2,959 research outputs found
Slow theory : taking time over transnational democratic representation
The possibility for transnational democratic representation is a huge topic. This article is restricted to exploring two unconventional aspects. The first concerns 'the representative claim', extending one critical part of previous analysis of the assessment of such claims, especially by largely unelected transnational actors. The second, which strongly conditions the account of the first, concerns ‘slow theory’ as the way to approach building democratic models and, in particular, to approach transnational democratic representation
Neutrinos from active black holes, sources of ultra high energy cosmic rays
A correlation between the highest energy Cosmic Rays (above ~ EeV) and the
distribution of active galactic nuclei (AGN) gives rise to a prediction of
neutrino production in the same sources. In this paper, we present a detailed
AGN model, predicting neutrino production near the foot of the jet, where the
photon fields from the disk and synchrotron radiation from the jet itself
create high optical depths for proton-photon interactions. The protons escape
from later shocks where the emission region is optically thin for proton-photon
interactions. Consequently, Cosmic Rays are predicted to come from FR-I
galaxies, independent of the orientation of the source. Neutrinos, on the other
hand, are only observable from sources directing their jet towards Earth, i.e.
flat spectrum radio sources and in particular BL Lac type objects, due to the
strongly boosted neutrino emission.Comment: Accepted for publication in Astroparticle Physics; 30 pages, 8
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The diffuse neutrino flux from FR-II radio galaxies and blazars: A source property based estimate
Water and ice Cherenkov telescopes of the present and future aim for the
detection of a neutrino signal from extraterrestrial sources at energies E>PeV.
Some of the most promising extragalactic sources are Active Galactic Nuclei
(AGN). In this paper, the neutrino flux from two kinds of AGN sources will be
estimated assuming photohadronic interactions in the jet of the AGN. The first
analyzed sample contains FR-II radio galaxies while the second AGN type
examined are blazars. The result is highly dependent on the proton's index of
the energy spectrum. To normalize the spectrum, the connection between neutrino
and disk luminosity will be used by applying the jet-disk symbiosis model from
Falcke and Biermann (1995). The maximum proton energy and thus, also the
maximum neutrino energy of the source is connected to its disk luminosity,
which was shown by Lovelace (1976) and was confirmed by Falcke et al. (1995).Comment: 24 pages, 14 figures, to be published in Astroparticle Physic
Neutrinos from photo-hadronic interactions in Pks2155-304
The high-peaked BL Lac object Pks2155-304 shows high variability at
multiwavelengths, i.e. from optical up to TeV energies. A giant flare of around
1 hour at X-ray and TeV energies was observed in 2006. In this context, it is
essential to understand the physical processes in terms of the primary spectrum
and the radiation emitted, since high-energy emission can arise in both
leptonic and hadronic processes. In this contribution, we investigate the
possibility of neutrino production in photo-hadronic interactions. In
particular, we predict a direct correlation between optical and TeV energies at
sufficiently high optical radiation fields. We show that in the blazar
Pks2155-304, the optical emission in the low-state is sufficient to lead to
photo-hadronic interactions and therefore to the production of high-energy
photons.Comment: contribution to RICAP 2009 and ICRC 2009 - both papers are combined
in one draft. 11 pages, 3 figure
The Origin of Galactic Cosmic Rays
Motivated by recent measurements of the major components of the cosmic
radiation around 10 TeV/nucleon and above, we discuss the phenomenology of a
model in which there are two distinct kinds of cosmic ray accelerators in the
galaxy. Comparison of the spectra of hydrogen and helium up to 100 TeV per
nucleon suggests that these two elements do not have the same spectrum of
magnetic rigidity over this entire region and that these two dominant elements
therefore receive contributions from different sources.Comment: To be published in Physical Review D, 13 pages, with 3 figures,
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The Art of Hope: Imagining Another World in a World That Breaks Our Hearts
There is something almost surreal about Christianity. At its heart is a string of incredible claims — a God who becomes human; a crucified God who is raised from the dead; a cosmic Creator who knows everything about us and yet loves us, forgives us, and promises to wipe away every tear. Is it any wonder, then, that the Church has been an incubator of the imagination, a wellspring for the arts? If orthodoxy is generous because it has something to offer the world, one of those gifts is an ability to imagine the world otherwise. The Chalcedonian orthodoxy that dares to imagine the mystery of the God-man is the orthodoxy that underwrites an entire artistic tradition that speaks to human hungers. This lecture will consider how and why the Spirit speaks to us in songs and poems, painting portraits of a world we couldn’t otherwise imagine — and why the arts are a conduit of hope in a culture of despair
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