I will discuss some of the open problems related to the origin of Galactic cosmic rays, in terms of both acceleration and transport.
Operating nearly flawlessly for nine years from October 2015, the Calorimetric Electron Telescope (CALET) has been measuring the properties of the cosmic radiation. CALET was designed to achieve the primary objectives of measuring the spectra of electrons/positrons through the TeV energy decade to search for nearby sources and/or signatures of dark matter processes and measure the spectra of...
The space-based DAMPE (DArk Matter Particle Explorer) detector has been taking data since its successful launch in December 2015. Its main scientific goals include the indirect search for dark matter signatures in the cosmic electron and gamma-ray spectra, the measurements of galactic cosmic ray fluxes from tens of GeV up to hundreds of TeV and high energy gamma ray astronomy above a few...
I will discuss possible origins of spectral features observed at low and high energies.
The GRAPES-3 experiment, situated in Ooty, India, uses a dense array of plastic scintillator detectors and a large-area tracking muon detector to measure all charged particles and the muonic components of cosmic ray showers, respectively. The experiment has measured the cosmic ray proton spectrum in the energy range of 50 TeV to 1.3 PeV, and the relative proton composition was determined using...
The HAWC Gamma-Ray Observatory is an extensive air-shower detector array located at 4100 m a.s.l. on the slopes of Volcán Sierra Negra at 19°N in the state of Puebla, Mexico. While HAWC is designed to study the sky in gamma-rays between 500 GeV and 100 TeV, it is also sensitive to showers from primary cosmic rays in the TeV to to multi-PeV energy range. We report on the latest measurements of...
In the last decade or so, several young stellar clusters in pour Galaxy have been associated with diffuse gamma-ray sources detected from GeV to multi-TeV enegy band, supporting the idea that efficient particle acceleration is taking place in those objects. Particle acceleration may occur through different mechanisms: i) at the termination shock of stellar winds produced by massive stars, ii)...
The origin of cosmic rays has been a century-old question. As it is challenging to utilize the directional information of cosmic rays to learn about their origin, observing the gamma rays and neutrinos generated by the interactions of cosmic rays around the source regions has been considered to be the best way to study the origin of cosmic rays. In the last decades, there have been remarkable...
Cosmic rays are ultrarelativistic particles that permeate the Milky Way, propagating through the Galactic turbulent magnetic fields. The mechanisms under which these particles increase their energy can be reasonably described by current theories of acceleration and propagation of cosmic rays. There are, however, still many open questions as to how to reach petaelectronvolt (PeV) energies, the...
Below the geographic South Pole, the IceCube project has transformed one cubic kilometer of natural Antarctic ice into a neutrino detector. IceCube detects more than 100,000 neutrinos per year in the GeV to 10 PeV energy range. Among those, we have isolated a flux of high-energy neutrinos originating beyond our Galaxy, with an energy flux that is comparable to that of the extragalactic...
The next Galactic core-collapse supernova will offer an unparalleled opportunity to probe the explosive rebirth of massive star to compact object across all cosmic messengers. In this talk, I will outline what multi-messenger observations can tell us about stellar evolution, the nascent compact object population, and fundamental physics. I will discuss the current prospects for detection of...
Recent multi-messenger observations of the Galactic plane have revealed new classes of gamma-ray emitters at energies reaching into the multi-tens of TeV range, challenging our previous understanding based on lower-energy data. These unexpected sources include TeV halos—extended gamma-ray emissions around isolated pulsars that cannot be explained as traditional pulsar wind nebulae—as well as...
I will discuss some recent work on the interaction of cosmic rays with turbulent, diffuse, multiphase gas in the interstellar medium and beyond. Our work focuses on spatial scales which are typically not resolved by global simulations but are large compared to kinetic scales, and to the cosmic ray mean free path, so the fluid approximation holds. Phenomena at these scales are potentially...
First-principles plasma simulations have been pivotal in helping developing a theory of ion and electron acceleration at shocks, and in particular in SNRs. I discuss what we have learned about particle acceleration efficiency, spectra, and maximum energy, and contrast these results with multi-wavelength emission from SNRs. Despite compelling evidence of hadron acceleration in these sources,...
We present two models of CR transport in the Galaxy. One with isotropic diffusion, and another one with anisotropic diffusion, where CRs are propagated in Galactic magnetic field models. In both models, CRs are injected at discrete transient sources in the disc. We calculate the corresponding diffuse Galactic gamma-ray emissions. We find that the emission at >~ 100 TeV is very clumpy, and does...
The IceCube Neutrino Observatory has recently reported strong evidence for neutrino emission from the Galactic plane. The signal is consistent with model predictions of diffuse emission from cosmic ray propagation in the interstellar medium. However, due to IceCube's limited potential of identifying individual neutrino sources, it is also feasible that unresolved Galactic sources could...
Observations by AMS-02 on the International Space Station have tentatively detected approximately 10 events that are consistent with antihelium nuclei. Such a detection would be of significant theoretical interest due to the difficulty in producing any detectable antihelium flux through standard model interactions. In this talk, I will discuss the state of these observations, the state of...
