|Microlensing is the amplification
of the light of a background star due to the transit on the line of
sight of a massive object, which acts as a gravitational lens. The
lens can be another star or a brown dwarf. The light curve of the
background star has a typical bell shape, with a duration of a few
days. Since microlensing events are very rare, millions of source
stars must be monitored every night in order to detect them.
Microlensing can be used to
search for extrasolar planets. In fact, if the lens is a
star accompanied by a planet, the light curve of the source contains
an anomaly like a secondary peak or a dip. We are members of the
Microlensing Science Investigation Team for the mission
WFIRST by NASA. Our group is part of the
MiNDSTEp collaboration, observing from the
Danish telescope at ESO, La Silla (Chile) and from
Salerno University Observatory. We are
members of the ROME-REA
collaboration for source characterization.
We have also
developed an advanced code for automatic real-time modeling of
anomalous microlensing events (RTModel).
This is based on the publicly available software
VBBinaryLensing for the calculation
of microlensing light curves.
Extrasolar planets can also be
found by their transits on the disk of the
mother-star. Salerno University Observatory
is part of the KELT-follow-up
network and the TESS-follow-up
group for candidate transit validation (see
paper on the discovery of KELT-9b).
We are also included
in the Gaia follow-up
Side projects include quasar microlensing, variables in
globular clusters, elliptic binaries.
Gravitational lensing by black holes
leads to the spectacular formation of infinite sequences of images
very close to the shadow cast by the black hole in the sky. The
direct observation of this shadow has been recently achieved by the
Event Horizon Telescope. The black hole in the center of our Galaxy
provides the best candidate for new observations that are opening a new era in gravitational physics.
|Early universe cosmology
investigates the first instants of our universe. General Relativity
is not sufficient to describe the hot quantum universe close to the
big bang. String theory and other quantum gravity theories suggest
the possibility that the big bang was actually not the beginning of
time, but just a transition from a previous pre-big bang collapsing
universe to our observed expanding universe.
The Baryon Asymmetry problem
refers to the observed asymmetry in the Universe between baryonic
and antibaryonic matter. Since the Big Bang should have produced
equal amounts of matter and antimatter, it is then expected that
some still unkonw mechanism must have acted differently for matter
and antimatter during the Universe evolution. This mechanism cannot
be explaind within the standard model of particle physics and
cosmology, and in fact, modern theories aimed at solving the problem
of the baryon asymmetry are based on physics beyond these models.