摘要:

The title I was asked to speak about expresses an idea that occurred rather recently in the history of cosmic ray studies. I argue that the idea of a possible end of the cosmic ray energy spectrum came into being after a sequence of three rapid advances in knowledge which I describe, calling them ‘breakthroughs.’ I suggest that the present workshop be regarded as a step toward a fourth breakthrough. I argue that this may occur through application of the Space Airwatch concept—the earth atmosphere as target and signal generator—as embodied in the NASA OWL project. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56110

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We summarize the status of the search for the origin of the highest energy cosmic rays. We briefly mention several competing proposals, such as Gamma Ray Bursts also giving rise to energetic protons, high energy neutrinos and cosmological defects, and then concentrate on the possibility that powerful radio galaxies can provide the sources. We describe several tests, some of which have been performed already. First, powerful radio galaxies must be able to accelerate protons to such energies; this entails that there is sufficient space for the Larmor motion. Second, we require at least one candidate radio galaxy with sufficiently strong shock fronts to be the source, at a sufficiently close cosmological distance. Third, the distribution of arrival directions of the highest energy particles on the sky ought to reflect the source distribution as well as the propagation history. The present status can be summarized as inconclusive. Powerful radio galaxies have been tested more than any other candidate source class, but a definitive confirmation is still outstanding. If we were able to confirm this particular theory—or any other—these particles at beyond1020 eVmay be turned into tools of high energy physics. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56114

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

It has been suggested that colliding galaxy pairs could produce cosmic rays with energies⩾1019electron volts. We investigate such a system to see if such energies are likely. We find that there is a typical scale energy associated with a large moving magnetic field structure that is the same whether it is in the form of a diffusive plasma shock or a more regular field structure with little or no irregularity. This scaling leads to the conclusion that such energies as suggested are unlikely to be produced by colliding galaxies. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56125

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Extreme Energy Cosmic Ray particles (EECR) withE>1020 eVarriving on Earth with very low flux (∼1 particle/Km2-1000yr) require for their investigation very large detecting areas, exceeding values of 1000 km2 sr. Projects with these dimensions are now being proposed: Ground Arrays (“Auger” with2×3500 km2 sr) or exploiting the Earth Atmosphere as seen from space (“AIR WATCH” and OWL,” with effective area reaching 1 million km2 sr). In this last case, by using as a target the1013tons of air viewed, also the high energy neutrino flux can be investigated conveniently. Gamma Rays Bursts are suggested as a possible source for EECR and the associated High Energy neutrino flux. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56132

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

In the early days before the Fly’s Eye project start in 1974, K. Greisen began the pioneering work to detect air fluorescence light from the very high energy cosmic ray showers. 5 years late after this, G. Tanahashi started the same work in Tokyo. Both works had2∼3versions. These works are summarized. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56139

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We summarize the history of the Flys Eye detector project and discuss results on the UHE cosmic ray spectrum and composition produced by this experiment. The design and present status of the High Resolution Fly’s Eye is discussed. Results on the UHE composition from the HiRes prototype/CASA/MIA detector are presented. Plans for a new collaboration with the Telescope Array group to build the Snake detector are discussed. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56147

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Recent results on primary cosmic rays of energies above1×1019 eVobserved by the Akeno Giant Air Shower Array (AGASA) are summarized. It is likely that extremely high energy cosmic rays are from diffuse sources distributed isotropically in the universe. However, there are cosmic rays of energies in excess of the predicted cutoff energy and some fraction of cosmic rays beyond4×1019 eVseem to come nearby sources composing double events within a limited space angle. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56148

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The design strategy of an Airwatch mission intended to study cosmic rays at energies above1019 eVis presented. Cosmic Rays having so Extreme Energies (EECR) can be studied through the fluorescence light their showers excite in the Earth’s atmosphere, as seen by a detector mounted on a space platform. According to the Airwatch concept a single detector can be used for measuring both intensity and time development of the streak of fluorescence light produced by the atmospheric shower of an EECR. Both an explorative mission on a small free flyer and a high statistics mission are considered. In order to optimize the design of this space mission, preliminary measurements are forseen with the UVSTAR apparatus flying on the Shuttle and looking at the fluorescence light excited in the atmosphere by a laser. These measurements will provide data for signal to background evaluation. A laboratory measurement of the fraction of ionization energy going in fluorescence light in the air, as a function of pressure, temperature and chemical composition, is also planned. A high intensity X-ray beam will be used for the purpose. This measurement is important in order to evaluate the possibility of detecting GRB impacting on the entire atmosphere. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56140

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

High statistics observation of the highest energy cosmic rays is needed to extend the present data and resolve the astrophysical question of the origin of these particles. Use of the nitrogen fluorescence technique to make observations from space of the giant air showers induced by these cosmic rays is a promising approach. We consider the technical requirements upon an instrument capable of such measurements. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56149

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

In this paper scientific goals of the project to operate a large mirror camera in the Russian segment of ISS are discussed. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56104

出版商:AIP    

年代:1998

数据来源: AIP