| dc.description.abstract | The search for exoplanets is one of the most exciting challenges. From the
first exoplanets discovered around the pulsar PSR B1 257+12 back in 1992 until
today there are over 5200 exoplanets discovered. And the number will continue
to rise in the coming years with the advent of the latest generation telescopes.
There are various techniques for finding exoplanets such as transit, radial
velocity, pulsar timing, direct imaging etc. But among these, gravitational
microlensing is one of the most fascinating. Gravitational microlensing is
a particular technique to detect exoplanets otherwise unavailable with other
techniques such as transits or radial velocity. We have a microlensing event
when the light from a distant source is deflected by a lens passing through
the source and the observer. The result, in the simplest case, is a bell-shaped
peak in the light curve. Planets can be detected studying the anomalies in the
lightcurve (additional peaks or dips, longer distortions, etc.). But microlensing
is not important only for exoplanets. The fact that with this technique it is
possible to reach distances of the order of the galactic center allows us to
discover objects ranging from the disk to the bulge allowing us to have a much
more complete overview of the study of the stellar populations of our galaxy.
And in particular with the study of binary systems we can detect faint objects
that are impossible to reveal with other techniques, such as brown dwarfs,
mysterious objects of which little is known yet and which are presumed to
populate our galaxy in great abundance. Microlensing is undoubtedly the
best method to discover these objects, since having extremely low luminosities
they are difficult to see with telescopes except when they play the role of
lens. Moreover, in some cases the orbital motions of the system can also be
detected, allowing us to study their dynamics in more detail. The typology of
microlensing events is enormous and in this thesis we will analyze some of the
cases that can occur. In the first part we focus on the fundamental concepts of
microlensing theory for the exoplanets search. The second part is dedicated to
the modeling of microlensing events, which is based on the VBBinaryLensing
code. In the third part we analyze some microlensing events, each with certain
characteristics, to highlight how vast the case history of these events is. Finally
there will be the conclusions where the results achieved and future prospects
are discussed. [edited by Author] | it_IT |
