The Universe is home to many energetic
phenomena that create populations of charged particles out of
thermal equilibrium. Those particles then can propagate away
from their sources as cosmic rays, and deposit energy
throughout their parent galaxies. Thus, high-energy processes
influence the interstellar medium, the process of star
formation, and galaxy evolution. Charged particles are
challenging to study because they are continuously deflected
by magnetic fields and, by the time we catch them near the
Earth, cannot be tracked back to their sources. However,
energetic particles interact with matter and electromagnetic
fields, creating neutral products (radio emission, sub-mm
lines, gamma rays, neutrinos) that point to their creation
site.
My specialty consists in the study of high-energy
astrophysical phenomena and cosmic particles using gamma rays.
I use gamma-ray data from a number of instruments, along with
multiwavelength/multimessenger observations, to study how
particles are accelerated, propagate, and interact with the
interstellar medium on all scales, from individual energetic
objects (e.g., supernova remnants, pulsars), to regions of
massive-star formation, and up to the scales of whole
galaxies. The diffuse gamma-ray glow produced by cosmic rays
as they propagate through galaxies not only gives us
information about these particles, but it is also a tracer of
the interstellar medium complementary to observations carried
out at many other wavelengths, and produces a
foreground/background that we need to understand in order to
study individual objects, as well as diffuse gamma rays
produced by other types of processes, e.g., the extragalactic
gamma-ray background and potential dark-matter signals.
Lately I have also being exploring how gamma-ray observations
can help us to understand the mysterious asymmetry between
matter and antimatter in the Universe. The laws of physics
known to date suggest that the Big Bang should have created
equal amounts of matter and antimatter, leading to mutual
annihilation. Yet, the reality is starkly different, with
observations pointing to matter being overwhelmingly prevalent
around the Solar System and the Milky Way. Furthermore,
data dismissed the notion of a perfect balance between matter
and antimatter across the entire Universe. The origin of the
matter-antimatter asymmetry remains an unsolved enigma and
theories beyond the Standard Model of Particle Physics have
been proposed to explain it. The dominant paradigm today is
that from a very early phase the Universe has been composed
almost exclusively of matter. Yet, we have high-quality
astrophysical and cosmological observations that hold the
potential to quantify the presence of antimatter in the
Universe far beyond what has been done to date.
Observational facilities are key to making
progress in our understanding of the Universe. I am currently
mainly involved in two projects.
