Explore the vast range of titles available.

The discovery of high-energy astrophysical neutrinos and the first hints of coincident electromagnetic and neutrino emissions opened new opportunities in multi-messenger astronomy. Owing to their high power, transient sources are expected to supply a significant fraction of the observed energetic astroparticles, through enhanced particle acceleration and interactions. Here, we review theoretical expectations of neutrino emission from transient astrophysical sources and the current and upcoming experimental landscape, highlighting the most promising channels for discovery and specifying their detectability.The discovery of high-energy astrophysical neutrinos and the first hints of coincident electromagnetic and neutrino emissions opened new opportunities in multi-messenger astronomy. We review theoretical expectations of neutrino emission from transient astrophysical sources and the current and upcoming experimental landscape.

The Giant Radio Array for Neutrino Detection (GRAND) is a planned large-scale observatory of ultra-high-energy (UHE) cosmic particles, with energies exceeding 10 8 GeV. Its goal is to solve the long-standing mystery of the origin of UHE cosmic rays. To do this, GRAND will detect an unprecedented number of UHE cosmic rays and search for the undiscovered UHE neutrinos and gamma rays associated to them with unmatched sensitivity. GRAND will use large arrays of antennas to detect the radio emission coming from extensive air showers initiated by UHE particles in the atmosphere. Its design is modular: 20 separate, independent sub-arrays, each of 10000 radio antennas deployed over 10000 km 2 . A staged construction plan will validate key detection techniques while achieving important science goals early. Here we present the science goals, detection strategy, preliminary design, performance goals, and construction plans for GRAND.

Psychotraumatic disorders, particularly post-traumatic stress disorder (PTSD), have been a major public health issue for many years. However, many patients remain resistant to treatment, with significant levels of residual symptoms, a high dropout rate, and poor functional prognosis despite a reduction in psychotraumatic symptoms. The physical impact of trauma might influence treatment response. We have developed an integrative method for patients suffering from post-traumatic stress disorder (PTSD). In this study, we report the cases of 16 successive patients with PTSD treated with adjunct psychomotor trauma exposure. The data were collected retrospectively from the clinical records of subjects treated with adjunct psychomotor exposure therapy at the Hauts-de-France Regional Center for Psychotrauma. Severity of psychotrauma was reported using PCL-5 before and one month after treatment. A decrease in PCL-5 score was seen in all participants between baseline (45.6 ± 11.6) at the end of treatment (16.6 ± 10.1) (  < .001). Adjunct psychomotor exposure therapy is a promising tool for the treatment of PTSD. Future high-quality randomised controlled trials are necessary.

High-energy neutrino flares are interesting prospective counterparts to photon flares, as their detection would guarantee the presence of accelerated hadrons within a source, provide precious information about cosmic-ray acceleration and interactions, and thus impact the subsequent modeling of non-thermal emissions in explosive transients. In these sources, photomeson production can be efficient, producing a large amount of secondary particles, such as charged pions and muons, that decay and produce high-energy neutrinos. Before their decay, secondary particles can experience energy losses and acceleration, which can impact high-energy neutrino spectra and thus affect their detectability. In this work, we focus on the impact of secondary acceleration. We consider a one zone model, characterized mainly by a variability timescale \\(t_{\\rm var}\\), a luminosity \\(L_{\\rm bol}\\), a bulk Lorentz factor \\(\\Gamma\\). The mean magnetic field \\(B\\) is deduced from these parameters. The photon field is modeled by a broken power-law. This generic model allows to evaluate systematically the maximum energy of high-energy neutrinos in the parameter space of explosive transients, and shows that it could be strongly affected by secondary acceleration for a large number of source categories. In order to determine the impact of secondary acceleration on the high-energy neutrino spectrum and in particular on its peak energy and flux, we complement these estimates by several case studies. We show that secondary acceleration can increase the maximum neutrino flux, and produce a secondary peak at the maximum energy in the case of efficient acceleration. Secondary acceleration could therefore enhance the detectability of very-high-energy neutrinos, that will be the target of next generation neutrino detectors such as KM3NeT, IceCube-Gen2, POEMMA or GRAND.

The possibility of slow diffusion regions as the origin for extended TeV emission halos around some pulsars (such as PSR J0633+1746 and PSR B0656+14) challenges the standard scaling of the electron diffusion coefficient in the interstellar medium. Self-generated turbulence by electron-positron pairs streaming out of the pulsar wind nebula was proposed as a possible mechanism to produce the enhanced turbulence required to explain the morphology and brightness of these TeV halos. We perform fully kinetic 1D3V particle-in-cell simulations of this instability, considering the case where streaming electrons and positrons have the same density. This implies purely resonant instability as the beam does not carry any current. We compare the linear phase of the instability with analytical theory and find very reasonable agreement. The non-linear phase of the instability is also studied, which reveals that the intensity of saturated waves is consistent with a momentum exchange criterion between a decelerating beam and growing magnetic waves. With the adopted parameters, the instability-driven wavemodes cover both the Alfvénic (fluid) and kinetic scales. The spectrum of the produced waves is non-symmetric, with left-handed circular polarisation waves being strongly damped when entering the ion-cyclotron branch, while right-handed waves are suppressed at smaller wavelength when entering the Whistler branch. The low-wavenumber part of the spectrum remains symmetric when in the Alfvénic branch. As a result, positrons behave dynamically differently compared to electrons. We also observed a second harmonic plasma emission in the wave spectrum. An MHD-PIC approach is warranted to probe hotter beams and investigate the Alfvén branch physics. This work confirms that the self-confinement scenario develops essentially according to analytical expectations [...](abridged)

The recent discovery of high-energy astrophysical neutrinos and first hints of coincident electromagnetic and neutrino emission herald the beginning of the era of multi-messenger astronomy. Due to their high power, transient sources are expected to supply a significant fraction of the observed energetic astroparticles, through enhanced particle acceleration and interactions. Here, we review theoretical expectations of neutrino emission from transient astrophysical sources and the current and upcoming experimental landscape, highlighting the most promising channels for discovery and specifying their detectability.

The origin of the gamma-ray halo around pulsars is associated with the reduced diffusivity of energetic particles responsible for gamma-ray emission with respect to the mean-free path they adopt in the interstellar medium. A possible explanation for this behaviour is that the energetic particles released from the pulsarwind termination shock themselves trigger the turbulence necessary to explain this reduced diffusivity. In order to test the ability of the electron-positron beam to trigger an efficient streaming instability we are in the process of conducting a series of b simulations using both the PIC-MHD technique to follow the evolution of both the electron-positron beam and the thermal background plasma and determine whether the beam can trigger the necessary instabilities. We find that the passage of the electron-positron beam through the thermal plasma triggers streaming instabilities that lead to local amplification of the magnetic field.

The new generation of powerful instruments is reaching sensitivities and temporal resolutions that will allow multi-messenger astronomy of explosive transient phenomena, with high-energy neutrinos as a central figure. We derive general criteria for the detectability of neutrinos from powerful transient sources, for given instrument sensitivities. In practice, we provide the minimal photon flux necessary for neutrino detection based on two main observables, the bolometric luminosity and the time variability of the emission. This limit can be compared to the observations in specified wavelengths in order to target the most promising sources for follow-ups. Our criteria can also help discriminating false associations of neutrino events with a flaring source. We find that relativistic transient sources such as High- and Low-Luminosity GRBs, Blazar flares, Tidal Disruption Events and magnetar flares could be observed with IceCube, as they have a good chance to occur within a detectable distance. Among non-relativistic transient sources, only luminous supernovae appear as promising candidates. We caution that our criterion should not be directly applied to low-luminosity GRBs and Type Ibc supernovae, as these objects could have hosted a choked GRB, leading to neutrino emission without a relevant counterpart radiation. We treat a set of concrete examples and show that several transients, some of which are being monitored by IceCube, are far from meeting the criterion for detectability (e.g., Crab flares or Swift J1644+57).

During the Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) mission, we planned Target of Opportunity (ToO) operations to follow up on possible sources of \\(\\gtrsim 10 \\, {\\rm PeV}\\) neutrinos. The original plan before flight was to point the onboard Cherenkov Telescope (CT) to catch the source's path on the sky just below Earth's horizon. By using the Earth as a tau-neutrino to tau-lepton converter, the CT would then be able to look for optical extensive air shower signals induced by tau-lepton decays in the atmosphere. The CT had a field of view of \\(6.4^\\circ\\) vertical \\(\\times\\) \\(12.8^\\circ\\) horizontal. Possible neutrino source candidates include gamma ray bursts, tidal disruption events and other bursting or flaring sources. In addition, follow-ups of binary neutron star mergers would have been possible after the start of the O4 observation run from LIGO-Virgo-KAGRA. The resulting exposure is modeled using the NuSpaceSim framework in ToO mode. With the launch of the EUSO-SPB2 payload on the 13th May 2023, this summarizes the ToO program status and preliminary data, as available.