  Full spectrum fitting is a powerful tool for estimating the stellar
populations of galaxies, but the fitting results are often significantly
influenced by internal dust attenuation. For understanding how the choice of
the internal dust correction method affects the detailed stellar populations
estimated from the full spectrum fitting, we analyze the Sydney-Australian
Astronomical Observatory Multi-object Integral field spectrograph (SAMI) galaxy
survey data using the Penalized PiXel-Fitting (PPXF) package. Three choices are
compared: (Choice-1) using the PPXF reddening option, (Choice-2) using the
multiplicative Legendre polynomial, and (Choice-3) using none of them (no dust
correction). In any case, the total mean stellar populations show reasonable
mass-age and mass-metallicity relations (MTR and MZR), although the
correlations appear to be strongest for Choice-1 (MTR) and Choice-2 (MZR). When
we compare the age-divided mean stellar populations, the MZR of young (< 10^9.5
yr ~ 3.2 Gyr) stellar components in Choice-2 is consistent with the gas-phase
MZR, whereas those in the other two choices hardly are. On the other hand, the
MTR of old (>= 10^9.5 yr) stellar components in Choice-1 seems to be more
reasonable than that in Choice-2, because the old stellar components in
low-mass galaxies tend to be relatively younger than those in massive galaxies.
Based on the results, we provide empirical guidelines for choosing the optimal
options for dust correction.
