3,426 research outputs found
Multimessenger Potential of the Radio Neutrino Observatory in Greenland
The Radio Neutrino Observatory in Greenland (RNO-G) is the only ultrahigh
energy (UHE, ~PeV) neutrino monitor of the Northern sky and will
soon be the world's most sensitive high-uptime detector of UHE neutrinos.
Because of this, RNO-G represents an important piece of the multimessenger
landscape over the next decade. In this talk, we will highlight RNO-G's
multimessenger capabilities and its potential to provide key information in the
search for the most extreme astrophysical accelerators. In particular, we will
highlight opportunities enabled by RNO-G's unique field-of-view, its potential
to constrain the sources of UHE cosmic rays, and its complementarity with
IceCube at lower energies
Probing extreme astrophysical accelerators through neutrino anisotropy
We present the extent to which anisotropies in the ultrahigh energy neutrino
sky can probe the distribution of extreme astrophysical accelerators in the
universe. In this talk, we discuss the origin of an anisotropic neutrino sky
and show how observers can use this anisotropy to measure the evolution of
ultrahigh energy neutrino sources - and therefore, the sources of ultrahigh
energy cosmic rays - for the very first time
Constraints on the hosts of UHECR accelerators
Interactions of ultrahigh energy cosmic rays in the surroundings of their
accelerators can naturally explain the observed spectrum and composition of
UHECRs, including the abundance of protons below the ankle. We show that
astrophysical properties of the UHECR source environment such as the
temperature, size, and magnetic field can be constrained by UHECR and neutrino
data. Applying this to candidate sources with a simple structure shows that
starburst galaxies are consistent with these constraints, but galaxy clusters
may be in tension with them. For multi-component systems like AGNs and GRBs the
results are indicative but customized analysis is needed for definitive
conclusions
Communication Between Process and Structure: Modelling and Simulating Message Reference Networks with COM/TE
Focusing on observable message signs and referencing structures, communication processes can be described and analysed as message reference networks which are characterized by dynamic pattern evolution. Computational simulation provides a way of obtaining insights into the factors driving such processes. Our paper describes a theoretical framework for communication-oriented modelling — the COM approach — that is centred around the notion of social visibility as a reputation mechanism. The approach contrasts with agent-based social networks on the one hand, and with bibliometric document networks on the other. In introducing our simulation environment COM/TE, typical properties of message reference networks are discussed in terms of a case study which deals with the impact of different media and styles of communication on emergent patterns of social visibility.Communication, Communication-Oriented Modelling, Message Sign, Dynamic Networks, Bottom-up Approach, Temporality, Social Visibility, Reputation, Socionics
On fractional Choquard equations
We investigate a class of nonlinear Schrodinger equations with a generalized
Choquard nonlinearity and fractional diffusion. We obtain regularity,
existence, nonexistence, symmetry as well as decays properties.Comment: revised version, 22 page
A Peters cycle at the end of the cosmic ray spectrum?
We investigate the degree to which current ultrahigh energy cosmic ray
observations above the ankle support a common maximum rigidity for all nuclei,
often called a Peters cycle, over alternative scenarios for the cosmic ray
spectra escaping sources. We show that a Peters cycle is not generally
supported by the data when compared with these alternatives. We explore the
observational signatures of non-Peters cycle scenarios, and the opportunities
to explore both ultrahigh energy cosmic ray source conditions, as well as,
physics beyond the Standard model they present
Data-driven analysis for understanding ultrahigh energy cosmic ray source spectra
One of the most challenging open questions regarding the origin of ultrahigh
energy cosmic rays (UHECRs) deals with the shape of the source emission
spectra. A commonly-used simplifying assumption is that the source spectra of
the highest energy cosmic rays trace a Peters cycle, in which the maximum
cosmic-ray energy scales linearly with , i.e., with the charge of the UHECR
in units of the proton charge. However, this would only be a natural assumption
for models in which UHECRs escape the acceleration region without suffering
significant energy losses. In most cases, however, UHECRs interact in the
acceleration region and/or in the source environment changing the shape of the
source emission spectra. Energy losses are typically parameterized in terms of
and the UHECR baryon number , and therefore one would expect the source
emission spectra to be a function of both and . Taking a pragmatic
approach, we investigate whether existing data favor any region of the
parameter space. Using data from the Pierre Auger Observatory, we carry out a
maximum likelihood analysis of the observed spectrum and nuclear composition to
shape the source emission spectra for the various particle species. We also
study the impact of possible systematic uncertainties driven by hadronic models
describing interactions in the atmosphere
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