GW170817-GRB170817A provided the first direct evidence that at least a fraction of binary neutron star mergers (BNSs) are progenitors of short Gamma-Ray Bursts (sGRBs). More BNS signals are expected from the upcoming observation runs of the gravitational wave (GW) interferometers. In these systems, each messenger carries unique information about the astrophysical processes at the source. The...
Multimessenger astronomy is a new way of exploring the Universe by combining data from different cosmic messengers such as gravitational waves and electromagnetic radiation. One of the best astrophysical targets for performing multimessenger analysis is Binary Neutron Star (BNS) coalescences, which produce both gravitational waves and detectable multiwavelength electromagnetic emissions. The...
The Pierre Auger Observatory, the largest ultra-high energy cosmic ray detector ever constructed, has an unprecedented sensitivity to neutral primaries above 10^17 eV.
After almost 20 years of data taking, stringent limits to the diffuse flux of photons and neutrinos have been derived, excluding many exotic models for the origin of UHE cosmic particles. Furthermore, targeted searches and...
The joint detection of a short GRB and gravitational waves had long been a goal by astronomers that was finally realized with GRB/GW 170817A. The GRB emission was much less luminous than expected though, with a peak luminosity more than two orders of magnitude lower than any other short GRB known. This implies that there is a population of low-luminosity short GRBs and greatly motivates more...
Core collapse supernovae are among the most energetic explosions in the modern Universe and one of the long-standing riddles of stellar astrophysics. The detection of a gravitational wave signal coming from a core collapse supernovae would be extremely interesting, due to the fact that it would give us the chance to probe the core dynamics of a dying massive star and, eventually, enlighten the...
Some of the most important open questions in particle physics are: What is dark matter? What is the origin of the domination of matter over antimatter in the Universe? How are neutrino masses generated? I will discuss how gravitational wave experiments can help us probe theories proposing solutions to the above puzzles. I will concentrate on a class of models in which baryon and lepton number...
I will show that a new gravitational wave signature is expected in extensions of the Standard Model with extra gauge symmetries broken at vastly different energy scales. The spectrum contains a characteristic double-peak structure consisting of a sharp peak from domain walls and a smooth bump from a first order phase transition in the early Universe. I will provide an example of such a model,...
I will discuss new types of gravitational wave signatures which arise in extensions of the Standard Model with two U(1) gauge symmetries broken at high energy scales, focusing on the case when those symmetries are gauged baryon and lepton number. Such theories accommodate dark matter, leptogenesis, and the seesaw mechanism for neutrinos. The gravitational wave spectrum consists of...
Understanding the gravitational wave signals from cosmological sources, such as first order phase transitions and cosmic strings, is currently a popular and active area of research. Such sources can also produce energetic particles, such as gamma rays, neutrinos, and dark matter, thereby producing distinct particle astrophysics signals. This talk will provide a broad discussion of the...
Recent associations of high-energy neutrinos with active galactic nuclei (AGN) have revived the interest in leptohadronic models of radiation from astrophysical sources. The rapid increase in multi-messenger observations requires fast numerical models that may be applied to large source samples. In this contribution, we introduce LeHaMoC, a newly developed code for solving (using an implicit...
In 2013, the IceCube collaboration announced the detection of diffuse high-energy astrophysical neutrino flux. The origin of these particles is still unknown as there is still no identification of a source at the 5-sigma level. To answer this question, IceCube releases realtime alerts triggering follow-up observations in multiple wavelengths looking for electromagnetic counterparts to...
Multimessenger observation of neutrino sources is a key for identifying the origin of astrophysical neutrinos, and it led to the identification of the blazar TXS 0506+056 as the first candidate in 2017. When the IceCube observatory detects likey astrophysical neutrino events, alerts are sent to the other telescopes to trigger follow up observations. A newly proposed algorithm is optimized to...
In addition to its implications for astrophysics, the hunt for neutrinos from Gamma-Ray Bursts (GRBs) could also be significant in quantum-gravity research, since they are excellent probes of the microscopic fabric of spacetime. Over the last few years one of the most studied candidate effects of quantum gravity has been in-vacuo dispersion, a phenomenon suggesting an energy-dependent speed...
The challenges inherent to time-domain multi-messenger astronomy require strategic actions to perform suited, optimized follow-up observations efficiently. Poorly localized events require dedicated tiling and/or targeted follow-up campaigns so that the source location can be efficiently covered, increasing the chances to detect the multi-wavelength counterpart. We have developed the python...
KM3NeT is a multi-site and multi-purpose neutrino telescope under construction in the depth of the Mediterranean Sea. It consists of two Cherenkov telescopes, ARCA (in Italy) and ORCA (in France), both of which are currently taking data with partial detector configurations. Among the primary scientific goals of KM3NeT is the observation of cosmic neutrinos and the identification of their...
HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging (<10 arcsec FWHM) and broad spectral coverage (0.1-150 keV) with an effective area far superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. HEX-P is ideally suited to address important problems in the...
TXS 0506+056, source of the extreme energy neutrino event, IceCube-170922A, has an interesting environment to study the lepto-hadronic emissions. The Fermi-LAT detector reported high energy (HE) γ-ray flare between 100 MeV and 100 GeV starting from 15 September 2017 from this source. Several follow-ups to trace the very high energy (VHE) gamma-ray counterparts around the IceCube-170922A...
Recently IceCube observed TeV neutrino emission from the nearby Seyfert type-II Galaxy, NGC 1068, which suggests that AGN could potentially be one type of source of the diffuse high-energy astrophysical neutrino flux. Disk-corona models, which predict neutrino emission using the observed keV X-rays luminosity from the Seyfert galaxies, are employed to search for similar sources. In this...
Recent observations have revealed that Tidal Disruption Events (TDEs), caused by the gravitational disruption of a massive star close to a supermassive black hole (SMBH), can produce intense flares of radiation with the duration of months to years. Notably, three TDE candidates (AT2019dsg, AT2019fdr, and AT2019aalc) are likely associated with IceCube astrophysical neutrinos. In this talk, I...
Recent radio observations of tidal disruption events (TDEs) show that some TDEs exhibit late time emission, which may be due to delayed jet launch from the central engine. The multi-messenger observations of several TDEs (AT2019dsg, AT2019fdr, and AT2019aalc) by IceCube and optical telescopes also provide evidence for the possibility of late time engine activity. In this work, we address this...
Since their discovery, cosmic rays (CRs) remain among the most mysterious phenomena of modern Physics. The dominant sources, as well as the exact acceleration mechanisms, remain unknown. The CRs up to the ``knee’’ have traditionally been considered to originate entirely in the shock waves of supernova remnants (SNRs), however, due to the lack of a “smoking-gun” TeV counterpart in many cases,...
The well-studied graviton-to-photon conversion process provides an intriguing method to observe early universe gravitational wave sources. However, these effects are suppressed when considering magnetic fields present in the early universe, due to the presence of the Standard Model plasma. In contrast, a dark magnetic field would induce a graviton-to-dark photon conversion process, but not be...
Gamma-ray bursts (GRBs) have late-time emission components lasting 100-1000 seconds, such as extended emission of short GRBs and X-ray flares of long GRBs. These components could be explained by the internal dissipation of the jets produced by prolonged central engine activity, and could be influenced by the materials around the jet. The prompt jet interacts with the progenitor star or the...
