28-29 October 2011
University of Wisconsin Pyle Center
US/Central timezone
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Displaying 28 contributions out of 28
This talk summarizes the recent observations of the interaction of the heliosphere with the local interstellar medium as observed remotely by the Interstellar Boundary Explorer (IBEX). IBEX observations have shown that the interaction is far more complex and dynamic than previously anticipated and raised many new questions about this important interaction.
Presented by Dr. David MCCOMAS on 29 Oct 2011 at 14:30
The EAS-TOP Extensive Air Shower array was located at Campo Imperatore (2005 m a.s.l., latitude 42◦27N, longitude 13◦34E, INFN Gran Sasso National Laboratory). It took cosmic ray data in the energy range 10^13 eV-10^16 eV from the end of 1980s up to 2000. A first data-set (including 4 years of data) was exploited for the measurement of the cosmic ray anisotropy at E≈10^14 eV (Ap. J. 470, 199 ... More
Presented by Dr. Piera Luisa GHIA on 28 Oct 2011 at 15:00
EAS array dataset contains signal laying on different angular scales: point-like and extended gamma-ray sources, as well as large and intermediate scale cosmic-ray anisotropies. The separation of all these contributions is crucial, mostly when they overlap with each other. In recent years, the needlet transform has proved to be an effective tool in the analysis of cosmological and astrophysic ... More
Presented by Roberto IUPPA on 28 Oct 2011 at 15:30
Magnetic reconnection in realistically turbulent astrophysical environments does not depend on electric conductivity of plasma, but instead is controlled by the degree of turbulent stochasticity of magnetic field lines. Such a reconnection can induce the first order Fermi acceleration of energetic particles. I will show that this acceleration is different in 2D and 3D reconnection with 3D reconnec ... More
Presented by Prof. Alex LAZARIAN on 28 Oct 2011 at 11:20
We propose an explanation for the origin of the observed cosmic ray anisotropies at multiple scales. We discuss its implications, and future perspectives.
Presented by Dr. Gwenael GIACINTI on 28 Oct 2011 at 17:10
Both the acceleration of cosmic rays (CR) in supernova remnant shocks and their subsequent propagation through the random magnetic field of the Galaxy deem to result in an almost isotropic CR spectrum. Yet the MILAGRO TeV observatory and the IceCube discovered sharp (~10 deg) arrival anisotropies of CR nuclei. We suggest a mechanism for producing such a CR beam which operates en route to the ... More
Presented by Dr. Mikhail MALKOV on 28 Oct 2011 at 11:50
To measure the per-mille anisotropy in the TeV cosmic rays with a ground-based experiment, it is necessary to estimate the exposure of the detector to cosmic ray air showers. The estimate must account for drifts that occur in the detector during the course of the measurement, as well as changes in the shower signal at ground level caused by atmospheric conditions. Due to the difficulty of t ... More
Presented by Dr. Segev BENZVI on 28 Oct 2011 at 16:00
I will discuss the role of anisotropy as a tool to discriminate among different scenarios for the origin of Galactic cosmic rays. The main aim of the presentation is that of stressing the need for a unified picture of acceleration, propagation, chemical composition and anisotropy. I will summarize the different contributions to cosmic ray anisotropies and the problems with current observations, es ... More
Presented by Prof. Pasquale BLASI on 29 Oct 2011 at 12:30
The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory (Tibet, 4300 m asl, 606 g/cm2), is an EAS-array exploiting the full coverage approach at high altitude. We analyzed the data taken since November 2007 looking for anisotropies in the arrival directions of cosmic rays on different angular scales. The results of the analysis are reported and compared with other experiments ... More
Presented by Roberto IUPPA on 28 Oct 2011 at 10:00
The AMANDA detector has been operated at the South Pole until 2006 and recorded a total ~9·10^9 muons above ~1 TeV between 2000 and 2006. With a data set of this size, it is possible to probe the southern sky for per-mil anisotropy on all angular scales in the arrival direction distribution of cosmic rays thereby extending anisotropy measurements performed with IceCube. The data presented here ... More
Presented by Maria GURTNER on 28 Oct 2011 at 14:30
After five years of data taking in space, the PAMELA experiment has presented new results on the energy spectra of protons, helium nuclei, electrons and positrons that might change our current understanding of the mechanisms of production, acceleration and propagation of cosmic rays in the Galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constrai ... More
Presented by Dr. Mirko BOEZIO on 29 Oct 2011 at 11:30
Similar directions are obtained for the local interstellar magnetic field (ISMF) by comparing diverse data that sample five orders of magnetic in spatial scales. The direction of the ISMF that shapes the heliosphere, and that is traced by the ribbon of energetic neutral atoms discovered by the Interstellar Boundary Explorer (IBEX) mission, is compared to the ISMF direction obtained from line ... More
Presented by Dr. Priscilla FRISCH on 29 Oct 2011 at 16:30
All current global models of the heliosphere are based on the assumption that the magnetic field in the heliosheath connects back to the Sun. In particular, models of transports of galactic cosmic rays (GCR) assume the heliospheric current sheet is laminar as well. The sectored magnetic field due to the flapping of the heliospheric current sheet compresses across the termination shock and may rec ... More
Presented by Prof. Merav OPHER on 29 Oct 2011 at 15:00
Additional information: http://iopscience.iop.org/2041-8205/714/1/L89/
Presented by Prof. Eun-Suk SEO on 29 Oct 2011 at 11:00
Research in many areas of modern physics such as, e.g., indirect searches for dark matter and particle acceleration in supernova remnant shocks rely heavily on studies of cosmic rays (CRs) and associated diffuse emissions (radio, microwave, X-rays, gamma rays). The numerical Galactic CR propagation code GALPROP has been shown to reproduce simultaneously observational data of many kinds related to ... More
Presented by Dr. Igor MOSKALENKO on 29 Oct 2011 at 09:30
The solar wind interacts with the local interstellar medium via both ionized and neutral gases. The primary coupling mechanism, charge exchange between protons and interstellar hydrogen, plays a critical role in determining the local structure, as does the interstellar magnetic field. We will describe the basic physical processes underlying the interaction between the solar wind and local in ... More
Presented by Prof. Gary ZANK on 29 Oct 2011 at 10:00
Presented by Dr. Paolo DESIATI on 28 Oct 2011 at 08:45
Scrutiny of the large scale distribution of arrival directions of cosmic rays with energies above ~100 PeV is one important observable to provide key elements for understanding the end of Galactic cosmic rays, and for establishing at which energy the flux of extragalactic cosmic rays starts to dominate the cosmic ray energy spectrum. Using the large amount of data collected by the Pierre Auge ... More
Presented by Dr. Olivier DELIGNY on 28 Oct 2011 at 16:40
The Large Area Telescope on board the Fermi satellite detected more than 1.6 million cosmic-ray electrons/positrons with energies above 60 GeV during its first year of operation. The arrival directions of these events were searched for anisotropies of angular scales from ~10deg up to 90deg, and of minimum energy extending from 60GeV up to 480GeV. Two independent techniques were used to search for ... More
Presented by Dr. Vlasios VASILEIOU on 29 Oct 2011 at 09:00
The Sun moves through the local interstellar medium (LISM) ejecting charged particles with velocities that eventually become greater than the fast magnetosonic velocity. A surface separating the LISM material from the solar wind (SW) plasma is called the heliopause. The SW is decelerated by the heliopause creating a heliospheric termination shock. A region of the SW plasma between the terminati ... More
Presented by Prof. Nikolai POGORELOV on 29 Oct 2011 at 16:00
The talk will focus focuses on the measurement and analysis of the cosmic ray anisotropy obtained by Tibet air shower array.
Presented by Dr. Zhang YI
The IceCube Neutrino Observatory, located at the geographic South Pole, employs a km<sup>3</sup> of Antarctic ice as a particle detector to search for sources of astrophysical neutrinos across the southern sky. The high rate of CR events in the detector has allowed to search for anisotropy in this data sample at the per-mille level. I'll report on the observation of CR anisotropy in the 20 TeV to ... More
Presented by Marcos SANTANDER on 28 Oct 2011 at 10:30
The history of anisotropy measurements has a long history and some attempts at interpretations have already been made. The early measurements are important in view of giving a check on the validity of the contemporary exciting measurements. So far they seem to confirm and complement them, at least for the large scale anisotropies. The small scale anisotropies, forming 'striations' perpendic ... More
Presented by Dr. Rasha ABBASI on 29 Oct 2011 at 17:00
One of the key observables to understand the origin and the sources of Galactic cosmic rays is their elemental composition. The abundance of elements is measured directly with detectors above the atmosphere on balloons and satellites. At energies exceeding 10^14 eV information on the composition is derived from the observation of extensive air showers. Results of recent measurements will be review ... More
Presented by Prof. Jörg HöRANDEL on 29 Oct 2011 at 12:00
The ARGO-YBJ experiment is located at Yang Ba Jing (P.R. China), at 4300 m a.s.l. and atmospheric depth of 606 g/cm^2. It is an air shower detector array with a fully covered layer of Resistive Plate Chambers. It is designed to detect EAS in the primary energy range between few hundred GeV and a few PeV. It has been continuously operated with a duty cycle above 86% since November 2007 observing ab ... More
Presented by Dr. Songzhan CHEN on 28 Oct 2011 at 09:30
The spectra of cosmic electrons and positrons should have contributions from known sources such as particles accelerated in supernova remnants and from interactions of cosmic and interstellar protons. Any evidence for an additional component, as reported by PAMELA, Fermi and HESS experiments, may carry hints of a new phenomenon. I will examine the implications of the recent detection of extended ... More
Presented by Dr. Hasan YUKSEL on 28 Oct 2011 at 17:40
The presence of a large-scale anisotropy in the cosmic radiation has been known for several decades. Earlier experiments lacked the statistical power to observe small-scale anisotropies in the cosmic radiation and there were good reasons to expect that on small scales the cosmic radiation would be smooth. The Milagro extensive air shower array discovered the presence of at least two small (of or ... More
Presented by Dr. John PRETZ on 28 Oct 2011 at 09:00
The observed interstellar anisotropies of galactic cosmic rays, and their energy dependence, are a major source of information concerning their origin and transport in the galaxy. They also present significant challenges to our understanding. I will discuss possible interpretations of some of the anisotropies in terms of interstellar transport in the interstellar magnetic field and some ... More
Presented by Prof. J.R. (Randy) JOKIPII on 28 Oct 2011 at 12:20