1,021 research outputs found
Extensive air showers with TeV-scale quantum gravity
One of the possible consequences of the existence of extra degrees of freedom
beyond the electroweak scale is the increase of neutrino-nucleon cross sections
() beyond Standard Model predictions. At ultra-high energies
this may allow the existence of neutrino-initiated extensive air showers. In
this paper, we examine the most relevant observables of such showers. Our
analysis indicates that the future Pierre Auger Observatory could be
potentially powerful in probing models with large compact dimensions.Comment: 7 pages revtex, 5 eps fig
Particle Astrophysics and Cosmology: Cosmic Laboratories for New Physics (Summary of the Snowmass 2001 P4 Working Group)
The past few years have seen dramatic breakthroughs and spectacular and
puzzling discoveries in astrophysics and cosmology. In many cases, the new
observations can only be explained with the introduction of new fundamental
physics. Here we summarize some of these recent advances. We then describe
several problem in astrophysics and cosmology, ripe for major advances, whose
resolution will likely require new physics.Comment: 27 pages, 14 figure
Pathway to the Square Kilometre Array - The German White Paper -
The Square Kilometre Array (SKA) is the most ambitious radio telescope ever
planned. With a collecting area of about a square kilometre, the SKA will be
far superior in sensitivity and observing speed to all current radio
facilities. The scientific capability promised by the SKA and its technological
challenges provide an ideal base for interdisciplinary research, technology
transfer, and collaboration between universities, research centres and
industry. The SKA in the radio regime and the European Extreme Large Telescope
(E-ELT) in the optical band are on the roadmap of the European Strategy Forum
for Research Infrastructures (ESFRI) and have been recognised as the essential
facilities for European research in astronomy.
This "White Paper" outlines the German science and R&D interests in the SKA
project and will provide the basis for future funding applications to secure
German involvement in the Square Kilometre Array.Comment: Editors: H. R. Kl\"ockner, M. Kramer, H. Falcke, D.J. Schwarz, A.
Eckart, G. Kauffmann, A. Zensus; 150 pages (low resolution- and colour-scale
images), published in July 2012, language English (including a foreword and
an executive summary in German), the original file is available via the MPIfR
homepag
Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background
The intergalactic magnetic field (IGMF) may leave an imprint on the angular
anisotropy of the extragalactic gamma-ray background through its effect on
electromagnetic cascades triggered by interactions between very high energy
photons and the extragalactic background light. A strong IGMF will deflect
secondary particles produced in these cascades and will thus tend to isotropize
lower energy cascade photons, thereby inducing a modulation in the anisotropy
energy spectrum of the gamma-ray background. Here we present a simple,
proof-of-concept calculation of the magnitude of this effect and demonstrate
that current Fermi data already seem to prefer non-negligible IGMF values. The
anisotropy energy spectrum of the Fermi gamma-ray background could thus be used
as a probe of the IGMF strength.Comment: 11 pages, 4 figures, MN LaTeX style; accepted for publication in
MNRA
The future of gamma-ray astronomy
The field of gamma-ray astronomy has experienced impressive progress over the
last decade. Thanks to the advent of a new generation of imaging air Cherenkov
telescopes (H.E.S.S., MAGIC, VERITAS) and thanks to the launch of the Fermi-LAT
satellite, several thousand gamma-ray sources are known today, revealing an
unexpected ubiquity of particle acceleration processes in the Universe. Major
scientific challenges are still ahead, such as the identification of the nature
of Dark Matter, the discovery and understanding of the sources of cosmic rays,
or the comprehension of the particle acceleration processes that are at work in
the various objects. This paper presents some of the instruments and mission
concepts that will address these challenges over the next decades.Comment: To be published in Comptes Rendus Physique (2016
Working Papers: Astronomy and Astrophysics Panel Reports
The papers of the panels appointed by the Astronomy and Astrophysics survey Committee are compiled. These papers were advisory to the survey committee and represent the opinions of the members of each panel in the context of their individual charges. The following subject areas are covered: radio astronomy, infrared astronomy, optical/IR from ground, UV-optical from space, interferometry, high energy from space, particle astrophysics, theory and laboratory astrophysics, solar astronomy, planetary astronomy, computing and data processing, policy opportunities, benefits to the nation from astronomy and astrophysics, status of the profession, and science opportunities
The History of Astrophysics in Antarctica
We examine the historical development of astrophysical science in Antarctica
from the early 20th century until today. We find three temporally overlapping
eras, each having a rather distinct beginning. These are the astrogeological
era of meteorite discovery, the high energy era of particle detectors, and the
photon astronomy era of microwave, sub--mm and infrared telescopes, sidelined
by a few niche experiments at optical wavelengths. The favourable atmospheric
and geophysical conditions are briefly examined, followed by an account of the
major experiments and a summary of their results.Comment: 29 pages, 10 figures, 1 table Submitted to PASA in April 200
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