Conveners
Parallel: Galactic
- Silvia Celli (INFN-Roma and Gran Sasso Science Institute)
Parallel: Dark Matter
- Csaba Balazs (Monash University)
Parallel: Particle Physics
- Michael Fedderke (Stanford University)
Parallel: Gamma Rays
- Markus Boettcher (North-West University)
Parallel: Extragalactic
- Miroslav Filipovic (Western Sydney University)
Parallel: Dark Matter
- Nicholas Rodd
Parallel: Gamma Rays
- Gavin Rowell (University of Adelaide)
Parallel: Neutrinos
- Mikhail Malkov (UCSD)
Parallel: Cosmic Rays
- Takashi SAKO (Institute for Cosmic Ray Research, University of Tokyo)
Parallel: Gamma Rays
- Susumu Inoue (RIKEN)
Parallel: Cosmology
- Matteo Fasiello (Institute of Cosmology and Gravitation)
Parallel: Dark Matter
- Pat Scott (The University of Queensland)
Parallel: Neutrinos
- Michael Schmidt (UNSW Sydney)
Parallel: Galactic
- Silvia Celli (INFN-Roma and Gran Sasso Science Institute)
Parallel: Gamma Rays
- Jamie Holder (University of Delaware)
Parallel: Cosmology
- Matteo Fasiello (Institute of Cosmology and Gravitation)
Parallel: Cosmic Rays
- Zurab Berezhiani (Univ. L'Aquila)
Parallel: Dark Matter
- Nicholas Rodd
Parallel: Gamma Rays
- Susumu Inoue (RIKEN)
Parallel: Neutrinos
- Jenni Adams (University of Canterbury)
Parallel: Dark Matter
- Thomas Nathan Thorpe (Gran Sasso Science Institute (IT))
Parallel: Cosmic Rays
- Francesca Calore (LAPTh, CNRS)
Parallel: Particle Physics
- Chia-Ling Hsu (University of Sydney)
Parallel: Particle Physics
- Peter Athron
Parallel: Dark Matter
- Ciaran O'Hare (Nottingham)
Parallel: Gravitational waves and followup
- Tara Murphy (University of Sydney)
Parallel: Extragalactic
- Miroslav Filipovic (Western Sydney University)
Parallel: Cosmology
- Emanuela Dimastrogiovanni (The University of New South Wales)
In this talk, I’ll present results from a global analysis of effective Higgs portal dark matter (DM) models in frequentist and Bayesian statistical frameworks. We use the GAMBIT software to determine the preferred mass and coupling ranges for vector, Majorana and Dirac fermion DM models. We also assess the relative plausibility of all four (including scalar DM) models using Bayesian model...
More than 50 years after the discovery of pulsars by Jocelyn Bell-Burnell and Antony Hewish, their study remains a very active field of research.
Although great progress has been made in the last decade in interpreting the high energy emission of pulsars, thanks in particular to the wealth of data from the Fermi-
LAT satellite borne telescope, there are still many open questions, specially...
The current generation of imaging atmospheric Cherenkov telescopes, complemented by ground-based particle detector arrays, have demonstrated that our Galaxy plays host to a wide variety of particle accelerators. These include supernova remnants, compact object binary systems and star forming regions, as well as pulsars and their extended nebulae and haloes. Bright TeV gamma-ray emission from...
Searches for beyond-Standard Model physics at the LHC have thus far not uncovered any evidence of new particles, and this is often used to state that new particles with low mass are now excluded. Using the example of the supersymmetric partners of the electroweak sector of the Standard Model, I will present recent results from the GAMBIT collaboration that show that there is plenty of room for...
Searches for electroweak production of neutralinos and charginos (electroweakinos) at the LHC have revealed a series of excesses over the predicted Standard Model background. GAMBIT analyses show that although the excesses are inconsistent in terms of simplified models, taken together within the framework of a non-simplified electroweakino effective field theory, searches with 36 fb^-1 of...
We perform a global fit of the pseudo-Nambu-Goldstone (pNG) dark matter (DM) that arises in a complex scalar singlet model with a softly broken global U(1) symmetry. The resulting pNG boson is massive and serves as a viable DM candidate. More importantly, as the pNG DM-nucleon cross-section is momentum-suppressed at tree-level, it provides a natural way of explaining the null results from...
The Geminga pulsar is one of the closest pulsars to Earth and as such is a potential local source of cosmic ray positrons and electrons. TeV emission around the Geminga pulsar has been detected by HAWC and MILAGRO, and found to be significantly extended. This makes detection of the gamma-ray emission challenging for IACTs due to their limited field of view. HAWC observations of the Geminga and...
Despite anticipation since the COS-B era, gamma-ray detections of particle-accelerating colliding-wind binary (CWB) systems are still not at all numerous even after a decade of Fermi-LAT observations. With η Carinae unambiguously established, the report of a weak detection of γ2 Velorum (WR 11) as well as the low upper limits obtained for WR 140 and other CWBs contrast previous class...
We describe a new mechanism of dark matter production that employs a first order cosmological phase transition to suppress the dark matter relic abundance. While the mechanism can be applied generally, we study it specifically in a toy model consisting of a single real scalar field and a Dirac fermion (which will constitute the dark matter). During the cosmological phase transition the scalar...
The Galactic gamma-ray diffuse emission (GDE) is the extended radiation from the Galactic plane produced by the interaction of background cosmic rays (CRs) with ambient gas and radiation fields. Studying this radiation helps us to understand particle transport and distribution in the Galaxy. The HAWC (High Altitude Water-Cherenkov) observatory is an instrument that detects CRs and gamma-rays...
GUM is a new feature of the GAMBIT global fitting software framework, which provides a direct interface between Lagrangian level tools and GAMBIT. GUM automatically writes GAMBIT routines to compute observables and likelihoods for physics beyond the Standard Model. I will describe the structure of GUM, the tools (within GAMBIT) it is able to create interfaces to, and the observables it is able...
Nonthermal (synchrotron) X-ray spectrum is the most powerful tool to study the nature of particle (electron) acceleration in shock wave of supernova remnant (SNR). For eleven young SNRs, we measure cutoff energy parameter ($\varepsilon_0$) in the synchrotron X-ray spectrum and Bohm factor ($\eta$) by the theoretically predicted relation of $\varepsilon_0 \propto v_{\rm sh}^2 \eta^{-1}$, where...
The lightness of the three active neutrinos can be explained by the existence of an equal number of exotic heavy neutral fermions, with a mass ranging from a few MeV to around a TeV. Constraints from different sources such as direct detection, lepton flavour violation and electroweak precision observables, impose strong upper limits on their mixing of these sterile neutrinos to the active...
Microquasars, the local siblings of extragalactic quasars, are binary systems comprising a black hole of several to tens of solar masses and a companion star. By accreting matter from their companions, microquasars launch powerful winds and jets, influencing the interstellar environment around them. Steady gamma-ray emission is expected to rise from their central objects, or from interactions...
The Tibet air shower array has been observing high-energy cosmic rays and gamma rays at the altitude of 4,300 m in Tibet, China, since 1990.
Its sensitivity toward gamma rays above 10 TeV has been dramatically improved by the underground water-Cerenkov-type muon detector array added in 2014, which discriminates gamma rays from background cosmic-ray nuclei based on the number of muons in their...
It is known that cold dark matter form structures on scales much smaller than the size of typical galaxies. This clustering translates into a very large population of subhalos in the Milky Way. Analyzing Fermi-LAT data and/or using numerical simulations, several studies have investigated the possibility that among the 1525 unassociated point sources identified by the collaboration (4FGL...
We examine the collider phenomenology of two standard model extensions relevant to electroweak baryogenesis. Firstly we study the hypercharge-zero SU(2) triplet scalar extended standard model, a common component of multi-step electroweak phase transition models. Secondly, we examine a model with vector-like lepton doublets and scalar singlets. We show that both of these models are constrained...
The Sun has long been expected to be a steady gamma-ray and neutrino (>GeV) source due to constant bombardment by cosmic rays. I will discuss recent progress in studies of these solar atmospheric gamma rays with the Fermi Space Gamma-ray Telescope, and the prospects of the detecting the Sun with high-energy neutrinos. Surprisingly, the gamma-ray flux was found to be higher than the previous...
Dwarf spheroidal galaxies (dSphs) are among the most dark matter (DM) dominated objects with negligible expected astrophysical gamma-ray emission. This makes nearby dSphs ideal targets for indirect searches for a DM particle signal. The accurate knowledge of their DM content makes it possible to derive robust constraints on the velocity-weighted cross section of DM self-annihilation. In the...
The origin of high-energy of cosmic-rays (CRs) is yet not completely solved. Due to the accessibility, Galactic sources give us opportunities to investigate the ambient condition of potential sources.
The Galactic Center, on the one hand, shows a peculiar non-thermal emission. On the other hand, the crowded and emissively active vicinity makes modeling more challenging. Previous works...
Dwarf spheroidal galaxies (dSphs) are good target to search for dark matter annihilation signals with gamma-ray observations. For WIMPs lighter than $m_{\rm DM}\sim {\cal O}(10)$ GeV, the strongest constraints are obtained by Fermi’s observation of dSphs. In the near future, our accessibility to WIMPs heavier than $m_{\rm DM}\sim{\cal O} (1)$ TeV should be significantly enhanced with Cherenkov...
The identification of the gamma-ray bright BL Lac object
TXS 0506+05 with very-high-energy neutrinos detected by IceCube
triggered a large number of works on the physics implications of
neutrino production in blazar jets. Most of these works agree that
GeV - TeV gamma-rays are unlikely to be produced by the same hadronic
processes generating the IceCube neutrinos in the same emission...
Imaging atmospheric Cherenkov telescopes are uniquely suited to searching for transient astrophysical sources of both gamma-ray and optical emission. One promising class of targets for such searches are fast radio bursts (FRBs) - bright flashes of radio emission lasting just a few milliseconds and originating from outside of the Milky Way. The origin of these mysterious outbursts is unknown,...
A high-energy muon neutrino event, IceCube-170922A, was recently discovered in both spatial and temporal coincidence with a gamma-ray flare of the blazar TXS 0506+056. It has been shown, with standard one-zone models, that neutrinos can be produced in the blazar jet via hadronic interactions, but with a flux which is mostly limited by the X-ray data. In this work, we explore the neutrino...
The Fermi Large Area Telescope (LAT) has observed an excess of GeV gamma rays coming from Galactic Centre. The two main competing explanations are an unresolved population of millisecond pulsars or self-annihilating dark matter. One distinguishing feature of these two explanations is that in the annihilating dark matter case the excess is predicted to be very close to spherically symmetric....
The Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes, located on the Canary Island of La Palma, play an important role in the detection of VHE gamma rays resulting from the annihilation or decay of WIMP dark matter. Dwarf spheroidal satellite galaxies (dSphs) are among the best candidates to search for DM, having the highest known mass-to-light (M/L) ratios and being free of...
The MAGIC telescope array observes the very-high-energy gamma-ray (VHE; E > 100 GeV) sky since 2009. The system is composed of two 17-m diameter Cherenkov telescopes, sensitive to energies above 50 GeV, installed on the Canary island of La Palma. The study of gamma-ray extragalactic sources is one of the pillars of the MAGIC scientific activities. The extragalactic VHE gamma-ray sky is...
Blazar hadronic models have been developed in the past decades as an alternative to leptonic ones. In hadronic models the gamma-ray emission is associated with synchrotron emission by protons in the jet, and/or secondary leptons produced in proton-photon interactions. Together with photons, hadronic emission models predict the emission of neutrinos from blazars. Neutrinos are therefore the...
Supernova remnants (SNRs) are widely believed to be one of the main candidates for the origin of Galactic cosmic rays. Very-high-energy gamma-ray emission observed from a number of SNRs suggests that particles are indeed accelerated to high energies by shock in remnants. However, it is extremely difficult to discriminate which particles are responsible for this emission as both protons...
In the indirect dark matter (DM) detection framework, the DM particles would produce some signals by self-annihilating and creating standard model products such as γ rays, which might be detected by ground-based telescopes. Dwarf irregular galaxies represent promising targets for the search for DM as they are assumed to be dark matter dominated. These dwarf irregular galaxies are rotationally...
Some Quantum Gravity (QG) theories, aiming at unifying general relativity and quantum mechanics, predict an energy-dependent modified dispersion relation for photons in vacuum leading to a Violation of Lorentz Invariance (LIV). QG effects are expected to become sensible at a characteristic energy scale $E_{QG}$ of the order of the Planck Energy. One way of testing these theories is to monitor...
The evolution of Active Galactic Nuclei is one of most significant issues of Astrophysics, and both the spectrum and distribution of Cosmic MeV gamma Background (CMGB) are considered strongly to reflect the differences in theoretical models. However, until now only COMPTEL provided only the spectrum of CMGB measured from the wide sky area from 9years observation, although it included large...
The extragalactic neutrino background (ENB) has been measured from tens of TeV and constrained up to ultra-high energies. This work considers the unresolved source contribution to this neutrino flux produced in the jets of AGN through photomeson production considering as target the omnipresent cosmic microwave background (CMB) and extragalactic background light (EBL) radiation fields. This is...
The blazar TXS 0506+056 was recently identified as a tentative source of very high energy neutrinos. In 2017, the IceCube Observatory recorded a track-like event initiated by a neutrino with the primary energy E between 200 TeV and 7.5 PeV (90 % CL) accompanied with a bright “flare” across the electromagnetic (EM) spectrum, in particular, in the high energy (HE, E>100 MeV) domain [1]....
We study the Sommerfeld enhanced Dark Matter (DM) annihilation into gamma-ray for a class of three-loop radiative neutrino mass models with large electroweak multiplets where the DM mass is in the TeV range. We show that in this model, the DM annihilation rate becomes more prominent for larger multiplets, and it is already within reach of the currently operating Imaging Atmospheric Cherenkov...
The ASTRI Project aims at the design and development of a technologically innovative solution for small (4 m diameter) and large field of view (about 10 degrees) telescopes, of the same class of the Small-Sized Telescopes (SSTs) of the Cherenkov Telescope Array (CTA) devoted to cover the energy band up to 100 TeV and beyond. In the first phase of the project, an ASTRI prototype in a...
Various observations are revealing the widespread occurrence of fast and powerful winds in active galactic nuclei (AGN) that are distinct from relativistic jets, likely launched from accretion disks. Such winds can harbor collisionless shocks at different locations that may induce acceleration of protons and electrons and consequent nonthermal emission. We focus on the innermost regions of the...
Radio and X-ray observations of so-called radio relics indicate electron acceleration at merger shocks in galaxy clusters. These large-scale shocks are also candidate sites for ultra-high-energy cosmic ray production. Merger shocks have low Mach numbers and propagate in high beta plasmas, $\beta\gg 1$. Particle acceleration and in particular electron injection mechanisms are poorly understood...
The emission at very-high energies (VHE, >100 GeV) from gamma-ray burst (GRBs) - the most luminous explosions in the universe - remained elusive for long time. After almost a decade of efforts by current Imaging Atmospheric Cherenkov Telescopes (IACTs), within the last two years the detection of three GRBs at VHEs has been confirmed, one with the MAGIC telescopes and two with H.E.S.S. In this...
Paleo-detectors are a proposed experimental technique in which one would search for traces of recoiling nuclei in ancient minerals. Natural minerals on Earth are as old as 1 Gyr and, in
many minerals, the damage tracks left by recoiling nuclei are also preserved for time scales long compared to 1Gyr once created. Thus, even reading out relatively small target samples of order 100g,...
Axions and axion-like particles are excellent dark matter candidates, spanning a vast range of mass scales from the milli- and micro-eV for the QCD axion, to $10^{-22}\,$eV for ultralight axions, to even lighter candidates that make up the "axiverse". In some scenarios, inhomogeneities in the axion density lead to the formation of compact structures known as axion "miniclusters" and axion...
X-ray line searches are sensitive probes for many dark matter models, such as sterile neutrino dark matter in the nuMSM. I will discuss the current status of the experimental efforts, including that of the tentative signal at 3.5 keV. Then I will discuss some recent progress with NuSTAR and its prospects in the near future. Finally, I will talk about the idea of dark matter velocity...
Supernova remnants are known to accelerate cosmic rays on account of their non-thermal emission observed at radio, X-ray and gamma-ray energies. Although there are many models for the acceleration of cosmic rays in Supernova remnants, the escape of cosmic rays from these sources is yet understudied.
We use our time-dependent acceleration code RATPaC to study the acceleration of cosmic rays...
X-ray observations of nearby clusters and galaxies have reported an unexpected X-ray line around 3.5 keV. This line has received significant attention due to its possible explanation through decaying dark matter; in particular, decaying sterile neutrino models, with a sterile neutrino mass around 7 keV, provide a good fit to the available data. We use over 30 Ms of XMM-Newton blank-sky...
The hunt for Gamma-Ray-Bursts (GRBs) at very high energy (VHE) started more than 20 years ago. A hint of emission was already claimed by Milagrito from the observations of GRB 970417.
On 19 of January the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) clearly detected GRB 190114C above 0.2 TeV. This is the first highly significant detection (over 50sigma reached in the first few tens of...
The ANTARES neutrino telescope is located in the Mediterranean Sea at a depth of 2.5 km, 40 km off the Southern coast of France, and is operational since more than 10 years. The transparancy of the seawater allows for a very good resolution in the reconstruction of the incoming direction of neutrinos of all flavours. The ANTARES location in the Northern Hemisphere is optimal for the...
The existence of millicharged dark matter (mDM) can leave a measurable imprint on 21-cm cosmology through mDM-baryon scattering. However, the minimal scenario is severely constrained by existing cosmological bounds on both the fraction of dark matter that can be millicharged and the mass of mDM particles. We point out that introducing a long-range force between a millicharged subcomponent of...
We propose a multi-messenger probe of the natural parameter space of QCD axion dark matter (DM) based on observations of black hole-neutron star binary inspirals. It is suggested that a dense DM spike may grow around intermediate mass black holes. The presence of such a spike produces two unique effects: a distinct phase shift in the gravitational wave strain during the inspiral period and an...
Cosmological measurements are becoming sensitive enough to provide the first-ever measurement of the neutrino masses, and to search for completely new particles suggested by recent experiments. I will discuss the effects of these light, fast particles on the formation of large-scale cosmic structure, as well as my recent constraints on them. Then I will describe ongoing work to tackle one of...
The escape process of particles accelerated at supernova remnant (SNR) shocks is one of the poorly understood aspects of the shock acceleration theory. In this talk I will describe a phenomenological approach to study the particle escape and its impact on the gamma-ray spectrum resulting from hadronic collisions both inside and outside of a middle-aged SNR. Under the assumption that in the...
On the night of January 19, 2019, the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope detected GRB 190114C above 0.2 TeV with very high significance, recording by far the most energetic photons ever observed from a gamma-ray burst (GRB). Observations of GRBs can be used to probe an energy dependence of the speed of light in vacuo for photons (in-vacuo dispersion) as predicted by...
Using novel technology, the KM3NeT Collaboration is building a very large neutrino telescope in the Mediterranean abyss. KM3NeT comprises two detectors, ARCA and ORCA. ARCA is under construction at 3,500 m depth, about 80 km offshore the coast of Porto Palo in Sicily (Italy). It is optimsed for high-energy measurements (Tev-PeV) to perform neutrino astronomy with unprecedented sensitivity....
Recent results from IceCube regarding TXS 0506+056 suggest that it may be useful to test the hypothesis of multiple neutrino flares, where each flare is not necessarily accompanied by a corresponding gamma-ray flare. An untriggered, time-dependent, source-stacking search would be ideal for testing this hypothesis. Previous methods fit only the largest untriggered flare in the data, however a...
POLARBEAR is a ground-based experiment which is designed to measure the Cosmic Microwave Background (CMB) polarization at the James Ax Observatory at an elevation of 5,190 m in the Atacama Desert in Chile. Our science goals are for searching for the B-mode signal created by primordial gravitational waves (PGWs), as well as for characterizing the B-mode signal from gravitational lensing....
Observational constraints on gamma rays produced by the annihilation of weakly interacting massive particles around primordial black holes (PBHs) imply that these two classes of Dark Matter candidates cannot coexist. In this talk, I will show that the successful detection of one or more PBHs by radio searches (with the Square Kilometer Array) and gravitational waves searches (with LIGO/Virgo...
One of main scientific goals of Large High Altitude Air Shower Observatory (LHAASO) is to measure individual cosmic ray spectra from 30 TeV to several EeV. A quarter array of LHAASO experiment, 6 Cherenkov telescopes, one 150 m × 150 m water Cherenkov pool, about 300 muon detectors and 1300 scintillator detectors, has been completed, and they started operation in October. The combined...
Recent detection of very high energy (VHE, > 100 GeV) gamma rays from GRBs has opened a possibility to test emission mechanisms late in the afterglow phase. Synchrotron radiation from a decelerating blast wave is a widely accepted model of optical to X-ray afterglow emission from GRBs. GeV gamma rays detected by the Fermi Large Area Telescope (LAT) and the duration of which extends beyond the...
To constrain the contribution of source populations to the observed neutrino sky, we consider isotropic and anisotropic components of the diffuse neutrino data. We simulate through-going muon neutrino events by applying statistical distributions for the fluxes of extra-galactic sources and investigate the sensitivities of current (IceCube) and future (IceCube-Gen2 and KM3NeT) experiments. I...
In this talk, I show the existence of topologically stable, finite mass monopoles within Born-Infeld extension of the standard model and discuss their phenomenological and comsological implications.
We model Gamma-Ray Burst (GRB) prompt spectra in the fireball internal shock scenario. This theoretical model assumes particles to be accelerated in collisions of plasma blobs in the optically thin regime. Usually, the observed prompt emission is attributed to synchrotron emission from accelerated electrons. Additional processes like inverse Compton scattering and photon-photon annihilation...
The IceTop detector is the surface component of the IceCube Observatory. Its 81 stations of frozen water tanks are sensitive to multiple particle components of cosmic ray air showers, and can be used in coincidence with the deeply-buried in-ice component of IceCube for additional sensitivity to high-energy penetrating muons from air showers. This work focuses on measurements of cosmic rays...
Very High Energy (VHE) emission is the next frontier of exploration of the extreme physics of Gamma-Ray Bursts (GRBs). Thanks to its wide field of view the Large Area Telescope (LAT) on board of the Fermi satellite is a continuous probe of the VHE component of GRBs. A systematic search spanning the first 10 years of the Fermi-LAT data results in the detection of 186 GRBs vith energies >30MeV....
Supernova Remnants (SNRs) display a wealth of characteristics across the entire electromagnetic spectrum. These multiwavelength observations together with cosmic ray (CR) measurements make SNRs some of the first objects studied with multiple messengers. Answering some of the most compelling questions about Supernova Remnants requires not only multimessenger studies, but also sufficient...
Dark matter candidates exist over a mass range spanning greater than 70 orders of magnitude. At one end of this spectrum, Ultralight Dark Matter (ULDM) posits particles so light that their de Broglie wavelength can be as large as several kpc, giving rise to gravitational dynamics that can be very different from models with heavier candidates. Examples of such dynamics include dynamical heating...
The Telescope Array (TA) is a cosmic-ray observatory of the largest exposure in the northern hemisphere, and is operational since 2008. In this talk I will present the data analysis results using the 11-year data of TA and discuss the energy spectrum, mass composition, and arrival direction distribution of ultra-high energy cosmic rays. I will also present the status of TA extensions of TA,...
We consider a massive vector field as a model for early Universe
dark matter. Assuming that the massive vector field interacts with
the Standard Model matter very weakly and is produced
non-thermally, we study the evolution of this field in early
Universe during the radiation dominated epoch. We show that this
field may be naturally created with the equation of state of
radiation...
The H.E.S.S. Imaging Air Cherenkov Telescope system is, due to its fast reaction time and its comparably low energy threshold, very well suited to perform follow-up observations of detections at other wavelengths or other messengers like high-energy neutrinos and gravitational waves. These advantages are utilized optimally via a fully automatized system reacting to alerts from various partner...
The implications of requiring the necessary generation of the baryon asymmetry via the decay of heavy sterile neutrinos on the parameter space of the Inverse Seesaw (ISS) and Linear Seesaw (LSS) is explored. Often in such low-scale seesaw scenarios a natural mass degeneracy occurs resulting in a relatively small mass splittings amongst sterile neutrinos, allowing for a resonant enhancement in...
We fit ultrahigh-energy cosmic ray spectrum and composition data from the Pierre Auger Observatory using two populations of astrophysical sources. One population, accelerating dominantly protons, follows typical cosmological evolution similar to luminous astrophysical sources; while another, mostly nearby, population of astrophysical sources accelerate light-to-heavy nuclei. We compute...
Pulsar Wind Nebulae (PWNe) constitute the largest class of identified Galactic sources of TeV gamma-rays, as revealed by the Galactic Plane Survey with the HESS telescopes. This survey allowed a systematic study of a large number of PWNe in TeV gamma-rays, and revealed properties that could only be hinted at previously. In particular, there is a weak but significant trend for the gamma-ray...
A coherently oscillating axion field is one of the dark matter candidate. It is known that the propagation of photons in the presence of axion dark matter is governed by the Mathieu equation. It is also known that axion and photon can mix with each other in the presence of magnetic fields.
Thus, we investigated what happens to the system where the axion dark matter and magnetic fields...
It has been argued that oscillatory features from spectator fields in the primordial power spectrum could be a probe of alternatives to inflation. In view of the future prospects for detecting oscillatory signals in the Cosmic Microwave Background, it is important to clarify whether those associated with alternative scenarios could be mimicked by non-trivially interacting spectator fields in...
Extensive Air Shower (EAS) arrays are survey instruments able to monitor continuously all the overhead sky.
Their wide field of view (about 2 sr) is ideal to complement directional detectors by performing unbiased sky surveys, by monitoring variable or flaring sources, such as AGNs, and to discover transients or explosive events (GRBs).
With an energy threshold in the 100 GeV range EAS...
HESS J1825-137 is the archetypal example of energy-dependent morphology within a pulsar wind nebula. In a deep analysis with ten years of Fermi-LAT data, we measure continued energy dependence into the GeV regime. Combining GeV and TeV data yields new insights into the evolutionary history of the system. We use a multi-zone model to reproduce simultaneously the spectral and morphological...
Now that WIMP dark matter searches are rapidly approaching the neutrino floor, there has been a resurgence in interest towards detectors with directional sensitivity. A large enough detector with such a capability introduces the possibility of identifying a clear signature of dark matter particles with signals weaker than the neutrino background, all the while fulfilling a dual purpose in...
In this talk I will dicuss the production of multiple messengers in multi-collision models of gamma-ray bursts (GRBs). In the internal shock model for GRBs, their prompt emission is generated by collisions of regions with different Lorentz factors in the GRB jet (shells). Multi-collision models take the full dynamic of the jet into account generating a range of collisions happening at...
Ground-based, wide field of view instrumentation in gamma-ray astronomy such as HAWC and LHAASO is currently limited to the northern hemisphere and hence, lack sensitivity to our Galactic Center and the rest of the southern sky. A Gamma-ray Observatory comprising an array with a high fill factor (> 70 %) of primarily modular and scalable Water Cherenkov Detector (WCD) units in the Southern...
We study the possibility of reheating the universe in its early stages through the evaporation of
Primordial Black Holes (PBHs) that are formed due to the collapse of the inhomogeneities that
were generated during inflation. By using the current results of the baryon-photon ratio obtained
from BBN and CMB observations, we impose constraints on the spectral index of perturbations on
those...
Vela X is a nearby pulsar wind nebula (PWN) powered by a $\sim 10^4$ year old pulsar. Modeling of the spectral energy distribution of the Vela X PWN has shown that accelerated electrons have largely escaped from the confinement, which is likely due to the disruption of the initially confined PWN by the supernova remnant (SNR) reverse shock. The escaped electrons propagate to the earth and...
Andes Large area PArticle detector for Cosmic ray and Astronomy (ALPACA) is a new air shower experiment to be constructed near the Chacaltaya mountain in Bolivia at altitude of 4740 m. A conventional surface array with 401 scintillation counters covers 83,000 m$^2$ to detect cosmic rays and cosmic gamma rays above 10TeV. Total 5400 m$^2$ of water Cherenkov muon detector is constructed 2.2 m...
The case for cosmic ray nuclei at the highest energies has become stronger with recent composition results from the Pierre Auger Observatory and Telescope Array. To understand the origin of these nuclei we need more reliable models of their interactions with photons. The currently used photomeson treatment underestimates the nuclear disruption and overestimates the photoproduction of pions...
The discovery of gravitational waves from binary black hole mergers has renewed interest in primordial black holes forming a part of the dark matter density of our Universe. Various tests have been proposed to test this hypothesis. One of the cleanest tests is the lensing of fast radio bursts. In this situation, the presence of a compact object near the line of sight produces two images of the...
We revisit the SM calculation of Neff, motivated by results discrepant with the canonical value of $N_{\rm eff}=3.044$ (Gariazzo, S. et al., 2019). We show that the discrepancy (which gave $N_{\rm eff}=3.052$ (Grohs, E. et al. 2015)) stems from a misunderstanding of the interactions that take place in the plasma at finite temperature.
After clarifying common pitfalls, we follow this up...
Recently, the HAWC experiment revealed an extended multi-TeV emission (so-called TeV halo) around several tens of parsecs around Geminga, implying an inefficient diffusion zone in that region. On the other hand, the TeV-emitting electrons are supposed to give rise to X-ray as well via synchrotron radiation in the ISM magnetic field. We perform a X-ray analysis on the region around Geminga but...
High energy cosmic rays can interact in our atmosphere with energies up to 10$^{20}$ eV. At these extreme energies, the high energy hadronic interaction models are not able to describe the observed properties in air showers. In this presentation, we will present a comparison of observations from the Pierre Auger Observatory and expectations according to high energy hadronic interaction models.
Carpet is an air-shower array at Baksan, Russia, equipped with a large-area muon detector, which makes it possible to separate primary photons from hadrons. We report results of the search for primary photons with energies E>300 TeV, including diffuse and point-source fluxes or limits, in particular for gamma rays associated with the IceCube neutrino flux. Final data obtained with Carpet-2...
With an estimated age of approximately $3\cdot10^5$ years and at the distance of 250 pc, Geminga (PSRJ0633+17) is an old nearby pulsar and the prototype of the gamma-ray loud and radio-quiet pulsars.
The Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope has continuously observed Geminga over its eleven years of operation characterizing its doubly peaked pulsed emission...
The picture painted by the standard model is elegant, but incomplete: It predicts neutrinos to be massless. Although it is straightforward to introduce neutrino masses, there is a huge number of possibilities and we do not know which one is realized in nature. Thus it is important to build a framework to distinguish models. I will discuss a new way to systematically discuss phenomenology of...
Though the exact nature of neutrino masses is presently a mystery, there exists a variety of experimental avenues for siphoning information about them. Of these, we are interested in what can be gleaned from precision measurements of the Higgsstrahlung ($e^+ e^- \to Zh$) cross section, a route that will become available with the next generation of lepton colliders. Generically, $\sigma(e^+ e^-...
We present precision high statistics measurements of primary cosmic ray protons, helium, carbon and oxygen fluxes by Alpha Magnetic Spectrometer in the rigidity range from 2 GV to 3 TV. These measurements are based on 1 billion of protons, 125 million of Helium, 14 million of Carbon and 12 million of Oxygen nuclei collected by AMS during the first 7 years of operation aboard the International...
The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus on a narrower range of masses: the natural scenario where dark matter originates from thermal contact with familiar matter in the early Universe requires the DM mass to lie within about an MeV to 100 TeV. Considerable...
Blazars are known for their variability on a wide range of timescales at all wavelengths. Their classification into flat spectrum radio quasars, low-, intermediate- or high-frequency-peaked BL Lac (FSRQ, LBL, IBL, HBL, respectively) is based on broadband spectral characteristics that do not account for possible different activity states of the source. Recently, it was proposed that blazars...
The XENON program aims at finding direct evidence for the existence of Weakly Interacting Massive Particles (WIMPs) using the dual-phase xenon time projection chamber technology. The XENON1T experiment was the first ton-scale detector searching for Dark Matter via nuclear recoils and constrained the Spin Independent interaction to the world's best limit. To further increase the WIMP discovery...
The current generation of Cherenkov telescopes have identified a population of BL Lacertae objects characterized by a hard spectrum in the TeV band. The peak of their gamma-ray SED component is located beyond 100 GeV and up to several TeV, and their synchrotron peak is located beyond 1 keV and often in the hard-X-ray band. These peak frequencies are extreme within the blazar population, at the...
We present a set of minimal Dirac neutrino mass models and discuss their cosmological consequences. Specifically, such models generate a neutrino mass at tree level and can have a multiple gravitational wave signature through primordial phase transition(s), can explain the asymmetry between matter and antimatter via neutrinogenesis and accommodate a dark matter candidate in dark glueballs or...
A future lepton collider is expected to be able to measure the cross section of the Higgsstrahlung process to sub-percent level precision. In this talk, it is argued that this will provide an opportunity to indirectly probe models which incorporate the seesaw mechanism to generate small Majorana masses for neutrinos. The expected corrections to selected Standard-Model observables, which are...
The fluxes and flux ratios of charged elementary particles in cosmic rays are presented in the absolute rigidity range from 1 up to 2000 GV. Of particular interest is the energy dependance of the positron flux, which clearly shows the existence of the new source of high energy cosmic ray positrons. In the absolute rigidity range ∼60 to ∼500 GV, the antiproton, proton, and positron fluxes are...
Relativistic magnetic reconnection, a process which converts magnetic energy to particle acceleration, is an ideal mechanism for the multi-wavelength spectral and temporal variability observed in blazar jets. By coupling recent two-dimensional particle-in-cell simulations of relativistic reconnection with a time-dependent radiative transfer model, we compute the non-thermal emission from a...
Currently finalizing its design and beginning its construction, the General Anti Particle Spectrometer (GAPS) is a planned balloon-borne cosmic-ray experiment scheduled for a long duration balloon flight from McMurdo Station in the Antarctic. Its primary science goal is the search for light antinuclei in cosmic rays at energies in the region below 0.25 GeV/n. This energy region is especially...
Recently, some unexpected phenomena in various B meson decays are being observed in several experiments. Few of the observables are branching ratio of $B_s→φμ^+ μ^-$ decay, angular observable P_5^' in $B→K^* μ^+ μ^-$ decay, lepton flavour non-universality parameters $R_{K(^*)}$,$R_{D(^*)}$ etc. The fact that these observables show significant deviation around 3σ from their standard model (SM)...
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double-beta decay (0νββ) that has been able to reach the one-ton scale. The detector, located at the Laboratori Nazionali del Gran Sasso in Italy, consists of an array of 988 TeO$_{2}$ crystals arranged in a compact cylindrical structure of 19 towers. The construction of...
The PandaX experiment uses liquid xenon as the target material to perform the dark matter direct detection at China Jinping Underground Laboratory. Recently, the PandaX-II experiment with 580 kg liquid xenon in the sensitive volume just finished the data-taking and the total exposure is around 140 ton-day. Meanwhile, the PandaX collaboration is planing for the next generation multi-ton liquid...
The spectral properties of the cosmic-ray (CR) spectrum in the interstellar medium can be understood by comparing the results of gamma-ray observation with the direct local CR measurements. Among the best candidates for such studies are giant molecular clouds (GMCs) of the Gould Belt star formation region, since these clouds are usually located outside of the Galactic plane where associated...
Most of the existing works on extragalactic TeV gamma-ray propagation account for only adiabatic losses and primary gamma-ray absorption due to pair production on extragalactic background light (EBL) photons, i.e. assuming the “absorption-only model” (AOM). However, the observable spectra of some active galactic nuclei (AGN) reveal a tentative excess in photon counts with respect to the AOM in...
LUX (Large Underground Xenon) was a dark matter direct detection experiment which used a two-phase xenon Time Projection Chamber and operated at the Sanford Underground Research Facility (SURF) in South Dakota from 2012 to late 2016. It previously set world-leading limits on spin-independent cross-section for Weakly Interacting Massive Particle (WIMP) dark matter. Recent LUX analyses are...
A successful electro-weak baryongenesis calls for a strong first order electro-weak phase transition (SFOEWPT), which is unavailable in the Standard Model (SM). Some degree of modification on Higgs potential at electro-weak temperature is required to develop an energy barrier, and the property of Higgs at zero temperature is also changed accordingly. In this work we study the realization of...
Recent global fit results to the 3+1 sterile neutrino model indicate a preference for an eV-scale sterile state. The IceCube Neutrino Observatory is uniquely positioned to search for the signature of this state using matter enhanced oscillations of atmospheric muon neutrinos passing through the core of the Earth. We present the results from two such searches using eight years of IceCube data....
The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for gamma-ray astronomy and will consist of Imaging Atmospheric Cherenkov Telescopes (IACTs) distributed over two sites, one in the northern and one in the southern hemisphere. CTA will detect gamma rays from 20 GeV to 300 TeV by means of three different telescope sizes. The sub-arrays of four Large Size...
An accurate estimate of the interstellar gas density distribution is crucial to understanding the interstellar medium (ISM) and Galactic cosmic rays (CRs). However, a significant amount of gas not traced properly by standard radio line surveys (``dark gas") has been preventing accurate measurement of the total neutral gas column density and CR intensity. To overcome this difficulty, we...
Large Extra Dimensions have been proposed as a compelling solution to the hierarchy problem, with a ‘true’ Planck scale that can be as low as a few TeV. In such scenarios, high-energy collisions can lead to the creation of microscopic black holes, which have been sought in cosmic ray interactions and at colliders. Future neutrino telescopes such as IceCube Gen2, km3Net, RNO and GVD have the...
We perform a comprehensive survey of the phase structure of the Next-to-Minimal Supersymmetric Standard Model (NMSSM), focusing on the first order phase transitions. Strong first order phase transitions are required for successful electroweak baryogenesis explanations of the observed baryon asymmetry of the universe and can lead to gravitational wave signals. The NMSSM is one of the most...
Creative ideas for extending the reach of large scale dark matter direct detection experiments to low mass WIMPs include exploiting inelastic detection channels. Two examples are the Migdal effect (atomic ionization) and photon bremsstrahlung from the recoiling nucleus. We calculated these effects for a variety of momentum- and spin-dependent dark matter interactions described by...
Positron annihilation has been observed toward the center of the Galaxy for around 50 years, via the detection of gamma-rays produced in positron-electron co-annihilation. However, the origin of these positrons remains uncertain, and proposed sources include the annihilation or decay of Dark Matter. Constraining the injection energy of the positrons allows us to constrain the origin of the...
We propose a new concept of gamma-ray telescope called MAST [1] (an abbreviation from “massive Argon space telescope”) for the energy range of 100 MeV – 1 TeV based on the liquid Argon time projection chamber (LAr TPC) technique. The LAr TPC technique has many important advantages, including simplicity, scalability and cost-effectiveness, at the same time allowing to obtain good spatial (and...
We explore in detail the possibility that gravitational wave signals from binary inspirals are affected by a new force that couples only to dark matter particles. We discuss the impact of both the new force acting between the binary partners as well as radiation of the force carrier. We identify numerous constraints on any such scenario, ultimately concluding that observable effects on the...
The true nature of dark energy remains largely unknown. In search of an alternative to the cosmological constant, several classes of theoretical models utilise scalar fields in an attempt to achieve accelerated expansion of the universe. On the experimental front, upcoming large scale structure surveys, such as Euclid and SKA, will provide high precision power spectrum data on a wide range of...
The LUX-ZEPLIN (LZ) experiment is a direct dark matter search experiment that is under construction at the Sanford Underground Research Facility (SURF) in South Dakota (USA). It is based on dual-phase xenon technology and contains 7 tonnes of active liquid xenon in the time projection chamber (TPC). The active xenon volume is surrounded by the instrumented xenon skin, a liquid organic...
The Cherenkov Telescope Array (CTA) is the next-generation observatory for ground-based gamma-ray astronomy, providing unprecedented sensitivity and angular resolution in an energy range from 20 GeV to more than 300 TeV.
Active Galactic Nuclei (AGN) emit variable radiation across the entire electromagnetic spectrum up to multi-TeV energies. CTA’s observations of AGNs will allow probing...
White dwarfs (WD) effectively act as high-gain amplifiers for relatively small energy deposits within their volume via their instability to thermal runaway that culminates in a supernova. I will detail how a contamination of WD by $\mathcal{O}(1)$-charged massive particles (CHAMPs) could trigger the instability, leading to the destruction of old WD. Such a CHAMP contamination can either be...
Upcoming data from experiments like the LSST, Euclid or the SKA will help to greatly advance the precision of cosmological parameter estimation in the next decade. However, the yet unknown nature of Dark Matter and Dark Energy hint for the need to extend the current standard model of cosmology and particle physics. Non-standard scenarios can leave imprints on cosmological, astrophysical as...
Neutron star mergers are unique multi-messenger laboratories of accretion, ejection, and r-process nucleosynthesis. Theoretically, however, our current understanding of such events is limited, especially of magnetic effects, such as the role the post-merger magnetic field geometry has on the evolution of merger remnant accretion disks. Through the use of 3D general relativistic...
DarkSide-20k experiment utilizes 20 tonnes of 39Ar-depleted argon as fiducial mass in a dual-phase Time Projection Chamber (TPC) to search for dark matter signals. In this talk, I will present the development of Silicon Photomultipliers (SiPMs) based photosensors, specifically for liquid argon detector. I will also present the design and prototyping of the inner detector, with an emphasis on...
Photons may convert to axion-like particles (ALPs) in external magnetic fields. Under certain conditions, this effect should result in irregular features in observed spectra of astrophysical sources. Lack of such irregularities in particular spectra was used to constrain ALP parameters, with two most popular sources being the radio galaxy NGC 1275 and the blazar PKS 2155-304. The effect and,...
Even with several thousand Fermi-LAT blazar detections, the high-energy jet emission mechanism is poorly understood. Although popular models point towards leptonic processes, the recent possible neutrino association with a γ-ray flare challenges our understanding of these processes implicating a hadronic contribution to the high energy emission of blazar jets. I will discuss our recent efforts...
The detection of the first neutron star merger, GW170817, heralded the dawn of a new era in multi-messenger astronomy. Observations of radio emission from the resulting afterglow helped constrain merger parameters including the jet opening angle, the energetics of the merger and the circum-merger density. However, these observations alone were insufficient to distinguish between two competing...
Minkowski Functionals are a set of descriptors, which can be used to describe the morphological structures of a map. Unlike the power spectrum, they intrinsically contain higher order correlations information. CMB weak lensing, a powerful probe of the early universe and cosmological parameters. Imprinting projective information of large-scale structures all the way back to the last scattering...
I will present a review of experiment and theory in these areas based on our 30 Phys. Rev. Lett., Phys. Rev. D, A and Nature-Physics papers published in 2018-2019.
A. Zhitnitsy et al developed Axion Quark Nuggets (AQN) model which can explain both bariogenesis and dark matter within the Standard Model plus axion. We have suggested methods to detect axions produced by AQN passing through...
The Large Volume Detector, hosted in the INFN Laboratori Nazionali del Gran Sasso, is triggered by atmospheric height energy muons ($E_\mu$>1 TeV), which are produced in the decay of short-lived charged mesons in the extensive air showers, at a rate of $\sim 0.1$~Hz.
The data collected over almost a quarter of century (1994-2017), the longest ever exploited by a single instrument, allows for...
Galaxy clusters are known to be reservoirs of Cosmic Rays (CRs), as inferred from theoretical calculations or detection of CR-derived observables. CR acceleration in clusters is mostly attributed to the dynamical activity that produces shocks. Shocks in clusters emerge out of merger or accretion, but which one is more effective in producing CRs? at which dynamical phase? and why? To this aim,...
We present a new self-consistent method for incorporating dark matter annihilation feedback (DMAF) in cosmological N-body simulations. The power generated by DMAF is evaluated at each dark matter (DM) particle which allows for flexible energy injection into the surrounding gas based on the specific DM annihilation model under consideration. Adaptive, individual time steps for gas and DM...
We present the results of the first-ever search for gravitational waves from a remnant of binary neutron star merger GW170817 using convolutional neural networks (CNNs). Analyzing one week of data after GW170817 for signals lasting about one hour did not return any viable candidates. We describe the search pipeline in detail, showing that the CNNs are used to trigger possible interesting...
Some Quantum Gravity (QG) models developed to unify general relativity and quantum mechanics predict an energy-dependent speed of light in vacuum which breaks Lorentz Symmetry. Such effects are expected to contribute at a characteristic energy scale E_QG of the order of the Planck Energy. These models are tested by monitoring energy-dependent time-lags for photons emitted by distant, highly...
We study gravitational waves generated by binary systems within an extension of General Relativity which is described by the addition of quadratic in curvature tensor terms to the Einstein-Hilbert action. Treating quadratic gravity as an effective theory valid in the low energy/curvature regime, we argue that reliable calculations can be performed in the early inspiral phase, and furthermore,...
The standard model of cosmology is based on two unknown dark components that are generally assumed to be non-interacting. Relaxing this assumption opens a class of interacting models that have recently seen renewed interest in light of cosmological tensions. In this talk, we discuss some of these models and present an analysis of recent datasets investigating whether there is evidence for an...
Detection schemes for the QCD axions and other axion-like particles (including axionic Dark Matter) in light-shining-through-a-wall (LSW) experiments are based on the conversion of these particles into photons in a magnetic field. An alternative scheme may involve the detection via a resonant atomic or molecular transition induced by resonant axion absorption. The signal obtained in this...
The contribution of unresolved gamma-ray point sources to the
extragalactic gamma-ray background has been recently measured through
analyses employing the statistical properties of observed gamma-ray counts.
The contribution from each
specific source class to the source-count distribution, such as blazars,
misaligned Active Galactic Nuclei, or Star Forming Galaxies is affected by
...
Gamma-ray binary systems are nowadays a complex class of compact
binary systems displaying variable gamma-ray emission. This class
includes different types of objects, which may host two stars or a
star and a compact object. Depending on the specific realization, the
physical scenario for production of gamma rays may differ considerably
between some gamma-ray binary systems. In this talk,...
