arXiv subjects

Francesco Lorenzo Villante

Publications and source records attributed to Francesco Lorenzo Villante.

7 recordsLinked to original sources

arXiv2025

Search for Diffuse Galactic Neutrinos with the Full ANTARES Telescope Dataset

The diffuse emission of gamma-rays and neutrinos, produced by interactions of cosmic rays with interstellar matter in the Milky Way, provides valuable insights into cosmic ray propagation and Galactic processes. Emission models incorporating different assumptions about cosmic ray diffusion, source distribution, and target gas density are tested using data from neutrino telescopes. In this study, the final all-flavor neutrino dataset, collected over 15 years (2007--2022) by the ANTARES neutrino telescope, is analyzed. A maximum likelihood ratio method built to handle templates of Galactic emission models is employed to evaluate the compatibility of these models with the observed spatial and energy distributions of neutrino events. The results do not yield stringent constraints on the tested models and upper limits on the diffuse neutrino flux are derived, which are compatible with the results obtained by other experiments.

astro-ph.HE↗

arXiv2025

LHAASO protons versus LHAASO diffuse gamma-rays: a consistency check

We perform the first direct consistency check between the recently measured proton spectrum at the knee by Large High Altitude Air Shower Observatory (LHAASO) and the collaboration's own high-precision mapping of Galactic diffuse gamma-ray emission. By modeling the hadronic gamma-ray production using the updated cosmic-ray spectra, gas templates and cross-section models, we show that the predicted gamma-ray flux robustly overshoots the LHAASO data in both inner and lateral Galactic regions. This persistent mismatch in both normalization and spectral shape challenges conventional scenarios linking the local cosmic-ray sea to Galactic gamma-ray emission, and calls for a revision of current cosmic ray models in the TeV-PeV sky.

astro-ph.HE↗

arXiv2023

The contribution of Galactic TeV pulsar wind nebulae to Fermi-LAT diffuse emission

The large-scale diffuse $γ-$ray flux observed by Fermi-LAT in the 1-100 GeV energy range, parameterized as $\propto E^{-Γ}$, has a spectral index $Γ$ that depends on the distance from the Galactic center. This feature, if attributed to the diffuse emission produced by cosmic rays (CR) interactions with the interstellar gas, can be interpreted as the evidence of a progressive CR spectral hardening towards the Galactic center. This interpretation challenges the paradigm of uniform cosmic rays diffusion throughout the Galaxy. We report on the implications of TeV Pulsar Wind Nebulae observed by the HESS Galactic Plane Survey in the 1-100 TeV energy range for the interpretation of Fermi-LAT data. We argue that a relevant fraction of this population cannot be resolved by Fermi-LAT in the GeV domain providing a relevant contribution to the large-scale diffuse emission, viz. $\sim 30\%$ of the total diffuse $γ$-ray emission in the inner Galaxy. This additional component naturally accounts for a large part of the spectral index variation observed by Fermi-LAT, weakening the evidence of CR spectral hardening in the inner Galaxy.

astro-ph.HE↗

arXiv2020

The TeV gamma-ray luminosity of the Milky-Way and the contribution of H.E.S.S. unresolved sources to VHE diffuse emission

H.E.S.S. has recently completed a systematic survey of the Galactic plane in the TeV energy domain. We analyze the flux, latitude and longitude distributions of $γ-$ray sources observed by H.E.S.S. in order to infer the properties of Galactic TeV source population. We show that the total Milky-Way luminosity in the 1-100 TeV energy range is $L_{\rm MW} = 1.7^{+0.5}_{-0.4}\times 10^{37} {\rm ergs}\,{\rm sec}^{-1}$. Evaluating the cumulative flux expected at Earth by the considered population, we show that H.E.S.S. unresolved sources provide a relevant contribution to the diffuse Galactic emission. Finally, in the hypothesis that the majority of bright sources detected by H.E.S.S. are powered by pulsar activity, like e.g. Pulsar Wind Nebulae or TeV halos, we estimate the main properties of the pulsar population.

astro-ph.HE↗

arXiv2011

Non-Standard Neutrino Propagation and Pion Decay

Motivated by the findings of the OPERA experiment, we discuss the hypothesis that neutrino propagation does not obey Einstein special relativity. Under a minimal set of modifications of the standard model Lagrangian, we consider the implications of non standard neutrino propagation on the description of neutrino interactions and, specifically, on the pion decay processes. We show that all the different dispersion relations which have been proposed so far to explain OPERA results, imply huge departures from the standard expectations. The decay channel $π^+ \to e^+ ν_{\rm e}$ becomes significantly larger than in the standard scenario, and may even dominate over $π^+ \to μ^+ ν_{\rm μ}$. Moreover, the spectral distribution of neutrinos produced in the decay processes and the probability that a pion decays in flight in neutrinos show large deviations from the standard results.

hep-ph↗

arXiv2009

On the Goals of Neutrino Astronomy

What do we mean by neutrino astronomy? Which information is it able to provide us and which is its potential? To address these questions, we discuss three among the most relevant sources of neutrinos: the Sun; the core collapse supernovae; the supernova remnants. For each of these astronomical objects, we describe the state of the art, we present the expectations and we outline the most actual problems from the point of view of neutrino astronomy.

astro-ph.HE↗

arXiv2008

Formation of quark phases in compact stars and SN explosion

We describe possible scenarios of quark deconfinement in compact stars and we analyze their astrophysical implications. The quark deconfinement process can proceed rapidly, as a strong deflagration, releasing a huge amount of energy in a short time and generating an extra neutrino burst. If energy is transferred efficiently to the surface, like e.g. in the presence of convective instabilities, this burst could contribute to revitalize a partially failed SN explosion. We discuss how the neutrino observations from SN1987A would fit in this scenario. Finally, we focus on the fate of massive and rapidly rotating progenitors, discussing possible time separations between the moment of the core collapse and the moment of quark deconfinement. This mechanism can be at the basis of the interpretation of gamma ray bursts in which lines associated with heavy elements are present in the spectrum.

astro-ph↗