summary of the parameters are tabulated in Table 1 of Abdurro’uf et al. (2021).

Returns spec_SED:

Array containing output model spectrum. It consists of spec_SED[‘wave’], which is the wavelengths grids, and spec_SED[‘flux’], which is the fluxes or the spectrum.

piXedfit.piXedfit_model.save_models_photo(filters, gal_z, imf_type=1, sfh_form=4, dust_law=1, add_igm_absorption=0, igm_type=0, duste_switch=0, add_neb_emission=1, add_agn=0, nmodels=100000, nproc=10, smooth_velocity=True, sigma_smooth=0.0, smooth_lsf=False, lsf_wave=None, lsf_sigma=None, cosmo='flat_LCDM', H0=70.0, Om0=0.3, params_range={'dust1': [0.0, 4.0], 'dust2': [0.0, 4.0], 'dust_index': [-2.2, 0.4], 'gas_logu': [-4.0, -1.0], 'gas_logz': None, 'log_age': [-2.0, 1.14], 'log_alpha': [-2.0, 2.0], 'log_beta': [-2.0, 2.0], 'log_fagn': [-5.0, 0.48], 'log_gamma': [-4.0, 0.0], 'log_qpah': [-3.0, 1.0], 'log_t0': [-1.0, 1.14], 'log_tau': [-1.0, 1.5], 'log_tauagn': [0.7, 2.18], 'log_umin': [-1.0, 1.39], 'logzsol': [-2.0, 0.2]}, name_out=None)

Function for generating a set of photometric model SEDs and store them into a FITS file. The values of the parameters are randomly generated and for each parameter, the random values are uniformly distributed.

Parameters:

filters –
List of photometric filters. The list of filters recognized by piXedfit can be accessed using piXedfit.utils.filtering.list_filters(). Please see this page for information on managing filters that include listing available filters, adding, and removing filters.
gal_z – Galaxy’s redshift.
imf_type – Choice for the IMF. Choices are: 0 for Salpeter(1955), 1 for Chabrier(2003), and 2 for Kroupa(2001).
sfh_form – Choice for the parametric SFH model. Options are: 0 for exponentially declining or tau model, 1 for delayed tau model, 2 for log normal model, 3 for Gaussian form, and 4 for double power-law model.
dust_law – Choice for the dust attenuation law. Options are: 0 for Charlot & Fall (2000) and 1 for Calzetti et al. (2000).
add_igm_absorption – Choice for turning on (value: 1) or off (value: 0) the IGM absorption modeling.
igm_type – Choice for the IGM absorption model. Options are: 0 for Madau (1995) and 1 for Inoue+(2014).
duste_switch – Choice for switching on (value: 1) or off (value: 0) the dust emission modeling.
add_neb_emission – Choice for switching on (value: 1) or off (value: 0) the nebular emission modeling.
add_agn – Choice for turning on (value: 1) or off (value: 0) the AGN dusty torus modeling.
nmodels – Number of model SEDs to be generated.
params_range –
Ranges of parameters in a dictionary format. Summary of the parameters are tabulated in Table 1 of Abdurro’uf et al. (2021).
nproc – Number of cores to be used in the calculations.
smooth_velocity – (default: True) The same parameter as in FSPS. Switch to perform smoothing in velocity space (if True) or wavelength space.
sigma_smooth – (default: 0.0) The same parameter as in FSPS. If smooth_velocity is True, this gives the velocity dispersion in km/s. Otherwise, it gives the width of the gaussian wavelength smoothing in Angstroms. These widths are in terms of sigma (standard deviation), not FWHM.
smooth_lsf – (default: False) The same parameter as in FSPS. Switch to apply smoothing of the SSPs by a wavelength dependent line spread function. Only takes effect if smooth_velocity is True.
lsf_wave – Wavelength grids for the input line spread function. This must be in the units of Angstroms, and sorted ascending.
lsf_sigma – The dispersion of the Gaussian line spread function at the wavelengths given by lsf_wave, in km/s. This array must have the same length as lsf_wave. If value is 0, no smoothing will be applied at that wavelength.
cosmo –
Choices for the cosmology. Options are: (1)’flat_LCDM’ or 0, (2)’WMAP5’ or 1, (3)’WMAP7’ or 2, (4)’WMAP9’ or 3, (5)’Planck13’ or 4, (6)’Planck15’ or 5. These options are similar to the choices available in the Astropy Cosmology package.
H0 – The Hubble constant at z=0. Only relevant when cosmo=’flat_LCDM’ is chosen.
Om0 – The Omega matter at z=0.0. Only relevant when cosmo=’flat_LCDM’ is chosen.

Returns name_out_fits:

Desired name for the output FITS file. if None, a default name will be used.

piXedfit.piXedfit_model.save_models_rest_spec(imf_type=1, sfh_form=4, dust_law=1, duste_switch=0, add_neb_emission=1, add_agn=0, nmodels=100000, nproc=5, smooth_velocity=True, sigma_smooth=0.0, smooth_lsf=False, lsf_wave=None, lsf_sigma=None, params_range={'dust1': [0.0, 4.0], 'dust2': [0.0, 4.0], 'dust_index': [-2.2, 0.4], 'gas_logu': [-4.0, -1.0], 'gas_logz': None, 'log_age': [-2.0, 1.14], 'log_alpha': [-2.0, 2.0], 'log_beta': [-2.0, 2.0], 'log_fagn': [-5.0, 0.48], 'log_gamma': [-4.0, 0.0], 'log_qpah': [-3.0, 1.0], 'log_t0': [-1.0, 1.14], 'log_tau': [-1.0, 1.5], 'log_tauagn': [0.7, 2.18], 'log_umin': [-1.0, 1.39], 'logzsol': [-2.0, 0.2]}, name_out=None)

Function for generating a set of model spectra at rest-frame. The values of the parameters are randomly generated and for each parameter, the random values are uniformly distributed.

Parameters:

imf_type – Choice for the IMF. Choices are: 0 for Salpeter(1955), 1 for Chabrier(2003), and 2 for Kroupa(2001).
sfh_form – Choice for the parametric SFH model. Options are: 0 for exponentially declining or tau model, 1 for delayed tau model, 2 for log normal model, 3 for Gaussian form, and 4 for double power-law model.
dust_law – Choice for the dust attenuation law. Options are: 0 for Charlot & Fall (2000) and 1 for Calzetti et al. (2000).
duste_switch – Choice for switching on (value: 1) or off (value: 0) the dust emission modeling.
add_neb_emission – Choice for switching on (value: 1) or off (value: 0) the nebular emission modeling.
add_agn – Choice for turning on (value: 1) or off (value: 0) the AGN dusty torus modeling.
nmodels – Number of model SEDs to be generated.
params_range –
Ranges of parameters in a dictionary format. Summary of the parameters are tabulated in Table 1 of Abdurro’uf et al. (2021).
nproc – Number of cores to be used in the calculations.
smooth_velocity – (default: True) The same parameter as in FSPS. Switch to perform smoothing in velocity space (if True) or wavelength space.
sigma_smooth – (default: 0.0) The same parameter as in FSPS. If smooth_velocity is True, this gives the velocity dispersion in km/s. Otherwise, it gives the width of the gaussian wavelength smoothing in Angstroms. These widths are in terms of sigma (standard deviation), not FWHM.
smooth_lsf – (default: False) The same parameter as in FSPS. Switch to apply smoothing of the SSPs by a wavelength dependent line spread function. Only takes effect if smooth_velocity is True.
lsf_wave – Wavelength grids for the input line spread function. This must be in the units of Angstroms, and sorted ascending.
lsf_sigma – The dispersion of the Gaussian line spread function at the wavelengths given by lsf_wave, in km/s. This array must have the same length as lsf_wave. If value is 0, no smoothing will be applied at that wavelength.

Returns name_out:

Name for the output HDF5 file.