Module skytools.color_correction

Functions

def mbb_color_correction(beta, T, frequency_in_GHz, transmission, central_frequency_GHz, iras_norm=False)

Expand source code

def mbb_color_correction(beta, T, frequency_in_GHz, transmission, central_frequency_GHz, iras_norm=False):
    """Compute the color-correction factor for a modified blackbody spectrum.

    Parameters
    ----------
    beta : float
        Spectral emissivity index.
    T : float
        Blackbody temperature in kelvin.
    frequency_in_GHz : array-like
        Frequency grid in GHz across the instrument bandpass.
    transmission : array-like
        Bandpass transmission sampled on ``frequency_in_GHz``.
    central_frequency_GHz : float
        Reference (central) frequency in GHz.
    iras_norm : bool, optional
        If ``True``, apply IRAS-style normalization.

    Returns
    -------
    float
        Multiplicative color-correction factor converting band-averaged
        response to the monochromatic response at ``central_frequency_GHz``.
    """
    norm_transmission = transmission / np.trapezoid(transmission, frequency_in_GHz * con.giga)
     
    sed_in_band = el.modified_blackbody(frequency_in_GHz, beta, T,)
    band_sed = np.trapezoid(sed_in_band * norm_transmission, frequency_in_GHz * con.giga)
    
    central_sed = el.modified_blackbody(central_frequency_GHz, beta, T)
    
    iras_norm_factor = 1.
    if iras_norm:
        iras_norm_factor = np.trapezoid((central_frequency_GHz/frequency_in_GHz)*norm_transmission, frequency_in_GHz*con.giga)
    
    return iras_norm_factor * central_sed / band_sed

Compute the color-correction factor for a modified blackbody spectrum.

Parameters

beta : float

Spectral emissivity index.

T : float

Blackbody temperature in kelvin.

frequency_in_GHz : array-like

Frequency grid in GHz across the instrument bandpass.

transmission : array-like

Bandpass transmission sampled on frequency_in_GHz.

central_frequency_GHz : float

Reference (central) frequency in GHz.

iras_norm : bool, optional

If True, apply IRAS-style normalization.

Returns

float

Multiplicative color-correction factor converting band-averaged response to the monochromatic response at central_frequency_GHz.

def powerlaw_color_correction(beta, frequency_in_GHz, transmission, central_frequency_GHz, iras_norm=False)

Expand source code

def powerlaw_color_correction(beta, frequency_in_GHz, transmission, central_frequency_GHz, iras_norm=False):
    """Compute the color-correction factor for a power-law spectrum.

    Parameters
    ----------
    beta : float
        Spectral index of the power law.
    frequency_in_GHz : array-like
        Frequency grid in GHz across the instrument bandpass.
    transmission : array-like
        Bandpass transmission sampled on ``frequency_in_GHz``.
    central_frequency_GHz : float
        Reference (central) frequency in GHz.
    iras_norm : bool, optional
        If ``True``, apply IRAS-style normalization.

    Returns
    -------
    float
        Multiplicative color-correction factor converting band-averaged
        response to the monochromatic response at ``central_frequency_GHz``.
    """
    norm_transmission = transmission / np.trapezoid(transmission, frequency_in_GHz * con.giga)
     
    sed_in_band = (frequency_in_GHz * con.giga)**beta
    band_sed = np.trapezoid(sed_in_band * norm_transmission, frequency_in_GHz * con.giga)
    
    central_sed = (central_frequency_GHz * con.giga)**beta
    
    iras_norm_factor = 1.
    if iras_norm:
        iras_norm_factor = np.trapezoid((central_frequency_GHz/frequency_in_GHz)*norm_transmission, frequency_in_GHz*con.giga)
    
    return iras_norm_factor * central_sed / band_sed

Compute the color-correction factor for a power-law spectrum.

Parameters

beta : float

Spectral index of the power law.

frequency_in_GHz : array-like

Frequency grid in GHz across the instrument bandpass.

transmission : array-like

Bandpass transmission sampled on frequency_in_GHz.

central_frequency_GHz : float

Reference (central) frequency in GHz.

iras_norm : bool, optional

If True, apply IRAS-style normalization.

Returns

float

Multiplicative color-correction factor converting band-averaged response to the monochromatic response at central_frequency_GHz.