def ab_flux_in_ergs_s_cm2_A(wave) :
    """
    Args:

     wave: 1D numpy array (Angstrom)

    Returns:

      ab flux in units of ergs/s/cm2/A
    """

    #import astropy.units
    #default_wavelength_unit = astropy.units.Angstrom
    #default_flux_unit = astropy.units.erg / astropy.units.cm**2 / astropy.units.s / default_wavelength_unit
    #_ab_constant = 3631. * astropy.units.Jansky * astropy.constants.c).to(default_flux_unit * default_wavelength_unit**2)

    _ab_constant = 0.10885464 # Angstrom erg / (cm2 s)
    return _ab_constant / wave**2