Super-Kamiokande (SK) is a 50-kton water Cherenkov detector, instrumented with ∼13k photomultipliers and running since 1996. It is sensitive to neutrinos with energies ranging from 4.5 MeV to several TeV. A new framework has been developed for the follow-up of gravitational wave (GW) alerts issues by the LIGO-Virgo collaboration (LVC). Neutrinos are searched for, using a 1000-second time...
The Surface Detector (SD) of the Pierre Auger Observatory is used to search for ultra-high-energy (UHE) neutrinos with energies beyond 0.1 EeV of all flavours. They induce extensive air showers (EASs) that are efficiently detected and well distinguishable from those produced by UHE cosmic rays. This, along with the large aperture of the SD, leads to a UHE neutrino sensitivity competitive to...
The last decade of experimental data has provided many insights on the
most extreme phenomena in the Universe where gravity and particle
physics come together. A multi-messenger approach, combining data from
complementary experiments and exploiting the intimate connection
between ultra-high-energy cosmic rays, photons and neutrinos, is
needed to shed light on the still open crucial...
The ANTARES neutrino telescope and its next-generation successor, KM3NeT, located in the abyss of the Mediterranean Sea, have been designed to study neutrinos from a variety of sources over a wide range of energies and baselines. One of the primary goals of the experiments is to determine the Earth matter effects stemming from the energy and zenith angle dependence of the atmospheric neutrinos...
Addressing the origin of the observed astrophysical neutrino flux is of paramount importance nowadays, since the sources generating such neutrinos still remain a mystery. Among the likely astrophysical sources of detectable high-energy neutrinos (e.g. blazars, supernova remnants etc.), also Gamma-Ray Bursts (GRBs) play a fundamental role, since they are among the few astrophysical sources...
In a recent time-integrated investigation of a catalog of 110 gamma-ray emitters, IceCube observed a cumulative neutrino excess in the flux produced during 10 years. Such an excess, incompatible with the background at the level of $3.3\sigma$, was mainly due to the starburst galaxy NCG 1068 and the BL Lacs TXS 0506+056, PKS 1424+240 and GB6 J1542+6129. Here we present the results of a...
Blazars are the most extreme subclass of active galactic nuclei with relativistic jets emerging from a super-massive black hole and forming a small angle with respect to our line of sight. Blazars are also known to be flaring sources: they exhibit large flux variations over a wide range in frequency and on multiple timescales, ranging from a few minutes to several months. Blazar flares have...
Dark matter's existence (DM) has been well-established by repeated experiments over many length scales. Even though DM is expected to make up 85% of the current matter content of the Universe, its nature remains unknown. One broad class of corpuscular DM motivated by Standard Model (SM) extensions is weakly interacting massive particles (WIMPs). WIMPs generically have a non-zero cross-section...
In this controbution a combined measurement of the energy spectra of atmospheric electron and muon neutrinos in the energy range between 100 GeV and 50 TeV with the ANTARES neutrino telescope is presented. The analysis uses 3012 days of detector livetime in the period 2007–2017, and selects 1016 neutrinos interacting in (or close to) the instrumented volume of the detector, yielding...
The discovery of an astrophysical flux of high-energy neutrinos with IceCube is a milestone in the field of multi-messenger astronomy. Traditional time-integrated searches for point-like neutrino sources have so far been unsuccessful because of large backgrounds and weak neutrino signals. IceCube’s capability of observing the sky with full duty cycle enables us to search for transient neutrino...
Astrophysical neutrinos at hundreds of TeV are expected to originate in
hadronic interactions, but their sources are still unknown. The chance of
identifying the emitting objects can be improved by a rapid electromagnetic
follow-up of neutrino events. Here, the MAGIC telescopes play a relevant role in
identifying very high energy (>100 GeV) γ-ray counterparts. This is achieved...
The measurement of an astrophysical flux of high-energy neutrinos by IceCube is an important step towards finding the long-sought sources of cosmic rays. Nevertheless, the long exposure neutrino sky map shows no significant indication of point sources so far. This may point to a large population of faint, steady sources or flaring objects as origins of this flux. The most compelling evidence...
The gamma-ray blazar TXS 0506+056 was discovered in very high energy (>100 GeV) gamma-rays by the MAGIC telescopes in 2017 in a coincidence with a high energy neutrino event IC-170922A. Subsequent multiwavelength (MWL) observations and theoretical modeling suggest that this source could be a cosmic ray and neutrino emitter. So far, this is the most significant association between a high-energy...
In view of the IceCube's 6-year high-energy starting events (HESE) sample,
we revisit the possibility that the updated data may be better explained
by a combination of neutrino fluxes from dark matter decay and an
isotropic astrophysical power-law than purely by the latter. We find
that the combined two-component flux qualitatively improves the fit
to the observed data over a purely...
The IceCube Neutrino Observatory detects neutrinos by collecting the Cherenkov light created by their interaction products within one cubic km of ice. Neutrinos of a particular flavor produce corresponding charged leptons in charged current (CC) interactions. Each type of lepton can create a distinct light emission pattern in the detector. The hardest to observe is the pattern of the tau...
Blazars whose low-energy spectral component peaks above ~0.4 keV are thought to be efficient particle accelerators and are known as extreme blazars. They are particularly interesting for high-energy astrophysics, as they may be the counterparts of very high-energy gamma-ray sources and high-energy astrophysical neutrinos. 3HSP J095507.9+355101 is the first extreme blazar to be possibly...
Acceleration of cosmic rays in hot and magnetized coronae of active galactic nuclei will lead to the production of high-energy neutrinos and soft gamma rays. These optically thick environments, hidden in gamma-rays, are the promising environment for producing the flux of high-energy cosmic neutrinos at medium energies. In this talk, we present the high-energy cosmic neutrinos flux from the...
I discuss the potential of current and future liquid scintillator neutrino detectors of $\mathcal O (10)$ kt mass to localize a presupernova neutrino signal in the sky. In the hours preceding the core collapse of a nearby star (at distance $D$ less than 1 kpc), tens to hundreds of inverse beta decay events will be recorded, and their reconstructed topology in the detector can be used to...
