These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

How to Detect Cosmic Rays  

NSDL National Science Digital Library

In this lesson on cosmic rays, students will explain two examples of a cosmic ray detector. Includes information about student preconceptions and a demonstration that requires a geiger counter and optional access to a small radioactive source that emits energetic helium nuclei (alpha particles), e.g., the mineral the mineral autunite, which contains uranium. This is activity two of four from The Cosmic Ray Telescope for the Effects of Radiation (CRaTER).

2

Radar Detection of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Progress in the study of high energy cosmic ray physics is limited by low flux. In order to collect substantial statistics above 10^19 eV, the two largest ground arrays currently in operation cover 800 km^2 (Telescope Array, Utah) and 3000 km^2 (Auger Observatory, Argentina). The logistics and cost of an order-of-magnitude increase in ground array aperture is prohibitive. In the literature, radar detection experiments have been proposed but substantial results have not been reported. We have deployed a low-power (1500 W) bistatic radar facility overlapping the Telescope Array (TA) in Delta, Utah. Data acquisition systems for the radar receivers were developed in parallel. This system has taught us a great deal, but our current focus is building and deploying a 40 kW transmitter and new high-gain transmitting antenna. Theoretical simulations of CR air shower scattering of radar show that coincidences with the ground array should be detected with this new system. An FCC license for the new transmitter/antenna has been obtained. Systems monitoring and data logging systems, as well as a new, intelligent self-triggered DAQ continue to be developed. We hope to deploy the self-triggered DAQ during the first few months of 2012 and complete the transmitte

Myers, Isaac

2012-03-01

3

30TH INTERNATIONAL COSMIC RAY CONFERENCE Radio Detection of UltraHigh Energy Cosmic Rays  

E-print Network

30TH INTERNATIONAL COSMIC RAY CONFERENCE Radio Detection of Ultra­High Energy Cosmic Rays HEINO from cosmic rays, confirmed the geosynchrotron effect for extensive air showers, and provided a good rays and the usage of the LOFAR radio telescope (and later the SKA) as a cosmic ray detector. Here

Falcke, Heino

4

Research Concerning Detection of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Throughout my academic career at Loyola I have carried out research with the Loyola University Cosmic Event Detection System concerning the possibility of detection of ultra high energy cosmic rays (UHECRs) based on radio meteor scattering methods. This research was furthered through summer internships and research fellowships at Adler Planetarium Chicago and Stony Brook University in New York. At Adler Planetarium we used a helium balloon carrying a Geiger counter and other equipment to record the cosmic ray flux at various points in the atmosphere. The results clearly show the flux depends on the atmospheric density. At Stony Brook University I studied their advanced system for detecting cosmic rays in similar manner to radio meteor scattering principles. Research there focused on detection algorithms and also on the possibility of utilizing Digital Tv (DTv) signals for further research. Through the research a solid understanding of cosmic rays was formed including topics such as origins and energy scales of cosmic rays, both of which pose unanswered questions. )

Grady, Maxwell; Cunningham, John; Kuhlmann, Steve; Spinka, Hal; Underwood, Dave; Hammergren, Mark

2010-02-01

5

Radio detection of cosmic ray air showers with LOPES  

E-print Network

In the last few years, radio detection of cosmic ray air showers has experienced a true renaissance, becoming manifest in a number of new experiments and simulation efforts. In particular, the LOPES project has successfully implemented modern interferometric methods to measure the radio emission from extensive air showers. LOPES has confirmed that the emission is coherent and of geomagnetic origin, as expected by the geosynchrotron mechanism, and has demonstrated that a large scale application of the radio technique has great potential to complement current measurements of ultra-high energy cosmic rays. We describe the current status, most recent results and open questions regarding radio detection of cosmic rays and give an overview of ongoing research and development for an application of the radio technique in the framework of the Pierre Auger Observatory.

Tim Huege; the LOPES Collaboration

2006-09-15

6

Are vertical cosmic rays the most suitable to radio detection ?  

E-print Network

The electric field induced by extensive air showers generated by high energy cosmic rays is considered and, more specifically, its dependence on the shower incident angle. It is shown that for distances between the shower axis and the observation point larger than a few hundred meters, non-vertical showers produce larger fields than vertical ones. This may open up new prospects since, to some extent, the consideration of non-vertical showers modifies the scope of the radio-detection domain.

T. Gousset; O. Ravel; C. Roy

2004-02-18

7

Fibre laser hydrophones for cosmic ray particle detection  

NASA Astrophysics Data System (ADS)

The detection of ultra high energetic cosmic neutrinos provides a unique means to search for extragalactic sources that accelerate particles to extreme energies. It allows to study the neutrino component of the GZK cut-off in the cosmic ray energy spectrum and the search for neutrinos beyond this limit. Due to low expected flux and small interaction cross-section of neutrinos with matter large experimental set-ups are needed to conduct this type of research. Acoustic detection of cosmic rays may provide a means for the detection of ultra-high energetic neutrinos. Using relative low absorption of sound in water, large experimental set-ups in the deep sea are possible that are able to detect these most rare events, but it requires highly sensitive hydrophones as the thermo-acoustic pulse originating from a particle shower in water has a typical amplitude as low as a mPa. It has been shown in characterisation measurements that the fibre optic hydrophone technology as designed and realised at TNO provides the required sensitivity. Noise measurements and pulse reconstruction have been conducted that show that the hydrophone is suited as a particle detector.

Buis, E. J.; Doppenberg, E. J. J.; Nieuwland, R. A.; Toet, P. M.

2014-03-01

8

Student Projects in Cosmic Ray Detection  

ERIC Educational Resources Information Center

The Alberta Large-area Time-coincidence Array (ALTA) study has been in existence for about 10 years under the direction of Jim Pinfold of the Centre for Particle Physics at the University of Alberta. The purpose of the ALTA project is to involve Alberta high schools, and primarily their physics classes, to assist in the detection of the presence…

Brouwer, W.; Pinfold, J.; Soluk, R.; McDonough, B.; Pasek, V.; Bao-shan, Zheng

2009-01-01

9

Cosmic Ray Inspection and Passive Tomography for SNM Detection  

SciTech Connect

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon tracking system for the full scale prototype will be based on drift chambers or extruded scintillator trackers. An analysis of the operations of the Port of Montreal has determined how long muon scan times should take if all or a subset of the cargo is to be screened. As long as the throughput of the muon system(s) is equal to the rate at which containers are unloaded from ships, the impact on port operations would not be great if a muon scanning stage were required for all cargo. We also show preliminary simulation results indicating that excellent separation between Al, Fe and Pb is possible under ideal conditions. The discrimination power is reduced but still significant when realistic momentum resolution measurements are considered.

Armitage, John; Oakham, Gerald [Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6 (Canada); Bryman, Douglas [Advanced Applied Physics Solutions, 4004 Westbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Cousins, Thomas; Noeel, Scott [International Safety Research, 38 Colonnade Rd. N. Ottawa, ON, K2E 7J6 (Canada); Gallant, Grant [Canadian Border Services Agency, Laboratory and Scientific Services Directorate, 79 Bentley Avenue, Ottawa, ON, K2E 6T7 (Canada); Jason, Andrew [Los Alamos National Laboratories, MS H817, Los Alamos National Laboratory, Los Alamos, NM, USA 87544 (United States); Jonkmans, Guy [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada); Stocki, Trevor J. [Radiation Protection Bureau, Health Canada, 775 BrookfieldRd, A.L. 6302D1, Ottawa, ON, K1A 1C1 (Canada); Waller, David [Defence Research and Development Canada-Ottawa, 3701 Carling Avenue, Ottawa, ON, K1A 0Z4 (Canada)

2009-12-02

10

ESA's Integral detects closest cosmic gamma-ray burst  

NASA Astrophysics Data System (ADS)

5 August 2004 A gamma-ray burst detected by ESA's Integral gamma-ray observatory on 3 December 2003 has been thoroughly studied for months by an armada of space and ground-based observatories. Astronomers have now concluded that this event, called GRB 031203, is the closest cosmic gamma-ray burst on record, but also the faintest. This also suggests that an entire population of sub-energetic gamma-ray bursts has so far gone unnoticed... Gamma ray burst model hi-res Size hi-res: 22 KB Credits: CXC/M. Weiss Artist impression of a low-energy gamma-ray burst This illustration describes a model for a gamma-ray burst, like the one detected by Integral on 3 December 2003 (GRB 031203). A jet of high-energy particles from a rapidly rotating black hole interacts with surrounding matter. Observations with Integral on 3 December 2003 and data on its afterglow, collected afterwards with XMM-Newton, Chandra and the Very Large Array telescope, show that GRB 031203 radiated only a fraction of the energy of normal gamma-ray bursts. Like supernovae, gamma-ray bursts are thought to be produced by the collapse of the core of a massive star. However, while the process leading to supernovae is relatively well understood, astronomers still do not know what happens when a core collapses to form a black hole. The discovery of 'under-energetic' gamma-ray bursts, like GRB 031203, should provide valuable clues as to links between supernovae, black holes and gamma-ray bursts. Lo-res JPG (22 Kb) Hi-res TIFF (5800 Kb) Cosmic gamma-ray bursts (GRBs) are flashes of gamma rays that can last from less than a second to a few minutes and occur at random positions in the sky. A large fraction of them is thought to result when a black hole is created from a dying star in a distant galaxy. Astronomers believe that a hot disc surrounding the black hole, made of gas and matter falling onto it, somehow emits an energetic beam parallel to the axis of rotation. According to the simplest picture, all GRBs should emit similar amounts of gamma-ray energy. The fraction of it detected at Earth should then depend on the 'width' (opening angle) and orientation of the beam as well as on the distance. The energy received should be larger when the beam is narrow or points towards us and smaller when the beam is broad or points away from us. New data collected with ESA's high energy observatories, Integral and XMM-Newton, now show that this picture is not so clear-cut and that the amount of energy emitted by GRBs can vary significantly. "The idea that all GRBs spit out the same amount of gamma rays, or that they are 'standard candles' as we call them, is simply ruled out by the new data," said Dr Sergey Sazonov, from the Space Research Institute of the Russian Academy of Sciences, Moscow (Russia) and the Max-Planck Institute for Astrophysics, Garching near Munich (Germany). Sazonov and an international team of researchers studied the GRB detected by Integral on 3 December 2003 and given the code-name of GRB 031203. Within a record 18 seconds of the burst, the Integral Burst Alert System had pinpointed the approximate position of GRB 031203 in the sky and sent the information to a network of observatories around the world. A few hours later one of them, ESA's XMM-Newton, determined a much more precise position for GRB 031203 and detected a rapidly fading X-ray source, which was subsequently seen by radio and optical telescopes on the ground. This wealth of data allowed astronomers to determine that GRB 031203 went off in a galaxy less than 1300 million light years away, making it the closest GRB ever observed. Even so, the way in which GRB 031203 dimmed with time and the distribution of its energy were not different from those of distant GRBs. Then, scientists started to realise that the concept of the 'standard candle' may not hold. "Being so close should make GRB 031203 appear very bright, but the amount of gamma-rays measured by Integral is about one thousand times less than what we would normally expect from a GRB," Sazonov said. A burst of gamma rays ob

2004-08-01

11

Hoping to indirectly detect Dark Matter with cosmic rays  

NASA Astrophysics Data System (ADS)

Dark Matter constitutes more that 80% of the total amount of matter in the Universe, yet almost nothing is known about its nature. A powerful investigation technique is that of searching for the products of annihilations of Dark Matter particles in the galactic halo, on top of the ordinary cosmic rays. Recent data from the PAMELA and FERMI satellites and a number of balloon experiment have reported unexpected excesses in the measured fluxes of cosmic rays. Are these the first direct evidences for Dark Matter? If yes, which DM models and candidates can explain these anomalies (in terms of annihilations) and what do they imply for future searches? What are the constraints from gamma rays measurements and cosmology? [Report number: Saclay T-10/098, CERN-PH-TH/2010-183].

Cirelli, Marco

2010-11-01

12

LPDA-Antennas for Large Scale Radio Detection of Cosmic Rays at the  

E-print Network

LPDA-Antennas for Large Scale Radio Detection of Cosmic Rays at the Pierre-Auger-Observatory von Profiles and Methods of Observation . . . . . . . . . . . . . . 13 3.2.1 Longitudinal Shower Profile Parameters . . . . . . . . . . . . . . . . . . . . . . 39 5.2.3 Impedance Matching

Erdmann, Martin

13

26. Cosmic rays 1 26. COSMIC RAYS  

E-print Network

26. Cosmic rays 1 26. COSMIC RAYS Revised August 2011 by J.J. Beatty (Ohio State Univ.) and J or longer. Technically, "primary" cosmic rays are those particles accelerated at astrophysical sources decelerates and partially excludes the lower energy galactic cosmic rays from the inner solar system

14

24. Cosmic rays 1 24. COSMIC RAYS  

E-print Network

24. Cosmic rays 1 24. COSMIC RAYS Revised August 2011 by J.J. Beatty (Ohio State Univ.) and J or longer. Technically, "primary" cosmic rays are those particles accelerated at astrophysical sources decelerates and partially excludes the lower energy galactic cosmic rays from the inner solar system

15

24. Cosmic rays 1 24. COSMIC RAYS  

E-print Network

24. Cosmic rays 1 24. COSMIC RAYS Revised August 2009 by T.K. Gaisser and T. Stanev (Bartol or longer. Technically, "primary" cosmic rays are those particles accelerated at astrophysical sources decelerates and partially excludes the lower energy galactic cosmic rays from the inner solar system

16

COSMIC-RAY MUON TOMOGRAPHY AND ITS APPLICATION TO THE DETECTION OF HIGH-Z MATERIALS  

E-print Network

, like uranium and plutonium, and gamma-ray shielding materials, like lead, tungsten or gold SNM and most effective gamma-ray shielding materials have high densities and atomic numbers (Z). A new. This allowed us to develop a technique which uses multiple scattering of cosmic-ray muons to detect shielded

Kurien, Susan

17

Detection of ultrahigh-energy cosmic rays and neutrinos by radio method using artificial lunar satellites  

Microsoft Academic Search

An estimate of the feasibility of the ultrahigh-energy cosmic ray and neutrino detection using a lunar satellite-borne radio\\u000a receiver is presented. The data obtained in the proposed experiment will make resolving the current contradictions in the\\u000a ultrahigh-energy cosmic ray spectra measured with the major ground-based instruments possible. Moreover, they will enable\\u000a us to considerably extend the accessible energy range and

G. A. Gusev; B. N. Lomonosov; K. M. Pichkhadze; N. G. Polukhina; V. A. Ryabov; T. Saito; V. K. Sysoev; E. L. Feinberg; V. A. Tsarev; V. A. Chechin

2006-01-01

18

First Informal MiniWorkshop on Acoustic Cosmic Ray and Neutrino Detection  

E-print Network

particle detection in water: activities in Erlangen 3:20-3:40 Break 3:40-4:20 Rolf Nahnhauer (ZeuthenFirst Informal MiniWorkshop on Acoustic Cosmic Ray and Neutrino Detection Physics Department and logistics 9:10-9:50 John Learned (Hawaii) Early work on acoustic detection 9:50-10:30 Buford Price (Berkeley

Learned, John

19

FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Experiments which show coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100 % up time as, e.g., surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g., the Pierre Auger Observatory) as another type of air-shower detector in addition to fluorescence detectors, which operate with only ˜10 % of duty on dark nights. The radio signals from air showers are caused by coherent emission from geomagnetic radiation and charge-excess processes. The self-triggers in radio detectors currently in use often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data require significant manpower for off-line analysis. Improvement of trigger efficiency is a relevant factor. The wavelet trigger, which investigates on-line the power of radio signals (˜V2/R), is promising; however, it requires some improvements with respect to current designs. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not originate from cosmic ray showers but could be the result of human contamination. The engine of the wavelet analysis can be implemented in the modern powerful FPGAs and can remove suspicious events on-line to reduce the trigger rate.

Szadkowski, Zbigniew; Szadkowska, Anna

2014-09-01

20

FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Experiments which show coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100 % up time as, e.g., surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g., the Pierre Auger Observatory) as another type of air-shower detector in addition to fluorescence detectors, which operate with only ˜10 % of duty on dark nights. The radio signals from air showers are caused by coherent emission from geomagnetic radiation and charge-excess processes. The self-triggers in radio detectors currently in use often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data require significant manpower for off-line analysis. Improvement of trigger efficiency is a relevant factor. The wavelet trigger, which investigates on-line the power of radio signals (˜ V2/ R), is promising; however, it requires some improvements with respect to current designs. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not originate from cosmic ray showers but could be the result of human contamination. The engine of the wavelet analysis can be implemented in the modern powerful FPGAs and can remove suspicious events on-line to reduce the trigger rate.

Szadkowski, Zbigniew; Szadkowska, Anna

2014-12-01

21

Measurement of Cosmic-Ray Muon-Capture X-Rays and Application to Nuclear Material Detection  

NASA Astrophysics Data System (ADS)

Muonic X-ray measurement by the use of cosmic muon has a potential to identify nuclear material in containers. We performed a feasibility study by using an iron target. Two plastic scintillators detected incoming cosmic-ray muons and a veto scintillator identified muons stopped in the target. Germanium detectors in coincidence with the scintillators measured muonic X-ray energies. We clearly observed muonic X-ray peaks in the photon spectrum, of which the energies were consistent with known muonic X-ray energies. By using the obtained spectrum, input parameters of the Monte-Carlo simulation were checked. The simulation for uranium target showed that this method is promising.

Shimbara, Y.; Matsuzaki, T.; Abe, K.; Haga, K.; Homma, A.; Kikukawa, N.; Murooka, D.; Nagashima, M.; Nakamura, Y.; Ogura, T.; Sakai, T.; Sera, D.; Tashiro, K.; Goto, J.; Ito, J.; Kato, S.; Ohtsubo, T.; Ohya, S.; Takeda, K.; Tsurumaki, Y.; Yajima, A.; Yoshikawa, T.; Itoh, T.; Tanaka, M.; Suzuki, S.; Yanagi, K.

2015-10-01

22

Detecting Radio Emission from Cosmic Ray Air Showers and Neutrinos with a Digital Radio Telescope  

E-print Network

We discuss the possibilities of measuring ultra-high energy cosmic rays and neutrinos with radio techniques. We review a few of the properties of radio emission from cosmic ray air showers and show how these properties can be explained by coherent ``geosynchrotron'' emission from electron-positron pairs in the shower as they move through the geomagnetic field. This should allow one to use the radio emission as a useful diagnostic tool for cosmic ray research. A new generation of digital telescopes will make it possible to study this radio emission in greater detail. For example, the planned Low-Frequency Array (LOFAR), operating at 10-200 MHz, will be an instrument uniquely suited to study extensive air showers and even detect neutrino-induced showers on the moon. We discuss sensitivities, count rates and possible detection algorithms for LOFAR and a currently funded prototype station LOPES. This should also be applicable to other future digital radio telescopes such as the Square-Kilometer-Array (SKA). LOFAR will be capable of detecting air-shower radio emission from >2*10^14 eV to ~10^20 eV. The technique could be easily extended to include air shower arrays consisting of particle detectors (KASCADE, Auger), thus providing crucial additional information for obtaining energy and chemical composition of cosmic rays. It also has the potential to extend the cosmic ray search well beyond an energy of 10^21 eV if isotropic radio signatures can be found. Other issues that LOFAR can address are to determine the neutral component of the cosmic ray spectrum, possibly look for neutron bursts, and do actual cosmic ray astronomy.

Heino Falcke; Peter Gorham

2002-07-10

23

An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays  

E-print Network

1 An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays Zbigniew of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly powerful FPGA and can remove suspicious events on-line to reduce the trigger rate. Index Terms

24

Cosmic Ray Physics at a Community College: Assembly, Detection and Measurement  

NASA Astrophysics Data System (ADS)

During an in-depth eight week summer research program at Hartnell Community College in Salinas, CA, we constructed two complementary experimental systems to measure cosmic rays. One system used NIM electronic modules configured for coincidence measurement. To detect the comic rays, two photomultiplier tubes each coupled to plastic scintillator paddles were assembled. The other system was build from a circuit board designed by the LBL Cosmic Ray Project. Extensive prototype and diagnosis for this board were done prior to final soldering of the parts. The dependence of the cosmic ray flux on the separation between scintillator paddles was measured and showed reasonable agreement with the accepted value. The flux dependence on the square of the cosine of the polar angle was also tested, and our result showed closely the expected cosine behavior using the NIM setup. As for the LBL Lab circuit board, it was difficult to obtain reliable coincidence counts for large polar angles probably due to the lack of an adjustable discriminator control. This was compensated for by operating the detectors at a lower high voltage which reduced the random counts, without affecting signals. This strategy gave a more reliable cosmic ray flux result using the Berkeley Lab circuit board.

Fan, Sewan; Davis, Scott; Osornio, Leo; Haag, Brooke

2012-03-01

25

Strangelets in Cosmic Rays  

E-print Network

The properties of strangelets are reviewed and two experiments searching for them in cosmic rays are described. The prospects for strangelets as ultra-high energy cosmic rays beyond the classical GZK-cutoff are discussed.

Jes Madsen

2006-12-29

26

X-ray Emissions Detected From Elusive Cosmic Objects  

NASA Astrophysics Data System (ADS)

A type of celestial object that has long stumped astronomers has been found to emit X-rays, thus proving a theory of how the objects form. Dr. Steven Pravdo of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and other scientists have concluded that these objects, called Herbig Haro objects, are produced by high velocity shocks. Pravdo is the lead author of a paper published in the Oct. 18 issue of the journal Nature. Herbig Haro objects are found in regions where new stars are forming. They are nebulas, or dust and gas clouds. They form when high-velocity gas emitted from young stars collides with clouds of interstellar material. The collision heats the gas in the surrounding nebula to sufficiently high temperatures to produce X-rays. Observations for the past 20 years showed no evidence of X-ray emission from these objects, which are named for astronomers George Herbig and Guillermo Haro. Previous instruments lacked the resolution and sensitivity necessary to 'see' these X-rays. The discovery of the X-ray emissions was possible through the very powerful Advanced CCD Imaging Spectrometer on NASA's Chandra X-ray Observatory, which has been in orbit since 1999. On Oct. 8, 2000, astrophysicists used the instrument to study HH2, one of the brightest and closest Herbig Haro objects in the Orion Nebula. They determined that HH2 contains shock-heated material with a temperature of about 1 million degrees Kelvin. Pravdo and his team used three criteria to rule out the possibility that the emissions came from any other source. First, Chandra's high spatial resolution pinpointed the location of the X-rays at HH2. Second, the X-rays appeared to be covering a region bigger than a star. Third, the temperature of the X-rays was about 1 million degrees, cooler than nearby X-ray stars. One million degrees is about the temperature expected if material moving at about 300 kilometers per second (about 600,000 miles per hour) collides. At this speed, you could go from Los Angeles to San Diego and back in one second. The principal investigator of the Advanced CCD Imaging Spectrometer, Dr. Gordon Garmire of Pennsylvania State University, University Park, is a co-author of the paper. Other co-authors include Drs. Yohko Tsuboi, Yoshitomo Maeda and Eric Feigelson, all from Pennsylvania State University, and Dr. John Bally from the University of Colorado, Boulder. The Advanced CCD Imaging Spectrometer X-ray camera was developed for NASA by Pennsylvania State University and the Massachusetts Institute of Technology, Cambridge, Mass. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov The Chandra X-ray Observatory is managed for NASA by the Smithsonian Astrophysical Observatory, Cambridge, Mass. JPL is managed for NASA by the California Institute of Technology in Pasadena.

2001-10-01

27

Solar cosmic ray phenomena  

Microsoft Academic Search

This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories:

K. G. McCracken; U. R. Rao

1970-01-01

28

Detection and imaging of atmospheric radio flashes from cosmic ray air showers.  

PubMed

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing. PMID:15902250

Falcke, H; Apel, W D; Badea, A F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Buitink, S; Brüggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Daumiller, K; de Bruyn, A G; de Vos, C M; Di Pierro, F; Doll, P; Engel, R; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K-H; Kant, G W; Klein, U; Kolotaev, Y; Koopman, Y; Krömer, O; Kuijpers, J; Lafebre, S; Maier, G; Mathes, H J; Mayer, H J; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Pepping, H J; Petcu, M; Petrovic, J; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Schoonderbeek, G; Sima, O; Stümpert, M; Toma, G; Trinchero, G C; Ulrich, H; Valchierotti, S; van Buren, J; van Cappellen, W; Walkowiak, W; Weindl, A; Wijnholds, S; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D

2005-05-19

29

LAT Perspectives in Detection of High Energy Cosmic Ray Electrons  

NASA Technical Reports Server (NTRS)

The GLAST Large Area Telescope (LAT) science objectives and capabilities in the detection of high energy electrons in the energy range from 20 GeV to approx. 1 TeV are presented. LAT simulations are used to establish the event selections. It is found that maintaining the efficiency of electron detection at the level of 30% the residual hadron contamination does not exceed 2-3% of the electron flux. LAT should collect approx. ten million of electrons with the energy above 20 GeV for each year of observation. Precise spectral reconstruction with high statistics presents us with a unique opportunity to investigate several important problems such as studying galactic models of IC radiation, revealing the signatures of nearby sources such as high energy cutoff in the electron spectrum, testing the propagation model, and searching for KKDM particles decay through their contribution to the electron spectrum.

Moiseev, Alexander; Ormes, J. F.; Funk, Stefan

2007-01-01

30

Dual Phase Cosmic Rays  

E-print Network

A calculation based on flat spacetime symmetries shows how there can be two quantum phases. For one, extreme phase change determines a conventional classical trajectory and four-momentum, i.e. mass times four-velocity. The other phase occurs in an effective particle state, with the effective energy and momentum being the rate of change of the phase with respect to time and distance. A cosmic ray proton moves along a classical trajectory, but exists in an effective particle state with an effective energy that depends on the local gravitational potential. Assumptions are made so that a cosmic ray proton in an ultra-high energy state detected near the Earth was in a much less energetic state in interstellar space. A 300 EeV proton incident on the Earth was a 2 PeV proton in interstellar space. The model predicts such protons are in states with even more energy near the Sun than when near the Earth.

Richard Shurtleff

2007-12-30

31

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1991-01-01

32

Detecting radio emission from cosmic ray air showers and neutrinos with a digital radio telescope  

Microsoft Academic Search

We discuss the possibilities of measuring ultra-high energy cosmic rays and neutrinos with radio techniques. We review a few of the properties of radio emission from cosmic ray air showers and show how these properties can be explained by coherent “geosynchrotron” emission from electron–positron pairs in the shower as they move through the geomagnetic field. This should allow one to

Heino Falcke; Peter Gorham

2003-01-01

33

Aerial Neutron Detection of Cosmic-Ray Interactions with the Earth's Surface  

SciTech Connect

We have demonstrated the ability to measure the neutron flux produced by the cosmic-ray interaction with nuclei in the ground surface using aerial neutron detection. High energy cosmic-rays (primarily muons with GeV energies) interact with the nuclei in the ground surface and produce energetic neutrons via spallation. At the air-surface interface, the neutrons produced by spallation will either scatter within the surface material, become thermalized and reabsorbed, or be emitted into the air. The mean free path of energetic neutrons in air can be hundreds of feet as opposed to a few feet in dense materials. As such, the flux of neutrons escaping into the air provides a measure of the surface nuclei composition. It has been demonstrated that this effect can be measured at long range using neutron detectors on low flying helicopters. Radiological survey measurements conducted at Government Wash in Las Vegas, Nevada, have shown that the neutron background from the cosmic-soil interactions is repeatable and directly correlated to the geological data. Government Wash has a very unique geology, spanning a wide variety of nuclide mixtures and formations. The results of the preliminary measurements are presented.

Richard Maurer

2008-09-18

34

Cosmic Ray Astronomy  

E-print Network

Cosmic ray astronomy attempts to identify and study the sources of ultrahigh energy cosmic rays. It is unique in its reliance on charged particles as the information carriers. While no discrete source of ultrahigh energy cosmic rays has been identified so far, a new generation of detectors is acquiring the huge exposure that is needed at the highest energies, where deflection by magnetic fields is minimized and the background from distant sources is eliminated by pion photoproduction. In this paper, we summarize the status of cosmic ray astronomy, describing the detectors and the analysis techniques.

Paul Sommers; Stefan Westerhoff

2008-02-09

35

Cosmic Rays in Thunderstorms  

NASA Astrophysics Data System (ADS)

Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

2013-04-01

36

How Cosmic Rays Affect Humans  

NSDL National Science Digital Library

In this lesson about cosmic rays, students will describe why cosmic rays are dangerous to astronauts. Includes information about student preconceptions. This is activity 3 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

2012-08-03

37

Terrestrial cosmic rays  

Microsoft Academic Search

This paper reviews the basic physics of those cosmic rays which can affect terrestrial electronics. Cosmic rays at sea level consist mostly of neutrons, protons, pions, muons, electrons, and photons. The particles which cause significant soft fails in electronics are those particles with the strong interaction: neutrons, protons, and pions. At sea level, about 95% of these particles are neutrons.

James F. Ziegler

1996-01-01

38

Origin of Cosmic Rays  

Microsoft Academic Search

Contents Introduction S 1. Primary Cosmic Rays Near the Earth a) Chemical composition b) Energy spectrum S 2. Radio-Astronomical Data a) Magnetic bremsstrahlung (synchrotron radiation) b) Certain results of observations and their interpretation (structure of the Galaxy, discrete sources) S 3. Lifetime of Cosmic Rays and Character of Their Motion in the Galaxy and the Metagalaxy a) Nuclear lifetime of

V. L. Ginzburg; S. I. Syrovatsky

1961-01-01

39

Cosmic-ray astrochemistry.  

PubMed

Gas-phase chemistry in the interstellar medium is driven by fast ion-molecule reactions. This, of course, demands a mechanism for ionization, and cosmic rays are the ideal candidate as they can operate throughout the majority of both diffuse and dense interstellar clouds. Aside from driving interstellar chemistry via ionization, cosmic rays also interact with the interstellar medium in ways that heat the ambient gas, produce gamma rays, and produce light element isotopes. In this paper we review the observables generated by cosmic-ray interactions with the interstellar medium, focusing primarily on the relevance to astrochemistry. PMID:23812538

Indriolo, Nick; McCall, Benjamin J

2013-10-01

40

Detection of the Cosmic ?-Ray Horizon From Multiwavelength Observations of Blazars  

DOE PAGESBeta

The first statistically significant detection of the cosmic ?-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the Universe to very high energy (VHE) ?-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from ?-ray observations of cosmological blazars and ?-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy ?-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.

Dominguez, A.; Finke, J. D.; Prada, F.; Primack, J. R.; Kitaura, F. S.; Siana, B.; Paneque, D.

2013-05-24

41

DETECTION OF THE COSMIC {gamma}-RAY HORIZON FROM MULTIWAVELENGTH OBSERVATIONS OF BLAZARS  

SciTech Connect

The first statistically significant detection of the cosmic {gamma}-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the universe to very high energy (VHE) {gamma}-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from {gamma}-ray observations of cosmological blazars and {gamma}-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy {gamma}-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows us a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.

Dominguez, A.; Siana, B. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Finke, J. D. [U.S. Naval Research Laboratory, Space Science Division, Code 7653, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Prada, F. [Campus of International Excellence UAM-CSIC, Cantoblanco, E-28049 Madrid (Spain); Primack, J. R. [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Kitaura, F. S. [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Paneque, D., E-mail: albertod@ucr.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC, Stanford University, Stanford, CA 94305 (United States)

2013-06-10

42

Cosmic rays and grain alignment  

NASA Astrophysics Data System (ADS)

The recent detection of interstellar polarization in the solid CO feature near 4.67mum shows that CO-mantled grains can be aligned in cold molecular clouds. These observations conflict with a theory of grain alignment which attributes the polarization in molecular clouds to the effects of cosmic rays: according to this theory, oblate spheroidal grains with H_2O- and CO_2-dominated ice mantles are spun up to suprathermal energies by molecular evaporation from cosmic ray impact sites, but spin-up does not occur for CO-mantled grains. Motivated by this conflict, we re-examine the effects of cosmic rays on the alignment of icy grains. We show that the systematic torques produced by cosmic rays are insufficient to cause suprathermal spin. In principle, the random torques due to cosmic rays can enhance the efficiency of Davis-Greenstein alignment by raising the grain rotational temperature. However, a significant enhancement would require cosmic ray fluxes 6-7 orders of magnitude larger than the flux in a typical cold cloud.

Lazarian, A.; Roberge, W. G.

1997-06-01

43

Cosmic Rays at the Knee  

E-print Network

Several kinds of measurements are combined in an attempt to obtain a consistent estimate of the spectrum and composition of the primary cosmic radiation through the knee region. Assuming that the knee is a signal of the high-energy end of a galactic cosmic-ray population, I discuss possible signatures of a transition to an extra-galactic population and how they might be detected.

Thomas K. Gaisser

2006-08-25

44

The origin of galactic cosmic rays  

E-print Network

The origin of galactic cosmic rays is one of the most interesting unsolved problems in astroparticle physics. Experimentally, the problem is attacked by a multi-disciplinary effort, namely by direct measurements of cosmic rays above the atmosphere, by air shower observations, and by the detection of TeV $\\gamma$ rays. Recent experimental results are presented and their implications on the contemporary understanding of the origin of galactic cosmic rays are discussed.

Joerg R. Hoerandel

2007-10-29

45

Cosmic rays in astrospheres  

E-print Network

Cosmic rays passing through large astrospheres can be efficiently cooled inside these "cavities" in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front of the astrospherical bow shocks. We study the cosmic ray flux in and around lambda Cephei as an example for an astrosphere. The large-scale plasma flow is modeled hydrodynamically with radiative cooling. We studied the cosmic ray flux in a stellar wind cavity using a transport model based on stochastic differential equations. The required parameters, most importantly, the elements of the diffusion tensor, are based on the heliospheric parameters. The magnetic field required for the diffusion coefficients is calculated kinematically. We discuss the transport in an astrospheric scenario with varying parameters for the transport coefficients. We show that large stellar wind cavities can act as sinks for the galactic cosmic ray flux and thus can give rise to small-scale anisotropies in the direction to...

Scherer, Klaus; Bomans, Dominik; Ferreira, Stefan; Fichtner, Horst; Kleimann, Jens; Strauss, Dutoit; Weis, Kerstin; Wiengarten, Tobias; Wodzinski, Thomas

2015-01-01

46

A cocoon of freshly accelerated cosmic rays detected by Fermi in the Cygnus superbubble.  

PubMed

The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population. PMID:22116880

Ackermann, M; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Belfiore, A; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; de Angelis, A; de Palma, F; Dermer, C D; do Couto E Silva, E; Drell, P S; Dumora, D; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Fukazawa, Y; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hays, E; Jóhannesson, G; Johnson, A S; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knödlseder, J; Kuss, M; Lande, J; Latronico, L; Lee, S-H; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Martin, P; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Parent, D; Pesce-Rollins, M; Pierbattista, M; Piron, F; Pohl, M; Prokhorov, D; Rainò, S; Rando, R; Razzano, M; Reposeur, T; Ritz, S; Parkinson, P M Saz; Sgrò, C; Siskind, E J; Smith, P D; Spinelli, P; Strong, A W; Takahashi, H; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Troja, E; Uchiyama, Y; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Yang, Z; Zimmer, S; Bontemps, S

2011-11-25

47

Cosmic rays in astrospheres  

NASA Astrophysics Data System (ADS)

Context. Cosmic rays passing through large astrospheres can be efficiently cooled inside these "cavities" in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front of the astrospherical bow shocks. Aims: We study the cosmic ray flux in and around ? Cephei as an example for an astrosphere. The large-scale plasma flow is modeled hydrodynamically with radiative cooling. Methods: We study the cosmic ray flux in a stellar wind cavity using a transport model based on stochastic differential equations. The required parameters, most importantly, the elements of the diffusion tensor, are based on the heliospheric parameters. The magnetic field required for the diffusion coefficients is calculated kinematically. We discuss the transport in an astrospheric scenario with varying parameters for the transport coefficients. Results: We show that large stellar wind cavities can act as sinks for the Galactic cosmic ray flux and thus can give rise to small-scale anisotropies in the direction to the observer. Conclusions: Small-scale cosmic ray anisotropies can naturally be explained by the modulation of cosmic ray spectra in huge stellar wind cavities.

Scherer, K.; van der Schyff, A.; Bomans, D. J.; Ferreira, S. E. S.; Fichtner, H.; Kleimann, J.; Strauss, R. D.; Weis, K.; Wiengarten, T.; Wodzinski, T.

2015-04-01

48

Future use of silicon photomultipliers for the fluorescence detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

A sophisticated technique to measure extensive air showers initiated by ultra-high-energy cosmic rays is by means of fluorescence telescopes. Secondary particles of the air shower excite nitrogen molecules of the atmosphere, which emit fluorescence light when they de-excite. Due to their high photon detection efficiency (PDE) silicon photomultipliers (SiPMs) promise to increase the sensitivity of todays fluorescence telescopes which use photomultiplier tubes - for example the fluorescence detector of the Pierre Auger Observatory. On the other hand drawbacks like a small sensitive area, a strong temperature dependency and a high noise rate have to be managed. We present plans for a prototype fluorescence telescope using SiPMs and a special light collecting optical system of Winston cones to increase the sensitive area. In this context we made measurements of the relative PDE of SiPMs depending on the incident angle of light. The results agree with calculations based on the Fresnel equations. Furthermore, measurements of the brightness of the night sky are presented since this photon flux is the main background to the fluorescence signals of the extensive air showers. To compensate the temperature dependency of the SiPM, frontend electronics make use of temperature sensors and microcontrollers to directly adjust the bias-voltage according to the thermal conditions. To reduce the noise rate we study the coincidence of several SiPMs signals triggered by cosmic ray events. By summing up these signals the SiPMs will constitute a single pixel of the fluorescence telescope.

Stephan, Maurice; Hebbeker, Thomas; Lauscher, Markus; Meurer, Christine; Niggemann, Tim; Schumacher, Johannes

2011-10-01

49

Cosmic Ray Dosimetry  

NASA Astrophysics Data System (ADS)

Radiation levels at aircraft cruising altitudes are twenty times higher than at sea level. Thus, on average, a typical airline pilot receives a larger annual radiation dose than some one working in nuclear industry. The main source of this radiation is from galactic cosmic radiation, high energy particles generated by exploding stars within our own galaxy. In this work we study cosmic rays dosimetry at various aviation altitudes using the PARMA model.

Si Belkhir, F.; Attallah, R.

2010-10-01

50

Stable quark matter in cosmic rays?  

E-print Network

Stable lumps of quark matter may be present in cosmic rays at a flux level, which can be detected by high precision cosmic ray experiments sensitive to anomalous "nuclei" with high mass-to-charge ratio. The properties of these lumps, called strangelets, are described, and so is the production and propagation of strangelets in cosmic rays. Two experiments underway which are sensitive to a strangelet flux in the predicted range are briefly described. Finally it is summarized how strangelets circumvent the acceleration problem encountered by conventional candidates for ultra-high energy cosmic rays and move the Greisen-Zatsepin-Kuzmin cutoff to energies well above the observed maximum energies.

Jes Madsen

2005-12-20

51

Cosmic Rays and Climate  

E-print Network

Among the most puzzling questions in climate change is that of solar-climate variability, which has attracted the attention of scientists for more than two centuries. Until recently, even the existence of solar-climate variability has been controversialâ??perhaps because the observations had largely involved correlations between climate and the sunspot cycle that had persisted for only a few decades. Over the last few years, however, diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in cosmogenic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Although this remains a mystery, observations suggest that cloud cover may be influenced by cosmic rays, which are modulated by the solar wind and, on longer time scales, by the geomagnetic fiel...

Kirkby, Jasper

2007-01-01

52

Discovery of cosmic rays  

NASA Astrophysics Data System (ADS)

The mysterious invisible radiation that ionized air was studied a century ago by many scientists. Finally, on 7 August 1912, Victor Hess in his seventh balloon flight that year, reached an altitude of about 5000 m. With his electroscopes on board the hydrogen-filled balloon he observed that the ionization instead of decreasing with altitude increased significantly. Hess had discovered cosmic rays, a discovery that gave him the 1936 Nobel Prize in physics. When research resumed after World War I focus was on understanding the nature of the cosmic radiation. Particles or radiation? Positive or negative? Electrons, positrons or protons? Progress came using new instruments like the Geiger-Muller tube and around 1940 it was clear that cosmic rays were mostly protons.

Carlson, Per

2013-02-01

53

Galactic cosmic rays and nucleosynthesis  

SciTech Connect

The nucleosynthesis of the light elements Li, Be and B by galactic cosmic rays is presented. Observations of cosmic rays and the nuclear reactions responsible for Li, Be and B nucleosynthesis are described, followed by some words on propagation. At the end, some open questions concerning galactic cosmic rays are discussed.

Kiener, Juergen [CSNSM, CNRS-IN2P3 and Universite Paris-Sud, Bat. 104-108, 91405 Orsay Campus (France)

2010-03-01

54

Cosmic ray research Public lecture  

E-print Network

Cosmic ray research Public lecture Serendipity, colorful scientists and the birth of sub energy cosmic rays in Argentina 2 p.m., Wednesday, October 6, 2010 128 Jabara Hall Watkins Visiting powerful, high-energy cosmic rays that periodically bombard Earth. The project includes more than 450

55

Introduction to Cosmic Rays  

E-print Network

Energetic particles, traditionally called Cosmic Rays, were discovered nearly a hundred years ago, and their origin is still uncertain. Their main constituents are the normal nuclei as in the standard cosmic abundances of matter, with some enhancements for the heavier elements; there are also electrons, positrons and anti-protons, but no anti-nuclei. Today we also have information on isotopic abundances, which show some anomalies, as compared with the interstellar medium. The known spectrum extends over energies from a few hundred MeV to 3*10^{20} eV and shows few clear spectral signatures: There is a small spectral break near 5*10^{15} eV, the "knee", where the spectrum turns down; there is another spectral break near 3*10^{18} eV, the "ankle", where the spectrum turns up again. Up to the ankle the cosmic rays are usually interpreted as originating from Galactic supernova explosions; however, we do not know what the origin of the knee is. The particles beyond the ankle have to be extragalactic, it is usually assumed, because the Larmor radii in the Galactic magnetic field are too large; this argument could be overcome if those particles were very heavy nuclei as Fe, an idea which appears to be inconsistent, however, with the airshower data immediately above the energy of the ankle. Due to interaction with the cosmic microwave background there is a strong cut-off expected near 5*10^{19} eV, which is, however, not seen; The high energy cosmic rays beyond this "GZK-cutoff" (after its discoverers Greisen, Zatsepin and Kuzmin) are the challenge to interpret. We will describe the various approaches to understand the origin and physics of cosmic rays (abridged).

Peter Biermann; Guenter Sigl

2002-02-22

56

Non-Invasive Detection of Soil Water Content at Intermediate Field Scale Using Cosmic-Ray Neutrons  

NASA Astrophysics Data System (ADS)

The amount of water in the subsurface is a key factor influencing a range of hydrological and other processes. New measurement methods are investigated to obtain more information on this key issue. One of them is the so called cosmic ray method, recently introduced for soil moisture measurements by Zreda and co-workers. Secondary neutron fluxes, product of the interaction of primary cosmic-rays at the land surface, are strongly moderated by the presence of water in or above soil (soil moisture, snow and biomass water). Neutron counts at the ground/air interface represent a valuable observation at intermediate spatial scale which can be used to quantify stored water while distinguishing different water holding compartments at the land surface. Classical monitoring networks (e.g. MR2 Theta probes, 1-m PR2/6 Profile probes) of soil moisture, other geophysical methods and soil sampling were used to calibrate and to validate the cosmic-ray method. Experimental sites in Germany with different vegetation were selected for testing the cosmic ray method and to obtain time series of water mass integrated over a land surface area of several thousand square meters. Different sets of proportional counters were installed for detection of secondary neutron fluxes and local meteorological data was used to set atmospheric correction factors. Also, vegetation cover and precipitation were determined during the measurement period. Areal mean values of soil moisture based on cosmic-ray neutrons and its observed temporal variability could be compared quantitatively with classical measurement techniques. First observations under different geographical conditions than reported so far are an initial step for further applications using cosmic-ray neutrons in these regions. Other activities such as monitoring of tree water content in forest, real-time soil moisture cross-sections in long distance and snow water equivalent height will have to be investigated to further improve the conversion of neutron counts in a mean soil moisture of a particular area. We believe that this new approach using cosmic-ray neutrons can cover the lack of data for hydrological processes at the intermediate scale between point measurements and large scale measurements, and thus will be important for improving hydrological approaches and catchment scale modeling.

Rivera Villarreyes, C. A.; Baroni, G.; Oswald, S. E.

2010-12-01

57

Direct detection of cosmic rays: through a new era of precision measurements of particle fluxes  

NASA Astrophysics Data System (ADS)

In the last years the direct measurement of cosmic rays received a push forward by the possibility of conducting experiments on board long duration balloon flights, satellites and on the International Space Station. The increase in the collected statistics and the technical improvements in the construction of the detectors permit the fluxes measurement to be performed at higher energies with a reduced discrepancy among different experiments respect to the past. However, high statistical precision is not always associated to the needed precision in the estimation of systematics; features in the particle spectra can be erroneously introduced or hidden. A review and a comparison of the latest experimental results on direct cosmic rays measurements will be presented with particular emphasis on their similarities and discrepancies.

Mocchiutti, E.

2014-11-01

58

Cherenkov detection of cosmic rays in Hanoi: Response to low signals  

NASA Astrophysics Data System (ADS)

A replica of one of the 1660 Cherenkov detectors used in the ground array of the Pierre Auger Cosmic Ray Observatory in Argentina has been constructed on the roof of the VATLY astrophysics laboratory in Ha Noi (Viet Nam). We report on measurements of low amplitude signals using the detector to study event pairs occurring within a small time window. The data include time autocorrelation and charge distributions.

Thao, N. T.; Anh, P. T.; Darriulat, P.; Diep, P. N.; Dong, P. N.; Hiep, N. V.; Hoai, D. T.; Nhung, P. T. T.

2013-05-01

59

Nineteenth International Cosmic Ray Conference. OG Sessions, Volume 3  

NASA Technical Reports Server (NTRS)

Papers submitted for presentation at the 19th International Cosmic Ray Conference are compiled. This volume addresses cosmic ray sources and acceleration, interstellar propagation and nuclear interactions, and detection techniques and instrumentation.

Jones, F. C. (compiler)

1985-01-01

60

Cosmic-ray isotopic composition  

NASA Technical Reports Server (NTRS)

The 'age' of the cosmic rays and the origin of cosmic ray source matter are discussed. General approaches to the interpretation of the abundances of secondary radioactive nuclides are reviewed using Be-10 as an illustration. The present state of Be-10 based cosmic ray age determinations are summarized, briefly mentioning some recent results based on the isotope Al-26. The effects of nonhomogeneous propagation models on the interpretation of the radioactive isotope observations are mentioned. The cosmic ray source isotopic composition is discussed, emphasizing the neon composition. Mass histogram findings on the abundance of various elements in cosmic rays are described and possible reasons for some abundance enhancements are considered.

Wiedenbeck, M. E.

1983-01-01

61

A minimal width of the arrival direction distribution of ultra-high energy cosmic rays detected with the Yakutsk array  

E-print Network

This paper presents the results of searches for anisotropy in arrival directions of ultra-high energy cosmic rays detected with the Yakutsk Array during the 1974--2008 observational period together with available data from other giant extensive air shower arrays working at present. A method of analysis based on a comparison of the minimal width of distributions in equatorial coordinates is applied. As a result, a hypothesis of isotropy in arrival directions is rejected at the $99.5\\%$ significance level. The observed decrease in the minimal width of distribution can be explained by the presence of cosmic ray sources in energy intervals and sky regions according to the recent indications inferred from data of the Yakutsk Array and Telescope Array experiments.

Ivanov, A A

2015-01-01

62

Building a Cloud Chamber (Cosmic Ray Detector)  

NSDL National Science Digital Library

In this activity, students learn about cosmic rays firsthand by building a cloud chamber to detect them. The comprehensive activity includes step-by-step directions for constructing and operating a cloud chamber and ideas for additional experiments.

63

Ultra High Energy Cosmic Rays  

E-print Network

The origin of the particles in the highest energy end of the cosmic ray spectrum is discussed in the context of the wider problem of the origin of the whole cosmic radiation as observed at the Earth. In particular we focus our attention on the acceleration problem and on the transition from galactic to extragalactic cosmic rays.

Pasquale Blasi

2006-09-29

64

Cosmic Rays: "A Thin Rain of Charged Particles."  

ERIC Educational Resources Information Center

Discussed are balloons and electroscopes, understanding cosmic rays, cosmic ray paths, isotopes and cosmic-ray travel, sources of cosmic rays, and accelerating cosmic rays. Some of the history of the discovery and study of cosmic rays is presented. (CW)

Friedlander, Michael

1990-01-01

65

Cosmic reionization by primordial cosmic rays  

NASA Astrophysics Data System (ADS)

Context. After the so-called cosmic recombination, the expanding universe entered into a period of darkness since most of the matter was in a neutral state. About a billion years later, however, the intergalactic space was once again ionized. The process, known as the cosmic reionization, required the operation of mechanisms that are not well understood. Among other ionizing sources, Population III stars, mini-quasars, and X-ray emitting microquasars have been invoked. Aims: We propose that primordial cosmic rays, accelerated at the termination points of the jets of the first microquasars, may have contributed to the reionization of the intergalactic space as well. Methods: We quantify the ionization power of cosmic rays (electrons and protons) in the primordial intergalactic medium. This power is calculated using extensive particle cascade simulations. Results: We establish that, depending on the fraction of electrons to protons accelerated in the microquasar jets, cosmic rays should have contributed to the reionization of the primordial intergalactic medium as much as X-rays from microquasar accretion disks. If the primordial magnetic field was of the order of 10-17 G, as some models suggest, cosmic rays had an important role in ionizing the neutral material far beyond the birth places of the first stars.

Tueros, M.; del Valle, M. V.; Romero, G. E.

2014-10-01

66

On Cosmic Ray Propagation  

NASA Astrophysics Data System (ADS)

Cosmic ray propagation is diffusive because of pitch angle scattering by waves. We demonstrate that if the high-amplitude magnetic turbulence with (delta B)/B ~ 1 is present on top of the mean field gradient, the diffusion becomes asymmetric. As an example, we solve this diffusion problem in one dimension analytically with a Markov chain analysis. The cosmic ray density markedly differs from the standard diffusion prediction. The equation for the continuous limit is also derived, which shows limitations of the convection-diffusion equation. There is an interesting connection of this problem to laboratory experimental studies of particle transport in multi-mirror machines. The implications of the results are discussed. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.

Medvedev, Mikhail

2014-06-01

67

Relativistic heavy cosmic rays  

NASA Technical Reports Server (NTRS)

During three balloon flights of a 1 sq m sr ionization chamber/Cerenkov counter detector system, measurements were made of the atmospheric attenuation, flux, and charge composition of cosmic ray nuclei with 16 is less than or = Z is less than or = 30 and rigidity greater than 4.5 GV. The attenuation mean free path in air of VH (20 less than or = Z less than or = 30) nuclei is found to be 19.7 + or - 1.6 g/sq cm, a value somewhat greater than the best previous measurement. The attenuation mean free path of iron is found to be 15.6 + or - 2.2 g/sq cm, consistent with predictions of geometric cross-section formulae. An absolute flux of VH nuclei 10 to 20% higher than earlier experiments at similar geomagnetic cutoff and level of solar activity was measured. The relative abundances of even-charged nuclei are found to be in good agreement with results of other recent high resolution counter experiments. The observed cosmic ray chemical composition implies relative abundances at the cosmic ray source of Ca/Fe = 0.12 + or - 0.04 and S/Fe = 0.14 + or - 0.05.

Mewaldt, R. A.; Fernandez, J. I.; Israel, M. H.; Klarmann, J.; Binns, W. R.

1972-01-01

68

Do cosmic rays drive jets?  

E-print Network

A sudden release of high energy cosmic rays at the centre of a wind sustaining a spiral magnetic field produces cavities of low density and low magnetic field along the axis. The trajectories of high energy cosmic rays are focussed onto the axis, and lower energy cosmic rays and thermal plasma can escape through the cavities. This may explain the jets often seen in accretion systems and elsewhere.

A. R. Bell

2005-07-21

69

High energy cosmic rays: sources and fluxes  

NASA Astrophysics Data System (ADS)

We discuss the production of a unique energy spectrum of the high energy cosmic rays detected with air showers by shifting the energy estimates of different detectors. After such a spectrum is generated we fit the spectrum with three or four populations of cosmic rays that might be accelerated at different cosmic ray sources. We also present the chemical composition that the fits of the spectrum generates and discuss some new data sets presented this summer at the ICRC in Rio de Janeiro that may require new global fits.

Stanev, Todor; Gaisser, Thomas K.; Tilav, Serap

2014-04-01

70

Detecting Low-Contrast Features in the Cosmic Ray Albedo Proton Yield Map of the Moon  

NASA Astrophysics Data System (ADS)

High energy cosmic rays constantly bombard the lunar regolith, producing (via nuclear evaporation[1]) secondary 'albedo' or 'splash' particles like protons and neutrons, some of which escape back to space. Lunar Prospector and the Lunar Reconnaissance Orbiter (LRO), have shown that the energy distribution of albedo neutrons is modulated by the elemental composition of the lunar regolith[2-5], and by ice deposits[6] in permanently shadowed polar craters. Here we investigate an analogous phenomenon with high energy lunar albedo protons. Using the CRaTER instrument (Cosmic Ray Telescope for the Effects of Radiation) on LRO, we measure albedo protons (60 to 150 MeV) to construct a cosmic ray albedo proton map of the Moon. Our current map is a significant improvement over the proof-of-concept map of Wilson et al.[7]. In addition to using more numerous minimum ionizing GCR protons for normalization, we filter out all solar particle enhancement periods and make use of all six of CRaTER's detectors to reduce contamination from spurious non-proton events in the data stream. The average yield of albedo protons from the maria is 0.8% × 0.4% higher than the yield from the highlands. In addition there appear to be localized peaks in the albedo proton yield that are co-located with peaks in trace elemental abundances as measured by the Lunar Prospector Gamma Ray Spectrometer. More data may reveal subtler proton yield variations correlated with latitude, time of day, or the locations of permanently shadowed craters, due to the presence of water frost. Given that the most obvious features in the map have a proton yield only 2? above average, the search for more subtle regions of enhancement or reduction in proton yield will require precise corrections for small but systematic effects of time and spacecraft altitude on the apparent proton yield. We will show the effects of these trends as well as the latest version of the albedo proton map. References: [1] Bethe (1937) Rev. Mod. Phys., 9, 69. [2] Feldman W. C. et al. (1998) Science, 281, 1496-1500. [3] Gasnault, O. et al. (2001) GRL, 28, 3797-3800. [4] Maurice, S. et al. (2004) JGR, 109, E07S04. [5] Mitrofanov I. G. et al. (2010) Science, 330, 483-486. [6] Feldman W. C. et al. (1997) JGR, 102, 25565-25574. [7] Wilson, J. K. et al. (2012) JGR, 117, E00H23. Figure 1. Top: Color-coded lunar albedo proton map, with two high-yielding mare regions labeled 'A' and 'B'. Bottom: Clementine white-light mosaic of lunar surface.

Wilson, J. K.; Schwadron, N.; Spence, H.; Smith, S. S.; Golightly, M. J.; Case, A. W.; Stubbs, T. J.; Blake, J. B.; Kasper, J. C.; Looper, M. D.; Mazur, J. E.; Townsend, L. W.; Zeitlin, C. J.

2013-12-01

71

Cosmic Necklaces and Ultrahigh Energy Cosmic Rays  

SciTech Connect

Cosmic necklaces are hybrid topological defects consisting of monopoles and strings, with two strings attached to each monopole. We argue that the cosmological evolution of necklaces may significantly differ from that of cosmic strings. The typical velocity of necklaces can be much smaller than the speed of light, and the characteristic scale of the network much smaller than the horizon. We estimate the flux of high-energy protons produced by monopole annihilation in the decaying closed loops. For some reasonable values of the parameters it is comparable to the observed flux of ultrahigh-energy cosmic rays. {copyright} {ital 1997} {ital The American Physical Society}

Berezinsky, V. [INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi (Antarctica) (Italy)] [INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi (Antarctica) (Italy); Vilenkin, A. [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)] [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)

1997-12-01

72

Antiprotons in cosmic rays  

NASA Technical Reports Server (NTRS)

Recent experimental observations and results are discussed. It was found that the approximately 50 antiprotons collected in balloon experiments to date have generated considerable theoretical interest. Clearly, confirmatory experiments and measurements over an extended energy range are required before definite conclusions are drawn. Antiproton measurements have a bearing on astrophysical problems ranging from cosmic ray propagation to issues of cosmological import. The next generation of balloon experiments and the Particle Astrophysics Magnet Facility being discussed for operation on NASA's space station should provide data and insights of highest interest.

Balasubrahmanyan, V. K.; Ormes, J. F.; Streitmatter, R. E.

1987-01-01

73

The Origin of Cosmic Rays  

ScienceCinema

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

Pasquale Blasi

2010-01-08

74

The Origin of Cosmic Rays  

SciTech Connect

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the “end” of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform “cosmic ray astronomy”, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

Pasquale Blasi

2008-02-20

75

Gamma Ray Bursts from Ordinary Cosmic Strings  

E-print Network

We give an upper estimate for the number of gamma ray bursts from ordinary (non-superconducting) cosmic strings expected to be observed at terrestrial detectors. Assuming that cusp annihilation is the mechanism responsible for the bursts we consider strings arising at a GUT phase transition and compare our estimate with the recent BATSE results. Further we give a lower limit for the effective area of future detectors designed to detect the cosmic string induced flux of gamma ray bursts.

R. H. Brandenberger; A. T. Sornborger; M. Trodden

1993-02-12

76

The Nagoya cosmic-ray muon spectrometer  

Microsoft Academic Search

A cosmic-ray muon spectrometer using a solid iron magnet is now under construction. This spectrometer detects muon tracks optically by wide-gap spark chambers triggered by a time-of-flight counter system. The accuracy of the momentum determination of this spectrometer is estimated by a prototype experiment using eight small-scale spark chambers triggered by vertical cosmic-ray muons above 1 GeV\\/c. It is found

S. Shibata; Y. Kamiya; K. Kobayashi; S. Iida

1977-01-01

77

Cosmic Rays from Cosmic Strings with Condensates  

E-print Network

We re-visit the production of cosmic rays by cusps on cosmic strings. If a scalar field (``Higgs'') has a linear interaction with the string world-sheet, such as would occur if there is a bosonic condensate on the string, cusps on string loops emit narrow beams of very high energy Higgses which then decay to give a flux of ultra high energy cosmic rays. The ultra-high energy flux and the gamma to proton ratio agree with observations if the string scale is $\\sim 10^{13}$ GeV. The diffuse gamma ray and proton fluxes are well below current bounds. Strings that are {\\it lighter} and have linear interactions with scalars produce an excess of direct and diffuse cosmic rays and are ruled out by observations, while heavier strings ($\\sim 10^{15}$ GeV) are constrained by their gravitational signatures. This leaves a narrow window of parameter space for the existence of cosmic strings with bosonic condensates.

Tanmay Vachaspati

2009-11-24

78

An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays  

E-print Network

Experiments that observe coherent radio emission from extensive air showers induced by ultra-high energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100% up time as e.g. surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g. the Pierre Auger Observatory) as another type of air shower detector in addition to the fluorescence detectors, which operate with only ~10% of duty in dark nights. The radio signals from air showers are caused by the coherent emission due to geomagnetic radiation and charge excess processes. Currently used self-triggers in radio detectors often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data requires a significant man-power for the off-line analysis. An improvement of the trigger efficiency becomes a relevant factor. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for an optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not origin from cosmic ray showers but can be human-made contaminations. The engine of the wavelet analysis can be implemented into the modern powerful FPGA and can remove suspicious events on-line to reduce the trigger rate.

Zbigniew Szadkowski for the Pierre Auger Collaboration

2014-06-04

79

Cosmic Ray Positrons from Cosmic Strings  

E-print Network

We study the spectrum of cosmic ray positrons produced by a scaling distribution of non-superconducting cosmic strings. In this scenario, the positrons are produced from the jets which form from the cosmic string cusp annihilation process. The spectral shape is a robust feature of our scenario, and is in good agreement with the results from the recent PAMELA and ATIC experiments. In particular, the model predicts a sharp upper cutoff in the spectrum, and a flux which rises as the upper cutoff is approached. The energy at which the flux peaks is determined by the initial jet energy. The amplitude of the flux can be adjusted by changing the cosmic string tension and also depends on the cusp annihilation efficiency.

Robert Brandenberger; Yi-Fu Cai; Wei Xue; Xinmin Zhang

2009-01-25

80

Detection of transient ELF emission caused by the extremely intense cosmic gamma-ray flare of 27 December 2004  

NASA Astrophysics Data System (ADS)

We report on the first clear detection of transient Extremely-Low-Frequency (ELF) signal caused by an extremely intense cosmic gamma-ray flare. On 2004 December 27, the brightest gamma-ray flare ever recorded was observed by numerous satellites. A transient ELF emission observed at Moshiri and Onagawa in Japan exactly coincided with the peak time of the flare, and its wide pulse width of ˜40 ms disfavors the possibility of lightning origin. Furthermore, the two horizontal components of ELF magnetic field data recorded at Esrange in Sweden showed clear transient Schumann resonance waveforms. The source direction determined by the Lissajous method roughly corresponds to the subflare point. The chance probability that a sprite occurs within 30 ms of the peak flare time is ˜0.025%, which again clearly excludes the sprite origin. Thus, a bright cosmic gamma-ray flare is a new source of transient ELF radio signals observed on the Earth, although the emission mechanism needs to be clarified in future.

Tanaka, Y. T.; Hayakawa, M.; Hobara, Y.; Nickolaenko, A. P.; Yamashita, K.; Sato, M.; Takahashi, Y.; Terasawa, T.; Takahashi, T.

2011-04-01

81

Cosmic Ray Neutron Flux Measurements  

Microsoft Academic Search

Cosmic rays are high-energetic particles originating from outer space that bombard the upper atmosphere of the Earth. Almost 90% of cosmic ray particles consist of protons, electrons and heavy ions. When these particles hit the Earth's atmosphere, cascade of secondary particles are formed. The most abundant particles reach to the surface of the Earth are muons, electrons and neutrons. In

Mathes Dayananda

2009-01-01

82

Testing Galactic Cosmic Ray Models  

NASA Technical Reports Server (NTRS)

Models of the Galactic Cosmic Ray Environment are used for designing and planning space missions. The exising models will be reviewed. Spectral representations from these models will be compared with measurements of galactic cosmic ray spectra made on balloon flights and satellite flights over a period of more than 50 years.

Adams, James H., Jr.

2010-01-01

83

Cosmic Rays, Clouds, and Climate  

Microsoft Academic Search

It has been proposed that Earth's climate could be affected by changes in cloudiness caused by variations in the intensity of galactic cosmic rays in the atmosphere. This proposal stems from an observed correlation between cosmic ray intensity and Earth's average cloud cover over the course of one solar cycle. Some scientists question the reliability of the observations, whereas others,

K. S. Carslaw; R. G. Harrison; J. Kirkby

2002-01-01

84

Testing Galactic Cosmic Ray Models  

NASA Technical Reports Server (NTRS)

Models of the Galactic Cosmic Ray Environment are used for designing and planning space missions. The existing models will be reviewed. Spectral representations from these models will be compared with measurements of galactic cosmic ray spectra made on balloon flights and satellite flights over a period of more than 50 years.

Adams, James H., Jr.

2009-01-01

85

Superbubbles and Local Cosmic Rays  

NASA Technical Reports Server (NTRS)

We consider the possibility that distinctive features of the local cosmic ray spectra and composition are influenced by the Solar system being embedded within the cavity of an ancient superbubble. Shifts in the measured cosmic ray composition between 10(exp 11) and 10(exp 20) eV as well as the "knee" and "second knee" may be understood in this picture.

Streitmatter, Robert E.; Jones, Frank C.

2005-01-01

86

COSMIC-RAY TRANSPORT AND ANISOTROPIES  

SciTech Connect

We show that the large-scale cosmic-ray anisotropy at {approx}10 TeV can be explained by a modified Compton-Getting effect in the magnetized flow field of old supernova remnants. Cosmic rays arrive isotropically to the flow field and are then carried along with the flow to produce a large-scale anisotropy in the arrival direction. This approach suggests an optimum energy scale for detecting the anisotropy. Two key assumptions are that propagation is based on turbulence following a Kolmogorov law and that cosmic-ray interactions are dominated by transport via cosmic-ray-excited magnetic irregularities through the stellar wind of an exploding star and its shock shell. A prediction is that the amplitude is smaller at lower energies due to incomplete sampling of the velocity field and also smaller at larger energies due to smearing.

Biermann, Peter L. [MPI for Radioastronomy, Auf dem Huegel 69, D-53121 Bonn (Germany); Becker Tjus, Julia; Mandelartz, Matthias [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik I, D-44780 Bochum (Germany); Seo, Eun-Suk [Department of Physics, University of Maryland, College Park, MD 20742 (United States)

2013-05-10

87

Cosmic ray source abundances and the acceleration of cosmic rays  

NASA Astrophysics Data System (ADS)

The galactic cosmic ray elemental source abundances display a fractionation that is possibly based on first ionization potential (FIP) or volatility. A few elements break the general correlation of FIP and volatility and the abundances of these may help to distinguish between models for the origin of the cosmic ray source material. Data from the Cosmic Ray Isotope Spectrometer instrument on NASA's Advanced Composition Explorer spacecraft were used to derive source abundances for several of these elements (Na, Cu, Zn, Ga, Ge). Three (Na, Cu, Ge) show depletions which could be consistent with a volatility-based source fractionation model. .

George, J. S.; Wiedenbeck, M. E.; Barghouty, A. F.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Hink, P. L.; Klarmann, J.; Leske, R. A.; Lijowski, M.; Mewaldt, R. A.; Stone, E. C.; von Rosenvinge, T. T.; Yanasak, N. E.

2000-09-01

88

Cosmic rays in the heliosphere  

NASA Technical Reports Server (NTRS)

The different types of cosmic ray particles and their role in the heliosphere are briefly described. The rates of various energetic particles were examined as a function of time and used to derive various differential energy gradients. The Pioneer and Voyager cosmic ray observations throughout the heliosphere are indeed giving a perspective on the three-dimensional character and size of the heliosphere. Most clearly the observations are emphasizing the role that transient variations in the outer heliosphere, and most likely the heliospheric boundary shock, play in the 11 year solar cycle modulation of cosmic rays.

Webber, William R.

1987-01-01

89

Hydrodynamics of interstellar medium including cosmic rays  

Microsoft Academic Search

A relatively high pressure of cosmic rays in the interstellar medium causes noticeable dynamic effects. A system of MHD equations, that takes into account the action of cosmic rays, is discussed. The influence of cosmic rays on the stability of hydrostatic equilibrium of galactic halo is considered. The interaction between long hydromagnetic waves and cosmic rays is analyzed.

V. S. Ptuskin

1986-01-01

90

Hydrodynamics of interstellar medium including cosmic rays  

NASA Astrophysics Data System (ADS)

A relatively high pressure of cosmic rays in the interstellar medium causes noticeable dynamic effects. A system of MHD equations, that takes into account the action of cosmic rays, is discussed. The influence of cosmic rays on the stability of hydrostatic equilibrium of galactic halo is considered. The interaction between long hydromagnetic waves and cosmic rays is analyzed.

Ptuskin, V. S.

1986-08-01

91

Cosmic rays are on the air Studying the properties of radio signals from cosmic-ray  

E-print Network

Cosmic rays are on the air Studying the properties of radio signals from cosmic-ray induced air showers #12;#12;Cosmic rays are on the air Studying the properties of radio signals from cosmic-ray;#12;Contents 1 Introduction 1 1.1 Discovery of cosmic rays . . . . . . . . . . . . . . . . . . . . . . . 1 1

van Suijlekom, Walter

92

Galactic Cosmic Rays: From Earth to Sources  

NASA Technical Reports Server (NTRS)

For nearly 100 years we have known that cosmic rays come from outer space, yet proof of their origin, as well as a comprehensive understanding of their acceleration, remains elusive. Direct detection of high energy (up to 10(exp 15)eV), charged nuclei with experiments such as the balloon-born, antarctic Trans-Iron Galactic Element Recorder (TIGER) have provided insight into these mysteries through measurements of cosmic ray abundances. The abundance of these rare elements with respect to certain intrinsic properties suggests that cosmic rays include a component of massive star ejecta. Supernovae and their remnants (SNe & SNRs), often occurring at the end of a massive star's life or in an environment including massive star material, are one of the most likely candidates for sources accelerating galactic comic ray nuclei up to the requisite high energies. The Fermi Gamma-ray Space Telescope Large Area Detector (Fermi LAT) has improved our understanding of such sources by widening the window of observable energies and thus into potential sources' energetic processes. In combination with multiwavelength observations, we are now better able to constrain particle populations (often hadron-dominated at GeV energies) and environmental conditions, such as the magnetic field strength. The SNR CTB 37A is one such source which could contribute to the observed galactic cosmic rays. By assembling populations of SNRs, we will be able to more definitively define their contribution to the observed galactic cosmic rays, as well as better understand SNRs themselves. Such multimessenger studies will thus illuminate the long-standing cosmic ray mysteries, shedding light on potential sources, acceleration mechanisms, and cosmic ray propagation.

Brandt, Theresa J.

2012-01-01

93

Astrophysics of Galactic Charged Cosmic Rays  

NASA Astrophysics Data System (ADS)

A review is given of the main properties of the charged component of galactic cosmic rays, particles detected at Earth with an energy spanning from tens of MeV up to about 1019 eV. After a short introduction to the topic and a historical overview, the properties of cosmic rays are discussed with respect to different energy ranges. The origin and the propagation of nuclei in the Galaxy are dealt with from a theoretical point of view. The mechanisms leading to the acceleration of nuclei by supernova remnants and to their subsequent diffusion through the inhomogeneities of the galactic magnetic field are discussed, and some clue is given on the predictions and observations of fluxes of antimatter, both from astrophysical sources and from dark matter annihilation in the galactic halo.The experimental techniques and instrumentations employed for the detection of cosmic rays at Earth are described. Direct methods are viable up to ? 1014 eV, by means of experiments flown on balloons or satellites, while above that energy, due to their very low flux, cosmic rays can be studied only indirectly by exploiting the particle cascades they produce in the atmosphere.The possible physical interpretation of the peculiar features observed in the energy spectrum of galactic cosmic rays, and in particular the so-called "knee" at about 4 ×1015 eV, is discussed. A section is devoted to the region between about 1018 and 1019 eV, which is believed to host the transition between galactic and extragalactic cosmic rays. The conclusion gives some perspectives on the cosmic ray astrophysics field. Thanks to a wealth of different experiments, this research area is living a very flourishing era. The activity is exciting both from the theoretical and the instrumental sides, and its interconnection with astronomy, astrophysics, and particle physics experiences nonstop growth.

Castellina, Antonella; Donato, Fiorenza

94

30TH INTERNATIONAL COSMIC RAY CONFERENCE Detection of 2006 TeV-outburst of PKS 2155-304 with the CANGAROO-III telescope  

E-print Network

30TH INTERNATIONAL COSMIC RAY CONFERENCE Detection of 2006 TeV-outburst of PKS 2155-304@tkikam.sp.u-tokai.ac.jp Abstract: We present the detection of nearby BL Lacertae object PKS 2155-304 with the CANGAROO- III imaging 2006 July 28 and August 2. A signal from PKS2155-304 was detected at 5.7 level using the dataset

Enomoto, Ryoji

95

Gamma Ray Astronomy and the Origin of Galactic Cosmic Rays  

E-print Network

Diffusive shock acceleration operating at expanding supernova remnant shells is by far the most popular model for the origin of galactic cosmic rays. Despite the general consensus received by this model, an unambiguous and conclusive proof of the supernova remnant hypothesis is still missing. In this context, the recent developments in gamma ray astronomy provide us with precious insights into the problem of the origin of galactic cosmic rays, since production of gamma rays is expected both during the acceleration of cosmic rays at supernova remnant shocks and during their subsequent propagation in the interstellar medium. In particular, the recent detection of a number of supernova remnants at TeV energies nicely fits with the model, but it still does not constitute a conclusive proof of it, mainly due to the difficulty of disentangling the hadronic and leptonic contributions to the observed gamma ray emission. In this paper, the most relevant cosmic-ray-related results of gamma ray astronomy are briefly summarized, and the foreseeable contribution of future gamma ray observations to the final solution of the problem of cosmic ray origin is discussed.

Stefano Gabici

2008-11-05

96

High energy cosmic rays, gamma rays and neutrinos from AGN  

E-print Network

The author reviews a model for the emission of high energy cosmic rays, gamma-rays and neutrinos from AGN (Active Galactic Nuclei) that he has proposed since 1985. Further discussion of the knee energy phenomenon of the cosmic ray energy spectrum requires the existence of a heavy particle with mass in the knee energy range. A possible method of detecting such a particle in the Pierre Auger Project is suggested. Also presented is a relation between the spectra of neutrinos and gamma-rays emitted from AGN. This relation can be tested by high energy neutrino detectors such as ICECUBE, the Mediterranean Sea Detector and possibly by the Pierre Auger Project.

Yukio Tomozawa

2008-02-03

97

Anomalous cosmic rays  

NASA Astrophysics Data System (ADS)

Anomalous cosmic rays (ACRs) first started showing up in observations 40 years ago. Within a few years a paradigm was developed to explain their origin: they begin their life as interstellar neutral atoms that drift into the heliosphere, become singly ionized by chargeexchange with a solar wind ion or by photoionization, are picked up by the expanding solar wind, and accelerated to the observed energies by diffusive shock acceleration at the solar wind termination shock. This paradigm became widely accepted and withstood the tests of further observations until 16 December 2004, when Voyager 1 crossed the termination shock and didn't find their source. In August 2007, Voyager 2 crossed the termination shock and also did not find the source location of ACRs. Clearly, the source location was not at the termination shock where the two Voyagers crossed. Alternative models have been proposed with acceleration elsewhere on the shock or by other acceleration processes in the heliosheath. We discuss the latest observations of ACRs from the Voyager spacecraft and hopefully shed more light on this ongoing puzzle.

Cummings, Alan C.; Stone, Edward C.

2013-02-01

98

Investigation of primary cosmic rays at the Moon's surface  

SciTech Connect

The possibility of experimentally studying primary cosmic rays at the Moon's surface is considered. A mathematical simulations of showers initiated in the lunar regolith by high-energy particles of primary cosmic rays is performed. It is shown that such particles can in principle be recorded by simultaneously detecting three components of backscattered radiation (secondary neutrons, gamma rays, and radio emission).

Kalmykov, N. N., E-mail: kalm@eas.sinp.msu.ru; Konstantinov, A. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)] [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Muhamedshin, R. A. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)] [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Podorozhniy, D. M.; Sveshnikova, L. G.; Turundaevskiy, A. N. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)] [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Tkachev, L. G. [Joint Institute for Nuclear Research (Russian Federation)] [Joint Institute for Nuclear Research (Russian Federation); Chubenko, A. P. [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation)] [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation); Vasilyev, O. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)] [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2013-01-15

99

LARGE-SCALE DISTRIBUTION OF ARRIVAL DIRECTIONS OF COSMIC RAYS DETECTED ABOVE 10{sup 18} eV AT THE PIERRE AUGER OBSERVATORY  

SciTech Connect

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10{sup 18} eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declination and right ascension in several energy ranges above 10{sup 18} eV, and reported in terms of dipolar and quadrupolar coefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming that any cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits on their amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 10{sup 18} eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.

Abreu, P.; Andringa, S. [LIP and Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Universita di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Albuquerque, I. F. M. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Universite Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atomico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Facultad Regional Buenos Aires, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Alvarez Castillo, J. [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico); Alvarez-Muniz, J. [Universidad de Santiago de Compostela (Spain); Alves Batista, R. [IFGW, Universidade Estadual de Campinas, Campinas, SP (Brazil); Ambrosio, M.; Aramo, C. [Universita di Napoli 'Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici'c, T. [Rudjer Boskovi'c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Collaboration: Pierre Auger Collaboration; and others

2012-12-15

100

Irradiated ISM: Discriminating between Cosmic Rays and X-rays  

E-print Network

The ISM of active galaxy centers is exposed to a combination of cosmic ray, FUV and X-ray radiation. We apply PDR models to this ISM with both `normal' and highly elevated (5\\times 10^{-15}s^-1) cosmic-ray rates and compare the results to those obtained for XDRs. Our existing PDR-XDR code is used to construct models over a 10^3-10^5 cm^-3 density range and for 0.16-160 erg s^-1 cm^-2 impingent fluxes. We obtain larger high J (J>10) CO ratios in PDRs when we use the highly elevated cosmic ray rate, but these are always exceeded by the corresponding XDR ratios. The [CI] 609 mum/13CO(2-1) line ratio is boosted by a factor of a few in PDRs with n~10^3 cm^-3 exposed to a high cosmic ray rate. At higher densities ratios become identical irrespective of cosmic ray flux, while XDRs always show elevated [CI] emission per CO column. The HCN/CO and HCN/HCO+ line ratios, combined with high J CO emission lines, are good diagnostics to distinguish between PDRs under either low or high cosmic ray irradiation conditions, and XDRs. Hence, the HIFI instrument on Herschel, which can detect these CO lines, will be crucial in the study of active galaxies.

R. Meijerink; M. Spaans; F. P. Israel

2006-09-07

101

Lunar/Solar effects on Cosmic Rays  

E-print Network

Lunar/Solar effects on Cosmic Rays By: Sophia Bauer & Jenna Valdez #12;Introduction When cosmic be less cosmic rays coming into the earth's atmosphere from the direction of the moon. We were interested in if the moon has an effect on the number of cosmic rays, and therefore muons that make it to the earth

California at Santa Cruz, University of

102

Catching Cosmic Rays with a DSLR  

ERIC Educational Resources Information Center

Cosmic rays are high-energy particles from outer space that continually strike the Earth's atmosphere and produce cascades of secondary particles, which reach the surface of the Earth, mainly in the form of muons. These particles can be detected with scintillator detectors, Geiger counters, cloud chambers, and also can be recorded with commonly…

Sibbernsen, Kendra

2010-01-01

103

Monopole annihilation and highest energy cosmic rays  

SciTech Connect

Cosmic rays with energies exceeding 10[sup 20] eV have been detected. The origin of these highest energy cosmic rays remains unknown. Established astrophysical acceleration mechanisms encounter severe difficulties in accelerating particles to these energies. Alternative scenarios where these particles are created by the decay of cosmic topological defects have been suggested in the literature. In this paper we study the possibility of producing the highest energy cosmic rays through a process that involves the formation of metastable magnetic monopole-antimonopole bound states and their subsequent collapse. The annihilation of the heavy monopole-antimonopole pairs constituting the monopolonia can produce energetic nucleons, [gamma] rays, and neutrinos whose expected flux we estimate and discuss in relation to experimental data so far available. The monopoles we consider are the ones that could be produced in the early Universe during a phase transition at the grand unification energy scale. We find that observable cosmic ray fluxes can be produced with monopole abundances compatible with present bounds.

Bhattacharjee, P. (Isaac Newton Institute, University of Cambridge, 20 Clarkson Road, Cambridge CB3 0EH (United Kingdom) Indian Institute of Astrophysics, Sarjapur Road, Koramangala, Bangalore 560 034 (India)); Sigl, G. (Department of Astronomy Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637-1433 (United States) NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States))

1995-04-15

104

The origin of cosmic rays  

E-print Network

The search for the origin of cosmic rays is a quest of almost a hundred years. A recent theoretical proposal gives quantitative predictions, which can be tested with data. Specifically, it has been suggested, that all cosmic rays can be attributed to just three source sites: i) supernova explosions into the interstellar medium, ii) supernova explosions into a stellar wind, and iii) powerful radiogalaxies. The cosmic rays from any extragalactic source suffer from interaction with the microwave background, leading to the Greisen-Zatsepin-Kuzmin cutoff. While the particle energies, the spectrum and the chemical composition of cosmic rays over the energy range from about GeV to about 100 EeV can be interpreted in the theory, there are exciting measurements now: New measurements show that there are cosmic ray events beyond the Greisen-Zatsepin-Kuzmin cutoff. We discuss here possible sources, and specifically ask whether powerful radiogalaxies are suitable candidates. The basic concepts used here are the minimal hypothesis that the intergalactic magnetic field is given by the galaxy distribution, and the observation that radio galaxies also cluster like galaxies.

Peter L. Biermann

1995-01-04

105

Cosmic Rays and Sunspot Numbers  

NSDL National Science Digital Library

In this activity students analyze and compare two or more graphs to determine if there is a correlation between sunspot number and the variation of cosmic ray flux. They discover that cosmic rays are very energetic particles, mostly protons and electrons, that enter the solar system from the depths of interstellar space and that although the Earth's magnetic field partially shields us from these particles, so too does the much more extended solar wind with its own magnetic field. This is a three-part lesson in which students will construct line graphs displaying the cosmic ray flux and sunspot numbers for a period of time, and then determine if there is a correlation. In order to compare these two sets of data, students will need to scale the data in order to visualize the results. Teacher and student notes for the graphing calculator are included.

Susan Higley

106

Asymmetric diffusion of cosmic rays  

E-print Network

Cosmic ray propagation is diffusive because of pitch angle scattering by waves. We demonstrate that if the high-amplitude magnetohydrodynamic turbulence with $\\tilde B/\\langle B\\rangle \\sim 1$ is present on top of the mean field gradient, the diffusion becomes asymmetric. As an example, we consider the vertical transport of cosmic rays in our Galaxy propagating away from a point-like source. We solve this diffusion problem analytically using a one-dimensional Markov chain analysis. We obtained that the cosmic ray density markedly differs from the standard diffusion prediction and has a sizable effect on their distribution throughout the galaxy. The equation for the continuous limit is also derived, which shows limitations of the convection-diffusion equation.

Medvedev, Mikhail V

2015-01-01

107

Cosmic Rays above the Knee  

E-print Network

An overview on the present observational status and phenomenological understanding of cosmic rays above 10^16 eV is given. Above these energies the cosmic ray flux is expected to be gradually dominated by an extra-galactic component. In order to investigate the nature of this transition, current experimental activities focus on the measurement of the cosmic ray flux and composition at the 'ankle' or 'dip' feature at several EeV. At the ultra high energy end of the spectrum, the flux suppression above 50 EeV is now well established by the measurements of HiRes and the Pierre Auger Observatory and we may enter the era of charged particle astronomy.

Michael Unger

2008-12-15

108

The Lateral Trigger Probability function for the UltraHigh Energy Cosmic Ray showers detected by the Pierre Auger Observatory  

Microsoft Academic Search

In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an Extensive Air Shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface

P. Abreu; M. Aglietta; E. J. Ahn; I. F. M. Albuquerque; D. Allard; I. Allekotte; J. Allen; P. Allison; J. Alvarez Castillo; M. Ambrosio; A. Aminaei; L. Anchordoqui; S. Andringa; T. Anti?i?; A. Anzalone; C. Aramo; E. Arganda; F. Arqueros; H. Asorey; P. Assis; J. Aublin; M. Avenier; G. Avila; T. Bäcker; M. Balzer; K. B. Barber; A. F. Barbosa; R. Bardenet; S. L. C. Barroso; B. Baughman; J. Bäuml; J. J. Beatty; B. R. Becker; K. H. Becker; A. Bellétoile; J. A. Bellido; S. BenZvi; C. Berat; X. Bertou; P. L. Biermann; P. Billoir; F. Blanco; M. Blanco; H. Blümer; M. Bohá?ová; D. Boncioli; C. Bonifazi; R. Bonino; N. Borodai; J. Brack; P. Brogueira; W. C. Brown; R. Bruijn; P. Buchholz; A. Bueno; R. E. Burton; K. S. Caballero-Mora; L. Caramete; R. Caruso; A. Castellina; O. Catalano; G. Cataldi; L. Cazon; R. Cester; J. Chauvin; S. H. Cheng; A. Chiavassa; J. A. Chinellato; J. Chudoba; R. W. Clay; M. R. Coluccia; F. Contreras; H. Cook; M. J. Cooper; A. Cordier; U. Cotti; S. Coutu; C. E. Covault; A. Creusot; J. Cronin; A. Curutiu; S. Dagoret-Campagne; R. Dallier; S. Dasso; K. Daumiller; B. R. Dawson; R. M. de Almeida; C. De Donato; S. J. de Jong; G. De La Vega; I. De Mitri; V. de Souza; K. D. de Vries; G. Decerprit; L. del Peral; O. Deligny; H. Dembinski; N. Dhital; C. Di Giulio; J. C. Diaz; M. L. D?´az Castro; P. N. Diep; C. Dobrigkeit; W. Docters; J. C. D’Olivo; P. N. Dong; A. Dorofeev; J. C. dos Anjos; M. T. Dova; D. D’Urso; I. Dutan; J. Ebr; R. Engel; M. Erdmann; C. O. Escobar; A. Etchegoyen; P. Facal San Luis; I. Fajardo Tapia; H. Falcke; G. Farrar; A. C. Fauth; N. Fazzini; A. P. Ferguson; A. Ferrero; B. Fick; A. Filevich; S. Fliescher; C. E. Fracchiolla; U. Fröhlich; B. Fuchs; R. Gaior; R. F. Gamarra; S. Gambetta; B. Garc?´a; D. Garc?´a Gámez; D. García Gámez; A. Gascon; H. Gemmeke; K. Gesterling; P. L. Ghia; U. Giaccari; M. Giller; H. Glass; M. S. Gold; G. Golup; F. Gomez Albarracin; M. Gómez Berisso; P. Gonçalves; D. Gonzalez; J. G. Gonzalez; B. Gookin; D. Góra; A. Gorgi; P. Gouffon; S. R. Gozzini; E. Grashorn; S. Grebe; N. Griffith; M. Grigat; A. F. Grillo; Y. Guardincerri; F. Guarino; G. P. Guedes; A. Guzman; J. D. Hague; P. Hansen; D. Harari; S. Harmsma; J. L. Harton; A. Haungs; T. Hebbeker; D. Heck; A. E. Herve; C. Hojvat; N. Hollon; V. C. Holmes; P. Homola; J. R. Hörandel; A. Horneffer; M. Hrabovský; T. Huege; A. Insolia; F. Ionita; A. Italiano; C. Jarne; S. Jiraskova; K. Kadija; K. H. Kampert; P. Karhan; B. Kégl; B. Keilhauer; A. Keivani; J. L. Kelley; E. Kemp; R. M. Kieckhafer; H. O. Klages; M. Kleifges; J. Kleinfeller; D.-H. Koang; K. Kotera; N. Krohm; O. Krömer; D. Kruppke-Hansen; F. Kuehn; D. Kuempel; J. K. Kulbartz; N. Kunka; G. La Rosa; C. Lachaud; P. Lautridou; M. S. A. B. Leão; D. Lebrun; P. Lebrun; M. A. Leigui de Oliveira; A. Letessier-Selvon; I. Lhenry-Yvon; K. Link; R. López; A. Lopez Agüera; K. Louedec; J. Lozano Bahilo; A. Lucero; M. Ludwig; H. Lyberis; M. C. Maccarone; S. Maldera; D. Mandat; P. Mantsch; A. G. Mariazzi; J. Marin; V. Marin; I. C. Maris; H. R. Marquez Falcon; G. Marsella; D. Martello; L. Martin; H. Martinez; O. Mart?´nez Bravo; H. J. Mathes; J. A. J. Matthews; G. Matthiae; D. Maurizio; P. O. Mazur; G. Medina-Tanco; M. Melissas; D. Melo; E. Menichetti; A. Menshikov; P. Mertsch; C. Meurer; S. Mi?anovi?; M. I. Micheletti; W. Miller; L. Miramonti; S. Mollerach; M. Monasor; D. Monnier Ragaigne; F. Montanet; B. Morales; C. Morello; E. Moreno; J. C. Moreno; M. Mostafá; C. A. Moura; S. Mueller; M. A. Muller; G. Müller; M. Münchmeyer; R. Mussa; G. Navarra; J. L. Navarro; S. Navas; P. Necesal; L. Nellen; A. Nelles; P. T. Nhung; L. Niemietz; N. Nierstenhoefer; D. Nitz; D. Nosek; L. Nožka; M. Nyklicek; J. Oehlschläger; A. Olinto; P. Oliva; V. M. Olmos-Gilbaja; N. Pacheco; D. Pakk Selmi-Dei; M. Palatka; J. Pallotta; N. Palmieri; G. Parente; E. Parizot; A. Parra; R. D. Parsons; S. Pastor; T. Paul; M. Pech; R. Pelayo; I. M. Pepe; L. Perrone; R. Pesce; E. Petermann; S. Petrera; P. Petrinca; A. Petrolini; Y. Petrov; J. Petrovic; C. Pfendner; N. Phan; R. Piegaia; T. Pierog; P. Pieroni; M. Pimenta; V. Pirronello; M. Platino; V. H. Ponce; M. Pontz; P. Privitera; M. Prouza; E. J. Quel; S. Querchfeld; J. Rautenberg; O. Ravel; D. Ravignani; B. Revenu; J. Ridky; S. Riggi; M. Risse; P. Ristori; H. Rivera; V. Rizi; J. Roberts; C. Robledo; W. Rodrigues de Carvalho; G. Rodriguez; J. Rodriguez Martino; I. Rodriguez-Cabo; M. D. Rodr?´guez-Fr?´as; G. Ros; J. Rosado; T. Rossler; M. Roth; B. Rouillé-d’Orfeuil; E. Roulet; A. C. Rovero; F. Salamida; H. Salazar; G. Salina; F. Sánchez; M. Santander; C. E. Santo; E. M. Santos; F. Sarazin; B. Sarkar; S. Sarkar; R. Sato; N. Scharf; V. Scherini; H. Schieler; P. Schiffer; A. Schmidt; F. Schmidt; T. Schmidt; O. Scholten; H. Schoorlemmer; J. Schovancova

2011-01-01

109

The microphysics and macrophysics of cosmic rays  

SciTech Connect

This review paper commemorates a century of cosmic ray research, with emphasis on the plasma physics aspects. Cosmic rays comprise only ?10{sup ?9} of interstellar particles by number, but collectively their energy density is about equal to that of the thermal particles. They are confined by the Galactic magnetic field and well scattered by small scale magnetic fluctuations, which couple them to the local rest frame of the thermal fluid. Scattering isotropizes the cosmic rays and allows them to exchange momentum and energy with the background medium. I will review a theory for how the fluctuations which scatter the cosmic rays can be generated by the cosmic rays themselves through a microinstability excited by their streaming. A quasilinear treatment of the cosmic ray–wave interaction then leads to a fluid model of cosmic rays with both advection and diffusion by the background medium and momentum and energy deposition by the cosmic rays. This fluid model admits cosmic ray modified shocks, large scale cosmic ray driven instabilities, cosmic ray heating of the thermal gas, and cosmic ray driven galactic winds. If the fluctuations were extrinsic turbulence driven by some other mechanism, the cosmic ray background coupling would be entirely different. Which picture holds depends largely on the nature of turbulence in the background medium.

Zweibel, Ellen G. [Departments of Astronomy and Physics and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)] [Departments of Astronomy and Physics and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2013-05-15

110

High-energy X-Ray Detection of G359.89-0.08 (Sgr A-E): Magnetic Flux Tube Emission Powered by Cosmic Rays?  

NASA Astrophysics Data System (ADS)

We report the first detection of high-energy X-ray (E > 10 keV) emission from the Galactic center non-thermal filament G359.89-0.08 (Sgr A-E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The bright filament was detected up to ~50 keV during a NuSTAR Galactic center monitoring campaign. The featureless power-law spectrum with a photon index ? ? 2.3 confirms a non-thermal emission mechanism. The observed flux in the 3-79 keV band is FX = (2.0 ± 0.1) × 10-12 erg cm-2 s-1, corresponding to an unabsorbed X-ray luminosity LX = (2.6 ± 0.8) × 1034 erg s-1 assuming a distance of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A-E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps TeV electrons. We propose two possible TeV electron sources: old PWNe (up to ~100 kyr) with low surface brightness and radii up to ~30 pc or MCs illuminated by cosmic rays (CRs) from CR accelerators such as SNRs or Sgr A*.

Zhang, Shuo; Hailey, Charles J.; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; Mori, Kaya; Nynka, Melania; Stern, Daniel; Tomsick, John A.; Zhang, William W.

2014-03-01

111

High-Energy X-Ray Detection of G359.89-0.08 (SGR A-E): Magnetic Flux Tube Emission Powered by Cosmic Rays?  

NASA Technical Reports Server (NTRS)

We report the first detection of high-energy X-ray (E (is) greater than 10 keV) emission from the Galactic center non-thermal filament G359.89-0.08 (Sgr A-E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The bright filament was detected up to approximately 50 keV during a NuSTAR Galactic center monitoring campaign. The featureless power-law spectrum with a photon index gamma approximately equals 2.3 confirms a non-thermal emission mechanism. The observed flux in the 3-79 keV band is F(sub X) = (2.0 +/- 0.1) × 10(exp -12)erg cm(-2) s(-1) , corresponding to an unabsorbed X-ray luminosity L(sub X) = (2.6+/-0.8)×10(exp 34) erg s(-1) assuming a distance of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A-E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps TeV electrons. We propose two possible TeV electron sources: old PWNe (up to (is) approximately 100 kyr) with low surface brightness and radii up to (is) approximately 30 pc or MCs illuminated by cosmic rays (CRs) from CR accelerators such as SNRs or Sgr A*.

Zhang, Shuo; Hailey, Charles J.; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; Mori, Kaya; Nynka, Melania; Stern, Daniel; Tomsick, John A; Zhang, Will

2014-01-01

112

Cosmic rays at fluid discontinuities  

NASA Technical Reports Server (NTRS)

Cosmic-ray transport near discontinuities in the background fluid velocity is considered. Matching conditions for the cosmic-ray distribution are derived for both shear and compressive (shock) discontinuities, keeping terms to second order in the ratio of fluid speed to energetic-particle speed. Acceleration is found at shear discontinuities, which is not present in the first-order theory, and a modification of the matching condition at shocks. If there is no particle source concentrated at a shock, the new condition reduces to that obtained from first-order theory. Monte Carlo simulations show good agreement with the theory.

Jokipii, J. R.; Kota, J.; Morfill, G.

1989-01-01

113

Fun Times with Cosmic Rays  

NASA Technical Reports Server (NTRS)

Who would have thought cosmic rays could be so hip? Although discovered 90 years ago on death-defying manned balloon flights hip even by twenty-first-century extremesport standards cosmic rays quickly lost popularity as way-cool telescopes were finding way-too-cool phenomena across the electromagnetic spectrum. Yet cosmic rays are back in vogue, boasting their own set of superlatives. Scientists are tracking them down with new resolve from the Arctic to Antarctica and even on the high western plains of Argentina. Theorists, too, now see cosmic rays as harbingers of funky physics. Cosmic rays are atomic and subatomic particles - the fastest moving bits of matter in the universe and the only sample of matter we have from outside the solar system (with the exception of interstellar dust grains). Lower-energy cosmic rays come from the Sun. Mid-energy particles come from stellar explosions - either spewed directly from the star like shrapnel, or perhaps accelerated to nearly the speed of light by shock waves. The highest-energy cosmic rays, whose unequivocal existence remains one of astronomy's greatest mysteries, clock in at a staggering 10(exp 19) to 10(exp 22) electron volts. This is the energy carried in a baseball pitch; seeing as how there are as many atomic particles in a baseball as there are baseballs in the Moon, that s one powerful toss. No simple stellar explosion could produce them. At a recent conference in Albuquerque, scientists presented the first observational evidence of a possible origin for the highest-energy variety. A team led by Elihu Boldt at NASA s Goddard Space Flight Center found that five of these very rare cosmic rays (there are only a few dozen confirmed events) come from the direction of four 'retired' quasar host galaxies just above the arm of the Big Dipper, all visible with backyard telescopes: NGC 3610, NGC 3613, NGC 4589, and NGC 5322. These galaxies are billions of years past their glory days as the brightest beacons in the universe. Yet they still harbor central, supermassive black holes, which could generate energetic particles if they are spinning.

Wanjek, Christopher

2003-01-01

114

The cosmic ray source composition  

NASA Technical Reports Server (NTRS)

The cosmic ray source composition is shown to be related to the observed cosmic ray abundances by a set of linear equations which are valid for either ad hoc pathlength distributions or quantitative solutions to Galactic propagation models. These relations can be used to propagate abundances from the source or to the source, and the method described here allows a simple propagation of abundance uncertainties. A simultaneous analysis of B/C and (21-25)Fe indicates a need for truncation of the pathlength distribution.

Margolis, S. H.

1983-01-01

115

Measurement of the Flux of Cosmic Ray Muons  

Microsoft Academic Search

We have constructed a scintillation system that is able to detect cosmic- ray muons with energy above a certain threshold. Some old equipment from CERN was brought back to working order, and a new electronic l- tering system was made to deal with the bad state of some of the recycled parts. The detector was used to measure the cosmic-ray

Yohai Meiron

116

Nineteenth International Cosmic Ray Conference. SH Sessions, Volume 5  

NASA Technical Reports Server (NTRS)

Papers submitted for presentation at the 19th International Cosmic Ray Conference are compiled. This volume contains papers addressing cosmic ray gradients in the heliosphere; siderial, diurnal, and long term modulations; geomagnetic and atmospheric effects; cosmogenic nuclides; solar neutrinos; and detection techniques.

Jones, F. C. (compiler)

1985-01-01

117

Cosmic Rays and Space Situational Awareness in Europe  

Microsoft Academic Search

In this paper European space weather activities are sketched and the contribution of cosmic ray research and technology to the European space situational awareness programme is described. Especially the cosmic ray muon detection technique is studied - on ground and in future space based -, because it is considered to be very useful for coronal mass ejection forecast in the

F. Jansen; J. Behrens

118

Muon Charge Ratio of Ultrahigh Energy Cosmic Rays  

E-print Network

The muon charge ratio of ultrahigh energy cosmic rays may provide information to detect the composition of the primary cosmic rays. We propose to extract the charge information of high energy muons in very inclined extensive air showers by analyzing their relative lateral positions in the shower transverse plane.

Bo-Qiang Ma

2008-08-19

119

High Energy Cosmic Rays  

E-print Network

Cloud chambers emulsion #12;T.Hebbeker Neutrino Oscillations Super- Kamiokande CerenkovA + Atmosphere ? Influence on climate ? Charged particles = seeds for condensation cloud chamber Cosmics Leaving OUtdoor 011 012 013 014 015 016 017 018 019 020 02 02 017 018 019 020 CMS muon chamber Aachen 2002 4 cm #12

Hebbeker, Thomas

120

Evaluation of Galactic Cosmic Ray Models  

NASA Technical Reports Server (NTRS)

Models of the galactic cosmic ray spectra have been tested by comparing their predictions to an evaluated database containing more than 380 measured cosmic ray spectra extending from 1960 to the present.

Adams, James H., Jr.; Heiblim, Samuel; Malott, Christopher

2009-01-01

121

Frontiers of Cosmic Ray Science 205 Long-Term Variations of Cosmic Rays and Terrestrial  

E-print Network

Frontiers of Cosmic Ray Science 205 Long-Term Variations of Cosmic Rays and Terrestrial Environmentth International Cosmic Ray Conference (August 2003, Tsukuba, Japan): SH 3.4 "Long-term variations," SH 3.5 "Long-term variation of cosmic rays studied by cosmogenic nuclides," SH 3.6 "Terrestrial

Usoskin, Ilya G.

122

Cosmic-Ray Detectors With Interdigitated Electrodes  

NASA Technical Reports Server (NTRS)

Detectors measure both positions of incidence and energies of incident charged particles. Stack of detector wafers intercept cosmic ray. Measure positions of incidence to determine cosmic-ray trajectory and charge generated within them (proportional to cosmic-ray energy dissipated within them). Interdigital electrode pattern repeated over many rows and columns on tops of detector wafers in stack. Electrode pattern defines pixels within which points of incidence of incident cosmic rays located.

Cunningham, Thomas J.; Mazed, Mohammed; Holtzman, Melinda J.; Fossum, Eric R.

1995-01-01

123

Cosmic-ray-veto detector system  

NASA Astrophysics Data System (ADS)

To reduce the cosmic-ray-induced neutron background, we are testing a cosmic-ray veto option with a neutron detector system that uses plastic scintillator slabs mounted on the outside of a H-3-tube detector. The scintillator slabs eliminate unwanted cosmic-ray events, enabling the detector to assay low-level plutonium samples, for which a low-background coincident signature is critical. This report describes the design and testing of the prototype cosmic-ray-veto detector system.

Miller, D. W.; Menlove, H. O.

1992-12-01

124

28th International Cosmic Ray Conference 4065 The Cosmic Ray Shadows of the Moon and the Sun De-  

E-print Network

28th International Cosmic Ray Conference 4065 The Cosmic Ray Shadows of the Moon and the Sun De of the data shows that the shadows of the sun and moon have each been detected with high significances of the sun is significantly weaker than that of the moon. As expected, the measured positions of the deficits

California at Santa Cruz, University of

125

Modulation and diffusion theory of cosmic rays  

NASA Technical Reports Server (NTRS)

Papers given on the modulation of galactic cosmic rays by the solar wind at the 14th International Cosmic Ray Conference are reviewed. Some of the topics treated in this review are Pioneer and Helios radial gradient measurement, heliolatitude effects in modulation models, diffusion (scattering) theory - including pitch angle diffusion diagrams - solar flare particle transport theory and cosmic ray fluctuations at neutron monitor energies.

Forman, M. A.

1975-01-01

126

How Cosmic Rays Affect Learning Objectives  

E-print Network

1 CRaTER: How Cosmic Rays Affect Humans Learning Objectives: · Students will be able to describe why cosmic rays are dangerous to astronauts. · Studentswilllearntodesignascientificinstrument. · Students will think critically about how to protect astronauts from cosmic rays. Preparation: None

Christian, Eric

127

Research in cosmic and gamma ray astrophysics  

NASA Technical Reports Server (NTRS)

Discussed here is research in cosmic ray and gamma ray astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology. The primary activities discussed involve the development of new instrumentation and techniques for future space flight. In many cases these instrumentation developments were tested in balloon flight instruments designed to conduct new investigations in cosmic ray and gamma ray astrophysics. The results of these investigations are briefly summarized. Specific topics include a quantitative investigation of the solar modulation of cosmic ray protons and helium nuclei, a study of cosmic ray positron and electron spectra in interplanetary and interstellar space, the solar modulation of cosmic rays, an investigation of techniques for the measurement and interpretation of cosmic ray isotopic abundances, and a balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen.

Stone, Edward C.; Mewaldt, Richard A.; Prince, Thomas A.

1992-01-01

128

Cosmic gamma-ray bursts  

Microsoft Academic Search

The results of the observation of cosmic gamma-ray bursts are discussed and available theoretical models are presented. Emphasis is placed on a cosmological model in which a gamma burst results from a powerful (? 1051–1053 erg) and very short ( ?10 –100 s) energy release which occurs in a compact ( ? 106–107 cm) region and gives rise to a

Konstantin A Postnov

1999-01-01

129

The Cosmic Ray Electron Excess  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the possible sources for the apparent excess of Cosmic Ray Electrons. The presentation reviews the Advanced Thin Ionization Calorimeter (ATIC) instrument, the various parts, how cosmic ray electrons are measured, and shows graphs that review the results of the ATIC instrument measurement. A review of Cosmic Ray Electrons models is explored, along with the source candidates. Scenarios for the excess are reviewed: Supernova remnants (SNR) Pulsar Wind nebulae, or Microquasars. Each of these has some problem that mitigates the argument. The last possibility discussed is Dark Matter. The Anti-Matter Exploration and Light-nuclei Astrophysics (PAMELA) mission is to search for evidence of annihilations of dark matter particles, to search for anti-nuclei, to test cosmic-ray propagation models, and to measure electron and positron spectra. There are slides explaining the results of Pamela and how to compare these with those of the ATIC experiment. Dark matter annihilation is then reviewed, which represent two types of dark matter: Neutralinos, and kaluza-Kline (KK) particles, which are next explained. The future astrophysical measurements, those from GLAST LAT, the Alpha Magnetic Spectrometer (AMS), and HEPCAT are reviewed, in light of assisting in finding an explanation for the observed excess. Also the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) could help by revealing if there are extra dimensions.

Chang, J.; Adams, J. H.; Ahn, H. S.; Bashindzhagyan, G. L.; Christl, M.; Ganel, O.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kuznetsov, E. N.; Panasyuk, M. I.; Panov, A. D.; Schmidt, W. K. H.; Seo, E. S.; Sokolskaya, N. V.; Watts, J. W.; Wefel, J. P.; Wu, J.; Zatsepin, V. I.

2008-01-01

130

Cosmic rays and hadronic interactions  

SciTech Connect

The cosmic ray spectrum extends to particles with energy E{approx} 10{sup 20} eV, that corresponds (assuming that the primary particle is a proton) to a nucleon-nucleon c.m. energy {radical}(s) Asymptotically-Equal-To 430TeV, 50 times higher than the current LHC energy. These very high energy particles can be studied via the observation of the showers they generate in the atmosphere. The interpretation of the data requires therefore the modeling of hadronic interactions in an energy range beyond what can be studied in accelerator experiments. The theoretical problem of estimating the relevant properties of hadronic interactions in this energy range is therefore of central importance for the interpretation of the cosmic ray data. Viceversa, it is in principle possible to obtain information about hadronic interactions from the cosmic ray observations, but this program has to confront the fact that the (freely available) cosmic ray beam has an unknown energy spectrum and an unknown mass composition.

Lipari, Paolo [INFN sez. Roma, and Dipartimento di Fisica, Universita di Roma Sapienza (Italy)

2013-03-25

131

Cosmic Ray Energetics And Mass  

NASA Astrophysics Data System (ADS)

The 6 flights of the Cosmic Ray Energetics and Mass (CREAM) balloon payload over Antarctica accumulated 161 days of exposure. The instrument is configured with complementary and redundant particle detectors for direct measurements of high energy cosmic ray elemental spectra. The calorimeter and Silicon Charge Detectors (SCD) from one of the two instruments are being re-configured for the International Space Station, dubbed ISS-CREAM. The other calorimeter and detectors that are too large to fit in the ISS Japanese Experiment Module Exposed Facility envelope are kept for balloon flights. The large area Timing Charged Detector (TCD) and newly developed Transition Radiation Detector (TRD) will be used for studying the propagation history of cosmic rays by measuring relative abundances of secondary particles, e.g., Boron. This Boron and Carbon Cosmic Rays in the Upper Stratosphere (BACCUS) balloon payload will provide in-flight cross calibration of the calorimeter and TRD for Z > 3 particles. The status of the payload construction and flight preparation will be reported.

Seo, Eun-Suk

132

High-energy Cosmic Rays  

E-print Network

After a brief review of galactic cosmic rays in the GeV to TeV energy range, we describe some current problems of interest for particles of very high energy. Particularly interesting are two features of the spectrum, the `knee' above $10^{15}$ eV and the `ankle' above $10^{18}$ eV. An important question is whether the highest energy particles are of extra-galactic origin and, if so, at what energy the transition occurs. A theme common to all energy ranges is use of nuclear abundances as a tool for understanding the origin of the cosmic radiation.

Thomas K. Gaisser; Todor Stanev

2005-10-11

133

Cosmic Ray DetectorC. Little1,2, M. Barnett1, D. Chabot1, R. Igarashi1, T. Mavrichi1, R. Pywell1, W. Wurtz1 Cosmic Ray DetectorCosmic Ray DetectorC. Little1,2, M. Barnett1, D. Chabot1, R. Igarashi1, T. Mavrichi1, R. Pywell1, W. Wurtz1  

E-print Network

Cosmic Ray DetectorC. Little1,2, M. Barnett1, D. Chabot1, R. Igarashi1, T. Mavrichi1, R. Pywell1, W. Wurtz1 Cosmic Ray DetectorCosmic Ray DetectorC. Little1,2, M. Barnett1, D. Chabot1, R. Igarashi1, T. Mavrichi1, R. Pywell1, W. Wurtz1 Method of DetectionMethod of DetectionCosmic RaysCosmic Rays Why Detect

Saskatchewan, University of

134

Cosmic Rays and Gamma Ray Bursts From Microblazars  

E-print Network

Highly relativistic jets from merger and accretion induced collapse of compact stellar objects, which may produce the cosmological gamma ray bursts (GRBs), are also very efficient and powerful cosmic ray accelerators. The expected luminosity, energy spectrum and chemical composition of cosmic rays from Galactic GRBs, most of which do not point in our direction, can explain the observed properties of Galactic cosmic rays.

Arnon Dar

1998-09-13

135

Feasibility Studies of RADAR detection of Extensive Air Showers from Ultra-high Energy Cosmic Rays  

E-print Network

. Phenomena detectable by RADAR 17 IV. Meteor Science 19 10. Meteor Physics 19 10.1. Meteor Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 10.2. Ionisation Produced by Meteors . . . . . . . . . . . . . . . . . . . . . . . . 24 10.5. Comparison of Meteor and EAS generated Ionisation Columns . . . . . . . 27 iii #12;11. Meteor Scatter

Hebbeker, Thomas

136

Search for AntiparticleSearch for Antiparticle in Cosmic Raysin Cosmic Rays  

E-print Network

Search for AntiparticleSearch for Antiparticle in Cosmic Raysin Cosmic Rays with BESSwith BESS ·University of Denver J. Ormes, N. Thakur #12;CosmicCosmic--Ray Antiproton ChronologyRay Antiproton ChronologySearch for Primordial Antiparticles in CosmicAntiparticles in Cosmic RaysRays Primary origins relatively enhanced at

Yamamoto, Hirosuke

137

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1992-01-01

138

Earth's magnetic field as a radiator to detect cosmic ray electrons of energy greater than 10 to the 12th eV  

NASA Technical Reports Server (NTRS)

Synchrotron emission by a high-energy electron in the geomagnetic field and its dependence upon different arrival directions over Palestine, Texas, where major balloon-borne experiments are being conducted, is studied. The dependence of detector response on the arrival direction of electron, the different criteria which are adopted to identify an electron event, the area of the detector, and the energy of the electron are discussed. An omnidirectional circular detector is used to examine whether it is possible to determine the energy of an electron without knowing its arrival direction. The collecting power of a detector is estimated as a function of the energy of electrons for different detector areas with different selection criteria, and this information is used to calculate the event rates expected by folding in the energy spectrum of cosmic ray electrons to show the viability of detecting cosmic ray electrons at energies greater than a few TeV.

Balasubrahmanyan, V. K.; Stephens, S. A.

1983-01-01

139

Solar panels as cosmic-ray detectors  

E-print Network

Due to fundamental limitations of accelerators, only cosmic rays can give access to centre-of- mass energies more than one order of magnitude above those reached at the LHC. In fact, extreme energy cosmic rays (1018 eV - 1020 eV) are the only possibility to explore the 100 TeV energy scale in the years to come. This leap by one order of magnitude gives a unique way to open new horizons: new families of particles, new physics scales, in-depth investigations of the Lorentz symmetries. However, the flux of cosmic rays decreases rapidly, being less than one particle per square kilometer per year above 1019 eV: one needs to sample large surfaces. A way to develop large-effective area, low cost, detectors, is to build a solar panel-based device which can be used in parallel for power generation and Cherenkov light detection. Using solar panels for Cherenkov light detection would combine power generation and a non-standard detection device.

Stella, Carlo; Assis, Pedro; Brogueira, Pedro; Santo, Catarina Espirito; Goncalves, Patricia; Pimenta, Mario; De Angelis, Alessandro

2014-01-01

140

Neutrons and antiprotons in ultrahigh energy cosmic rays  

E-print Network

The neutron fraction in the very high energy cosmic rays near the Greisen-Zatsepin-Kuzmin (GZK) cutoff energy is analyzed by taking into account the time dilation effect of the neutron decays and also the pion photoproduction behaviors above the GZK cutoff. We predict a non-trivial neutron fraction above the GZK cutoff and a negligibly small neutron fraction below. However, there should be a large antiproton fraction in the high energy cosmic rays below the GZK cutoff in several existing models for the observed cosmic-ray events above and near the GZK cutoff. Such a large antiproton fraction can manifest itself by the muon charge ratio $\\mu^+/\\mu^-$ in the collisions of the primary nucleon cosmic rays with the atmosphere, if there is no neutron contribution. We suggest to use the muon charge ratio as one of the information to detect the composition of the primary cosmic rays near or below the GZK cutoff.

W-Y. P. Hwang; Bo-Qiang Ma

2005-09-06

141

Fractional diffusion of cosmic rays  

E-print Network

We consider the propagation of galactic cosmic rays under assumption that the interstellar medium is a fractal one. An anomalous diffusion equation in terms of fractional derivatives is used to describe of cosmic ray propagation. The anomaly in used model results from large free paths ("Levy flights") of particles between galactic inhomogeneities and long time a particle stays in a trap. An asymptotical solution of the anomalous diffusion equation for point instantaneous and impulse sources with inverse power spectrum relating to supernova bursts is found. It covers both subdiffusive and superdiffusive regimes and is expressed in terms of the stable distributions. The energy dependence of spectral exponent of observed particles in different regimes is discussed.

A. A. Lagutin; V. V. Uchaikin

2001-07-13

142

Cosmic ray penetration in diffuse clouds  

E-print Network

Cosmic rays are a fundamental source of ionization for molecular and diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of cosmic rays inside a cloud also determines the $\\gamma$-ray flux produced by hadronic collisions between cosmic rays and cloud material. We study the spectrum of cosmic rays inside and outside of a diffuse cloud, by solving the stationary transport equation for cosmic rays including diffusion, advection and energy losses due to ionization of neutral hydrogen atoms. We found that the cosmic ray spectrum inside a diffuse cloud differs from the one in the interstellar medium for energies smaller than $E_{br}\\approx 100$ MeV, irrespective of the model details. Below $E_{br}$, the spectrum is harder (softer) than that in the interstellar medium if the latter is a power law $\\propto p^{-s}$ with $s$ larger (smaller) than $\\sim0.42$.

Morlino, G

2015-01-01

143

Cosmic Rays Help Drive Galactic Winds  

NASA Astrophysics Data System (ADS)

Cosmic rays deposit both momentum and energy into thermal gas when magnetic fields are present (Wentzel, 1968; Kulsrud Pearce, 1969). Since we observe evidence of magnetic fields, cosmic-rays, and hot gas in galactic disks, it is plausible that cosmic rays may add momentum and energy to gas, and therefore help drive galactic-scale outflows. Building on past work by Breitschwerdt, Zirakashvili, Ptuskin, and others, our group investigates "hybrid" galactic winds driven by cosmic-ray and thermal-gas pressure. We have found that such a wind can fit mid-latitude Galactic X-ray emission observed by ROSAT towards the center of the Galaxy, and also (with some physically motivated modifications) fits radio-synchrotron survey data. We are now building estimates of the gamma-ray emission for this wind. So far, we also find that the parameters of such a wind are plausible for the conditions of the central Milky Way. More generally, we illustrate how cosmic-ray driving may increase the prevalance of galactic winds. For this talk, I will review the hydrodynamics of cosmic rays, including the work of other groups on cosmic-ray driven winds. I will highlight how cosmic ray pressure can help drive Galactic winds, how such a wind may work in our Galaxy, and include estimates of the impact of cosmic-ray diffusivity and the driving of cool clouds (observed within extragalactic winds and important to constrain wind velocities) within such a wind.

Everett, John; Zweibel, Ellen; Schiller, Quintin; Hu, Kaiqi

144

Cloud chamber visualization of primary cosmic rays  

SciTech Connect

From 1948 until 1963, cloud chambers were carried to the top of the atmosphere by balloons. From these flights, which were begun by Edward P. Ney at the University of Minnesota, came the following results: discovery of heavy cosmic ray nuclei, development of scintillation and cherenkov detectors, discovery of cosmic ray electrons, and studies of solar proton events. The history of that era is illustrated here by cloud chamber photographs of primary cosmic rays.

Earl, James A. [Department of Astronomy, University of Maryland, College Park MD (United States)

2013-02-07

145

Cosmic Rays 8.1 Composition and energy distribution  

E-print Network

Chapter 8 Cosmic Rays 8.1 Composition and energy distribution Cosmic rays can be broadly defined, and exotics (WIMPS, axions,...) striking the earth. The primary cosmic rays are those entering the upper atmosphere, the cosmic rays of the interstellar medium. Secondary cosmic rays are those produced

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

146

Observation of a rare cosmic ray event at mountain altitude  

NASA Astrophysics Data System (ADS)

Existence of strangelets in cosmic rays has been predicted even at mountain altitudes ?3-4 km with extremely low abundance. We exposed an appropriate passive detector to cosmic rays at Darjeeling, India, at an atmospheric pressure of 765 hPa, as a pilot study to determine its suitability for the detection of strangelets in a large area detector array through long-term exposure. During the analysis we found a highly unusual event consisting of a cluster of six identical nuclear tracks. We argue that even the most mundane explanation of this event requires unusual physics, the first possible observation of multifragmentation involving cosmic rays.

Basu, Basudhara; Raha, Sibaji; Saha, Swapan K.; Biswas, Sukumar; Dey, Sandhya; Maulik, Atanu; Mazumdar, Amal; Saha, Satyajit; Syam, Debapriyo

2015-02-01

147

Propagation of cosmic rays in the galaxy  

NASA Technical Reports Server (NTRS)

The characteristics of a model for analyzing the propagation of cosmic rays are discussed. The requirements for analyzing the relevant observational data on cosmic rays are defines as: (1) the chemical and isotopic composition of cosmic rays as a function of energy, (2) the flux and energy spectrum of the individual nucleonic components, (3) the flux and energy spectrum of the electronic component, (4) the cosmic ray prehistory, and (5) the degree of isotropy in their arrival directions as a function of energy. It is stated that the model which has been able to bring to pass the greatest measure of success is the galactic confinement model.

Daniel, R. R.; Stephens, S. A.

1974-01-01

148

Cosmic ray modulation by interplanetary disturbances  

NASA Astrophysics Data System (ADS)

Interplanetary disturbances such as ICMEs (Interplanetary Coronal Mass Ejections) and CIRs (Corotating Interaction Regions), modulate high-energy cosmic rays reaching the Earth. Prior to the arrival of the disturbances at the Earth, ground based high-energy muon detectors can detect precursory effects in cosmic-ray anisotropy, such as precursory deficit and/or excess of intensity along the sunward IMF (Interplanetary Magnetic Field) direction. With suitable analyses, these precursors are found typically around 8 hours prior to the disturbance arrival at the Earth. The objective of this work is to analyze these precursors by using the Global Muon Detector Network (GMDN), an international network formed by four multidirectional muon detectors viewing a full range of the pitch angle measured from the sunward IMF direction. By analyzing the variation of the count rate global distribution of the observed intensity (instead of analyzing the count rate) precursory signatures can be enhanced when compared with analyses of count rates. For some events, it is possible to make almost a global distribution map of cosmic ray density using all the directional channels of the detectors. Precursory signature is generally accompanied by the interplanetary shock, but there are also some signatures not associated with the shock.

Braga, Carlos Roberto; Dal Lago, Alisson; Schuch, Nelson Jorge; da Silva, Marlos; Echer, Ezequiel; Demítrio Gonzalez Alarcon, Walter; Munakata, Kazuoki; Kuwabara, Takao; Kato, Chihiro; Bieber, John W.

149

Cosmic Ray Energetics and Mass (CREAM)  

NASA Technical Reports Server (NTRS)

The CREAM instrument was flown on a Long Duration Balloon in Antarctica in December 2004 and January 2005, achieving a flight duration record of nearly 42 days. It detected and recorded cosmic ray primary particles ranging in type from hydrogen to iron nuclei and in energy from 1 TeV to several hundred TeV. With the data collected we will have the world's best measurement of the energy spectra and mass composition of nuclei in the primary cosmic ray flux at these energies, close to the astrophysical knee . The instrument utilized a thin calorimeter, a transition radiation detector and a timing charge detector, which also provided time-of-flight information. The responsibilities of our group have been with the timing charge detector (TCD), and with the data acquisition electronics and ground station support equipment. The TCD utilized fast scintillators to measure the charge of the primary cosmic ray before any interactions could take place within the calorimeter. The data acquisition electronics handled the output of the various detectors, in a fashion fully integrated with the payload bus. A space-qualified flight computer controlled the acquisition, and was used for preliminary trigger information processing and decision making. Ground support equipment was used to monitor the health of the payload, acquire and archive the data transmitted to the ground, and to provide real-time control of the instrument in flight.

Coutu, Stephane

2005-01-01

150

Cosmic ray diffusion: Report of the Workshop in Cosmic Ray Diffusion Theory  

NASA Technical Reports Server (NTRS)

A workshop in cosmic ray diffusion theory was held at Goddard Space Flight Center on May 16-17, 1974. Topics discussed and summarized are: (1) cosmic ray measurements as related to diffusion theory; (2) quasi-linear theory, nonlinear theory, and computer simulation of cosmic ray pitch-angle diffusion; and (3) magnetic field fluctuation measurements as related to diffusion theory.

Birmingham, T. J.; Jones, F. C.

1975-01-01

151

Cosmic X-ray physics  

NASA Technical Reports Server (NTRS)

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1985-01-01

152

Strangelets accelerated by pulsars in galactic cosmic rays  

E-print Network

It is shown that nuggets of strange quark matter may be extracted from the surface of pulsars and accelerated by strong electric fields to high energies if pulsars are strange stars with the crusts, comprised of nuggets embedded in a uniform electron background. Such high energy nuggets called usually strangelets give an observable contribution into galactic cosmic rays and may be detected by the upcoming cosmic ray experiment Alpha Magnetic Spectrometer AMS-02 on the International Space Station.

K. S. Cheng; V. V. Usov

2006-11-20

153

Detection of reflected Cherenkov light from extensive air showers in the SPHERE experiment as a method of studying superhigh energy cosmic rays  

NASA Astrophysics Data System (ADS)

Although a large number of experiments were carried out during the last few decades, the uncertainty in the spectrum of all nuclei of primary cosmic rays (PCRs) with superhigh energies is still high, and the results of many experiments on nuclear composition of PCRs are contradictory. An overview of the SPHERE experiment on detecting Vavilov-Cherenkov radiation from extensive air shower (EAS) reflected from a ground snow surface is given. A number of experimental studies implementing this method are presented and their results are analyzed. Some other popular methods of studying PCRs with superhigh energies ( E 0 > 1015 eV) and their main advantages and drawbacks are briefly considered. The detecting equipment of the SPHERE-2 experiment and the technique of its calibration are considered. The optical properties of snow, which are important for experiments on reflected Cherenkov light (CL) from EAS, are discussed and the history of observing reflected EAS CL is described. The algorithm of simulating the detector response and calculating the fiducial acceptance of shower detection is described. The procedure of processing the experimental data with a subsequent reconstruction of the spectrum of all PCR nuclei and analysis of the mass composition is shown. The first results of reconstructing the spectrum and separating groups of cosmic-ray nuclei with high energies in the SPHERE-2 experiment are presented. Main sources of systematic errors are considered. The prospects of developing the technique of observation of reflected EAS CL in future experiments are discussed.

Antonov, R. A.; Aulova, T. V.; Bonvech, E. A.; Galkin, V. I.; Dzhatdoev, T. A.; Podgrudkov, D. A.; Roganova, T. M.; Chernov, D. V.

2015-01-01

154

Cosmic Ray Physics with ACORDE at LHC  

E-print Network

The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10^15 - 10^17 eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.

C. Pagliarone; A. Fernandez-Tellez

2007-09-19

155

Cosmic rays and space weather  

NASA Astrophysics Data System (ADS)

It is well known that in periods of great FEP (Flare Energetic Particle), fluxes can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead (each year insurance companies paid more than 500,000,000 dollars for these failures). In these periods is necessary to switch off some part of electronics for short time to protect computer memories. These periods are also dangerous for astronauts on space-ships, and passengers and crew in commercial jets (especially during S5 radiation storms according to classification of NOAA). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (about 5-10 GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coefficient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into solar wind) than main part of smaller energy particles caused dangerous situation for electronics and people health (about 30-60 minutes later). We describe here principles and experience of automatically working programs "FEP-Search-1 min", "FEP-Search-2 min","FEP-Search-5 min", developed and checked in the Emilio Segre' Observatory of Israel Cosmic Ray Center (2025 m above sea level, cut-off rigidity 10.8 GV). The second step is automatically determination of flare energetic particle spectrum, and then automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere and on the ground. We will describe also the theory and experience of high energy cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects (what influenced very much on communications, working of navigation systems, satellites and high-level technology systems in space and, the atmosphere, and on the ground). The review and original part will contain following parts: 1. Introduction (cosmic rays as object and instrument of space weather monitoring and forecasting). 2. On-line search of the start of great Flare Energetic Particle (FEP) events, automatically formation of Alerts, estimation of probability of false alerts and probability of missing alerts (realized in Israel Cosmic Ray Center and Emilio Segre’ Observatory). 3. On-line determination of flare energetic particle spectrum by the method of coupling functions. 4. Automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere, and on the ground in dependence of cut-off rigidity. 5. Cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects.

Dorman, L. I.

2003-04-01

156

Cosmic Rays on the Pacific Ocean  

Microsoft Academic Search

Records of cosmic-ray intensity obtained on the R. M. S. Aorangi during 12 voyages between Vancouver, Canada and Sydney, Australia, from March 17, 1936, to January 18, 1937, using a Carnegie model C cosmic-ray meter, are described and discussed. Typical records exhibiting the latitude effect are shown. A summary of the data taken at sea is given in the form

A. H. Compton; R. N. Turner

1937-01-01

157

The Discovery and Nature of Cosmic Rays  

NSDL National Science Digital Library

In this lesson, students will learn how cosmic rays were discovered and what they are - including their size and speed. Includes background information for the teacher, questions, activities and information about student preconceptions. This is lesson 1 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

2012-08-03

158

Early history of cosmic rays at Chicago  

NASA Astrophysics Data System (ADS)

Cosmic ray studies at the University of Chicago were started by Arthur Compton during the late 1920s. The high points of cosmic ray studies at Chicago under Compton and Marcel Schein are the focus of this report, which summarizes the research done at Chicago up to the end of World War II.

Yodh, Gaurang B.

2013-02-01

159

Influence of Cosmic Rays on Earth's Climate  

Microsoft Academic Search

During the last solar cycle Earth's cloud cover underwent a modulation more closely in phase with the galactic cosmic ray flux than with other solar activity parameters. Further it is found that Earth's temperature follows more closely decade variations in galactic cosmic ray flux and solar cycle length, than other solar activity parameters. The main conclusion is that the average

Henrik Svensmark

1998-01-01

160

Low Cloud Properties Influenced by Cosmic Rays  

Microsoft Academic Search

The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds \\\\(<=3 km\\\\), which points to a microphysical mechanism involving aerosol formation that is enhanced by ionization due to cosmic rays.

Nigel D. Marsh; Henrik Svensmark

2000-01-01

161

Satellite Anomalies from Galactic Cosmic Rays  

Microsoft Academic Search

Anomalies in communication satellite operation have been caused by the unexpected triggering of digital circuits. Interactions with galactic cosmic rays were investigated as a mechanism for a number of these events. The mechanism assumed was the charging of the base-emitter capacitance of sensitive transistors to the turn-on voltage. The calculation of the cosmic ray event rate required the determination of

D. Binder; E. C. Smith; A. B. Holman

1975-01-01

162

Research in cosmic and gamma ray astrophysics  

NASA Technical Reports Server (NTRS)

Research activities in cosmic rays, gamma rays, and astrophysical plasmas are covered. The activities are divided into sections and described, followed by a bibliography. The astrophysical aspects of cosmic rays, gamma rays, and of the radiation and electromagnetic field environment of the Earth and other planets are investigated. These investigations are performed by means of energetic particle and photon detector systems flown on spacecraft and balloons.

Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

1989-01-01

163

Gamma-Ray Astronomy of Cosmic Rays  

E-print Network

Many of the basic problems in the astrophysics of charged Cosmic Rays remain on principle unresolved by in situ observations in the Solar System due to the chaotic nature of the propagation of these particles in Interstellar space. This concerns the existence and the nature of localized individual particle sources as well as the transport in the Galaxy and establishes the need for astronomical observations of secondary gamma-rays. The only exception may be the highest energy particles at energies around $10^{20}$ eV which possibly reach us on straight line orbits from their production sites. Recently such gamma-ray observations, both in space and on the ground, have made great progress even though the instrumental sensitivities are still low. It is argued that two basic questions, regarding first of all the Supernova Remnant source hypothesis and secondly the contributions to the diffuse gamma-ray background, have come close to an empirical resolution. Apart from motivations deriving from extragalactic astronomy this expectation is at the root of the construction of a new generation of high-sensitivity gamma-ray instruments. As a representative example the H.E.S.S. array of atmospheric Cherenkov telescopes is described.

Heinrich Voelk

2002-02-22

164

30TH INTERNATIONAL COSMIC RAY CONFERENCE A Search for Prompt Very High Energy Emission from Satellite-detected Gamma-  

E-print Network

would allow us to constrain GRB models. Since its launch, in late 2004, the Swift satellite has been Satellite-detected Gamma- ray Bursts using Milagro P. M. SAZ PARKINSON & B. L. DINGUS ¡ FOR THE MILAGRO, including 57 since the launch of Swift (through May 2007). We discuss the results of the searches for prompt

California at Santa Cruz, University of

165

High energy physics in cosmic rays  

SciTech Connect

In the first half-century of cosmic ray physics, the primary research focus was on elementary particles; the positron, pi-mesons, mu-mesons, and hyperons were discovered in cosmic rays. Much of this research was carried out at mountain elevations; Pic du Midi in the Pyrenees, Mt. Chacaltaya in Bolivia, and Mt. Evans/Echo Lake in Colorado, among other sites. In the 1960s, claims of the observation of free quarks, and satellite measurements of a significant rise in p-p cross sections, plus the delay in initiating accelerator construction programs for energies above 100 GeV, motivated the Michigan-Wisconsin group to undertake a serious cosmic ray program at Echo Lake. Subsequently, with the succession of higher energy accelerators and colliders at CERN and Fermilab, cosmic ray research has increasingly focused on cosmology and astrophysics, although some groups continue to study cosmic ray particle interactions in emulsion chambers.

Jones, Lawrence W. [University of Michigan, Ann Arbor, Michigan (United States)

2013-02-07

166

Cosmic Ray Background Analysis for MuLAN  

NASA Astrophysics Data System (ADS)

The goal of the MuLAN experiment is to make a measurement of the muon lifetime to a precision of 1 ppm so that a 5 ppm value of the Fermi coupling constant can be calculated. To do this, a beam of positive muons is stopped in a target surrounded by 340 scintillating detectors arranged in a geodesic around the target. Once the muons stop in the target, they decay, and the product positrons are emitted outward, where they are detected by the scintillators. By examining the spectrum of decay times, the lifetime of positive muons can be calculated. One of the myriad factors affecting this measurement is the background of cosmic ray muons constantly showering upon the detector. To study this background, an angular distribution of the cosmic rays was found, and the rate at which cosmic rays muons ``rain'' upon the detector was calculated. In addition, the cosmic rays were used to examine the timing differences between the individual scintillators.

Mangialardi, Michael

2008-10-01

167

Cosmic-Ray Modulation Equations  

NASA Astrophysics Data System (ADS)

The temporal variation of the cosmic-ray intensity in the heliosphere is called cosmic-ray modulation. The main periodicity is the response to the 11-year solar activity cycle. Other variations include a 27-day solar rotation variation, a diurnal variation, and irregular variations such as Forbush decreases. General awareness of the importance of this cosmic-ray modulation has greatly increased in the last two decades, mainly in communities studying cosmogenic nuclides, upper atmospheric physics and climate, helio-climatology, and space weather, where corrections need to be made for these modulation effects. Parameterized descriptions of the modulation are even used in archeology and in planning the flight paths of commercial passenger jets. The qualitative, physical part of the modulation is generally well-understood in these communities. The mathematical formalism that is most often used to quantify it is the so-called Force-Field approach, but the origins of this approach are somewhat obscure and it is not always used correct. This is mainly because the theory was developed over more than 40 years, and all its aspects are not collated in a single document. This paper contains a formal mathematical description intended for these wider communities. It consists of four parts: (1) a description of the relations between four indicators of "energy", namely energy, speed, momentum and rigidity, (2) the various ways of how to count particles, (3) the description of particle motion with transport equations, and (4) the solution of such equations, and what these solutions mean. Part (4) was previously described in Caballero-Lopez and Moraal (J. Geophys. Res, 109: A05105, doi: 10.1029/2003JA010358, 2004). Therefore, the details are not all repeated here. The style of this paper is not to be rigorous. It rather tries to capture the relevant tools to do modulation studies, to show how seemingly unrelated results are, in fact, related to one another, and to point out the historical context of some of the results. The paper adds no new knowledge. The summary contains advice on how to use the theory most effectively.

Moraal, H.

2013-06-01

168

High-Energy Cosmic Rays and Neutrinos from Gamma-Ray Bursts  

E-print Network

A complete model for the origin of high-energy >~10^{14} eV) cosmic rays from gamma-ray bursts (GRBs) and implications of this hypothesis are described. Detection of high-energy neutrinos from GRBs provide an unambiguous test of the model. Evidence for cosmic-ray acceleration in GRBs is suggested by the detection of anomalous gamma-ray components such as that observed from GRB 941017. Neutron beta-decay halos around star-forming galaxies such as the Milky Way are formed as a consequence of this model. Cosmic rays from GRBs in the Galaxy are unlikely to account for the ~10^{18} eV cosmic-ray excess reported by the Sydney University Giant Air Shower Recorder (SUGAR), but could contribute to past extinction events.

C. Dermer

2005-06-16

169

Shielding against galactic cosmic rays  

NASA Technical Reports Server (NTRS)

Ions of galactic origin are modified but not attenuated by the presence of shielding materials. Indeed, the number of particles and the absorbed energy behind most shield materials increases as a function of shield thickness. The modification of the galactic cosmic ray composition upon interaction with shielding is the only effective means of providing astronaut protection. This modification is intimately conntected with the shield transport porperties and is a strong function of shield composition. The systematic behavior of the shield properites in terms of microscopic energy absorption events will be discussed. The shield effectiveness is examined with respect to convectional protection practice and in terms of a biological endpoint: the efficiency for reduction of the probability of transformation of shielded C3H1OT1/2 mouse cells. The relative advantage of developing new shielding technologies is discussed in terms of a shield performance as related to biological effect and the resulting uncertainty in estimating astronaut risk.

Schimmerling, W.; Wilson, J. W.; Nealy, J. E.; Thibeault, S. A.; Cucinotta, F. A.; Shinn, J. L.; Kim, M.; Kiefer, R.

1996-01-01

170

Gamma-ray astronomy and the origin of cosmic rays  

NASA Technical Reports Server (NTRS)

Recent observations of cosmic gamma radiation are reviewed. It is shown that this radiation consists of an extragalactic background as well as a bright band of galactic radiation lying in the plane of the Milky Way and produced primarily by cosmic-ray collisions with interstellar gas atoms. The galactic gamma radiation is divided into a near component apparently associated with Gould's belt and a far component originating about 15,000 light years away and narrowly confined to the galactic plane. A Great Galactic Ring is identified which is 35,000 light years in diameter and in which most galactic cosmic rays are produced and supernovae and pulsars are concentrated. The physical mechanisms responsible for the production of most of the cosmic gamma rays in the Galaxy are examined, and the origin of galactic cosmic rays is considered. It is concluded that the cosmic rays are produced either in supernova explosions or in the pulsars they leave behind

Stecker, F. W.

1978-01-01

171

Cosmic Rays from Gamma Ray Bursts in the Galaxy  

E-print Network

The rate of terrestrial irradiation events by galactic gamma-ray bursts (GRBs) is estimated using recent standard-energy results. We assume that GRBs accelerate high-energy cosmic rays, and present results of three-dimensional simulations of cosmic rays moving in the Galactic magnetic field and diffusing through pitch-angle scattering. An on-axis GRB extinction event begins with a powerful prompt gamma-ray and neutron pulse, followed by a longer-lived phase from cosmic-ray protons and neutron-decay protons that diffuse towards Earth. Our results force a reinterpretation of reported ~ 10^{18} eV cosmic-ray anisotropies and offer a rigorous test of the model where high-energy cosmic rays originate from GRBs, which will soon be tested with the Auger Observatory.

Charles D. Dermer; Jeremy M. Holmes

2005-06-16

172

Sulphur mountain: Cosmic ray intensity records  

SciTech Connect

This book deals with the comic ray intensity registrations at the Sulphur Mountain Cosmic Ray Laboratory. The time series of intensity form a valuable data-set, for studying cosmic ray intensity variations and their dependence on solar activity. The IGY neutron monitor started operating from July 1, 1957 and continued through 1963. Daily mean values are tabulated for the period and these are also represented in plots. This monitor was set up by the National Research Council of Canada.

Venkatesan, D.; Mathews, T.

1985-01-01

173

Cosmic-Ray Propagation in Molecular Clouds  

NASA Astrophysics Data System (ADS)

Cosmic rays constitute the main ionising and heating agent in dense, starless, molecular cloud cores. We reexamine the physical quantities necessary to determine the cosmic-ray ionisation rate (especially the cosmic-ray spectrum at E < 1 GeV and the ionisation cross sections), and calculate the ionisation rate as a function of the column density of molecular hydrogen. Available data support the existence of a low-energy component (below ˜ 100 MeV) of cosmic-ray electrons or protons responsible for the ionisation of diffuse and dense clouds. We also compute the attenuation of the cosmic-ray flux rate in a cloud core taking into account magnetic focusing and magnetic mirroring, following the propagation of cosmic rays along flux tubes enclosing different amount of mass and mass-to-flux ratios. We find that mirroring always dominates over focusing, implying a reduction of the cosmic-ray ionisation rate by a factor of 3 to 4 depending on the position inside the core and the magnetisation of the core.

Padovani, Marco; Galli, Daniele

174

Cosmogenic gamma rays and the composition of cosmic rays  

SciTech Connect

We discuss the prospects of detecting the sources of ultrahigh energy (UHE) cosmic ray (CR) nuclei via their emission of cosmogenic {gamma} rays in the GeV to TeV energy range. These {gamma} rays result from electromagnetic cascades initiated by high energy photons, electrons, and positrons that are emitted by CRs during their propagation in the cosmic radiation background and are independent of the simultaneous emission of {gamma} rays in the vicinity of the source. The corresponding production power by UHE CR nuclei (with mass number A and charge Z) is dominated by pion photo production ({proportional_to}A) and Bethe-Heitler pair production ({proportional_to}Z{sup 2}). We show that the cosmogenic {gamma}-ray signal from a single steady UHE CR source is typically more robust with respect to variations of the source composition and injection spectrum than the accompanying signal of cosmogenic neutrinos. We study the diffuse emission from the sum of extragalactic CR sources as well as the point-source emission of the closest sources.

Ahlers, Markus [C. N. Yang Institute for Theoretical Physics, SUNY at Stony Brook, Stony Brook, New York 11794-3840 (United States); Salvado, Jordi [Departament d'Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, 647 Diagonal, E-08028 Barcelona (Spain)

2011-10-15

175

The Lateral Trigger Probability function for the Ultra-High Energy Cosmic Ray Showers detected by the Pierre Auger Observatory  

E-print Network

In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an extensive air shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 10^{17} and 10^{19} eV and zenith angles up to 65 degs. A parametrization combining a step function with an exponential is found to reproduce them very well in the considered range of energies and zenith angles. The LTP functions can also be obtained from data using events simultaneously observed by the fluorescence and the surface detector of the Pierre Auger Observatory (hybrid events). We validate the Monte-Carlo results sho...

Abreu, P; Ahn, E J; Albuquerque, I F M; Allard, D; Allekotte, I; Allen, J; Allison, P; Castillo, J Alvarez; Alvarez-Muñiz, J; Ambrosio, M; Aminaei, A; Anchordoqui, L; Andringa, S; Anti?i?, T; Anzalone, A; Aramo, C; Arganda, E; Arqueros, F; Asorey, H; Assis, P; Aublin, J; Ave, M; Avenier, M; Avila, G; Bäcker, T; Balzer, M; Barber, K B; Barbosa, A F; Bardenet, R; Barroso, S L C; Baughman, B; Bäuml, J; Beatty, J J; Becker, B R; Becker, K H; Bellétoile, A; Bellido, J A; BenZvi, S; Berat, C; Bertou, X; Biermann, P L; Billoir, P; Blanco, F; Blanco, M; Bleve, C; Blümer, H; Bohá?ová, M; Boncioli, D; Bonifazi, C; Bonino, R; Borodai, N; Brack, J; Brogueira, P; Brown, W C; Bruijn, R; Buchholz, P; Bueno, A; Burton, R E; Caballero-Mora, K S; Caramete, L; Caruso, R; Castellina, A; Catalano, O; Cataldi, G; Cazon, L; Cester, R; Chauvin, J; Cheng, S H; Chiavassa, A; Chinellato, J A; Chou, A; Chudoba, J; Clay, R W; Coluccia, M R; Conceição, R; Contreras, F; Cook, H; Cooper, M J; Coppens, J; Cordier, A; Coutu, S; Covault, C E; Creusot, A; Criss, A; Cronin, J; Curutiu, A; Dagoret-Campagne, S; Dallier, R; Dasso, S; Daumiller, K; Dawson, B R; de Almeida, R M; De Domenico, M; De Donato, C; de Jong, S J; De La Vega, G; Junior, W J M de Mello; Neto, J R T de Mello; De Mitri, I; de Souza, V; de Vries, K D; Decerprit, G; del Peral, L; del Río, M; Deligny, O; Dembinski, H; Dhital, N; Di Giulio, C; Diaz, J C; Castro, M L Díaz; Diep, P N; Dobrigkeit, C; Docters, W; D'Olivo, J C; Dong, P N; Dorofeev, A; Anjos, J C dos; Dova, M T; D'Urso, D; Dutan, I; Ebr, J; Engel, R; Erdmann, M; Escobar, C O; Espadanal, J; Etchegoyen, A; Luis, P Facal San; Tapia, I Fajardo; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Ferguson, A P; Ferrero, A; Fick, B; Filevich, A; Filip?i?, A; Fliescher, S; Fracchiolla, C E; Fraenkel, E D; Fröhlich, U; Fuchs, B; Gaior, R; Gamarra, R F; Gambetta, S; García, B; Gámez, D García; Garcia-Pinto, D; Gascon, A; Gemmeke, H; Gesterling, K; Ghia, P L; Giaccari, U; Giller, M; Glass, H; Gold, M S; Golup, G; Albarracin, F Gomez; Berisso, M Gómez; Gonçalves, P; Gonzalez, D; Gonzalez, J G; Gookin, B; Góra, D; Gorgi, A; Gouffon, P; Gozzini, S R; Grashorn, E; Grebe, S; Griffith, N; Grigat, M; Grillo, A F; Guardincerri, Y; Guarino, F; Guedes, G P; Guzman, A; Hague, J D; Hansen, P; Harari, D; Harmsma, S; Harton, J L; Haungs, A; Hebbeker, T; Heck, D; Herve, A E; Hojvat, C; Hollon, N; Holmes, V C; Homola, P; Hörandel, J R; Horneffer, A; Hrabovský, M; Huege, T; Insolia, A; Ionita, F; Italiano, A; Jarne, C; Jiraskova, S; Josebachuili, M; Kadija, K; Kampert, K H; Karhan, P; Kasper, P; Kégl, B; Keilhauer, B; Keivani, A; Kelley, J L; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Knapp, J; Koang, D -H; Kotera, K; Krohm, N; Krömer, O; Kruppke-Hansen, D; Kuehn, F; Kuempel, D; Kulbartz, J K; Kunka, N; La Rosa, G; Lachaud, C; Lautridou, P; Leão, M S A B; Lebrun, D; Lebrun, P; de Oliveira, M A Leigui; Lemiere, A; Letessier-Selvon, A; Lhenry-Yvon, I; Link, K; López, R; Agüera, A Lopez; Louedec, K; Bahilo, J Lozano; Lu, L; Lucero, A; Ludwig, M; Lyberis, H; Maccarone, M C; Macolino, C; Maldera, S; Mandat, D; Mantsch, P; Mariazzi, A G; Marin, J; Marin, V; Maris, I C; Falcon, H R Marquez; Marsella, G; Martello, D; Martin, L; Martinez, H; Bravo, O Martínez; Mathes, H J; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mazur, P O; Medina-Tanco, G; Melissas, M; Melo, D; Menichetti, E; Menshikov, A; Mertsch, P; Meurer, C; Mi?anovi?, S; Micheletti, M I; Miller, W; Miramonti, L; Molina-Bueno, L; Mollerach, S; Monasor, M; Ragaigne, D Monnier; Montanet, F; Morales, B; Morello, C; Moreno, E; Moreno, J C; Morris, C; Mostafá, M; Moura, C A; Mueller, S; Muller, M A; Müller, G; Münchmeyer, M; Mussa, R; ‡, G Navarra; Navarro, J L; Navas, S; Necesal, P; Nellen, L; Nelles, A; Neuser, J; Nhung, P T; Niemietz, L; Nierstenhoefer, N; Nitz, D; Nosek, D; Nožka, L; Nyklicek, M; Oehlschläger, J; Olinto, A; Oliva, P; Olmos-Gilbaja, V M; Ortiz, M; Pacheco, N; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Palmieri, N; Parente, G; Parizot, E; Parra, A; Parsons, R D; Pastor, S; Paul, T; Pech, M; P?kala, J; Pelayo, R; Pepe, I M; Perrone, L; Pesce, R; Petermann, E; Petrera, S; Petrinca, P; Petrolini, A; Petrov, Y; Petrovic, J; Pfendner, C; Phan, N; Piegaia, R; Pierog, T; Pieroni, P; Pimenta, M; Pirronello, V; Platino, M; Ponce, V H; Pontz, M; Privitera, P; Prouza, M; Quel, E J; Querchfeld, S; Rautenberg, J; Ravel, O; Ravignani, D; Revenu, B; Ridky, J; Riggi, S; Risse, M; Ristori, P; Rivera, H; Rizi, V; Roberts, J; Robledo, C; de Carvalho, W Rodrigues; Rodriguez, G; Martino, J Rodriguez; Rojo, J Rodriguez; Rodriguez-Cabo, I; Rodríguez-Frías, M D; Ros, G; Rosado, J; Rossler, T; Roth, M; Rouillé-d'Orfeuil, B; Roulet, E; Rovero, A C; Rühle, C; Salamida, F

2011-01-01

176

Galactic cosmic ray flux simulation and prediction.  

PubMed

A dynamic galactic cosmic ray model is proposed to quantitatively describe the z=1-28 ions and electrons of E=10-10(5) MeV/nucleon and their particle flux variations around the Earth's orbit and beyond the Earth's magnetosphere due to diverse large-scale variations of solar activity factors. The variations of large-scale heliospheric magnetic fields and the galactic cosmic ray flux variation time delays relative to solar activity variations are simulated. The lag characteristics and sunspot number predictions having been determined in detail, the model can be used to predict galactic cosmic ray flux levels. PMID:11540366

Nymmik, R A; Panasyuk, M I; Suslov, A A

1996-01-01

177

Cosmic ray propagation in the local superbubble  

NASA Technical Reports Server (NTRS)

It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.

Steitmatter, R. E.; Balasubrahmanyan, V. K.; Protheroe, R. J.; Ormes, J. F.

1984-01-01

178

A theory of Cosmic Rays  

E-print Network

We present a theory of non-solar cosmic rays (CRs) in which the bulk of their observed flux is due to a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes, the position of the `knee(s)' and `ankle', and the CR composition and its variation with energy are all predicted in terms of very simple and completely `standard' physics. The source of CRs is extremely `economical': it has only one parameter to be fitted to the ensemble of all of the mentioned data. All other inputs are `priors', that is, theoretical or observational items of information independent of the properties of the source of CRs, and chosen to lie in their pre-established ranges. The theory is part of a `unified view of high-energy astrophysics' --based on the `Cannonball' model of the relativistic ejecta of accreting black holes and neutron stars. The model has been extremely successful in predicting all the novel properties of Gamma Ray Bursts recently observed with help of the Swift satellite. If correct, this model is only lacking a satisfactory theoretical understanding of the `cannon' that emits the cannonballs in catastrophic processes of accretion.

Arnon Dar; Alvaro De Rujula

2008-05-07

179

The Cosmic Ray Measurements Above 1 TeV  

E-print Network

The Cosmic Ray Measurements Above 1 TeV Shigeru Yoshida Institute for Cosmic Ray Research of cosmic rays with energies above 1 TeV (10 12 eV). Most of the measurements are consistent with our baseline picture of origins of the cosmic rays that the higher energy extragalactic component is starting

Yoshida, Shigeru

180

Cosmic Ray Protons Illuminate Dark Matter Axions  

E-print Network

Cosmic ray protons propagating in a spatially-homogeneous but time-dependent field of axions or axion-like particles (ALPs) emit photons in a way that is reminiscent of Cherenkov radiation by charged particles in a preferred background. We compute the emission rate and energy spectrum of the photons, and discuss the possibility of their detection using the Square Kilometre Array which is currently under construction. In the case of a non-detection, constraints can be placed on the parameter space of ALPs whose mass lie between $10^{-7}$eV and $10^{-5}$ eV under the assumption that they are the primary constituent of dark matter.

H. Tam; Q. Yang

2011-08-16

181

astro-ph/941006720Oct1994 Detection of a Cosmic Ray with Measured Energy Well Beyond the  

E-print Network

background radiation. In the restframe of such an energetic proton, the cosmic microwave radiation Spectral Cuto Due to Cosmic Microwave Radiation D.J. Bird,1;3 S.C. Corbato,2 H.Y. Dai,3 J.W. Elbert,3 K and produce a pion. In the universal restframe (in which the microwave radiation is at rest), the energetic

182

Gamma-rays from cosmic ray interactions in supernova shells  

NASA Technical Reports Server (NTRS)

A model is presented for the transport and interaction of cosmic rays accelerated by a pulsar and confined inside an expanding supernova remnant. Assuming that protons are accelerated at the reverse shock in the confined pulsar wind and convected into the shell via the Rayleigh-Taylor instability, the diffusion and interaction of these protons in the expanding envelope is modeled. The resulting gamma-ray flux is lower than previous estimates due primarily to the inclusion of proton adiabatic losses in the expanding pulsar wind. Energy-dependent diffusion causes the higher energy gamma-ray light curves to decay faster than those at lower energy. The predicted flux from SN1987A, for proton luminosity less than 10 exp 40 erg/s, is below the present detector sensitivities at both GeV and TeV energies, although supernovae occurring within the Galaxy may be detectable.

Harding, A. K.; Mastichiadis, A.; Protheroe, R. J.; Szabo, A. P.

1991-01-01

183

Elemental advances of ultraheavy cosmic rays  

NASA Technical Reports Server (NTRS)

The elemental composition of the cosmic-ray source is different from that which has been generally taken as the composition of the solar system. No general enrichment of products of either r-process or s-process nucleosynthesis accounts for the differences over the entire range of ultraheavy (Z 30) elements; specific determination of nucleosynthetic contributions to the differences depends upon an understanding of the nature of any acceleration fractionation. Comparison between the cosmic-ray source abundances and the abundances of C1 and C2 chondritic meteorites suggests that differences between the cosmic-ray source and the standard (C1) solar system may not be due to acceleration fractionation of the cosmic rays, but rather to a fractionation of the C1 abundances with respect to the interstellar abundances.

1984-01-01

184

Progenitor model of Cosmic Ray knee  

E-print Network

Primary energy spectrum of cosmic rays exhibits a knee at about $3$ PeV where a change in the spectral index occurs. Despite many efforts the origin of such a feature of the spectrum is not satisfactorily solved yet. Here in the framework of hypernova model of galactic cosmic ray origin it is proposed that the steepening of the spectrum beyond the knee may be a consequence of mass distribution of progenitor of cosmic ray source. The proposed model can account all the major observed features about cosmic rays without invoking any fine tuning to match flux or spectra at any energy point. The prediction of the proposed model regarding primary composition scenario beyond the knee is quite different from most of the prevailing models of the knee and thereby can be discriminated from precise experimental measurement of the primary composition.

Bijay, Biplab

2014-01-01

185

Removal of Cosmic Ray-Induced Noise from Kepler Data  

NASA Astrophysics Data System (ADS)

NASA's Kepler Mission is designed to detect transiting exoplanets by measuring stellar brightness attenuation as small as 84 parts per million. Attaining the required photometric precision depends partly on the ability of ground-based data processing algorithms to mitigate the effects of significant noise sources. Among these is the charge released in the photometer's CCDs by cosmic rays and solar energetic particles (we loosely refer to all such particles as "cosmic rays", regardless of their origin), which continuously bombard the instrument with an estimated mean flux of of 5 cm-2 s-1. Cosmic ray strikes appear in pixel time series as a sequence of positive impulses affecting roughly one in five long cadence measurements (Kepler's primary data collection mode). The problem of separating cosmic ray-induced signal from other signal components is complicated both by the 30 min effective integration period of a long cadence measurement and by the fact that high-frequency stellar variations and image motion can also produce impulse-like features in pixel flux time series. We present an algorithm for detecting and removing the effects of cosmic rays on Kepler pixel time series. Given the pixels comprising a target star's aperture, each variance-normalized and lightly detrended time series is modeled as a combination of the effects of intrinsic stellar variability, image motion, and cosmic ray strikes. The cosmic ray signal component is modeled as a Poisson process in which the magnitude of each event is drawn from a known distribution, while stellar variability is modeled as the sum of an autoregressive process and a small set (possibly empty) of salient harmonic components. Both simulation tests and analysis of results from Kepler flight data demonstrate the algorithm's effectiveness. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science Mission Directorate.

Morris, Robert L.; Jenkins, J. M.; Twicken, J.

2012-10-01

186

Calibration of a solid state nuclear track detector (SSNTD) with high detection threshold to search for rare events in cosmic rays  

NASA Astrophysics Data System (ADS)

We have investigated a commercially available polymer for its suitability as a solid state nuclear track detector (SSNTD). We identified that polymer to be polyethylene terephthalate (PET) and found that it has a higher detection threshold compared to many other widely used SSNTDs which makes this detector particularly suitable for rare event search in cosmic rays as it eliminates the dominant low Z background. Systematic studies were carried out to determine its charge response which is essential before any new material can be used as an SSNTD. In this paper we describe the charge response of PET to 129Xe, 78Kr and 49Ti ions from the REX-ISOLDE facility at CERN, present the calibration curve for PET and characterize it as a nuclear track detector.

Dey, S.; Gupta, D.; Maulik, A.; Raha, Sibaji; Saha, Swapan K.; Syam, D.; Pakarinen, J.; Voulot, D.; Wenander, F.

2011-06-01

187

Calibration of a solid state nuclear track detector (SSNTD) with high detection threshold to search for rare events in cosmic rays  

E-print Network

We have investigated a commercially available polymer for its suitability as a solid state nuclear track detector (SSNTD). We identified that polymer to be polyethylene terephthalate (PET) and found that it has a higher detection threshold compared to many other widely used SSNTDs which makes this detector particularly suitable for rare event search in cosmic rays as it eliminates the dominant low Z background. Systematic studies were carried out to determine its charge response which is essential before any new material can be used as an SSNTD. In this paper we describe the charge response of PET to 129Xe, 78Kr and 49Ti ions from the REX-ISOLDE facility at CERN, present the calibration curve for PET and characterize it as a nuclear track detector.

S. Dey; D. Gupta; A. Maulik; Sibaji Raha; Swapan K. Saha; D. Syam; J. Pakarinen; D. Voulot; F. Wenander

2011-03-23

188

Large Scale Distribution of Ultra High Energy Cosmic Rays Detected at the Pierre Auger Observatory with Zenith Angles up to 80°  

NASA Astrophysics Data System (ADS)

We present the results of an analysis of the large angular scale distribution of the arrival directions of cosmic rays with energy above 4 EeV detected at the Pierre Auger Observatory including for the first time events with zenith angle between 60° and 80°. We perform two Rayleigh analyses, one in the right ascension and one in the azimuth angle distributions, that are sensitive to modulations in right ascension and declination, respectively. The largest departure from isotropy appears in the E\\gt 8 EeV energy bin, with an amplitude for the first harmonic in right ascension r1? =(4.4+/- 1.0)× {{10}-2}, that has a chance probability P(?slant r1? )=6.4× {{10}-5}, reinforcing the hint previously reported with vertical events alone.

Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Aranda, V. M.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Awal, N.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blaess, S. G.; Blanco, M.; Bleve, C.; Blümer, H.; Bohá?ová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Bridgeman, A.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Cordier, A.; Coutu, S.; Covault, C. E.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D’Olivo, J. C.; Dorofeev, A.; Dorosti Hasankiadeh, Q.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filip?i?, A.; Fox, B. D.; Fratu, O.; Freire, M. M.; Fröhlich, U.; Fuchs, B.; Fujii, T.; Gaior, R.; García, B.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Malacari, M.; Maldera, S.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mari?, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Melissas, M.; Melo, D.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mi?anovi?, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Müller, S.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Oliveira, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; P?kala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.

2015-04-01

189

28th International Cosmic Ray Conference 3851 A 2D stochastic simulation of galactic cosmic rays transport  

E-print Network

28th International Cosmic Ray Conference 3851 A 2D stochastic simulation of galactic cosmic rays, Russia. Abstract We present a new code to numerically simulate the transport of galactic cosmic rays Galactic cosmic rays suffer from modulation in the heliosphere. Basic modulation mechanisms are diffusion

Usoskin, Ilya G.

190

Apollo 17 lunar surface cosmic ray detector  

NASA Technical Reports Server (NTRS)

The objectives and selected data are presented for the Apollo 17 Lunar Surface Cosmic Ray Experiment (LSCRE) for the purpose of introducing an analysis of three of the separate detectors contained within in LSCRE package. The mica detector for measuring heavy solar wind, and the lexan stack and glass detectors for measuring energetic particles in space are discussed in terms of their deployment, exposure time, calibration, and data yield. Relevant articles on solar particles, interplanetary ions, and cosmic ray nuclei are also included.

Walker, R. M.

1974-01-01

191

Recent developments in cosmic ray physics  

NASA Astrophysics Data System (ADS)

The search for a theory of the origin of cosmic rays that may be considered as a standard, agreeable model is still ongoing. On one hand, much circumstantial evidence exists of the fact that supernovae in our Galaxy play a crucial role in producing the bulk of cosmic rays observed on Earth. On the other hand, important questions about their ability to accelerate particles up to the knee remain unanswered. The common interpretation of the knee as a feature coinciding with the maximum energy of the light component of cosmic rays and a transition to a gradually heavier mass composition is mainly based on KASCADE results. Some recent data appear to question this finding: YAC1 - Tibet Array and ARGO-YBJ find a flux reduction in the light component at ? 700 TeV, appreciably below the knee. Whether the maximum energy of light nuclei is as high as 3000 TeV or rather as low as a few hundred TeV has very important consequences on the supernova remnant paradigm for the origin of cosmic rays, as well on the crucial issue of the transition from Galactic to extragalactic cosmic rays. In such a complex phenomenological situation, it is important to have a clear picture of what is really known and what is not. Here I will discuss some solid and less solid aspects of the theory (or theories) for the origin of cosmic rays and the implications for future searches in this field.

Blasi, P.

2014-11-01

192

Multi-spectra Cosmic Ray Flux Measurement  

NASA Astrophysics Data System (ADS)

The Earth's upper atmosphere is constantly bombarded by rain of charged particles known as primary cosmic rays. These primary cosmic rays will collide with the atmospheric molecules and create extensive secondary particles which shower downward to the surface of the Earth. In recent years, a few studies have been done regarding to the applications of the cosmic ray measurements and the correlations between the Earth's climate conditions and the cosmic ray fluxes [1,2,3]. Most of the particles, which reach to the surface of the Earth, are muons together with a small percentage of electrons, gammas, neutrons, etc. At Georgia State University, multiple cosmic ray particle detectors have been constructed to measure the fluxes and energy distributions of the secondary cosmic ray particles. In this presentation, we will briefly describe these prototype detectors and show the preliminary test results. Reference: [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, Nature, Vol.422, 277 (2003). [2] L.V. Egorova, V. Ya Vovk, O.A. Troshichev, Journal of Atmospheric and Terrestrial Physics 62, 955-966 (2000). [3] Henrik Svensmark, Phy. Rev. Lett. 81, 5027 (1998). )

He, Xiaochun; Dayananda, Mathes

2010-02-01

193

Cosmic ray produced isotopes in terrestrial systems.  

NASA Astrophysics Data System (ADS)

Continuing improvements in the sensitivity of measurement of cosmic ray produced isotopes in environmental samples have progressively broadened the scope of their applications to characterise and quantify a wide variety of processes in Earth and planetary sciences. In this article, the author concentrates on the new developments in the field of nuclear geophysics, based on isotopic changes produced by cosmic rays in the terrestrial systems. This field, which is best described as cosmic ray geophysics, has roots with the discovery of cosmogenic 14C on the Earth by Willard Libby in 1948, and grew rapidly at first, but slowed down during the '60s and '70s. In the '80s, there was a renaissance in cosmic ray produced isotope studies, thanks mainly to the developments of the accelerator mass spectrometry technique capable of measuring minute amounts of radioactivity in terrestrial samples. This technological advance has considerably enhanced the applications of cosmic ray produced isotopes and today one finds them being used to address diverse problems in Earth and planetary sciences. The author discusses the present scope of the field of cosmic ray geophysics with an emphasis on geomorphology. It is stressed that this is the decade in which this field, which has been studied passionately by geographers, geomorphologists and geochemists for more than five decades, has at its service nuclear methods to introduce numeric time controls in the range of centuries to millions of years.

Lal, D.

1998-12-01

194

COSMIC-RAY HELIUM HARDENING  

SciTech Connect

Recent observations by the CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic-ray (CR) helium is harder than that of CR protons below the knee energy, 10{sup 15}eV, and (2) all CR spectra become hard at {approx}>10{sup 11}eV nucleon{sup -1}. We propose a new idea, that higher energy CRs are generated in a more helium-rich region, to explain the hardening without introducing different sources for CR helium. The helium-to-proton ratio at {approx}100 TeV exceeds the Big Bang abundance Y = 0.25 by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in a chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium if CRs escape from the supernova remnant shock in an energy-dependent way. We provide a simple analytical spectrum that also fits well the hardening due to the decreasing Mach number in the hot superbubble with {approx}10{sup 6} K. Our model predicts hard and concave spectra for heavier CR elements.

Ohira, Yutaka; Ioka, Kunihito, E-mail: ohira@post.kek.jp [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan)

2011-03-01

195

Cosmic Rays High Energy Particles  

E-print Network

1937 Anderson, Neddermeyer Muon 1937 Powell Positron ! Antimatter ! 1932 Anderson Pion Cloud chambers ? Charged particles = seeds for condensation cloud chamber / bubble chamber Cosmics Leaving OUtdoor Droplets for condensation cloud chamber / bubble chamber Cosmics Leaving OUtdoor Droplets CERN #12;T.Hebbeker Lightnings

Hebbeker, Thomas

196

Contributions to the 19th International Cosmic Ray Conference  

NASA Technical Reports Server (NTRS)

Various aspects of cosmic radiation, its measurements and their patterns are presented. Measurement techniques and variations in solar cosmic ray patterns and calculations of elemental abundances are reviewed.

1985-01-01

197

Spiral arms as cosmic ray source distributions  

NASA Astrophysics Data System (ADS)

The Milky Way is a spiral galaxy with (or without) a bar-like central structure. There is evidence that the distribution of suspected cosmic ray sources, such as supernova remnants, are associated with the spiral arm structure of galaxies. It is yet not clearly understood what effect such a cosmic ray source distribution has on the particle transport in our Galaxy. We investigate and measure how the propagation of Galactic cosmic rays is affected by a cosmic ray source distribution associated with spiral arm structures. We use the PICARD code to perform high-resolution 3D simulations of electrons and protons in galactic propagation scenarios that include four-arm and two-arm logarithmic spiral cosmic ray source distributions with and without a central bar structure as well as the spiral arm configuration of the NE2001 model for the distribution of free electrons in the Milky Way. Results of these simulation are compared to an axisymmetric radial source distribution. Also, effects on the cosmic ray flux and spectra due to different positions of the Earth relative to the spiral structure are studied. We find that high energy electrons are strongly confined to their sources and the obtained spectra largely depend on the Earth's position relative to the spiral arms. Similar finding have been obtained for low energy protons and electrons albeit at smaller magnitude. We find that even fractional contributions of a spiral arm component to the total cosmic ray source distribution influences the spectra on the Earth. This is apparent when compared to an axisymmetric radial source distribution as well as with respect to the Earth's position relative to the spiral arm structure. We demonstrate that the presence of a Galactic bar manifests itself as an overall excess of low energy electrons at the Earth. Using a spiral arm geometry as a cosmic ray source distributions offers a genuine new quality of modeling and is used to explain features in cosmic ray spectra at the Earth that are else-wise attributed to other propagation effects. We show that realistic cosmic ray propagation scenarios have to acknowledge non-axisymmetric source distributions.

Werner, M.; Kissmann, R.; Strong, A. W.; Reimer, O.

2015-04-01

198

HIGH-ENERGY X-RAY DETECTION OF G359.89–0.08 (SGR A–E): MAGNETIC FLUX TUBE EMISSION POWERED BY COSMIC RAYS?  

E-print Network

We report the first detection of high-energy X-ray (E > 10 keV) emission from the Galactic center non-thermal filament G359.89–0.08 (Sgr A–E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The ...

Zhang, Shuo

199

The galactic cosmic ray ionization rate  

PubMed Central

The chemistry that occurs in the interstellar medium in response to cosmic ray ionization is summarized, and a review of the ionization rates that have been derived from measurements of molecular abundances is presented. The successful detection of large abundances of H3+ in diffuse clouds and the recognition that dissociative recombination of H3+ is fast has led to an upward revision of the derived ionization rates. In dense clouds the molecular abundances are sensitive to the depletion of carbon monoxide, atomic oxygen, nitrogen, water, and metals and the presence of large molecules and grains. Measurements of the relative abundances of deuterated species provide information about the ion removal mechanisms, but uncertainties remain. The models, both of dense and diffuse clouds, that are used to interpret the observations may be seriously inadequate. Nevertheless, it appears that the ionization rates differ in dense and diffuse clouds and in the intercloud medium. PMID:16894166

Dalgarno, A.

2006-01-01

200

Composition of UHE Cosmic Ray Primaries  

E-print Network

Project GRAND presents results on the atomic composition of primary cosmic rays. This is accomplished by determining the average height of primary particles that cause extensive air showers detected by Project GRAND. Particles with a larger cross sectional area, such as iron nuclei, are likely to start an extensive air shower higher in the atmosphere whereas protons, with a smaller cross section, would pass through more air before interacting and thus start showers at lower heights. Such heights can be determined by extrapolating identified muon tracks backward (upward) to determine their height of origin (Gress et al., 1997). Since muons are from the top, hadronic part of the shower, they are a good estimator for the beginning of the shower. The data for this study were taken during the previous year with 20 million shower events.

J. Poirier; J. Carpenter; J. Gress; T. F. Lin; A. Roesch

2000-05-04

201

30TH INTERNATIONAL COSMIC RAY CONFERENCE Numerical Model of Cosmic Ray Induced Ionization in the Atmosphere  

E-print Network

outer space factor affecting the physical- chemical properties of the Earth's atmosphere. In particular, CR are a dominant source of ioniza- tion of the lower/middle atmosphere, producing the cosmic ray to the cosmic ray flux, as measured by ground based neutron monitors (e.g., [1]). However, that is not fully

Usoskin, Ilya G.

202

Detecting ultra-high energy cosmic rays from space with unprecedented acceptance: objectives and design of the JEM-EUSO mission  

NASA Astrophysics Data System (ADS)

The Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO) of the International Space Station (ISS) is the first mission that will study from space Ultra High-Energy Cosmic Rays (UHECR). JEM-EUSO will observe Extensive Air Showers (EAS) produced by UHECRs traversing the Earth's atmosphere from above. For each event, the detector will make accurate measurements of the energy, arrival direction and nature of the primary particle using a target volume far greater than what is achievable from ground. The corresponding increase in statistics will help to clarify the origin and sources of UHECRs as well as the environment traversed during production and propagation. Possibly this will bring new light onto particle physics mechanisms operating at energies well beyond those achievable by man-made accelerators. The spectrum of scientific goals of the JEM-EUSO mission includes as exploratory objectives the detection of high-energy gamma rays and neutrinos, the study of cosmic magnetic fields, and tests of relativity and quantum gravity effects at extreme energies. In parallel JEM-EUSO will systematically perform observation of the surface of the Earth in the infra-red and ultra-violet ranges, studying also atmospheric phenomena (Transient Luminous Effects). The apparatus is a 2 t detector using Fresnel-based optics to focus the UV-light from EAS on a focal surface composed of about 6 000~multianode photomultipliers for a total of ~3 · 105 channels. A multi-layer parallel architecture has been devised to handle the data flow and select valid triggers, reducing it to a rate compatible with downlink constraints. Each processing level filters the event with increasingly complex algorithms using ASICs, FPGAs and DSPs in this order to reject spurious triggers and reduce the data rate.

Casolino, M.; Adams, J. H.; Bertaina, M. E.; Christl, M. J.; Ebisuzaki, T.; Gorodetzky, P.; Hachisu, Y.; Kajino, F.; Kawasaki, Y.; Medina-Tanco, G.; Miyamoto, H.; Ohomori, H.; Parizot, E.; Park, I.; Picozza, P.; Sakaki, N.; Santangelo, A.; Shinozaki, K.; Takizawa, Y.; Tsuno, K.; JEM-EUSO Collaboration

2011-10-01

203

Ultrahigh Energy Cosmic Rays and Prompt TeV Gamma Rays from Gamma Ray Bursts  

E-print Network

Gamma Ray Bursts (GRBs) have been proposed as one {\\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\\gsim10^{20}\\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability of the prompt TeV gamma rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole.

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12

204

Nineteenth International Cosmic Ray Conference. HE Sessions, Volume 8  

NASA Technical Reports Server (NTRS)

Papers submitted for presentation at the 19th International Cosmic Ray Conference are compiled. The present volume contains papers addressing high energy interactions and related phenomena. Specific topic areas include muons, neutrinos, magnetic monopoles, nucleon decay, searches for new particles, and acoustic and thermoluminescence detection techniques.

Jones, F. C. (compiler)

1985-01-01

205

COSMIC RAY BACKGROUND ANALYSIS FOR A CARGO CONTAINER COUNTER.  

SciTech Connect

We have developed a new model for calculating the expected yield of cosmic-ray spallation neutrons in a Cargo Container Counter, and we have benchmarked the model against measurements made with several existing large neutron counters. We also developed two versions of a new measurement uncertainty prediction code based on Microsoft Excel spreadsheets. The codes calculate the minimum detectability limit for the Cargo Container Counter for either neutron singles or doubles counting, and also propagate the uncertainties associated with efficiency normalization flux monitors and cosmic ray flux monitors. This paper will describe the physics basis for this analysis, and the results obtained for several different counter designs.

Ensslin, Norbert; Geist, W. H. (William H.); Lestone, J. P. (John P.); Mayo, D. R. (Douglas R.); Menlove, Howard O.

2001-01-01

206

Analysis of the Arrival Directions of Ultrahigh Energy Cosmic Rays  

E-print Network

The arrival directions of ultrahigh energy extensive air showers (EAS) by Yakutsk, AGASA and SUGAR array data are considered. For the first time, the maps of equal exposition of celestial sphere for the distribution of particles by AGASA and SUGAR array data have been constructed. The large-scale anisotropy of E>4.10^19 eV cosmic rays from the side of Input and Output of the Galaxy Local Arm by Yakutsk, AGASA and SUGAR array data has been detected. The problem of cosmic ray origin is discussed.

A. A. Mikhailov

2007-05-17

207

Observing Ultra-High Energy Cosmic Rays with Smartphones  

E-print Network

We propose a novel approach for observing cosmic rays at ultra-high energy ($>10^{18}$~eV) by repurposing the existing network of smartphones as a ground detector array. Extensive air showers generated by cosmic rays produce muons and high-energy photons, which can be detected by the CMOS sensors of smartphone cameras. The small size and low efficiency of each sensor is compensated by the large number of active phones. We show that if user adoption targets are met, such a network will have significant observing power at the highest energies.

Whiteson, Daniel; Shimmin, Chase; Brodie, Kyle; Burns, Dustin

2014-01-01

208

Observing Ultra-High Energy Cosmic Rays with Smartphones  

E-print Network

We propose a novel approach for observing cosmic rays at ultra-high energy ($>10^{18}$~eV) by repurposing the existing network of smartphones as a ground detector array. Extensive air showers generated by cosmic rays produce muons and high-energy photons, which can be detected by the CMOS sensors of smartphone cameras. The small size and low efficiency of each sensor is compensated by the large number of active phones. We show that if user adoption targets are met, such a network will have significant observing power at the highest energies.

Daniel Whiteson; Michael Mulhearn; Chase Shimmin; Kyle Brodie; Dustin Burns

2014-10-10

209

Cosmic ray sun shadow in Soudan 2 underground muon flux.  

SciTech Connect

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. The authors report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a 3.3{sigma} shadow observed during the years 1995 to 1998.

Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Bode, C.; Fields, T. H.; Goodman, M. C.; Joffe-Minor, T.; Price, L. E.; Seidlein, R.; Soudan 2 Collaboration; Thron, J. L.

1999-06-23

210

Positron fraction in cosmic rays and models of cosmic-ray propagation  

SciTech Connect

The positron fraction observed by PAMELA and other experiments up to {approx}100 GeV is analyzed in terms of models of cosmic-ray propagation. It is shown that generically we expect the positron fraction to reach {approx}0.6 at energies of several TeV, and its energy dependence bears an intimate but subtle connection with that of the boron to carbon ratio in cosmic rays. The observed positron fraction can be fit in a model that assumes a significant fraction of the boron below {approx}10 GeV is generated through spallation of cosmic-ray nuclei in a cocoonlike region surrounding the sources, and the positrons of energy higher than a few GeV are almost exclusively generated through cosmic-ray interactions in the general interstellar medium. Such a model is consistent with the bounds on cosmic-ray anisotropies and other observations.

Cowsik, R.; Burch, B. [Physics Department and McDonnell Center for the Space Sciences, Washington University, St. Louis, Missouri 63130 (United States)

2010-07-15

211

The Interaction of Cosmic Rays with Diffuse Clouds  

NASA Astrophysics Data System (ADS)

We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray-induced heating via Alfvén-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The general analysis method outlined here can apply to diffuse clouds in either the ionized interstellar medium or in galactic winds. We introduce a general-purpose model of cosmic-ray diffusion building upon the hydrodynamic approximation for cosmic rays (from McKenzie & Völk and Breitschwerdt and collaborators). Our improved method self-consistently derives the cosmic-ray flux and diffusivity under the assumption that the streaming instability is the dominant mechanism for setting the cosmic-ray flux and diffusion. We find that, as expected, cosmic rays do not couple to gas within cool clouds (cosmic rays exert no forces inside of cool clouds), that the cosmic-ray density does not increase within clouds (it may decrease slightly in general, and decrease by an order of magnitude in some cases), and that cosmic-ray heating (via Alfvén-wave damping and not collisional effects as for ~10 MeV cosmic rays) is only important under the conditions of relatively strong (10 ?G) magnetic fields or high cosmic-ray pressure (~10-11 erg cm-3).

Everett, John E.; Zweibel, Ellen G.

2011-10-01

212

THE INTERACTION OF COSMIC RAYS WITH DIFFUSE CLOUDS  

SciTech Connect

We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray-induced heating via Alfven-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The general analysis method outlined here can apply to diffuse clouds in either the ionized interstellar medium or in galactic winds. We introduce a general-purpose model of cosmic-ray diffusion building upon the hydrodynamic approximation for cosmic rays (from McKenzie and Voelk and Breitschwerdt and collaborators). Our improved method self-consistently derives the cosmic-ray flux and diffusivity under the assumption that the streaming instability is the dominant mechanism for setting the cosmic-ray flux and diffusion. We find that, as expected, cosmic rays do not couple to gas within cool clouds (cosmic rays exert no forces inside of cool clouds), that the cosmic-ray density does not increase within clouds (it may decrease slightly in general, and decrease by an order of magnitude in some cases), and that cosmic-ray heating (via Alfven-wave damping and not collisional effects as for {approx}10 MeV cosmic rays) is only important under the conditions of relatively strong (10 {mu}G) magnetic fields or high cosmic-ray pressure ({approx}10{sup -11} erg cm{sup -3}).

Everett, John E.; Zweibel, Ellen G., E-mail: everett@physics.wisc.edu [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2011-10-01

213

Radiation Hazard from Galactic Cosmic Rays  

Microsoft Academic Search

Space radiation is a major hazard to astronauts in long-duration human space explosion. Astronauts are exposed to an enormous amount of radiation during their missions away from the Earth in outer space. Deep space is a rich environment of protons, gamma rays and cosmic rays. A healthy 40 years old man staying on Earth away from large doses of radiation

Ashraf Farahat

2006-01-01

214

Lecture notes on high energy cosmic rays  

E-print Network

I give a concise introduction into high energy cosmic ray physics, including also few related aspects of high energy gamma-ray and neutrino astrophysics. The main emphasis is placed on astrophysical questions, and the level of the presentation is kept basic.

M. Kachelriess

2008-01-29

215

Molecular Clouds as Cosmic-Ray Barometers  

E-print Network

It is generally assumed that the flux of cosmic-rays observed at the top of the Earth's atmosphere is representative of the flux in the Galaxy at large. The advent of high sensitivity, high resolution gamma-ray detectors, together with a knowledge of the distribution of the atomic hydrogen and especially of the molecular hydrogen in the Galaxy on sub-degree scales, as provided by the NANTEN survey, creates a unique opportunity to explore the flux of cosmic rays in the Galaxy. We present a methodology which aims to provide a test bed for current and future gamma-ray observatories to explore the cosmic ray flux at various positions in our Galaxy. In particular, for a distribution of molecular clouds and local cosmic ray density as measured at the Earth, we estimate the expected GeV to TeV gamma-ray signal, which can then be compared with observations. An observed gamma-ray flux less than predicted would imply a CR density in specific regions of the Galaxy less than that observed at Earth, and vice versa. The me...

Casanova, S; Fukui, Y; Gabici, S; Jones, D I; Kawamura, A; Onishi, T; Rowell, G; Torii, K; Yamamoto, H

2009-01-01

216

Integral Neutron Multiplicity Measurements from Cosmic Ray Interactions in Lead  

SciTech Connect

Sixty element 3He neutron multiplicity detector systems were designed, constructed and tested for use in cosmic ray experiments with a 30-cm cube lead target. A series of measurements were performed for the cosmic ray configuration at ground level (3 meters water equivalent, mwe), in the St. Petersburg metro tunnel (185 mwe), and in the Pyhasalmi mine in Finland (583 and 1185 mwe). Anomalous coincidence events with charged cosmic ray particles at sea level produced events with 100-120 neutrons due possibly to the total disintegration of the Pb nucleus. These events were also detected at 185 mwe, but the particles causing such disintegration are currently unidentified. We present examples of preliminary data from the various measurements and discuss future plans for underground experiments including possible searches for Weakly Interacting Massive Particles (WIMP, dark matter)

Ward, Thomas E. [Techsource Inc., 1418 Luisa St., Santa Fe. New Mexico 87505 (United States); Rimsky-Korsakov, Alexander A.; Kudryashev, Nikolai A. [V. G. Khlopin Radium Institute, 194021, 2-nd Murinsky pr. 28, St. Petersburg (Russian Federation); Beller, Denis E. [University of Nevada, Las Vegas, 4505 Maryland Parkway Box 454027, Las Vegas, NV 89154-4027 (United States)

2006-07-11

217

Primary cosmic ray particles with z 35 (VVH particles). [very heavy particle detection by high altitude balloons  

NASA Technical Reports Server (NTRS)

Large areas of nuclear emulsions and plastic detectors were exposed to the primary cosmic radiation during high altitude balloon flights. From the analysis of 141 particle tracks recorded during a total exposure of 1.3 x 10 to the 7th power sq m ster.sec., a charge spectrum of the VVH particles has been derived.

Blanford, G. E., Jr.; Friedlander, M. W.; Hoppe, M.; Klarmann, J.; Walker, R. M.; Wefel, J. P.

1972-01-01

218

Cosmic Ray-Air Shower Measurement from Space  

NASA Technical Reports Server (NTRS)

A feasibility study has been initiated to observe from space the highest energy cosmic rays above 1021 eV. A satellite observatory concept, the Maximum-energy Auger (Air)-Shower Satellite (MASS), is recently renamed as the Orbital Wide-angle Collector (OWL) by taking its unique feature of using a very wide field-of-view (FOV) optics. A huge array of imaging devices (about 10(exp 6) pixels) is required to detect and record fluorescent light profiles of cosmic ray cascades in the atmosphere. The FOV of MASS could extend to as large as about 60 in. diameter, which views (500 - 1000 km) of earth's surface and more than 300 - 1000 cosmic ray events per year could be observed above 1020 eV. From far above the atmosphere, the MASS/OWL satellite should be capable of observing events at all angles including near horizontal tracks, and would have considerable aperture for high energy photon and neutrino observation. With a large aperture and the spatial and temporal resolution, MASS could determine the energy spectrum, the mass composition, and arrival anisotropy of cosmic rays from 1020 eV to 1022 eV; a region hitherto not explored by ground-based detectors such as the Fly's Eye and air-shower arrays. MASS/OWL's ability to identify cosmic neutrinos and gamma rays may help providing evidence for the theory which attributes the above cut-off cosmic ray flux to the decay of topological defects. Very wide FOV optics system of MASS/OWL with a large array of imaging devices is applicable to observe other atmospheric phenomena including upper atmospheric lightning. The wide FOV MASS optics being developed can also improve ground-based gamma-ray observatories by allowing simultaneous observation of many gamma ray sources located at different constellations.

Takahashi, Yoshiyuki

1997-01-01

219

The 28th International Cosmic Ray Conference 1 X-ray and Gamma-ray Measurements  

E-print Network

of gamma-rays has become a field of astronomy after succeeding in the reduction of overwhelming backgroundThe 28th International Cosmic Ray Conference 1 X-ray and Gamma-ray Measurements Masaki Mori and gamma-ray measurements, of the 28th International Cosmic Ray Conference. 1. Introduction Thick

Enomoto, Ryoji

220

Cosmic rays and tests of fundamental principles  

E-print Network

It is now widely acknowledged that cosmic rays experiments can test possible new physics directly generated at the Planck scale or at some other fundamental scale. By studying particle properties at energies far beyond the reach of any man-made accelerator, they can yield unique checks of basic principles. A well-known example is provided by possible tests of special relativity at the highest cosmic-ray energies. But other essential ingredients of standard theories can in principle be tested: quantum mechanics, uncertainty principle, energy and momentum conservation, effective space-time dimensions, hamiltonian and lagrangian formalisms, postulates of cosmology, vacuum dynamics and particle propagation, quark and gluon confinement, elementariness of particles... Standard particle physics or string-like patterns may have a composite origin able to manifest itself through specific cosmic-ray signatures. Ultra-high energy cosmic rays, but also cosmic rays at lower energies, are probes of both "conventional" and new Physics. Status, prospects, new ideas, and open questions in the field are discussed. The Post Scriptum shows that several basic features of modern cosmology naturally appear in a SU(2) spinorial description of space-time without any need for matter, relativity or standard gravitation. New possible effects related to the spinorial space-time structure can also be foreseen. Similarly, the existence of spin-1/2 particles can be naturally related to physics beyond Planck scale and to a possible pre-Big Bang era.

Luis Gonzalez-Mestres

2011-09-22

221

Cosmic Ray Interactions in Shielding Materials  

SciTech Connect

This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth’s surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth’s surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

2011-09-08

222

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the "knee" energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the "knee" energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

Professor Steve Reynolds

2006-02-13

223

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

Reynolds, Steve (North Carolina State University) [North Carolina State University

2006-02-13

224

Cosmic Ray Nuclei (CRN) detector investigation  

NASA Technical Reports Server (NTRS)

The Cosmic Ray Nuclei (CRN) detector was designed to measure elemental composition and energy spectra of cosmic radiation nuclei ranging from lithium to iron. CRN was flown as part of Spacelab 2 in 1985, and consisted of three basic components: a gas Cerenkov counter, a transition radiation detector, and plastic scintillators. The results of the experiment indicate that the relative abundance of elements in this range, traveling at near relativistic velocities, is similar to those reported at lower energy.

Meyer, Peter; Muller, Dietrich; Lheureux, Jacques; Swordy, Simon

1991-01-01

225

A Tale of Cosmic Rays Narrated in ? Rays by Fermi  

NASA Astrophysics Data System (ADS)

Because cosmic rays are charged particles scrambled by magnetic fields, combining direct measurements with other observations is crucial to understanding their origin and propagation. As energetic particles traverse matter and electromagnetic fields, they leave marks in the form of neutral interaction products. Among those, ? rays trace interactions of nuclei that inelastically collide with interstellar gas, as well as of leptons that undergo Bremsstrahlung and inverse-Compton scattering. Data collected by the Fermi large area telescope (LAT) are therefore telling us the story of cosmic rays along their journey from sources through their home galaxies. Supernova remnants emerge as a notable ?-ray source population, and older remnants interacting with interstellar matter finally show strong evidence of the presence of accelerated nuclei. Yet the maximum energy attained by shock accelerators is poorly constrained by observations. Cygnus X, a massive star-forming region established by the LAT as housing cosmic-ray sources, provides a test case to study the impact of wind-driven turbulence on the early propagation. Interstellar emission resulting from the large-scale propagation of cosmic rays in the Milky Way is revealed in unprecedented detail that challenges some of the simple assumptions used for the modeling. Moreover, the cosmic-ray induced ?-ray luminosities of galaxies-scale quasi-linearly with their massive-star formation rates: the overall normalization of that relation below the calorimetric limit suggests that for most systems, a substantial fraction of energy in cosmic rays escapes into the intergalactic medium. The nuclear production models and the distribution of target gas and radiation fields, not determined precisely enough yet, are key to exploiting the full potential of ?-ray data. Nevertheless, data being collected by Fermi and complementary multiwavelength/multimessenger observations are bringing us ever closer to solving the cosmic-ray mystery.

Tibaldo, Luigi

2014-10-01

226

Detectors of Cosmic Rays, Gamma Rays, and Neutrinos  

SciTech Connect

We summarize the main features, properties and performances of the typical detectors in use in Cosmic Ray Physics. A brief historical and general introduction will focus on the main classes and requirements of such detectors.

Altamirano, A. [Departamento de Fisica, Informatica y Matematicas, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia (Peru); Centro de Tecnologias de Informacion y Comunicaciones (CTIC), Universidad Nacional de Ingenieria, Lima (Peru); Navarra, G. [Dipartimento di Fisica Generale dell'Universita' and INFN, Torino (Italy)

2009-04-30

227

Research in particles and fields. [cosmic rays, gamma rays, and cosmic plasma  

NASA Technical Reports Server (NTRS)

Research activities in cosmic rays, gamma rays, and astrophysical plasmas are reviewed. Energetic particle and photon detector systems flown on spacecraft and balloons were used to carry out the investigations. Specific instruments mentioned are: the high energy isotope spectrometer telescope, the electron/isotope spectrometer, the heavy isotope spectrometer telescope, and magnetometers. Solar flares, planetary magnetospheres, element abundance, the isotopic composition of low energy cosmic rays, and heavy nuclei are among the topics receiving research attention.

Stone, E. C.; Buffington, A.; Davis, L., Jr.; Prince, T. A.; Vogt, R. E.

1984-01-01

228

PARSEC: PARametrized Simulation Engine for Cosmic rays  

NASA Astrophysics Data System (ADS)

PARSEC (PARametrized Simulation Engine for Cosmic rays) is a simulation engine for fast generation of ultra-high energy cosmic ray data based on parameterizations of common assumptions of UHECR origin and propagation. Implemented are deflections in unstructured turbulent extragalactic fields, energy losses for protons due to photo-pion production and electron-pair production, as well as effects from the expansion of the universe. Additionally, a simple model to estimate propagation effects from iron nuclei is included. Deflections in the Galactic magnetic field are included using a matrix approach with precalculated lenses generated from backtracked cosmic rays. The PARSEC program is based on object oriented programming paradigms enabling users to extend the implemented models and is steerable with a graphical user interface.

Bretz, Hans-Peter; Erdmann, Martin; Schiffer, Peter; Walz, David; Winchen, Tobias

2015-02-01

229

Cosmic ray acceleration by high velocity shocks  

NASA Astrophysics Data System (ADS)

In its simplest form, the theory of diffusive shock acceleration suggests a universal cosmic ray energy spectrum proportional to E^{-2}. The spectrum of Galactic cosmic rays is very close to a power law over many orders of magnitude, but the spectrum at source is steeper than E^{-2}. Synchrotron spectra are usually power laws but often steeper than the ?^{-0.5} implied by an E^{-2} energy spectrum. We show that the simple theory breaks down at shock velocities typical of young supernova remnants. The theoretical spectrum can be either steeper or flatter than E^{-2}. Observations that SNR radio spectra flatten with age suggest that shocks in very young SNR predominantly propagate across rather than along the magnetic field. This is consistent with the theory of magnetic field amplification. We consider this and other ways in which the microphysics of instabilities and cosmic ray transport complicate the theory of diffusive shock acceleration and lead to observable effects.

Bell, Tony; Reville, Brian; Schure, Klara

2012-07-01

230

Cosmic-ray streaming and anisotropies  

NASA Technical Reports Server (NTRS)

The paper is concerned with the differential current densities and anisotropies that exist in the interplanetary cosmic-ray gas, and in particular with a correct formulation and simple interpretation of the momentum equation that describes these on a local basis. Two examples of the use of this equation in the interpretation of previous data are given. It is demonstrated that in interplanetary space, the electric-field drifts and convective flow parallel to the magnetic field of cosmic-ray particles combine as a simple convective flow with the solar wind, and that there exist diffusive currents and transverse gradient drift currents. Thus direct reference to the interplanetary electric-field drifts is eliminated, and the study of steady-state and transient cosmic-ray anisotropies is both more systematic and simpler.

Forman, M. A.; Gleeson, L. J.

1975-01-01

231

Does electromagnetic radiation accelerate galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

Eichler, D.

1977-01-01

232

Particles and Cosmology: Learning from Cosmic Rays  

E-print Network

The density budget of the Universe is reviewed, and then specific particle candidates for non-bayonic dark matter are introduced, with emphasis on the relevance of cosmic-ray physics. The sizes of the neutrino masses indicated by recent atmospheric and solar neutrino experiments may be too small to contribute much hot dark matter. My favoured candidate for the dominant cold dark matter is the lightest supersymmetric particle, which probably weighs between about 50 GeV and about 600 GeV. Strategies to search for it via cosmic rays due to annihilations in the halo, Sun and Earth, or via direct scattering experiments, are mentioned. Possible superheavy relic particles are also discussed, in particular metastable string- or M-theory cryptons, that may be responsible for the ultra-high-energy cosmic rays. Finally, it is speculated that a non-zero contribution to the cosmological vacuum energy might result from incomplete relaxation of the quantum-gravitational vacuum.

John Ellis

1999-11-23

233

The HEAO-3 Cosmic Ray Isotope spectrometer  

NASA Technical Reports Server (NTRS)

This paper describes the Cosmic Ray Isotope instrument launched aboard the HEAO-3 satellite on September 20, 1979. The primary purpose of the experiment is to measure the isotopic composition of cosmic ray nuclei from Be-7 to Fe-58 over the energy range 0.5 to 7 GeV/nucleon. In addition charge spectra will be measured between beryllium and tin over the energy range 0.5 to 25 GeV/nucleon. The charge and isotope abundances measured by the experiment provide essential information needed to further our understanding of the origin and propagation of high energy cosmic rays. The instrument consists of 5 Cerenkov counters, a 4 element neon flash tube hodoscope and a time-of-flight system. The determination of charge and energy for each particle is based on the multiple Cerenkov technique and the mass determination will be based upon a statistical analysis of particle trajectories in the geomagnetic field.

Bouffard, M.; Engelmann, J. J.; Koch, L.; Soutoul, A.; Lund, N.; Peters, B.; Rasmussen, I. L.

1982-01-01

234

Bruno Rossi: Cosmic Ray Research 1929 - 1953  

NASA Astrophysics Data System (ADS)

Bruno Rossi, a fresh PhD from the University of Bologna, arrived in Florence in 1928. He was appointed assistant to Antonio Garbasso, professor of experimental physics. Garbosso at that time was Mayor of Florence. His days of physics were over which gave the young Rossi a freedom to follow any line of research. After some agonizing he came upon research in cosmic rays following the discovery that a large part of the cosmic rays were charged particles. Thus began a long period of creative research. Rossi had all the talents needed, a powerful intellect and the natural ability to construct apparatus that gave clear results for his experiments. I will give some examples of his many discoveries concerning the nature of cosmic rays.

Cronin, Jim

2012-03-01

235

The LDEF ultra heavy cosmic ray experiment  

NASA Technical Reports Server (NTRS)

The LDEF Ultra Heavy Cosmic Ray Experiment (UHCRE) used 16 side viewing LDEF trays giving a total geometry factor for high energy cosmic rays of 30 sq m sr. The total exposure factor was 170 sq m sr y. The experiment is based on a modular array of 192 solid state nuclear track detector stacks, mounted in sets of four in 48 pressure vessels. The extended duration of the LDEF mission has resulted in a greatly enhanced potential scientific yield from the UHCRE. Initial scanning results indicate that at least 1800 cosmic ray nuclei with Z greater than 65 were collected, including the world's first statistically significant sample of actinides. Post flight work to date and the current status of the experiment are reviewed.

Osullivan, D.; Thompson, A.; Bosch, J.; Keegan, R.; Wenzel, K.-P.; Smit, A.; Domingo, C.

1992-01-01

236

The cosmic-ray source composition  

NASA Technical Reports Server (NTRS)

The cosmic-ray source composition is shown to be related to the observed cosmic-ray abundances by a set of linear equations which are valid for either ad hoc path length distributions or quantitative solutions of galactic propagation models. In the limit of no ionization energy loss, this method is exact for all path length distributions and can replace more detailed numerical integrations; it provides a simple way to calculate directly the source composition implied by a particular set of cross sections, observed abundances, and propagation model. This method is used to determine the source abundances of the galactic cosmic rays in a model-independent manner. Compared to a simple exponential, the path length distribution required by observations is deficient in the contributions from short (not greater than 0.5 g/sq cm) paths at energies of a few GeV per nucleon.

Margolis, S. H.

1986-01-01

237

The origin of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

One century ago Viktor Hess carried out several balloon flights that led him to conclude that the penetrating radiation responsible for the discharge of electroscopes was of extraterrestrial origin. One century from the discovery of this phenomenon seems to be a good time to stop and think about what we have understood about Cosmic Rays. The aim of this review is to illustrate the ideas that have been and are being explored in order to account for the observable quantities related to cosmic rays and to summarize the numerous new pieces of observation that are becoming available. In fact, despite the possible impression that development in this field is somewhat slow, the rate of new discoveries in the last decade or so has been impressive, and mainly driven by beautiful pieces of observation. At the same time scientists in this field have been able to propose new, fascinating ways to investigate particle acceleration inside the sources, making use of multifrequency observations that range from the radio, to the optical, to X-rays and gamma rays. These ideas can now be confronted with data. I will mostly focus on supernova remnants as the most plausible sources of Galactic cosmic rays, and I will review the main aspects of the modern theory of diffusive particle acceleration at supernova remnant shocks, with special attention for the dynamical reaction of accelerated particles on the shock and the phenomenon of magnetic field amplification at the shock. Cosmic-ray escape from the sources is discussed as a necessary step to determine the spectrum of cosmic rays at the Earth. The discussion of these theoretical ideas will always proceed parallel to an account of the data being collected especially in X-ray and gamma-ray astronomy. In the end of this review I will also discuss the phenomenon of cosmic-ray acceleration at shocks propagating in partially ionized media and the implications of this phenomenon in terms of width of the Balmer line emission. This field of research has recently experienced a remarkable growth, in that H? lines have been found to bear information on the cosmic-ray acceleration efficiency of supernova shocks.

Blasi, Pasquale

2013-11-01

238

Cosmic Rays: studies and measurements before 1912  

NASA Astrophysics Data System (ADS)

The discovery of cosmic rays, a milestone in science, was based on the work by scientists in Europe and the New World and took place during a period characterised by nationalism and lack of communication. Many scientists that took part in this research a century ago were intrigued by the penetrating radiation and tried to understand the origin of it. Several important contributions to the discovery of the origin of cosmic rays have been forgotten; historical, political and personal facts might have contributed to their substantial disappearance from the history of science.

De Angelis, Alessandro

2013-06-01

239

Time variation of galactic cosmic rays  

NASA Technical Reports Server (NTRS)

Time variations in the flux of galactic cosmic rays are the result of changing conditions in the solar wind. Maximum cosmic ray fluxes, which occur when solar activity is at a minimum, are well defined. Reductions from this maximum level are typically systematic and predictable but on occasion are rapid and unexpected. Models relating the flux level at lower energy to that at neutron monitor energy are typically accurate to 20 percent of the total excursion at that energy. Other models, relating flux to observables such as sunspot number, flare frequency, and current sheet tilt are phenomenological but nevertheless can be quite accurate.

Evenson, Paul

1988-01-01

240

Cosmic-ray Muon Flux In Belgrade  

SciTech Connect

Two identical plastic scintillator detectors, of prismatic shape (50x23x5)cm similar to NE102, were used for continuous monitoring of cosmic-ray intensity. Muon {delta}E spectra have been taken at five minute intervals, simultaneously from the detector situated on the ground level and from the second one at the depth of 25 m.w.e in the low-level underground laboratory. Sum of all the spectra for the years 2002-2004 has been used to determine the cosmic-ray muon flux at the ground level and in the underground laboratory.

Banjanac, R.; Dragic, A.; Jokovic, D.; Udovicic, V. [Institute of Physics, University of Belgrade, Belgrade (Serbia and Montenegro); Puzovic, J.; Anicin, I. [Faculty of Physics, University of Belgrade, Belgrade (Serbia and Montenegro)

2007-04-23

241

The Fly's Eye Extremely High Energy Cosmic Ray Spectrum D.J. Bird,1  

E-print Network

The Fly's Eye Extremely High Energy Cosmic Ray Spectrum D.J. Bird,1 S.C. Corbato,3 H.Y. Dai,3 B present our latest results on the cosmic ray energy spectrum above 1017 eV observed by Fly's Eye. Tracks detected by both eyes can be well reconstructed and therefore have very good energy resolution

242

Cosmic Rays High Energy Particles  

E-print Network

, Neddermeyer Muon 1937 Powell Positron ! Antimatter ! 1932 Anderson Pion Cloud chambers emulsion #12;T for condensation cloud chamber / bubble chamber Cosmics Leaving OUtdoor Droplets CERN #12;T.Hebbeker Lightnings 02 02 017 018 019 020 CMS muon chamber Aachen 2002 4 cm #12;T.Hebbeker Polar Light (Aurea Borealis

Hebbeker, Thomas

243

Supernova remnants as cosmic ray accelerators. SNR IC 443  

E-print Network

We examine the hypothesis that some supernova remnants (SNRs) may be responsible for some unidentified gamma-ray sources detected by EGRET instrument aboard the Compton Gamma Ray Observatory. If this is the case, gamma-rays are produced via pion production and decay from direct inelastic collisions of accelerated by SNR shock wave ultrarelativistic protons with target protons of the interstellar medium. We develop a 3-D hydrodynamical model of SNR IC 443 as a possible cosmic gamma-ray source 2EG J0618+2234. The derived parameters of IC 443: the explosion energy E_o=2.7*10^{50} erg, the initial hydrogen number density n(0)=0.21 cm^{-3}, the mean radius R=9.6 pc and the age t=4500 yr result in too low gamma-ray flux, mainly because of the low explosion energy. Therefore, we investigate in detail the hydrodynamics of IC 443 interaction with a nearby massive molecular cloud and show that the reverse shock wave considerably increases the cosmic ray density in the interaction region. Meantime, the Rayleigh-Taylor instability of contact discontinuity between the SNR and the cloud provides an effective mixing of the containing cosmic ray plasma and the cloud material. We show that the resulting gamma-ray flux is consistent with the observational data.

B. Hnatyk; O. Petruk

1999-02-10

244

The Heliosphere and Galactic Cosmic Rays - Duration: 0:39.  

NASA Video Gallery

The heliosphere deflects galactic cosmic rays from entering the system. Galactic cosmic rays are a very high energy form of particle radiation that are extremely difficult to shield against and are...

245

Cosmic strings and ultra-high energy cosmic rays  

NASA Technical Reports Server (NTRS)

The flux is calculated of ultrahigh energy protons due to the process of cusp evaporation from cosmic string loops. For the standard value of the dimensionless cosmic string parameter epsilon is identical to G(sub mu) approx. = 10(exp -6), the flux is several orders of magnitude below the observed cosmic ray flux of ultrahigh energy protons. However, the flux at any energy initially increases as the value of epsilon is decreased. This at first suggests that there may be a lower limit on the value of epsilon, which would imply a lower limit on the temperature of a cosmic string forming phase transition in the early universe. However, the calculation shows that this is not the case -- the particle flux at any energy reaches its highest value at epsilon approx. = 10(exp -15) and it then decreases for further decrease of the value of epsilon. This is due to the fact that for too small values of epsilon (less than 10(exp -15)), the energy loss of the loops through the cusp evaporation process itself (rather than gravitational energy loss of the loops) becomes the dominant factor that controls the behavior of the number density of the loops at the relevant times of emission of the particles. The highest flux at any energy remains at least four orders of magnitude below the observed flux. There is thus no lower limit on epsilon.

Bhattacharjee, Pijushpani

1989-01-01

246

A note on the hydrodynamical description of cosmic ray propagation  

NASA Astrophysics Data System (ADS)

The set of hydrodynamic equations governing a system of cosmic rays, waves and background plasma, is derived. The cosmic rays interact with the background plasma via hydromagnetic waves (e.g., Alfven waves) which in turn are produced by the cosmic ray streaming instability. The convection, diffusion and second order Fermi effect of the cosmic rays are taken into account. A simple example emphasizing the second order Fermi effect is given.

Ko, C.-M.

1992-06-01

247

Empirical model for the Earth's cosmic ray shadow at 400 KM: Prohibited cosmic ray access  

Microsoft Academic Search

The possibility to construct a unit sphere of access that describes the cosmic radiation allowed to an Earth-orbiting spacecraft is discussed. It is found that it is possible to model the occluded portion of the cosmic ray sphere of access as a circular projection with a diameter bounded by the satellite-Earth horizon. Maintaining tangency at the eastern edge of the

J. E. Humble; D. F. Smart; M. A. Shea

1985-01-01

248

Angular correlation of cosmic neutrinos with ultrahigh-energy cosmic rays and implications for their sources  

E-print Network

Cosmic neutrino events detected by the IceCube Neutrino Observatory with energy $\\gtrsim 30$ TeV have poor angular resolutions to reveal their origin. Ultrahigh-energy cosmic rays (UHECRs), with better angular resolutions at $>60$ EeV energies, can be used to check if the same astrophysical sources are responsible for producing both neutrinos and UHECRs. We test this hypothesis, with statistical methods which emphasize invariant quantities, by using data from the Pierre Auger Observatory, Telescope Array and past cosmic-ray experiments. We find that the arrival directions of the cosmic neutrinos are correlated with $\\ge 100$ EeV UHECR arrival directions at confidence level $\\approx 93\\%$. The strength of the correlation decreases with decreasing UHECR energy and no correlation exists at energy $\\sim 60$ EeV. A search in astrophysical databases within $3^\\circ$ of the arrival directions of UHECRs with energy $\\ge 100$ EeV, that are correlated with the IceCube cosmic neutrinos, resulted in 18 sources from the Swift-BAT X-ray catalog with redshift $z\\le 0.06$. We also found 3 objects in the K\\"uhr catalog of radio sources using the same criteria. The sources are dominantly Seyfert galaxies with Cygnus A being the most prominent member. We calculate the required neutrino and UHECR fluxes to produce the observed correlated events, and estimate the corresponding neutrino luminosity (25 TeV-2.2 PeV) and cosmic-ray luminosity (500 TeV-180 EeV), assuming the sources are the ones we found in the Swift-BAT and K\\"uhr catalogs. We compare these luminosities with the X-ray luminosity of the corresponding sources and discuss possibilities of accelerating protons to $\\gtrsim 100$ EeV and produce neutrinos in these sources.

Reetanjali Moharana; Soebur Razzaque

2015-01-21

249

Cosmic Rays for Heliospheric Space Weather Storm Prediction  

NASA Astrophysics Data System (ADS)

The classical imaging of CME's by solar UV light is successfully applied on many satellites like for instance on SOHO, STEREO A and B or SDO. CME detection via UV light from ground based telescopes can't be carried out, because of the absorption of UV light in the Earth atmosphere. However CME detection is done on ground by means of cosmic ray muon telescopes in the Global Muon Detection Network (GMDN). Therefore the astrophysics and solar physics for GMDN are summarized in chapter 1. GMDN data and results are described in chapter 2. A space situational awareness (SSA) satellite, which has also the purpose of CME imaging by means of a telescope for cosmic rays are sketched in chapter 3.

Jansen, Frank; Behrens, Jörg

2011-06-01

250

Microphysics of Cosmic Ray Driven Plasma Instabilities  

NASA Astrophysics Data System (ADS)

Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

Bykov, A. M.; Brandenburg, A.; Malkov, M. A.; Osipov, S. M.

2013-10-01

251

Microphysics of Cosmic Ray Driven Plasma Instabilities  

NASA Astrophysics Data System (ADS)

Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

Bykov, A. M.; Brandenburg, A.; Malkov, M. A.; Osipov, S. M.

252

Terrestrial Magnetism and Cosmic Rays  

Microsoft Academic Search

IT has been shown by several observers within the last few years that the ionisation caused by cosmic radiation, when reduced to the same barometric pressure, is not constant. In addition to a very small regular diurnal variation, the existence of which has been proved by continuous registration over a period of three years at 2,300 metres above sea-level1, much

Victor F. Hess; Wolfram Illing

1935-01-01

253

Measurement of the cosmic ray spectrum above $4{\\times}10^{18}$ eV using inclined events detected with the Pierre Auger Observatory  

E-print Network

A measurement of the cosmic-ray spectrum for energies exceeding $4{\\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\\gamma}$ with index $\\gamma=2.70 \\pm 0.02 \\,\\text{(stat)} \\pm 0.1\\,\\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\\text{s}=(5.12\\pm0.25\\,\\text{(stat)}^{+1.0}_{-1.2}\\,\\text{(sys)}){\\times}10^{19}$ eV.

The Pierre Auger Collaboration; Alexander Aab; Pedro Abreu; Marco Aglietta; Eun-Joo Ahn; Imen Al Samarai; Ivone Albuquerque; Ingomar Allekotte; Patrick Allison; Alejandro Almela; Jesus Alvarez Castillo; Jaime Alvarez-Muñiz; Rafael Alves Batista; Michelangelo Ambrosio; Amin Aminaei; Luis Anchordoqui; Sofia Andringa; Carla Aramo; Victor Manuel Aranda; Fernando Arqueros; Nicusor Arsene; Hernán Gonzalo Asorey; Pedro Assis; Julien Aublin; Maximo Ave; Michel Avenier; Gualberto Avila; Nafiun Awal; Alina Mihaela Badescu; Kerri B Barber; Julia Bäuml; Colin Baus; Jim Beatty; Karl Heinz Becker; Jose A Bellido; Corinne Berat; Mario Edoardo Bertaina; Xavier Bertou; Peter Biermann; Pierre Billoir; Simon G Blaess; Alberto Blanco; Miguel Blanco; Carla Bleve; Hans Blümer; Martina Bohá?ová; Denise Boncioli; Carla Bonifazi; Nataliia Borodai; Jeffrey Brack; Iliana Brancus; Ariel Bridgeman; Pedro Brogueira; William C Brown; Peter Buchholz; Antonio Bueno; Stijn Buitink; Mario Buscemi; Karen S Caballero-Mora; Barbara Caccianiga; Lorenzo Caccianiga; Marina Candusso; Laurentiu Caramete; Rossella Caruso; Antonella Castellina; Gabriella Cataldi; Lorenzo Cazon; Rosanna Cester; Alan G Chavez; Andrea Chiavassa; Jose Augusto Chinellato; Jiri Chudoba; Marco Cilmo; Roger W Clay; Giuseppe Cocciolo; Roberta Colalillo; Alan Coleman; Laura Collica; Maria Rita Coluccia; Ruben Conceição; Fernando Contreras; Mathew J Cooper; Alain Cordier; Stephane Coutu; Corbin Covault; James Cronin; Richard Dallier; Bruno Daniel; Sergio Dasso; Kai Daumiller; Bruce R Dawson; Rogerio M de Almeida; Sijbrand J de Jong; Giuseppe De Mauro; Joao de Mello Neto; Ivan De Mitri; Jaime de Oliveira; Vitor de Souza; Luis del Peral; Olivier Deligny; Hans Dembinski; Niraj Dhital; Claudio Di Giulio; Armando Di Matteo; Johana Chirinos Diaz; Mary Lucia Díaz Castro; Francisco Diogo; Carola Dobrigkeit; Wendy Docters; Juan Carlos D'Olivo; Alexei Dorofeev; Qader Dorosti Hasankiadeh; Maria Teresa Dova; Jan Ebr; Ralph Engel; Martin Erdmann; Mona Erfani; Carlos O Escobar; Joao Espadanal; Alberto Etchegoyen; Heino Falcke; Ke Fang; Glennys Farrar; Anderson Fauth; Norberto Fazzini; Andrew P Ferguson; Mateus Fernandes; Brian Fick; Juan Manuel Figueira; Alberto Filevich; Andrej Filip?i?; Brendan Fox; Octavian Fratu; Martín Miguel Freire; Benjamin Fuchs; Toshihiro Fujii; Beatriz García; Diego Garcia-Pinto; Florian Gate; Hartmut Gemmeke; Alexandru Gherghel-Lascu; Piera Luisa Ghia; Ugo Giaccari; Marco Giammarchi; Maria Giller; Dariusz G?as; Christian Glaser; Henry Glass; Geraldina Golup; Mariano Gómez Berisso; Primo F Gómez Vitale; Nicolás González; Ben Gookin; Jacob Gordon; Alessio Gorgi; Peter Gorham; Philippe Gouffon; Nathan Griffith; Aurelio Grillo; Trent D Grubb; Fausto Guarino; Germano Guedes; Matías Rolf Hampel; Patricia Hansen; Diego Harari; Thomas A Harrison; Sebastian Hartmann; John Harton; Andreas Haungs; Thomas Hebbeker; Dieter Heck; Philipp Heimann; Alexander E Herve; Gary C Hill; Carlos Hojvat; Nicholas Hollon; Ewa Holt; Piotr Homola; Jörg Hörandel; Pavel Horvath; Miroslav Hrabovský; Daniel Huber; Tim Huege; Antonio Insolia; Paula Gina Isar; Ingolf Jandt; Stefan Jansen; Cecilia Jarne; Jeffrey A Johnsen; Mariela Josebachuili; Alex Kääpä; Olga Kambeitz; Karl Heinz Kampert; Peter Kasper; Igor Katkov; Balazs Kégl; Bianca Keilhauer; Azadeh Keivani; Ernesto Kemp; Roger Kieckhafer; Hans Klages; Matthias Kleifges; Jonny Kleinfeller; Raphael Krause; Nicole Krohm; Oliver Krömer; Daniel Kuempel; Norbert Kunka; Danielle LaHurd; Luca Latronico; Robert Lauer; Markus Lauscher; Pascal Lautridou; Sandra Le Coz; Didier Lebrun; Paul Lebrun; Marcelo Augusto Leigui de Oliveira; Antoine Letessier-Selvon; Isabelle Lhenry-Yvon; Katrin Link; Luis Lopes; Rebeca López; Aida López Casado; Karim Louedec; Lu Lu; Agustin Lucero; Max Malacari; Simone Maldera; Manuela Mallamaci; Jennifer Maller; Dusan Mandat; Paul Mantsch; Analisa Mariazzi; Vincent Marin; Ioana Mari?; Giovanni Marsella; Daniele Martello; Lilian Martin; Humberto Martinez; Oscar Martínez Bravo; Diane Martraire; Jimmy Masías Meza; Hermann-Josef Mathes; Sebastian Mathys; James Matthews; John Matthews; Giorgio Matthiae; Detlef Maurel; Daniela Maurizio; Eric Mayotte; Peter Mazur; Carlos Medina; Gustavo Medina-Tanco; Rebecca Meissner; Victor Mello; Diego Melo; Alexander Menshikov; Stefano Messina; Rishi Meyhandan; Maria Isabel Micheletti; Lukas Middendorf; Ignacio A Minaya; Lino Miramonti; Bogdan Mitrica; Laura Molina-Bueno; Silvia Mollerach; François Montanet; Carlo Morello; Miguel Mostafá; Celio A Moura; Marcio Aparecido Muller; Gero Müller; Sarah Müller

2015-03-26

254

Measurement of the cosmic ray spectrum above $4{\\times}10^{18}$ eV using inclined events detected with the Pierre Auger Observatory  

E-print Network

A measurement of the cosmic-ray spectrum for energies exceeding $4{\\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\\gamma}$ with index $\\gamma=2.70 \\pm 0.02 \\,\\text{(stat)} \\pm 0.1\\,\\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\\text{s}=(5.12\\pm0.25\\,\\text{(stat)}^{+1.0}_{-1.2}\\,\\text{(sys)}){\\times}10^{19}$ eV.

,

2015-01-01

255

High Energy X-Ray Detection OF G359.89-0.08 (Sgr A-E): Magnetic Flux Tube Emission Powered By Cosmic Rays?  

E-print Network

We report the first detection of high-energy X-ray (E>10 keV) emission from the Galactic Center non-thermal filament G359.89-0.08 (Sgr A-E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The bright filament was detected up to ~50 keV during a NuSTAR Galactic Center monitoring campaign. The featureless power-law spectrum with a photon index of ~2.3 confirms a non-thermal emission mechanism. The observed flux in the 3-79 keV band is ~ 2.0e-12 erg/cm^2/s, corresponding to an unabsorbed X-ray luminosity of ~2.6e34 erg/s assuming a distance of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A-E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps TeV electrons. We propose two possible TeV electron sources: old PWNe (up to ~100 kyr) with low surface brightness and radii up to ~30 pc or molecular clouds (MC...

Zhang, Shuo; Baganoff, Frederick K; Bauer, Franz E; Boggs, Steven E; Craig, William W; Christensen, Finn E; Gotthelf, Eric V; Harrison, Fiona A; Mori, Kaya; Nynka, Melania; Stern, Daniel; Tomsick, John A; Zhang, William W

2014-01-01

256

Cosmic Rays Astrophysics: The Discipline, Its Scope, and Its Applications  

NASA Technical Reports Server (NTRS)

This slide presentation gives an overview of the discipline surrounding cosmic ray astrophysics. It includes information on recent assertions surrounding cosmic rays, exposure levels, and a short history with specific information on the origin, acceleration, transport, and modulation of cosmic rays.

Barghouty, A. F.

2009-01-01

257

Underground cosmic-ray experiment EMMA T. Enqvista  

E-print Network

Underground cosmic-ray experiment EMMA T. Enqvista , J. Joutsenvaaraa , T. J¨ams´enb , P. Ker A new cosmic-ray experiment is under construction in the Pyh¨asalmi mine, Finland. It aims to study the chem- ical composition of cosmic rays at and above the knee region. The array, called EMMA, will cover

Usoskin, Ilya G.

258

The proposed connection between clouds and cosmic rays: Cloud  

E-print Network

The proposed connection between clouds and cosmic rays: Cloud behaviour during the past 50 of galactic cosmic rays (GCR) and cloudiness. Here we review the evidence for such a connection from studies for the low cloud decrease predicted by the rising levels of solar activity and the low cloud­cosmic ray flux

259

Cosmic Ray Pitch Angle Scattering Through 90 o  

E-print Network

Cosmic Ray Pitch Angle Scattering Through 90 o G.M. Felice 1 and R.M. Kulsrud 2 Princeton Plasma #12; -- 2 -- ABSTRACT We study the problem of cosmic ray di#usion in the galactic disk with particu in momentum space by wave­particle mirror interaction (here v # is the cosmic ray velocity parallel

260

LINK BETWEEN COSMIC RAYS AND CLOUDS ON DIFFERENT TIME SCALES  

E-print Network

LINK BETWEEN COSMIC RAYS AND CLOUDS ON DIFFERENT TIME SCALES ILYA G. USOSKIN and GENNADY A is related to a link between the cosmic ray flux and cloudiness. Here we review evidences relating terrestrial climate variability to changes of cosmic ray flux in the Earth's vicinity on different time scales

Usoskin, Ilya G.

261

Testing fundamental principles with high-energy cosmic rays  

E-print Network

Testing fundamental principles with high-energy cosmic rays Luis Gonzalez-Mestres LAPP, Université_sci@yahoo.fr It is not yet clear [1] whether the observed flux suppression for ultra-high energy cosmic rays (UHECR to violations of standard special relativity modifying cosmic- ray propagation or acceleration at very high

262

Early Cosmic Ray Research In France Olivier Ravela  

E-print Network

Early Cosmic Ray Research In France Olivier Ravela a SUBATECH, Ecole des Mines de Nantes, IN2P3/CNRS, Université de Nantes, France Abstract. The French research on cosmic rays in the first half of the 20th century is summarized. The main experiments are described as the discovery of air cosmic ray

Paris-Sud XI, Université de

263

Anisotropy of Arrival Directions of Ultrahigh Energy Cosmic Rays  

E-print Network

Anisotropy of Arrival Directions of Ultrahigh Energy Cosmic Rays Chad Barrett Finley Submitted;ABSTRACT Anisotropy of Arrival Directions of Ultrahigh Energy Cosmic Rays Chad Barrett Finley This thesis investigates the origins of ultrahigh energy cosmic rays by searching for evidence of small-scale anisotropy

264

The detection of a cosmic-ray electron-positron anisotropy is a sufficient (but not necessary) condition to discard a Dark Matter origin for the anomalous positron fraction  

E-print Network

I demonstrate that if an anisotropy in the arrival direction of high-energy cosmic-ray electrons and positrons is observed, then dark matter annihilation is ruled out as an explanation to the positron excess. For an observable anisotropy to originate from dark matter annihilation, the high-energy electrons and positrons must be produced in a nearby clump. I consider the annihilation pathway producing the smallest flux of gamma rays versus electrons and positrons, and the combination of clump distance and luminosity that minimizes the gamma-ray flux. I show that if an anisotropy from such a clump were detected, then the clump would be clearly detectable as an anomalous, bright gamma-ray source with the Fermi Large Area Telescope. I also point out that the non-detection of an anisotropy is perfectly compatible with an astrophysical origin for the excess positrons that has nothing to do with dark matter.

Profumo, Stefano

2014-01-01

265

Cosmic ray fluctuations in compressible turbulent medium  

Microsoft Academic Search

The influence of compressibility of the medium on cosmic ray (CR) fluctuations has been investigated. The CR transport equation has been used to obtain an equation for the second moment of CR particle density (correlation function of the particle density). It is shown that the effects due to the compressibility of the medium has an essential influence on CR fluctuations.

M. Katz; M. Stehlik; N. Yacobi

1995-01-01

266

Clusters in Very High Energy Cosmic Rays  

E-print Network

Arrival directions of cosmic rays with the energy E>4.10^{19} eV are analyzed by using data of the Yakutsk and AGASA (Japan) extensive air showers (EAS) arrays. It is supposed that the clusters can be formed as a result of decay of superheavy particles. The consequences of this supposition compare with experimental data.

A. A. Mikhailov

2004-03-19

267

Numerical likelihood analysis of cosmic ray anisotropies  

SciTech Connect

A numerical likelihood approach to the determination of cosmic ray anisotropies is presented which offers many advantages over other approaches. It allows a wide range of statistically meaningful hypotheses to be compared even when full sky coverage is unavailable, can be readily extended in order to include measurement errors, and makes maximum unbiased use of all available information.

Carlos Hojvat et al.

2003-07-02

268

Anisotropies in Ultrahigh Energy Cosmic Rays  

E-print Network

The present status of anisotropy studies for the highest energy cosmic rays is presented including the first full sky survey. Directions and prospects for the future are also discussed in light of new statistical methods and the last quantities of data expected in the near future from the Pierre Auger Observatory.

John Swain

2004-01-30

269

Green River Community College Cosmic Ray Detector  

Microsoft Academic Search

The Washington Area Large scale Time coincidence Array (WALTA) researches high-energy cosmic ray and has placed particle detector arrays around the Seattle area to increase the accuracy of muon information. Green River Community College is one of the schools in collaboration with WALTA and offers its students under-graduate research by working with the particle detector arrays, data collecting and reporting.

Andrea Roma; Crissy Harrington; Mirela Isic; Andrew Adams; Ron Draper

2008-01-01

270

Heliospheric Physics and Cosmic Rays Lecture notes  

E-print Network

verified that the cloud chamber tracks are curved. This showed that CR are charged particles. 1937: Seth of ionisation were charged particles de- flected by the geomagnetic field. 1929: Using a newly invented cloud chamber, D. Skobelzyn observed the first ghostly tracks left by cosmic rays. 1929: Bothe and Kolhorster

Usoskin, Ilya G.

271

COSMIC-RAY NEUTRON ENERGY SPECTRUM  

Microsoft Academic Search

The cosmic-ray neutron energy spectrum in the equilibrium region of the ; atmosphere was measured with several different calibrated detectors from thermal ; energies to about 1 Bev at 44 deg north magnetic latitude and up to 40,000 feet. ; By combination of the data from these measurements with those from other ; experiments, a complete differential energy spectrum is

Wilmot Hess; H. W. Patterson; Roger Wallace; Edward Chupp

1959-01-01

272

Exotic physics with ultrahigh energy cosmic rays  

E-print Network

Ultrahigh energy cosmic rays provide a unique ground for probing new physics. In this talk we review the possibility of testing TeV gravity in interactions of cosmogenic neutrinos and the potential to discover long-lived exotic particles in nucleon-produced air showers, such as gluinos of split-SUSY models or staus of supersymmetric models with a gravitino LSP.

M. Ahlers; J. I. Illana; M. Masip; D. Meloni

2007-10-02

273

Cosmic Ray Transport in the Distant Heliosheath  

NASA Technical Reports Server (NTRS)

The character of energetic particle transport in the distant heliosheath and especially in the vicinity of the heliopause could be quite distinct from the other regions of the heliosphere. The magnetic field structure is dominated by a tightly wrapped oscillating heliospheric current sheet which is transported to higher latitudes by the nonradial heliosheath flows. Both Voyagers have, or are expected to enter a region dominated by the sectored field formed during the preceding solar maximum. As the plasma flow slows down on approach to the heliopause, the distance between the folds of the current sheet decreases to the point where it becomes comparable to the cyclotron radius of an energetic ion, such as a galactic cosmic ray. Then, a charged particle can effectively drift across a stack of magnetic sectors with a speed comparable with the particle s velocity. Cosmic rays should also be able to efficiently diffuse across the mean magnetic field if the distance between sector boundaries varies. The region of the heliopause could thus be much more permeable to cosmic rays than was previously thought. This new transport proposed mechanism could explain the very high intensities (approaching the model interstellar values) of galactic cosmic rays measured by Voyager 1 during 2010-2011.

Florinski, V.; Adams, James H.; Washimi, H.

2011-01-01

274

A database of charged cosmic rays  

NASA Astrophysics Data System (ADS)

Aims: This paper gives a description of a new online database and associated online tools (data selection, data export, plots, etc.) for charged cosmic-ray measurements. The experimental setups (type, flight dates, techniques) from which the data originate are included in the database, along with the references to all relevant publications. Methods: The database relies on the MySQL5 engine. The web pages and queries are based on PHP, AJAX and the jquery, jquery.cluetip, jquery-ui, and table-sorter third-party libraries. Results: In this first release, we restrict ourselves to Galactic cosmic rays with Z ? 30 and a kinetic energy per nucleon up to a few tens of TeV/n. This corresponds to more than 200 different sub-experiments (i.e., different experiments, or data from the same experiment flying at different times) in as many publications. Conclusions: We set up a cosmic-ray database (CRDB) and provide tools to sort and visualise the data. New data can be submitted, providing the community with a collaborative tool to archive past and future cosmic-ray measurements. http://lpsc.in2p3.fr/crdb; Contact: crdatabase@lpsc.in2p3.fr

Maurin, D.; Melot, F.; Taillet, R.

2014-09-01

275

A Cannonball Model of Cosmic Rays  

E-print Network

I outline a "Cannon-Ball" model of Cosmic Rays in which their distribution in the Galaxy, their total "luminosity", the broken power-law spectra with their observed slopes, the position of the knee(s) and ankle(s), and the alleged variations of composition with energy are all explained in terms of simple and "standard" physics.

A. De Rujula

2004-12-07

276

TWO COMPONENTS OF COSMIC-RAY MODULATION  

Microsoft Academic Search

The long-term modulation of galactic cosmic rays is investigated from 1957 up to 1992 analysing the dynamic and the quasi-stationary components, separately. It has been found that the dynamic component is characterized by the presence of two peaks at the maximum phase of each solar activity cycle. We infer that the time interval between the two peaks corresponds to a

M. Storini; S. Pase; J. Sykora; M. Parisi

1997-01-01

277

Gamma-ray astronomy and the origin of cosmic rays  

NASA Technical Reports Server (NTRS)

New surveys of galactic gamma ray emission together with millimeter wave radio surveys indicated that cosmic rays were produced as the result of supernova explosions in our galaxy with the most intense production occurring in a Great Galactic Ring about 35,000 light years in diameter where supernova remnants and pulsars were concentrated.

Stecker, F. W.

1978-01-01

278

Cosmic-ray ionisation in collapsing clouds  

NASA Astrophysics Data System (ADS)

Context. Cosmic rays play an important role in dense molecular cores, affecting their thermal and dynamical evolution and initiating the chemistry. Several studies have shown that the formation of protostellar discs in collapsing clouds is severely hampered by the braking torque exerted by the entrained magnetic field on the infalling gas, as long as the field remains frozen to the gas. Aims: In this paper we examine the possibility that the concentration and twisting of the field lines in the inner region of collapse can produce a significant reduction of the ionisation fraction. Methods: To check whether the cosmic-ray ionisation rate can fall below the critical value required to maintain good coupling, we first study the propagation of cosmic rays in a model of a static magnetised cloud varying the relative strength of the toroidal/poloidal components and the mass-to-flux ratio. We then follow the path of cosmic rays using realistic magnetic field configurations generated by numerical simulations of a rotating collapsing core with different initial conditions. Results: We find that an increment of the toroidal component of the magnetic field, or, in general, a more twisted configuration of the field lines, results in a decrease in the cosmic-ray flux. This is mainly due to the magnetic mirroring effect that is stronger where larger variations in the field direction are present. In particular, we find a decrease of the cosmic-ray ionisation rate below 10-18 s-1 in the central 300-400 AU, where density is higher than about 109 cm-3. This very low value of the ionisation rate is attained in the cases of intermediate and low magnetisation (mass-to-flux ratio ? = 5 and 17, respectively) and for toroidal fields larger than about 40% of the total field. Conclusions: Magnetic field effects can significantly reduce the ionisation fraction in collapsing clouds. We provide a handy fitting formula to compute approximately the attenuation of the cosmic-ray ionisation rate in a molecular cloud as a function of the density and the magnetic configuration.

Padovani, M.; Hennebelle, P.; Galli, D.

2013-12-01

279

In Search of Cosmic Rays: A Student Physics Project Aimed at Finding the Origin of Cosmic Rays.  

ERIC Educational Resources Information Center

Describes an ongoing project, the Cosmic Ray Observatory Project (CROP), being conducted by the University of Nebraska in partnership with several high schools. Each school group has installed cosmic ray detectors, and initial activities have included calibrating equipment, gathering preliminary data, and learning about cosmic ray showers. Aims to…

Antonelli, Jamie; Mahoney, Sean; Streich, Derek; Liebl, Michael

2001-01-01

280

Supernova Remnants as the Sources of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

The origin of cosmic rays holds still many mysteries hundred years after they were first discovered. Supernova remnants have for long been the most likely sources of Galactic cosmic rays. I discuss here some recent evidence that suggests that supernova remnants can indeed efficiently accelerate cosmic rays. For this conference devoted to the Astronomical Institute Utrecht I put the emphasis on work that was done in my group, but placed in a broader context: efficient cosmic-ray acceleration and the implications for cosmic-ray escape, synchrotron radiation and the evidence for magnetic-field amplification, potential X-ray synchrotron emission from cosmic-ray precursors, and I conclude with the implications of cosmic-ray escape for a Type Ia remnant like Tycho and a core-collapse remnant like Cas A.

Vink, J.

2013-01-01

281

Concerning the Nature of the Cosmic Ray Power Law Exponents  

E-print Network

We have recently shown that the cosmic ray energy distributions as detected on earthbound, low flying balloon or high flying satellite detectors can be computed by employing the heats of evaporation of high energy particles from astrophysical sources. In this manner, the experimentally well known power law exponents of the cosmic ray energy distribution have been theoretically computed as 2.701178 for the case of ideal Bose statistics, 3.000000 for the case of ideal Boltzmann statistics and 3.151374 for the case of ideal Fermi statistics. By "ideal" we mean virtually zero mass (i.e. ultra-relativistic) and noninteracting. These results are in excellent agreement with the experimental indices of 2.7 with a shift to 3.1 at the high energy ~ PeV "knee" in the energy distribution. Our purpose here is to discuss the nature of cosmic ray power law exponents obtained by employing conventional thermal quantum field theoretical models such as quantum chromodynamics to the cosmic ray sources in a thermodynamic scheme wherein gamma and zeta function regulation is employed. The key reason for the surprising accuracy of the ideal boson and ideal fermion cases resides in the asymptotic freedom or equivalently the Feynman "parton" structure of the ultra-high energy tails of spectral functions.

A. Widom; J. Swain; Y. N. Srivastava

2015-02-07

282

TRACING THE SOURCES OF COSMIC RAYS WITH MOLECULAR IONS  

SciTech Connect

The rate of ionization by cosmic rays (CRs) in interstellar gas directly associated with {gamma}-ray-emitting supernova remnants (SNRs) is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of ionization-induced chemistry yields the first quantitative prediction of the astrophysical H{sup +} {sub 2} emission line spectrum, which should be detectable together with H{sup +} {sub 3} lines. The predicted coincident observation of those emission lines and {gamma}-rays will help prove that SNRs are sources of CRs.

Becker, Julia K.; Schuppan, Florian [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik IV, D-44780 Bochum (Germany); Black, John H.; Mohammadtaher Safarzadeh, E-mail: julia@tp4.rub.de [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden)

2011-10-01

283

Ultra-High Energy Cosmic Rays Detected by the Pierre Auger Observatory: First Direct Evidence, and its Implications, that a Subset Originate in Nearby Radiogalaxies  

E-print Network

(abridged) The Pierre Auger Collaboration has reported 27 Ultra-High Energy Cosmic Ray Events (UHECRs) with energies above 56 EeV and well determined arrival directions as of 2007 August 31. They find that the arrival directions are not isotropic, but instead appear correlated with the positions of nearby AGNs. Our aim was to determine the sources of these UHECRs by comparing their arrival directions with more comprehensive source catalogs. Four (eight) of the 27 UHECRs with energy >56EeV detected by the Pierre Auger Observatory have arrival directions within 1.5deg (3.5deg) of the extended (>180kpc) radio structures of nearby radiogalaxies or the single nearby BLLac with extended radio structure. Conversely the radio structures of three (six) of all ten nearest extended radiogalaxies are within 1.5deg (3.5deg) of a UHECR; three of the remaining four radiogalaxies are in directions with lower exposure times. This correlation between nearby extended radiogalaxies and a subset of UHECRs is significant at the 99.9% level. This is the first direct observational proof that radio galaxies are a significant source of UHECRs. For the remaining ~20 UHECRs, an isotropic distribution cannot be ruled out at high significance. The correlation found by the Auger Collaboration between the 27 UHECRs and AGNs in the Veron-Cetty & Veron catalog at D < 71Mpc has a much lower significance when one considers only the ~20 UHECRs not `matched' to nearby extended radiogalaxies. No correlation is seen between UHECRs and supernovae, supernova remnants, nearby galaxies, or nearby groups and clusters of galaxies. The primary difference between the UHECR detections at the Pierre Auger Observatory and previous experiments may thus be that the Southern Hemisphere is more privileged with respect to nearby extended radiogalaxies.

Neil M. Nagar; Javier Matulich

2008-06-19

284

Angular correlation of cosmic neutrinos with ultrahigh-energy cosmic rays and implications for their sources  

E-print Network

Cosmic neutrino events detected by the IceCube Neutrino Observatory with energy $\\gtrsim 30$ TeV have poor angular resolutions to reveal their origin. Ultrahigh-energy cosmic rays (UHECRs), with better angular resolutions at $>60$ EeV energies, can be used to check if the same astrophysical sources are responsible for producing both neutrinos and UHECRs. We test this hypothesis, with statistical methods which emphasize invariant quantities, by using data from the Pierre Auger Observatory, Telescope Array and past cosmic-ray experiments. We find that the arrival directions of the cosmic neutrinos are correlated with $\\ge 100$ EeV UHECR arrival directions at confidence level $\\approx 93\\%$. The strength of the correlation decreases with decreasing UHECR energy and no correlation exists at energy $\\sim 60$ EeV. A search in astrophysical databases within $3^\\circ$ of the arrival directions of UHECRs with energy $\\ge 100$ EeV, that are correlated with the IceCube cosmic neutrinos, resulted in 18 sources from the S...

Moharana, Reetanjali

2015-01-01

285

Ninteenth International Cosmic Ray Conference. OG Sessions, Volume 1  

NASA Technical Reports Server (NTRS)

Contributed papers addressing cosmic ray origin and galactic phenomena are compiled. The topic areas covered in this volume include gamma ray bursts, gamma rays from point sources, and diffuse gamma ray emission.

Jones, F. C. (compiler)

1985-01-01

286

Constraining the Low-Energy Cosmic Ray Spectrum  

Microsoft Academic Search

While the cosmic ray spectrum is easily observed at high energies, below about 100 MeV cosmic rays are excluded from the inner solar system by the magnetic field coupled to the solar wind. This means that the cosmic ray spectrum below 100 MeV cannot be directly observed. However, there are several secondary observables which can tell us about low-energy cosmic

Nick Indriolo; B. D. Fields; B. J. McCall

2008-01-01

287

Neutrinos associated with cosmic rays of top-down origin  

NASA Astrophysics Data System (ADS)

Top-down models of cosmic rays produce more neutrinos than photons and more photons than protons. In these models, we reevaluate the fluxes of neutrinos associated with the highest energy cosmic rays in light of mounting evidence that they are protons and not gamma rays. While proton dominance at EeV energies can possibly be achieved by efficient absorption of the dominant high-energy photon flux on universal and galactic photon and magnetic background fields, we show that the associated neutrino flux is inevitably increased to a level where it might be within reach of operating experiments such as AMANDA II, RICE and AGASA. In future neutrino telescopes, tens to a hundred, rather than a few neutrinos per kilometer squared per year, may be detected above 100 TeV.

Barbot, C.; Drees, M.; Halzen, F.; Hooper, D.

2003-02-01

288

Elemental technetium and promethium as cosmic-ray clocks  

NASA Technical Reports Server (NTRS)

The possibility of using elemental Tc (Z = 43) and Pm (Z = 61) as clocks to measure the mean cosmic-ray confinement time in the Galaxy, tau(epsilon) is considered. For this purpose it is necessary to estimate the unknown beta(+) decay half-lives of several Tc and Pm isotopes; these estimates are obtained using beta-decay systematics. In the case of Tc it is possible to estimate the half-lives sufficiently well and show that this element can indeed be used as a cosmic-ray clock; in the case of Pm the half-lives are too uncertain to permit any conclusion. In order to make meaningful measurement of tau(epsilon) using elemental Tc, a comsic-ray detector must have a charge resolution less than about 0.25e in the region around Tc, and enough collecting power to detect a few hundred Tc nuclei.

Drach, J.; Salamon, M. H.

1987-01-01

289

The Interaction of Cosmic Rays with Diffuse Clouds  

E-print Network

We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray induced heating via Alfven-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The general analysis method outlined here can apply to diffuse clouds in either the ionized interstellar medium or in galactic winds. We introduce a general-purpose model of cosmic-ray diffusion building upon the hydrodynamic approximation for cosmic rays (from McKenzie & Voelk and Breitschwerdt and collaborators). Our improved method self-consistently derives the cosmic-ray flux and diffusivity under the assumption that the streaming instability is the dominant mechanism for setting the cosmic-ray flux and diffusion. We find that, as expected, cosmic rays do not couple to gas within cool clouds (cosmic rays exert no forces inside of cool clouds), that the cosmic-ray density does not increase within clouds (it may slightly decrease in general, and decrease by an order of mag...

Everett, John E

2011-01-01

290

Cosmic-ray Exposure Ages of Meteorites  

NASA Astrophysics Data System (ADS)

The classic idea of a cosmic-ray exposure (CRE) age for a meteorite is based on a simple but useful picture of meteorite evolution, the one-stage irradiation model. The precursor rock starts out on a parent body, buried under a mantle of material many meters thick that screens out cosmic rays. At a time ti, a collision excavates a precursor rock - a "meteoroid." The newly liberated meteoroid, now fully exposed to cosmic rays, orbits the Sun until a time tf, when it strikes the Earth, where the overlying blanket of air (and possibly of water or ice) again shuts out almost all cosmic rays (cf. Masarik and Reedy, 1995). The quantity tf-ti is called the CRE age, t. To obtain the CRE age of a meteorite, we measure the concentrations in it of one or more cosmogenic nuclides (Table 1), which are nuclides that cosmic rays produce by inducing nuclear reactions. Many shorter-lived radionuclides excluded from Table 1 such as 22Na (t1/2=2.6 yr) and 60Co (t1/2=5.27 yr) can also furnish valuable information, but can be measured only in meteorites that fell within the last few half-lives of those nuclides (see, e.g., Leya et al. (2001) and references therein). Table 1. Cosmogenic nuclides used for calculating exposure ages NuclideHalf-lifea (Myr) Radionuclides 14C0.005730 59Ni0.076 41Ca0.1034 81Kr0.229 36Cl0.301 26Al0.717 10Be1.51 53Mn3.74 129I15.7 Stable nuclides 3He 21Ne 38Ar 83Kr 126Xe a http://www2.bnl.gov/ton. CRE ages have implications for several interrelated questions. From how many different parent bodies do meteorites come? How well do meteorites represent the population of the asteroid belt? How many distinct collisions on each parent body have created the known meteorites of each type? How often do asteroids collide? How big and how energetic were the collisions that produced meteoroids? What factors control the CRE age of a meteorite and how do meteoroid orbits evolve through time? We will touch on these questions below as we examine the data.By 1975, the CRE ages of hundreds of meteorites had been estimated from noble gas measurements. Histograms of the CRE age distributions pointed to several important observations.(i) The CRE ages of meteorites increase in the order stones detection limits for cosmogenic nuclides and

Herzog, G. F.

2003-12-01

291

On emission lines in the cosmic gamma-ray background  

NASA Technical Reports Server (NTRS)

The composite spectrum of gamma-rays is calculated which results from the decay of Ni-56 to Co-56 to Fe-56 throughout the history of the universe. The results for several cosmological models are presented and compared with the Apollo 15 measurements at low resolution of the cosmic background. The radioactivity background is a significant fraction of the total, and several of its features may be detectable.-

Clayton, D. D.; Ward, R. A.

1975-01-01

292

Simulation of Cosmic Ray neutrinos Interactions in Water  

E-print Network

The program CORSIKA, usually used to simulate extensive cosmic ray air showers, has been adapted to a water medium in order to study the acoustic detection of ultra high energy neutrinos. Showers in water from incident protons and from neutrinos have been generated and their properties are described. The results obtained from CORSIKA are compared to those from other available simulation programs such as Geant4.

T. Sloan

2006-10-09

293

Hysteresis of primary cosmic rays associated with Forbush decreases  

Microsoft Academic Search

A variation of quasi-steady primary-cosmic-ray intensities during Forbush events is reported which was detected in data obtained by a neutron monitor, the OGO 1 and 3 ion chambers, and daily observations of upper-atmosphere intensities recorded with standardized Geiger-Mueller counters. A regression plot of the intensities of high- and low-rigidity primaries is found to exhibit hysteresis loops during Forbush decreases, indicating

R. S. Rajan

1976-01-01

294

Nuclear composition of solar cosmic rays  

NASA Technical Reports Server (NTRS)

Experimental observations of the elemental and isotopic composition of solar flare particles are discussed. Sources and characteristics of particle-emitting solar flare events are reviewed, and techniques for separating particle species are briefly described. Data are presented for the elemental composition of the solar atmosphere, and the possibility of determining the solar helium abundance from solar cosmic-ray observations is explored. The main experimental determinations of heavy element abundances at energies greater and less than 10 MeV/nucleon are summarized, and techniques for measuring the ionic charge composition of solar cosmic rays are outlined. Models explaining heavy element enhancements are described along with processes leading to gamma-ray emission during solar flare events. Observations of the rare isotopes of hydrogen and helium during solar flare events are noted, and a lower atmospheric limit is derived for nuclear reactions leading to positron decay. The possibility of investigating low-energy solar cosmic rays by measuring the relative abundances of different elements is evaluated.

Hovestadt, D.

1974-01-01

295

The Implications of a High Cosmic-Ray Ionization Rate in Diffuse Interstellar Clouds  

E-print Network

Diffuse interstellar clouds show large abundances of H_3^+ which can be maintained only by a high ionization rate of H_2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high cosmic-ray flux, and a large amount of energy residing in cosmic rays. In this paper we find that the standard propagated cosmic-ray spectrum predicts an ionization rate much lower than that inferred from H_3^+. Low-energy (~10 MeV) cosmic rays are the most efficient at ionizing hydrogen, but cannot be directly detected; consequently, an otherwise unobservable enhancement of the low-energy cosmic-ray flux offers a plausible explanation for the H_3^+ results. Beyond ionization, cosmic rays also interact with the interstellar medium by spalling atomic nuclei and exciting atomic nuclear states. These processes produce the light elements Li, Be, and B, as well as gamma-ray lines. To test the consequences of an enhanced low-energy cosmic-ray flux, we adopt two physically-motivated ...

Indriolo, Nick; McCall, Benjamin J

2009-01-01

296

Cosmic-ray knee and flux of secondaries from interactions of cosmic rays with dark matter  

E-print Network

We discuss possible implications of a large interaction cross section between cosmic rays and dark matter particles due to new physics at the TeV scale. In particular, in models with extra dimensions and a low fundamental scale of gravity the cross section grows very fast at transplanckian energies. We argue that the knee observed in the cosmic ray flux could be caused by such interactions. We show that this hypothesis implies a well defined flux of secondary gamma rays that seems consistent with MILAGRO observations.

Manuel Masip; Iacopo Mastromatteo

2009-04-06

297

Pointlike gamma ray sources as signatures of distant accelerators of ultrahigh energy cosmic rays.  

PubMed

We discuss the possibility of observing distant accelerators of ultrahigh energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photopion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be pointlike, steady, and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level. PMID:16384444

Gabici, Stefano; Aharonian, Felix A

2005-12-16

298

Quantum Black Holes from Cosmic Rays  

E-print Network

We investigate the possibility for cosmic ray experiments to discover non-thermal small black holes with masses in the TeV range. Such black holes would result due to the impact between ultra high energy cosmic rays or neutrinos with nuclei from the upper atmosphere and decay instantaneously. They could be produced copiously if the Planck scale is in the few TeV region. As their masses are close to the Planck scale, these holes would typically decay into two particles emitted back-to-back. Depending on the angles between the emitted particles with respect to the center of mass direction of motion, it is possible for the simultaneous showers to be measured by the detectors.

Xavier Calmet; Lauretiu Ioan Caramete; Octavian Micu

2012-11-19

299

Radiative Energy Loss by Galactic Cosmic Rays  

NASA Technical Reports Server (NTRS)

Interactions between galactic cosmic rays and matter are a primary focus of the NASA radiation problem. The electromagnetic forces involved are for the most part well documented. Building on previous research, this study investigated the relative importance of the weak forces that occur when a cosmic ray impinges on different types of materials. For the familiar electromagnetic case, it is known that energy lost in the form of radiation is more significant than that lost via contact collisions the rate at which the energy is lost is also well understood. Similar results were derived for the weak force case. It was found that radiation is also the dominant mode of energy loss in weak force interactions and that weak force effects are indeed relatively weak compared to electromagnetic effects.

Ahern, Sean C.; Norbury, John W.; Tripathi, R. K.

2002-01-01

300

Hydromagnetic waves and cosmic ray diffusion theory  

NASA Technical Reports Server (NTRS)

Pitch angle diffusion of cosmic rays in hydromagnetic wave fields is considered strictly within the quasilinear approximation. It is shown that the popular assumption of an isotropic power spectrum tensor of magnetic fluctuations requires in this case equal forms and magnitudes of Alfven and magnetosonic wave spectra - a situation which is generally unlikely. The relative contributions to the pitch angle diffusion coefficient from the cyclotron resonances and Landau resonance due to the different types of waves are evaluated for a typical situation in the solar wind. Since in this approximation also the Landau resonance does not lead to particle reflections a proper consideration of the nonlinear particle orbits is indeed necessary to overcome the well known difficulties of quasilinear scattering theory for cosmic rays near 90 degrees pitch angle.

Lee, M. A.; Voelk, H. J.

1975-01-01

301

Cosmic Ray Diffusion with Magnetic Focusing  

NASA Astrophysics Data System (ADS)

The cosmic ray transport along the mean magnetic field, controlled by fast pitch-angle scattering on magnetic fluctuations, has been long considered to be largely diffusive. On the other hand, long-scale variations in the mean field add a convective aspect to the transport due to the magnetic mirror force. The Chapman-Enskog approach is applied to the pitch-angle averaged spatial transport. Its convective part is shown to arise only due to this magnetic focusing effect. No “telegrapher” (mirror force independent) term emerges in any order of expansion, contrary to recent claims in the literature. Implications of the obtained transport equation for the spectra of cosmic rays accelerated in strong shocks and anomalous CR transport in Heliosphere are considered.

Malkov, Mikhail

302

The Pierre Auger Cosmic Ray Observatory  

E-print Network

The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above $10^{17}$ eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water-Cherenkov particle detector stations spread over 3000 km$^2$ overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5 km$^2$, 61 detector infill array. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000 km$^2$ sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Auger Observatory.

,

2015-01-01

303

Cosmic Ray Electron Science with GLAST  

NASA Technical Reports Server (NTRS)

Cosmic ray electrons at high energy carry information about their sources, their definition in local magnetic fields and their interactions with the photon fields through which they travel. The spectrum of the particles is affected by inverse Compton losses and synchrotron losses, the rates of which are proportional to the square of the particle's energy making the spectra very steep. However, GLAST will be able to make unique and very high statistics measurements of electrons from approx. 20 to approx. 700 GeV that will allow us to search for anisotropies in anival direction and spectral features associated with some dark matter candidates. Complementary information on electrons of still higher energy will be required to see effects of possible individual cosmic ray sources.

Ormes, J. F.; Moiseev, Alexander

2007-01-01

304

Cosmic Ray Electron Science with GLAST  

NASA Astrophysics Data System (ADS)

Cosmic ray electrons at high energy carry information about their sources, their diffusion in local magnetic fields and their interactions with the photon fields through which they travel. The spectrum of the particles is affected by inverse Compton losses and synchrotron losses, the rates of which are proportional to the square of the particle's energy making the spectra very steep. However, GLAST will be able to make unique and very high statistics measurements of electrons from ~20 to ~700 GeV that will allow us to search for anisotropies in arrival direction and spectral features associated with some dark matter candidates. Complementary information on electrons of still higher energy will be required to see effects of possible individual cosmic ray sources.

Ormes, J. F.; Moiseev, Alexander

2007-07-01

305

Galactic cosmic ray heavy primary secondary doses  

NASA Technical Reports Server (NTRS)

Results of a calculation which estimates the heavy primary secondary doses from cosmic ray interaction data are reported. The incident galactic cosmic ray heavy primary spectrum is represented as the sum of helium, nitrogen, magnesium, and iron components. The incident iron nuclei are allowed to fragment into lesser Z secondaries, which are assumed to travel in the same direction and start with the same energy per nucleon as the interacting primary. The total emergent particle energy spectra and dose are then presented for the galactic heavy primary spectrum incident on aluminum and tissue slabs. The importance of the fragmentation parameters assumed is also evaluated. The total dose from the heavy primaries and their secondaries is found to be reduced by only a factor of two in 20 g/sq cm of shielding.

Wilkinson, M. C.; Curtis, S. B.

1972-01-01

306

The Universe Viewed in Gamma-Rays 1 Galactic Diffuse Gamma-ray Spectrum from Cosmic-ray In-  

E-print Network

The Universe Viewed in Gamma-Rays 1 Galactic Diffuse Gamma-ray Spectrum from Cosmic-ray In- teractions with Gas Clouds Michiko OHISHI and Masaki MORI Institute for Cosmic Ray Research, University, Australia Abstract Gamma-ray spectra from cosmic-ray proton and electron interactions with gas clouds have

Mori, Masaki

307

Cosmic Ray induced Neutron and Gamma-Ray bursts in a Lead Pile  

SciTech Connect

The neutron background is created primarily by cosmic rays interactions. Of particular interest for SNM detection is an understanding of burst events that resemble fission chains. We have been studying the interaction of cosmic rays with a lead pile that is efficient at creating neutron bursts from cosmic ray interactions. The neutron burst size depends on the configuration of the lead. We have found that the largest bursts appear to have been created by primaries of energy over 100 GeV that have had a diffractive interaction with the atmosphere. The large events trigger muon coincidence paddles with very high efficiency, and the resulting interactions with the lead pile can create over 10, 000 neutrons in a burst.

Chapline, G; Hagmann, C; Kerr, P; Snyderman, N J; Wurtz, R

2007-05-08

308

Phenomenology of cosmic ray air showers  

E-print Network

The properties of cosmic rays with energies above 1PeV have to be deduced from the spacetime structure and particle content of the air showers which they initiate. In this review, a summary of the phenomenology of these giant air showers is presented. We describe the hadronic interaction models used to extrapolate results from collider data to ultra high energies, an also the main electromagnetic processes that govern the longitudinal shower evolution as well as the lateral spread of particles.

M. T. Dova

2005-05-30

309

Altitude variation of cosmic-ray neutrons  

Microsoft Academic Search

The altitude variation of the cosmic-ray neutron energy spectrum and the dose equivalent rate was measured at an average geomagnetic latitude of 24 degrees N by using the high-efficiency multi-sphere neutron spectrometer and neutron dose-equivalent counter developed by the authors. The data were obtained from a 2-h flight over Japan on 27 February 1985. The neutron energy spectra measured at

T. Nakamura; Y. Uwamino; T. Ohkubo; A. Hara

1987-01-01

310

Scientific Set of Instruments "Solar Cosmic Rays"  

NASA Astrophysics Data System (ADS)

A set of scientific instruments SCR (Solar Cosmic Rays) was developed by the scientists of SINP MSU and IEP SAS in order to study relations between the radiation conditions in the near-Earth space and solar activity. This set of instruments was installed on board the satellites CORONAS-I and CORONAS-F launched to the orbit on March 2, 1994, and July 30, 2001, respectively. Detailed description of the instruments is presented.

Kuznetsov, S. N.; Bogomolov, A. V.; Galkin, V. I.; Denisov, Yu. I.; Podorolsky, A. N.; Ryumin, S. P.; Kudela, K.; Rojko, J.

311

SUPERNOVA REMNANT KES 17: AN EFFICIENT COSMIC RAY ACCELERATOR INSIDE A MOLECULAR CLOUD  

SciTech Connect

The supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and ?-ray observations of this object, determining that efficient cosmic ray acceleration is required to explain its broadband non-thermal spectrum. These observations also suggest that Kes 17 is expanding inside a molecular cloud, though our determination of its age depends on whether thermal conduction or clump evaporation is primarily responsible for its center-filled thermal X-ray morphology. Evidence for efficient cosmic ray acceleration in Kes 17 supports recent theoretical work concluding that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhance cosmic ray production in supernova remnants. While additional observations are needed to confirm this interpretation, further study of Kes 17 is important for understanding how cosmic rays are accelerated in supernova remnants.

Gelfand, Joseph D. [NYU Abu Dhabi, P.O. Box 903, New York, NY 10276 (United States); Castro, Daniel [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue 37-241, Cambridge, MA 02139 (United States); Slane, Patrick O. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Temim, Tea [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hughes, John P. [Department of Physics and Astronomy Rutgers University 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rakowski, Cara, E-mail: jg168@cosmo.nyu.edu, E-mail: cara.rakowski@gmail.com [United States Patent and Trademark Office, 600 Dulany Street, Alexandria, VA (United States)

2013-11-10

312

Erich Regener - a forgotten cosmic ray pioneer  

NASA Astrophysics Data System (ADS)

In the 1930s the German physicist Erich Regener (1881-1955), did important work on the measurement of the rate production of ionisation in the atmosphere and deep under-water. He discovered, along with one of his students, Georg Pfotzer, the altitude at which the production of ionisation in the atmosphere reaches a maximum, often and misleadingly called the Pfotzer maximum. He was one of the first to estimate the energy density of cosmic rays, an estimate used by Baade and Zwicky to postulate that supernovae might be the source of cosmic rays. Yet Regener's name is little known largely because he was forced to take early retirement by the National Socialists in 1937 as his wife had Jewish ancestors. In this paper we review his work on cosmic rays and the subsequent influence that he had on the subject through his son, his son-in-law, his grandson and his students. He was nominated for the Nobel Prize in Physics by Schroedinger in 1938. He died in 1955 at the age of 73.

Carlson, Per; Watson, Alan

2013-04-01

313

Cosmic ray anisotropies near the heliopause  

NASA Astrophysics Data System (ADS)

Context. The Voyager 1 spacecraft became the first man-made probe to cross the heliopause into the local interstellar medium and measure the galactic environment, including charged particle intensities, in situ. Aims: We qualitatively explain the observed anisotropies of galactic and anomalous cosmic rays in the interstellar medium. Methods: A pitch-angle-dependent numerical model was constructed and applied to the study of both heliospheric (anomalous cosmic rays and termination shock particles) and galactic cosmic rays near the heliopause region. Results: In accordance with the observations, the model is able to reproduce the observed anisotropic nature of both particle populations. In the interstellar medium, the heliospheric particle distribution shows a peak at pitch angles near 90°, while for galactic particles, their distribution shows a deficiency at these pitch-angle values. Conclusions: The observed anisotropies are related to the pitch-angle dependence of the perpendicular diffusion coefficient, and if this dependence is chosen appropriately, the anisotropies observed by Voyager 1 can be explained naturally.

Strauss, R. D.; Fichtner, H.

2014-12-01

314

Cosmic Ray and Tev Gamma Ray Generation by Quasar Remnants  

NASA Technical Reports Server (NTRS)

Results from new broadband (radio to X-ray) high-resolution imaging studies of the dormant quasar remnant cores of nearby giant elliptical galaxies are now shown to permit the harboring of compact dynamos capable of generating the highest energy cosmic ray particles and associated curvature radiation of TeV photons. Confirmation would imply a global inflow of interstellar gas all the way to the accretion powered supermassive black hole at the center of the host galaxy.

Boldt, Elihu; Loewenstein, Michael; White, Nicholas E. (Technical Monitor)

2000-01-01

315

Cosmic-ray effects on diffuse gamma-ray measurements.  

NASA Technical Reports Server (NTRS)

Evaluation of calculations and experimental evidence from 600-MeV proton irradiation indicating that cosmic-ray-induced radioactivity in detectors used to measure the diffuse gamma-ray background produces a significant counting rate in the energy region around 1 MeV. It is concluded that these counts may be responsible for the observed flattening of the diffuse photon spectrum at this energy.

Fishman, G. J.

1972-01-01

316

Radio Cherenkov signals from the Moon: neutrinos and cosmic rays  

E-print Network

Neutrino production of radio Cherenkov signals in the Moon is the object of radio telescope observations. Depending on the energy range and detection parameters, the dominant contribution to the neutrino signal may come from interactions of the neutrino on the Moon facing the telescope, rather than neutrinos that have traversed a portion of the Moon. Using the approximate analytic expression of the effective lunar aperture from a recent paper by Gayley, Mutel and Jaeger, we evaluate the background from cosmic ray interactions in the lunar regolith. We also consider the modifications to the effective lunar aperture from generic non-standard model neutrino interactions. A background to neutrino signals are radio Cherenkov signals from cosmic ray interactions. For cosmogenic neutrino fluxes, neutrino signals will be difficult to observe because of low neutrino flux at the high energy end and large cosmic ray background in the lower energy range considered here. We show that lunar radio detection of neutrino interactions is best suited to constrain or measure neutrinos from astrophysical sources and probe non-standard neutrino-nucleon interactions such as microscopic black hole production.

Yu Seon Jeong; Mary Hall Reno; Ina Sarcevic

2011-08-11

317

Statistical properties of the time histories of cosmic gamma-ray bursts detected by the BATSE experiment of the Compton gamma-ray observatory  

NASA Technical Reports Server (NTRS)

The main scientific objectives of the project were: (1) Calculation of average time history for different subsets of BATSE gamma-ray bursts; (2) Comparison of averaged parameters and averaged time history for different Burst And Transient Source Experiments (BASTE) Gamma Ray Bursts (GRB's) sets; (3) Comparison of results obtained with BATSE data with those obtained with APEX experiment at PHOBOS mission; and (4) Use the results of (1)-(3) to compare current models of gamma-ray bursts sources.

Sagdeev, Roald

1995-01-01

318

A Constraint on Electromagnetic Acceleration of Highest Energy Cosmic Rays  

E-print Network

The energetics of electromagnetic acceleration of ultra-high-energy cosmic rays (UHECRs) is constrained both by confinement of a particle within an acceleration site and by radiative energy losses of the particle in the confining magnetic fields. We demonstrate that the detection of ~ 3 x 10^{20} eV events is inconsistent with the hypothesis that compact cosmic accelerators with high magnetic fields can be the sources of UHECRs. This rules out the most popular candidates, namely spinning neutron stars, active galactic nuclei (AGNs), and gamma-ray burst blast waves. Galaxy clusters and, perhaps, AGN radio lobes remain the only possible (although not very strong) candidates for UHECR acceleration sites. Our analysis places no limit on linear accelerators. With the data from the future Auger experiment one should be able to answer whether a conventional theory works or some new physics is required to explain the origin of UHECRs.

Mikhail V. Medvedev

2003-03-12

319

High-Energy Cosmic Rays from Gamma-Ray Bursts  

E-print Network

A model is proposed for the origin of cosmic rays (CRs) from ~10^14 eV to the highest energies, >10^20 eV. Gamma-Ray Bursts (GRBs) are assumed to inject CR protons and ions into the interstellar medium of star-forming galaxies--including the Milky Way--with a power law spectrum extending to a maximum energy ~10^20 eV. The CR spectrum near the knee is fit with CRs trapped in the Galactic halo that were accelerated and injected by an earlier Galactic GRB. These CRs diffuse in the disk and halo of the Galaxy due to gyroresonant pitch-angle scattering with MHD turbulence in the Galaxy's magnetic field. The preliminary (2001) KASCADE data through the knee of the CR spectrum are fit by a model with energy-dependent propagation of CR ions from a single Galactic GRB. Ultra-high energy CRs (UHECRs), with energies above the ankle are assumed to propagate rectilinearly with their spectrum modified by photo-pion, photo-pair, and expansion losses. We fit the measured UHECR spectrum assuming comoving luminosity densities of GRB sources consitent with possible star formation rate histories of the universe. For power-law CR proton injection p>2 this model implies that the nonthermal content in the GRB blast waves is hadronically dominated by a factor ~60-200. Calculations show that 100 TeV-100 PeV neutrinos could be detected several times per year from all GRBs in kilometer-scale neutrino detectors such as IceCube, for GRB blast-wave Doppler factors <~200. GLAST measurements of gamma-ray components and cutoffs will constrain the product of nonthermal baryon loading and radiative efficiency, limit the Doppler factor, and test this senario.

Stuart D. Wick; Charles D. Dermer; Armen Atoyan

2004-01-13

320

The intergalactic propagation of ultrahigh energy cosmic ray nuclei  

SciTech Connect

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.

2006-08-01

321

Cosmic Ray Positrons from Pulsars  

NASA Technical Reports Server (NTRS)

Pulsars are potential Galactic sources of positrons through pair cascades in their magnetospheres. There are, however, many uncertainties in establishing their contribution to the local primary positron flux. Among these are the local density of pulsars, the cascade pair multiplicities that determine the injection rate of positrons from the pulsar, the acceleration of the injected particles by the pulsar wind termination shock, their rate of escape from the pulsar wind nebula, and their propagation through the interstellar medium. I will discuss these issues in the context of what we are learning from the new Fermi pulsar detections and discoveries.

Harding, Alice K.

2010-01-01

322

PeV neutrinos from intergalactic interactions of cosmic rays emitted by active galactic nuclei.  

PubMed

The observed very high energy spectra of distant blazars are well described by secondary gamma rays produced in line-of-sight interactions of cosmic rays with background photons. In the absence of the cosmic-ray contribution, one would not expect to observe very hard spectra from distant sources, but the cosmic ray interactions generate very high energy gamma rays relatively close to the observer, and they are not attenuated significantly. The same interactions of cosmic rays are expected to produce a flux of neutrinos with energies peaked around 1 PeV. We show that the diffuse isotropic neutrino background from many distant sources can be consistent with the neutrino events recently detected by the IceCube experiment. We also find that the flux from any individual nearby source is insufficient to account for these events. The narrow spectrum around 1 PeV implies that some active galactic nuclei can accelerate protons to EeV energies. PMID:23931348

Kalashev, Oleg E; Kusenko, Alexander; Essey, Warren

2013-07-26

323

Cosmic Ray Helium Intensities over the Solar Cycle from ACE  

NASA Technical Reports Server (NTRS)

Observations of cosmic-ray helium energy spectra provide important constraints on cosmic ray origin and propagation. However, helium intensities measured at Earth are affected by solar modulation, especially below several GeV/nucleon. Observations of helium intensities over a solar cycle are important for understanding how solar modulation affects galactic cosmic ray intensities and for separating the contributions of anomalous and galactic cosmic rays. The Cosmic Ray Isotope Spectrometer (CRIS) on ACE has been measuring cosmic ray isotopes, including helium, since 1997 with high statistical precision. We present helium elemental intensities between approx. 10 to approx. 100 MeV/nucleon from the Solar Isotope Spectrometer (SIS) and CRIS observations over a solar cycle and compare these results with the observations from other satellite and balloon-borne instruments, and with GCR transport and solar modulation models.

DeNolfo, G. A.; Yanasak, N. E.; Binns, W. R.; Cohen, C. M. S.; Cummings, A. C.; Davis, A. J.; George, J. S.; Hink. P. L.; Israel, M. H.; Lave, K.; Leske, R. A.; Mewaldt, R. A.; Moskalenko, I. V.; Ogliore, R.; Stone, E. C.; Von Rosenvinge, T. T.; Wiedenback, M. E.

2007-01-01

324

Cosmic ray constraints on singlino-like dark matter candidates  

E-print Network

Recent results from direct detection experiments (Dama, CoGeNT), though subject to debate, seem to point toward a low mass (few GeV) dark matter (DM) particle. However, low mass DM candidates are not easily achieved in the MSSM nor NMSSM. As shown by some authors, singlet extensions of the MSSM can lead to GeV mass neutralinos and satisfy relic abundance constraints. We propose here to extract indirect detection constraints on these models in a generic way from cosmic-ray anti-proton measurements (PAMELA data)

Timur Delahaye; David Cerdeño; Julien Lavalle

2011-06-10

325

Testing Fundamental Physics with High-Energy Cosmic Rays  

E-print Network

Cosmic rays may provide opportunities for probing fundamental physics. For example, ultra-high-energy cosmic rays might originate from the decays of metastable heavy particles, and astrophysical gamma rays can be used to test models of quantum gravity. Both scenarios offer ways to avoid the GZK cut-off.

John Ellis

2000-10-24

326

WMAP, Planck, cosmic rays and unconventional cosmologies  

E-print Network

The claim by Gurzadyan et al. that the cosmological sky is a weakly random one where "the random perturbation is a minor component of mostly regular signal" has given rise to a series of useful exchanges. The possibility that the Cosmic Microwave Background radiation (CMB) data present trends in this direction would have strong implications for unconventional cosmologies. Similarly, data on ultra-high energy cosmic rays may contain signatures from new Physics generated beyond the Planck scale. It therefore seems legitimate, from a phenomenological point of view, to consider pre-Big Bang cosmologies as well as patterns where standard particles would not be the ultimate constituents of matter and the presently admitted principles of Physics would not necessarily be the fundamental ones. We discuss here prospects for some noncyclic, nonstandard cosmologies.

Luis Gonzalez-Mestres

2011-10-27

327

Ultra High Energy Cosmic Rays: present status and future prospects  

E-print Network

Reasons for the current interest in cosmic rays above 10^19 eV are described. The latest results on the energy spectrum, arrival direction distribution and mass composition of cosmic rays are reviewed, including data that were reported after the meeting in Blois in June 2001. The enigma set by the existence of ultra high-energy cosmic rays remains. Ideas proposed to explain it are discussed and progress with the construction of the Pierre Auger Observatory is outlined.

A. A. Watson

2001-12-20

328

The isotopic composition of cosmic-ray calcium  

NASA Technical Reports Server (NTRS)

We find that the relative abundance of cosmic ray calcium isotopes in the cosmic-ray source are very similar to those found in solar-system material, in spite of the fact that different types of stars are thought to be responsible for producing these two isotopes. This observation is consistent with the view that cosmic rays are derived from a mixed sample of interstellar matter.

Wiedenbeck, M. E.; George, J. S.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; Israel, M. H.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; Rosenvinge, T. T. von

2001-01-01

329

Superheavy dark matter and ultrahigh energy cosmic rays  

E-print Network

The phase of inflationary expansion in the early universe produces superheavy relics in a mass window between 10^{12} GeV and 10^{14} GeV. Decay or annihilation of these superheavy relics can explain the observed ultrahigh energy cosmic rays beyond the Greisen-Zatsepin-Kuzmin cutoff. We emphasize that the pattern of cosmic ray arrival directions with energies beyond 20 EeV will decide between the different proposals for the origin of ultrahigh energy cosmic rays.

R. Dick; K. M. Hopp; K. E. Wunderle

2005-08-01

330

Cosmic Ray Impact on Extrasolar Earth-Like Planets in Close-in Habitable Zones  

Microsoft Academic Search

Because of their different origins, cosmic rays can be subdivided into galactic cosmic rays and solar\\/stellar cosmic rays. The flux of cosmic rays to planetary surfaces is mainly determined by two planetary parameters: the atmospheric density and the strength of the internal magnetic moment. If a planet exhibits an extended magnetosphere, its surface will be protected from high-energy cosmic ray

J.-M. Grießmeier; A. Stadelmann; U. Motschmann; N. K. Belisheva; H. Lammer; H. K. Biernat

2005-01-01

331

Acoustic instability driven by cosmic-ray streaming  

NASA Technical Reports Server (NTRS)

We study the linear stability of compressional waves in a medium through which cosmic rays stream at the Alfven speed due to strong coupling with Alfven waves. Acoustic waves can be driven unstable by the cosmic-ray drift, provided that the streaming speed is sufficiently large compared to the thermal sound speed. Two effects can cause instability: (1) the heating of the thermal gas due to the damping of Alfven waves driven unstable by cosmic-ray streaming; and (2) phase shifts in the cosmic-ray pressure perturbation caused by the combination of cosmic-ray streaming and diffusion. The instability does not depend on the magnitude of the background cosmic-ray pressure gradient, and occurs whether or not cosmic-ray diffusion is important relative to streaming. When the cosmic-ray pressure is small compared to the gas pressure, or cosmic-ray diffusion is strong, the instability manifests itself as a weak overstability of slow magnetosonic waves. Larger cosmic-ray pressure gives rise to new hybrid modes, which can be strongly unstable in the limits of both weak and strong cosmic-ray diffusion and in the presence of thermal conduction. Parts of our analysis parallel earlier work by McKenzie & Webb (which were brought to our attention after this paper was accepted for publication), but our treatment of diffusive effects, thermal conduction, and nonlinearities represent significant extensions. Although the linear growth rate of instability is independent of the background cosmic-ray pressure gradient, the onset of nonlinear eff ects does depend on absolute value of DEL (vector differential operator) P(sub c). At the onset of nonlinearity the fractional amplitude of cosmic-ray pressure perturbations is delta P(sub C)/P(sub C) approximately (kL) (exp -1) much less than 1, where k is the wavenumber and L is the pressure scale height of the unperturbed cosmic rays. We speculate that the instability may lead to a mode of cosmic-ray transport in which plateaus of uniform cosmic-ray pressure are separated by either laminar or turbulent jumps in which the thermal gas is subject to intense heating.

Begelman, Mitchell C.; Zweibel, Ellen G.

1994-01-01

332

The contribution of cosmic rays to global warming  

E-print Network

A search has been made for a contribution of the changing cosmic ray intensity to the global warming observed in the last century. The cosmic ray intensity shows a strong 11 year cycle due to solar modulation and the overall rate has decreased since 1900. These changes in cosmic ray intensity are compared to those of the mean global surface temperature to attempt to quantify any link between the two. It is shown that, if such a link exists, the changing cosmic ray intensity contributes less than 8% to the increase in the mean global surface temperature observed since 1900.

Sloan, Terry

2011-01-01

333

Acoustic instability driven by cosmic-ray streaming  

NASA Astrophysics Data System (ADS)

We study the linear stability of compressional waves in a medium through which cosmic rays stream at the Alfven speed due to strong coupling with Alfven waves. Acoustic waves can be driven unstable by the cosmic-ray drift, provided that the streaming speed is sufficiently large compared to the thermal sound speed. Two effects can cause instability: (1) the heating of the thermal gas due to the damping of Alfven waves driven unstable by cosmic-ray streaming; and (2) phase shifts in the cosmic-ray pressure perturbation caused by the combination of cosmic-ray streaming and diffusion. The instability does not depend on the magnitude of the background cosmic-ray pressure gradient, and occurs whether or not cosmic-ray diffusion is important relative to streaming. When the cosmic-ray pressure is small compared to the gas pressure, or cosmic-ray diffusion is strong, the instability manifests itself as a weak overstability of slow magnetosonic waves. Larger cosmic-ray pressure gives rise to new hybrid modes, which can be strongly unstable in the limits of both weak and strong cosmic-ray diffusion and in the presence of thermal conduction. Parts of our analysis parallel earlier work by McKenzie & Webb (which were brought to our attention after this paper was accepted for publication), but our treatment of diffusive effects, thermal conduction, and nonlinearities represent significant extensions. Although the linear growth rate of instability is independent of the background cosmic-ray pressure gradient, the onset of nonlinear eff ects does depend on absolute value of DEL (vector differential operator) Pc. At the onset of nonlinearity the fractional amplitude of cosmic-ray pressure perturbations is delta PC/PC approximately (kL) -1 much less than 1, where k is the wavenumber and L is the pressure scale height of the unperturbed cosmic rays. We speculate that the instability may lead to a mode of cosmic-ray transport in which plateaus of uniform cosmic-ray pressure are separated by either laminar or turbulent jumps in which the thermal gas is subject to intense heating.

Begelman, Mitchell C.; Zweibel, Ellen G.

1994-08-01

334

Cosmic-ray record in solar system matter  

SciTech Connect

The energetic nuclei in cosmic rays interact with meteoroids, the moon, planets, and other solar system matter. The nucleides and heavy nuclei tracks produced by the cosmic-ray particles in these targets contain a wealth of information about the history of the objects and temporal ans spatial variations in the particle fluxes. Most lunar samples and many meteorites ahve complex histories of cosmic-ray exposure from erosion, gardening, fragmentation, orbital changes, and other processes. There appear to be variations in the past fluxes of solar particles, and possibly also galactic cosmic rays, on time scales of 10/sup 4/ to 10/sup 7/ years.

Reedy, R.C. (Los Alamos National Lab., NM); Arnold, J.R.; Lal, D.

1983-01-14

335

Gamma-rays, cosmic rays, and galactic structure  

NASA Technical Reports Server (NTRS)

The relation of SAS-2 observations of galactic gamma-rays to the large scale distribution of cosmic rays and interstellar gas in the galaxy is reviewed. Starting with a discussion of production rates, the case for pion decay being the predominant production mechanism in the galactic disk above 100 MeV is reestablished, and it is also pointed out that Compton gamma-rays can be a significant source near l = 0. The concepts of four distinct galactic regions are defined, viz. the nebulodisk, ectodisk, radiodisk and exodisk. Bremsstrahlung and pion decay gamma-rays are associated with the first two (primarily the first) regions, and Compton gamma-rays and synchrotron radiation are associated with the latter two regions. On a large scale, the cosmic rays, interstellar gas (primarily H2 clouds in the inner galaxy) and gamma-ray emissivity all peak between 5 and 6 kpc from the galactic center. This correlation is related to correlation with other population I phenomena and is discussed in terms of the density wave concept of galactic structure.

Stecker, F. W.

1976-01-01

336

Lunar surface cosmic ray experiment S-152, Apollo 16  

NASA Technical Reports Server (NTRS)

This investigation was directed at determining the energy spectra and abundances of low energy heavy cosmic rays (0.03 E or = 150 MeV/nucleon). The cosmic rays were detected using plastic and glass particle track detectors. Particles emitted during the 17 April 1972 solar flare dominated the spectra for energies below about 70 MeV/nucleon. Two conclusions emerge from the low energy data: (1) The differential energy spectra for solar particles vary rapidly for energies as low as 0.05 MeV/nucleon for iron-group nuclei. (2) The abundance ratio of heavy elements changes with energy at low energies; heavy elements are enhanced relative to higher elements increasingly as the energy decreases. Galactic particle fluxes recorded within the spacecraft are in agreement with those predicted taking into account solar modulation and spacecraft shielding. The composition of the nuclei at energies above 70 MeV/nucleon imply that these particles originate outside the solar system and hence are galactic cosmic rays.

Fleischer, R. L.; Hart, H. R., Jr.; Carter, M.; Comostock, G. M.; Renshaw, A.; Woods, R. T.

1973-01-01

337

Radiation Hazard from Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

Space radiation is a major hazard to astronauts in long-duration human space explosion. Astronauts are exposed to an enormous amount of radiation during their missions away from the Earth in outer space. Deep space is a rich environment of protons, gamma rays and cosmic rays. A healthy 40 years old man staying on Earth away from large doses of radiation stands a 20% chance of dying from cancer. If the same person travels into a 3- year Mars mission, the added risk should increase by 19%. This indicates that there is 39% chance of having cancer after he comes back to Earth. Female astronaut chances to get cancer is even almost double the above percentage. The greatest threat to astronauts en route to the red planet is galactic cosmic rays (GCR). GCRs penetrate through the skin of spaceships and people like tiny firearm bullets, breaking the strands of DNA molecules, damaging genes, and killing cells. Understanding the nature of the GCRs, their effect on biological cells, and their interactions with different shielding materials is the key point to shield against them in long space missions. In this paper we will present a model to evaluate the biological effects of GCRs and suggestion different ways to shield against them.

Farahat, Ashraf

2006-03-01

338

High Energy Cosmic Rays from Local GRBs  

E-print Network

We have developed a model that explains cosmic rays with energies E between \\~0.3 PeV and the energy of the second knee at E_2 ~ 3*10^{17} eV as originating from a recent Galactic gamma-ray burst (GRB) that occurred ~1 Myr ago within 1 kpc from Earth. Relativistic shocks from GRBs are assumed to inject power-law distributions of cosmic rays (CRs) to the highest energies. Diffusive propagation of CRs from the local GRB explains the CR spectrum near and above the first knee at E_1 ~ 3*10^{15} eV. The first and the second knees are explained as being directly connected with the injection of plasma turbulence in the interstellar medium on a ~1 pc and ~100 pc scales, respectively. Transition to CRs from extragalactic GRBs occurs at E > E_2. The origin of the ankle in the CR spectrum at E ~ 4*10^{18} eV is due to photopair energy losses of UHECRs on cosmological timescales, as also suggested by Berezinsky and collaborators. Any significant excess flux of extremely high energy CRs deviating from the exponential cutoff behavior at E> E_{GZK} = 6*10^{19} eV would imply a significant contribution due to recent GRB activity on timescales t < 10^8 yrs from local extragalactic sources within ~10 Mpc.

A. Atoyan; C. D. Dermer

2005-08-23

339

High-Energy Cosmic Ray Event Data from the Pierre Auger Cosmic Ray Observatory  

DOE Data Explorer

The Pierre Auger Cosmic Ray Observatory in Mendoza, Argentina is the result of an international collaboration funded by 15 countries and many different organizations. Its mission is to capture high-energy cosmic ray events or air showers for research into their origin and nature. The Pierre Auger Collaboration agreed to make 1% of its data available to the public. The Public Event Explorer is a search tool that allows users to browse or search for and display figures and data plots of events collected since 2004. The repository is updated daily, and, as of June, 2014, makes more than 35,000 events publicly available. The energy of a cosmic ray is measured in Exa electron volts or EeV. These event displays can be browsed in order of their energy level from 0.1 to 41.1 EeV. Each event has an individual identification number.

The event displays provide station data, cosmic ray incoming direction, various energy measurements, plots, vector-based images, and an ASCII data file.

340

Gravity, Cosmic Rays and the LHC  

E-print Network

The high energy proton beams expected when the Large Hadron Collider (LHC) comes online should provide a pass/fail test for a gravity-related explanation of ultrahigh energy cosmic rays. The model predicts that particles have two kinds energies, equal for null gravitational potentials and, in the potential at the Earth, differing significantly above one TeV. If correct, a 7 TeV trajectory energy proton at the LHC would deliver a 23.5 TeV particle state energy in a collision.

Richard Shurtleff

2008-01-20

341

The interplanetary transport of solar cosmic rays  

NASA Technical Reports Server (NTRS)

Numerical solutions are presented for the propagation of solar cosmic rays in interplanetary space, including the effects of pitch-angle scattering and adiabatic focusing. The intensity-time profiles can be well fitted by a simple radial spatial diffusion equation with scattering mean-free path lambda(fit). The radial mean-free path so obtained is significantly larger than the true scattering mean-free path for low-rigidity particles due to both adiabatic focusing and the inapplicability of the diffusive approximation early in the event. The well-known discrepancy between lambda(fit) and the theoretical predictions may be resolved by these calculations.

Gombosi, T. I.; Owens, A. J.

1980-01-01

342

High energy cosmic ray iron spectrum experiment  

NASA Technical Reports Server (NTRS)

An instrument containing a gas Cerenkov counter and an iron ionization spectrometer was constructed in order to measure the cosmic-ray iron spectrum to 300 GeV/nucleon. Trajectories of particles were determined by entopistic or position-determining scintillator systems. The geometric factors with and without the gas Cerenkov counter were 0.3 and 0.6 sq m-ster, respectively. The instrument was successfully flown in June 1976 without the spectrometer and in October 1976 with the spectrometer from Palestine, Texas. The June flight yielded 14.5 h of data; the October flight, 25 h.

Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Schmidt, W. K. H.; Simon, M.; Spiegelhauer, H.

1978-01-01

343

Galactic origin of cosmic rays I  

SciTech Connect

The theoretical basis for the supernova envelope shock origin of cosmic rays is reviewed. The theoretical explanation of the SN Type I light curve requires the ejection of a relativistic mass fraction. The criterion of the adiabatic decelleration by Alfven wave trapping neither applies in theory, when ..beta.. > 1, or practice, the Starfish high altitude nuclear explosion experiment. Arguments of delayed acceleration due to K-capture are not applicable to SN ejecta because a period of prompt recombination exists before subsequent stripping in propagation.

Colgate, S.A.

1981-01-01

344

Fermi Pulsars and the Cosmic Ray Knee  

E-print Network

Nuclei, if lifted into the radiation zone of a weak axisymmetric pulsar, are accelerated to quasi-monoenergetic spectrum, with more than half of the nuclear luminosity emitted nearly monoenergetically, at the energy E approximately = 4Ze(L/c)^(1/2), where L is the spin-down power. With a number of (not obviously wrong) assumptions, this turns Fermi (-like) weak pulsars into prominent accelerators at energies near the cosmic ray knee. The main uncertainty is purely theoretical: one needs to understand if nuclei are major positive charge carries in some weak pulsar magnetospheres.

Gruzinov, Andrei

2013-01-01

345

Cosmic ray origins in supernova blast waves  

NASA Astrophysics Data System (ADS)

We extend the self-similar solution derived by Chevalier for a Sedov blast wave accelerating cosmic rays (CR) to show that the Galactic CR population can be divided into (A) CR with energies above ˜200 GeV released upstream during CR acceleration by supernova remnants (SNR), (B) CR advected into the interior of the SNR during expansion and then released from the SNR at the end of its life to provide the Galactic CR component below ˜200 GeV. The intersection between the two populations may correspond to a measured change in the Galactic CR spectral index at this energy.

Bell, A. R.

2015-03-01

346

Nonextensive thermal sources of cosmic rays?  

E-print Network

The energy spectrum of cosmic rays (CR) exhibits power-like behavior with a very characteristic "knee" structure. We consider a possibility that such a spectrum could be generated by some specific nonstatistical temperature fluctuations in the source of CR with the "knee" structure reflecting an abrupt change of the pattern of such fluctuations. This would result in a generalized nonextensive statistical model for the production of CR. The possible physical mechanisms leading to these effects are discussed together with the resulting chemical composition of the CR, which follows the experimentally observed abundance of nuclei.

Grzegorz Wilk; Zbigniew Wlodarczyk

2009-11-07

347

The source abundances of galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The galactic cosmic ray source abundances have been determined from two complete datasets, one at low and the other at high energy. For both exponential and truncated exponential pathlength distributions (PLD), the two sets of source abundances show significant differences for the primary elements, i.e., the Fe/O ratio. An energy dependent PLD reduces but does not eliminate the discrepancy, and this may indicate an energy dependence in the source composition. New source abundances for Na, P, Cl, Ca, and Mn are derived.

Dwyer, R. D.; Garcia-Munoz, M.; Guzik, T. G.; Meyer, P.; Simpson, J. A.; Wefel, J. P.

1982-01-01

348

The Cosmic-Ray Isotope Spectrometer for the Advanced Composition Explorer  

Microsoft Academic Search

The Cosmic-Ray Isotope Spectrometer is designed to cover the highest decade of the Advanced Composition Explorer's energy\\u000a interval, from ?50 to ?500 MeV nucl?1, with isotopic resolution for elements from Z?2 to Z?30. The nuclei detected in this\\u000a energy interval are predominantly cosmic rays originating in our Galaxy. This sample of galactic matter can be used to investigate\\u000a the nucleosynthesis

E. C. Stone; C. M. S. Cohen; W. R. Cook; A. C. Cummings; B. Gauld; B. Kecman; R. A. Leske; R. A. Mewaldt; M. R. Thayer; B. L. Dougherty; R. L. Grumm; B. D. Milliken; R. G. Radocinski; M. E. Wiedenbeck; E. R. Christian; S. Shuman; H. Trexel; T. T. von Rosenvinge; W. R. Binns; D. J. Crary; P. Dowkontt; J. Epstein; P. L. Hink; J. Klarmann; M. Lijowski; M. A. Olevitch

1998-01-01

349

Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors  

SciTech Connect

We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100 times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

Yamamoto, Kazuhiro; Hayakawa, Hideaki; Okada, Atsushi; Uchiyama, Takashi; Miyoki, Shinji; Ohashi, Masatake; Kuroda, Kazuaki; Kanda, Nobuyuki; Tatsumi, Daisuke; Tsunesada, Yoshiki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Department of Physics, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, Osaka 558-8585 (Japan); National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2008-07-15

350

Cosmic Ray streaming from SNRs and gamma ray emission from nearby molecular clouds  

E-print Network

High-energy gamma ray emission has been detected recently from supernovae remnants (SNRs) and their surroundings. The existence of molecular clouds near some of the SNRs suggests that the gamma rays originate predominantly from p-p interactions with cosmic rays accelerated at a closeby SNR shock wave. Here we investigate the acceleration of cosmic rays and the gamma ray production in the cloud self-consistently by taking into account the interactions of the streaming instability and the background turbulence both at the shock front and in the ensuing propagation to the clouds. We focus on the later evolution of SNRs, when the conventional treatment of the streaming instability is valid but the magnetic field is enhanced due to either Bell's current instability and/or due to the dynamo generation of magnetic field in the precursor region. We calculate the time dependence of the maximum energy of the accelerated particles. This result is then used to determine the diffusive flux of the runaway particles escaping the shock region, from which we obtain the gamma spectrum consistent with observations. Finally, we check the self-consistency of our results by comparing the required level of diffusion with the level of the streaming instability attainable in the presence of turbulence damping. The energy range of cosmic rays subject to the streaming instability is able to produce the observed energy spectrum of gamma rays.

Huirong Yan; A. Lazarian; R. Schlickeiser

2011-11-10

351

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Solar modulation of cosmic rays since 1936: Neutron monitors and balloon-borne data  

E-print Network

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Solar modulation of cosmic rays since 1936 used to parameterize the energy spectrum of galactic cosmic rays, for the period from July 1936 through of flux of cosmic ray ionizing radiation in the stratosphere performed by the Lebedev Physical Institute

Usoskin, Ilya G.

352

Probing cosmic-ray acceleration and propagation with H3+ observations  

NASA Astrophysics Data System (ADS)

As cosmic rays traverse the interstellar medium (ISM) they interact with the ambient gas in various ways. These include ionization of atoms and molecules, spallation of nuclei, excitation of nuclear states, and production of pions among others. All of these interactions produce potential observables which may be used to trace the flux of cosmic rays. One such observable is the molecular ion H3+-produced via the ionization of an H2 molecule and its subsequent collision with another H2-which can be identified by absorption lines in the 3.5-4 ?m spectral region. We have detected H3+ in several Galactic diffuse cloud sight lines and used the derived column densities to infer ?2, the cosmic-ray ionization rate of H2. Ionization rates determined in this way vary from about 7×10-17 s-1 to about 8×10-16 s-1, and suggest the possibility of discrete sources producing high local fluxes of low-energy cosmic rays. Theoretical calculations of the ionization rate from postulated cosmic-ray spectra also support this possibility. Our recent observations of H3+ near the supernova remnant IC 443 (a likely site of cosmic-ray acceleration) point to even higher ionization rates, on the order of 10-15 s-1. Together, all of these results can further our understanding of the cosmic-ray spectrum both near the acceleration source and in the general Galactic ISM.

Indriolo, Nick; Fields, Brian D.; McCall, Benjamin J.

2015-01-01

353

Multipoint cosmic ray data as a useful tool for the testing magnetospheric magnetic field models  

NASA Astrophysics Data System (ADS)

We analyze feasibility and limitations of multipoint cosmic ray data registered by worldwide net of cosmic ray neutron monitors to be a tool for validating magnetospheric MF models. Our approach is based on the fact, that variations of cosmic rays are related to changes in geomagnetic cutoff rigidities. We calculated changes in cutoff rigidities during geomagnetic storms for the number of neutron monitor stations located at different latitudes and characterized by different cutoff rigidities in the main geomagnetic field. We have compared the cutoff rigidity changes obtained by the trajectory tracing method in the model magnetospheric magnetic field with those obtained on the base of experimental cosmic ray neutron monitor data. The models were Tsyganenko 1989 and its upgraded version Tsyganenko 1996. Our aim was to study if the "cosmic ray tool" is able to detect this upgrading. The obtained results have shown that cosmic ray experimental data can be successfully used for estimation of dynamic aspects of magnetospheric magnetic field models at mid latitudes. The use of cosmic ray data for evaluation of amplitude accuracy of the model magnetic field requires further research.

Tyasto, Marta; Ptitsyna, Natalia; Villoresi, Giorgio; Danilova, Olga; Sdobnov, Valery; Dvornikov, Valery

354

Cosmic-ray physics with the milagro gamma-ray observatory  

SciTech Connect

The Milagro gamma-ray observatory is a water Cherenkov detector with an energy response between 100 GeV and 100 TeV. While the major scientific goals of Milagro were to detect and study cosmic sources of TeV gamma rays, Milagro has made measurements important to furthering our understanding of the cosmic radiation that pervades our Galaxy. Milagro has made the first measurement of the Galactic diffuse emission in the TeV energy band. In the Cygnus Region we measure a flux {approx}2.7 times that predicted by GALPROP. Milagro has also made measurements of the anisotropy of the arrival directions of the local cosmic radiation. On large scales the measurements made by Milagro agree with those previously reported by the Tibet AS{gamma} array. However, we have also discovered a time dependence to this anisotropy, perhaps due to solar modulation. On smaller scales, {approx}10 degrees, we have detected two regions of excess. These excesses have a spectrum that is inconsistent with the local cosmic-ray spectrum.

Sinnis, Gus [Los Alamos National Laboratory

2008-01-01

355

Intergalactic Propagation of UHE Cosmic Rays  

E-print Network

We discuss the intergalactic propagation of ultra-high-energy cosmic rays (UHECRs) with energies E \\geq 10^{18.5} eV. We consider the propagation of UHECRs under the influence of the energy-dependent deflection by a weak random magnetic field in the intergalactic medium and energy losses by photo-pion and pair production. We calculate arrival spectra taking full account of the kinematics of photo-pion production and the Poisson statistics of the photo-pion interaction rate. We give estimates for the deflection of UHECRs from the line of sight to the source, time delays with respect to photons from the same source, arrival spectra and source statistics. These estimates are confirmed by numerical simulations of the propagation in energy evolution of UHECRs. These simulations demonstrate that the often-used continuous approximation in the treatment of energy losses due to photo-pion production on the cosmic microwave background (CMWB) cannot be justified for UHECRs. We discuss the implications of these results for the observed flux of particles above the Greisen-Zatsepin-Kuz'min cut-off in two of the scenarios that have been proposed for the production of these particles: continuous production in the large shock waves associated with powerful radio galaxies, or possibly large-scale structure formation, and the impulsive production at relativistic blast waves associated with cosmological gamma-ray bursts.

Abraham Achterberg; Yves A. Gallant; Colin A. Norman; Donald B. Melrose

1999-07-05

356

Nineteenth International Cosmic Ray Conference. HE Sessions, Volume 7  

NASA Technical Reports Server (NTRS)

Papers submitted for presentation at the 19th International Cosmic ray Conference are compiled. This volume contains papers which address various aspects of extensive air showers (EAS) produced by energetic particles and gamma rays.

Jones, F. C. (compiler)

1985-01-01

357

On-board detection and removal of cosmic ray and solar energetic particle signatures for the Solar Orbiter-METIS coronagraph  

NASA Astrophysics Data System (ADS)

METIS is part of the science payload of Solar Orbiter. It is a coronagraph designed to obtain images of the outer solar corona both in the visible 580-640 nm band and in the UV, in a narrow band centered around the hydrogen Lyman-? line. We describe the main features of the procedures to remove signatures due to cosmic rays (CRs) and to solar energetic particles (SEPs) comparing them with alternatives in other contexts and in other solar coronagraphic missions. Our analysis starts from a realistic assessment of the radiation environment where the instrument is expected to operate, which is characteristic of the interplanetary space of the inner solar system, but quite unusual for most solar missions.

Andretta, V.; Bemporad, A.; Focardi, M.; Grimani, C.; Landini, F.; Pancrazzi, M.; Sasso, C.; Spadaro, D.; Straus, T.; Uslenghi, M. C.; Antonucci, E.; Fineschi, S.; Naletto, G.; Nicolini, G.; Nicolosi, P.; Romoli, M.

2014-07-01

358

Balloon test project: Cosmic Ray Antimatter Calorimeter (CRAC)  

NASA Technical Reports Server (NTRS)

Cosmic ray observations from balloon flights are discussed. The cosmic ray antimatter calorimeter (CRAC) experiment attempts to measure the flux of antimatter in the 200-600 Mev/m energy range and the isotopes of light elements between 600 and 1,000 Mev/m.

Christy, J. C.; Dhenain, G.; Goret, P.; Jorand, J.; Masse, P.; Mestreau, P.; Petrou, N.; Robin, A.

1984-01-01

359

Direct Measurements, Acceleration and Propagation of Cosmic Rays  

Microsoft Academic Search

This paper summarizes highlights of the OG1 session of the 30th International Cosmic Ray Conference, held in Merida (Yucatan, Mexico). The subsessions (OG1.1, OG1.2, OG1.3, OG1.4 and OG1.5) summarized here were mainly devoted to direct measurements, acceleration and propagation of cosmic rays.

Pasquale Blasi

2008-01-01

360

THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH  

SciTech Connect

We employ three-dimensional state-of-the-art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic-ray transport to investigate the cosmic-ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic-ray spectrum is to changes in the sunspot placement and magnetic field strength, the large-scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic-ray flux than is the case today. The cosmic-ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic-ray flux at 1 AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variations in the dipole field component. The wind ram pressure affects the cosmic-ray flux through its influence on the size of the heliosphere via the pressure balance with the ambient interstellar medium. Variations in the interstellar medium pressure experienced by the solar system in orbit through the Galaxy could lead to order of magnitude changes in the cosmic-ray flux at Earth on timescales of a few million years.

Cohen, O.; Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)

2012-11-20

361

Investigation of Muon Bundles in Horizontal Cosmic Ray Flux  

Microsoft Academic Search

A new large area coordinate detector DECOR is deployed around water Cherenkov calorimeter NEVOD and is intended for studies of various cosmic ray components at the Earth's surface. On the basis of data accumulated during experimental runs 2002 2003, the first results on cosmic ray muon bundles are obtained. Preliminary data on zenith angle dependence of the ratio of muon

I. I. Yashin; N. S. Barbashina; A. Bogdanov; D. V. Chernov; V. V. Kindin; R. P. Kokoulin; K. G. Kompanients; G. Mannocchi; E. O. Nikilaeva; A. A. Petrukhin; O. Saavedra; V. V. Shutenko; G. Trinchero; E. E. Yanson; O. S. Zolina

2003-01-01

362

Ninteenth International Cosmic Ray Conference. SH Sessions, Volume 4  

NASA Technical Reports Server (NTRS)

Papers submitted for presentation at the 19th International Cosmic Ray Conference are compiled. This volume covers solar and heliospheric phenomena, specifically, particle acceleration; cosmic ray compsotion, spectra, and anisotropy; propagation of solar and interplanetary energetic particles; solar-cycle modulation; and propagation of galactic particles in the heliosphere.

Jones, F. C. (compiler)

1985-01-01

363

Ninteenth International Cosmic Ray Conference. OG Sessions, Volume 2  

NASA Technical Reports Server (NTRS)

Contributed papers addressing cosmic ray origin and galactic phenomena are compiled. Topic areas include the composition, spectra, and anisotropy of cosmic ray nuclei with energies and 1 TeV, isotopes, antiprotons and related subjects, and electrons, positrons, and measurements of synchrotron radiation.

Jones, F. C. (compiler)

1985-01-01

364

The Cosmic-Ray Equator and the Earth's Magnetic Field  

Microsoft Academic Search

The positions of the cosmic-ray intensity minimum off the west coast of Africa and in the Indian Ocean, respectively, have been determined from measurements obtained with a shipboard neutron monitor during two voyages between Scandinavia and Australia. The cosmic-ray equator is in accordance with the prediction based upon calculations of modified cutoff rigidities at the first location, but differs by

Martin A. Pomerantz; Vasant R. Potnis; Arne E. Sandström

1960-01-01

365

THE COMPOSITION OF ULTRA HIGH ENERGY COSMIC RAYS THROUGH HYBRID  

E-print Network

THE COMPOSITION OF ULTRA HIGH ENERGY COSMIC RAYS THROUGH HYBRID ANALYSIS AT TELESCOPE ARRAY fulfillment of the requirements for the degree of Doctor of Philosophy in Physics Department of Physics Kieda Physics and Astronomy #12;ABSTRACT The chemical composition of cosmic rays is critically important

366

Early developments: Particle physics aspects of cosmic rays  

NASA Astrophysics Data System (ADS)

Cosmic rays is the birthplace of elementary particle physics. The 1936 Nobel prize was shared between Victor Hess and Carl Anderson. Anderson discovered the positron in a cloud chamber. The positron was predicted by Dirac several years earlier. In subsequent cloud chamber investigations Anderson and Neddermeyer saw the muon, which for some time was considered to be a candidate for the Yukawa particle responsible for nuclear binding. Measurements with nuclear emulsions by Lattes, Powell, Occhialini and Muirhead clarified the situation by the discovery of the charged pions in cosmic rays. The cloud chamber continued to be a powerful instrument in cosmic ray studies. Rochester and Butler found V's, which turned out to be shortlived neutral kaons decaying into a pair of charged pions. Also ?'s, ?'s, and ?'s were found in cosmic rays. But after that accelerators and storage rings took over. The unexpected renaissance of cosmic rays started with the search for solar neutrinos and the observation of the supernova 1987A. Cosmic ray neutrino results were best explained by the assumption of neutrino oscillations opening a view beyond the standard model of elementary particles. After 100 years of cosmic ray research we are again at the beginning of a new era, and cosmic rays may contribute to solve the many open questions, like dark matter and dark energy, by providing energies well beyond those of accelerators.

Grupen, Claus

2014-01-01

367

WORLD-WIDE COSMIC-RAY VARIATIONS, 1937–1952  

Microsoft Academic Search

Annual means from continuous registration of cosmic-ray ionizktion at four stations from 1937 to 1952 show a variation of nearly four per cent, which is similar at all stations and which is negatively correlated with sunspot numbers. This variation in cosmic-ray intensity is quite similar for the annual means of all days, international magnetic quiet days, and international magnetic disturbed

Scott E. Forbush

1954-01-01

368

Direct Measurements, Acceleration and Propagation of Cosmic Rays  

E-print Network

This paper summarizes highlights of the OG1 session of the 30th International Cosmic Ray Conference, held in Merida (Yucatan, Mexico). The subsessions (OG1.1, OG1.2, OG1.3, OG1.4 and OG1.5) summarized here were mainly devoted to direct measurements, acceleration and propagation of cosmic rays.

Pasquale Blasi

2008-01-29

369

The effect of sea level cosmic rays on electronic devices  

Microsoft Academic Search

The evaluation of the effects of cosmic rays on computer memories and its application to typical memory devices will be discussed. Conclusions indicate that cosmic ray nucleons and muons could have a significant effect on the next generation of computer memory circuitry. Error rates increase rapidly with altitude, offering the potential of accelerated testing to make electronic equipment less sensitive

J. Ziegler; W. Lanford

1980-01-01

370

The acceleration of cosmic rays by shock waves  

Microsoft Academic Search

The direct transfer of energy to cosmic rays from supersonic motions of the background medium via shock waves, by means of an efficient first order Fermi mechanism, is considered. The acceleration of cosmic rays by shock waves is most effective in the dilute and hot, 1,000,000-K component of the interstellar medium. There is no limit to the energy that can

W. I. Axford

1981-01-01

371

On the heliolatitude distribution of galactic cosmic rays  

Microsoft Academic Search

An analysis of the annual and semiannual variation of the galactic cosmic ray intensity has been performed for the period 1953-1979 by using the data from the Climax and Dourbes neutron monitors. The analysis, based on a method for searching periodicities and recurrences in the cosmic ray intensity, has confirmed the existence of such variations and their phase changes associated

E. Antonucci; M. R. Attolini; S. Cecchini; M. Galli

1985-01-01

372

A new transition radiation detector for cosmic ray nuclei  

NASA Technical Reports Server (NTRS)

Test measurements on materials for transition radiation detectors at a low Lorentz factor are reported. The materials will be based on board Spacelab-2 for determining the composition and energy spectra of nuclear cosmic rays in the 1 TeV/nucleon range. The transition radiation detectors consist of a sandwich of radiator-photon detector combinations. The radiators emit X-rays and are composed of polyolefin fibers used with Xe filled multiwired proportional chamber (MWPC) detectors capable of detecting particle Lorentz factors of several hundred. The sizing of the detectors is outlined, noting the requirement of a thickness which provides a maximum ratio of transition radiation to total signal in the chambers. The fiber radiator-MWPC responses were tested at Fermilab and in an electron cyclotron. An increase in transition radiation detection was found as a square power law of Z, and the use of six radiator-MWPC on board the Spacelab-2 is outlined.

Lheureux, J.; Meyer, P.; Muller, D.; Swordy, S.

1981-01-01

373

The cosmic ray luminosity of the nearby active galactic nuclei  

E-print Network

The pointing directions of extensive air showers observed at the Pierre Auger Observatory were fitted within 3.1 degree with positions of the nearby active galactic nuclei from the Veron-Cetty and P. Veron catalog. The cosmic ray luminosity of the active galactic nuclei which happened to be a source of the particular cosmic ray event constitutes a fraction ~0.0001 of the optical one if only cosmic ray particles with energies above 60 EeV are produced. If produced cosmic ray particles have a spectrum dE/E^3 up to ~100 GeV then the cosmic ray luminosity would be much higher than the optical one of the active galactic nuclei.

L. G. Dedenko; D. A. Podgrudkov; T. M. Roganova; G. F. Fedorova

2008-04-29

374

Cosmic ray spectrum, composition, and anisotropy measured with IceCube  

NASA Astrophysics Data System (ADS)

Analysis of cosmic ray surface data collected with the IceTop array of Cherenkov detectors at the South Pole provides an accurate measurement of the cosmic ray spectrum and its features in the “knee” region up to energies of about 1 EeV. IceTop is part of the IceCube Observatory that includes a deep-ice cubic kilometer detector that registers signals of penetrating muons and other particles. Surface and in-ice signals detected in coincidence provide clear insights into the nuclear composition of cosmic rays. IceCube already measured an increase of the average primary mass as a function of energy. We present preliminary results on both IceTop-only and coincident events analysis. Furthermore, we review the recent measurement of the cosmic ray anisotropy with IceCube.

Tamburro, Alessio

2014-04-01

375

Terrestrial Effects of High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

On geological timescales, the Earth is likely to be exposed to an increased flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Increased ionization could lead to changes in atmospheric chemistry, resulting in ozone depletion. This could increase the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit can could possibly enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose. The muon flux dominates radiation dose from cosmic rays causing DNA damage and increase in the mutation rates, which can have serious biological implications for terrestrial and sub-terrestrial life. This radiation dose is an important constraint on the habitability of a planet. Using CORSIKA, we perform massive computer simulations and construct lookup tables from 10 GeV - 1 PeV primaries (1 PeV - 0.1 ZeV in progress), which can be used to quantify these effects. These tables are freely available to the community and can be used for other studies, not necessarily relevant to Astrobiology. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. This could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

Atri, Dimitra

2011-01-01

376

Detection of polarization in the cosmic microwave background using DASI  

E-print Network

Detection of polarization in the cosmic microwave background using DASI J. M. Kovac*, E. M. Leitch differences in the cosmic microwave background (CMB) radiation on angular scales of the order of a degree

Cai, Long

377

Studies of the cosmic ray spectrum and large scale anisotropies with the KASCADE-Grande experiment  

NASA Astrophysics Data System (ADS)

KASCADE-Grande is an air shower observatory devoted to the detection of cosmic rays in the 1016 - 1018eV energy range. For each event the arrival direction, the total number of charged particles (Nch) and the total number of muons (N?), at detection level (i.e. 110 m a.s.l.), are measured. The detection of these observarbles, with high accuracy, allows the study of the primary spectrum, chemical composition and large scale anisotropies, that are the relevant informations to investigate the astrophysics of cosmic rays in this energy range. These studies are of main importance to deeply investigate the change of slope of the primary spectrum detected at ~ 4 × 1015 eV, also known as the knee, and to search for the transition from galactic to extra-galactic cosmic rays.

Chiavassa, A.; Apel, W. D.; Arteaga-Velázquez, J. C.; Bekk, K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Cantoni, E.; Cossavella, F.; Curcio, C.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Engler, J.; Fuchs, B.; Fuhrmann, D.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Huber, D.; Huege, T.; Kampert, K.-H.; Kang, D.; Klages, H. O.; Link, K.; ?uczak, P.; Ludwig, M.; Mathes, H. J.; Mayer, H. J.; Melissas, M.; Milke, J.; Mitrica, B.; Morello, C.; Oehlschläger, J.; Ostapchenko, S.; Palmieri, N.; Petcu, M.; Pierog, T.; Rebel, H.; Roth, M.; Schieler, H.; Schoo, S.; Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Weindl, A.; Wochele, J.; Zabierowski, J.

2014-08-01

378

Transition from galactic to extragalactic cosmic rays  

NASA Astrophysics Data System (ADS)

The study of the transition between galactic and extragalactic cosmic rays can shed more light on the end of the galactic cosmic rays spectrum and the beginning of the extragalactic one. Three models of transition are discussed: ankle, dip and mixed composition models. All these models describe the transition as an intersection of a steep galactic component with a flat extragalactic one. Severe bounds on these models are provided by the Standard Model of galactic cosmic rays according to which the maximum acceleration energy for Iron nuclei is of the order of EFemax?1×1017eV. In the ankle model the transition is assumed at the ankle, a flat feature in the all particle spectrum which observationally starts at energy Ea˜(3-4)×1018eV. This model needs a new high energy galactic component with maximum energy about two orders of magnitude above that of the Standard Model. The origin of such component is discussed. As observations are concerned there are two signatures of the transition: change of energy spectra and mass composition. In all models a heavy galactic component is changed at the transition to a lighter or proton component. As a result the ankle model predicts a galactic Iron component at E<5×1018eV, while both HiRes and Auger data show that at (2-5)×1018eV primaries are protons, or at least light nuclei. In the dip model the transition occurs at the second knee observed at energy (4-7)×1017eV and is characterized by a sharp change of mass composition from galactic Iron to extragalactic protons. The ankle in this model appears automatically as a part of the e+e- pair-production dip. The mixed composition model describes transition at E˜3×1018eV with mass composition changing from the galactic Iron to extragalactic mixed composition of different nuclei. In most mixed composition models the spectrum is proton-dominated and it better fits HiRes than Auger data. The latter show a steadily heavier mass composition with increasing energy, and we discuss the models which explain it.

Aloisio, R.; Berezinsky, V.; Gazizov, A.

2012-12-01

379

PREFACE: 23rd European Cosmic Ray Symposium (and 32nd Russian Cosmic Ray Conference)  

NASA Astrophysics Data System (ADS)

The 23rd European Cosmic Ray Symposium (ECRS) took place in Moscow at the Lomonosov Moscow State University (3-7 July 2012), and was excellently organized by the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University, with the help of the Russian Academy of Sciences and the Council on the Complex Problem of Cosmic Rays of the Russian Academy of Sciences. The first symposia were held in 1968 in Lodz, Poland (high energy, extensive air showers and astrophysical aspects) and in Bern (solar and heliospheric phenomena) and the two 'strands' joined together in 1976 with the meeting in Leeds. Since then the symposia, which have been very successful, have covered all the major topics with some emphasis on European collaborations and on meeting the demands of young scientists. Initially, a driving force was the need to overcome the divisions caused by the 'Cold War' but the symposia continued even when that threat ceased and they have shown no sign of having outlived their usefulness. 2012 has been an important year in the history of cosmic ray studies, in that it marked the centenary of the discovery of enigmatic particles in the perilous balloon ascents of Victor Hess. A number of conferences have taken place in Western Europe during the year, but this one took place in Moscow as a tribute to the successful efforts of many former USSR and other Eastern European scientists in discovering the secrets of the subject, often under very difficult conditions. The symposium covers a wide range of scientific issues divided into the following topics: PCR-IPrimary cosmic rays I (E < 1015 eV) PCR-IIPrimary cosmic rays II (E > 1015 eV) MNCosmic ray muons and neutrinos GAGeV and TeV gamma astronomy SHEnergetic particles in the heliosphere (solar and anomalous CRs and GCR modulation) GEOCosmic rays and geophysics (energetic particles in the atmosphere and magnetosphere of the Earth) On a personal note, as I step down as co-founder and chairman of the International Advisory Committee, I should like to thank those very many colleagues and friends with whom I have had the pleasure of working over the past 45 years. These thanks are extended to the present organizers. The organizers are very grateful to the Russian Foundation of Basic Research and to the Dynasty non-profit foundation for financial support. Arnold Wolfendale

Erlykin, A. D.; Kokoulin, R. P.; Lidvansky, A. S.; Meroshnichenko, L. I.; Panasyuk, M. I.; Panov, A. D.; Wolfendale, A. W.

2013-02-01

380

Cosmic ray simulator: A versatile apparatus for quantitative studies on the interaction of cosmic rays with frozen solids by on line and in sift  

E-print Network

Cosmic ray simulator: A versatile apparatus for quantitative studies on the interaction of cosmic) The cosmic ray simulator consists of a 50 L'cylindrical stainless steel chamber. A rotable cold finger milled spectrometer (FTIR) in an absorption-reflection mode at 62.5". For the first time, a cosmic ray simulator

Kaiser, Ralf I.

381

Tevatron QCD for Cosmic-Rays  

SciTech Connect

The two multi-purpose experiments D0 and CDF are operated at the Tevatron collider, where proton anti-proton collisions take place at a centre of mass energy of 1.96 TeV in Run II. In the kinematic plane of Q{sup 2}-scale and (anti-)proton momentum fraction x, Tevatron jet measurements cover a wide range, with phase space regions in common and beyond the HERA ep-collider reach. The kinematic limit of the Auger experiment is given by a centre of mass energy of 100 TeV. Cosmic rays cover a large region of the kinematic phase space at low momenta x, corresponding to forward proton/diffractive physics and also at low scales, corresponding to the hadronization scale and the underlying event. Therefore of particular interest are exclusive and diffractive measurements as well as underlying event, double parton scattering and minimum bias measurements. The kinematic limit of the Tevatron corresponds to the PeV energy region below the knee of the differential cosmic particle flux energy distribution. The data discussed here are in general corrected for detector effects, such as efficiency and acceptance. Therefore they can be used directly for testing and improving existing event generators and any future calculations/models. Comparisons take place at the hadronic final state (particle level).

Sonnenschein, Lars; /RWTH Aachen U.

2010-12-01

382

Cosmic ray neon, Wolf-Rayet stars, and the superbubble origin of galactic cosmic rays  

E-print Network

The abundances of neon isotopes in the galactic cosmic rays (GCRs) are reported using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). We compare our ACE-CRIS data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (WR) models. The three largest deviations of GCR isotope ratios from solar-system ratios predicted by these models are indeed present in the GCRs. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with WR models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.

W. R. Binns; M. E. Wiedenbeck; M. Arnould; A. C. Cummings; J. S. George; S. Goriely; M. H. Israel; R. A. Leske; R. A. Mewaldt; G. Meynet; L. M. Scott; E. C. Stone; T. T. von Rosenvinge

2005-08-18

383

Evidence for the Superbubble Origin of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

Measurements of the isotopic and elemental abundances of galactic cosmic rays from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the NASA-ACE spacecraft, and elemental abundances from the balloon-borne Trans-Iron Galactic Element Recorder (TIGER) provide strong evidence that a large fraction of galactic cosmic rays originate and are accelerated in associations of massive stars (OB associations) and their associated superbubbles. Neon and iron isotopic abundances point to a superbubble origin in which the galactic cosmic rays (GCRs) come from material that is roughly a 20%-80% mix of OB association material and ordinary interstellar medium material (ISM). This assumption that GCRs come from such a mix instead of ordinary ISM results in greatly improved ordering of volatile and refractory GCR elemental abundances when plotted versus atomic mass. This strengthens the OB association-superbubble connection with cosmic ray origin. More recently, the LAT instrument aboard the Fermi spacecraft has identified distributed emission of gamma-rays from a "cocoon" identified with the Cygnus-X superbubble, indicating the acceleration of cosmic rays in the superbubble. These measurements and the implications for the OB-association/superbubble origin of galactic cosmic rays will be discussed. Principal funding for this research was from NASA under grants NNG05WC04G and NAG5-12929.

Binns, W.

2012-12-01

384

Low-energy cosmic ray protons from nuclear interactions of cosmic rays with the interstellar medium.  

NASA Technical Reports Server (NTRS)

The intensity of low-energy (less than 100 MeV) protons from nuclear interactions of higher-energy (above 100 MeV) cosmic rays with the interstellar medium is calculated. The resultant intensity in the 10- to 100-MeV range is larger by a factor of 3-5 than the observed proton intensity near earth. The calculated intensity from nuclear interactions constitutes a lower limit on the actual proton intensity in interstellar space.

Wang, H. T.

1973-01-01

385

Cosmic ray drift, shock wave acceleration, and the anomalous component of cosmic rays  

Microsoft Academic Search

A model of the anomalous component of the quiet-time cosmic ray flux is presented in which ex--interstellar neutral particles are accelerated continuously in the polar regions of the solar-wind termination shock and then drift into the equatorial regions of the inner heliosphere. The observed solar-cycle variations, radial gradient, and apparent latitude gradient of the anomalous component are a natural consequence

M. E. Pesses; J. R. Jokipii; D. Eichler

1981-01-01

386

30TH INTERNATIONAL COSMIC RAY CONFERENCE Gamma-ray albedo of the moon  

E-print Network

30TH INTERNATIONAL COSMIC RAY CONFERENCE Gamma-ray albedo of the moon I. V. MOSKALENKO1,2 , T. A@stanford.edu Abstract: We use the GEANT4 Monte Carlo framework to calculate the -ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees

Moskalenko, Igor V.

387

Cosmic Ray Propagation in Galactic Turbulence  

NASA Astrophysics Data System (ADS)

We revisit propagation of galactic cosmic rays (CRs) in light of recent advances in CR diffusion theory in realistic interstellar turbulence. We use a tested model of turbulence in which it has been shown that fast modes dominate scattering of CRs. As a result, propagation becomes inhomogeneous and environment dependent. By adopting the formalism of the nonlinear theory developed by Yan & Lazarian, we calculate the diffusion of CRs self-consistently from first principles. We assume a two-phase model for the Galaxy to account for different damping mechanisms of the fast modes, and we find that the energy dependence of the diffusion coefficient is mainly affected by medium properties. We show that it gives a correct framework to interpret some of the recent CR puzzles.

Evoli, Carmelo; Yan, Huirong

2014-02-01

388

TIROS-N Cosmic Ray study  

NASA Technical Reports Server (NTRS)

An experimental and analytical study was performed on the impact of galactic cosmic rays on the TIROS-N satellite memory in orbit. Comparisons were made of systems equipped with the Harris HMI-6508 1 x 1024 CMOS/bulk RAM and the RCA CDP-1821 1 x 1024 bit CMOS/SOS RAM. Based upon the experimental results, estimated bit error rates were determined. These were at least 8.0 bit errors/day for a 300 kilobit memory with the HMI-6508 and .014 bit errors/day with the CDF-1821. It was also estimated that the HMI-6508 latchup rate in orbit is at least two orders of magnitude less than the bit error rates; the CDP-1821 will not latchup.

Blandford, J. T., Jr.; Pickel, J. C.

1980-01-01

389

Structures in the cosmic ray energy spectra  

E-print Network

All the components of cosmic rays have 'structure' in their energy spectra at some level, ie deviations from a simple power law, and their examination is relevant to the origin of the particles. Emphasis, here, is placed on the large-scale structures in the spectra of nuclei (the 'knee' at about 3 PeV), that of electrons and positrons (a shallow 'upturn' at about 100 GeV) and the positron to electron plus positron ratio (an upturn starting at about 5 GeV). Fine structure is defined as deviations from the smooth spectra which already allow for the large-scale structure. Search for the fine structure has been performed in the precise data on positron to electron plus positron ratio measured by the AMS-02 experiment. Although no fine structure is indicated, it could in fact be present at the few percent level.

Erlykin, Anatoly

2013-01-01

390

Neutrino yield from Galactic cosmic rays  

NASA Astrophysics Data System (ADS)

We calculate the neutrino yield from collisions of cosmic ray (CR) nuclei with gas using the event generator QGSJET-II. We present first the general characteristics and numerical results for the neutrino yield assuming power-law fluxes for the primary CR nuclei. Then we use three parametrizations for the Galactic CR flux to derive the neutrino yield for energies around and above the knee. The shape and the normalization of the resulting neutrino flux above ˜1014 eV depends on the composition of the Galactic CR flux employed, but is generally dominated by its proton component. The spectral shape and magnitude of the neutrino flux suggest that the IceCube excess is not connected to interactions of Galactic sea CRs.

Kachelrieß, M.; Ostapchenko, S.

2014-10-01

391

Estimates of cellular mutagenesis from cosmic rays  

NASA Technical Reports Server (NTRS)

A parametric track structure model is used to estimate the cross section as a function of particle velocity and charge for mutations at the hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus in human fibroblast cell cultures. Experiments that report the fraction of mutations per surviving cell for human lung and skin fibroblast cells indicate small differences in the mutation cross section for these two cell lines when differences in inactivation rates between these cell lines are considered. Using models of cosmic ray transport, the mutation rate at the HGPRT locus is estimated for cell cultures in space flight and rates of about 2 to 10 x 10(exp -6) per year are found for typical spacecraft shielding. A discussion of how model assumptions may alter the predictions is also presented.

Cucinotta, Francis A.; Wilson, John W.

1994-01-01

392

Galactic Cosmic Rays in the Outer Heliosphere  

NASA Technical Reports Server (NTRS)

We report a next generation model of galactic cosmic ray (GCR) transport in the three dimensional heliosphere. Our model is based on an accurate three-dimensional representation of the heliospheric interface. This representation is obtained by taking into account the interaction between partially ionized, magnetized plasma flows of the solar wind and the local interstellar medium. Our model reveals that after entering the heliosphere GCRs are stored in the heliosheath for several years. The preferred GCR entry locations are near the nose of the heliopause and at high latitudes. Low-energy (hundreds of MeV) galactic ions observed in the heliosheath have spent, on average, a longer time in the solar wind than those observed in the inner heliosphere, which would explain their cooled-off spectra at these energies. We also discuss radial gradients in the heliosheath and the implications for future Voyager observations

Florinski, V.; Washimi, H.; Pogorelov, N. V.; Adams, J. H.

2010-01-01

393

Cosmic Rays: The Second Knee and Beyond  

E-print Network

We conduct a review of experimental results on Ultra-High Energy Cosmic Rays (UHECR's) including measurements of the features of the spectrum, the composition of the primary particle flux and the search for anisotropy in event arrival direction. We find that while there is a general consensus on the features in the spectrum -- the Second Knee, the Ankle, and (to a lesser extent) the GZK Cutoff -- there is little consensus on the composition of the primaries that accompany these features. This lack of consensus on the composition makes interpretation of the agreed upon features problematic. There is also little direct evidence about potential sources of UHECRs, as early reports of arrival direction anisotropies have not been confirmed in independent measurements.

Douglas R Bergman; John W. Belz

2007-04-27

394

The `excess' of primary cosmic ray electrons  

E-print Network

With the accurate cosmic ray (CR) electron and positron spectra (denoted as $\\Phi_{\\rm e^{-}}$ and $\\Phi_{\\rm e^{+}}$, respectively) measured by AMS-02 collaboration, the difference between the electron and positron fluxes (i.e., $\\Delta \\Phi=\\Phi_{\\rm e^{-}}-\\Phi_{\\rm e^{+}}$), dominated by the propagated primary electrons, can be reliably inferred. In the standard model, the spectrum of propagated primary CR electrons at energies $\\geq 30$ GeV softens with the increase of energy. The absence of any evidence for such a continuous spectral softening in $\\Delta \\Phi$ strongly suggests a significant `excess' of primary CR electrons and at energies of $100-400$ GeV the identified excess component has a flux comparable to that of the observed positron excess. Middle-age but `nearby' supernova remnants (e.g., Monogem and Geminga) are favored sources for such an excess.

Xiang Li; Zhao-Qiang Shen; Bo-Qiang Lu; Tie-Kuang Dong; Yi-Zhong Fan; Lei Feng; Si-Ming Liu; Jin Chang

2014-12-04

395

Analytic solutions of ultrahigh energy cosmic ray nuclei revisited  

NASA Astrophysics Data System (ADS)

The chemical composition of ultrahigh energy cosmic rays is a key question in particle astrophysics. The measured composition, inferred from the elongation rates of cosmic ray showers, looks in general very different from the initial source composition: resonant photo-disintegration in the cosmic radiation background proceeds rapidly at the highest energies and the initial composition quickly becomes lighter during propagation. For a statistical analysis of continuously improving cosmic ray data it is desirable to know the secondary spectra as precisely as possible. Here, we discuss exact analytic solutions of the evolution equation of ultrahigh energy cosmic ray nuclei. We introduce a diagrammatic formalism that leads to a systematic analytic expansion of the exact solution in terms of second order effects of the propagation. We show how the first order corrections of this expansion can improve the predictions of secondary spectra in a semianalytical treatment.

Ahlers, Markus; Taylor, Andrew M.

2010-12-01

396

Transition from galactic to extragalactic cosmic rays  

E-print Network

The transition from galactic to extragalactic cosmic rays is discussed. One of critical indications for transition is given by the Standard Model of Galactic cosmic rays, according to which the maximum energy of acceleration for iron nuclei is of order of $E_{\\rm Fe}^{\\rm max} \\approx 1\\times 10^{17}$ eV. At $E > E_{\\rm Fe}^{\\rm max}$ the spectrum is predicted to be very steep and thus the Standard Model favours the transition at energy not much higher than $E_{\\rm Fe}^{\\rm max}$. As observations are concerned there are two signatures of transition: change of energy spectra and elongation rate (depth of shower maximum in the atmosphere $X_{\\rm max}$ as function of energy). Three models of transition are discussed: dip-based model, mixed composition model and ankle model. In the latter model the transition occurs at the observed spectral feature, ankle, which starts at $E_a \\approx 1\\times 10^{19}$ eV and is characterised by change of mass compostion from galactic iron to extragalactic protons. In the dip model the transition occures at the second knee observed at energy $(4 -8)\\times 10^{17}$ eV and is characterised by change of mass composition from galactic iron to extragalactic protons. The mixed composition model describes transition at $E \\sim 3\\times 10^{18}$ eV with mass composition changing from galactic iron to extragactic mixed composition of different nuclei. These models are confronted with observational data on spectra and elongation rates from different experiments, including Auger.

V. Berezinsky

2007-10-20

397

Galactic Cosmic Ray Composition Beyond the Fe-Group and the Origin of Cosmic Rays  

NASA Astrophysics Data System (ADS)

We review the present status of cosmic ray composition measurements in the middle third of the periodic table using data from three sources. The Advanced Composition Explorer (ACE) has now completed more than 16 years in orbit and its Cosmic Ray Isotope Spectrometer (CRIS) has now collected more than 200 nuclei with Z = 31-40, somewhat more than were recorded in two earlier balloon flights by the Trans-Iron Galactic Element Recorder (TIGER). Both of these data sets provide individual element resolution and they agree well. Combining the two data sets we find a mass-dependent ordering of both refractory and volatile elements when compared with massive star outflow and supernova ejecta mixed with normal interstellar material. Refractory elements are preferentially accelerated by a factor of ~4. These data support an OB-association origin of galactic cosmic rays. Finally, we take a first look at new composition data from Super-TIGER, which has achieved both improved charge resolution and collecting power with a single record-breaking 55-day balloon flight.

Mewaldt, Richard

398

Cosmic ray anisotropy as signature for the transition from galactic to extragalactic cosmic rays  

SciTech Connect

We constrain the energy at which the transition from Galactic to extragalactic cosmic rays occurs by computing the anisotropy at Earth of cosmic rays emitted by Galactic sources. Since the diffusion approximation starts to loose its validity for E/Z?>10{sup 16?17} eV, we propagate individual cosmic rays using Galactic magnetic field models and taking into account both their regular and turbulent components. The turbulent field is generated on a nested grid which allows spatial resolution down to fractions of a parsec. Assuming sufficiently frequent Galactic CR sources, the dipole amplitude computed for a mostly light or intermediate primary composition exceeds the dipole bounds measured by the Auger collaboration around E ? 10{sup 18} eV. Therefore, a transition at the ankle or above would require a heavy composition or a rather extreme Galactic magnetic field with strength ?>10 ?G. Moreover, the fast rising proton contribution suggested by KASCADE-Grande data between 10{sup 17} eV and 10{sup 18} eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E?>10{sup 18} eV, the transition energy can be close to the ankle, if Galactic CRs are produced by sufficiently frequent transients as e.g. magnetars.

Giacinti, G.; Kachelrieß, M. [Institutt for fysikk, NTNU, Trondheim (Norway); Semikoz, D.V. [AstroParticle and Cosmology (APC), Paris (France); Sigl, G. [II. Institut für Theoretische Physik, Universität Hamburg, Hamburg (Germany)

2012-07-01

399

PREFACE: Cosmic Ray Anisotropy Workshop 2013 (CRA2013)  

NASA Astrophysics Data System (ADS)

In the search for the origin of cosmic rays in our galaxy, various observations are combined as pieces of a complex puzzle to account for the variability of the galactic sources and their local environments, as well as of the properties of the interstellar medium in which cosmic particles propagate. In this puzzle, multi-wavelength observations aim to pinpoint the properties of cosmic-ray sources, based on electromagnetic and neutrino emissions associated with hadronic acceleration processes. The detailed study of the energy spectrum and composition of cosmic rays on Earth, on the other hand, aims to probe the combined and interwoven effects of injection, by acceleration processes, and propagation in the interstellar medium. The observation of arrival directions of cosmic rays on Earth, in addition, potentially provides valuable information on the distribution of the closest and more recent active galactic sources as well as on the properties of the local interstellar magnetic field. The quasi-isotropic distribution of galactic cosmic rays tells the global story of their journey from their sources. The turbulent magnetized galactic medium sufficiently scrambles the arrival directions of cosmic rays on Earth so that their main injection direction is concealed. On the other hand, the observations of a small but significant energy-dependent anisotropy are starting to provide clues on how cosmic rays propagate throughout the local interstellar medium. Anisotropy observations have been used to study diffusion properties of GeV cosmic rays inside the termination shock of the heliosphere and their dependencies on solar cycles. At TeV energy, cosmic rays are sensitive to larger-scale magnetic structures, such as the turbulent boundary between the heliosphere and the local interstellar medium or its elongated tail. At higher energy, it is expected that the interstellar magnetic field within the particle mean free path has major contributions to their arrival directions on Earth. In this workshop, we addressed the potential use of high-energy cosmic-ray anisotropy observations as a probe into the properties of particle transport in astrophysical magnetized plasmas, such as the heliosphere and the local interstellar medium. Along with experts from the fields of astronomy, astrophysics, plasma physics, heliospheric physics and interstellar medium, we discussed how each field can contribute to the understanding of cosmic-ray propagation in our local interstellar magnetic field. This will represent another piece in the search for cosmic-ray sources in the galaxy.

2014-08-01

400

Cosmic Ray Signatures from Decaying Gravitino Dark Matter  

E-print Network

We study the charged cosmic rays arising from the slow decay of gravitino dark matter within supersymmetric scenarios with trilinear R-parity violation. It is shown that operators of the LLE type can very well account for the recent anomalies in cosmic ray electron and positron data reported by PAMELA, ATIC and Fermi LAT, without violating any other bounds. This scenario will soon be tested by the Fermi LAT data on diffuse gamma ray emission.

N. -E. Bomark; S. Lola; P. Osland; A. R. Raklev

2009-11-18

401

Searching for New Physics with Ultrahigh Energy Cosmic Rays  

NASA Technical Reports Server (NTRS)

Ultrahigh energy cosmic rays that produce giant extensive showers of charged particles and photons when they interact in the Earth's atmosphere provide a unique tool to search for new physics. Of particular interest is the possibility of detecting a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10 (exp -35) m. We discuss here the possible signature of Lorentz invariance violation on the spectrum of ultrahigh energy cosmic rays as compared with present observations of giant air showers. We also discuss the possibilities of using more sensitive detection techniques to improve searches for Lorentz invariance violation in the future. Using the latest data from the Pierre Auger Observatory, we derive a best fit to the LIV parameter of 3 .0 + 1.5 - 3:0 x 10 (exp -23) ,corresponding to an upper limit of 4.5 x 10-23 at a proton Lorentz factor of approximately 2 x 10(exp 11) . This result has fundamental implications for quantum gravity models.

Stecker, Floyd W.; Scully, Sean T.

2009-01-01

402

Low-Energy Cosmic-Ray Events Associated with Solar Flares  

Microsoft Academic Search

As a result of the IGY riometer program, it has been found that the measure- ment of ionospheric absorption in arctic regions is a sensitive method of detecting low-energy cosmic rays associated with solar flares. The normal morphology of these events is described, and details are given of the 24 such events that have been detected in the period from

George C. Reid; Harold Leinbach

1959-01-01

403

Peculiar high energy cosmic ray stratospheric event reveals a heavy primary origin particle above the knee region of the cosmic ray spectrum  

SciTech Connect

We wish to put forward an explanation for a peculiar cosmic ray event with energy {sigma}E{sub {gamma}}{>=}2x10{sup 15} eV detected in 1975 by the balloon borne emulsion chamber experiment performed in the stratosphere, at the altitude {>=}30 km above sea level. For almost 30 years the event has been described as unusual, invoking new exotic mechanisms or models. In our opinion there is no need for an extraordinary explanation. Contrary to the widespread belief, the event gives us an example of 'unrecognized standard physics'. At the same time this event revealed a variety of features which are of considerable interest for cosmic rays, nuclear physics, and astrophysics. Here we show that the observed family is most likely to be a result of a heavy nucleus interaction with an air nucleus. In this case a primary particle would originally have been in the energy region above 'the knee' of the cosmic ray spectrum.

Kopenkin, V.; Fujimoto, Y. [Advanced Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo, 169 (Japan)

2005-01-15

404

Cosmic Ray Interactions and the Abundances of the Chemical Elements  

E-print Network

Our Galaxy is the largest nuclear interaction experiment which we know, because of the interaction between cosmic ray particles and the interstellar material. Cosmic rays are particles, which have been accelerated in the Galaxy or in extragalactic space. Cosmic rays come as protons, electrons, heavier nuclei, and their antiparticles. Up to energies up to some tens of TeV of particle energy it is possible to derive chemical abundances of cosmic rays. It has been proposed that cosmic ray particles can be attributed to three main sites of origin and acceleration, a) supernova shocks in the interstellar medium, b) supernova shocks in a stellar wind of the predecessor star, and c) powerful radio galaxies. This proposal leads to quantitative tests, which are encouraging sofar. Quantitative models for transport and interaction appear to be consistent with the data. Li, Be, B are secondary in cosmic rays, as are many of the odd-Z elements, as well as the sub-Fe elements. At very low energies, cosmic ray particles are subject to ionization losses, which produce a steep low energy cutoff; all particles below the cutoff are moved into the thermal material population, and the particles above it remain as cosmic rays. This then changes the chemical abundances in the interstellar medium, and is a dominant process for many isotopes of Li, Be, B. With a quantitative theory for the origin of cosmic rays proposed, it appears worthwhile to search for yet better spallation cross sections, especially near threshold. With such an improved set of cross sections, the theory of the interstellar medium and its chemical abundances, both in thermal and in energetic particles, could be taken a large step forward.

Peter L. Biermann

1996-09-17

405

Origin of Galactic Cosmic Rays from Supernova Remnants  

NASA Astrophysics Data System (ADS)

We analyze the results of recent measurements of Galactic cosmic ray (GCRs) energy spectra and the spectra of nonthermal emission from supernova remnants (SNRs) in order to determine their consistency with GCR origin in SNRs. It is shown that the measured primary and secondary CR nuclei energy spectra as well as the observed positron-to-electron ratio are consistent with the origin of GCRs up to the energy 1017 eV in SNRs. Existing SNR emission data provide evidences for efficient CR production in SNRs accompanied by significant magnetic field amplification. In some cases the nature of the detected ?-ray emission is difficult to determine because key SNR parameters are not known or poorly constrained.

Berezhko, E. G.

2014-11-01

406

Change in cosmic-ray spectrum through the production of electron-positron pairs (analytical approach)  

SciTech Connect

We consider the change in primordial cosmic-ray spectrum through the production of electron-positron pairs in collisions with cosmic microwave background radiation photons. We suggest using these results to estimate the distances to cosmic-ray sources.

Vlasov, V. P., E-mail: vlasov@nfi.kiae.ru; Trubnikov, B. A., E-mail: batrub@nfi.kiae.r [Russian Research Center Kurchatov Institute (Russian Federation)

2009-12-15

407

Antarctic radio frequency albedo and implications for cosmic ray reconstruction  

NASA Astrophysics Data System (ADS)

We describe herein a measurement of the Antarctic surface "roughness" performed by the balloon-borne ANITA (Antarctic Impulsive Transient Antenna) experiment. Originally purposed for cosmic ray astrophysics, the radio frequency (RF) receiver ANITA gondola, from its 38 km altitude vantage point, can scan a disk of snow surface 600 km in radius. The primary purpose of ANITA is to detect RF emissions from cosmic rays incident on Antarctica, such as neutrinos which penetrate through the atmosphere and interact within the ice, resulting in signal directed upward which then refracts at the ice-air interface and up and out to ANITA, or high-energy nuclei (most likely irons or protons), which interact in the upper atmosphere (at altitudes below ANITA) and produce a spray of down-coming RF which reflects off the snow surface and back up to the gondola. The energy of such high-energy nuclei can be inferred from the observed reflected signal only if the surface reflectivity is known. We describe herein an attempt to quantify the Antarctic surface reflectivity, using the Sun as a constant, unpolarized RF source. We find that the reflectivity of the surface generally follows the expectations from the Fresnel equations, lending support to the use of those equations to give an overall correction factor to calculate cosmic ray energies for all locations in Antarctica. The analysis described below is based on ANITA-II data. After launching from McMurdo Station in December 2008, ANITA-II was aloft for a period of 31 days with a typical instantaneous duty cycle exceeding 95%.

Besson, D. Z.; Stockham, J.; Sullivan, M.; Allison, P.; Beatty, J. J.; Belov, K.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Dowkontt, P. F.; Gorham, P. W.; Hoover, S.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Miki, C.; Mottram, M.; Nam, J.; Naudet, C. J.; Nichol, R. J.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Shang, R. Y.; Stockham, M.; Varner, G. S.; Vieregg, A. G.; Wang, Y.

2015-01-01

408

Constraints on particle dark matter from cosmic-ray antiprotons  

E-print Network

Cosmic-ray antiprotons represent an important channel for dark matter indirect-detection studies. Current measurements of the antiproton flux at the top of the atmosphere and theoretical determinations of the secondary antiproton production in the Galaxy are in good agreement, with no manifest deviation which could point to an exotic contribution in this channel. Therefore, antiprotons can be used as a powerful tool for constraining particle dark matter properties. By using the spectrum of PAMELA data from 50 MV to 180 GV in rigidity, we derive bounds on the dark matter annihilation cross section (or decay rate, for decaying dark matter) for the whole spectrum of dark matter annihilation (decay) channels and under different hypotheses of cosmic-rays transport in the Galaxy and in the heliosphere. For typical models of galactic propagation, the constraints are significantly strong, setting a lower bound on the dark matter mass of a "thermal" relic at about 50-90 GeV for hadronic annihilation channels. These bounds are enhanced to about 150 GeV on the dark matter mass, when large cosmic-rays confinement volumes in the Galaxy are considered, and are reduced to 4-5 GeV for annihilation to light quarks (no bound for heavy-quark production) when the confinement volume is small. Bounds for dark matter lighter than few tens of GeV are due to the low energy part of the PAMELA spectrum, an energy region where solar modulation is relevant: to this aim, we have implemented a detailed solution of the transport equation in the heliosphere, which allowed us not only to extend bounds to light dark matter, but also to determine the uncertainty on the constraints arising from solar modulation modeling. Finally, we estimate the impact of soon-to-come AMS-02 data on the antiproton constraints.

N. Fornengo; L. Maccione; A. Vittino

2015-01-30

409

Cosmic rays IX. Interactions and transport of cosmic rays in the Galaxy  

NASA Astrophysics Data System (ADS)

We propose that cosmic rays interact mostly near their sources of origin. To be specific, we differentiate the various supernovae by their mass of the progenitor star along the zero age main sequence. Stars between about 8 and 15 solar masses explode into the interstellar medium, and accelerate cosmic rays, as discussed by many for some time. From about 15 to 25 solar masses stars explode into their own stellar wind; this wind has built up a thin shell of both wind material and interstellar medium material in the red and blue giant phases preceding the supernova event. The shock accelerating cosmic ray particles races through that wind, gets loaded up with energetic particles, interacts while it goes, and finally smashes into the shell. While the shock goes out, it snowplows the entire wind into the pre-existing shell to form a composite shell. We propose that for the mass range 15 to 25 solar masses this composite shell is immediately broken up so that the time scale for interaction is caused by the breakup and so is convective. We note that the wind material for this range of zero age masses is a approximately half helium, and half hydrogen. The interactions in the composite wind-shell and the immediate environment produce positrons, gamma emission, but only few secondary nuclei, because for this mass range the enrichment in heavier elements is still minor. The energy spectrum of the gamma emission and the positrons produced corresponds then to the source spectrum. In contrast, from about 25 solar masses and up the wind is strongly enriched in heavy elements, and the wind shell is massive, comprising most of the initial zero age star's mass, as well as a good part of the local interstellar medium. We propose that for the interaction of the cosmic ray particles carried out by the shock in the snow-plow through the wind to the shell the interaction is diffusive, and calculate the diffusion coefficient. This leads to a leakage time energy dependence of E-5/9 in the relativistic limit. This then gives an energy dependence of secondary nuclei, that matches the observations. There is a second component of positrons, and also gamma emission, but then at moderate energies all with the steeper energy dependence; spatial and velocity constraints give both a lower as well as an upper rigidity limit to the diffusion approximation. One important element in such a picture is the steady mixing of newly enriched material throughout the star before the explosion, induced by Voigt-Eddington circulation caused by rotation. The mixed material is then ejected through the wind, which at the end provides the source material for cosmic ray injection. This means that by the time the nuclei are subject to acceleration, they should have decayed already to final states, an effect which may be measureable in cosmic ray isotope ratios. Therefore, considering the history of the travel of cosmic rays through the normal interstellar medium, we can readily explain the ratio of secondaries to primaries, and at the same time use a spectrum of turbulence in the interstellar medium, a Kolmogorov spectrum, which is consistent with all other observational evidence. The escape time from the Galaxy is then proportional to E-1/3 in the relativistic range of particle energies. Translating this result into the language common in the literature, this means that interaction path as measured in gm/cm2 and escape time can not be used synonymously.

Biermann, P. L.; Langer, N.; Seo, Eun-Suk; Stanev, T.

2001-04-01

410

Galactic Propagation of Cosmic Rays from Individual Supernova Remnants  

E-print Network

It is widely believed that supernova remnants are the best candidate sources for the observed cosmic ray flux up to the knee, i.e. up to ~PeV energies. Indeed, the gamma-ray spectra of some supernova remnants can be well explained by assuming the decay of neutral pions which are created in hadronic interactions. Therefore, fitting the corresponding gamma spectra allows us to derive the spectra of cosmic rays at the source which are locally injected into our Galaxy. Using these spectra as a starting point, we propagate the cosmic rays through the Galaxy using the publicly available GALPROP code. Here, we will present first results on the contribution of those SNRs to the total cosmic ray flux and discuss implications.

Nierstenhoefer, Nils; Schuppan, Florian; Tjus, Julia Becker

2015-01-01

411

Calculations of cosmic-ray helium transport in shielding materials  

NASA Technical Reports Server (NTRS)

The transport of galactic cosmic-ray helium nuclei and their secondaries through bulk shielding is considered using the straight-ahead approximation to the Boltzmann equation. A data base for nuclear interaction cross sections and secondary particle energy spectra for high-energy light-ion breakup is presented. The importance of the light ions H-2, H-3, and He-3 for cosmic-ray risk estimation is discussed, and the estimates of the fractional contribution to the neutron flux from helium interactions compared with other particle interactions are presented using a 1977 solar minimum cosmic-ray spectrum.

Cucinotta, Francis A.

1993-01-01

412

The survival of heavy nuclei in cosmic ray source environments  

NASA Technical Reports Server (NTRS)

The results are discussed that were obtained from the Goddard balloon spectrometer experiment to study the composition and energy distribution of high energy cosmic rays. The significant findings indicate that: (1) On a total energy scale, protons constitute only a minor proportion of the cosmic rays. They account for only 20 percent; the rest of the cosmic rays are complex nuclei. (2) All the nuclei have the same power low spectrum in total energy and so the composition appears to be independent of energy.

Balasubrahmanyan, V. K.

1972-01-01

413

A connection between star formation activity and cosmic rays in the starburst galaxy M82  

NASA Astrophysics Data System (ADS)

Although Galactic cosmic rays (protons and nuclei) are widely believed to be mainly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size-more than 50 times the diameter of similar Galactic regions-uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density. The cosmic rays produced in the formation, life and death of massive stars in these regions are expected to produce diffuse ?-ray emission through interactions with interstellar gas and radiation. M82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in terms of ?-ray emission. Here we report the detection of >700-GeV ?-rays from M82. From these data we determine a cosmic-ray density of 250eVcm-3 in the starburst core, which is about 500 times the average Galactic density. This links cosmic-ray acceleration to star formation activity, and suggests that supernovae and massive-star winds are the dominant accelerators.

VERITAS Collaboration; Acciari, V. A.; Aliu, E.; Arlen, T.; Aune, T.; Bautista, M.; Beilicke, M.; Benbow, W.; Boltuch, D.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Celik, O.; Cesarini, A.; Chow, Y. C.; Ciupik, L.; Cogan, P.; Colin, P.; Cui, W.; Dickherber, R.; Duke, C.; Fegan, S. J.; Finley, J. P.; Finnegan, G.; Fortin, P.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Gibbs, K.; Gillanders, G. H.; Godambe, S.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Holder, J.; Horan, D.; Hui, C. M.; Humensky, T. B.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D.; Kildea, J.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Lebohec, S.; Maier, G.; McArthur, S.; McCann, A.; McCutcheon, M.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nagai, T.; Ong, R. A.; Otte, A. N.; Pandel, D.; Perkins, J. S.; Pizlo, F.; Pohl, M.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Smith, A. W.; Steele, D.; Swordy, S. P.; Theiling, M.; Thibadeau, S.; Varlotta, A.; Vassiliev, V. V.; Vincent, S.; Wagner, R. G.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Williams, D. A.; Wissel, S.; Wood, M.; Zitzer, B.

2009-12-01

414

Solar Variability, Cosmic Rays and Climate: What's up? The topic of possible relations between solar and cosmic  

E-print Network

Preface Solar Variability, Cosmic Rays and Climate: What's up? The topic of possible relations between solar and cosmic ray variability on one hand, and Earth's climate on the other hand, is quite in Space Research topical issue on Solar Variability, Cosmic Rays and Climate presents a collection

Usoskin, Ilya G.

415

Cosmic Ray Sampling of a Clumpy Interstellar Medium  

E-print Network

How cosmic rays sample the multi-phase interstellar medium (ISM) in starburst galaxies has important implications for many science goals, including evaluating the cosmic ray calorimeter model for these systems, predicting their neutrino fluxes, and modeling their winds. Here, we use Monte Carlo simulations to study cosmic ray sampling of a simple, two-phase ISM under conditions similar to those of the prototypical starburst galaxy M82. The assumption that cosmic rays sample the mean density of the ISM in the starburst region is assessed over a multi-dimensional parameter space where we vary the number of molecular clouds, the galactic wind speed, the extent to which the magnetic field is tangled, and the cosmic ray injection mechanism. We evaluate the ratio of the emissivity from pion production in molecular clouds to the emissivity that would be observed if the cosmic rays sampled the mean density, and seek areas of parameter space where this ratio differs significantly from unity. The assumption that cosmic...

Boettcher, Erin; Yoast-Hull, Tova M; Gallagher, J S

2013-01-01

416

Prospects for Detecting a Cosmic Bulk Flow  

NASA Astrophysics Data System (ADS)

The ?CDM model is based upon a homogeneous, isotropic space-time leading to uniform expansion with random peculiar velocities caused by local gravitation perturbations. The Cosmic Microwave Background (CMB) radiation evidences a significant dipole moment in the frame of the Local Group. This motion is usually explained with the Local Group's motion relative to the background Hubble expansion. An alternative explanation, however, is that the dipole moment is the result of horizon-scale curvature remaining from the birth of space-time, possibly a result of quantum entanglement with another universe. This would appear as a single velocity (a bulk flow) added to all points in space. These two explanations differ observationally on cosmic distance scales (z > 0.1). There have been many differing attempts to detect a bulk flow, many with no detectable bulk flow but some with a bulk flow velocity as large as 1000 km/s. Here we report on a technique based upon minimizing the scatter around the expected cosine distribution of the Hubble redshift residuals with respect to angular distance on the sky. That is, the algorithm searches for a directional dependence of Hubble residuals. We find results consistent with most other bulk flow detections at z < 0.05, i.e. a bulk flow velocity of ~300 km/s pointed at (l, b) = (280, 29) in galactic coordinates. Simulations were run to analyze whether a bulk flow can be detected at higher redshifts, z < 0.3. For detecting a bulk flow velocity of <1,000 km/s at such distances one would need distance modulus errors from Type Ia Supernovae to be ~0.01, whereas the current error (~0.2.) is more than an order of magnitude too large for the detection of bulk flow beyond z~0.05.

Rose, Benjamin; Garnavich, Peter M.; Mathews, Grant James

2015-01-01

417

Separation of the electron and proton cosmic-ray components by means of a calorimeter in the PAMELA satellite-borne experiment for the case of particle detection within a large aperture  

SciTech Connect

The PAMELA satellite-borne experiment is designed to study cosmic rays over a broad energy range. The apparatus has been in near-Earth cosmic space from June 2006 to the present time. It is equipped with a magnetic spectrometer for determining the sign of the particle charge and rigidity. In solving some problems, however, information from the magnetic spectrometer becomes inaccessible, so that it is necessary to employ a calorimeter to separate the electron and nuclear cosmic-ray components. A procedure for separating these components for particles arriving off the magnetic-spectrometer aperture is considered.

Karelin, A. V., E-mail: karelin@hotbox.ru; Borisov, S. V.; Voronov, S. A.; Malakhov, V. V. [National Research Nuclear University MEPhI (Russian Federation)

2013-06-15

418

Relationships between cosmic ray neutron flux and rain flows in dependence on different latitudes and altitudes  

Microsoft Academic Search

A convenient tool for investigation of primary cosmic ray variations is the registration of secondary cosmic ray neutrons. A network of neutron monitors, aiming the studies of cosmic ray variations exists. At the same time cosmic ray variations may be related to some atmospheric processes. In this connection, using the data from Moskow neutron monitor (latitude 55 degree) and lead

Peter Velinov; Anatolii Belov; Viktor Yanke; Evgenia Eroshenko; Alexander Mishev; Yordan Tassev

2008-01-01

419

Groping for the (cosmic-ray) knee Frank Jones, Robert Streitmatter, and Demos Kazanas  

E-print Network

Groping for the (cosmic-ray) knee Frank Jones, Robert Streitmatter, and Demos Kazanas Exploring the possibility that the cosmic-ray knee is produced by a change in the nature of the hadronic interaction explanation of the cosmic-ray knee asserts that the spectrum of supernova produced cosmic rays ends

420

The Cosmic-ray Spectrum: from the knee to the T K Gaisser  

E-print Network

The Cosmic-ray Spectrum: from the knee to the ankle T K Gaisser Bartol Research Institute the question, "Where is the transition from cosmic rays of galactic origin to extra-galactic cosmic-rays?" I It is a commonplace, nearly a century after the discovery of cosmic rays, that their origin remains a mystery

421

The Quest for Cosmic Ray Protons in Galaxy Clusters  

NASA Astrophysics Data System (ADS)

There have been many speculations about the presence of cosmic ray protons (CRps) in galaxy clusters over the past two decades. However, no direct evidence such as the characteristic ?-ray signature of decaying pions has been found so far. These pions would be a direct tracer of hadronic CRp interactions with the ambient thermal gas also yielding observable synchrotron and inverse Compton emission by additionally produced secondary electrons. The obvious question concerns the type of galaxy clusters most likely to yield a signal: Particularly suited sites should be cluster cooling cores due to their high gas and magnetic energy densities. We studied a nearby sample of clusters evincing cooling cores in order to place stringent limits on the cluster CRp population by using non-detections of EGRET. In this context, we examined the possibility of a hadronic origin of Coma-sized radio halos as well as radio mini-halos. Especially for mini-halos, strong clues are provided by the very plausible small amount of required CRp energy density and a matching radio profile. Introducing the hadronic minimum energy criterion, we show that the energetically favored CRp energy density is constrained to 2% ± 1% of the thermal energy density in Perseus. We also studied the CRp population within the cooling core region of Virgo using the TeV ?-ray detection of M 87 by HEGRA. Both the expected radial ?-ray profile and the required amount of CRp support this hadronic scenario.

Pfrommer, C.; Enßlin, T. A.

2004-12-01

422

EFFECT OF COSMIC MICROWAVE BACKGROUND ON X-RAY  

E-print Network

EFFECT OF COSMIC MICROWAVE BACKGROUND ON X-RAY RADIATION OF HIGH REDSHIFT JETS Kathryn McKeough1;Introduction & Background ¨ Inverse Compton (IC) Scattering ¨ Cosmic Microwave Background (CMB) ­ relativistic, USA 3. Harvard University, 1 Oxford St, Cambridge MA 02318, USA #12;Introduction & Background

Wolfe, Patrick J.

423

Exploring Cosmic X-ray Source Polarization  

NASA Technical Reports Server (NTRS)

Cosmic X-ray sources are expected to be polarized, either because of their asymmetry and the role of scattering in their emission or the role of magnetic fields. Polarization at other wavelengths has been useful. X-ray polarization will provide a new handle on black hole parameters, in particular the spin, on accretion flows and outflows, on neutron star spin orientations and emission mechanisms, on the quantum mechanical effects of super-strong magnetic fields of magnetars, and on the structure of supernovae shocks. The proposed Gravity and Extreme Magnetism SMEX (GEMS) will use high efficiency polarimeters behind thin foil mirrors. The statistical sensitivity and control of systematics will allow measurement of polarization fractions as small as 1% from many galactic and extragalactic sources. Targets which should be polarized at the level that GEMS can easily measure include stellar black holes, Seyfert galaxies and quasars, blazars, rotation-powered and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. The polarimeters are Time Projection Chambers that allow reconstruction of images of photoelectron tracks for 2-10 keV Xrays. They can be deep without sacrificing modulation. These polarimeters do not image the sky, but the telescope point spread function and detector collimation allow structure to be resolved at the 10 arcmin level. Rotation of the spacecraft is not needed for the signal measurement in the Time Projection Chambers, but provides for measurement and correction of systematic errors. It also allows a small Bragg reflection soft X-ray experiment to be included that can be used for isolated neutron stars and blazars.

Swank, Jean Hebb; Jahodal, K.; Kallman, T. R.; Kaaret, P.

2008-01-01

424

Cosmic ray streaming in clusters of galaxies  

NASA Astrophysics Data System (ADS)

The observed bimodality in radio luminosity in galaxy clusters is puzzling: cosmic rays (CRs) accelerated by structure formation shocks are expected to indiscriminately produce bright radio haloes in every cluster. We investigate the possibility that CR streaming in the intracluster medium (ICM) can `switch off' hadronically induced radio and gamma-ray emission. For self-confined CRs, this depends on the source of magnetohydrodynamic wave damping: if only non-linear Landau damping operates, then CRs stream on the slow Alfvénic time-scale, but if turbulent wave damping operates, super-Alfvénic streaming is possible. As turbulence increases, it promotes outward streaming more than it enables inward turbulent advection. Curiously, the CR flux is independent of ?f (as long as it is non-zero) and depends only on plasma parameters; this enables radio haloes with flat inferred CR profiles to turn off. We perform 1D time-dependent calculations of a radio mini-halo (Perseus) and giant radio halo (Coma) and find that both diminish in radio luminosity by an order of magnitude in several hundred Myr, given plausible estimates for the magnetic field in the outskirts of the cluster. Due to the energy dependence of CR streaming, spectral curvature develops, and radio haloes turn off more slowly at low frequencies - properties consistent with observations. Similarly, CR streaming rapidly turns off gamma-ray emission at the high energies probed by Cherenkov telescopes, but not at the low energies probed by Fermi. CR mediated wave heating of the ICM is unaffected, as it is dominated by ˜GeV CRs which stream Alfvénically.

Wiener, Joshua; Oh, S. Peng; Guo, Fulai

2013-09-01

425

The Origin of Cosmic Rays: What can GLAST Say?  

NASA Technical Reports Server (NTRS)

Gamma rays in the band from 30 MeV to 300 GeV, used in combination with direct measurements and with data from radio and X-ray bands, provide a powerful tool for studying the origin of Galactic cosmic rays. Gamma-ray Large Area Space Telescope (GLAST) with its fine 10-20 arcmin angular resolution will be able to map the sites of acceleration of cosmic rays and their interactions with interstellar matter, It will provide information that is necessary to study the acceleration of energetic particles in supernova shocks, their transport in the interstellar medium and penetration into molecular clouds.

Ormes, Jonathan F.; Digel, Seith; Moskalenko, Igor V.; Moiseev, Alexander; Williamson, Roger

2000-01-01

426

The History of Cosmic Ray Studies after Hess  

NASA Astrophysics Data System (ADS)

The discovery of cosmic rays by Victor Hess was confirmed with balloon flights at higher altitudes by Kolhörster. Soon the interest turned into questions about the nature of cosmic rays: gamma rays or particles? Subsequent investigations have established cosmic rays as the birthplace of elementary particle physics. The 1936 Nobel prize was shared between Victor Hess and Carl Anderson. Anderson discovered the positron in a cloud chamber. The positron was predicted by Dirac several years earlier. Many new results came now from studies with cloud chambers and nuclear emulsions. Anderson and Neddermeyer saw the muon, which for some time was considered to be a candidate for the Yukawa particle responsible for nuclear binding. Lattes, Powell, Occhialini and Muirhead clarified the situation by the discovery of the charged pions in cosmic rays. Rochester and Butler found V's, which turned out to be short-lived neutral kaons decaying into a pair of charged pions. ?'s, ?'s and ?'s were found in cosmic rays using nuclear emulsions. After that period, accelerators and storage rings took over. The unexpected renaissance of cosmic rays started with the search for solar neutrinos and the observation of the supernova 1987A and other accelerators in the sky. With the observation of neutrino oscillations one began to look beyond the standard model of elementary particles. After 100 years of cosmic ray research we are again at the beginning of a new era, and cosmic rays may contribute to solve the many open questions, like dark matter and dark energy, by providing energies well beyond those of earth-bound accelerators.

Grupen, Claus

2013-06-01

427

Are extragalactic gamma ray bursts the source of the highest energy cosmic rays?  

E-print Network

Recent observations with the large air shower arrays of ultra high energy cosmic rays (UHECR) and recent measurements/estimates of the redshifts of gamma ray bursts (GRBs) seem to rule out extragalactic GRBs as the source of the cosmic rays that are observed near Earth, including those with the highest energies.

Arnon Dar

1999-01-03

428

A local recent supernova - Evidence from X-rays, Al-26 radioactivity and cosmic rays  

NASA Technical Reports Server (NTRS)

Possible ways in which cosmic rays could have been contaminated by a local recent supernova are discussed, and ways in which this contamination may be affecting interpretation of Al-26 gamma radiation and locally observed cosmic rays as samples of the average Galactic distribution are considered. Mass spectra of cosmic rays are examined to see whether there is enrichment by a population arising from supernova preacceleration. The reinterpretation of the anomalous component in terms of a local supernova model is addressed.

Clayton, Donald D.; Cox, Donald P.; Michel, Curtis F.

1986-01-01

429

Scintillation Light from Cosmic-Ray Muons in Liquid Argon  

E-print Network

This paper reports the results of the first experiment to directly measure the properties of the scintillation light generated by minimum ionizing cosmic-ray muons in liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches, as well as for particle identification. The experiment was carried out at the TallBo facility at Fermilab using prototype light guides and electronics developed for the Long-Baseline Neutrino Experiment. Analysis of the time-resolved structure of the scintillation light from cosmic-ray muons gives $\\langle \\tau_{\\text{T}}\\rangle = 1.43 \\pm 0.04~\\text{(stat.)} \\pm 0.007~\\text{(sys.)}~\\mu$s for the triplet light decay time constant. The ratio of singlet to triplet light measured using surface-coated light guides is $R = 0.39 \\pm 0.01~\\text{(stat.)} \\pm 0.008~\\text{(sys.)}$. There is some evidence that this value is not consistent with $R$ for minimum ionizing electrons. However, the value for $R$ measured here clearly differs significantly from $R$ found for heavily ionizing particles like alphas. Furthermore, there is no apparent difference in $R$ measured using light guides coated with TPB versus bis-MSB, adding additional evidence that bis-MSB is a promising alternative to TPB for detecting scintillation light in liquid argon.

Denver Whittington; Stuart Mufson

2014-08-08

430

Diffusive cosmic-ray acceleration at the Galactic Centre  

NASA Astrophysics Data System (ADS)

The diffuse TeV emission detected from the inner ˜2° of the Galaxy appears to be strongly correlated with the distribution of molecular gas along the Galactic ridge. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the molecular gas strongly points to a pionic-decay process involving relativistic protons. However, the spectrum of the TeV radiation - a power law with index ??-2.3- cannot be accommodated easily with the much steeper distribution of cosmic rays seen at the Earth. In earlier work, we examined the possible sources of these relativistic protons and concluded that neither the supermassive black hole Sagittarius A*[identified with the High-Energy Stereoscopic System (HESS) source J1745-290] nor several pulsar wind nebulae dispersed along the Galactic plane could produce a TeV emission profile morphologically similar to that seen by the HESS. We concluded from this earlier study that only relativistic protons accelerated throughout the intercloud medium could account for the observed diffuse TeV emission from this region. In this Letter, we develop a model for diffusive proton acceleration driven by a turbulent Alfvénic magnetic field present throughout the gaseous medium. Though circumstantial, this appears to be the first evidence that at least some cosmic rays are accelerated diffusively within the inner ˜300 pc of the Galaxy.

Melia, F.; Fatuzzo, M.

2011-01-01

431

Industrial radiography with cosmic-ray muons: A progress report  

NASA Astrophysics Data System (ADS)

Cosmic-ray produced muons arrive at the surface of the earth with enormous energies ranging up to 1012 GeV. There have been sporadic attempts to exploit their extreme penetration through matter to probe the internal structures of very large objects, including an Egyptian pyramid and a volcano but their very low intensity per unit area ( ?1 cm-2 per min) generally restricts the practicably attainable spatial resolution to large dimensions. Nevertheless the more intense low energy region of the muon spectrum has recently been shown to be capable of detecting high-Z objects with dimensions of the order of 10 cm hidden inside large transport containers in measurement times of minutes. These various developments have encouraged further studies of potential industrial uses of cosmic-ray muons in industrial applications. In order to gain maximum benefit from the low muon flux large area detectors are required and plastic scintillators offer useful advantages in size, cost and simplicity. Scintillator slabs up to 1 m2 square and 76.2 mm thick are undergoing testing for applications in the nuclear industry. The most direct approach employs photomultiplier tubes at each corner to measure the relative sizes of muon induced pulses to determine the location of each muon track passing through the scintillator. The performance of this technique is reported and its imaging potential is assessed.

Gilboy, W. B.; Jenneson, P. M.; Simons, S. J. R.; Stanley, S. J.; Rhodes, D.

2007-09-01

432

Antarctic Radio Frequency Albedo and Implications for Cosmic Ray Reconstruction  

E-print Network

From an elevation of ~38 km, the balloon-borne ANtarctic Impulsive Transient Antenna (ANITA) is designed to detect the up-coming radio frequency (RF) signal resulting from a sub-surface neutrino-nucleon collision. Although no neutrinos have been discovered thus far, ANITA is nevertheless the only experiment to self-trigger on radio frequency emissions from cosmic-ray induced atmospheric air showers. In the majority of those cases, down-coming RF signals are observed via their reflection from the Antarctic ice sheet and back up to the ANITA interferometer. Estimating the energy scale of the incident cosmic rays therefore requires an estimate of the fractional power reflected at the air-ice interface. Similarly, inferring the energy of neutrinos interacting in-ice from observations of the upwards-directed signal refracting out to ANITA also requires consideration of signal coherence across the interface. By comparing the direct Solar RF signal intensity measured with ANITA to the surface-reflected Solar signal ...

Besson, D Z; Sullivan, M; Allison, P; Barwick, S W; Baughman, B M; Beatty, J J; Belov, K; Bevan, S; Binns, W R; Chen, C; Chen, P; Clem, J M; Connolly, A; De Marco, D; Dowkontt, P F; DuVernois, M; Goldstein, D; Gorham, P W; Grashorn, E W; Hill, B; Hoover, S; Huang, M; Israel, M H; Javaid, A; Kowalski, J; Learned, J; Liewer, K M; Matsuno, S; Mercurio, B C; Miki, C; Mottram, M; Nam, J; Naudet, C J; Nichol, R J; Palladino, K; Romero-Wolf, A; Ruckman, L; Saltzberg, D; Seckel, D; Shang, R Y; Stockham, M; Varner, G S; Vieregg, A G; Wang, Y

2013-01-01

433

EMMA-a new underground cosmic-ray experiment  

SciTech Connect

An experiment observing underground muons originating from cosmic-ray air showers is under preparation in the Pyhaesalmi mine, Finland. The aim is to cover an area of about 200-300 m{sup 2}, and the detector setup is capable of measuring the muon multiplicity and their lateral distribution. The detector is placed at a depth of about 85 m (corresponding about 240 m w.e.), which gives a threshold energy of muons of about 45 GeV. The detection of the multimuon events is motivated by partly unknown composition of the primary cosmic rays in the energy region of 10{sup 15}-10{sup 16} eV, i.e., the knee region. In addition, by measuring only the higher energy muons of the air shower, the lowest energy muons being filtered out by the rock overburden, the data is sensitive also to the studies of the upper parts of the air shower. The experiment will be constructed mainly using drift chambers used previously in LEP detectors at CERN, but it can also be expanded using plastic scintillator detectors. The prototype detector is expected to be running in the beginning of 2006, and the full-size detector by the end of 2007.

Enqvist, T., E-mail: timo.enqvist@oulu.fi; Foehr, V.; Joutsenvaara, J. [CUPP (Finland); Keraenen, P. [University of Jyvaeskylae, Department of Physics (Finland); Kuusiniemi, P. [CUPP (Finland); Laitala, H.; Lehtola, M.; Mattila, A.; Narkilahti, J.; Nurmenniemi, S.; Peltoniemi, J.; Remes, H.; Raeihae, T. [University of Oulu, CUPP (Finland); Shen, C.; Reponen, M. [CUPP (Finland); Sarkamo, J.; Vaittinen, M. [University of Oulu, CUPP (Finland); Zhang, Z. [CUPP (Finland); Jaemsen, T. [University of Oulu, SGO (Finland); Ding, L. [Chinese Academy of Sciences, IHEP (China)] (and others)

2007-01-15

434

Real-time cosmic ray monitoring system for space weather  

NASA Astrophysics Data System (ADS)

We have developed a real-time system to monitor high-energy cosmic rays for use in space weather forecasting and specification. Neutron monitors and muon detectors are used for our system, making it possible to observe cosmic rays with dual energy range observations. In large solar energetic particle (SEP) events, the ground level enhancement (GLE) can provide the earliest alert for the onset of the SEP event. The loss cone precursor anisotropy predicts the arrival of interplanetary shocks and the associated interplanetary coronal mass ejections (ICMEs), while the occurrence of bidirectional cosmic ray streaming indicates that Earth is within a large ICME. This article describes a set of real-time Web displays that clearly show the appearance of the GLE, loss cone precursor, and other space weather phenomena related to cosmic rays.

Kuwabara, T.; Bieber, J. W.; Clem, J.; Evenson, P.; Pyle, R.; Munakata, K.; Yasue, S.; Kato, C.; Akahane, S.; Koyama, M.; Fujii, Z.; Duldig, M. L.; Humble, J. E.; Silva, M. R.; Trivedi, N. B.; Gonzalez, W. D.; Schuch, N. J.

2006-08-01

435

A Search for Antimatter in the Cosmic Rays  

NASA Astrophysics Data System (ADS)

This work concerns the study of the composition of cosmic rays with two balloon-borne instruments, SMILI (Superconducting Magnetic Instrument for Light Isotopes), and MAGPIE (MAGnetic Passive Isotope Experiment). The principal result of this thesis is a new upper limit on the fraction of antihelium in the cosmic rays. This result, based on a sample of 16,000 helium events, limits the amount of antimatter that can be present in our Galaxy. Also presented are new data analysis techniques that have been developed to determine the masses of the light cosmic ray nuclei (lithium, beryllium, and boron) with unprecedented precision. In addition, this thesis contains a description of the analysis of nuclear tracks in the detectors of MAGPIE, a prototype apparatus flown from Antarctica to explore novel techniques for improved measurements of cosmic ray composition.

Greene, Nathaniel R.

1997-01-01

436

Supernova envelope shock origin of cosmic rays: a review  

SciTech Connect

The hydrodynamic shock origin of cosmic rays in the envelope of a Type I presupernova star is reviewed. The possibility of accelerating ultrahigh energy particles to greater than or equal to 10/sup 18/ eV is unique to the shock mechanism and currently no other suggested galactic or extragalactic site is likely. In this paper a review of the work leading to a renewed commitment to the origin of cosmic rays in the shock ejected envelope of supernova is given. The degree to which this interpretation applies to the origin of all cosmic rays is certainly uncertain and does not exclude the possibility of a fraction of the lower energy cosmic rays being accelerated in collisionless plasma shocks in the interstellar medium. 45 references, 3 figures.

Colgate, S.A.

1984-01-01

437

Heliosphere Changes Affect Cosmic Ray Penetration - Duration: 0:18.  

NASA Video Gallery

The changes in the size of our solar systemâ??s boundaries also cause changes to the galactic cosmic rays that enter the solar system. Although these boundaries do a good job of deflecting the majo...

438

The Determination of the Muon Magnetic Moment from Cosmic Rays  

ERIC Educational Resources Information Center

Describes an experiment suited for use in an advanced laboratory course in particle physics. The magnetic moment of cosmic ray muons which have some polarization is determined with an error of about five percent. (Author/GS)

Amsler, C.

1974-01-01

439

Studies of cosmic rays with the anticoincidence system  

E-print Network

.1 A Brief History of Cosmic Rays . . . . . . ., a time of flight system, a scintillator-based anticoincidence (AC) system, a tail catcher scintillator. The timing and multiplicity of AC activity correlated to particle triggers has been studied. A dependence

Haviland, David

440

Refractory nuclides in the cosmic-ray source  

NASA Technical Reports Server (NTRS)

New observations of the abundances and energy spectra of the isotopes of Mg, Al, and Si from ACE/CRIS are used to extend our previous results on the composition of refractory nuclides in cosmic-ray source material.

Wiedenbeck, M. E.; Binns, W. R.; Cummings, A. C.; Davis, A. J.; Nolfo, G. de; George, J. S.; Israel, M. H.; Labrador, A. W.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; Rosenvinge, T. T. von

2003-01-01

441

Cosmic-Ray Effects of Propagating Shocks Including the Heliosheath  

NASA Astrophysics Data System (ADS)

It has been known for a long time (Jokipii, et al, 1993) that the e~@ects of tt he heliosphere on cosmic rays extends beyond the termination shock and into the heliosheath. The inclusion of the region beyond the termination shock into models of modulation is still relatively recent. The previously-published model resultshave all been for a stationary system. We have modi~Aed our two-dimensional heliosperic cosmic-ray simulation code to be time dependent and to include a propagating shock wave which propagates out from the Sun and into the Heliosheath. The code follows the time variation of the intensity of both galacticand anomalous cosmic rays as the shock propagates past the point of observation and beyond. The results from the model simulations will be compared with recent observational results suggesting e~@ects of the heliosheath on galacticc and anomalous cosmic rays.

Jokipii, J. R.; Kota, J.

2001-08-01

442

Investigation of resonance integrals occurring in cosmic ray diffusion theory  

NASA Technical Reports Server (NTRS)

The method for calculating the pitch angle diffusion coefficient is investigated for cosmic rays in a static random magnetic field, using the resonance integral method. The pitch angle diffusion coefficient may be derived from the Vlasov equation via ensemble averaging.

Jones, F. C.; Birmingham, T. J.; Kaiser, T. B.

1972-01-01

443

Cosmic ray synthesis of organic molecules in Titan's atmosphere  

NASA Technical Reports Server (NTRS)

The possible synthesis of organic molecules by the absorption of galactic cosmic rays in an N2-CH4-H2 Titan model atmosphere has been studied. The cosmic-ray-induced ionization results in peak electron densities of 2000/cu cm, with NH(+), C3H9(+), and C4H9(+) being among the important positive ions. Details of the ion and neutral chemistry relevant to the production of organic molecules are discussed. The potential importance of N(2D) reactions with CH4 and H2 is also demonstrated. Although the integrated production rate of organic matter due to the absorption of the cosmic ray cascade is much less than that by solar ultraviolet radiation, the production of nitrogen-bearing organic molecules by cosmic rays may be greater.

Capone, L. A.; Dubach, J.; Whitten, R. C.; Prasad, S. S.; Santhanam, K.

1980-01-01

444

Separation of the geomagnetic variation of cosmic rays  

NASA Astrophysics Data System (ADS)

The contributions of geomagnetic variations and complex variations in cosmic ray intensities to measured variations in the neutron component of cosmic ray flux are separated by a study of normalized neutron intensities recorded at three stations with different cut-off rigidities. The correlation between Dst variations and temporal variations in normalized intensity differences is calculated for stations with rigidities of 0.0, 4.0 and 13 GV during the large magnetic storm (300 nT) of March 5-13, 1970. Results show the increase in cosmic ray intensities observed during the storm to be due to a decrease in cosmic ray cut-off rigidities. The maximum Dst decrease of 280 nT is found to lead to a 3.2 percent variation in the intensity difference between Dallas and Churchill stations, and a 4.2 percent variation in the difference between Chacataya and Churchill, in agreement with theoretical calculations.

Zhumabaev, B. T.; Kozin, I. D.

445

The cosmic ray muon energy spectum via ?erenkov radiation  

E-print Network

In this thesis, I designed and constructed a basic Cerenkov detector to measure the energy spectrum of cosmic ray muons for use in the graduate experimental physics courses, 8.811/2. The apparatus consists of a light-tight ...

Quintero, Eric Antonio

2010-01-01

446

UNDERSTANDING TeV-BAND COSMIC-RAY ANISOTROPY  

SciTech Connect

We investigate the temporal and spectral correlations between flux and anisotropy fluctuations of TeV-band cosmic rays in light of recent data taken with IceCube. We find that for a conventional distribution of cosmic-ray sources, the dipole anisotropy is higher than observed, even if source discreteness is taken into account. Moreover, even for a shallow distribution of galactic cosmic-ray sources and a reacceleration model, fluctuations arising from source discreteness provide a probability only of the order of 10% that the cosmic-ray anisotropy limits of the recent IceCube analysis are met. This probability estimate is nearly independent of the exact choice of source rate, but generous for a large halo size. The location of the intensity maximum far from the Galactic Center is naturally reproduced.

Pohl, Martin [DESY, D-15738 Zeuthen (Germany)] [DESY, D-15738 Zeuthen (Germany); Eichler, David, E-mail: pohlmadq@gmail.com, E-mail: eichler@bgu.ac.il [Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel)] [Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel)

2013-03-20

447

Cosmic ray lithium isotope measurement with AMS-01  

E-print Network

The AMS-01 detector measured charged cosmic rays during 10 days on the Space Shuttle Discovery in 1998 and collected 108 events. By identifying 8349 Lithium and 22709 Carbon nuclei from the raw data, this thesis presents ...

Zhou, Feng, Ph. D. Massachusetts Institute of Technology

2009-01-01

448

Cosmic Rays and Other Nonsense in Astronom ical CCD Imagers  

E-print Network

Compton­scattered gamma rays, although worms are also produced directly by beta emitters in dewar windows and field lenses. The gamma rays are mostly byproducts of 40 K decay and the U and Th decay chains. Trace and shielding. The cosmic­ray muon rate is irreducible. Our conclusions are supported by tests at the Lawrence