  We have conducted a near-infrared monitoring campaign at the UK InfraRed
Telescope (UKIRT), of the Local Group spiral galaxy M 33 (Triangulum). A new
method has been developed by us to use pulsating giant stars to reconstruct the
star formation history of galaxies over cosmological time as well as using them
to map the dust production across their host galaxies. In first Instance the
central square kiloparsec of M33 was monitored and long period variable stars
(LPVs) were identified. We give evidence of two epochs of a star formation rate
enhanced by a factor of a few. These stars are also important dust factories,
we measure their dust production rates from a combination of our data with
Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was
expanded to cover a much larger part of M33 including spiral arms. Here we
present our methodology and describe results for the central square kiloparsec
of M33 (Javadi et al. 2011 a,b,c, 2013) and disc of M33 (Javadi et al. 2015,
2016, 2017, and in preparation).

Astrophysics of Galaxies;Solar and Stellar Astrophysics