A new era in gamma-ray astronomy is upon us, thanks to a combination of instruments covering an unprecedented energy range from GeV to PeV. Space-based missions such as Fermi, ground-based Imaging Air Cherenkov Telescopes (IACTs), and extensive air shower arrays now provide a unified view of the most energetic sky. This multi-instrument approach has revealed over 300 sources, all of which are...
In this talk I will present the general characteristics of stochastic gravitational wave signals from the early universe and discuss some interesting sources, with a particular focus on first order phase transitions.
While black holes are typically known as the remnants of stellar collapse, some may have formed in the early universe—these are known as primordial black holes (PBHs). Unlike most dark matter candidates, primordial black holes do not require the introduction of new fundamental physics, making them a compelling possibility. In this talk, I will outline the current observational constraints on...
W51 is one of the most massive and active star-forming complexes in the Milky Way. Multiple experiments, including Fermi-LAT, MAGIC, HESS, HAWC, and most recently LHAASO, have detected gamma-ray emission associated with this region. The complex hosts two major star-forming regions, W51A and W51B, and the middle-aged supernova remnant (SNR) W51C. The latter has been associated with the...
We analyze data from 142 gravitational wave (GW) sources in the fourth LVK Gravitational-Wave Transient Catalog (GWTC-4.0) to estimate the Hubble constant $H_0$ jointly with the population properties of merging compact binaries. We measure the luminosity distance and redshifted masses of GW sources, and combine this with redshift information obtained by leveraging features in the binary mass...
The recent detection of a multi-PeV neutrino event by KM3NeT/ARCA opens a new window into the origin of high-energy neutrinos and ultra-high-energy cosmic rays. We revise the possibility of a cosmogenic origin of this neutrino by analysing the constraints induced by cascaded photons onto the isotropic gamma-ray background measured by the Fermi-LAT collaboration.
We consider two scenarios: the...
The Gamma-Ray and Antimatter Survey (GRAMS) project is a next-generation MeV-scale gamma-ray and antimatter experiment. The detector consists of a liquid argon time projection chamber (LArTPC), the largest of its kind in an astrophysics experiment. Surrounding the LArTPC are plastic scintillator bars for charged particle time-of-flight (TOF) measurement. The LArTPC is the main detector and...
Primordial black holes (PBHs) may constitute part of all the Dark Matter, and as they evaporate they should emit an all particle spectrum, including neutrinos. The recently suggested theoretical framework of "memory burden" would allow the survival until today of PBHs with masses low enough to evaporate into particles of energy at the PeV and above.
In this talk we explore the scenario in...
Crystal Eye is a new concept of space-based all sky monitor for the observation of 10 keV $-$ 30 MeV photons exploiting novel detection techniques. It foresees enhanced localization capability and detection power of the astrophysical short-duration outburst phenomena in an unprecedented energy range with respect to other concurrent instruments. The instrument uses the advantage of new detector...
In 10 years since the first direct observation of a gravitational wave (GW), GW astronomy has made giant leaps, going from detecting loud binary black hole (BBH) coalescences, to binary neutron star (BNS) and black hole -- neutron star (BHNS) binary events, all the way to large-volume population analyses. Yet the vast majority of events are too faint to be directly detected with coherent...
PandaX-4T is a multi-tonne-scale dark matter direct searching experiment, utilizing 3.7 tonne liquid xenon as target material in sensitive volume. The experiment is located at China Jinping Underground Laboratory, with overburden of 2400 meter water equivalent. In 2021, the PandaX-4T experiment has released its first data and obtained various search result at the time. In this talk, I will...
On February 13 2023, at 01:16:46 UTC, the KM3NeT/ARCA neutrino telescope detected the $\sim 220$ PeV neutrino candidate KM3-230213A. Remarkably, the Yangbajing muon telescope in Tibet recorded a simultaneous burst of muons, showing a 5.7σ excess from a compatible direction. The burst exhibits a statistically significant exponential time profile, with a decay constant of τ = 7.0 ± 1.5 minutes,...
The nature and formation mechanisms of subsolar-mass (SSM) black hole binaries remain an open question in astrophysics, as such objects fall outside the predictions of standard stellar evolution. The LIGO-Virgo-KAGRA (LVK) collaboration has conducted searches for compact binary mergers involving at least one subsolar-mass component, using data from recent observing runs. This search targets...
LHAASO reported 43 ultra-high-energy sources that are either proton or electron PeVatrons (Cao+24), and multi-wavelength data are crucial for determining particle species and the CR energy density of the source. In this project, we study the LHAASO J1912+1014u (and HESS J1912+101) region using Fermi-LAT and FUGIN CO data to investigate the “proton PeVatron” scenario. We analyzed 15 years of...
Monitoring the sky in the MeV energy range is crucial for understanding the nature of explosive events in the Universe. Since the Universe is transparent to MeV gamma rays, we can observe the most distant transient phenomena, such as gamma-ray bursts (GRBs). In 2017, there was the first joint observation of gravitational waves (GW) events from binary neutron stars and a GRB that initiated a...
The supernova remnant (SNR) W44, one of the first sources firmly established as a hadronic accelerator in the GeV regime, has been observed for over 200 hours with the H.E.S.S. telescope array. We present the results of a deep analysis of this dataset, revealing new insights into the gamma-ray emission from W44 and its interaction with the surrounding interstellar medium. In particular, we...
The identification of gamma rays in coincidence with high-energy neutrinos plays a fundamental role in multi-messenger astronomy, as such observations are essential for constraining source localization, determining source classes, and investigating emission mechanisms. The present study evaluates the prospects of Cherenkov Telescope Array Observatory (CTAO) for detecting very-high-energy (VHE)...
Highly dense and isospin asymmetric matter is partly out of the reach of nuclear laboratories on Earth. Our theoretical understanding of strong and nuclear forces at high density and relatively low temperatures is also limited such that the equation of state and properties of dense matter remain a mystery. However, this particular type of matter comprises the deepest shells of the highly...
The PICO Collaboration uses bubble chamber technology for direct-detection searches of Weakly-Interacting Massive Particles (WIMP). Filled with superheated C$_3$F$_8$, the thermodynamic threshold of PICO detectors can be set such that the detectors are optimised for dark matter detection while being insensitive to gammas from electron recoils. The presence of fluorine atoms in the C$_3$F$_8$...
The detection of Ultra-High-Energy (UHE) neutrinos is key for the understanding of cosmic-ray acceleration mechanisms and the identification of their astrophysical sources. The Surface Detector of the Pierre Auger Observatory, comprising 1660 water-Cherenkov particle detectors deployed over an area of 3000 km$^2$, has operated continuously for over two decades, providing some of the most...
The Cherenkov Telescope Array Observatory (CTAO) will be the next-generation ground-based gamma-ray observatory, with two arrays in both hemispheres offering full-sky coverage and improved sensitivity over a broad energy range, from 20 GeV to 300 TeV. The standard pointing mode, where all telescopes are aligned to observe the same sky region, provides excellent performance in terms of...
High-energy neutrino emission from black hole accretion flows is a promising probe of extreme plasma environments and cosmic-ray acceleration in active galactic nuclei (AGNs). While many previous studies have relied on simplified single-zone models, the influence of large-scale plasma inhomogeneity and turbulence remains poorly understood. In this study, we perform the first global simulations...
DEAP-3600 is an experiment performing direct dark matter searches since 2016. The detector is undergoing a third fill in order to achieve its goal sensitivity of 1e-46 cm2 for the WIMP-nucleon interaction cross section. This science case is achievable thanks to its location 2 km underground at SNOLAB, a thorough RnD to minimize its background and the background discrimination capabilities...
Supernova remnants are discussed as the main sources for Galactic cosmic-rays. However, observational and theoretical developments in the last decade have lead to the idea that only supernova explosions in very dense circumstellar media are able to accelerate particles to the relevant energies and only in the first decades after the explosion.
The medium around massive stars tends to be highly...
Imaging Air Cherenkov Telescopes and Ground Based Arrays are the major contributors to Gamma
Ray astronomy at ground level. The Southern Wide-Field Gamma-ray Observatory (SWGO) will be a
water Cherenkov Array located in the Atacama Desert in Chile that will monitor the VHE and UHE sky.
The Naples group has proposed a multi-photomultiplier (multiPMT) detector for SWGO, based on
KM3NeT and...
We develop a first-principles formalism, based on the transport equation in the line-of-sight approximation, to link the expected number of muons at neutrino telescopes to the flux of neutrinos at the Earth's surface. We compute the distribution of muons inside Earth, arising from the up-scattering of neutrinos close to the detector, as well as from the decay of taus produced farther away....
The Cygnus region is one of the richest and most complex areas on the Galactic plane, known for its intense star formation and the presence of numerous very-high-energy gamma-ray sources. Among these sources, VER J2019+368 ranks as one of the brightest, exhibiting a hard spectrum and complex morphology that suggests the presence of powerful particle accelerators. First discovered by MILAGRO...
The DarkSide-20k experiment is a next-generation multi-ton dark matter detector currently being built at the INFN Gran Sasso National Laboratory (LNGS) and designed for zero instrumental background direct detection of Weakly Interacting Massive Particle Dark Matter. The DarkSide-20k detector is a dual-phase time projection chamber (TPC) deploying 50 tonnes of underground low-radioactivity...
The solar plasma is a natural source of gravitational waves at high frequencies, a spectral range that is attracting increasing interest due to its potential to reveal new physical phenomena. Motivated by this, in this talk, I will present the first comprenhensive calculation of the gravitational-wave power spectrum emitted by the Sun. This includes both microscopic processes—such as...
Accurately modeling neutrino flavor oscillations in global simulations of core-collapse supernovae or neutron star mergers remains a major challenge, albeit a potentially crucial one for making reliable predictions. Indeed, it is now widely recognized that flavor instabilities—in which classically computed neutrino distributions are dramatically altered when including quantum effects—are...
The project Probing Extreme PeVatron Sources (PEPS) aims at measuring the most energetic gamma rays from our Galaxy in the energy range between 10¹⁵eV and 5x10¹⁶ eV, opening a new energy window for multimessenger astroparticle physics. PEPS will consist of an array of 10 km² placed in the southern hemisphere, at the location of the Pierre Auger Observatory. It will be built in two phases, with...
Relativistic jets interact with multiple obstacles as they cross their host galaxies, before interacting with the interstellar or intergalactic medium at hotspots, in powerful sources, or plumes, in low power ones. We assume the possibility that a supernova explosion happens within the jet, and this may have a strong impact not only on the jet dynamics during the evolution of the supernova...
LUX-ZEPLIN (LZ) is a dark matter experiment located at the Sanford Underground Research Facility in South Dakota, USA, employing a 7 tonne active volume of liquid xenon in a dual-phase time projection chamber. Its deep underground location and an extensive material assay program enable LZ to have achieved an observed background level of 6.3±0.5×10$^{−5}$ events/keVee/kg/day in the WIMP search...
Wide-field surveys like Euclid mark a new era of extragalactic stellar stream studies, with exciting applications in measuring baryon and dark matter distributions, and connecting galaxies to their cosmological context.
I present results from a pilot study combining Euclid imaging with Zooniverse classifications to detect and analyze stellar streams of extragalactic systems. We use projected...
MAGIC is a system of two 17-m Cherenkov telescopes located at the Observatorio Roque de los Muchachos on the Canary Island of La Palma, Spain. The telescopes have been in operations for two decades and during that time, the observation program evolved, adjusting to the new discoveries and ideas in astrophysics. Every year the telescopes observe a mixture of Galactic and Extragalactic targets....
In 2019, the first Large-Sized Telescope (LST-1) of the Cherenkov Telescope Array Observatory (CTAO) for the Northern Hemisphere array site started observations next to the two MAGIC telescopes at the Roque de los Muchachos Observatory in La Palma, Canary Islands. Since 2020 an increasing number of joint observations involving all three telescopes have been carried out. Joint MAGIC+LST-1...
DarkSide-20k is a next-generation, direct dark matter search experiment
located at LNGS (Italy), aiming for a background-free exposure of 200 tonne-years,
i.e < 0.1 neutron WIMP-like event. The core of the detector is a dual-phase
Time Projection Chamber (TPC) filled with 50 tonnes of low radioactivity
liquid argon. The entire TPC wall is surrounded by a 15 cm of pure
polymethylmethacrylate...
I will illustrate the development of new methods, and their results, to determine the dark matter distribution in field galaxies.
Machine learning algorithms trained within the synthetic environment of numerical cosmological simulations -such as the IllustrisTNG- offer the potential to validate and test the reliability of the Dark Matter distribution in such controlled environment, before...
MUTE (MUon inTensity codE) is a Python program that performs calculations for cosmic-ray muons underground and underwater. It combines two state-of-the-art programs, DAEMONFLUX and PROPOSAL, to provide comprehensive calculations for muon intensities, total muon fluxes, energy and angular spectra, and mean muon energies at the surface, in deep underground laboratories — under both flat...
Blazars are a sub-class of Active Galactic Nuclei (AGN) and constitute the most populous class of sources in the extragalactic very-high-energy (VHE) sky. They are characterized by stochastic variability that spans from radio to VHE gamma rays (E > 100 GeV), whose origins are still being debated. Detecting more VHE blazars at different energies and distances is crucial for a better...
Gravitational Waves (GW) from compact binary coalescence like Black Holes or Neutron Stars behave like standard sirens and can be used to perform cosmological inference, in particular on the Hubble constant. In order to build the Hubble diagram, however, an independent measurement of the redshift is required, which is not always available. Here we propose a novel methodology which does not...
The Global Argon Dark Matter Collaboration is currently developing its flagship detector,
DarkSide-20k (DS-20k), a multi-tonne-scale experiment designed for the direct detection of the
weakly interacting massive particles using a double-phase Liquid Argon Time Projection
Chamber (LAr TPC) with 20.2 tonnes of fiducial mass. The shift from its predecessor,
DarkSide-50, with 46.4 kg of active...
The NA62 experiment at CERN is designed to measure the highly-suppressed decay $K^{+} \to \pi^{+}\nu\bar{\nu}$ and has collected a large sample of $K^+$ decays in flight during Run 1 (2016-2018) and Run 2 (since 2021). Searches for the decay $K^{+}\rightarrow\pi^{+}X$ using data from 2016-2022, set upper limits on the branching ratio at the $10^{-11}$ level, constraining a broad range of New...
The ASTRI Mini-Array is an international project led by the Italian National Institute for Astrophysics (INAF) to develop, build, and operate nine Cherenkov telescopes at the Observatorio del Teide, on the island of Tenerife. The array is planned to operate for at least 8 years, performing deep observations of Galactic and extragalactic sources in the energy range from 1 to 200 TeV. These...
Flat Spectrum Radio Quasars (FSRQs) are rarely detected at very-high-energy (VHE, E > 100 GeV) gamma rays due to their distance, soft spectra, and strong absorption from the Extragalactic Background Light (EBL). In December 2023, the Large-Sized Telescope prototype (LST-1) of the Cherenkov Telescope Array Observatory (CTAO) and the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC)...
Darkside-20k is a global direct dark matter search experiment situated underground at LNGS (Italy), designed to reach a total exposure of 200 tonne-years, nearly free from instrumental backgrounds. The core of the detector is a dual-phase Time Projection Chamber (TPC) filled with 50 tonnes of low-radioactivity liquid argon. The entire TPC wall is surrounded by polymethylmethacrylate (PMMA),...
The discovery of radio galaxies as very high-energy (VHE, E > 100 GeV) gamma-ray emitters is one of the most significant legacy results from the current generation of Cherenkov telescopes. Contrary to the majority of TeV-detected active galactic nuclei, radio galaxies have misaligned jets (θ >10°). Thus, they offer unique views across multiple wavelengths to explore particle acceleration...
Charged ultra-high-energy cosmic rays are thought to be produced by astrophysical
processes such as shock acceleration. Their subsequent interactions also contribute to
the production of secondary gamma rays and neutrinos. However, physics beyond the Standard Model
at very high energy scales could also contribute to the fluxes of both charged and neutral
ultra-high-energy particles. Examples...
We consider the possible production of a new MeV-scale fermion at the COHERENT, LZ and XENONnT experiments, and the future DUNE detector. The new fermion, belonging to a dark sector, can be produced through the up-scattering process of neutrinos off the nuclei and the electrons of the detector material, via the exchange of a light mediator. We explore the possibility of generalized...
The recent observation of Coherent Elastic Neutrino–Nucleus Scattering (CE$\nu$NS) from solar $\rm ^8B$ neutrinos by dark matter direct detection experiments marks the first identification of the so-called “neutrino floor”. Far from being a mere background for dark matter searches, this signal opens a novel window to probe light new physics.
In this talk, I will present new constraints on...
The Relic Axion Detector Exploratory Setup (RADES) collaboration works on the development of new techniques for axion searches. Axions are hypothetical pesudoscalar pseudoNambu-Goldstone bosons that appear as part of the solution to the the strong CP problem of QCD. At the same time they could also be the answer to one of the most puzzling questions on cosmology, the Dark Matter problem.
In...
Recent Fermi-LAT observations have revealed GeV gamma-ray emission from several radio-quiet Seyfert galaxies, challenging the traditional view that powerful jets are required to produce high-energy gamma rays in active galactic nuclei (AGNs). One such object, GRS 1734-292, is a nearby Seyfert galaxy with empirically weak starburst and jet activity, yet it exhibits a significant gamma-ray...
Despite extensive astrophysical evidence supporting its existence, the nature of dark matter remains one of the most compelling open questions in modern physics. One promising approach for probing its properties is indirect detection, which involves searching for its signals from regions of the universe where dark matter is expected to be concentrated. Such searches often target astrophysical...
The Southern Wide-field Gamma-ray Observatory (SWGO) will be a next generation ground array experiment probing the Southern sky in search of gamma-ray sources from the Galactic plane. The collaboration has chosen as primary site Pampa la Bola in the Atacama Astronomical Park (Chile) at 4770 m above the sea level. SWGO will detect the secondary particles through Water Cherenkov Detectors (WCD)....
BabyIAXO is the initial stage of the International Axion Observatory (IAXO), designed to search for solar axions and axion-like particles (ALPs) with unprecedented sensitivity. It incorporates a straight, large-aperture dipole magnet, precision X-ray optics, and ultra-low background detectors, enabling both early-stage data acquisition and validation of the experimental approach for the...
Understanding the nature of dark matter remains one of the central challenges in modern physics. A promising strategy to probe its properties is indirect detection which searches for excesses of Standard Model particles produced by dark matter annihilation or decay in astrophysical objects. The Galactic Center is a particularly compelling target due to its high dark matter density and relative...
ALPACA is a new air shower array experiment under construction in Bolivia. Surface array with 401 scintillating counters covers an area of 82,800 m^2. Together with the underground water-Cherenkov muon detectors covering 3600 m^2 established by the Tibet ASgamma group, a high CR/gamma separation power is achieved. ALPACA realizes a wide-field gamma-ray survey at 10-1000TeV energy range for the...
To explore the largely uncharted dark matter mass range between 10 TeV and several PeV, the Dark100 experiment aims to deploy an array of six Imaging Air Cherenkov Telescopes (IACTs) optimized for detecting gamma rays at these extreme energies. These telescopes, originally developed for the Panoramic Search for Extraterrestrial Intelligence (PANOSETI), provide a scalable and cost-effective...
Blazars are among the most powerful objects in the Universe and are prime candidates for producing ultra-high-energy cosmic rays and astrophysical neutrinos. Yet, despite decades of observations across the full electromagnetic spectrum, their emission mechanisms remain elusive. In today’s multi-messenger era, combining data from different cosmic messengers with advanced modeling tools is key...
The DAMIC-M (DArk MAtter in CCDs at a Modane) collaboration aims to directly detect dark matter in Charge-Coupled-Devices (CCDs). Utilizing fully depleted CCDs and a floating-gate (“skipper”) amplifier, the detector — operated deep underground at the Laboratoire Souterrain de Modane (LSM) — can resolve eV-scale interactions of Hidden Sector Dark Matter. The Low Background Chamber (LBC), the...
In this talk, I will review recent developments in high-energy extragalactic astrophysics, particularly concerning high-energy particles, including gamma-rays and neutrinos, in supermassive black holes, blazars, gamma-ray bursts, tidal disruption events, and binary neutron star mergers. We have not found a significant correlation between the arrival directions of ultra-high-energy cosmic rays...
In recent years, remarkable progresses have been made with the direct detection of cosmic rays in space, reshaping our understanding of the origin, acceleration, and propagation of cosmic rays. This talk will summarize the latest experimental findings, including the matter and antimatter in cosmic rays, the primary and secondary components of cosmic nuclei, isotopic energy spectra, and the...
Accurate modeling of cosmic ray spectra and atmospheric lepton fluxes is fundamental to interpreting astrophysical neutrino observations, understanding neutrino oscillations, constraining hadronic interaction models, and enabling applications from new physics searches to muon tomography. This talk presents recent advances in modeling atmospheric muon and neutrino fluxes at multi-GeV to TeV...
The observation of gravitational waves (GWs) by the LIGO-Virgo-KAGRA (LVK) Collaboration has opened an entirely new window to study the universe. The landmark detection of the first signal in 2015, GW150914, confirmed a century-old prediction of General Relativity, initiating the field of Gravitational-Wave Astronomy. Ten years after this first detection, the LVK Collaboration has published...
We use state-of-the-art cosmological hydrodynamical simulations of galaxies within a cold dark matter context, to study recent ‘hot topics’ in galaxy formation at the smallest scales: the existence of low-surface-brightness, ultra diffuse galaxies, the emergence of 'dark galaxies' as well as the role of AGN feedback in the evolution of dwarfs. These predictions, together with future...
The IceCube Collaboration employs two primary detection channels: tracks and cascades. Point source searches with tracks, with their good angular resolution, are particularly sensitive to sources in the northern sky, while searches with cascades offer enhanced energy resolution and are more effective in the southern sky. Historically, high-energy neutrino point-source searches using IceCube...
We present power spectra of the cosmic microwave background (CMB) anisotropy in temperature and polarization, and the most recent constraints on cosmology from these, as measured from the Data Release 6 (DR6) of the Atacama Cosmology Telescope (ACT) data. ACT DR6 measures the CMB power spectra over a quarter of the sky in multiple bands in both temperature and polarization with arcminute...
The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector operating on the International Space Station. Since 2011, AMS has collected more than 250 billion charged cosmic rays with energies up to multi-TeV. The high-precision measurements with ~1% accuracy have led to many surprising observations. The latest results on cosmic elementary particles (electrons, positrons,...
The SuperCDMS SNOLAB experiment is an upcoming direct detection dark matter experiment using semiconductor crystal detectors operated at cryogenic temperatures. The experiment is located 2 km underground in the Creighton mine at Sudbury, Canada. With low background from cosmic sources, SNOLAB is ideal for rare event searches. The experiment uses 24 detectors, made of silicon and germanium,...
The CALorimetric Electron Telescope (CALET) has been in operation on the International Space Station (ISS) since October 2015, providing nearly ten years of high-precision, continuous observations of cosmic rays. The CALET mission aims to search for signatures of nearby sources and dark matter through observations of high-energy cosmic-ray electrons, and to contribute to the study of...
The TESSERACT experiment, a novel and fully funded new type of low-mass DM experiment, is achieving new sensitivities in the search for sub-GeV dark matter. We're deploying multiple complementary targets read out via ultra-sensitive TES-based athermal phonon detectors Each detector is uniquely tailored to detect nuclear-, electron-, and dark photon-type dark matter interactions. By using...
In 2017, the IceCube observatory associated (at a significance level of 3σ) a high-energy (HE, E ≥ 100 TeV) muon neutrino temporarily and spatially coinciding with an electromagnetic flare in blazar TXS 0506+056. Since then, no individual blazar-neutrino association at the same level of significance has been made. In November 2010, flat-spectrum radio quasar (FSRQ) 3C 454.3 had an...
Axion-like particles (ALPs), radiated from a network of cosmic strings, may be a large part of Dark Matter (DM). In the era of precision cosmology, it is possible to characterize the effect of such particles - which almost scale invariant distribution function spans many orders of magnitudes in momentum - on the observables. In this work, we employ the CLASS code and cosmological data to place...
Tonne-scale noble liquid detectors have set strong limits on Dark Matter (DM) candidates particularly above a few GeV/c², while the parameter space for Light Dark Matter (LDM) remains largely unexplored. A sub-keV energy threshold and large exposures are essential to tackle this challenge. Solid state detectors can achieve energy thresholds in the order of 1 eV, but their relatively small...
Magnetic monopoles are a long-sought prediction of Grand Unified Theories (GUTs), yet their efficient production in the early universe would lead to a monopole abundance that far exceeds observational limits—a challenge known as the cosmological monopole problem. The standard resolution invokes inflation occurring after monopole production, diluting their density to undetectable levels and...
The ANAIS (Annual modulation with NaI(Tl) Scintillators) experiment is intended to search for dark matter annual modulation with ultrapure NaI(Tl) scintillators in order to provide a model independent confirmation or refutation of the long-standing DAMA/LIBRA positive annual modulation signal in the low energy detection rate, using the same target and technique. Other experiments exclude the...
The IceCube Neutrino Observatory has detected TeV-scale neutrinos from NGC 1068, supporting the hypothesis that active galactic nuclei (AGN) may host high-energy neutrino production in obscured environments. Motivated by this, we investigate a catalog of intrinsically X-ray bright Seyfert galaxies in the Southern sky using a coronal model, which suggests cosmic-ray acceleration and hadronic...
Gamma-ray bursts (GRBs) of long duration arise from ultra-relativistic jets that appear shortly after the collapse of massive stars. The highly variable prompt emission, lasting only a few minutes, results from internal dissipation within the jet and is followed by an afterglow that can last several days. This afterglow emission, observable at energies ranging from radio to TeV, is primarily...
Measurements of clock isotopes, particularly that of the Be-10/Be-9 ratio, can be used to provide unique information on galactic cosmic ray propagation. The High Energy Light Isotope eXperiment (HELIX) is a balloon-borne magnet spectrometer designed to measure cosmic ray isotopes with an event-by-event mass resolution of 3%. The experiment aims to improve the statistics and extend measurements...
In this work, we employ a model-independent approach to jointly reconstruct the dark energy equation of state $w_\mathrm{DE}$ and the sum of neutrino masses $\sum m_\nu$.
We adopt the Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) method with five fixed nodes in which we allow $w_\mathrm{DE}$ and $\sum m_\nu$ to vary. We employ CMB, BAO and SN data to constrain the values of...
The detection of Gamma-Ray Bursts (GRBs) at Very High Energy (E > 100 GeV) was a long-awaited result, and many observations were needed before achieving this goal. The study presented here is based on a complete re-analysis of 15 years of GRB observations with the High-Energy Stereoscopic System (H.E.S.S.) providing the most extensive set of VHE upper limits to date.
This study contributes to...
Although the existence of a flux of high energy neutrinos emitted by extragalactic sources is well established, only two individual sources have been identified with high confidence: the blazar TXS 0506+056 and the Seyfert galaxy NGC 1068. We will review the results of observations of other Seyfert galaxies in the northern sky, and discuss the implications of both northern and southern...
SABRE is an international collaboration that will operate similar particle de-
tectors in the Northern (SABRE North) and Southern Hemispheres (SABRE
South). This innovative approach distinguishes possible dark matter signals
from seasonal backgrounds, a pioneering strategy only possible with a southern
hemisphere experiment. SABRE South is located at the Stawell Underground
Physics Laboratory...
The Trans-Iron Galactic Element Recorder (TIGER) family of instruments are designed to make the best single-element resolution measurements of the Ultra-Heavy Galactic Cosmic Rays (UHGCRs) to probe their origins and the sources of nucleosynthesis. The TIGER and SuperTIGER stratospheric long-duration balloon-borne detectors have each had two successful flights from Antarctica, with TIGER making...
Analysis of anisotropy of the arrival directions of galactic positrons, electrons and protons has been performed with the Alpha Magnetic Spectrometer on the International Space Station. This measurement allows to differentiate between point-like and diffuse sources of cosmic rays for the understanding of the origin of high energy positrons or the hardening in the proton flux. The AMS results...
Multimessenger follow-up observations triggered by high-energy neutrino signals offer a powerful method for identifying cosmic ray sources, particularly when the sources are transient. In the energy range of neutrinos above 100 TeV, X-ray transients are a plausible source candidate, especially if the cosmic neutrino background radiation above 100 TeV originates from the same class of objects...
By employing high-purity NaI as a cryogenic bolometer target material, the upcoming COSINUS experiment aims at providing a definitive crosscheck of the DAMA/LIBRA dark matter claim within the next few years. This approach is made possible through the dedicated „remoTES" detector design, which allows to readout the NaI crystal using a transition edge sensor without exposing it to fabrication...
We present results over an 11-year Solar cycle of cosmic antiprotons in the rigidity range from 1.00 to 41.9 GV. The antiproton fluxes exhibit distinct properties. Compared with other cosmic elementary particle fluxes (proton, electron, and positron), the magnitude of the antiproton flux temporal variation is significantly smaller. A hysteresis between the antiproton fluxes and the proton...
Accurate modeling of the early X-ray emission in short GRBs is essential for probing the GRB engine, understanding jet physics, and improving electromagnetic follow-up of gravitational wave signals from binary neutron star mergers in the context of multi-messenger astronomy.
Thanks to the operation of the Swift satellite over the last 20 years, we now have access to an extensive archive of...
Neutrino telescopes offer unique insights into some of the most extreme and energetic phenomena in the Universe. The ANTARES detector, which operated for 16 years off the coast of Toulon (France) until 2022, has played a pioneering role in deep-sea neutrino observations. The next-generation KM3NeT neutrino telescopes, ORCA and ARCA, designed to push the boundaries of atmospheric and...
Composite dark matter models, where dark matter exists in bound states formed in the early universe, have long been a source of scientific interest. I will focus on loosely bound dark matter composite states, where the binding energy per constituent is small compared to the constituent’s bare mass. If this binding energy is sufficiently small, scattering with Standard Model nuclei will...
The IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the South Pole instrumented within deep Antarctic ice. Recently, IceCube has reported evidence of TeV-scale neutrino emission from NGC 1068, a nearby Seyfert II galaxy, suggesting that active galactic nuclei could be potential sources of astrophysical neutrinos. Searches for time-dependent 10 GeV to 1 TeV...
Recently, the South Pole Telescope (SPT) released its measurements of temperature (T) and E-mode polarization power spectra of the cosmic microwave background (CMB). These measurements, made by two years of observation of 4% of the sky, are the most precise in EE and TE spectra for the multipole ranges 1800-4000 and 2200-4000, respectively. When combined with ACT-DR6 and Planck data, these...
Space-based gamma-ray observations have established sharp cutoffs at a few GeV as a common feature of pulsar emission, with the Crab pulsar until recently the only source detected above 100 GeV. Observations with imaging atmospheric Cherenkov telescopes (IACTs), such as H.E.S.S., now reveal pulsar spectra extending up to tens of TeV. For the Vela pulsar, we detect a distinct radiation...
Tensions between independent cosmological probes continue to challenge the $\Lambda$CDM framework. The persistent ~5$\sigma$ discrepancy between early- and late-time determinations of the Hubble parameter remains unresolved, while recent DESI BAO measurements, when interpreted within $\Lambda$CDM, yield constraints on the sum of neutrino masses that increasingly conflict with lower bounds from...
The IceCube Neutrino Observatory has provided new insights into the high-energy universe, unveiling neutrinos from the galactic plane to extragalactic supermassive black holes. In this work, we present a 12.3-year, full-sky, all-flavor dataset, the IceCube Multi-Flavor Astrophysics Neutrino sample (ICEMAN). ICEMAN is the combination of three largely independent neutrino samples of different...
The recent observation of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) from solar $^8$B neutrinos by the XENONnT and PandaX-4T collaborations marks the onset of the neutrino fog in direct dark matter detection experiments. This opens up new possibilities to explore the interplay between CE$\nu$NS and WIMP-nucleus scattering within a common theoretical framework. In this work, we...
Over the past two decades, the discovery of pulsed very-high-energy (VHE) emission of the Crab pulsar, along with the expansion of the gamma-ray pulsar catalogue driven by the Fermi-LAT satellite, has led to a paradigm shift in the understanding of the gamma-ray emission of pulsars. Once believed to originate near the neutron star’s surface, particle acceleration and radiative processes are...
We present high statistics measurements of the secondary cosmic rays Lithium, Beryllium, Boron, and Fluorine based on 11.5 years of AMS data. The properties of the secondary cosmic ray fluxes and their ratios to the primary cosmic rays Li/C, Be/C, B/C, Li/O, Be/O, B/O, and F/Si are discussed. The systematic comparison with the latest GALPROP cosmic ray model is presented.
We present a comprehensive analysis of the effects of models with very low reheating scenarios ($T_\text{RH} \sim \mathcal{O}(\text{MeV})$) on the cosmological observables and derive corresponding bounds on the reheating temperature. With respect to previous work, our study includes a more precise computation of neutrino distribution functions, leveraging the latest datasets from cosmological...
Gamma-ray emission from the plane of the Milky Way is understood as partly originating from the interaction of cosmic rays with the interstellar medium. The same interaction is expected to produce a corresponding flux of neutrinos. In 2023, IceCube reported the first observation of this galactic neutrino flux at 4.5𝜎 confidence level. The analysis relied on neutrino flux predictions — based on...
Pulsar wind nebulae (PWNe) are bubbles of relativistic particle outflows, primarily composed of electrons and positrons, which are continuously injected from pulsars and often exhibit broadband non-thermal radiation originating from synchrotron and inverse Compton scattering emission. Recently, LHAASO and HAWC observations have detected Ultra-High-Energy (UHE, E>100 TeV) gamma-ray sources...
Axiogenesis links the baryon asymmetry and dark matter abundance through the dynamics of the QCD axion, but its minimal form overproduces dark matter and can exacerbate the QCD axion quality problem. In this talk, I’ll show how these issues are naturally resolved in an axiverse framework, where the QCD axion arises from multiple interacting axions. This setup generates large axion velocities...
Atomic transitions are among the most studied and precisely measured phenomena in physics, making them an attractive probe for new physics. If dark matter (DM) interacts with electrons, it could trigger electronic transitions via the absorption or scattering of DM with the atom's electrons. The selection rules for these transitions depend on the Lorentz structure of the DM interaction. An...
A point-like gamma-ray source (HESS J1745–290) has been detected in the inner Galactic Center, spatially coincident with Sagittarius A (Sgr A). However, the currently quiescent state of Sgr A* challenges its interpretation as the origin of the emission. An alternative explanation is that a single pulsar wind nebula (PWN) accounts for the observed signal. However, X-ray observations have...
Galactic sources are key to understanding cosmic-ray acceleration and the extreme astrophysics environment in the Milky Way. Some of these sources are expected to emit both gamma rays and neutrinos: while gamma rays trace high-energy particle interactions, neutrinos provide a direct probe of hadronic acceleration processes. To study these phenomena, observatories with broad energy coverage and...
Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of the deuteron ($D$) flux are presented. The measurements are based on 21 million $D$ nuclei in the rigidity range from 1.9 to 21 GV collected from May 2011 to April 2021. We observe that over the entire rigidity range the $D$ flux exhibits nearly identical time variations with the $p$, $^3$He ,...
There has been ongoing debate about the potential unconfirmed asymmetric structure of the diffuse $\gamma$-ray emission of the Geminga halo. In this work, we adhere to first principles, injecting and propagating individual cosmic ray (CR) electrons in 3D realizations of turbulent magnetic fields characterized by Kolmogorov turbulence and Bohm turbulence. The particle motion is governed by the...
Beryllium nuclei in cosmic rays are expected to be secondaries produced by the fragmentation of primary cosmic rays during their propagation in the Galaxy. Therefore, their fluxes contain essential information on cosmic ray propagation and sources. As the radioactive isotope 10Be decays to 10B with a half-life comparable to the cosmic-ray residence time in the Galaxy, the 10Be/9Be ratio can be...
Recently, the James Webb Space Telescope (JWST) has found early galaxies producing photons from more efficient ionization than previously assumed. This may suggest a reionization process with a larger reionization optical depth, $\tau_{reio}$, in some mild disagreement with that inferred from measurements of cosmic microwave background (CMB). Intriguingly, the CMB would prefer larger values of...
The DAMIC-M collaboration recently reported impressive bounds on sub-GeV dark matter, robustly testing both thermal and non-thermal models for the very first time. In this work, we derive novel bounds from the recent PandaX-4T ionization S2-only search for Coherent Elastic Neutrino Nucleus Scattering (CEνNS). We find that the PandaX-4T S2-only data is able to compete with the DAMIC-M results,...
We present updated predictions for the very-high-energy neutrino and gamma-ray flux from the Galactic Plane. Our calculations account for both the diffuse emission generated by cosmic-ray interactions with interstellar gas and the cumulative flux from sources too faint to be resolved by current neutrino or gamma-ray telescopes. The diffuse flux estimates incorporate various assumptions...
We use the Mochima suite of cosmological zoom-in simulations (arXiv:2004.06008) to examine how different star formation and feedback models shape the dark matter distribution in a Milky Way–mass galaxy and its satellites (arXiv:2301.06189). All runs share identical initial conditions, allowing controlled comparisons across subgrid prescriptions. In every hydrodynamical case, the host halo...
The Milky Way hosts astrophysical accelerators capable of producing high-energy cosmic rays. These cosmic rays can interact with the interstellar medium across the Galaxy to produce neutrinos and gamma rays (propagation component), while their interactions with ambient material at their acceleration sites, such as supernova remnants, can give rise to source component of the gamma-ray and...
Pulsar halos—extended regions of relativistic electrons surrounding middle-aged pulsars—offer critical insight into cosmic-ray acceleration and transport in the interstellar medium. These sources are often bright in the TeV gamma-ray band due to inverse Compton scattering by the most energetic electrons, which are also expected to emit synchrotron radiation in the X-ray band. A multiwavelength...
I combine the non-relativistic effective theory of dark matter (DM) - electron interactions with linear response theory to obtain a formalism that fully accounts for screening and collective excitations in DM-induced electronic transition rate calculations for general DM-electron interactions. In the same way that the response of a dielectric material to an external electric field in...
Based on arXiv: 2409.13022 and arXiv: 2504.15340 (both published in ApJ Letters) We update constraints on cosmological parameters in a 12-parameter model, which extends the standard 6-parameter ΛCDM to include dynamical dark energy and massive neutrinos, along with other new parameters. We use the latest Planck PR4 (2020) likelihoods, DESI DR1 & DR2 BAO, and the latest uncalibrated type Ia...
TeV “halos” discovered around Geminga and Monogem by HAWC expose pockets of severely quenched particle diffusion close to middle-aged pulsars. Resolving the properties of these slow-diffusion zones, such as the size of the slow-diffusion zone, and local magnetic field strength, is pivotal for modelling lepton transport and for assessing the pulsars’ contribution to the local positron excess....
The electron + positron cosmic-ray flux recently released by the H.E.S.S. telescope shows a remarkable behaviour: It breaks at around 1 TeV and falls off quickly, following a smooth powerlaw. This is in tension with simple pulsar models, which predict a much harder electron spectrum at tens of TeV. However, in two-zone diffusion models, propagation of high-energy electrons is inhibited in a...
As the search for dark matter progresses, it is useful to refine past and future searches for heavy dark matter, including for dark matter masses well above a TeV. We show the importance of properly modeling the local dark matter velocity distribution, beyond the standard Maxwellian halo model, and in particular how accurate modeling of the Large Magellanic Cloud and Milky Way impact heavy...
Young massive stellar clusters (YMSCs) have emerged as energetic non-thermal sources, after the recent observation of extended gamma-ray emission by a dozen YMSCs. The large size of their gamma-ray halos, of the order of the excavated bubble from the collective wind, makes the detection of individual YMSCs rather challenging because of the low surface brightness. As a result, the emission from...
Space-based gamma-ray observatories provide continuous, all-sky coverage from a few hundred keV to hundreds of GeV, bridging the hard X-ray and very-high-energy domains accessible from the ground. Instruments such as Swift-BAT, INTEGRAL, Fermi-GBM, and Fermi-LAT, among others, have enabled precision studies of non-thermal processes in astrophysical sources, cosmological measurements through...
The origin and nature of cosmic rays remain some of the most intriguing questions in astroparticle physics. This talk will review the latest developments in CR physics, focusing on findings from major air shower arrays operating in hybrid mode. Key results on the CR energy spectrum, composition, and arrival directions will be presented. The talk will also highlight the future prospects for CR...
Neutrinos herald the dawn of multi-messenger astronomy, carrying signatures of the yet mysterious physics governing the most energetic sources in our universe. Recent developments on the role of neutrinos in cosmic sources will be reviewed together with the most exciting multi-messenger detection prospects.
The direct detection of gravitational waves has opened a new observational window onto the Universe, transforming both fundamental physics and astrophysics. A global network of ground-based interferometers — including the Advanced LIGO, Advanced Virgo, and KAGRA detectors — is now operating at unprecedented sensitivities, routinely detecting signals from compact binary coalescences. I will...
Modern Cosmology has become a precise discipline thanks to immense improvements in Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) observations, in addition to an ameliorated theoretical description of cosmological models. However, this precision uncovered tensions between datasets that challenge the standard model of Cosmology, ΛCDM. In this talk, I present a brief overview...
The origin and nature of cosmic rays remain one of the most intriguing unsolved problems in modern astrophysics, even more than a century after their discovery.
The Telescope Array (TA) is the largest cosmic ray observatory in the northern hemisphere, continuously observing ultra-high energy cosmic rays (E$>10^{18}\,$eV) with a hybrid detector composed of fluorescence detectors (FD) and a...
Cygnus X-3 is a microquasar consisting of a compact object of unknown nature and a Wolf-Rayet star, which orbit each other with a very short period of 4.8 hours. The compact object launches powerful jets that are an excellent site for particle acceleration up to relativistic energies. The presence of these relativistic particles, combined with the proximity to the star and its high luminosity,...
The IceCube Neutrino Observatory at the geographic South Pole has achieved key milestones in neutrino astrophysics, including the discovery of a high-energy astrophysical neutrino flux and the correlation of neutrinos with flaring blazars and Seyfert galaxies. Building on this success, the IceCube Upgrade is scheduled for completion during the 2025/26 Antarctic summer season. It will add seven...
VERITAS is one of the world’s most sensitive very-high-energy (VHE; E > 100 GeV) gamma-ray observatories. Around half of its good-weather observations were targeted on active galactic nuclei (AGN). We present the recent efforts to reprocess the historical archive of VERITAS and produce a standardized, first VERITAS TeV AGN Catalog, and announce several new detections by VERITAS of AGNs at TeV energies.
Antimatter cosmic rays and gamma rays are powerful probes for indirect dark matter (DM) detection. In this talk, I will present the CosmiXs framework, which provides state-of-the-art predictions for the energy spectra of cosmic messengers—antiprotons, positrons, gamma rays, neutrinos, and antideuterons—produced from DM annihilation or decay. The spectra are calculated using the...
Ground-based full-sky studies of the angular distribution of arrival directions of ultra-high-energy cosmic rays require combining data from different observatories, such as the Pierre Auger Observatory and the Telescope Array, because no single array can cover all declinations. A working group comprising members from both the Pierre Auger and Telescope Array collaborations has been tasked...
Blazars are a subclass of active galactic nuclei in which the relativistic jet-component aligns closely with the observer’s line of sight. Due to this viewing geometry, the observed emission is dominated by the highly Doppler boosted non-thermal jet emission which originates from the jet. At optical/UV wavelengths the emission is produced by leptonic synchrotron emission from relativistic...
The Radio Neutrino Observatory in Greenland (RNO-G) will be, upon completion, the largest cosmic neutrino telescope that uses the in-ice radio detection mechanism. RNO-G is also the first radio detector of its kind, with each station having a combination of antennas deployed at different depths, the so-called shallow and deep components. With this approach, it is expected that RNO-G will be...
We explore the high-energy emission of cosmic messengers from galaxy clusters hosting active galactic nuclei (AGNs) such as Perseus. The main objective is to distinguish the emission from the central source, such as NGC $1275$, from the diffuse emission. Due to high magnetic field and large size of clusters, CRs with energy $\leq 10^{18}$ eV can be confined within these structures over...
The origin of ultra-high-energy cosmic rays (UHECRs) remains one of the most compelling open questions in astroparticle physics. The Pierre Auger Observatory, the world’s largest facility for cosmic ray detection, has provided unprecedented data to investigate anisotropies in UHECR arrival directions. At large angular scales, a significant dipolar modulation in right ascension has been...
Gamma-ray binaries are among the most extreme accelerators in the Galaxy, capable of producing photons at TeV energies. LS 5039, a well-studied high-mass X-ray binary, is one of the few systems known to emit modulated TeV gamma rays. We report the detection of orbital modulation in gamma rays from LS 5039 up to 100 TeV using over 2800 days of observations with the High-Altitude Water Cherenkov...
The study of cosmic rays with indirect detection searches provides a powerful tool to test the properties of dark matter (DM), especially through their potential imprints on the injection spectra. Adopting a model-independent approach, we systematically explore the characteristics of cosmic ray injection spectra arising from DM scenarios exhibiting a richer phenomenology. Our analysis goes...
Situated near Summit Station, Greenland in 2023 and 2024, the Radar Echo Telescope for Cosmic Rays (RET-CR) experiment searched for radar echoes produced by reflections from in-ice cosmic-ray (CR) cascades. These secondary cascades are generated by energetic CR air showers impacting a high altitude ice sheet and depositing a portion of their energy into the ice. They can be detected with radar...
Ultra-high-energy cosmic rays (UHECRs) get deflected by extragalactic magnetic fields (EGMFs) when they propagate from their sources to Earth. The spread of UHECRs around their source position provides a measure of the strength of the turbulent EGMFs between the UHECR sources and Earth. Recent results from the Pierre Auger Observatory suggest correlations between the arrival directions of...
The creation of anti-nuclei in the Galaxy has been discussed as a possible signal of exotic production mechanisms such as primordial black hole evaporation or dark matter decay/annihilation in addition to the more conventional production from cosmic-ray interactions. Tentative observations of cosmic-ray andideuteron and antihelium by the AMS-02 collaboration have re-energized the quest to use...
The binary system Eta Carinae is a unique laboratory to study particle acceleration processes under a wide range of conditions. Particles are thought to be accelerated at shocks forming in the wind collision region. Eta Carinae has been firmly established as a source of high-energy (HE) and very-high-energy (VHE) gamma-rays in Fermi-LAT and H.E.S.S. data in the last decade. With its highly...
The Payload for Ultrahigh Energy Observations (PUEO) is a balloon-borne radio detector for neutrinos at energies above 1EeV, scheduled to fly over Antarctica in the austral summer of 2025/2026. Through the observation of radio signals from neutrino interactions in the Antarctic ice sheet, PUEO can achieve an effective detection volume that is unparalleled by other experiments.
Charged leptons...
Active galactic nuclei (AGNs) are powered by accretion onto supermassive black holes (SMBHs), yet the mechanisms governing their energy output and the growth of SMBHs, particularly at high redshift, remain incompletely understood. Blazars, a subclass of AGNs with relativistic jets oriented close to our line of sight, are detectable across the electromagnetic spectrum, from radio to gamma rays,...
Gamma-ray binaries produce the majority of their multi-wavelength non-thermal emission at energies >1 MeV. These systems consist of an O/Be star and a compact object, which has been detected as a neutron star in 3 of the 9 systems. It is largely understood, then, that the VHE non-thermal emission in these systems originates in a stand-off shock that is produced when the stellar wind and/or...
Blazars show variability across the entire electromagnetic spectrum and over a wide range of timescales. In some cases, characteristic emission patterns have been observed, such as the multi-year modulation detected in PG 1553+113. Quasi-periodic oscillations (QPOs) can arise from various astrophysical mechanisms, including jet precession, accretion disk instabilities, and supermassive binary...
The IceCube Neutrino Observatory has discovered an extragalactic neutrino flux and observed neutrinos from the Milky Way. Even though two active galaxies, NGC 1068 and TXS 0506+056, are candidate neutrino sources, the classes of objects responsible for the extragalactic flux are not known. And the Milky Way flux should be a combination of yet to be identified individual sources as well as a...
One of the major challenges in astrophysics is the estimation of the mass composition of ultra-high-energy cosmic rays (UHECRs), ions with energies exceeding $1\,\text{EeV}$ of extraterrestrial origin. Due to the low flux of UHECRs, the direct detection of the particles is infeasible, which poses several challenges for estimating their mass. When a UHECR enters Earth's atmosphere, it will...
In this talk, we present our recent work on cosmic antimatter signatures from primordial black holes (PBHs). Light primordial black holes may have formed in the early Universe, and could contribute to the dark matter content of our Galaxy. Their Hawking evaporation into particles could lead to the production of antinuclei, which propagate and arrive at Earth as cosmic rays with a flux peaked...
At the edge of the Galactic supernova remnant (SNR) Vela Junior lies the pulsar PSR J0855-4644. Pulsars are among the most efficient particle accelerators in our Galaxy, making the study of this region of interest. PSR J0855-4644 has remarkable X-ray and radio features, revealing a pulsar wind nebula (PWN) structure along with a bow shock nebula. PSR J0855–4644 stands out as one of the highest...
Spinning super-massive black holes at the centers of galaxies can launch powerful magnetized jets. 3C 279 is an archetypal blazar with a prominent radio jet that undergoes broadband emission variability. In April 2017 and April 2018, the Event Horizon Telescope (EHT) observed 3C 279 with an unprecedented angular resolution of 20 micro-arcseconds. In parallel, an extensive quasi-simultaneous...
CORSIKA 8 is a modern Monte-Carlo simulation framework for particle showers in air and dense media. It is designed as a modular and modern C++ framework, providing the flexibility that is needed for current and future astroparticle physics experiments. In addition to the standard hadronic interaction models for air showers, it also includes the next generation models EPOS-LHC-R and QGSJetIII...
The detection of high-energy astrophysical neutrinos by IceCube has opened a new window on our Universe. While IceCube has measured the flux of these neutrinos at energies up to several PeV, much remains to be discovered regarding their origin and nature. Currently, the discovery of point sources of neutrinos is hindered by atmospheric neutrino backgrounds; likewise, astrophysical neutrino...
Energy calibration in indirect air shower detection presents a challenging problem due to the impossibility of controlled laboratory validation. Traditionally, hybrid measurements combining fluorescence detectors (FD) and surface detectors (SD) have relied on calibrating the SD using FD data, assuming that fluorescence measurements closely reflect the calorimetric principle. However, SD energy...
Astrophysical jets from powerful active galactic nuclei (AGN) have recently been proposed as promising probes of dark matter (DM) in the sub-GeV mass range. These jets accelerate cosmic rays (CRs) to very high energies, which can then interact with their environments to produce multiwavelength (MW) emission ranging from radio frequencies to TeV $\gamma$ rays. If DM consists of light particles,...
Radio-loud Active Galactic Nuclei (AGN) produce relativistic jets that are among the most energetic structures in the universe. These jets emit radiation across most of the electromagnetic spectrum, with their Spectral Energy Distribution (SED) typically exhibiting a double hump structure. The lower energy part of the SED is dominated by synchrotron emission from non-thermal electrons in the...
Core-collapse Supernovae (SN) release nearly all their binding energy as a burst of neutrinos of all three flavours. RES-NOVA addresses a major challenge in astroparticle physics by introducing a novel detection technique based on low-temperature calorimeters operated at the milliKelvin scale, exploiting Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) as detection channel.
CE$\nu$NS...
The 3.5 keV line is a purported emission line observed in galaxies, galaxy clusters, and the Milky Way whose origin is inconsistent with known atomic transitions and has previously been suggested to arise from dark matter (DM) decay. I show why the line cannot arise from DM decay, and then describe work in which collaborators and I reanalyzed the datasets providing the bulk of the evidence for...
On 2 July 2025, the Gamma-ray Burst Monitor (GBM) onboard the Fermi Gamma-ray Space Telescope detected three short-duration MeV transients with overlapping sky locations. These events, named GRB 250702D/B/E (DBE), were triggered within approximately 1-2 hours of one another. Follow-up observations of this unusually long MeV transient (lasting longer than 3 hours) by the Neil Gehrels Swift...
Blazars are strong neutrino source candidates owing to their high intrinsic power and Doppler boost. However, in the sub-PeV range, where IceCube is most sensitive, blazars are inefficient neutrino emitters, and models seem to require extreme proton luminosities. In this talk, I present a new leptohadronic blazar model that captures the energetics and the extended nature of the relativistic...
PG 1553+113 is a BL Lac object located at redshift z = 0.433. It is one of the most luminous extragalactic sources in the very-high-energy (VHE, E > 100 GeV) gamma-ray band, and it has been detected by all currently operating Imaging Air Cherenkov Telescopes (IACTs). A key feature of this source is the evidence of quasi-periodic modulation in high-energy (HE, E > 100 MeV) gamma rays detected...
Fifteen years of the Fermi Large Area Telescope (LAT) data in the halo region of the Milky Way (MW) are analyzed to search for gamma rays from dark matter annihilation. Gamma-ray maps within the region of interest (|l| < 60 deg, 10 < |b| < 60 deg) are modeled using point sources, the GALPROP models of cosmic-ray interactions, isotropic background, and templates of Loop I and the Fermi bubbles,...
Multimessenger observations, combining electromagnetic radiation and neutrinos, offer critical insights into the high-energy processes occurring in astrophysical sources. Recent coincident detections of high-energy neutrinos from the direction of blazars highlight them as ideal candidates for multimessenger modeling, and at the same time underscore the necessity of accurate modeling frameworks...
PG 1553+113 is a high-frequency peaked BL Lac object with a redshift of 0.433, detected by the current generation of Imaging Atmospheric Cherenkov Telescopes up to approximately 1 TeV. Interestingly, the continuous gamma-ray light curve recorded by Fermi-LAT since 2008 has shown a periodic modulation of 2.18 ± 0.08 years at energies above 100 MeV and 1 GeV. Additionally, the source shows clear...
Cygnus is a vast star-forming complex harbouring a population of powerful objects, including massive star clusters and associations, Wolf-Rayet stars, pulsars, and supernova remnants. The multi-wavelength picture is far from understood, in particular the recent LHAASO detection of multi-degree scale diffuse γ-ray emission up to PeV energies. In this talk, I demonstrate that hadronic emission...
The recent detection of high-energy neutrinos from NGC 1068 supports the idea that AGN coronae—magnetized, compact regions around supermassive black holes—can accelerate protons and produce neutrinos via photohadronic interactions with X-ray photons. I present a plasma-informed framework for this coronal scenario, grounded in particle-in-cell simulations of magnetic reconnection and...
We present preliminary results from a study of the anisotropy in cosmic-ray arrival directions as observed by IceTop, the surface array component of the IceCube Neutrino Observatory. IceTop is primarily sensitive to cosmic rays in the PeV energy range, providing complementary data to and extending beyond recently published results from IceCube’s in-ice component. This work uses 10 years of...
Massive young stellar objects (MYSOs) can drive high-speed, collimated outflows capable of propagating at hundreds of kilometers per second through the circumstellar medium. The strong shocks produced in the internal regions of these jets, as well as the powerful termination shocks, can create favorable conditions for particle acceleration. In this study, that has been published in the...
Weak-scale Dark Matter (DM) particles annihilating into lepton-rich channels in the Galaxy not only produce $\gamma$-rays via prompt radiation, but also generate abundant energetic $e^\pm$, which subsequently emit through inverse Compton scattering or bremsstrahlung (collectively called `secondary-radiation photons'). While the prompt $\gamma$-rays concentrate at high-energy, the secondary...
We present the first gamma-ray study of X-ray selected AGN in dwarf galaxies, using 15 years of Fermi-LAT data. These low-mass systems likely host intermediate-mass black holes and offer a unique view into accretion and feedback in the faintest galactic nuclei, as well as a new window into the properties of dark matter. While no individual source is detected, a joint likelihood analysis of 74...
We present a novel algorithm for both forecasting and recasting upper limits (ULs) on dark matter (DM) annihilation cross sections. The forecasting method relies solely on the instrument response functions (IRFs) to predict ULs for a given observational setup. The recasting procedure uses published ULs to reinterpret results for alternative DM models or channels, without requiring access to...
The Compton-Getting effect — an apparent dipolar anisotropy of cosmic rays generated by Earth's orbital motion around the Sun — serves as a known calibration source for cosmic-ray anisotropy studies. The amplitude of the Compton-Getting dipole depends on both the orbital speed and the mean spectral index of the cosmic-ray flux. It therefore provides an indirect method for studying the energy...
Markarian 501 is a well know close by (redshift = 0.034) BL Lac object. It is categorized as a high-synchrotron peaked blazar (HSP; νpeak> 10^{16} Hz) with temporarily extremely high-synchrotron peaked behavior (EHSP; νpeak> 10^{17} Hz). The proximity of the source allows for the observations in the Very High Energy range (VHE; E> 100 GeV) by IACTs, such as the MAGIC telescopes. In 2014, the...
Observation of high-energy neutrinos from the direction of the nearby active galaxy, NGC 1068, was a major step in identifying the origin of high-energy neutrinos. This observation revealed that high-energy neutrinos originated at the heart of active galaxies, which are opaque to very-high-energy gamma-ray emission. This realization is further reinforced by the multimessenger picture for the...
In recent years, massive star cluster environments have emerged as a new class of gamma-ray sources capable of accelerating particles to very-high energies, to such extent that they could complement the supernova model for the origin of galactic cosmic rays. The environment sculpted by the interaction of powerful stellar winds is complex, highly structured from small (pc) to large (100 pc)...
Muons, created by the interactions of cosmic rays with the Earth's atmosphere, form the main component of the cosmic ray air showers which reach underwater or in-ice detectors such as KM3NeT and IceCube. Precise measurements of such muons can provide key insights into the properties of cosmic rays, and their interactions. The KM3NeT research infrastructure consists of two telescopes in the...
M87* is a particularly well-studied black-hole system, thanks to the wealth of spectral data and the ability to image its central region using VLBI techniques. We present a model of the broadband emission of this object, in which radiation from the millimetre to TeV range is explained by leptonic emission from the innermost accretion flow. The model is based on GRMHD simulations and takes into...
We critically reassess the Minimal Dark Matter model and propose novel indirect detection signatures. Specifically, we compute the photon flux associated with the originally proposed accidentally stable SU(2) 5-plet, arising from Dark Matter bound state formation and Sommerfeld-enhanced annihilations. Our analysis reveals several distinctive spectral features that constitute promising targets...
The interactions of high-energy cosmic rays produce neutrinos and gamma rays. However, while neutrinos travel unimpeded, the accompanying gamma rays can trigger electromagnetic cascades via pair production on ambient photons, reprocessing their energy to lower frequencies. For intergalactic cascades produced in the propagation through extragalactic radiation, the resulting photons have a...
Gamma-ray observations have established that pulsar magnetospheres are efficient accelerators of electrons and positrons. Analytical models and numerical simulations further suggest that a fraction of a pulsar’s rotational energy can be converted into the acceleration of cosmic rays, positioning pulsars as potential contributors to the Galactic cosmic-ray population. However, direct...
LHAASO has recently detected ultra-high-energy (UHE, >100 TeV) γ-rays from various Galactic sources, including supernova remnants, pulsar wind nebulae, microquasars, and young massive clusters. The presence of these UHE γ-rays indicates the potential acceleration of cosmic rays to PeV energies. A leading explanation for this emission involves CRs from sources interacting with nearby molecular...
Our understanding of the $\gamma$-ray sky has improved dramatically in the past decade, however, the unresolved $\gamma$-ray background (UGRB) still has a potential wealth of information about the faintest $\gamma$-ray sources pervading the Universe. Statistical cross-correlations with tracers of cosmic structure can indirectly identify the populations that most characterize the $\gamma$-ray...
Galaxy clusters are the most massive gravitationally bound structures in the Universe. Even if clusters are nearly virialized structures, they undergo merging processes, creating merging shocks, and suffer from feedback from galaxies and AGNs; causing complex turbulent motions and amplifying their magnetic fields. These processes act as acceleration mechanisms for the plasma of the...
The Pierre Auger Observatory, the largest air-shower detector in the world, provides unmatched exposure to photons with energies above 5 × 10¹⁶ eV. Its hybrid detection system - combining a surface detector array and fluorescence telescopes - enables the most stringent upper limits on the diffuse Ultra-High-Energy photon flux, achieved through advanced discrimination of photon-induced air...
Despite growing statistics, the sources of most high energy neutrinos remain unknown. Here we present a tomographic approach that makes use of the angular, harmonic cross-correlation between IceCube data and galaxy surveys. If neutrino sources follow the Large Scale Structure (LSS), this cross-correlation will be non-zero and, if detected, it will determine how neutrino sources correlate with...
In 2010, the Fermi Gamma-ray Space Telescope observed two gamma-ray emitting structures, the Fermi Bubbles (FBs), that extend up to 55° above and below the Galactic plane and that seem to emanate from the Galactic center region. Although the spectrum at latitudes |b| > 10° has a softening or a cutoff around 100 GeV, the one at the base of the FBs, |b| <10°, extends up to about 1 TeV without a...
The QCD axion, originally proposed to resolve the strong CP problem, is also a compelling dark matter (DM) candidate. In strong magnetic fields, such as those surrounding neutron stars, axions can convert into photons, potentially generating detectable radio signals. This axion-photon coupling offers a unique avenue for experimental searches in a well-defined mass range. In this seminar, I...
NGC 4278 is a low-luminosity active galactic nucleus (AGN) in the local Universe. The detection of very-high-energy (VHE) gamma rays from NGC 4278 by the Large High Altitude Air Shower Observatory (LHAASO) has identified it as a newly discovered extragalactic TeV gamma-ray source. However, the physical origin of the VHE gamma-ray emission from NGC 4278 remains unclear.
In this study, we...
The field of ground-based gamma-ray astronomy is in the midst of a transformative era, with the current generation of instruments revealing a rich and intricate view of non-thermal astrophysics in the TeV–PeV energy range. At the same time, a new generation of observatories is being planned or built, promising a major step forward in our understanding of numerous astrophysical systems, as well...
Strong gravitational lensing at gamma rays is mostly unexplored, with only two confirmed strong lenses emitting at these energies. Despite their rarity, these two objects offer a unique window into high-energy astrophysical sources at high redshifts. The paucity of lenses at gamma rays is primarily due to challenges in detecting and confirming them using standard methods, as the angular...
The 21-cm hyperfine line of HI is set to revolutionize studies of the first billion years, spanning the cosmic dawn of the first stars and eventual reionization of our Universe. I will discuss the potential of this probe in learning about the unknown astrophysics of the first galaxies as well as physical cosmology. Preliminary claims of a detection of the mean (sky-averaged) 21cm signal...
The moment a neutrino event, likely of astrophysical origin, triggers a light emission in the glacial ice at the South Pole, the IceCube Neutrino Observatory issues a real-time alert to potential observers worldwide. The same filters that select alerts with track-like signatures were applied to the entire IceCube data sample from 2011 to 2023, leading to the public release of the IceCat-1...
The extragalactic background (EGB) observed by Fermi-LAT provides a detailed map of the non-thermal universe. We construct a simulation-based inference framework with the goal of characterizing the full information contained in the EGB. Using a convolutional neural network method, we provide the first simultaneous inference of the energy spectrum and source-count distribution (SCD) for the...
Axion-like particles (ALPs) appear in various extensions of the Standard Model and can interact with photons, leading to ALP-photon conversions in external magnetic fields. This phenomenon can introduce characteristic energy-dependent “wiggles” in gamma-ray spectra. The Cherenkov Telescope Array Observatory (CTAO) is the next-generation ground-based gamma-ray observatory, designed to provide...
In this talk, we summarize our research on stellar streams as a new and complementary target for dark matter (DM) searches with gamma rays.
Stellar streams whose progenitor is a dwarf galaxy (dG) are particularly interesting targets for DM searches, since dGs are thought to be highly DM-dominated systems. We expect these streams to have lost most of their DM content during the stretching...
Recently, LHAASO has announced the highest-energy measurements of the diffusive gamma-ray flux, offering the possibility of probing the spatial distribution and energy spectrum of the galactic cosmic rays (CRs) up to the all-particle spectrum knee ( PeV). However, a persistent tension between observations by experiments (such as Fermi and LHAASO) and the predictions based on measurements of...
The cosmic ray knee, observed at around 4 PeV, marks a striking feature in the all-particle cosmic ray spectrum and is widely regarded as the signature of the end of the Galactic component. Recent direct measurements from DAMPE, CALET, and ISS-CREAM are now probing the spectrum with unprecedented precision up to the vicinity of the knee, while LHAASO has provided groundbreaking indirect data...
About half of the Fermi-LAT gamma-ray sources within plus or minus 10 degrees in latitude from the Galactic plane are unassociated. Interestingly, the distribution of the Galactic unassociated sources as a function of spectral parameters is different from the distributions of known classes of Galactic sources, such as pulsars, supernova remnants, and pulsar wind nebulae. This difference in...
https://arxiv.org/abs/2506.01152
A number of studies assert that dark matter (DM) subhaloes without a baryonic counterpart and with an inner cusp always survive no matter the strength of the tidal force they undergo.
In this work, we perform a suite of numerical simulations specifically designed to analyse the evolution of the circular velocity peaks ($V_\mathrm{max}$, and its radial value...
Blazars are a class of active galactic nuclei, supermassive black holes located at the centres of distant galaxies characterised by strong emission across the entire electromagnetic spectrum, from radio waves to gamma rays. Their relativistic jets, closely aligned to the line of sight from Earth, are a rich and complex environment, characterised by the presence of strong magnetic fields over...
KM3NeT, a Cherenkov-based neutrino telescope sensitive to energies ranging from MeV to PeV, is currently under construction in the depths of the Mediterranean Sea. It comprises two detectors, KM3NeT/ARCA and KM3NeT/ORCA, already partially deployed and data taking; full completion is anticipated by the end of the decade. Its design provides a large field of view and high duty cycle, enabling it...
The IceCube Neutrino Observatory, situated at the South Pole, plays a pivotal role in multi-messenger astronomy by continuously monitoring the entire sky for high-energy neutrinos. This presentation highlights recent advancements in IceCube's real-time alert system, particularly focusing on the Gamma-ray Follow-Up (GFU) program and the innovative Neutrino FlareWatch platform. These...
The transition from diffusion to gradient-curvature drift as the dominant mechanism for the Galactic escape of cosmic rays (CRs) is considered a possible origin of the CR “knee". We studied the connection between antisymmetric diffusion and these drifts by performing test-particle simulations of CR propagation in synthetic turbulent magnetic fields using the Monte Carlo code CRPropa 3. We...
Sub-GeV, or light, dark matter (DM) has emerged as a compelling candidate for the observed DM in the universe. Unlike the canonical WIMP, light DM can account for the thermal relic abundance while evading nuclear recoil direct detection constraints, due to its limited momentum transfer. This motivates alternative search strategies, such as electron recoil direct detection and accelerator based...
Galactic cosmic-ray accelerators are identified efficiently by gamma-ray observations of space-borne and ground-based instruments. The gamma-ray sources observed so far, however, represent only the tip of the iceberg, a highly biased sample of the brightest and closest sources. Studying the population as a whole requires careful evaluation of the available data and their biases, stemming from...
The analysis generally applied to Imaging Atmospheric Cherenkov Telescopes data optimizes quality selection cuts, selecting a sub-sample of high-quality events, and computes a set of Instrument Response Functions (IRFs) for these events. All surviving events are treated as equal in quality, and are assumed to be well represented by a single set of IRFs, while the rest of the events are...
High center-of-mass electromagnetic (EM) interactions could produce decaying heavy leptons and hadrons, leading to neutrino generation. These processes might occur in the most extreme astrophysical and cosmological scenarios, potentially altering the expected gamma-ray and neutrino fluxes in both the hadronic and the leptonic pictures. For instance, neutrinos could arise from high-redshift EM...
A gamma-ray source has been identified at the center of the Sagittarius (Sgr) dwarf spheroidal. It is unclear whether the observed gamma-ray emission is from a millisecond pulsar population or from dark matter annihilation within the Sgr halo. Probing this ambiguity requires accurate knowledge of the Sgr dark matter distribution. However, since Sgr is in the process of tidal disruption, there...
Short gamma-ray bursts (GRBs) are some of the brightest transients in the universe. We show that heavy axion-like particles (ALPs) can be produced in the hot plasma of GRB fireballs. When produced in the earliest stages, they escape and decay outside the source. We demonstrate that the resulting prompt photon field arising from ALP decay is too rarefied to re-thermalize, effectively preventing...
The Cherenkov Telescope Array Observatory (CTAO) will be the next generation of very high energy (VHE) gamma-ray observatories, using Imaging Atmospheric Cherenkov Telescopes (IACTs) such as the LST-1 (Large-Sized-Telescope-1). In this contribution, we present a successful application of deep learning techniques for event reconstruction in real LST-1 data, using the CTLearn framework. The...
The origin of Galactic cosmic rays (CRs), particularly around the knee region ($\sim$3 PeV), remains a major unsolved question. Recent observations by LHAAASO suggest that the knee is shaped mainly by protons, with a transition to heavier elements at higher energies.
Microquasars -- compact jet-emitting sources -- have emerged as possible PeV CR accelerators, especially after detections of...
Supernova explosions are extreme cosmic events that may impact not only ordinary matter but also dark matter (DM) halos. In this talk, I explore the possibility that a fraction of supernova energy is released as dark radiation, which could transform a cuspy DM halo into a cored one, potentially explaining observed cores in some dwarf galaxies. Alternatively, limits on DM core sizes provide...
The mysterious sources of high energy cosmic rays must be able to explain the power-law flux in energy as well as the nuclear composition changes at spectral breaks. Interacting supernovae may be able to explain these observed features. We build on a self-consistent model of the shock formed between supernova ejecta and the circumstellar medium by accounting for the composition of accelerated...
Jupiter has long been considered a pre-eminent target for dark matter searches, due to its proximity, mass, and low astrophysical backgrounds. However, low-mass dark matter ($\leq$400 MeV) is expected to efficiently evaporate from the Jovian core via interactions with standard model particles, limiting searches for dark matter effects. We show that in the case of leptophilic dark matter,...
The Cherenkov Telescope Array Observatory (CTAO) marks the next generation of Imaging Atmospheric Cherenkov Telescopes (IACTs), offering a sensitivity increase of up to five to ten times over current instruments. Its first prototype, the Large-Sized Telescope (LST-1), is already in operation at the Roque de los Muchachos Observatory in La Palma, Spain. Deep learning methods have shown...
The all-sky very-high energy ($10^4$ - $10^6$ GeV) atmospheric muon flux, most recently measured by IceCube, shows a spectral hardening in the higher energy range, indicating a prompt component. Since the atmospheric muon neutrino flux at high energy, also measured by IceCube, is dominated by the astrophysical flux, only upper bounds on the prompt atmospheric muon neutrino flux contribution...
Tau neutrinos, being most likely of astrophysical origin, plays a crucial role in solving cosmic‐ray–related puzzles. In IceCube, iterations of searches for tau neutrinos via their characteristic “double-cascade” / "double pulse” morphology have been conducted. However, this signature is not unique to tau neutrinos: the much less studied charmed production can lead to a similar signature due...
Graph Neural Networks (GNNs) have emerged as a robust architectural choice for deep learning across scientific disciplines, and are particularly suited for datasets with irregular topology. The MAGIC Telescope, comprising a pair of 17 m Imaging Atmospheric Cherenkov Telescopes (IACTs) located at Roque de Los Muchachos Observatory in La Palma, Spain, is designed to detect gamma rays from around...
The study of UHE $\gamma$-ray emission plays a key role in identifying the astrophysical accelerators responsible for producing $\sim$ PeV particles and shaping the Galactic cosmic-ray population. SNR G69.7+1.0 has recently attracted attention due to its association with the LHAASO source 1LHAASO J2002+3244, which emits above 100 TeV. This spatial coincidence provides a unique opportunity to...
The General Antiparticle Spectrometer (GAPS) is a balloon-borne cosmic-ray experiment designed to search for light antinuclei at kinetic energies below 0.25 GeV/n, a largely unexplored range that may carry distinctive signatures of dark matter.
The instrument consists of a ten-layer lithium-drifted silicon tracker, cooled by a novel oscillating heat pipe thermal system, and is enclosed on all...
Apart from its gravitational interactions, dark matter (DM) has remained so far elusive in laboratory searches. One possible explanation is that the relevant interactions to explain its relic abundance are mainly gravitational. In this work we consider an extra-dimensional Randall-Sundrum scenario with a TeV-PeV IR brane, where the Standard Model is located, and a GeV-TeV deep IR (DIR) one,...
Over the past decade, high-energy neutrino events have been piling up, resulting in a large statistical dataset covering a broad range of energies and directions. As neutrinos traverse the Earth, they undergo energy- and angle-dependent attenuation, which encodes information about the neutrino–nucleon cross section. In this work, we extract the neutrino–nucleon cross section using a large...
Since 2010, the JEM-EUSO (Joint Exploratory Missions for Extreme Universe Space Observatory) collaboration has been developing an ambitious program to observe Ultra-High-Energy Cosmic Rays (UHECRs) and related phenomena from space. These particles, with energies exceeding 10²⁰ eV, carry crucial information about the most extreme astrophysical environments, yet are difficult to study due to...
While there exists overwhelming evidence pointing to the existence of dark matter (DM) as one of the components of the Universe, “what is the nature of DM?”, remains as one of the unsolved puzzles of modern physics. Several hypotheses and theories propose a new kind of particle to explain DM. Among them, candidates as Weekly Interactive Massive Particles (WIMPs), and ultra-light DM as...
In the framework of open quantum systems, neutrino may interact with their surrounding environment, introducing stochastic fluctuations to their quantum phase. This perturbation causes a gradual loss of coherence during neutrino propagation, a phenomenon known as decoherence, which alters the neutrino oscillation probabilities.
KM3NeT/ARCA is a water Cherenkov detector currently under...
Dwarf irregular galaxies (dIrrs) are rotationally supported galaxies, located in the Local Volume, and are considered to host star-forming regions with a low star-forming rate. Their gamma-ray background signal is expected to be low, making them interesting targets for WIMP Dark Matter (DM) indirect searches. Following previous works on dIrrs, we present the best four dIrrs targets for the...
Ultra-high energy cosmic rays (UHECRs) above 100 PeV can be detected from space by looking towards the Earth's limb, where the optical emission from extensive air showers (EAS) can be observed. Space-based experiments can also play a crucial role in the multi-messenger astrophysics era, particularly through the detection of Earth-skimming neutrinos. Validating the observational techniques used...
Core-collapse supernovae (CCSNe) are explosive astrophysical events that emit radiation across the entire electromagnetic spectrum, extending up to soft gamma rays. Very high-energy (VHE; E > 100 GeV) gamma-ray emission is expected to arise from shock interactions between dense circumstellar material and the supernova ejecta. However, no unambiguous detection has yet been achieved by past or...
Charm-induced di-muons observed in neutrino experiments have played a pivotal role in advancing our understanding of quantum chromodynamics. IceCube is positioned to observe di-muon events at energies beyond those available to previous neutrino beam experiments, thereby probing novel regions of light quark dynamics within the proton. In this presentation, I will discuss the current status of...
Primordial black holes (PBH), while still constituting a viable dark matter component, are expected to evaporate through Hawking radiation.
Assuming the semi-classical approximation holds up to near the Planck scale, PBHs are expected to evaporate by the present time, emitting a significant flux of particles in their final moments, if produced in the early Universe with an initial mass of...
The main objective of the international JEM-EUSO (Joint Exploratory Missions for Extreme Universe Space Observatory) Collaboration is to develop a large mission with dedicated instrumentation looking down on the Earth atmosphere from space, both towards nadir and/or towards the limb, to detect the Extensive Air Shower (EAS) and the High Altitude Horizontal Airshowers (HAHA) initiated by...
Models predict that the Sun can produce bright gamma-ray emission through two separate mechanisms. First, ambient cosmic-ray protons can undergo hadronic interactions with the solar atmosphere producing a bright flux across the solar disk. Second, cosmic-ray electrons can inverse-Compton scatter ambient sunlight to gamma-ray energies.
Observations by the Fermi-LAT and HAWC telescope have...
We present new constraints on neutrino secret interactions (νSI) using high-energy and ultra high-energy astrophysical neutrinos as probes of new physics beyond the Standard Model. By studying neutrinos from established sources, such as SN1987A, NGC 1068, TXS 0506+056, PKS 0735+178, and the extreme-energy KM3-230213A event, we explore the potential interactions of Dirac neutrinos with a...
Axions and axion-like particles (ALPs) are hypothetical particles predicted by several extensions of the Standard Model and compelling dark matter candidates. Their conversion into photons in the presence of magnetic fields can leave distinctive imprints on the photon spectra of astrophysical sources. In gamma-ray astronomy, photon-ALP conversions may produce observable energy-dependent...
The Intergalactic Magnetic Field (IGMF), though significantly weaker than the Galactic Magnetic Field (GMF), is believed to permeate the vast cosmic voids. Recent experimental developments have provided both upper and lower bounds on the IGMF, motivating us to revisit the scenario in which Magnetic Monopoles (MMs) are accelerated by these large-scale fields. In this work, we analyze MM...
We investigate the effects of Lorentz invariance violation (LIV) on photon interactions, considering both intergalactic propagation (Breit-Wheeler process) and atmospheric interactions (Bethe-Heitler process). By incorporating LIV into the theoretical framework, we analyze how it modifies key quantities such as the cross section, threshold energy, and mean free path of photons traveling...
Under the hypothesis that thermal relic particles populate the dark matter halo of the Milky Way, strong indirect signals in cosmic radiation are expected from the regions where the dark matter density is high. In particular, the Galactic Center is potentially hosting the largest indirect signal from dark matter pair-annihilation (or decay), which in many theoretically well-motivated models...
We present the first experimental evidence for in-ice radiofrequency emission from cosmic-ray-induced high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array trigger of the Askaryan Radio Array, we detect 13 events with impulsive radiofrequency pulses originating from below the ice surface. Considering only the arrival angles and...
Although the sources of astrophysical neutrinos are still unknown, they are believed to be produced by a diffuse population of sources in the distant universe. Measurements of the astrophysical flux can thus be sensitive to energy-dependent propagation effects, such as the very long baseline oscillations that would occur if neutrinos are quasi-Dirac. Assuming simple models of the source flux,...
The Radar Echo Telescope for Cosmic Rays (RET-CR) is a pathfinder experiment deployed at the Summit Station in Greenland, with a full data-taking run conducted in the summer of 2024. This experiment utilises the radar technique to search for an in-ice secondary cascade produced when the core of a high-energy cosmic ray air shower propagates into the high-altitude ice sheet.
Detecting a...
Lorentz invariance violation (LIV) is a speculated consequence of some models of quantum gravity. It is modelled as a modified dispersion relation of massless particles. One direct effect of LIV is energy-dependent photon group velocity. This hypothesis is tested by measuring time delays in the arrival of high-energy photons from astrophysical sources. Suitable targets are variable, distant...
Magnetic levitation technology offers force and displacement sensitivities at the quantum frontier, making it an attractive platform for probing the feeble interactions expected of beyond the Standard Model physics. Despite its promise, the case for magnetic levitation in fundamental physics applications is only just being built. In this talk, I will introduce two new experiments based on the...
Primordial Black Holes (PBHs) are hypothesized to have been formed in the Early Universe as a result of density fluctuations. In recent years, PBHs have gained attention, in part, for the possibility that they can account for a fraction or all the dark matter content of the Universe. PBHs formed with a mass around $10^{14}$g to $10^{15}$g should be evaporating in present times through the...
Among the few ways that allow or could allow us to probe the early Universe from the observation of a flux of primordial particles, there is one possibility which has been little studied: the observation today of high energy neutrinos which could have been emitted short after the Big Bang, from the decay or annihilation of early universe relics.
We perform a general study of such a...
The evidence of a Stochastic Gravitational Wave Background (SGWB) in the nHz frequency range is posed to open a new window on the Universe. A preferred explanation relies on a supercooled first order phase transition at the 100 MeV–GeV scale. I will address the feasibility of this solution by discussing viable dark sectors and their constraints, going from the particle physics model to the...
In this talk, I will present bounds on the variation of fundamental constants from the cosmic microwave background (CMB). In our theoretically motivated model, the variation is modulated by a scalar field that behaves as an ultralight dark matter (ULDM). We self-consistently compute the effects of the variation of constants on big bang nucleosynthesis (BBN) and propagate those effects to the...
Cosmological observations, such as Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB), provide vital insights into the early Universe, allowing us to trace its evolution to times as short as t∼0.01 s and to test extensions of the Standard Model. Accurately modeling the non-trivial dynamics of neutrinos in the decoupling era typically requires solving a system of Boltzmann...
To detect ultra-high-energy neutrinos, experiments such as the Askaryan Radio Array (ARA) and the Radio Neutrino Observatoy in Greenland (RNO-G), target the radio emission induced by these particles as they cascade in the ice, using deep in-ice antennas at the South Pole or in Greenland. In this context, it is essential to first characterize the in-ice radio signature from cosmic-ray-induced...
The Large Magellanic Cloud (LMC) is a satellite galaxy, orbiting the Milky Way at a distance of approximately $50 \text{kpc}$. This galactic neighbour contains some of the most luminous TeV gamma-ray sources; namely N$~$157B, the first extra-galactic pulsar wind nebula detected, the supernova remnant N$~$132D, the young massive stellar clusters 30$~$Dor$~$C and R$~$136, and the gamma-ray...
This presentation covers aspects - from a theoreticians point of view - of some recent developments on extragalactic low-power gamma-ray sources, with focus on active galactic nuclei.
The nature of dark matter, one of the most compelling open questions in fundamental physics, is still unknown. A comprehensive search program has developed over the past decades, spanning direct detection experiments, indirect detection via astrophysical signals, and collider-based production. In this talk, we focus on collider searches for dark matter, particularly at the Large Hadron...
Multimessenger astrophysics represents a unique opportunity to link particle physics, astronomy, and cosmology. The method for combining different observational probes has been opened up by the opportunity to relate traditional multiwavelength astronomy with the advent of refined and more sensitive neutrino detectors, γ-ray telescopes, gravitational wave interferometers, and space and...
In this talk I will review some recent developments in direct detection methods looking for wavelike dark matter including axion dark matter.
In this talk I will survey the complementarity of cosmological and laboratory probes with various developments in elementary particle theory, including dark sector physics and non-standard cosmological histories.
The MAGIC telescopes have been in operation for more than 20 years, after which thousands of hours of data have been collected. In spite of this, a large fraction of data sits underutilized after the analysis on the target source has been completed. The relatively small FoV of current generation IACTs results in a target based observation strategy, where telescopes are pointed to a gamma-ray...
Over the past 16 years, the Fermi Large Area Telescope (LAT) has significantly advanced our view of the GeV gamma-ray sky, yet several key questions remain - such as the nature of the isotropic diffuse background, the properties of the Galactic pulsar population, and the origin of the GeV excess towards the Galactic Centre. Addressing these challenges requires sophisticated astrophysical...
While remarkable progress has been made to understand the propagation of cosmic rays, a variety of astrophysical uncertainties persists. At energies below about 40 GeV, the cosmic-ray flux is significantly modulated by solar activity, a process that is not precisely understood. Using the recently published AMS-02 data for the time-dependent cosmic-ray fluxes, we study the effects of solar...
We present the development of a modular visible and UV detection system based on silicon photomultipliers (SiPMs), designed to support future space-based and sub-orbital missions targeting extreme astrophysical phenomena. This effort focuses on enabling high-resolution, low-power, and scalable instrumentation tailored for the detection of air-shower signatures produced by Ultra-High-Energy...
Identifying hadronic PeVatrons among ultra-high-energy (UHE) gamma-ray sources is challenging but crucial for understanding the origin of cosmic rays. The UHE source 1LHAASO J1857+0203u is suggested to be associated with HESS J1858+020, which may originate from PeVatron candidate supernova remnant (SNR) G35.6-0.4 or HII region G35.6-0.5. We present a detailed study of TeV gamma-ray emission in...
Over the past few decades, modern physics has resolved many fundamental
questions about the nature and structure of the universe. Yet, the origin of dark
matter remains one of its most compelling open problems. Among the
proposed candidates, Weakly Interacting Massive Particles (WIMPs) stand out
as particularly promising, and a significant research effort has been devoted to
their direct...
High-precision measurements from recent cosmic-ray experiments have provided crucial insights into Galactic cosmic-ray spectra across a wide energy range, revealing spectral hardening in the GeV--TeV region that challenges conventional models of acceleration and propagation. Re-acceleration of cosmic rays by weak shocks from old supernova remnants offers a promising explanation, accounting for...
A considerable fraction of the energy from gamma-ray burst (GRB) jets, after generating the keV-MeV emissions, results in an ultra-relativistic shock that travels through the circumburst medium. This shock accelerates particles, resulting in afterglow emissions. Recently, a few GRB afterglows have been detected in TeV gamma-rays by Cherenkov Telescopes, offering a chance to examine the...
Due to its proximity and high Dark Matter (DM) content, the Galactic Center (GC) is one of the preferred targets in the search for DM. Even in the absence of clear signals, GC observations can be used to set the best DM constraints. Despite the GC being a crowded region, rich in very diverse gamma-ray astrophysical emissions, thanks to both its expected flux and angular sensitivity, the...
This study presents a solution for cosmic muons detection using a 3d shaped stack of multiple layers of parallelepiped prism scintillators, each scintillator being optically coupled to a silicon photomultiplier (SiPM) in a SiPM array of 8x8. As muons traverse the stack, they produce fast scintillation pulses detected with high sensitivity by the SiPMs. The multilayer configuration is scalable...
The recent detection of Very-High-Energy (VHE) emission from the Crab and Vela pulsars by Imaging Atmospheric Cherenkov Telescopes (IACTs) has revolutionised the field of gamma-ray pulsars. This discovery challenges the capability of classic curvature-radiation-based models to explain the overall gamma-ray emission from MeV to TeV energies. Geminga is the third IACT-detected pulsar. Despite...
The search for antideuterons in cosmic rays is considered a golden channel for probing the presence of dark matter annihilation in the galaxy. The PHeSCAMI project (Pressurized Helium Scintillating Calorimeter for AntiMatter Identification) focuses on developing novel techniques for the identification of antinuclei in cosmic rays. A particularly promising detection signature has been...
Magnetic fields permeate galaxies and clusters, yet their origin remains unclear. They are thought to arise from the amplification of weak seed fields, whose nature (cosmological or astrophysical) is still debated. If magnetic fields have a primordial origin, we expect even the cosmic voids of the Universe to carry traces of magnetization. One way to test this is through gamma-ray observations...
Supernova remnants are known to accelerate particles to relativistic energies on account of their non-thermal emission. Fast variability in the non-thermal synchrotron emission has been detected in multiple remnants and was linked to local properties of the magnetic fields. Further, variations in the long-term radio and x-ray flux have been reported for various objects as well.
RCW86 is one of...
The recent catalog published by the Large High Altitude Air Shower Observatory (LHAASO) Collaboration unveiled many new unidentified sources at Very-High-Energies (VHEs, E>50 GeV) and Ultra-High-Energies (UHEs, E>100 TeV), many of which lie near pulsars, reinforcing the hypothesis of pulsars as some of the most powerful accelerators in the universe. Among these, 1LHAASO J1740+0948u stands out...
Gamma astronomy, in the last few decades, has given us a lot of new information while leaving us with many unanswered questions. Afull understanding of a large number of observed gamma-ray sources is still far from being achieved. The sources detected by the LHAASO Observatory, in the range of Very High Energies (VHE), have been published in its first full catalogue in 2024. Out of the 90...
The coincident detection of high-energy $\gamma$-rays and neutrinos from TXS 0506+056 marks the first multimessenger detection involving neutrinos. The observation suggests the presence of hadronic acceleration in this source. Neutrino sources may also be $\gamma$-ray opaque, in which case the photons cascade down to lower energies before leaving the source. Determining the $\gamma$-ray...
Astrophysical flares are among the prime candidates for the production of ultra-high-energy (UHE, E > 10¹⁷ eV) cosmic rays. The trajectory of UHE neutral particles, such as photons, is not deflected in the presence of cosmic magnetic fields, in contrast with that of UHE charged particles, leading to a predictable clustering of events observed on Earth, correlated temporally and directionally....
The LISA mission is an all-sky monitor that will offer a wide view on a dynamic cosmos using gravitational waves as new and unique messengers to unveil the Gravitational Universe. As such, it will provide the closest ever view of the early processes at TeV energies and can probe the entire universe from its smallest scales around singularities and black holes all the way to cosmological...
IceCube's recent studies of one of the nearest Seyfert galaxies--the Circinus galaxy--suggest that it is a new candidate source of high-energy neutrinos, with a pre-trial significance reaching
3$\sigma$. As a Compton-thick AGN with a column density of $n_{\rm H} \sim 4 \times 10^{24}\rm~cm^{-2}$, the Circinus galaxy strongly obscures the photons produced near its core. To understand the...
One of the central unresolved questions in fundamental physics revolves around the postulated quantum structure of spacetime. Novel physical phenomena are expected as residual evidence of a more fundamental theory of nature. A critical aspect pertains to scrutinizing the hypothesized quantum structure of spacetime at the Planck’s scale and the related departures from the Lorentz symmetry,...
Axions are hypothetical pseudoscalar particles that naturally arise in
the Peccei-Quinn solution to the strong CP problem in QCD, and at the
same time provide one of the most compelling candidates for dark
matter. Among the various experimental approaches being pursued
worldwide, microwave cavity experiments are particularly well suited
to probe axions in the GHz frequency range.
Recent...
The epoch of reionization marks a key phase transition in the Universe’s history, typically attributed to the formation of the first stars and galaxies. However, a range of exotic early-Universe physics (decaying particles, low-temperature reheating, and axion-like fields) could introduce additional high-redshift ionization, leaving imprints on the cosmic microwave background (CMB)...
Nowadays, the origin of neutrino mass still remains unknown. One possibility is that massless neutrinos acquire a “refractive mass”, due to their interaction on ultralight dark matter while propagating towards the Earth. The future DUNE observatory would be able to discriminate this “dark” neutrino mass nature at high significance level. Under this assumption, we explore the DUNE projected...
One of the most important challenges of astroparticle detection via radio-based methods is the ability to correctly distinguish between the radio signals from the relevant mechanisms associated with particle-induced showers (i.e. geomagnetic and Askaryan effects) and all other impulsive and transient backgrounds. Background radio signals, regardless of origin, not only might mimic the desired...
Recent measurements by the LHAASO, ARGO, HAWC, and Tibet ASγ collaborations have provided unprecedented observations of Galactic diffuse γ-ray emission across various regions of the Milky Way, spanning energies from 1 TeV to 1 PeV. These data offer a unique opportunity to probe the nature of the most powerful Galactic cosmic-ray (CR) accelerators and to test models of CR acceleration and...
The identification of molecular clouds associated with supernova remnants (SNRs) is crucial for understanding the origin of Galactic cosmic rays and for quantifying the energy of cosmic ray protons. RCW 103 is a shell-type SNR with a bright radio continuum and thermal-dominated X-rays. The detection of GeV and TeV gamma-rays suggests that it is a promising site for the acceleration of cosmic...
The radiation models used in the interpretation of gamma-ray data are usually forced to include a number of simplifications to provide fast enough calculations to be used in fitting routines. We investigate the geometrical effects affecting the production and absorption of gamma-ray radiation emitted in inverse Compton scattering in the synchrotron-self-Compton process. The effect of the...
We present updated constraints on the coupling of thermally-produced axion-like particles with leptons and photons, derived from recent cosmic microwave background (CMB), baryon acoustic oscillation and big bang nucleosynthesis datasets. Additionally, we improve upon previous studies by using a more accurate axion distribution function obtained from solving the full Boltzmann equation, thereby...
IceCube has continuously performed all-sky searches for point-like neutrino sources using track-like events. In this talk, we discuss the public data release of neutrino candidates detected by IceCube between April 6, 2008 and May 23, 2022. An updated selection and reconstruction for data taken after June 2010 was implemented. These updates were not implemented in the previous point-source...
