  NGC5128 galaxy is a giant elliptical galaxy located in the Centaurus group of
galaxies at 3.8 Mpc. We aim to study the star formation history (SFH) of two
different fields of the galaxy. The northeastern field (Field 1) is located at
a distance of 18.8 kpc, while the southern field (Field 2) is at 9.9 kpc. We
use a photometric method that is based on identifying long period variable
(LPV) stars and asymptotic giant branch (AGB) stars, as they are strong tracers
of star formation and galaxy evolution due to their luminosity and variability;
395 LPVs in Field 1 and 671 LPVs in Field 2 have been identified. These two
fields present similar SFHs, although the SF rate of Field 2 is more enhanced.
We find that the galaxy has three major star formation episodes t $\sim$ 800
Myr ago, t $\sim$ 3.2 Gyr ago, and t $\sim$ 10 Gyr ago, where t is look-back
time. The rate of star formation at $\sim$ 800 Myr ago agrees with previous
studies suggesting that the galaxy experienced a merger around that time.
Furthermore, NGC5128 has experienced a lower star formation rate in its recent
history which could have been driven by jet-induction star formation and
multiple outbursts of AGN activity in this galaxy, as well as a minor merger
around 400 Myr ago.
