From monitoring survey of variable red giant stars to the evolution of the galaxy: Andromeda VII

We have observed the Andromeda VII dwarf galaxy (And VII) using optical multi-epochs with the Isaac Newton Telescope (INT), in order to identify AGB stars. Among AGB stars, we concentrated on long-period variable stars (LPVs) with the largest amplitudes at optical wavelengths. Because these stars are cool at the end of their evolution and their luminosities reach maxima, their birth mass is directly related to luminosity by employing theoretical evolutionary tracks. Since the periods of LPVs are months to years, we have taken t$10$ epochs from And VII during the period $2015-2017$, spaced by a month or more in the $i$- and $V$-bands, plus one epoch in the $I$-band, to find these variable stars. As a result, a catalogue of $10,000$ stars and $48$ LPVs was identified within two half-light radii of And VII. The $i-$band amplitude of variability for our LPV stars ranged from $0.2$--$1.6$ mag. We used the luminosity distribution of those stars to reconstruct their star formation history, employing a method that we have applied in the cases of other Local Group galaxies. By using as well the Spitzer catalogues at mid-IR wavelengths, we constructed a detailed map of the mass feedback into the interstellar medium (ISM).