  We study the ages of a large sample (1,802) of nearly face-on disk low
surface brightness galaxies (LSBGs) by using the evolutionary population
synthesis (EPS) model PEGASE with exponential decreasing star formation rate to
fit their multiwavelength spectral energy distributions (SEDs) from
far-ultraviolet (FUV) to near-infrared (NIR). The derived ages of LSBGs are 1-5
Gyr for most of the sample no matter the constant or varying dust extinction is
adopted, which are similar to most of the previous studies on smaller samples.
This means that these LSBGs formed their majority of stars quite recently.
However, a small part of the sample (~2-3%) have larger ages as 5-8 Gyr,
meaning their major star forming process may occur earlier. At the same time, a
large sample (5,886) of high surface brightness galaxies (HSBGs) are selected
and studied in the same method for comparisons. The derived ages are 1-5 Gyr
for most of the sample (97%) as well. These may mean that probably these LSBGs
have no much different star formation history from their HSBGs counterparts.
But we should notice that the HSBGs are about 0.2 Gyr younger generally, which
could mean that the HSBGs may have more recent star forming activities than the
LSBGs.
