WorldWideScience

Sample records for individual cosmic spherules

  1. Refractory metal nuggets in different types of cosmic spherules.

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M; Plane, J.M; Berg, T.; Feng, W.; Balgar, S.

    from 23 I-, 21 S- and 5 G-type cosmic spherules, respectively. The nuggets in all the three spherule types follow a pattern indicative of their formation by metal segregation during atmospheric entry due to heating and oxidation, however...

  2. Chondrule-like object from the Indian Ocean cosmic spherules

    Indian Academy of Sciences (India)

    K Reshma; N G Rudraswami; M Shyam Prasad

    2013-08-01

    Five hundred and eighteen cosmic spherules were identified among the 672 spherules handpicked from deep sea sediments by using Scanning Electron Microscope-Energy Dispersive Spectrometry (SEM-EDS). One of the spherules is found to enclose a spherical chondrule-like object that can be distinguished from the rest of the spherule by its shape, texture and composition and whose petrographic features, size and chemical composition are similar to chondrules from a chondritic meteorite, probably of carbonaceous chondritic nature. The present finding suggests that a small fraction of the particulate extraterrestrial matter enters the earth as fragments of larger meteorites.

  3. Analysis of Cosmic Spherule Candidates from the Kwajalein Micrometeorite Collection

    Science.gov (United States)

    Wozniakiewicz, P. J.; Price, M. C.; Bradley, J. P.; Ishii, H. A.; Russell, S. S.; Zolensky, M. E.; Brownlee, D. E.

    2015-01-01

    The Kwajalein micrometeorite collection utilised high volume air samplers fitted with 5 micrometer laser-etched polycarbonate membrane filters to capture particles directly from the atmosphere. The filters were changed weekly over several months throughout 2011/12, providing the opportunity to investigate the contemporary flux of micrometeorites. We recently reported the results of our initial survey of cosmic spherule-like particles on several of these filters. We identified three main groups of particle based on bulk compositions: 1. Silicate spherules rich in Mg, Ca and Fe, 2. Silicate spherules rich in Al, Ca, K and/or Na and 3. Fe-rich spherules. Abundances appeared to change over time suggesting links with celestial activity (e.g. meteor showers), however, spherules similar to groups 2 and 3 can be produced by terrestrial and anthropogenic activity (e.g. volcanic microspherules exhibit similar compositions to group 2 spherules and metallic spherules similar to those of group 3 can be formed during fuel combustion). We are now studying the internal structures and chemistries of these spherules and comparing against cosmic spherules identified in other collections to confrim their origins and further contrain the contemporary micrometeorite flux. Particles are being picked, embedded in resin and polished through to reveal their interiors. Here we will describe our ongoing analyses of these particles via SEM. We will also introduce our new collection using this method that is currently being performed in the Antarctic.

  4. Chondrule-like object from the Indian Ocean cosmic spherules

    Digital Repository Service at National Institute of Oceanography (India)

    Reshma, K.; Rudraswami, N.G.; ShyamPrasad, M.

    suggested a chondrule bearing asteroid as the parent body. Recently, Taylor et al. (2011) reported on a spherule that contained chondrule/fragments of chondrule and that constituted nearly <0.05% out of 5682 spherules from South Pole Water Well (SPWW.... This cosmic spherule must have landed on the earth’s surface under the conditions of low entry velocity and low zenith angle without much atmospheric heating as the chondrule boundary and the chemical composition of the chondrule-like object are well preserved...

  5. Vesicle dynamics during the atmospheric entry heating of cosmic spherules

    Science.gov (United States)

    Genge, M. J.

    2017-03-01

    Cosmic spherules are unique igneous objects that form by melting due to gas drag heating during atmospheric entry heating. Vesicles are an important component of many cosmic spherules since they suggest their precursors had finite volatile contents. Vesicle abundances in spherules decrease through the series porphyritic, glassy, barred, to cryptocrystalline spherules. Anomalous hollow spherules, with large off-center vesicles occur in both porphyritic and glassy spheres. Numerical simulation of the dynamic behavior of vesicles during atmospheric flight is presented that indicates vesicles rapidly migrate due to deceleration and separate from nonporphyritic particles. Modest rotation rates of tens of radians s-1 are, however, sufficient to impede loss of vesicles and may explain the presence of small solitary vesicles in barred, cryptocrystalline and glassy spherules. Rapid rotation at spin rates of several thousand radians s-1 are required to concentrate vesicles at the rotational axis and leads to rapid growth by coalescence and either separation or retention depending on the orientation of the rotational axis. Complex rapid rotations that concentrate vesicles in the core of particles are proposed as a mechanism for the formation of hollow spherules. High vesicle contents in porphyritic spherules suggest volatile-rich precursors; however, calculation of volatile retention indicates these have lost >99.9% of volatiles to degassing prior to melting. The formation of hollow spherules, by rapid spin, necessarily implies preatmospheric rotations of several thousand radians s-1. These particles are suggested to represent immature dust, recently released from parent bodies, in which rotations have not been slowed by magnetic damping.

  6. Major and trace element geochemistry of S-type cosmic spherules

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Babu, E.V.S.S.K.; VijayaKumar, T.

    , cryptocrystalline, and glass) of S-type cosmic spherules are investigated with the intent to decipher the parent sources using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry. The S-type cosmic spherules appear to show a...

  7. The parent body controls on cosmic spherule texture: Evidence from the oxygen isotopic compositions of large micrometeorites

    Science.gov (United States)

    van Ginneken, M.; Gattacceca, J.; Rochette, P.; Sonzogni, C.; Alexandre, A.; Vidal, V.; Genge, M. J.

    2017-09-01

    High-precision oxygen isotopic compositions of eighteen large cosmic spherules (>500 μm diameter) from the Atacama Desert, Chile, were determined using IR-laser fluorination - Isotope Ratio Mass spectrometry. The four discrete isotopic groups defined in a previous study on cosmic spherules from the Transantarctic Mountains (Suavet et al., 2010) were identified, confirming their global distribution. Approximately 50% of the studied cosmic spherules are related to carbonaceous chondrites, 38% to ordinary chondrites and 12% to unknown parent bodies. Approximately 90% of barred olivine (BO) cosmic spherules show oxygen isotopic compositions suggesting they are related to carbonaceous chondrites. Similarly, ∼90% porphyritic olivine (Po) cosmic spherules are related to ordinary chondrites and none can be unambiguously related to carbonaceous chondrites. Other textures are related to all potential parent bodies. The data suggests that the textures of cosmic spherules are mainly controlled by the nature of the precursor rather than by the atmospheric entry parameters. We propose that the Po texture may essentially be formed from a coarse-grained precursor having an ordinary chondritic mineralogy and chemistry. Coarse-grained precursors related to carbonaceous chondrites (i.e. chondrules) are likely to either survive atmospheric entry heating or form V-type cosmic spherules. Due to the limited number of submicron nucleation sites after total melting, ordinary chondrite-related coarse-grained precursors that suffer higher peak temperatures will preferentially form cryptocrystalline (Cc) textures instead of BO textures. Conversely, the BO textures would be mostly related to the fine-grained matrices of carbonaceous chondrites due to the wide range of melting temperatures of their constituent mineral phases, allowing the preservation of submicron nucleation sites. Independently of the nature of the precursors, increasing peak temperatures form glassy textures.

  8. In situ oxygen isotope compositions in olivines of different types of cosmic spherules: An assessment of relationships to chondritic particles

    Science.gov (United States)

    Rudraswami, N. G.; Shyam Prasad, M.; Jones, R. H.; Nagashima, K.

    2016-12-01

    Cosmic spherules collected from deep sea sediments of the Indian Ocean having different textures such as scoriaceous (4), relict-bearing (16), porphyritic (35) and barred olivine (2) were investigated for petrography, as well as high precision oxygen isotopic studies on olivine grains using secondary ion mass spectrometry (SIMS). The oxide FeO/MgO ratios of large olivines (>20 μm) in cosmic spherules have low values similar to those seen in the olivines of carbonaceous chondrite chondrules, rather than matching the compositions of matrix. The oxygen isotope compositions of olivines in cosmic spherules have a wide range of δ18O, δ17O and Δ17O values as follows: -9 to 40‰, -13 to 22‰ and -11 to 6‰. Our results suggest that the oxygen isotope compositions of the scoriaceous, relict-bearing, porphyritic and barred spherules show provenance related to the carbonaceous (CM, CV, CO and CR) chondrites. The different types of spherules that has experienced varied atmospheric heating during entry has not significantly altered the Δ17O values. However, one of the relict-bearing spherules with a large relict grain has Δ17O = 5.7‰, suggesting that it is derived from 16O-poor material that is not recognized in the meteorite record. A majority of the spherules have Δ17O ranging from -4 to -2‰, similar to values in chondrules from carbonaceous chondrites, signifying that chondrules of carbonaceous chondrites are the major contributors to the flux of micrometeorites, with an insignificant fraction derived from ordinary chondrites. Furthermore, barred spherule data shows that during atmospheric entry an increase in ∼10‰ of δ18O value surges Δ17O value by ∼1‰.

  9. Unaltered cosmic spherules in a 1.4-Gyr-old sandstone from Finland.

    Science.gov (United States)

    Deutsch, A; Greshake, A; Pesonen, L J; Pihlaja, P

    1998-09-10

    Micrometeorites-submillimetre-sized particles derived from asteroids and comets-occur in significant quantities in deep sea sediments, and the ice sheets of Greenland and Antarctica. The most abundant micrometeorites are cosmic spherules, which contain nickel-rich spinels that were crystallized and oxidized during atmospheric entry, therefore recording the oxygen content in the uppermost atmosphere. But the use of micrometeorites for detecting past changes in the flux of incoming extraterrestrial matter, and as probes of the evolution of the atmosphere, has been hampered by the fact that most objects with depositional ages higher than 0.5 Myr show severe chemical alteration. Here we report the discovery of unaltered cosmic spherules in a 1.4-Gyr-old sandstone (red bed) from Finland. From this we infer that red beds, a common lithology in the Earth's history, may contain substantial unbiased populations of fossil micrometeorites. The study of such populations would allow systematic research on variations in the micrometeorite flux from the early Proterozoic era to recent times (a time span of about 2.5 Gyr), and could help to better constrain the time when the atmospheric oxygen content was raised to its present level.

  10. A Study of Mesoproterozoic Iron Cosmic Micro-spherules from 1.8 Ga and 1.6 Ga Old Strata in the Ming Tombs District, Beijing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Numerous iron cosmic micro-spherules have been discovered from Mesoproterozoic strata including the Changzhougou Formation (1.8 Ga) and the Dahongyu Formation (1.6 Ga) of the Ming Tombs district, Beijing. There are 1 to 30 grains of cosmic spherules per 2 kg of a sandstone sample taken from the bottom of a coarse sandstone bed of the Changzhougou Formation and 56 grains per 3.69 kg of a rock sample from silicified carbonate rocks of the Dahongyu Formation. The surface textures of cosmic spherules analyzed by means of the secondary electron imagery are identical with those reported from references either domestic or abroad. So far the geo-ages of 1.8 Ga and 1.6 Ga of cosmic spherules from the Changzhougou and Dahongyu formations might be older than those reported in the world. Table 1 gives the electron probe analysis data of cosmic spherules for 30 spherule grains and 44 testing points as follows (%): FeO, 80-95; Cr2O3; 0-9.56; NiO, 0-0.78; CoO, 0-0.46;indicating that the Cr2O3 content is higher and FeO content lower in the Changzhougou Formation than in the Dahongyu Formation. The helium isotopic data of cosmic spherules as well as their host rocks vary greatly between the Changzhougou and the Dahongyu formations as shown in Table 2. The data of cosmic spherules of the Changzhougou Formation vs the Dahongyu Formation are 57.5/1.23 in 3He/4He (10-8); and 55.54/809.60 in 4He (10-6cm3STP/g); those of coarse sandstone of the Changzhougou Formation vs silicified carbonate of the Dahongyu Formation are 3.39/2.59 in 3He/4He (10-8) and 4.56/2.34 in 3He (10-6cm3STP/g). The ratio of analytic data of helium isotopes are different for cosmic spherules and their host rocks; for example, the 3He/4He (10-8) values are 16.96 and 0.48, and the 4He(10-6 cm3STP/g) are 12.18 and 345.98 for the Changzhougou and Dahongyu formations respectively. It was reported that the world's oldest micrometeorites had been found in the Meso-Proterozoie Satakunta Formation, Finland. However, the

  11. Chemistry and petrology of Fe-Ni beads from different types of cosmic spherules: Implication for precursors

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Babu, E.V.S.S.K.; VijayaKumar, T.

    ratios. The beads that are PGE-enriched have derived their PGE from the silicate regions into the bead as discussed above. The RME data on beads normalized to CI and Os from S-, G- and I-type spherules are close to chondritic, except in the case.... Physical Properties Fe–Ni beads in I-type spherules are observed to have the largest diameters among all the three types of spherules (Figs. 1–3). The beads are nearly spherical in shape and in a majority of the cases they are eccentric, located close...

  12. Coccidioides Endospores and Spherules Draw Strong Chemotactic, Adhesive, and Phagocytic Responses by Individual Human Neutrophils.

    Directory of Open Access Journals (Sweden)

    Cheng-Yuk Lee

    Full Text Available Coccidioides spp. are dimorphic pathogenic fungi whose parasitic forms cause coccidioidomycosis (Valley fever in mammalian hosts. We use an innovative interdisciplinary approach to analyze one-on-one encounters between human neutrophils and two forms of Coccidioides posadasii. To examine the mechanisms by which the innate immune system coordinates different stages of the host response to fungal pathogens, we dissect the immune-cell response into chemotaxis, adhesion, and phagocytosis. Our single-cell technique reveals a surprisingly strong response by initially quiescent neutrophils to close encounters with C. posadasii, both from a distance (by complement-mediated chemotaxis as well as upon contact (by serum-dependent adhesion and phagocytosis. This response closely resembles neutrophil interactions with Candida albicans and zymosan particles, and is significantly stronger than the neutrophil responses to Cryptococcus neoformans, Aspergillus fumigatus, and Rhizopus oryzae under identical conditions. The vigorous in vitro neutrophil response suggests that C. posadasii evades in vivo recognition by neutrophils through suppression of long-range mobilization and recruitment of the immune cells. This observation elucidates an important paradigm of the recognition of microbes, i.e., that intact immunotaxis comprises an intricate spatiotemporal hierarchy of distinct chemotactic processes. Moreover, in contrast to earlier reports, human neutrophils exhibit vigorous chemotaxis toward, and frustrated phagocytosis of, the large spherules of C. posadasii under physiological-like conditions. Finally, neutrophils from healthy donors and patients with chronic coccidioidomycosis display subtle differences in their responses to antibody-coated beads, even though the patient cells appear to interact normally with C. posadasii endospores.

  13. The origin of black magnetic spherules through a study of their chemical, physical and mineralogieal characteristics

    Directory of Open Access Journals (Sweden)

    M. TAGLIAZUCCA

    1976-06-01

    Full Text Available The origin of black magnetic spherules sampled in air,
    and in ancient and recent marine sediments has been investigated.
    Experiments were performed reproducing in laboratory the same processes undergone by the cosmic dust during its flight through the atmosphere.
    Spherules similar in size, shape, chemical and mineralogieal characteristics to the natural ones have been obtained. It has been tested that hollow spherules can be also produced in the high atmosphere.
    The bubble formed inside some black magnetic spherules by the decrease of solubility of oxygen at the melting point can be sometimes ejected from the rear side of the spherule producing secondary particles less than 10 pim is size.
    The volcanic origin of black magnetic spherules has been excluded.
    In fact ferromagnetic volcanic particulate matter present mineralogic,
    chemical and structural characteristics different from that of black magnetic spherules.
    Also the use of some parameters is suggested to discriminate industrial
    ferromagnetic spherules from black magnetic spherules of extraterrestrial origin.
    Samples from sediments old enough to exclude industrial contamination
    allow to calculate the earth accretion in cosmic dust.

  14. Submegaparsec individual photometric redshift estimation from cosmic web constraints

    Science.gov (United States)

    Aragon-Calvo, M. A.; Weygaert, Rien van de; Jones, Bernard J. T.; Mobasher, Bahram

    2015-11-01

    We present a method, PhotoWeb, for estimating photometric redshifts of individual galaxies, and their equivalent distance, with megaparsec and even submegaparsec accuracy using the cosmic web as a constraint over photo-z estimates. PhotoWeb redshift errors of individual galaxies are of the order of Δz ≃ 0.0007, compared to errors of Δz ≃ 0.02 for current photo-z techniques. The mean redshift error is of the order of Δz ≃ 5 × 10-5-5 × 10-4 compared to mean errors in the range Δz ≃ 0.001-0.01 for the best available photo-z estimates in the literature. Current photo-z techniques produce redshift estimates with large errors due to the poor constraining power the galaxy's spectral energy distribution and projected clustering can provide. The cosmic web, on the other hand, provides the strongest constraints on the position of galaxies. The network of walls, filaments and voids occupy ˜ 10 per centof the volume of the Universe, yet they contain ˜ 95 per centof galaxies. The cosmic web, being a cellular system with well-defined boundaries, defines a restricted set of intermittent positions a galaxy can occupy along a given line of sight. Using the information in the density field computed from spectroscopic redshifts, we can narrow the possible locations of a given galaxy along the line of sight from a single broad probability distribution (from photo-z) to one or a few narrow peaks. Our first results improve previous photo-z errors by more than one order of magnitude allowing submegaparsec errors in some cases. Such accurate estimates for tens of millions of galaxies will allow unprecedented galaxy-Large Scale Structure (LSS) studies. In this work, we apply our technique to the Sloan Digital Sky Survey photo-z galaxy sample and discuss its performance and future improvements.

  15. Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago

    Science.gov (United States)

    Wittke, James H.; Weaver, James C.; Bunch, Ted E.; Kennett, James P.; Kennett, Douglas J.; Moore, Andrew M.T.; Hillman, Gordon C.; Tankersly, Kenneth B.; Goodyear, Albert C.; Moore, Christopher R.; Daniel, I. Randolph; Ray, Jack H.; Lopinot, Neal H.; Ferraro, David; Israde-Alcántara, Isabel; Bischoff, James L.; DeCarli, Paul S.; Hermes, Robert E.; Kloosterman, Johan B.; Revay, Zsolt; Howard, George A.; Kimbel, David R.; Kletetschka, Gunther; Nabelek, Ladislav; Lipo, Carl P.; Sakai, Sachiko; West, Allen; Firestone, Richard B.

    2013-01-01

    Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world’s premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event.

  16. Upper limits on the total cosmic-ray luminosity of individual sources

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, R.C.; De Souza, V. [Instituto de Física de São Carlos, Universidade de São Paulo, São Paulo (Brazil); Supanitsky, A.D., E-mail: rita@ifsc.usp.br, E-mail: vitor@ifsc.usp.br, E-mail: supanitsky@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), CONICET-UBA, Buenos Aires (Argentina)

    2014-07-01

    In this paper, upper limits on the total luminosity of ultra-high-energy cosmic-rays (UHECR) E > 10{sup 18} eV) are determined for five individual sources. The upper limit on the integral flux of GeV--TeV gamma-rays is used to extract the upper limit on the total UHECR luminosity of individual sources. The correlation between upper limit on the integral GeV--TeV gamma-ray flux and upper limit on the UHECR luminosity is established through the cascading process that takes place during propagation of the cosmic rays in the background radiation fields, as explained in reference [1]. Twenty-eight sources measured by FERMI-LAT, VERITAS and MAGIC observatories have been studied. The measured upper limit on the GeV--TeV gamma-ray flux is restrictive enough to allow the calculation of an upper limit on the total UHECR cosmic-ray luminosity of five sources. The upper limit on the UHECR cosmic-ray luminosity of these sources is shown for several assumptions on the emission mechanism. For all studied sources an upper limit on the ultra-high-energy proton luminosity is also set.

  17. Method for preparing hydrous zirconium oxide gels and spherules

    Science.gov (United States)

    Collins, Jack L.

    2003-08-05

    Methods for preparing hydrous zirconium oxide spherules, hydrous zirconium oxide gels such as gel slabs, films, capillary and electrophoresis gels, zirconium monohydrogen phosphate spherules, hydrous zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite sorbent, zirconium monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite, hydrous zirconium oxide fiber materials, zirconium oxide fiber materials, hydrous zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite and spherules of barium zirconate. The hydrous zirconium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process are useful as inorganic ion exchangers, catalysts, getters and ceramics.

  18. Cosmic Dust in Suzhou A-Type Granite

    Institute of Scientific and Technical Information of China (English)

    王尔康; 万玉秋; 朱政; 胡中为; 林承毅; 周剑雄; 倪邦发

    1994-01-01

    A large number of microspherules have been extracted from Suzhou A-type granite bymeans of heavy placer.Both natural surfaces and part sections of 539 microspherules have been observed bySEM.457 microspherules have been determined by EDX,with some of them by EPMA,XRD and INAA.The results suggest these spherules are of ablated cosmic dust.Among them silicate glassy microspheruleshave been highly enriched in REE and other lithophile refractory trace elements,and REE abundance patternfavors a meteoritic origin as a roughly flat distribution.Ringwoodite has been first found in these glassy mi-crospherules.The composition of these iron spherules is similar to those of the ablated cosmic dust from deepsea and polar ice.Some Fe-Ni spherules and spherules composed of troilite have also been found.This isprobably the first report on various types of cosmic dust extracted from granite.

  19. Fractionation and fragmentation of glass cosmic spherules during atmospheric entry

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Babu, E.V.S.S.K.; VijayaKumar, T.; Feng, W.; Plane, J.M.C.

    of these elements during atmospheric entry (Fig. 7). However, the bulk chemical compositions of Al, Ca, Mg, Fe are generally CI-like except for some volatile elements, which rules out an achondritic parent body. Taylor et al. (2007) reported anorthite with low... entry with the exception of the particles having high velocities and low zenith angles (Love and Brownlee, 1991; Vondrak et al., 2008). Larger micrometeorites have undergone ablation leading to siderophile and volatile element depletion, and mass...

  20. Induction of Spherule Formation in Physarum polycephalum by Polyols

    Science.gov (United States)

    Chet, I.; Rusch, H. P.

    1969-01-01

    A method has been developed for inducing spherule formation (spherulation) in the myxomycete Physarum polycephalum by transferring the culture to synthetic medium containing 0.5 m mannitol or other polyols. This morphogenetic process occurred within 12 to 35 hr after the inducer was added. The mature spherules existed as distinct morphogenetic units, in contrast to the clusters of spherules formed during starvation. Ninety per cent of the spherules germinated by 24 hr in synthetic medium. The changes in the synthesis of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein during plasmodial growth, spherulation, and germination of spherules are described. When spherule formation was completed, RNA, protein, and DNA decreased, compared with the values at the beginning of the conversion. The incorporation of 3H-uridine into trichloroacetic acid-insoluble material was different in each of these periods, and this incorporation was sensitive to actinomycin D. The amount of glycogen increased during growth, whereas it decreased during spherulation. 14C-glucose could be taken up by the cells in the presence of the inducer, and mannitol could not replace glucose as a source of energy. The mode of action of mannitol and its mechanism of induction are discussed. Images PMID:5389734

  1. Probing Individual Sources during Reionization and Cosmic Dawn using Square Kilometre Array HI 21-cm Observations

    Indian Academy of Sciences (India)

    Kanan K. Datta; Raghunath Ghara; Suman Majumdar; T. Roy Choudhury; Somnath Bharadwaj; Himadri Roy; Abhirup Datta

    2016-12-01

    Detection of individual luminous sources during the reionization epoch and cosmic dawn through their signatures in the HI 21-cm signal is one of the direct approaches to probe the epoch. Here, we summarize our previous works on this and present preliminary results on the prospects of detecting such sources using the SKA1-low experiment. We first discuss the expected HI 21-cm signal around luminous sources at different stages of reionization and cosmic dawn. We then introduce two visibility based estimators for detecting such signals: one based on the matched filtering technique and the other relies on simply combing the visibility signal from different baselines and frequency channels. We find that the SKA1-low should be able to detect ionized bubbles of radius $R_{\\mathrm {b}} \\gtrsim 10$ Mpc with $\\sim100 \\rm h$ of observations at redshift $z\\sim8$ provided that the mean outside neutral hydrogen fraction $\\mathrm {x}_{\\text {HI}} \\gtrsim 0.5$. We also investigate the possibility of detecting HII regions around known bright QSOs such as around ULASJ1120+0641 discovered by Mortlock et al. (Nature 474, 7353 (2011)). We find that a $5σ$ detection is possible with 600 h of SKA1-low observations if the QSO age and the outside $\\mathrm {x}_{\\text {HI}}$ are at least $\\sim2 \\times 10^7$ Myr and $\\sim0.2$ respectively. Finally, we investigate the possibility of detecting the very first X-ray and Ly- α sources during the cosmic dawn. We consider mini-QSOs like sources which emits in X-ray frequency band. We find that with a total $\\sim 1000 \\rm h$ of observations, SKA1-low should be able to detect those sources individually with a $∼ 9σ$ significance at redshift z=15. We summarize how the SNR changes with various parameters related to the source properties.

  2. Sub-Megaparsec Individual Photometric Redshift Estimation from Cosmic Web Constraints

    CERN Document Server

    Aragon-Calvo, Miguel A; Jones, Bernard J T; Mobasher, Bahram

    2014-01-01

    We present a method, PhotoWeb, for estimating photometric redshifts of individual galaxies, and their equivalent distance, with megaparsec and even sub-megaparsec accuracy using the Cosmic Web as a constraint over photo-z estimates. PhotoWeb redshift errors for individual galaxies are of the order of delta_z = 0.0007, compared to errors of delta_z = 0.02 for current photo-z techniques. The mean redshift error is of the order of 0.00005-0.0004 compared to mean errors in the range delta_z =z 0.001-0.01 for the best available photo-z estimates in the literature. Current photo-z techniques based on the spectral energy distribution of galaxies and projected clustering produce redshift estimates with large errors due to the poor constraining power the galaxy's spectral energy distribution and projected clustering can provide. The Cosmic Web, on the other hand, provides the strongest constraints on the position of galaxies. The network of walls, filaments and voids occupy ~%10 of the volume of the Universe, yet they...

  3. Method for preparing hydrous iron oxide gels and spherules

    Science.gov (United States)

    Collins, Jack L.; Lauf, Robert J.; Anderson, Kimberly K.

    2003-07-29

    The present invention is directed to methods for preparing hydrous iron oxide spherules, hydrous iron oxide gels such as gel slabs, films, capillary and electrophoresis gels, iron monohydrogen phosphate spherules, hydrous iron oxide spherules having suspendable particles homogeneously embedded within to form composite sorbents and catalysts, iron monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent, iron oxide spherules having suspendable particles homogeneously embedded within to form a composite of hydrous iron oxide fiber materials, iron oxide fiber materials, hydrous iron oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, iron oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, dielectric spherules of barium, strontium, and lead ferrites and mixtures thereof, and composite catalytic spherules of barium or strontium ferrite embedded with oxides of Mg, Zn, Pb, Ce and mixtures thereof. These variations of hydrous iron oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters, dielectrics, and ceramics.

  4. Probing individual sources during reionization and cosmic dawn using SKA HI 21-cm observations

    CERN Document Server

    Datta, Kanan K; Majumdar, Suman; Choudhury, T Roy; Bharadwaj, Somnath; Roy, Himadri; Datta, Abhirup

    2016-01-01

    Detection of individual luminous sources during the reionization epoch and cosmic dawn through their signatures in the HI 21-cm signal is one of the direct approaches to probe the epoch. Here, we summarize our previous works on this and present preliminary results on the prospects of detecting such sources using the SKA1-low experiment. We first discuss the expected HI 21-cm signal around luminous sources at different stages of reionization and cosmic dawn. We then introduce two visibility based estimators for detecting such signal: one based on the matched filtering technique and the other relies on simply combing the visibility signal from different baselines and frequency channels. We find that that the SKA1-low should be able to detect ionized bubbles of radius $R_b \\gtrsim 10$ Mpc with $\\sim 100$ hr of observations at redshift $z \\sim 8$ provided that the mean outside neutral Hydrogen fraction $ x_{\\rm HI} \\gtrsim 0.5$. We also investigate the possibility of detecting HII regions around known bright QSOs...

  5. On the angular distribution of cosmic rays from an individual source in a turbulent magnetic field

    CERN Document Server

    Harari, Diego; Roulet, Esteban

    2015-01-01

    We obtain the angular distribution of the cosmic rays reaching an observer from an individual source and after propagation through a turbulent magnetic field, for different ratios between the source distance and the diffusion length. We study both the high-energy quasi-rectilinear regime as well as the transition towards the diffusive regime at lower energies where the deflections become large. We consider the impact of energy losses, showing that they tend to enhance the anisotropy of the source at a given energy. We also discuss lensing effects, in particular those that could result from the regular galactic magnetic field component, and show that the effect of the turbulent extragalactic magnetic fields can smooth out the divergent magnification peaks that would result for point-like sources in the limit of no turbulent deflections.

  6. Serological Comparison of Spherules and Arthrospores of Coccidioides immitis1

    Science.gov (United States)

    Landay, Marshall E.; Wheat, Robert W.; Conant, Norman F.; Lowe, Edwin P.

    1967-01-01

    Spherule and arthrospore cellular preparations were sonic-treated and separated into their respective supernatant and sediment components. Complement-fixation tests with antispherule and antiarthrospore pooled rabbit sera revealed that the soluble antigens exhibited more serological activity than the sediment preparations. After autoclaving, an arthrospore cellular antigen exhibited increased activity with either antisera, whereas autoclaved spherules exhibited increased activity only with antispherule serum. Complement-fixation tests with coccicioidin and spherule culture supernatant preparations revealed quantitative or qualitative differences in antigenic determinants between these two morphological phases of Coccidioides immitis. PMID:6057798

  7. An upper limit on the cosmic-ray luminosity of individual sources from gamma-ray observations

    Energy Technology Data Exchange (ETDEWEB)

    Supanitsky, A.D. [Instituto de Astronomía y Física del Espacio (IAFE), CONICET-UBA (Argentina); Souza, V. de, E-mail: supanitsky@iafe.uba.ar, E-mail: vitor@ifsc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo (Brazil)

    2013-12-01

    Different types of extragalactic objects are known to produce TeV gamma-rays. Some of these objects are the most probable candidates to accelerate cosmic rays up to 10{sup 20} eV. It is very well known that gamma-rays can be produced as a result of the cosmic ray propagation through the intergalactic medium. These gamma-rays contribute to the total flux observed in the direction of the source. In this paper we propose a new method to derive an upper limit on the cosmic-ray luminosity of an individual source based on the measured upper limit on the integral flux of GeV-TeV gamma-rays. We show how it is possible to calculate an upper limit on the cosmic-ray luminosity of a particular source and we explore the parameter space in which the current GeV-TeV gamma-ray measurements can offer a useful determination. We study in detail two particular sources, Pictor A and NGC 7469, and we calculate the upper limit on the proton luminosity of each source based on the upper limit on the integral gamma-ray flux measured by the H.E.S.S. telescopes.

  8. Spherules associated with the cretaceous-paleogene boundary in Poland

    Science.gov (United States)

    Brachaniec, Tomasz; Karwowski, Łukasz; Szopa, Krzysztof

    2014-03-01

    The succession of the Lechówka section near Chełm in south-eastern Poland presents the first complete record of the Cretaceous-Paleogene (K-Pg) boundary in Poland. Samples of the boundary clay were examined for microtektites and shocked minerals to confirm the impact origin of the sediment. The spheroidal fraction reveals morphological and mineralogical features, e.g., spherules, similar to material from the K-Pg boundary as described from elsewhere. The impact genesis of the spherules is confirmed by the presence of nickel-rich spinel grains on their surfaces. The spinels are considered to be primary microlites and, thus, the spherules at Lechówka can be classified as microkrystites. No shocked minerals were noted. The deposits with spherules comprise Aland Mg-rich smectite (Cheto smectite). This almost pure Mg-rich smectite, forming up to 100% of the clay fraction, derived from the weathering of the impact glass. It is proposed that the spherules isolated from the Cretaceous- Paleogene boundary clay at Lechówka come from the Chicxulub crater in Mexico.

  9. Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons

    Energy Technology Data Exchange (ETDEWEB)

    Sedrati, R., E-mail: rafik.sedrati@univ-annaba.org; Attallah, R.

    2014-04-01

    In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (≥10GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data.

  10. Morphological Diversity of the Rod Spherule: A Study of Serially Reconstructed Electron Micrographs.

    Directory of Open Access Journals (Sweden)

    Shuai Li

    Full Text Available Rod spherules are the site of the first synaptic contact in the retina's rod pathway, linking rods to horizontal and bipolar cells. Rod spherules have been described and characterized through electron micrograph (EM and other studies, but their morphological diversity related to retinal circuitry and their intracellular structures have not been quantified. Most rod spherules are connected to their soma by an axon, but spherules of rods on the surface of the Mus musculus outer plexiform layer often lack an axon and have a spherule structure that is morphologically distinct from rod spherules connected to their soma by an axon. Retraction of the rod axon and spherule is often observed in disease processes and aging, and the retracted rod spherule superficially resembles rod spherules lacking an axon. We hypothesized that retracted spherules take on an axonless spherule morphology, which may be easier to maintain in a diseased state. To test our hypothesis, we quantified the spatial organization and subcellular structures of rod spherules with and without axons. We then compared them to the retracted spherules in a disease model, mice that overexpress Dscam (Down syndrome cell adhesion molecule, to gain a better understanding of the rod synapse in health and disease.We reconstructed serial EM images of wild type and DscamGoF (gain of function rod spherules at a resolution of 7 nm in the X-Y axis and 60 nm in the Z axis. Rod spherules with and without axons, and retracted spherules in the DscamGoF retina, were reconstructed. The rod spherule intracellular organelles, the invaginating dendrites of rod bipolar cells and horizontal cell axon tips were also reconstructed for statistical analysis.Stereotypical rod (R1 spherules occupy the outer two-thirds of the outer plexiform layer (OPL, where they present as spherical terminals with large mitochondria. This spherule group is highly uniform and composed more than 90% of the rod spherule population. Rod

  11. The southern stratospheric gravity-wave hot spot: individual waves and their momentum fluxes measured by COSMIC GPS-RO

    Directory of Open Access Journals (Sweden)

    N. P. Hindley

    2015-02-01

    Full Text Available During austral winter the mountains of the southern Andes and Antarctic Peninsula are a known hot spot of intense gravity wave momentum flux. There also exists a long leeward region of increased gravity wave energy that sweeps eastwards from the mountains out over the Southern Ocean, the source of which has historically proved difficult to determine. In this study we use Global Positioning System (GPS Radio Occultation (RO data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC satellite constellation to investigate the distribution, variability and sources of waves in the hot spot region and over the Southern Ocean. We present evidence that suggests a southward focusing of waves into the stratospheric jet from sources to the north. We also describe a wavelet analysis technique for the quantitative identification of individual waves from COSMIC temperature profiles. This analysis reveals different geographical regimes of wave amplitude and short-timescale variability in the wave field over the Southern Ocean. Finally, we take advantage of the large numbers of closely spaced pairs of profiles from the deployment phase of the COSMIC constellation in 2006 to make estimates of gravity wave horizontal wavelengths. We show that, given sufficient numbers of these pairs, GPS-RO can then produce physically reasonable estimates of stratospheric gravity wave momentum flux in the hot spot region that are consistent with other studies. The results are discussed in the context of previous satellite and modelling studies to build up a better picture of the nature and origins of waves in the southern winter stratosphere.

  12. Active Galactic Nuclei - the Physics of Individual Sources and the Cosmic History of Formation and Evolution

    CERN Document Server

    Treister, Ezequiel

    2013-01-01

    In this paper we give a brief review of the astrophysics of active galactic nuclei (AGN). After a general introduction motivating the study of AGNs, we discuss our present understanding of the inner workings of the central engines, most likely accreting black holes with masses between a million and ten billion solar masses. We highlight recent results concerning the jets (collimated outflows) of AGNs derived from X-ray observations (Chandra) of kpc-scale jets and gamma-ray observations of AGNs (Fermi, Cherenkov telescopes) with jets closely aligned with the lines of sight (blazars), and discuss the interpretation of these observations. Subsequently, we summarize our knowledge about the cosmic history of AGN formation and evolution. We conclude with a description of upcoming observational opportunities.

  13. Origin of spherule samples recovered from antarctic ice sheet-Terrestrial or extraterrestrial?

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, Shun; Takamiya, Koichi; Shibata, Seiichi [Research Reactor Institute, Kyoto University, Osaka (Japan); Kobayashi, Takayuki [College of Humanities and Sciences, Nihon University, Tokyo (Japan); Ebihara, Mitsuru [Dept. of Chemistry, Tokyo Metropolitan University, Tokyo (Japan)

    2016-04-15

    Thirty-eight spherules from the Antarctic ice sheet were analyzed using neutron activation analysis under two different conditions to investigate their origin. In almost all of these spherules, the contents of iron, cobalt, and manganese were determined to be 31% to 88%, 17 mg/kg to 810 mg/kg, and 0.017% to 7%, respectively. A detectable iridium content of 0.84 mg/kg was found in only one spherule, which was judged to be extraterrestrial in origin. A comparison of elemental compositions of the Antarctic spherules analyzed in this study with those of deep-sea sediment spherules and those of terrestrial materials revealed that most of the Antarctic spherules except for the sample in which iridium was detected could not be identified as extraterrestrial in origin.

  14. Anthropogenic and impact spherules: Morphological similarity and chemical distinction – A case study from India and its implications

    Indian Academy of Sciences (India)

    Ambalika Niyogi; Jayanta K Pati; Suresh C Patel; Dipak Panda; Shiv K Patil

    2011-12-01

    This paper provides first report of silica-rich anthropogenic spherules of varying colour, shape, size, surface texture and chemical composition found in road-deposited sediments (RDS) of Allahabad city, Uttar Pradesh, India. Morphological details and lithophile elemental composition of the silica-rich spherules are compared to microtektites and impact spherules from India to demonstrate their striking morphological similarities and chemical variability. This study suggests the need to use spherule data carefully while assigning an impact origin to spherule-finds or spherule-bearing lithological horizons.

  15. GOODS-$Herschel$: identification of the individual galaxies responsible for the 80-290$\\mu$m cosmic infrared background

    CERN Document Server

    Leiton, R; Okumura, K; Hwang, H S; Magdis, G; Magnelli, B; Valtchanov, I; Dickinson, M; Béthermin, M; Schreiber, C; Charmandaris, V; Dole, H; Juneau, S; Borgne, D Le; Pannella, M; Pope, A; Popesso, P

    2015-01-01

    We propose a new method of pushing $Herschel$ to its faintest detection limits using universal trends in the redshift evolution of the far infrared over 24$\\mu$m colours in the well-sampled GOODS-North field. An extension to other fields with less multi-wavelength information is presented. This method is applied here to raise the contribution of individually detected $Herschel$ sources to the cosmic infrared background (CIRB) by a factor 5 close to its peak at 250$\\mu$m and more than 3 in the 350$\\mu$m and 500$\\mu$m bands. We produce realistic mock $Herschel$ images of the deep PACS and SPIRE images of the GOODS-North field from the GOODS-$Herschel$ Key Program and use them to quantify the confusion noise at the position of individual sources, i.e., estimate a "local confusion noise". Two methods are used to identify sources with reliable photometric accuracy extracted using 24$\\mu$m prior positions. The clean index (CI), previously defined but validated here with simulations, which measures the presence of b...

  16. Method for preparing hydrous titanium oxide spherules and other gel forms thereof

    Science.gov (United States)

    Collins, J.L.

    1998-10-13

    The present invention are methods for preparing hydrous titanium oxide spherules, hydrous titanium oxide gels such as gel slabs, films, capillary and electrophoresis gels, titanium monohydrogen phosphate spherules, hydrous titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite sorbent, titanium monohydrogen phosphate spherules having suspendible particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, titanium oxide spherules in the form of anatase, brookite or rutile, titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite, hydrous titanium oxide fiber materials, titanium oxide fiber materials, hydrous titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite, titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite and spherules of barium titanate. These variations of hydrous titanium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters and ceramics. 6 figs.

  17. Estimation of occupational cosmic radiation exposure among airline personnel: Agreement between a job-exposure matrix, aggregate, and individual dose estimates.

    Science.gov (United States)

    Talibov, Madar; Salmelin, Raili; Lehtinen-Jacks, Susanna; Auvinen, Anssi

    2017-04-01

    Job-exposure matrices (JEM) are used for exposure assessment in occupational studies, but they can involve errors. We assessed agreement between the Nordic Occupational Cancer Studies JEM (NOCCA-JEM) and aggregate and individual dose estimates for cosmic radiation exposure among Finnish airline personnel. Cumulative cosmic radiation exposure for 5,022 airline crew members was compared between a JEM and aggregate and individual dose estimates. The NOCCA-JEM underestimated individual doses. Intraclass correlation coefficient was 0.37, proportion of agreement 64%, kappa 0.46 compared with individual doses. Higher agreement was achieved with aggregate dose estimates, that is annual medians of individual doses and estimates adjusted for heliocentric potentials. The substantial disagreement between NOCCA-JEM and individual dose estimates of cosmic radiation may lead to exposure misclassification and biased risk estimates in epidemiological studies. Using aggregate data may provide improved estimates. Am. J. Ind. Med. 60:386-393, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Green spherules from Apollo 15 - Inferences about their origin from inert gas measurements.

    Science.gov (United States)

    Lakatos, S.; Yaniv, A.; Heymann, D.

    1973-01-01

    Green spherules from the 'clod' 15426 and from fines 15421 contain about 100 times less trapped inert gases than normal bulk fines from Apollo 15. These spherules have apparently never been directly exposed to the solar wind. Spherules from other fines contain about 10 times more trapped gas than those from the 'clod.' The gas in the former is surface correlated. However, spherules from fines 15401 are exceptionally gas-poor. The trapped gases can be of solar-wind origin, but this origin requires a two-stage model for the spherules from the clods. Another possibility is that the gases were absorbed from an ambient gas phase. The trapped gases may also be assumed to represent primordial lunar gas. The composition of this gas is then similar to the 'solar' or 'unfractionated' component of gas-rich meteorites, but unlike that in most of the carbonaceous chondrites.

  19. Hydrogen Isotopes of Glassy and Phyllosilicate Spherules in Al Rais (CR) and Orgueil (CI) Chondrites

    Institute of Scientific and Technical Information of China (English)

    GUAN Yunbin; Michael E. ZOLENSKY

    2004-01-01

    The hydroxyl in phyllosilicate minerals is the most common occurrence of water in primitive meteorites.Direct hydrogen isotopic analysis of this water component using an ion microprobe has been made in some glassy or phyllosilicate spherules from the Al Rais (CR) and Orgueil (CI) chondrites. The spherules from Al Rais show large deuterium excesses (δD = +200 - +800) relative to terrestrial standards, whereas deuterium-enrichments in the spherules from Orgueil are much smaller (δD = +40 - +130‰). The phyllosilicate spherules are products of aqueous alteration of glassy precursors. In A1 Rais the phyllosilicate spherules have relatively higher δD values than the glassy ones, indicating that water introduced during aqueous alteration was deuterium-enriched. The deuterium-enrichments in the phyllosilicate spherules from Orgueil could result from isotopic exchange under thermodynamic conditions within the solar nebula. The much larger δD excesses of the Al Rais spherules, however, cannot be attributed to the similar process;instead, an interstellar origin needs to be invoked.

  20. Siderophile element fractionation in meteor crater impact glasses and metallic spherules

    Science.gov (United States)

    Mittlefehldt, David W.; See, T. H.; Scott, E. R. D.

    1993-01-01

    Meteor Crater, Arizona provides an opportunity to study, in detail, elemental fractionation processes occurring during impacts through the study of target rocks, meteorite projectile and several types of impact products. We have performed EMPA and INAA on target rocks, two types of impact glass and metallic spherules from Meteor Crater. Using literature data for the well studied Canyon Diablo iron we can show that different siderophite element fractionations affected the impact glasses than affected the metallic spherules. The impact glasses primarily lost Au, while the metallic spherules lost Fe relative to other siderophile elements.

  1. Accretionary Lapilli (Carbonate Spherules) at the Cretaceous-Paleogene ('KT') Boundary in Belize (Central America)

    Science.gov (United States)

    King, D. T.; Petruny, L. W.

    2013-08-01

    The Chicxulub impact event produced accretionary lapilli (or carbonate spherules) that fell across a wide area. This paper compares Chicxulub ('KT') accretionary lapilli from two sites in Belize: Albion Island and Armenia.

  2. Compositional Constraints on Hematite-Rich Spherule (Blueberry) Formation at Meridiani Planum, Mars

    Science.gov (United States)

    Schneider, A. L.; Mittlefehldt, D. W.; Gellert, R.; Jolliff, B.

    2007-01-01

    Meridiani Planum was chosen as the landing site for the Mars Exploration Rover Opportunity partially based on Mars Global Surveyor Thermal Emission Spectrometer data indicating an abundance of hematite. Hematite often forms through processes that involve water, so the site was a promising one to determine whether conditions on Mars were ever suitable for life. Opportunity struck pay dirt; it s Miniature Thermal Emission Spectrometer (Mini-TES) and Mossbauer Spectrometer (MB) confirmed the presence of hematite in sulfate-rich sedimentary beds and in lag deposits. Meridiani Planum rocks contain three main components: silicate phases, sulfate and possibly chloride salts, and ferric oxide phases such as hematite. Primary igneous phases are at low abundance despite the basaltic origin of the protoliths. Jarosite, an alkali ferric sulfate, was identified by Mossbauer. Some of the hematite is contained in the spherules, and some resides in finer grains in outcrops. Mossbauer and Mini-TES data indicate that hematite is a dominant constituent of the spherules. Panoramic Camera (Pancam) and Microscopic Imager (MI) images of spherule interiors show that hematite is present throughout. The exact composition of the spherules is unknown. Mini-TES only identifies a hematite signature in the spherules; any other constituents have an upper limit of 5-10% .The MB data are consistent with the spherules being composed of only hematite.

  3. Oxygen isotopic composition of relict olivine grains in cosmic spherules: Links to chondrules from carbonaceous chondrites

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Nagashima, K.; Jones, R.H.

    evidence of evolved asteroids, similar to chondritic or achondritic parent bodies (e.g., Taylor et al., 2007; Genge et al., 2008; Gounelle et al., 2009; Badjukov et al., 2010; Cordier et al., 2011a, b, 2012; Suavet et al., 2010; Van Ginneken et al., 2012... is much less (Taylor et al., 2000; Yada et al., 2004; Prasad et al., 2013). They are expected to have sampled a wide variety of parent bodies, including those known to us through meteorite studies, and some that have not yet been sampled (Brownlee...

  4. Fremdlinge type object in a cosmic spherule from the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.

    : rudra@nio.org), 2 Department of Earth and Planetary Sci- ences, University of New Mexico, Albuquerque, NM 87131, USA. Introduction: A predominant majority of ~40,000 tons per an- num flux of extraterrestrial matter [1–3] comprises of material...

  5. Numbers, Types and Compositions of an Unbiased Collection of Cosmic Spherules

    Science.gov (United States)

    2000-01-01

    or concentration Age Size range O m ) Deep-sea spheres (DSS) Red clays 0.1 g  000 years all Greenland spheres (GS) Cryoconite, meltwater 2.5 x...34 suctioned from cryoconite holes and the bottom of melt-water streams formed on the Greenland icecap. These particles were well preserved compared...deposits (-3000 years) and contributing ice volume were estimated from an ice-flow model. Following success in Greenland , Maurette et al. (1991) obtained

  6. Isolation and Characterization of a Galactosamine Wall from Spores and Spherules of Physarum polycephalum

    Science.gov (United States)

    McCormick, J. Justin; Blomquist, Judith C.; Rusch, Harold P.

    1970-01-01

    The myxomycete, Physarum polycephalum, can be induced under laboratory conditions to form two different hard-walled forms, spores and spherules. Characterization of both types of walls revealed only a single sugar, galactosamine. It was identified after acid hydrolysis of the isolated walls by chromatography in three solvent systems, by its positive reaction with ammoniacal silver nitrate, ninhydrin, Galactostat, and the Elson-Morgan test, and by ninhydrin degradation to lyxose. Galactosamine was present as a polymer with solubility characteristics the same as the β1-4–linked glucosamine polymer (chitosan). The walls were also found to contain about 2% protein. Spherule walls revealed a single glycoprotein on gel electrophoresis. Spore walls contained a similar protein component. The phosphate content of isolated spherule walls was 9.8%, and that of spore walls was 1.4%. Spore walls also contained about 15% melanin which was shown to be similar to fungal melanin. A novel method was used to measure the rate of mature spherule formation based on the loss of extractability of P. polycephalum natural pigment. The presence of a rare galactosamine polymer in P. polycephalum spore and spherule walls as the only carbohydrate suggests that the myxomycetes are not closely related to the fungi or the protozoa. PMID:16559084

  7. Hematite spherules at Meridiani: results from MI, Mini-TES, and Pancam

    Science.gov (United States)

    Calvin, W.M.; Shoffner, J.D.; Johnson, J. R.; Knoll, A.H.; Pocock, J.M.; Squyres, S. W.; Weitz, C.M.; Arvidson, R. E.; Bell, J.F.; Christensen, P.R.; de Souza, P. A.; Farrand, W. H.; Glotch, T.D.; Herkenhoff, K. E.; Jolliff, B.L.; Knudson, A.T.; McLennan, S.M.; Rogers, A.D.; Thompson, S.D.

    2008-01-01

    We report on observations of hematite-bearing spherules at Meridiani Planum made using the Microscopic Imager (MI), Mini-Thermal Emission Spectrometer (Mini-TES), and Panoramic Camera (Pancam) instruments on the Mars Exploration Rover Opportunity. Spherules were observed on soil surfaces and in outcrop rocks, both on undisturbed surfaces and in abraded surfaces ground using the Rock Abrasion Tool (RAT). Spherule size and shape change little along the 850 m eastward traverse from Eagle Crater to Endurance Crater, but spherules decrease and then slightly increase in size along the 6 km traverse from Endurance south to Victoria Crater. Local populations range from submillimeters to several millimeters in diameter. An additional small diameter (100 μm) size population is possible. An increase in irregular shapes is found near Victoria Crater. This, combined with the size decrease south of Endurance, suggests either a changing depositional environment, or variation in the duration and timing of diagenetic events. The dominant smaller size population observed early in the mission in aeolian areas and ripple crests is observed as the primary size population in abraded outcrop farther south. This suggests that successively younger beds are exposed at the surface along the southward traverse. Stratigraphically higher units removed by erosion could be recorded by the present surface lag deposit. Coordinated systematic observations are used to determine optical and infrared hematite indices of the surface soils in Pancam and Mini-TES. In spite of the systematic variation seen in MI, both Pancam and Mini-TES indices are highly variable based on the local surface, and neither show systematic trends south of Endurance. The lack of a 390 cm?1 feature in Mini-TES spectra suggests concentric or radial interior structure within the spherules at scales too fine for MI to observe. Mini-TES does not detect any silicate component in the spherules. A bound water component in soils or in

  8. Origin and provenance of spherules and magnetic grains at the Younger Dryas boundary

    Science.gov (United States)

    Wu, Yingzhe; Sharma, Mukul; LeCompte, Malcolm A.; Demitroff, Mark N.; Landis, Joshua D.

    2013-09-01

    One or more bolide impacts are hypothesized to have triggered the Younger Dryas cooling at ∼12.9 ka. In support of this hypothesis, varying peak abundances of magnetic grains with iridium and magnetic microspherules have been reported at the Younger Dryas boundary (YDB). We show that bulk sediment and/or magnetic grains/microspherules collected from the YDB sites in Arizona, Michigan, New Mexico, New Jersey, and Ohio have 187Os/188Os ratios ≥1.0, similar to average upper continental crust (= 1.3), indicating a terrestrial origin of osmium (Os) in these samples. In contrast, bulk sediments from YDB sites in Belgium and Pennsylvania exhibit 187Os/188Os ratios meteoritic contribution. The YDB site in Pennsylvania is remarkable in yielding 2- to 5-mm diameter spherules containing minerals such as suessite (Fe-Ni silicide) that form at temperatures in excess of 2000 °C. Gross texture, mineralogy, and age of the spherules appear consistent with their formation as ejecta from an impact 12.9 ka ago. The 187Os/188Os ratios of the spherules and their leachates are often low, but Os in these objects is likely terrestrially derived. The rare earth element patterns and Sr and Nd isotopes of the spherules indicate that their source lies in 1.5-Ga Quebecia terrain in the Grenville Province of northeastern North America.

  9. Spherule layers, crater scaling laws, and the population of ancient terrestrial impactors

    Science.gov (United States)

    Johnson, Brandon C.; Collins, Gareth S.; Minton, David A.; Bowling, Timothy J.; Simonson, Bruce M.; Zuber, Maria T.

    2016-06-01

    Ancient layers of impact spherules provide a record of Earth's early bombardment history. Here, we compare different bombardment histories to the spherule layer record and show that 3.2-3.5 Ga the flux of large impactors (10-100 km in diameter) was likely 20-40 times higher than today. The E-belt model of early Solar System dynamics suggests that an increased impactor flux during the Archean is the result of the destabilization of an inward extension of the main asteroid belt (Bottke et al., 2012). Here, we find that the nominal flux predicted by the E-belt model is 7-19 times too low to explain the spherule layer record. Moreover, rather than making most lunar basins younger than 4.1 Gyr old, the nominal E-belt model, coupled with a corrected crater diameter scaling law, only produces two lunar basins larger than 300 km in diameter. We also show that the spherule layer record when coupled with the lunar cratering record and careful consideration of crater scaling laws can constrain the size distribution of ancient terrestrial impactors. The preferred population is main-belt-like up to ∼50 km in diameter transitioning to a steep distribution going to larger sizes.

  10. Cosmic Strings

    CERN Document Server

    Vachaspati, Tanmay; Steer, Daniele

    2015-01-01

    This article, written for Scolarpedia, provides a brief introduction into the subject of cosmic strings, together with a review of their main properties, cosmological evolution and observational signatures.

  11. Cosmic Magnification

    CERN Document Server

    Ménard, B

    2002-01-01

    I present the current status of the cosmic magnification produced by systematic amplification of background sources by large-scale structures. After introducing its principle, I focus on its interests for cosmology and underline its complementary aspect to cosmic shear and galaxy auto-correlations. I finally discuss recent investigations using higher-order statistics.

  12. Cosmic superstrings.

    Science.gov (United States)

    Sakellariadou, Mairi

    2008-08-28

    Cosmic superstrings are expected to be formed at the end of brane inflation, within the context of brane-world cosmological models inspired from string theory. By studying the properties of cosmic superstring networks and comparing their phenomenological consequences against observational data, we aim to pin down the successful and natural inflationary model and get an insight into the stringy description of our Universe.

  13. Impact glass spherules in the Chicxulub K-Pg event bed at Beloc, Haiti: Alteration patterns

    Science.gov (United States)

    Ritter, Xenia; Deutsch, Alexander; Berndt, Jasper; Robin, Eric

    2015-03-01

    We have investigated six impact glass spherules from the K-Pg event bed at Beloc, Haiti, using optical and electron microscopy, electron microprobe and in situ laser ablation-mass spectrometry (LA-ICP-MS; 37 trace elements, spot size 90-35 μm), in order to understand geochemical changes during alteration. The mm-sized glass spherules are partly or totally altered to smectite, but original textural features are preserved. The average trace-element composition of glass matches that one of the upper continental crust. Hints for a "meteoritic component" are lacking (Ni/Cr < 1.3 Pt below detection limit). Compared to this fresh glass, smectites are strongly depleted in trace elements, except for Li, Sc, V, Ni, Ga, Ge, and Ba. The chondrite-normalized REE distribution patterns are flat with subchondritic abundances, related to their very low degree of crystallinity. We observe a positive Eu and a strong negative Ce anomaly; the latter is explained by formation of an organic Ce4+-complex, soluble under reducing conditions. Zr/Hf of glasses and smectites is chondritic to superchondritic (35-40), whereas Nb/Ta in smectite is subchondritic (5-12) compared to Nb/Ta in the glass (~14-18). The low Nb/Ta is due to the low Nb concentrations in the smectite. Using in situ techniques with high spatial resolution, we have documented for the first time the significant changes in diagnostic elemental ratios during alteration of glass spherules. This has to be taken into account in the interpretation of geochemical data of not only impact materials but also volcanic glass, especially if bulk rock methods are used.

  14. Investigating the Present Day Cosmic Dust Flux at the Earth's Surface: Initial Results from the Kwajalein Micrometeorite Collection

    Science.gov (United States)

    Wozniakiewicz, P. J.; Bradley, J. P.; Price, M. C.; Zolensky, M. E.; Ishii, H. A.; Brownlee, D. E.; Russell, S. S.

    2014-01-01

    Examination of impact craters on the Long Duration Exposure Facility satellite indicate a present day micrometeoroid flux of approx. 30,000 tonnes [1 after 2]. But what portion of this material arrives at the Earth's surface as micrometeorites? Studies of available micrometeorite collections from deep sea sediments [e.g. 3], Greenland blue ice [e.g. 4] and the South Pole water well [e.g. 1] may be complicated by terrestrial weathering and, in some cases, collection bias (magnetic separation for deep sea sediments) and poorly constrained ages. We have recently set up a micrometeorite collection station on Kwajalein Island in the Republic of the Marshall Islands in the Pacific Ocean, using high volume air samplers to collect particles directly from the atmosphere. By collecting in this way, the terrestrial age of the particles is known, the weathering they experience is minimal, and we are able to constrain particle arrival times. Collecting at this location also exploits the considerably reduced anthropogenic background [5]. Method: High volume air samplers were installed on top of the two-story airport building on Kwajalein. These were fitted with polycarbonate membrane filters with 5µm diameter perforations. The flow rates were set to 0.5m3/min, and filters were changed once a week. After collection, filters were washed to remove salt and concentrate particles [see 5] in preparation for analysis by SEM. Results and Discussion: A selection of filters have been prepared and surveyed. Due to their ease of identification our initial investigations have focused on particles resembling cosmic spherules. The spheres can be divided into three main groups: 1. Silicate spherules rich in Al, Ca, K and Na (to varying degrees), 2. Silicate spherules rich in Mg and Fe and 3. Fe-rich spherules. Group 1 spherules are often vesiculated and can occur as aggregates. They are similar in appearance and composition to volcanic microspheres [e.g. 6] and are thus likely terrestrial in

  15. In situ oxygen isotope compositions in olivines of different types of cosmic spherules: An assessment of relationships to chondritic particles

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Jones, R.H.; Nagashima, K.

    et al., 2015a). The micrometeorites that have entered Earth’s atmosphere at high zenith angle and low velocity are interesting because their petrologic and isotopic characteristics are largely preserved thereby providing constraints on the parent... et al., 2012). Oxygen isotope studies complemented by mineralogical compositions are vital to unravel the complexity involved in distinguishing the known components of micrometeorites and their parent bodies. For carbonaceous chondrites...

  16. Cosmic Forms

    CERN Document Server

    Kleman, Maurice

    2011-01-01

    The continuous 1D defects of an isotropic homogeneous material in an Euclidean 3D space are classified by a construction method, the Volterra process (VP). We employ the same method to classify the continuous 2D defects (which we call \\textit{cosmic forms}) of a vacuum in a 4D maximally symmetric spacetime. These defects fall into three different classes: i)- $m$-forms, akin to 3D space disclinations, related to ordinary rotations and analogous to Kibble's global cosmic strings (except that being continuous any deficit angle is allowed); ii)- $t$-forms, related to Lorentz boosts (hyperbolic rotations); iii)- $r$-forms, never been considered so far, related to null rotations. A detailed account of their metrics is presented. Their inner structure in many cases appears as a non-singular \\textit{core} separated from the outer part by a timelike hypersurface with distributional curvature and/or torsion, yielding new types of geometrical interactions with cosmic dislocations and other cosmic disclinations. Whereas...

  17. Cosmic confusion

    CERN Document Server

    Magueijo, J

    1994-01-01

    We propose to minimise the cosmic confusion between Gaussian and non Gaussian theories by investigating the structure in the m's for each multipole of the cosmic radiation temperature anisotropies. We prove that Gaussian theories are (nearly) the only theories which treat all the m's equally. Hence we introduce a set of invariant measures of ``m-preference'' to be seen as non-Gaussianity indicators. We then derive the distribution function for the quadrupole ``m-preference'' measure in Gaussian theories. A class of physically motivated toy non Gaussian theories is introduced as an example. We show how the quadrupole m-structure is crucial in reducing the confusion between these theories and Gaussian theories.

  18. Cosmic Ether

    CERN Document Server

    Tomaschitz, R

    1998-01-01

    A prerelativistic approach to particle dynamics is explored in an expanding Robertson-Walker cosmology. The receding galactic background provides a distinguished frame of reference and a unique cosmic time. In this context the relativistic, purely geometric space-time concept is criticized. Physical space is regarded as a permeable medium, the cosmic ether, which effects the world-lines of particles and rays. We study in detail a Robertson-Walker universe with linear expansion factor and negatively curved, open three-space; we choose the permeability tensor of the ether in such a way that the semiclassical approximation is exact. Galactic red-shifts depend on the refractive index of the ether. In the local Minkowskian limit the ether causes a time variation of mass, which scales inversely proportional to cosmic time. In the globally geodesic rest frames of galactic observers the ether manifests itself in an unbounded speed of signal transfer, in bifurcations of world-lines, and in time inversion effects.

  19. Cosmic radioactivities

    CERN Document Server

    Arnould, M; Arnould, Marcel; Prantzos, Nikos

    1999-01-01

    Radionuclides with half-lives ranging from some years to billions of years presumably synthesized outside of the solar system are now recorded in ``live'' or ``fossil'' form in various types of materials, like meteorites or the galactic cosmic rays. They bring specific astrophysical messages the deciphering of which is briefly reviewed here, with special emphasis on the contribution of Dave Schramm and his collaborators to this exciting field of research. Short-lived radionuclides are also present in the Universe today, as directly testified by the gamma-ray lines emitted by the de-excitation of their daughter products. A short review of recent developments in this field is also presented.

  20. Cosmic radioactivities

    Science.gov (United States)

    Arnould, Marcel; Prantzos, Nikos

    1999-07-01

    Radionuclides with half-lives ranging from some years to billions of years presumably synthesized outside of the solar system are now recorded in "live" or "fossil" form in various types of materials, like meteorites or the galactic cosmic rays. They bring specific astrophysical messages, the deciphering of which is briefly reviewed here, with special emphasis on the contribution of Dave Schramm and his collaborators to this exciting field of research. Short-lived radionuclides are also present in the Universe today, as directly testified by the γ-ray lines emitted by the de-excitation of their daughter products. A short review of recent developments in this field is also presented.

  1. Micro-XRF Analysis of Archean Spherule Layers and Host Rocks from the CT3 Drill Core, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Hoehnel, D.; Tagle, R.; Hofmann, A.; Reimold, W. U.; Mohr-Westheide, T.; Fritz, J.; Altenberger, U.

    2016-08-01

    Spherule layers and host rock samples from the Barberton Greenstone Belt were studied with a µ-XRF spectrometer. Elemental distribution maps indicate distinct folding that had been recognized neither by visual inspection nor by petrographic analysis.

  2. Nondestructive spectroscopic and petrochemical investigations of Paleoarchean spherule layers from the ICDP drill core BARB5, Barberton Mountain Land, South Africa

    Science.gov (United States)

    Fritz, Jörg; Tagle, Roald; Ashworth, Luisa; Schmitt, Ralf Thomas; Hofmann, Axel; Luais, Béatrice; Harris, Phillip D.; Hoehnel, Desirée; Özdemir, Seda; Mohr-Westheide, Tanja; Koeberl, Christian

    2016-12-01

    A Paleoarchean impact spherule-bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro-X-ray fluorescence (μXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer-scale, assisted in the localization and characterization of eight spherule-bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The μXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni-Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3-rich and can be distinguished from the Al2O3-poor marine sediments by distinct Al-OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al-OH-rich spherule layers in Al2O3-poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism.

  3. Compositional Grading in an Impact-produced Spherule Bed, Barberton Greenstone Belt, South Africa: A Key to Condensation History of Rock Vapor Clouds

    Science.gov (United States)

    Krull, A. E.; Lowe, D. R.; Byerly, G. R.

    2003-01-01

    The chemical and physical processes by which spherules form during the condensation of impact-produced rock vapor clouds are poorly understood. Although efforts have been made to model the processes of spherule formation, there is presently a paucity of field data to constrain the resulting theoretical models. The present study examines the vertical compositional variability in a single early Archean spherule bed in the Barberton Greenstone Belt (BGB), South Africa, in order to better identify the process by which impact vapor clouds condense and spherules form and accumulate. The BGB spherule beds are suitable for this type of study because of their great thickness, often exceeding 25cm of pure spherules, due to the massive sizes of the impactors. Two main problems complicate analysis of vertical compositional variability of graded spherule beds: (1) differential settling of particles in both the vapor and water column due to density and size differences and (2) turbulence within the vapor cloud. The present study compares sections of spherule bed S3 from four different depositional environments in the Barberton Greenstone Belt: (1) The Sheba Mine section (SAF-381) was deposited under fairly low energy conditions in deep water, providing a nice fallout sequence, and also has abundant Ni-rich spinels; (2) Jay's Chert section (SAF-380) was deposited in subaerial to shallow-water conditions with extensive post-depositional reworking by currents. The spherules also have preserved spinels; (3) the Loop Road section (loc. SAF-295; samp. KSA-7) was moderately reworked and has only rare preservation of spinels; and (4) the shallow-water Barite Syncline section (loc. SAF-206; samp KSA-1) has few to no spinels preserved and is not reworked. Although all of the spherule beds have been altered by silica diagenesis and K-metasomatism, most of the compositional differences between these sections appear to reflect their diagenetic histories, possibly related to their differing

  4. New insights from old spherules: Os-W isotope and HSE evidence for Paleoarchean meteorite bombardment of the Earth

    Science.gov (United States)

    Schulz, T.; Luguet, A. A.; Koeberl, C.

    2014-12-01

    Introduction: Although still debated, spherule beds in the Barberton Mountain Land (~3.4 Ga) are suspected to represent remnants of impact-generated and ballistically emplaced silicate melt droplets [e.g. 1]. Such deposits provide the only window into the late stages of the heavy meteorite bombardment on Earth as their source craters have long since been obliterated. In order to identify a possible meteoritic component and, if successful, to discuss potential projectile materials, we are performing a detailed Os-W isotope as well as HSE abundance study on spherule layers from the recently drilled ICDP BARB5 core (grid location 25°30`50.76``S, 31°33`10.08``E). Samples and Methods: Samples were taken from a spherule-containing meta-sedimentary core section discovered between 510 and 512 m depth. About 100 mg of homogenized sample powders were spiked with a mixed 190Os, 185Re, 191Ir and 194Pt tracer and treated in a high pressure asher using inverse aqua regia, followed by conventional extraction schemes for Os and the other HSEs [4]. Chemical and Os isotope measurements (via N-TIMS) were performed in Vienna, whereas HSE measurements were undertaken via ICP MS in Bonn. Results and Discussion: Our preliminary Os isotope data reveal a trend between samples exhibiting high spherule to matrix ratios (187Os/188Os ~0.106 and Os ~0.4 ppm) and samples with lower ones (187Os/188Os up to ~0.304 and Os ~0.008 ppm). Notably, the most unradiogenic samples exhibit carbonaceous-chondrite-like initial 187Os/188Os and HSE ratios, whereas all other samples are clear non-chondritic. These findings support an extraterrestrial contribution in the spherules and can be interpreted compared to conclusions drawn from a Cr isotope study performed on similar samples [3], possibly representing a different impact event and favouring a chondritic projectile. However, further considerations based on precise Os/W ratio determinations and high-precision 182W isotope data, will be presented at the

  5. Primordial anisotropies from cosmic strings during inflation

    Science.gov (United States)

    Jazayeri, Sadra; Sadr, Alireza Vafaei; Firouzjahi, Hassan

    2017-07-01

    In this work, we study the imprint of an individual primordial cosmic string within a Hubble patch on the inflationary power spectrum. A straight cosmic string induces two distinct contributions to the curvature perturbations power spectrum. The first type of correction respects the translation invariance while violating isotropy. This generates quadrupolar statistical anisotropy in cosmic microwave background maps, which is constrained by the Planck data. The second contribution breaks both homogeneity and isotropy, generating a dipolar power asymmetry in the variance of temperature fluctuations with its amplitude falling on small scales. We show that the strongest constraint on the tension of primordial cosmic strings is obtained from the quadrupolar anisotropy and argue that the mass scale of the underlying theory responsible for the formation of the string cannot be much higher than the grand unified theory scale. The predictions for the diagonal and off-diagonal components of the cosmic microwave background angular power spectrum induced by the string are presented.

  6. ALICE Cosmic Ray Detector

    CERN Multimedia

    Fernandez Tellez, A; Martinez Hernandez, M; Rodriguez Cahuantzi, M

    2013-01-01

    The ALICE underground cavern provides an ideal place for the detection of high energy atmospheric muons coming from cosmic ray showers. ACORDE detects cosmic ray showers by triggering the arrival of muons to the top of the ALICE magnet.

  7. Cosmic rays on earth.

    Science.gov (United States)

    Allkofer, O. C.; Grieder, P. K. F.

    Contents: Cosmic rays in the atmosphere: Charged hadron data. Neutron data. Gamma-ray data. Electron data. Muon data. Data on nuclei. Data on antiparticles. Cosmic rays at sea level: Muon data. Charged hadron data.Neutron data. Electron data. Gamma-ray data. Data on nuclei. Cosmic rays underground: Muon data. Neutrino data.

  8. The Cosmic DUNE dust astronomy mission

    Science.gov (United States)

    Grun, E.; Srama, R.; Cosmic Dune Team

    A dust astronomy mission aims at the simultaneous measurement of the origin and the chemical composition of individual dust grains in space. Interstellar dust traversing the solar system constitutes the galactic solid phase of matter from which stars and planetary systems form. Interplanetary dust, from comets and asteroids, represents remnant material from bodies at different stages of early solar system evolution. Thus, studies of interstellar and interplanetary dust with Cosmic DUNE (Cosmic Dust Near Earth) will provide a comparison between the composition of the interstellar medium and primitive planetary objects. Cosmic DUNE will prepare the way for effective collection in near-Earth space of interstellar and interplanetary dust for subsequent return to Earth and analysis in laboratories. Cosmic DUNE establishes the next logical step beyond NASA's Stardust mission, with four major advancements in cosmic dust research: (1) Analysis of the elemental and isotopic composition of individual cosmic dust grains, (2) determination of the size distribution of interstellar dust, (3) characterization of the interstellar dust flow through the planetary system, and (4) analysis of interplanetary dust of cometary and asteroidal origin. This mission goal will be reached with novel dust instrumentation. A dust telescope trajectory sensor has been developed which is capable of obtaining precision trajectories of sub-micron sized particles in space. A new high mass resolution dust analyzer of 0.1m2 impact area can cope with the low fluxes expected in interplanetary space. Cosmic DUNE will be proposed to ESA in response to its upcoming call for mission ideas.

  9. Cosmic Complexity

    Science.gov (United States)

    Mather, John C.

    2012-01-01

    neutrons, liberating a little energy and creating complexity. Then, the expanding universe cooled some more, and neutrons and protons, no longer kept apart by immense temperatures, found themselves unstable and formed helium nuclei. Then, a little more cooling, and atomic nuclei and electrons were no longer kept apart, and the universe became transparent. Then a little more cooling, and the next instability began: gravitation pulled matter together across cosmic distances to form stars and galaxies. This instability is described as a "negative heat capadty" in which extracting energy from a gravitating system makes it hotter -- clearly the 2nd law of thermodynamics does not apply here! (This is the physicist's part of the answer to e e cummings' question: what is the wonder that's keeping the stars apart?) Then, the next instability is that hydrogen and helium nuclei can fuse together to release energy and make stars burn for billions of years. And then at the end of the fuel source, stars become unstable and explode and liberate the chemical elements back into space. And because of that, on planets like Earth, sustained energy flows support the development of additional instabilities and all kinds of complex patterns. Gravitational instability pulls the densest materials into the core of the Earth, leaving a thin skin of water and air, and makes the interior churn incessantly as heat flows outwards. And the heat from the sun, received mostly near the equator and flowing towards the poles, supports the complex atmospheric and oceanic circulations. And because or that, the physical Earth is full of natural chemical laboratories, concentrating elements here, mixing them there, raising and lowering temperatures, ceaselessly experimenting with uncountable events where new instabilities can arise. At least one of them was the new experiment called life. Now that we know that there are at least as many planets as there are stars, it is hard to imagine that nature's ceasess

  10. Cosmic Complexity

    Science.gov (United States)

    Mather, John C.

    2012-01-01

    neutrons, liberating a little energy and creating complexity. Then, the expanding universe cooled some more, and neutrons and protons, no longer kept apart by immense temperatures, found themselves unstable and formed helium nuclei. Then, a little more cooling, and atomic nuclei and electrons were no longer kept apart, and the universe became transparent. Then a little more cooling, and the next instability began: gravitation pulled matter together across cosmic distances to form stars and galaxies. This instability is described as a "negative heat capadty" in which extracting energy from a gravitating system makes it hotter -- clearly the 2nd law of thermodynamics does not apply here! (This is the physicist's part of the answer to e e cummings' question: what is the wonder that's keeping the stars apart?) Then, the next instability is that hydrogen and helium nuclei can fuse together to release energy and make stars burn for billions of years. And then at the end of the fuel source, stars become unstable and explode and liberate the chemical elements back into space. And because of that, on planets like Earth, sustained energy flows support the development of additional instabilities and all kinds of complex patterns. Gravitational instability pulls the densest materials into the core of the Earth, leaving a thin skin of water and air, and makes the interior churn incessantly as heat flows outwards. And the heat from the sun, received mostly near the equator and flowing towards the poles, supports the complex atmospheric and oceanic circulations. And because or that, the physical Earth is full of natural chemical laboratories, concentrating elements here, mixing them there, raising and lowering temperatures, ceaselessly experimenting with uncountable events where new instabilities can arise. At least one of them was the new experiment called life. Now that we know that there are at least as many planets as there are stars, it is hard to imagine that nature's ceasess

  11. Experimental evidence for the global acidification of surface ocean at the Cretaceous-Palaeogene boundary: the biogenic calcite-poor spherule layers

    Science.gov (United States)

    Premović, Pavle I.

    2009-07-01

    The massive amount of impact-generated atmospheric CO2 at the Cretaceous-Palaeogene boundary (KPB) would have accumulated globally in the surface ocean, leading to acidification and CaCO3 undersaturation. These chemical changes would have caused a crisis of biocalcification of calcareous plankton and enhanced dissolution of their shells; these factors together may have played a crucial role in forming the biogenic calcite-poor KPB spherule layers observed at numerous oceanic sites and marine (now on land) sites in Europe and Africa. Experimental data and observations indicate that the deposition spherule layer probably lasted only a few decades at most.

  12. Production profiles of nuclides by galactic-cosmic-ray particles in small meteoroids

    Science.gov (United States)

    Reedy, R. C.; Masarik, J.

    Many of the meteorites found in cold and hot deserts are small, and many were small bodies in space. Production of cosmic-ray-produced (cosmogenic) nuclides in small meteoroids is expected to be different than that in the larger meteoroids typically studied, with lower levels of nuclide production by galactic-cosmic-ray (GCR) particles and possibly significant production by solar-cosmic-ray (SCR) protons. Motivated by the cosmogenic-nuclide measurements for the very small Salem meteorite and for cosmic spherules, which show high levels of SCR production, we have reported earlier nuclide production rates by SCR protons in small objects in space. The GCR production rates reported for small meteoroids have not been tested and were expected to be poor for meteoroids with radii less than 40 g/cm2 because of the very simple nature of that semi-empirical model (only one free parameter) and because the mix of neutrons and protons is different (relatively more protons) than that in the model, which was based on larger objects. Thus we have calculated produciton rates for nuclides mad by GCR particles in small objects with a physical model that is much better suited for unusual targets.

  13. High energy cosmic rays

    CERN Document Server

    Stanev, Todor

    2010-01-01

    Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models

  14. Maria Montessori's Cosmic Vision, Cosmic Plan, and Cosmic Education

    Science.gov (United States)

    Grazzini, Camillo

    2013-01-01

    This classic position of the breadth of Cosmic Education begins with a way of seeing the human's interaction with the world, continues on to the grandeur in scale of time and space of that vision, then brings the interdependency of life where each growing human becomes a participating adult. Mr. Grazzini confronts the laws of human nature in…

  15. Ferrous Silicate Spherules with Euhedral Fe,Ni-Metal Grains in CH Carbonaceous Chondrites: Evidence for Condensation Under Highly Oxidizing Conditions

    Science.gov (United States)

    Krot, A. N.; Meibom, A.; Petaev, M. I.; Keil, K.; Zolensky, M. E.; Saito, A.; Mukai, M.; Ohsumi, K.

    2000-01-01

    A population of ferrous silicate spherules composed of cryptocrystalline ol-px-normative material, +/-SiO2-rich glass and rounded-to-euhedral Fe,Ni-metal grains preserved a condensation signature of the precursors formed under oxidizing conditions.

  16. Interactions of cosmic superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Mark G.; /Fermilab

    2007-06-01

    We develop methods by which cosmic superstring interactions can be studied in detail. These include the reconnection probability and emission of radiation such as gravitons or small string loops. Loop corrections to these are discussed, as well as relationships to (p; q)-strings. These tools should allow a phenomenological study of string models in anticipation of upcoming experiments sensitive to cosmic string radiation.

  17. Cosmic rays on earth

    Energy Technology Data Exchange (ETDEWEB)

    Allkofer, O.C.; Grieder, P.K.F.

    1984-01-01

    A data collection is presented that covers cosmic rays on earth. Included are all relevant data on flux and intensity measurements, energy spectra, and related data of all primary and secondary components of the cosmic radiation at all levels in the atmosphere, at sea level and underground. In those cases where no useful experimental data have been available, theoretical predictions were substituted.

  18. Clusters of Galaxies Shock Waves and Cosmic Rays

    CERN Document Server

    Ryu, D; Ryu, Dongsu; Kang, Hyesung

    2002-01-01

    Recent observations of galaxy clusters in radio and X-ray indicate that cosmic rays and magnetic fields may be energetically important in the intracluster medium. According to the estimates based on theses observational studies, the combined pressure of these two components of the intracluster medium may range between $10% \\sim 100 %$ of gas pressure, although their total energy is probably time dependent. Hence, these non-thermal components may have influenced the formation and evolution of cosmic structures, and may provide unique and vital diagnostic information through various radiations emitted via their interactions with surrounding matter and cosmic background photons. We suggest that shock waves associated with cosmic structures, along with individual sources such as active galactic nuclei and radio galaxies, supply the cosmic rays and magnetic fields to the intracluster medium and to surrounding large scale structures. In order to study 1) the properties of cosmic shock waves emerging during the larg...

  19. Platinum-group elements in the cores of potassium feldspar spherules from the Cretaceous-Tertiary boundary at Caravaca (Spain

    Directory of Open Access Journals (Sweden)

    Palomo, I.

    1994-04-01

    Full Text Available The abundant spherules present in the Cretaceous-Tertiary boundary layer at Caravaca are diagenetically transformed to potassium feldspar. Before our study no possible relicts of the precursor material had been reported. but in this paper we describe the presence of cores in these spherules that could represent a relict of the «unknown precursor». These cores are made up of C mixed with Si. Mg. AL Cr. Ca among other elements. Laser Ablation System analysis also reveals an enrichment in pe;E could suggest an extraterrestrial origin for this material. PI. Pd and Ir do not show a chondritic ratio: however. asevere modification of their concentration could be expected during the early diagenetic processes.Las esférulas existentes en la lámina de sedimento del tránsito Cretácico-Terciario de la sección de Caravaca han sido transformadas diagenéticamente a feldespato potásico. En este trabajo se describe la existencia de núcleos encontrados en el interior de las esférulas. los cuales' pueden representar relictos del material precursor. Dichos núcleos están constituidos por C. Si. Mg, AL Cr y Ca entre otros elementos. Se pone de relieve, por vez primera, su notable enriquecimiento en elementos del grupo del platino, cuyas relaciones no condríticas pueden ser debidas a la existencia de importantes modificaciones en su concentración inicial causadas por los procesos diagenéticos y por la existencia de materia orgánica.

  20. Eleventh European Cosmic Ray Symposium

    Science.gov (United States)

    1988-08-01

    The biannual Symposium includes all aspects of cosmic ray research. The scientific program was organized under three main headings: cosmic rays in the heliosphere, cosmic rays in the interstellar and extragalactic space, and properties of high-energy interactions as studied by cosmic rays. Selected short communications out of 114 contributed papers were indexed separately for the INIS database.

  1. Light scattering by cosmic particles

    NARCIS (Netherlands)

    Hovenier, J.W.; Min, M.

    2008-01-01

    We define cosmic particles as particles outside the Earth. Two types of cosmic particles can be distinguished, namely liquid and solid particles. The solid particles are often called grains or cosmic dust particles. Cosmic particles occur in a great variety of astronomical objects and environments.

  2. Supermassive cosmic string compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Pillado, Jose J.; Reina, Borja; Sousa, Kepa; Urrestilla, Jon, E-mail: josejuan.blanco@ehu.es, E-mail: borja.reina@ehu.es, E-mail: kepa.sousa@ehu.es, E-mail: jon.urrestilla@ehu.es [Department of Theoretical Physics and History of Science, University of the Basque Country UPV/EHU, 48080 Bilbao (Spain)

    2014-06-01

    The space-time dimensions transverse to a static straight cosmic string with a sufficiently large tension (supermassive cosmic strings) are compact and typically have a singularity at a finite distance form the core. In this paper, we discuss how the presence of multiple supermassive cosmic strings in the 4d Abelian-Higgs model can induce the spontaneous compactification of the transverse space and explicitly construct solutions where the gravitational background becomes regular everywhere. We discuss the embedding of this model in N = 1 supergravity and show that some of these solutions are half-BPS, in the sense that they leave unbroken half of the supersymmetries of the model.

  3. Supermassive Cosmic String Compactifications

    CERN Document Server

    Blanco-Pillado, Jose J; Sousa, Kepa; Urrestilla, Jon

    2014-01-01

    The space-time dimensions transverse to a static straight cosmic string with a sufficiently large tension (supermassive cosmic strings) are compact and typically have a singularity at a finite distance form the core. In this paper, we discuss how the presence of multiple supermassive cosmic strings in the 4D Abelian-Higgs model can induce the spontaneous compactification of the transverse space and explicitly construct solutions where the gravitational background becomes regular everywhere. We discuss the embedding of this model in N=1 supergravity and show that some of these solutions are half-BPS, in the sense that they leave unbroken half of the supersymmetries of the model.

  4. Cosmic Strings and Superstrings

    CERN Document Server

    Copeland, Edmund J

    2009-01-01

    Cosmic strings are predicted by many field-theory models, and may have been formed at a symmetry-breaking transition early in the history of the universe, such as that associated with grand unification. They could have important cosmological effects. Scenarios suggested by fundamental string theory or M-theory, in particular the popular idea of brane inflation, also strongly suggest the appearance of similar structures. Here we review the reasons for postulating the existence of cosmic strings or superstrings, the various possible ways in which they might be detected observationally, and the special features that might discriminate between ordinary cosmic strings and superstrings.

  5. Habitability and cosmic catastrophes

    CERN Document Server

    Hanslmeier, Arnold; McKay, Christopher P

    2008-01-01

    Catastrophic cosmic events such as asteroid impacts appear in the range of some 100 million years and have drastically affected evolution. The author discusses whether and how such events could have occurred in recently found extrasolar planetary systems.

  6. Astrophysics: Cosmic jet engines

    Science.gov (United States)

    Young, Andy

    2010-02-01

    In some galaxies, matter falling onto a supermassive black hole is ejected in narrow jets moving at close to the speed of light. New observations provide insight into the workings of these cosmic accelerators.

  7. Highest Energy Cosmic Rays

    CERN Document Server

    Frampton, Paul H

    1998-01-01

    It is proposed that the highest energy $\\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor whose high kinetic energy arises from decay of a distant (cosmological) superheavy particle, G. Such a scenario can occur in e.g. SU(15) grand unification and in some preon models, but is more generic; if true, these unusual cosmic rays provide a window into new physics.

  8. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  9. New constraints on the Paleoarchean meteorite bombardment of the Earth - Geochemistry and Re-Os isotope signatures of spherule layers in the BARB5 ICDP drill core from the Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Schulz, Toni; Koeberl, Christian; Luguet, Ambre; van Acken, David; Mohr-Westheide, Tanja; Ozdemir, Seda; Reimold, Wolf Uwe

    2017-08-01

    Archean spherule layers, resulting from impacts by large extraterrestrial objects, to date represent the only remnants of the early meteorite, asteroid, and comet bombardment of the Earth. Only few Archean impact debris layers have been documented, all of them embedded in the 3.23-3.47 billion year old successions of the Barberton Greenstone Belt (BGB) in South Africa and the Pilbara Craton in Western Australia. Some of them might be correlated with each other. Given the scarcity of Archean spherule deposits, four spherule layer intersections from the recently recovered BARB5 drill core from the central Barberton Greenstone Belt, analyzed in this study, provide an opportunity to gain new insight into the early terrestrial impact bombardment. Despite being hydrothermally overprinted, siderophile element abundance signatures of spherule-rich samples from the BARB5 drill core, at least in part, retained a meteoritic fingerprint. The impact hypothesis for the generation of the BARB5 spherule layers is supported by correlations between the abundances of moderately (Cr, Co, Ni) and highly siderophile (Re, Os, Ir, Pt, Ru and Pd) elements, whose peak concentrations and interelement ratios are within the range of those for chondrites. Rhenium-Osmium isotope evidence further support the impact hypothesis. Collectively, this study provides evidence for extraterrestrial admixtures ranging between ∼40 and up to 100% to three of the four analyzed BARB5 spherule layers, and a scenario for their genesis involving (i) impact of a chondritic bolide into a sedimentary target, (ii) varying admixtures of meteoritic components to target materials, (iii) spherule formation via condensation in an impact vapor plume, (iv) transportation of the spherules and sedimentation under submarine conditions, followed by (v) moderate post-impact remobilization of transition metals and highly siderophile elements.

  10. Lagrangian Methods Of Cosmic Web Classification

    CERN Document Server

    Fisher, J D; Johnson, M S T

    2015-01-01

    The cosmic web defines the large scale distribution of matter we see in the Universe today. Classifying the cosmic web into voids, sheets, filaments and nodes allows one to explore structure formation and the role environmental factors have on halo and galaxy properties. While existing studies of cosmic web classification concentrate on grid based methods, this work explores a Lagrangian approach where the V-web algorithm proposed by Hoffman et al. (2012) is implemented with techniques borrowed from smoothed particle hydrodynamics. The Lagrangian approach allows one to classify individual objects (e.g. particles or halos) based on properties of their nearest neighbours in an adaptive manner. It can be applied directly to a halo sample which dramatically reduces computational cost and potentially allows an application of this classification scheme to observed galaxy samples. Finally, the Lagrangian nature admits a straight forward inclusion of the Hubble flow negating the necessity of a visually defined thresh...

  11. FE-SEM, FIB and TEM Study of Surface Deposits of Apollo 15 Green Glass Volcanic Spherules

    Science.gov (United States)

    Ross, Daniel K.; Thomas-Keprta, K. L.; Rahman, Z.; Wentworth, S. J.; McKay, D. S.

    2011-01-01

    Surface deposits on lunar pyroclastic green (Apollo 15) and orange (Apollo 17) glass spherules have been attributed to condensation from the gas clouds that accompanied fire-fountain eruptions. The fire fountains cast molten lava high above the lunar surface and the silicate melt droplets quenched before landing producing the glass beads. Early investigations showed that these deposits are rich in sulfur and zinc. The deposits are extremely fine-grained and thin, so that it was never possible to determine their chemical compositions cleanly by SEM/EDX or electron probe x-ray analysis because most of the excited volume was in the under-lying silicate glass. We are investigating the surface deposits by TEM, using focused ion beam (FIB) microscopy to extract and thin the surface deposits. Here we report on chemical mapping of a FIB section of surface deposits of an Apollo green glass bead 15401using the ultra-high resolution JEOL 2500 STEM located at NASA Johnson Space Center.

  12. Cosmic Rays and Climate

    CERN Document Server

    Kirkby, Jasper

    2007-01-01

    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 controversial—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...

  13. Constraints On Cosmic Dynamics

    CERN Document Server

    Mbonye, M R

    2003-01-01

    Observationally, the universe appears virtually critical. Yet, there is no simple explanation for this state. In this article we advance and explore the premise that the dynamics of the universe always seeks equilibrium conditions. Vacuum-induced cosmic accelerations lead to creation of matter-energy modes at the expense of vacuum energy. Because they gravitate, such modes constitute inertia against cosmic acceleration. On the other extreme, the would-be ultimate phase of local gravitational collapse is checked by a phase transition in the collapsing matter fields leading to a de Sitter-like fluid deep inside the black hole horizon, and at the expense of the collapsing matter fields. As a result, the universe succumbs to neither vacuum-induced run-away accelerations nor to gravitationally induced spacetime curvature singularities. Cosmic dynamics is self-regulating. We discuss the physical basis for these constraints and the implications, pointing out how the framework relates and helps resolve standing puzzl...

  14. Mapping the Cosmic Dawn

    Science.gov (United States)

    Furlanetto, Steven

    The following sections are included: * A Brief History of Our Universe: From Soup to Galaxies * The Hidden Cosmic Dawn * The Solution: Flipping Spins * The Spin-Flip Transition as an Astronomical Tool * Foiled!: Early Cosmology with the Spin-Flip Transition * Spin-Flip Radiation Holds the Key to Observing the Cosmic Dawn * The Spin-Flip Background: The First Stars * The Spin-Flip Background: The First Black Holes * The Spin-Flip Background: The Epoch of Reionization * FM Radio Antennae as Cosmic Observatories * Piles and Tiles of Antennae: Mapping the Spin-Flip Background * Mountains to Scale: Challenges to Observing the Spin-Flip Background * Sound and Fury, Signifying Statistics * An Explosion of Telescopes * Dreams for the Future * An Unfinished Story

  15. A cosmic book

    Science.gov (United States)

    Peebles, P. J. E.; Silk, Joseph

    1988-10-01

    A system of assigning odds to the basic elements of cosmological theories is proposed in order to evaluate the strengths and weaknesses of the theories. A figure of merit for the theories is obtained by counting and weighing the plausibility of each of the basic elements that is not substantially supported by observation or mature fundamental theory. The magnetized strong model is found to be the most probable. In order of decreasing probability, the ranking for the rest of the models is: (1) the magnetized string model with no exotic matter and the baryon adiabatic model; (2) the hot dark matter model and the model of cosmic string loops; (3) the canonical cold dark matter model, the cosmic string loops model with hot dark matter, and the baryonic isocurvature model; and (4) the cosmic string loops model with no exotic matter.

  16. Cosmic Dawn Intensity Mapper

    CERN Document Server

    Cooray, Asantha; Burgarella, Denis; Chary, Ranga; Chang, Tzu-Ching; Doré, Olivier; Fazio, Giovanni; Ferrara, Andrea; Gong, Yan; Santos, Mario; Silva, Marta; Zemcov, Michael

    2016-01-01

    Cosmic Dawn Intensity Mapper is a "Probe Class" mission concept for reionization studies of the universe. It will be capable of spectroscopic imaging observations between 0.7 to 6-7 microns in the near-Infrared. The primary observational objective is pioneering observations of spectral emission lines of interest throughout the cosmic history, but especially from the first generation of distant, faint galaxies when the universe was less than 800 million years old. With spectro-imaging capabilities, using a set of linear variable filters (LVFs), CDIM will produce a three-dimensional tomographic view of the epoch of reionization (EoR). CDIM will also study galaxy formation over more than 90% of the cosmic history and will move the astronomical community from broad-band astronomical imaging to low-resolution (R=200-300) spectro-imaging of the universe.

  17. A disintegrating cosmic string

    CERN Document Server

    Griffiths, J B

    2002-01-01

    We present a simple sandwich gravitational wave of the Robinson-Trautman family. This is interpreted as representing a shock wave with a spherical wavefront which propagates into a Minkowski background minus a wedge. (i.e. the background contains a cosmic string.) The deficit angle (the tension) of the string decreases through the gravitational wave, which then ceases. This leaves an expanding spherical region of Minkowski space behind it. The decay of the cosmic string over a finite interval of retarded time may be considered to generate the gravitational wave.

  18. Cosmic Sum Rules

    DEFF Research Database (Denmark)

    T. Frandsen, Mads; Masina, Isabella; Sannino, Francesco

    2011-01-01

    We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models.......We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models....

  19. Dynamic Cosmic Strings, 1

    CERN Document Server

    Sjodin, K R P; Vickers, J A

    2001-01-01

    The field equations for a time dependent cylindrical cosmic string coupled togravity are reformulated in terms of geometrical variables defined on a2+1-dimensional spacetime by using the method of Geroch decomposition. Unlikethe 4-dimensional spacetime the reduced case is asymptotically flat. Anumerical method for solving the field equations which involves conformallycompactifying the space and including null infinity as part of the grid isdescribed. It is shown that the code reproduces the results of a number ofvacuum solutions with one or two degrees of freedom. In the final section theinteraction between the cosmic string and a pulse of gravitational radiation isbriefly described. This will be fully analysed in the sequel.

  20. The Cosmic Microwave Background

    OpenAIRE

    Silk, Joseph

    2002-01-01

    This set of lectures provides an overview of the basic theory and phenomenology of the cosmic microwave background. Topics include a brief historical review; the physics of temperature and polarization fluctuations; acoustic oscillations of the primordial plasma; the space of inflationary cosmological models; current and potential constraints on these models from the microwave background; and constraints on inflation.

  1. Simulating Cosmic Reionisation

    NARCIS (Netherlands)

    Pawlik, Andreas Heinz

    2009-01-01

    The first stars formed a few hundred million years after the Big Bang, when the Universe was only a small fraction of its present age. Their radiation transformed the previously cold and neutral hydrogen that filled intergalactic space into the hot and ionised cosmic plasma that is observed today. T

  2. Simulating Cosmic Reionisation

    NARCIS (Netherlands)

    Pawlik, Andreas Heinz

    2009-01-01

    The first stars formed a few hundred million years after the Big Bang, when the Universe was only a small fraction of its present age. Their radiation transformed the previously cold and neutral hydrogen that filled intergalactic space into the hot and ionised cosmic plasma that is observed today.

  3. Antarctic Cosmic Ray Astronomy

    Science.gov (United States)

    Duldig, Marc

    Cosmic ray observations related to Antarctica commenced in the austral summer of 1947-48 from sub-Antarctic Heard and Macquarie Islands and from the HMAS Wyatt Earp. Muon telescope observations from Mawson station Antarctica commenced in 1955. The International Geophysical Year was the impetus for the installation of a number of neutron monitors around Antarctica observing the lowest energy cosmic rays accessible by ground based instruments. In 1971 a new observatory was built at Mawson including the only underground muon telescope system at polar latitudes in either hemisphere. In the 1980s the South Pole Air Shower Experiment (SPASE) opened the highest energy cosmic ray window over Antarctica and this was followed by the in-ice neutrino experiment AMANDA. Over more than half a century cosmic ray astronomy has been undertaken from Antarctica and its surrounding regions and these observations have been critical to our growing understanding of nearby astrophysical structures. For example the Parker spiral magnetic field of the sun was confirmed through Mawson observations of a Solar flare induced Ground Level Enahncement in 1960 long before spacecraft were able to directly observe the interplanetary magnetic field. A summary of the Antarctic instrumental developments and the scientific advances that resulted will be presented.

  4. Hydrology and Cosmic radiation

    DEFF Research Database (Denmark)

    Andreasen, Mie

    and calibration. Yet, soil moisture measurements are traditionally provided on either point or kilometer scale from electromagnetic based sensors and satellite retrievals, respectively. Above the ground surface, the cosmic-ray neutron intensity (eV range) is inversely correlated to all hydrogen present...

  5. Cosmic rays and climate

    CERN Multimedia

    2009-01-01

    Inside the new chamber the CLOUD team will be able to recreate the conditions of any part of the atmosphere, from the polar stratosphere to the low level tropics (top). The new chamber safely in position in the East hall. Once carefully cleaned the chamber will be turned sideways onto its legs ready for the beam of 'cosmic rays' (bottom).

  6. Cosmic Dust and the Earth's Atmosphere (Vilhelm Bjerknes Medal Lecture)

    Science.gov (United States)

    Plane, John M. C.

    2017-04-01

    chemical ablation model to determine the rate of injection of metallic vapours into the atmosphere. Constraining these coupled models with lidar measurements of the vertical fluxes of Na and Fe in the MLT, and the rate of accretion of cosmic spherules at the South Pole, indicates that about 40 tonnes of dust enters the atmosphere each day, of which ˜18% ablates. The subsequent atmospheric chemistry of the ablated metallic vapours is then examined using the Whole Atmosphere Community Climate Model (WACCM), coupled with the aerosol microphysics model CARMA to treat the interplay of meteoric smoke particles with the stratospheric sulphate layer. While the optical extinction of meteoric smoke in the lower mesosphere, and of refractory material in polar stratospheric clouds is satisfactorily modelled, two problems remain. First, the injection rate of Na and Fe atoms is too large (by a factor between 5 and 10) for WACCM to replicate the observed metal atom layer densities in the MLT. It appears that vertical transport by eddy diffusion has to be significantly supplemented by chemical transport produced by unresolved (sub-grid) gravity waves (this process will significantly affect the transport of other species such as atomic O through the MLT). The second problem is that the rate of deposition of MSPs at polar latitudes is substantially underestimated by the model, indicating that there may be an efficient process for removing particles directly from the lower stratospheric winter polar vortex to the surface. Underpinning the model development are three novel experimental systems developed at Leeds: a Meteor Ablation Simulator, which measures the evaporation of metals from cosmic dust particles that are flash heated to over 2800 K; a Time-of-Flight mass spectrometer with laser photo-ionization which is used to study the reactions of neutral metallic compounds in the gas phase; and a flowing afterglow experiment to study the dissociative recombination of metallic ions with

  7. Cosmic Rays at Earth

    Science.gov (United States)

    Grieder, P. K. F.

    In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery. Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary particle physics, modern astrophysics and cosmology are direct consequences of this discovery. Over the years the field of cosmic ray research has evolved in various directions: Firstly, the field of particle physics that was initiated by the discovery of many so-called elementary particles in the cosmic radiation. There is a strong trend from the accelerator physics community to reenter the field of cosmic ray physics, now under the name of astroparticle physics. Secondly, an important branch of cosmic ray physics that has rapidly evolved in conjunction with space exploration concerns the low energy portion of the cosmic ray spectrum. Thirdly, the branch of research that is concerned with the origin, acceleration and propagation of the cosmic radiation represents a great challenge for astrophysics, astronomy and cosmology. Presently very popular fields of research have rapidly evolved, such as high-energy gamma ray and neutrino astronomy. In addition, high-energy neutrino astronomy may soon initiate as a likely spin-off neutrino tomography of the Earth and thus open a unique new branch of geophysical research of the interior of the Earth. Finally, of considerable interest are the biological

  8. Density, porosity, mineralogy, and internal structure of cosmic dust and alteration of its properties during high velocity atmospheric entry

    CERN Document Server

    Kohout, T; Suuronen, J -P; Rochette, P; Hutzler, A; Gattacceca, J; Skála, D D Badjukov R; Böhmová, V; Čuda, J

    2014-01-01

    X-ray microtomography (XMT), X-ray diffraction (XRD) and magnetic hysteresis measurements were used to determine micrometeorite internal structure, mineralogy, crystallography, and physical properties at ~{\\mu}m resolution. The study samples include unmelted, partially melted (scoriaceous) and completely melted (cosmic spherules) micrometeorites. This variety not only allows comparison of the mineralogy and porosity of these three micrometeorite types, but also reveals changes in meteoroid properties during atmospheric entry at various velocities. At low entry velocities, meteoroids do not melt, and their physical properties do not change. The porosity of unmelted micrometeorites varies considerably (0-12%) with one friable example having porosity around 50%. At higher velocities, the range of meteoroid porosity narrows, but average porosity increases (to 16-27%) due to volatile evaporation and partial melting (scoriaceous phase). Metal distribution seems to be mostly unaffected at this stage. At even higher ...

  9. Cosmic radiation exposure and persistent cognitive dysfunction

    Science.gov (United States)

    Parihar, Vipan K.; Allen, Barrett D.; Caressi, Chongshan; Kwok, Stephanie; Chu, Esther; Tran, Katherine K.; Chmielewski, Nicole N.; Giedzinski, Erich; Acharya, Munjal M.; Britten, Richard A.; Baulch, Janet E.; Limoli, Charles L.

    2016-01-01

    The Mars mission will result in an inevitable exposure to cosmic radiation that has been shown to cause cognitive impairments in rodent models, and possibly in astronauts engaged in deep space travel. Of particular concern is the potential for cosmic radiation exposure to compromise critical decision making during normal operations or under emergency conditions in deep space. Rodents exposed to cosmic radiation exhibit persistent hippocampal and cortical based performance decrements using six independent behavioral tasks administered between separate cohorts 12 and 24 weeks after irradiation. Radiation-induced impairments in spatial, episodic and recognition memory were temporally coincident with deficits in executive function and reduced rates of fear extinction and elevated anxiety. Irradiation caused significant reductions in dendritic complexity, spine density and altered spine morphology along medial prefrontal cortical neurons known to mediate neurotransmission interrogated by our behavioral tasks. Cosmic radiation also disrupted synaptic integrity and increased neuroinflammation that persisted more than 6 months after exposure. Behavioral deficits for individual animals correlated significantly with reduced spine density and increased synaptic puncta, providing quantitative measures of risk for developing cognitive impairment. Our data provide additional evidence that deep space travel poses a real and unique threat to the integrity of neural circuits in the brain. PMID:27721383

  10. Cosmic radiation exposure and persistent cognitive dysfunction.

    Science.gov (United States)

    Parihar, Vipan K; Allen, Barrett D; Caressi, Chongshan; Kwok, Stephanie; Chu, Esther; Tran, Katherine K; Chmielewski, Nicole N; Giedzinski, Erich; Acharya, Munjal M; Britten, Richard A; Baulch, Janet E; Limoli, Charles L

    2016-10-10

    The Mars mission will result in an inevitable exposure to cosmic radiation that has been shown to cause cognitive impairments in rodent models, and possibly in astronauts engaged in deep space travel. Of particular concern is the potential for cosmic radiation exposure to compromise critical decision making during normal operations or under emergency conditions in deep space. Rodents exposed to cosmic radiation exhibit persistent hippocampal and cortical based performance decrements using six independent behavioral tasks administered between separate cohorts 12 and 24 weeks after irradiation. Radiation-induced impairments in spatial, episodic and recognition memory were temporally coincident with deficits in executive function and reduced rates of fear extinction and elevated anxiety. Irradiation caused significant reductions in dendritic complexity, spine density and altered spine morphology along medial prefrontal cortical neurons known to mediate neurotransmission interrogated by our behavioral tasks. Cosmic radiation also disrupted synaptic integrity and increased neuroinflammation that persisted more than 6 months after exposure. Behavioral deficits for individual animals correlated significantly with reduced spine density and increased synaptic puncta, providing quantitative measures of risk for developing cognitive impairment. Our data provide additional evidence that deep space travel poses a real and unique threat to the integrity of neural circuits in the brain.

  11. {mu}-Synchrotron radiation excited X-ray fluorescence microprobe trace element studies on spherules of the Cretaceous/Tertiary boundary transitions of NE-Mexico and Haiti samples

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, Utz [Universitaet Karlsruhe (Thailand), Institut fuer Mineralogie und Geochemie, Kaiserstrasse 12, D-76128 Karlsruhe (Germany)], E-mail: utz.kramar@img.uni-karlsruhe.de; Harting, Markus [Utrecht University, Department of Earthsciences, Budapestlaan 4, 3508 TA Utrecht (Netherlands); Rickers, Karen [Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); GeoForschungsZentrum Potsdam, Division 4.1, Telegrafenberg, 14473 Potsdam (Germany); Stueben, Doris [Universitaet Karlsruhe (Thailand), Institut fuer Mineralogie und Geochemie, Kaiserstrasse 12, D-76128 Karlsruhe (Germany)

    2007-08-15

    Synchrotron radiation, collimated to a {mu}m scale was used for the determination of trace elements in micro-tektites and spherule material for the first time. The experimental set-up of the SXRF microprobe at beamline L at HASYLAB at DESY offers a suitable method for performing non-destructive in situ multi-element analysis focusing on spatial trace element distributions and mineral phases of the melted ejecta material from the Cretaceous/Tertiary boundary. The spatial distribution of trace elements was determined in melt inclusions as well as in phase transitions in selected parts of chlorite-smectite spherules and tektite glass material by using a beam with a diameter of 15 {mu}m collimated with a glass capillary for line- and area scans as well as for single point measurements for elements with Z between 19 and 92. The analyzed spherules show alteration features but also zonation and carbonate inclusions, originating from the Chicxulub impact event. These initial results demonstrate the potential of {mu}-SXRF analysis for the discrimination of alteration and primary signals of the spherules and re-construction of their genetic evolution. It could be shown that the spherules represent a complex mixture of different materials from the subsurface at the Chicxulub impact site.

  12. Dual Phase Cosmic Rays

    CERN Document Server

    Shurtleff, Richard

    2008-01-01

    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.

  13. Cosmic structure formation

    Science.gov (United States)

    Bertschinger, Edumund

    1994-01-01

    This article reviews the prevailing paradigm for how galaxies and larger structures formed in the universe: gravitational instability. Basic observational facts are summarized to motivate the standard cosmological framework underlying most detailed investigations of structure formation. The observed univers approaches spatial uniformity on scales larger than about 10(exp 26) cm. On these scales gravitational dynamics is almost linear and therefore relatively easy to relate to observations of large-scale structure. On smaller scales cosmic structure is complicated not only by nonlinear gravitational clustering but also by nonlinear nongravitational gas dynamical processes. The complexity of these phenomena makes galaxy formation one of the grand challenge problems of the physical sciences. No fully satisfactory theory can presently account in detail for the observed cosmic structure. However, as this article summarizes, significant progress has been made during the last few years.

  14. Understanding the cosmic web

    CERN Document Server

    Cautun, Marius; Jones, Bernard J T; Frenk, Carlos S

    2015-01-01

    We investigate the characteristics and the time evolution of the cosmic web from redshift, z=2, to present time, within the framework of the NEXUS+ algorithm. This necessitates the introduction of new analysis tools optimally suited to describe the very intricate and hierarchical pattern that is the cosmic web. In particular, we characterize filaments (walls) in terms of their linear (surface) mass density. This is very good in capturing the evolution of these structures. At early times the cosmos is dominated by tenuous filaments and sheets, which, during subsequent evolution, merge together, such that the present day web is dominated by fewer, but much more massive, structures. We also show that voids are more naturally described in terms of their boundaries and not their centres. We illustrate this for void density profiles, which, when expressed as a function of the distance from void boundary, show a universal profile in good qualitative agreement with the theoretical shell-crossing framework of expandin...

  15. Cosmic rays and climate

    CERN Document Server

    CERN. Geneva

    2009-01-01

    The current understanding of climate change in the industrial age is that it is predominantly caused by anthropogenic greenhouse gases, with relatively small natural contributions due to solar irradiance and volcanoes. However, palaeoclimatic reconstructions show that the climate has frequently varied on 100-year time scales during the Holocene (last 10 kyr) by amounts comparable to the present warming - and yet the mechanism or mechanisms are not understood. Some of these reconstructions show clear associations with solar variability, which is recorded in the light radio-isotope archives that measure past variations of cosmic ray intensity. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Estimated changes of solar irradiance on these time scales appear to be too small to account for the climate observations. This raises the question of whether cosmic rays may directly affect the climate, provi...

  16. Note on cosmic censorship

    Science.gov (United States)

    Tipler, F. J.

    1985-05-01

    A number of recent theorems by Krolak (1983) and Newman (1983) purport to prove cosmic censorship by showing that strong-curvature singularities must be hidden behind horizons. It is shown that the 'null strong-curvature' condition which Newman imposes on certain classes of null geodesics to restrict curvature growth in the space-time does not hold in many physically realistic space-times: it is not satisfied by any null geodesic in the relevant class in any open Friedmann cosmological model, nor does it hold for any null geodesic in the relevant class in maximal Schwarzschild space. More generally it is argued that the singularity predicted by the Penrose singularity theorem is unlikely to be of the type eliminated by Newman. Thus the Newman theorems are probably without physical significance. The Krolak theorems, although based on a physically significant definition of strong curvature singularity, are mathematically invalid, and this approach cannot be used to obtain a cosmic-censorship theorem.

  17. Cosmic Tidal Reconstruction

    CERN Document Server

    Zhu, Hong-Ming; Yu, Yu; Er, Xinzhong; Chen, Xuelei

    2015-01-01

    The gravitational coupling of a long wavelength tidal field with small scale density fluctuations leads to anisotropic distortions of the locally measured small scale matter correlation function. Since the local correlation function is statistically isotropic in the absence of such tidal interactions, the tidal distortions can be used to reconstruct the long wavelength tidal field and large scale density field in analogy with the cosmic microwave background lensing reconstruction. In this paper we present in detail a formalism for the cosmic tidal reconstruction and test the reconstruction in numerical simulations. We find that the density field on large scales can be reconstructed with good accuracy and the cross correlation coefficient between the reconstructed density field and the original density field is greater than 0.9 on large scales ($k\\lesssim0.1h/\\mathrm{Mpc}$). This is useful in the 21cm intensity mapping survey, where the long wavelength radial modes are lost due to foreground subtraction proces...

  18. Stable charged cosmic strings.

    Science.gov (United States)

    Weigel, H; Quandt, M; Graham, N

    2011-03-11

    We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius ≈10(-18)  m. The vacuum remains stable in our model, because neutral strings are not energetically favored.

  19. Cosmic Plasma Wakefield Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P

    2004-04-26

    Recently we proposed a new cosmic acceleration mechanism which was based on the wakefields excited by the Alfven shocks in a relativistically owing plasma. In this paper we include some omitted details, and show that there exists a threshold condition for transparency below which the accelerating particle is collision-free and suffers little energy loss in the plasma medium. The stochastic encounters of the random accelerating-decelerating phases results in a power-law energy spectrum: f({epsilon}) {proportional_to} 1/{epsilon}{sup 2}. As an example, we discuss the possible production of super-GZK ultra high energy cosmic rays (UHECR) in the atmosphere of gamma ray bursts. The estimated event rate in our model agrees with that from UHECR observations.

  20. Cosmic Strings and Quintessence

    Institute of Scientific and Technical Information of China (English)

    段一士; 任继荣; 杨捷

    2003-01-01

    Using torsion two-form we present a new Lorentz gauge invariant U (1) topological field theory in Riemann-Cartan space-time manifold U4. By virtue of the decomposition theory of U(1) gauge potential and the φ-mapping topological current theory, it is proven that the U(1) complex scalar field φ(x) can be looked upon as the order parameter field in our Universe, and a set of zero points of φ(x) create the cosmic strings as the space-time defects in the early Universe. In the standard cosmology, this complex scalar order parameter field possesses negative pressure, provides an accelerating expansion of Universe, and be able to explain the inflation in the early Universe. Therefore this complex scalar field is not only the order parameter field created the cosmic strings in the early universe, but also reasonably behaves as the quintessence, the dark energy.

  1. Modeling cosmic void statistics

    Science.gov (United States)

    Hamaus, Nico; Sutter, P. M.; Wandelt, Benjamin D.

    2016-10-01

    Understanding the internal structure and spatial distribution of cosmic voids is crucial when considering them as probes of cosmology. We present recent advances in modeling void density- and velocity-profiles in real space, as well as void two-point statistics in redshift space, by examining voids identified via the watershed transform in state-of-the-art ΛCDM n-body simulations and mock galaxy catalogs. The simple and universal characteristics that emerge from these statistics indicate the self-similarity of large-scale structure and suggest cosmic voids to be among the most pristine objects to consider for future studies on the nature of dark energy, dark matter and modified gravity.

  2. Carl Sagan's Cosmic Connection

    Science.gov (United States)

    Sagan, Carl; Agel, Jerome

    2000-08-01

    Foreword Freeman Dyson; Personal reflections Ann Druyan; Preface; Part I. Cosmic Perspective: 1. A transitional animal; 2. The Unicorn of Cetus; 3. A message from earth; 4. A message to earth; 5. Experiments in utopias; 6. Chauvinism; 7. Space exploration as a human enterprise I. The scientific interest; 8. Space exploration as a human enterprise II. The public interest; 9. Space exploration as a human enterprise III. The historical interest; Part II. The Solar System: 10. On teaching the first grade; 11. 'The ancient and legendary Gods of old'; 12. The Venus detective story; 13. Venus is hell; 14. Science and 'intelligence'; 15. The moons of Barsoom; 16. The mountains of Mars I. Observations from earth; 17. The mountains of Mars II. Observations from space; 18. The canals of Mars; 19. The lost pictures of Mars; 20. The Ice Age and the cauldron; 21. Beginnings and ends of the Earth; 22. Terraforming the plants; 23. The exploration and utlization of the solar system; Part III. Beyond the Solar System: 24. Some of my best friends are dolphins; 25. 'Hello, central casting? Send me twenty extraterrestrials'; 26. The cosmic connection; 27. Extraterrestrial life: an idea whose time has come; 28. Has the Earth been visited?; 29. A search strategy for detecting extraterrestrial intelligence; 30. If we succeed 31. Cables, drums, and seashells; 32. The night freight to the stars; 33. Astroengineering; 34. Twenty questions: a classification of cosmic civilisations; 35. Galactic cultural exchanges; 36. A passage to elsewhere; 37. Starfolk I. A Fable; 38. Starfolk II. A future; 39. Starfolk III. The cosmic Cheshire cats; Epilog David Morrison; Index.

  3. Cosmic Rays in Thunderstorms

    Science.gov (United States)

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

    2013-04-01

    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)

  4. Cosmic microwave background theory.

    Science.gov (United States)

    Bond, J R

    1998-01-06

    A long-standing goal of theorists has been to constrain cosmological parameters that define the structure formation theory from cosmic microwave background (CMB) anisotropy experiments and large-scale structure (LSS) observations. The status and future promise of this enterprise is described. Current band-powers in -space are consistent with a DeltaT flat in frequency and broadly follow inflation-based expectations. That the levels are approximately (10(-5))2 provides strong support for the gravitational instability theory, while the Far Infrared Absolute Spectrophotometer (FIRAS) constraints on energy injection rule out cosmic explosions as a dominant source of LSS. Band-powers at 100 suggest that the universe could not have re-ionized too early. To get the LSS of Cosmic Background Explorer (COBE)-normalized fluctuations right provides encouraging support that the initial fluctuation spectrum was not far off the scale invariant form that inflation models prefer: e.g., for tilted Lambda cold dark matter sequences of fixed 13-Gyr age (with the Hubble constant H0 marginalized), ns = 1.17 +/- 0.3 for Differential Microwave Radiometer (DMR) only; 1.15 +/- 0.08 for DMR plus the SK95 experiment; 1.00 +/- 0.04 for DMR plus all smaller angle experiments; 1.00 +/- 0.05 when LSS constraints are included as well. The CMB alone currently gives weak constraints on Lambda and moderate constraints on Omegatot, but theoretical forecasts of future long duration balloon and satellite experiments are shown which predict percent-level accuracy among a large fraction of the 10+ parameters characterizing the cosmic structure formation theory, at least if it is an inflation variant.

  5. Frontiers in Cosmic Rays

    CERN Document Server

    Anchordoqui, Luis A; Ringwald, Andreas; Anchordoqui, Luis A.; Dermer, Charles D.; Ringwald, Andreas

    2004-01-01

    This rapporteur review covers selected results presented in the Parallel Session HEA2 (High Energy Astrophysics 2) of the 10th Marcel Grossmann Meeting on General Relativity, held in Rio de Janeiro, Brazil, July 2003. The subtopics are: ultra high energy cosmic ray anisotropies, the possible connection of these energetic particles with powerful gamma ray bursts, and new exciting scenarios with a strong neutrino-nucleon interaction in the atmosphere.

  6. Cosmic ray modulation

    Science.gov (United States)

    Agarwal Mishra, Rekha; Mishra, Rajesh Kumar

    2016-07-01

    Propagation of cosmic rays to and inside the heliosphere, encounter an outward moving solar wind with cyclic magnetic field fluctuation and turbulence, causing convection and diffusion in the heliosphere. Cosmic ray counts from the ground ground-based neutron monitors at different cut of rigidity show intensity changes, which are anti-correlated with sunspot numbers. They also lose energy as they propagate towards the Earth and experience various types of modulations due to different solar activity indices. In this work, we study the first three harmonics of cosmic ray intensity on geo-magnetically quiet days over the period 1965-2014 for Beijing, Moscow and Tokyo neutron monitoring stations located at different cut off rigidity. The amplitude of first harmonic remains high for low cutoff rigidity as compared to high cutoff rigidity on quiet days. The diurnal amplitude significantly decreases during solar activity minimum years. The diurnal time of maximum significantly shifts to an earlier time as compared to the corotational direction having different cutoff rigidities. The time of maximum for first harmonic significantly shifts towards later hours and for second harmonic it shifts towards earlier hours at low cutoff rigidity station as compared to the high cut off rigidity station on quiet days. The amplitude of second/third harmonics shows a good positive correlation with solar wind velocity, while the others (i.e. amplitude and phase) have no significant correlation on quiet days. The amplitude and direction of the anisotropy on quiet days does not show any significant dependence on high-speed solar wind streams for these neutron monitoring stations of different cutoff rigidity threshold. Keywords: cosmic ray, cut off rigidity, quiet days, harmonics, amplitude, phase.

  7. A Cosmic Microwave Background feature consistent with a cosmic texture

    OpenAIRE

    Cruz, M.; Turok, N.; Vielva, P.; Martinez-Gonzalez, E.; Hobson, M.

    2007-01-01

    The Cosmic Microwave Background provides our most ancient image of the Universe and our best tool for studying its early evolution. Theories of high energy physics predict the formation of various types of topological defects in the very early universe, including cosmic texture which would generate hot and cold spots in the Cosmic Microwave Background. We show through a Bayesian statistical analysis that the most prominent, 5 degree radius cold spot observed in all-sky images, which is otherw...

  8. Canny Algorithm, Cosmic Strings and the Cosmic Microwave Background

    Science.gov (United States)

    Danos, Rebecca J.; Brandenberger, Robert H.

    We describe a new code to search for signatures of cosmic strings in cosmic microwave anisotropy maps. The code implements the Canny algorithm, an edge detection algorithm designed to search for the lines of large gradients in maps. Such a gradient signature which is coherent in position-space is produced by cosmic strings via the Kaiser-Stebbins effect. We test the power of our new code to set limits on the tension of the cosmic strings by analyzing simulated data, with and without cosmic strings. We compare maps with a pure Gaussian scale-invariant power spectrum with maps which have a contribution of a distribution of cosmic strings obeying a scaling solution. The maps have angular scale and angular resolution comparable to what current and future ground-based small-scale cosmic microwave anisotropy experiments will achieve. We present tests of the codes, indicate the limits on the string tension which could be set with the current code, and describe various ways to refine the analysis. Our results indicate that when applied to the data of ongoing cosmic microwave experiments such as the South Pole Telescope project, the sensitivity of our method to the presence of cosmic strings will be more than an order of magnitude better than the limits from existing analyses.

  9. Cosmic ray driven Galactic winds

    Science.gov (United States)

    Recchia, S.; Blasi, P.; Morlino, G.

    2016-11-01

    The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas from the Galaxy, thereby regulating several physical processes, including star formation. The dynamics of these cosmic ray driven winds is intrinsically non-linear in that the spectrum of cosmic rays determines the characteristics of the wind (velocity, pressure, magnetic field) and in turn the wind dynamics affects the cosmic ray spectrum. Moreover, the gradient of the cosmic ray distribution function causes excitation of Alfvén waves, that in turn determines the scattering properties of cosmic rays, namely their diffusive transport. These effects all feed into each other so that what we see at the Earth is the result of these non-linear effects. Here, we investigate the launch and evolution of such winds, and we determine the implications for the spectrum of cosmic rays by solving together the hydrodynamical equations for the wind and the transport equation for cosmic rays under the action of self-generated diffusion and advection with the wind and the self-excited Alfvén waves.

  10. Cosmic ray: Studying the origin

    Energy Technology Data Exchange (ETDEWEB)

    Szabelski, J. [Cosmic Ray Laboratory, Soltan Institute for Nuclear Studies, Lodz (Poland)

    1997-12-31

    Investigations of the origin of cosmic rays are presented. Different methods are discussed: studies of cosmic gamma rays of energy from 30 MeV to about 10{sup 15} eV (since photons point to their places of origin), studies of the mass composition of cosmic rays (because it reflects source morphology), and studies of cosmic rays with energy above 1O{sup 19} eV (for these are the highest energies observed in nature). (author) 101 refs, 19 figs, 7 tabs

  11. Cosmic rays and molecular clouds

    OpenAIRE

    2012-01-01

    This paper deals with the cosmic-ray penetration into molecular clouds and with the related gamma--ray emission. High energy cosmic rays interact with the dense gas and produce neutral pions which in turn decay into two gamma rays. This makes molecular clouds potential sources of gamma rays, especially if they are located in the vicinity of a powerful accelerator that injects cosmic rays in the interstellar medium. The amplitude and duration in time of the cosmic--ray overdensity around a giv...

  12. Cosmic Ray Electron Science with GLAST

    Energy Technology Data Exchange (ETDEWEB)

    Ormes, J.F.; /Denver U.; Moiseev, Alexander; /NASA, Goddard

    2007-10-17

    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 {approx}20 to {approx}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.

  13. Glycosaminoglycan-mediated coacervation of tropoelastin abolishes the critical concentration, accelerates coacervate formation, and facilitates spherule fusion: implications for tropoelastin microassembly.

    Science.gov (United States)

    Tu, Yidong; Weiss, Anthony S

    2008-07-01

    Elastogenesis and elastin repair depend on the secretion of tropoelastin from the cell, yet cellular production is low in the many biological systems that have been studied. To address the apparent paradox of a paucity of tropoelastin for cell surface microassembly, we examined the effects of the glycosaminoglycans heparin, heparan sulfate, and chondroitin sulfate B, on tropoelastin aggregate formation through coacervation. We found a significant effect, particularly of heparin, on the minimum or critical concentration of tropoelastin, which was required for microassembly, lowering critical concentration to a point that it was no longer detectable. The assemblies resulted in protein droplet formation that was visually indistinguishable from the spherules that typify coacervation. The spherules readily coalesced in the presence of heparin and higher concentrations of tropoelastin, resulting in an almost continuous layer of coacervated tropoelastin. Four stages of droplet behavior were observed: early droplet formation, approximately 6 mum droplet formation, and fusion of droplets followed by the formation of a coalesced layer. We conclude that glycosaminoglycans in the extracellular matrix have the capacity to promote coacervation at low concentrations of tropoelastin.

  14. How large is the cosmic dust flux into the Earth's atmosphere?

    Science.gov (United States)

    Plane, John; Janches, Diego; Gomez-Martin, Juan Carlos; Bones, David; Diego Carrillo-Sanchez, Juan; James, Sandy; Nesvorny, David; Pokorny, Petr

    2016-07-01

    , ionization and radar detection can be used to compute the probability of detecting a specified meteoroid in the Arecibo beam; an upper limit to the cosmic dust input of 16 t d ^{-1} has been obtained from the radar observations. Underpinning this modelling work is a novel laboratory experiment at the University of Leeds, where a novel Meteor Ablation Simulator is used to study the evaporation of metals from cosmic dust particles that are flash heated to over 3000 K. Finally, rocket-borne measurements of charged meteoric smoke particles indicate that about 5 t d ^{-1} of this cosmic dust ablates in the atmosphere, and another 6 t d ^{-1} fall to the surface as cosmic spherules.

  15. The Emergence of Cosmic Education. Spotlight: Cosmic Education.

    Science.gov (United States)

    Trudeau, Sr. Christina Marie

    2002-01-01

    Discusses the influence of Hindu, Moslem, and Buddhist metaphysics on Maria Montessori's own pedagogical philosophy of Cosmic Education, which she regarded as the core of all learning experiences, after her visit to India. Considers the relationship between Montessori's ideas of child development and Cosmic Education, and the effect of Indian…

  16. Wormhole cosmic censorship

    Science.gov (United States)

    Matos, Tonatiuh; Ureña-López, L. Arturo; Miranda, Galaxia

    2016-05-01

    We analyze the properties of a Kerr-like wormhole supported by phantom matter, which is an exact solution of the Einstein-phantom field equations. It is shown that the solution has a naked ring singularity which is unreachable to null geodesics falling freely from the outside. Similarly to Roger Penrose's cosmic censorship, that states that all naked singularities in the Universe must be protected by event horizons, here we conjecture from our results that a naked singularity can also be fully protected by the intrinsic properties of a wormhole's throat.

  17. Cosmic baldness and stability

    Energy Technology Data Exchange (ETDEWEB)

    Panchapakesan, N.; Lohiya, D.

    1985-04-01

    The stability of the de Sitter metric and the relevance of the initial state of a domain which approaches a de Sitter universe asymptotically are investigated analytically, adapting the one-dimensional wave equation with effective potential derived by Khanal and Panchapakesan (1981), for the perturbations of the de Sitter-Schwarzschild metric, to the de Sitter case. It is demonstrated that initial nonspherical perturbations do not increase exponentially with time but rather decay, the frozen modes exponentially and the backscattered perturbations of finite angular momentum l as t to the -(2l - l). It is concluded that the cosmic horizon is stable and has no hair. 14 references.

  18. Wormhole cosmic strings

    CERN Document Server

    Clément, G

    1995-01-01

    We construct regular multi-wormhole solutions to a gravitating \\sigma model in three space-time dimensions, and extend these solutions to cylindrical traversable wormholes in four and five dimensions. We then discuss the possibility of identifying wormhole mouths in pairs to give rise to Wheeler wormholes. Such an identification is consistent with the original field equations only in the absence of the \\sigma-model source, but with possible naked cosmic string sources. The resulting Wheeler wormhole space-times are flat outside the sources and may be asymptotically Minkowskian.

  19. Pulsars: Cosmic Permanent 'Neutromagnets'?

    CERN Document Server

    Hansson, Johan

    2011-01-01

    We argue that pulsars may be spin-polarized neutron stars, i.e. cosmic permanent magnets. This would simply explain several observational facts about pulsars, including the 'beacon effect' itself i.e. the static/stable misalignment of rotational and magnetic axes, the extreme temporal stability of the pulses and the existence of an upper limit for the magnetic field strength - coinciding with the one observed in "magnetars". Although our model admittedly is speculative, this latter fact seems to us unlikely to be pure coincidence.

  20. Garden of cosmic speculation

    CERN Document Server

    Jencks, Charles

    2005-01-01

    This book tells the story of one of the most important gardens in Europe, created by the architectural critic and designer Charles Jencks and his late wife, the landscape architect and author Maggie Keswick. The Garden of Cosmic Speculation is a landscape that celebrates the new sciences of complexity and chaos theory and consists of a series of metaphors exploring the origins, the destiny and the substance of the Universe. The book is illustrated with year-round photography, bringing the garden's many dimensions vividly to life.

  1. Discovery of cosmic fractals

    CERN Document Server

    Baryshev, Yuri

    2002-01-01

    This is the first book to present the fascinating new results on the largest fractal structures in the universe. It guides the reader, in a simple way, to the frontiers of astronomy, explaining how fractals appear in cosmic physics, from our solar system to the megafractals in deep space. It also offers a personal view of the history of the idea of self-similarity and of cosmological principles, from Plato's ideal architecture of the heavens to Mandelbrot's fractals in the modern physical cosmos. In addition, this invaluable book presents the great fractal debate in astronomy (after Luciano Pi

  2. Spherules and IBV

    Science.gov (United States)

    Maier, Helena J; Hawes, Philippa C; Keep, Sarah M; Britton, Paul

    2014-01-01

    Infectious bronchitis virus (IBV) is an economically important virus infecting chickens, causing large losses to the poultry industry globally. While vaccines are available, there is a requirement for novel vaccine strategies due to high strain variation and poor cross-protection. This requires a more detailed understanding of virus-host cell interactions to identify candidates for targeted virus attenuation. One key area of research in the positive sense RNA virus field, due to its central role in virus replication, is the induction of cellular membrane rearrangements by this class of viruses for the assembly of virus replication complexes. In our recent work, we identified the structures induced by IBV during infection of cultured cells, as well as primary cells and ex vivo organ culture. We identified structures novel to the coronavirus family, which strongly resemble replication sites of other positive sense RNA viruses. We have begun to extend this work using recombinant IBVs, which are chimera of different virus strains to study the role of viral proteins in the induction of membrane rearrangements. PMID:25482229

  3. Cosmic Ray ^3He Measurements

    OpenAIRE

    Mewaldt, R. A.

    1985-01-01

    Cosmic ray ^3He/^4He observations, including a new measurement at ~65 MeV/nucleon from ISEE-3, are compared with interstellar propagation and solar modulation models in an effort to understand the origin of cosmic ray He nuclei.

  4. Self--gravitating cosmic rings

    OpenAIRE

    Clément, Gérard

    1998-01-01

    The classical Einstein--Maxwell field equations admit static horizonless wormhole solutions with only a circular cosmic string singularity. We show how to extend these static solutions to exact rotating asymptotically flat solutions. For a suitable range of parameter values, these solutions describe charged or neutral rotating closed cosmic strings, with a perimeter of the order of their Schwarzschild radius.

  5. George's cosmic treasure hunt

    CERN Document Server

    Hawking, Lucy; Parsons, Gary

    2009-01-01

    George and Annie explore the galaxy in this cosmic adventure from Stephen Hawking and Lucy Hawking, complete with essays from Professor Hawking about the latest in space travel. George is heartbroken when he learns that his friend Annie and her father are moving to the US. Eric has a new job working for the space program, looking for signs of life in the Universe. Eric leaves George with a gift—a book called The User’s Guide to the Universe. But Annie and Eric haven’t been gone for very long when Annie believes that she is being contacted by aliens, who have a terrible warning for her. George joins her in the US to help her with her quest—and before he knows it, he, Annie, Cosmos, and Annie’s annoying cousin Emmett have been swept up in a cosmic treasure hunt, spanning the whole galaxy and beyond. Lucy Hawking's own experiences in zero-gravity flight and interviews with astronauts at Cape Kennedy and the Johnson Space Center lend the book a sense of realism and excitement that is sure to fire up ima...

  6. Note on cosmic censorship

    Energy Technology Data Exchange (ETDEWEB)

    Tipler, F.J.

    1985-05-01

    A number of recent theorems by Krolak and Newman purport to prove cosmic censorship by showing that ''strong curvature'' singularities must be hidden behind horizons. It is proved that Newman's ''null, strong curvature'' condition, which is imposed on certain classes of null geodesics to restrict curvature growth in the space-time, does not hold in many physically realistic space-times: it is not satisfied by any null geodesic in the relevant class in any open Friedmann cosmological model, nor does it hold for any null geodesic in the relevant class in maximal Schwarzschild space. More generally, it is argued that the singularity predicted by the Penrose singularity theorem is unlikely to be of the type eliminated by Newman. Thus the Newman theorems are probably without physical significance. The Krolak theorems, although based on a physically significant definition of strong curvature singularity, are mathematically invalid, and this approach cannot be used to obtain a cosmic censorship theorem. (author).

  7. Evolution Of Cosmic Strings

    CERN Document Server

    Vanchurin, V

    2005-01-01

    We investigate the evolution of finite loops and infinite strings as a part of a complete cosmic string network. We give dynamical arguments showing that the structures on infinite strings should obey a scaling law. We perform a simulation of the network which uses functional forms for the string position and thus is exact to the limits of computer arithmetic. The effective box size of our simulation is at least two orders of magnitude larger than what was previously reached. Our results confirm that the wiggles on the strings obey a scaling law described by universal power spectrum. The average distance between long strings also scales accurately with the time. Production functions of string loops do not show scaling. With low intercommutation probability p the true scaling régime is not reached until very late cosmic times, which makes it difficult to simulate such evolutions. Via the expansion of the box technique, we were able to reach scaling with a wide range of p. The physical correlation ...

  8. Cosmic particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zimbardo, Gaetano; Perri, Silvia [Universita della Calabria, Dipartimento di Fisica, 87036 Rende (Italy)

    2014-07-01

    The most popular mechanism for the acceleration of cosmic rays, which is thought to operate in supernova remnant shocks as well as at heliospheric shocks, is the diffusive shock acceleration, which is a Fermi mechanism based on normal diffusion. On the other hand, in the last few years it has been shown that the transport of plasma particles in the presence of electric and magnetic turbulence can be superdiffusive rather than normal diffusive. The term 'superdiffusive' refers to the mean square displacement of particle positions growing superlinearly with time, as compared to the normal linear growth. In particular, superdiffusion is characterized by a non Gaussian statistical process called Levy random walk. We show how diffusive shock acceleration is modified by superdiffusion, and how this yields new predictions for the cosmic ray spectral index, for the acceleration time, and for the spatial profile of energetic particles. A comparison with observations of particle acceleration at heliospheric shocks and at supernova remnant shocks is done. We discuss how superdiffusive shock acceleration allows to explain the observations of hard ion spectra at the solar wind termination shock detected by Voyager 2, of hard radio spectra due to synchrotron emission of electrons accelerated at supernova remnant shocks, and how it can help to explain the observations of 'thin rims' in the X-ray synchrotron emission.

  9. Genuine cosmic hair

    Science.gov (United States)

    Kastor, David; Ray, Sourya; Traschen, Jennie

    2017-02-01

    We show that asymptotically future de Sitter (AFdS) spacetimes carry ‘genuine’ cosmic hair; information that is analogous to the mass and angular momentum of asymptotically flat spacetimes and that characterizes how an AFdS spacetime approaches its asymptotic form. We define new ‘cosmological tension’ charges associated with future asymptotic spatial translation symmetries, which are analytic continuations of the ADM mass and tensions of asymptotically planar AdS spacetimes, and which measure the leading anisotropic corrections to the isotropic, exponential de Sitter expansion rate. A cosmological Smarr relation, holding for AFdS spacetimes having exact spatial translation symmetry, is derived. This formula relates cosmological tension, which is evaluated at future infinity, to properties of the cosmology at early times, together with a ‘cosmological volume’ contribution that is analogous to the thermodynamic volume of AdS black holes. Smarr relations for different spatial directions imply that the difference in expansion rates between two directions at late times is related in a simple way to their difference at early times. Hence information about the very early universe can be inferred from cosmic hair, which is potentially observable in a late time de Sitter phase. Cosmological tension charges and related quantities are evaluated for Kasner–de Sitter spacetimes, which serve as our primary examples.

  10. L3 + Cosmics Experiment

    CERN Multimedia

    2002-01-01

    %RE4 %title\\\\ \\\\The L3+C experiment takes advantage of the unique properties of the L3 muon spectrometer to get an accurate measurement of cosmic ray muons 30 m underground. A new muon trigger, readout and DAQ system have been installed, as well as a scintillator array covering the upper surfaces of the L3 magnet for timing purposes. The acceptance amounts to 200 $m^2 sr$. The data are collected independently in parallel with L3 running. In spring 2000 a scintillator array will be installed on the roof of the SX hall in order to estimate the primary energy of air showers associated with events observed in L3+C.\\\\ \\\\The cosmic ray muon momentum spectrum, the zenith angular dependence and the charge ratio are measured with high accuracy between 20 and 2000 GeV/c. The results will provide new information about the primary composition, the shower development in the atmosphere, and the inclusive pion and kaon (production-) cross sections (specifically the "$\\pi$/K ratio") at high energies. These data will also hel...

  11. COSMIC monthly progress report

    Science.gov (United States)

    1994-01-01

    Activities of the Computer Software Management and Information Center (COSMIC) are summarized for the month of May 1994. Tables showing the current inventory of programs available from COSMIC are presented and program processing and evaluation activities are summarized. Nine articles were prepared for publication in the NASA Tech Brief Journal. These articles (included in this report) describe the following software items: (1) WFI - Windowing System for Test and Simulation; (2) HZETRN - A Free Space Radiation Transport and Shielding Program; (3) COMGEN-BEM - Composite Model Generation-Boundary Element Method; (4) IDDS - Interactive Data Display System; (5) CET93/PC - Chemical Equilibrium with Transport Properties, 1993; (6) SDVIC - Sub-pixel Digital Video Image Correlation; (7) TRASYS - Thermal Radiation Analyzer System (HP9000 Series 700/800 Version without NASADIG); (8) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (VAX VMS Version); and (9) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (UNIX Version). Activities in the areas of marketing, customer service, benefits identification, maintenance and support, and dissemination are also described along with a budget summary.

  12. Cosmic rays and global warming

    Energy Technology Data Exchange (ETDEWEB)

    Erlykin, A.D. [P.N. Lebedev Physical Institute, Moscow (Russian Federation); Sloan, T. [Lancaster University (United Kingdom); Wolfendale, A.W. [Durham University (United Kingdom)

    2010-07-01

    The possible effects of cosmic rays on clouds could contribute to global warming. The argument is that the observed increased solar activity during the last century caused a decrease in the ionization due to cosmic rays since the lower energy cosmic particles are deflected by the magnetic field created by the increasing solar wind. This would lead to a decrease in cloud cover allowing more heating of the earth by the sun. Meteorological data combined to solar activity observations and simulations show that any effect of solar activity on clouds and the climate is likely to be through irradiance rather than cosmic rays. Since solar irradiance transfers 8 orders of magnitude more energy to the atmosphere than cosmic rays it is more plausible that this can produce a real effect. The total contribution of variable solar activity to global warming is shown to be less than 14% of the total temperature rise. (A.C.)

  13. Transition from Galactic to extragalactic cosmic rays and cosmic ray anisotropy

    Directory of Open Access Journals (Sweden)

    Sigl G.

    2013-06-01

    Full Text Available This talk based on results of ref. [1], where 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(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. If the primary composition is mostly light or intermediate around E ∼ 1018 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >10 μG. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 1017 eV and 1018 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E > 1018 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.

  14. COSMIC: somatic cancer genetics at high-resolution

    Science.gov (United States)

    Forbes, Simon A.; Beare, David; Boutselakis, Harry; Bamford, Sally; Bindal, Nidhi; Tate, John; Cole, Charlotte G.; Ward, Sari; Dawson, Elisabeth; Ponting, Laura; Stefancsik, Raymund; Harsha, Bhavana; Kok, Chai Yin; Jia, Mingming; Jubb, Harry; Sondka, Zbyslaw; Thompson, Sam; De, Tisham; Campbell, Peter J.

    2017-01-01

    COSMIC, the Catalogue of Somatic Mutations in Cancer (http://cancer.sanger.ac.uk) is a high-resolution resource for exploring targets and trends in the genetics of human cancer. Currently the broadest database of mutations in cancer, the information in COSMIC is curated by expert scientists, primarily by scrutinizing large numbers of scientific publications. Over 4 million coding mutations are described in v78 (September 2016), combining genome-wide sequencing results from 28 366 tumours with complete manual curation of 23 489 individual publications focused on 186 key genes and 286 key fusion pairs across all cancers. Molecular profiling of large tumour numbers has also allowed the annotation of more than 13 million non-coding mutations, 18 029 gene fusions, 187 429 genome rearrangements, 1 271 436 abnormal copy number segments, 9 175 462 abnormal expression variants and 7 879 142 differentially methylated CpG dinucleotides. COSMIC now details the genetics of drug resistance, novel somatic gene mutations which allow a tumour to evade therapeutic cancer drugs. Focusing initially on highly characterized drugs and genes, COSMIC v78 contains wide resistance mutation profiles across 20 drugs, detailing the recurrence of 301 unique resistance alleles across 1934 drug-resistant tumours. All information from the COSMIC database is available freely on the COSMIC website. PMID:27899578

  15. Lagrangian methods of cosmic web classification

    Science.gov (United States)

    Fisher, J. D.; Faltenbacher, A.; Johnson, M. S. T.

    2016-05-01

    The cosmic web defines the large-scale distribution of matter we see in the Universe today. Classifying the cosmic web into voids, sheets, filaments and nodes allows one to explore structure formation and the role environmental factors have on halo and galaxy properties. While existing studies of cosmic web classification concentrate on grid-based methods, this work explores a Lagrangian approach where the V-web algorithm proposed by Hoffman et al. is implemented with techniques borrowed from smoothed particle hydrodynamics. The Lagrangian approach allows one to classify individual objects (e.g. particles or haloes) based on properties of their nearest neighbours in an adaptive manner. It can be applied directly to a halo sample which dramatically reduces computational cost and potentially allows an application of this classification scheme to observed galaxy samples. Finally, the Lagrangian nature admits a straightforward inclusion of the Hubble flow negating the necessity of a visually defined threshold value which is commonly employed by grid-based classification methods.

  16. Gravitational Waves and Light Cosmic Strings

    CERN Document Server

    Depies, Matthew R

    2009-01-01

    Gravitational wave signatures from cosmic strings are analyzed numerically. Cosmic string networks form during phase transistions in the early universe and these networks of long cosmic strings break into loops that radiate energy in the form of gravitational waves until they decay. The gravitational waves come in the form of harmonic modes from individual string loops, a "confusion noise" from galactic loops, and a stochastic background of gravitational waves from a network of loops. In this study string loops of larger size $\\alpha$ and lower string tensions $G\\mu$ (where $\\mu$ is the mass per unit length of the string) are investigated than in previous studies. Several detectors are currently searching for gravitational waves and a space based satellite, the Laser Interferometer Space Antenna (LISA), is in the final stages of pre-flight. The results for large loop sizes ($\\alpha=0.1$) put an upper limit of about $G\\mu<10^{-9}$ and indicate that gravitational waves from string loops down to $G\\mu \\approx...

  17. Measurement of cosmic-ray muons with the Distributed Electronic Cosmic-ray Observatory, a network of smartphones

    Science.gov (United States)

    Vandenbroucke, J.; BenZvi, S.; Bravo, S.; Jensen, K.; Karn, P.; Meehan, M.; Peacock, J.; Plewa, M.; Ruggles, T.; Santander, M.; Schultz, D.; Simons, A. L.; Tosi, D.

    2016-04-01

    Solid-state camera image sensors can be used to detect ionizing radiation in addition to optical photons. We describe the Distributed Electronic Cosmic-ray Observatory (DECO), an app and associated public database that enables a network of consumer devices to detect cosmic rays and other ionizing radiation. In addition to terrestrial background radiation, cosmic-ray muon candidate events are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular distribution of muons at sea level. We use a sample of candidate muon events detected by DECO to measure the thickness of the depletion region of the camera image sensor in a particular consumer smartphone model, the HTC Wildfire S. The track length distribution is fit better by a cosmic-ray muon angular distribution than an isotropic distribution, demonstrating that DECO can detect and identify cosmic-ray muons despite a background of other particle detections. Using the cosmic-ray distribution, we measure the depletion thickness to be 26.3 ± 1.4 μm. With additional data, the same method can be applied to additional models of image sensor. Once measured, the thickness can be used to convert track length to incident polar angle on a per-event basis. Combined with a determination of the incident azimuthal angle directly from the track orientation in the sensor plane, this enables direction reconstruction of individual cosmic-ray events using a single consumer device. The results simultaneously validate the use of cell phone camera image sensors as cosmic-ray muon detectors and provide a measurement of a parameter of camera image sensor performance which is not otherwise publicly available.

  18. Cosmic Christ in a Quantum Universe.

    Science.gov (United States)

    Kohli, Mary Ann

    This study examines the figure of the second American Adam--the cosmic Christ archetype--in terms of a possible shift in the focus of Western consciousness. As science moves closer to religion and as Newtonian dualism gives way to a more holistic theory (in which observer, observed, and process of observation are all intricately interlinked), the cosmic Christ emerges as a symbol in contemporary American fiction of a potentially unified awareness which could reconnect post-Christian man to God, to the world, and to the self. Such a rebirth of unity would be contingent upon the death of a consciousness reliant upon the rational, linear, masculine, left-brained thinking associated with the old Newtonian paradigm. The resurrected consciousness would consolidate Eastern and Western religion by acknowledging the God within man through the Western symbology of the Christ prototype. It would also balance the intuitional with the rational, the cyclical with the linear, the feminine with the masculine, and the right brain with the left. In other words, the repressed elements of the collective Western psyche would be allowed to come to awareness and be integrated into the mind at large. This integrating process is implicit in the cosmic Christ imagery. The novels which are considered are all concerned with the role of consciousness in the postmodern world and the part that science and religion play in determining the nature of that role. In such varied works as Thomas Pynchon's Gravity's Rainbow, John Updike's Roger's Version, Saul Bellow's Herzog, Joan Didion's A Book of Common Prayer, and William Vollmann's The Ice-Shirt, a cosmic Christ figure invariably appears. The success of this figure, however, is ambiguous and uncertain. At best, the transition of consciousness that is achieved is individual rather than communal. Nevertheless, as chaos theory has demonstrated, small changes can bring about major effects. Consequently, both the science of today and the rapid growth

  19. Cosmic ray driven Galactic winds

    CERN Document Server

    Recchia, S; Morlino, G

    2016-01-01

    The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas from the Galaxy, thereby regulating several physical processes, including star formation. The dynamics of these cosmic ray driven winds is intrinsically non-linear in that the spectrum of cosmic rays determines the characteristics of the wind (velocity, pressure, magnetic field) and in turn the wind dynamics affects the cosmic ray spectrum. Moreover, the gradient of the cosmic ray distribution function causes excitation of Alfven waves, that in turn determine the scattering properties of cosmic rays, namely their diffusive transport. These effects all feed into each other so that what we see at the Earth is the result of these non-linear effects. Here we investigate the launch and evolution of such winds, and we determine the impli...

  20. Cosmic magnetic fields

    CERN Document Server

    Kronberg, Philipp P

    2016-01-01

    Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.

  1. Microphysics of cosmic plasmas

    CERN Document Server

    Bykov, Andrei; Cargill, Peter; Dendy, Richard; Wit, Thierry; Raymond, John

    2014-01-01

    This title presents a review of the detailed aspects of the physical processes that underlie the observed properties, structures and dynamics of cosmic plasmas. An assessment of the status of understanding of microscale processes in all astrophysical collisionless plasmas is provided. The topics discussed include  turbulence in astrophysical and solar system plasmas as a phenomenological description of their dynamic properties on all scales; observational, theoretical and modelling aspects of collisionless magnetic reconnection; the formation and dynamics of shock waves; and a review and assessment of microprocesses, such as the hierarchy of plasma instabilities, non-local and non-diffusive transport processes and ionisation and radiation processes.  In addition, some of the lessons that have been learned from the extensive existing knowledge of laboratory plasmas as applied to astrophysical problems are also covered.   This volume is aimed at graduate students and researchers active in the areas of cosmi...

  2. Cosmic Ray Antimatter

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Over the last decade, space-born experiments have delivered new measurements of high energy cosmic-ray (CR) antiprotons and positrons, opening new frontiers in energy reach and precision. While being a promising discovery tool for new physics or exotic astrophysical phenomena, an irreducible background of antimatter comes from CR collisions with interstellar matter in the Galaxy. Understanding this irreducible source or constraining it from first principles is an interesting challenge: a game of hide-and-seek where the objective is to identify the laws of basic particle physics among the forest of astrophysical uncertainties. I describe an attempt to obtain such understanding, combining information from a zoo of CR species including massive nuclei and relativistic radioisotopes. I show that: (i) CR antiprotons most likely come from CR-gas collisions; (ii) positron data is consistent with, and suggestive of the same astrophysical production mechanism responsible for antiprotons and dominated by proton-proton c...

  3. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  4. Acceleration of cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation)], E-mail: berezhko@ikfia.ysn.ru

    2008-07-15

    Cosmic ray (CR) origin problem is briefly discussed. It is argued that CRs with energies up to 10{sup 17} eV are produced in galactic supernova remnants, whereas ultra high energy CRs are extragalactic. CR composition strongly changes within the transition from galactic to extragalactic CR component, therefore precise measurements of CR composition at energies 10{sup 17} - 10{sup 19} eV are needed for the reliable determination of this transition. The possible sources of extragalactic CRs are briefly discussed. It is argued that CR acceleration at the shock created by the expanding cocoons around active galactic nuclei has to be considered as a prime candidate for the sources of extragalactic CRs.

  5. Cosmic string loop shapes

    CERN Document Server

    Blanco-Pillado, Jose J; Shlaer, Benjamin

    2015-01-01

    We analyze the shapes of cosmic string loops found in large-scale simulations of an expanding-universe string network. The simulation does not include gravitational back reaction, but we model that process by smoothing the loop using Lorentzian convolution. We find that loops at formation consist of generally straight segments separated by kinks. We do not see cusps or any cusp-like structure at the scale of the entire loop, although we do see very small regions of string that move with large Lorentz boosts. However, smoothing of the string almost always introduces two cusps on each loop. The smoothing process does not lead to any significant fragmentation of loops that were in non-self-intersecting trajectories before smoothing.

  6. Simulating Cosmic Structure Formation

    CERN Document Server

    Weinberg, D H; Hernquist, L E; Weinberg, David H.; Katz, Neal; Hernquist, Lars

    1997-01-01

    We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body simulations with Gaussian initial conditions produce a pattern of sheets, filaments, tunnels, and voids that resembles the observed large scale galaxy distribution. Simulations that incorporate gas dynamics and dissipation form dense clumps of cold gas with sizes and masses similar to the luminous parts of galaxies. Models based on inflation and cold dark matter predict a healthy population of high redshift galaxies, including systems with star formation rates of 20 M_{\\sun}/year at z=6. At z~3, most of the baryons in these models reside in the low density intergalactic medium, which produces fluctuating Lyman-alpha absorption in the spectra of background quasars. The physical description of this ``Lyman-alpha forest'' is particularly simple if the absorption spectrum is viewe...

  7. Cosmic Light EDU kit

    Science.gov (United States)

    Doran, Rosa

    2015-08-01

    In 2015 we celebrate the International Year of Light, a great opportunity to promote awareness about the importance of light coming from the Cosmos and what messages it is bringing to mankind. In parallel a unique moment to attract the attention of stakeholders on the dangers of light pollution and its impact in our lives and our pursuit of more knowledge. In this presentation I want to present one of the conrnerstones of IYL2015, a partnership between the Galileo Teacher Training Program, Universe Awareness and Globe at Night, the Cosmic Light EDU kit. The aim of this project is to assemble a core set of tools and resources representing our basic knowledge pilars about the Universe and simple means to preserve our night sky.

  8. On Strong Cosmic Censorship

    CERN Document Server

    Isenberg, James

    2015-01-01

    For almost half of the one hundred year history of Einstein's theory of general relativity, Strong Cosmic Censorship has been one of its most intriguing conjectures. The SCC conjecture addresses the issue of the nature of the singularities found in most solutions of Einstein's gravitational field equations: Are such singularities generically characterized by unbounded curvature? Is the existence of a Cauchy horizon (and the accompanying extensions into spacetime regions in which determinism fails) an unstable feature of solutions of Einstein's equations? In this short review article, after briefly commenting on the history of the SCC conjecture, we survey some of the progress made in research directed either toward supporting SCC or toward uncovering some of its weaknesses. We focus in particular on model versions of SCC which have been proven for restricted families of spacetimes (e.g., the Gowdy spacetimes), and the role played by the generic presence of Asymptotically Velocity Term Dominated behavior in th...

  9. Cosmic ray synergies

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    In laboratories, cosmic rays have been the subject of scientific research for many years. A more recent development is their appearance in schools, as educational tools. A recent workshop at CERN, organised by ASPERA in collaboration with EPPOG and EPPCN, had the goal of bringing together ideas and initiatives with a view to setting up a future common project.   Presentation at the workshop on 15 October. In research, as in education, you can sometimes get things done more rapidly and easily by joining forces. For roughly the past decade, physicists have been taking their particle detectors to secondary schools. “The challenge now is to bring all of these existing projects together in a network,” says Arnaud Marsollier, in charge of communication for the ASPERA network and organiser of the workshop. The workshop held on Friday, 15 October was attended by representatives of major European educational projects and members of the European Particle Physics Communication Network...

  10. Genuine Cosmic Hair

    CERN Document Server

    Kastor, David; Traschen, Jennie

    2016-01-01

    We show that asymptotically future deSitter (AFdS) spacetimes carry 'genuine' cosmic hair; information that is analogous to the mass and angular momentum of asymptotically flat spacetimes and that characterizes how an AFdS spacetime approaches its asymptotic form. We define new 'cosmological tension' charges associated with future asymptotic spatial translation symmetries, which are analytic continuations of the ADM mass and tensions of asymptotically planar AdS spacetimes, and which measure the leading anisotropic corrections to the isotropic, exponential deSitter expansion rate. A cosmological Smarr relation, holding for AFdS spacetimes having exact spatial translation symmetry, is derived. This formula relates cosmological tension, which is evaluated at future infinity, to properties of the cosmology at early times, together with a 'cosmological volume' contribution that is analogous to the thermodynamic volume of AdS black holes. Smarr relations for different spatial directions imply that the difference i...

  11. THE COSMIC ORIGINS SPECTROGRAPH

    Energy Technology Data Exchange (ETDEWEB)

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John [Department of Astrophysical and Planetary Sciences, University of Colorado, 391-UCB, Boulder, CO 80309 (United States); Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin [Center for Astrophysics and Space Astronomy, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Ebbets, Dennis [Ball Aerospace and Technologies Corp., 1600 Commerce Street, Boulder, CO 80301 (United States); Heap, Sara H. [NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771 (United States); Leitherer, Claus; Sembach, Kenneth [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, Boulder, CO 80309-0440 (United States); Savage, Blair D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Siegmund, Oswald H. W. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Spencer, John; Alan Stern, S. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Welsh, Barry [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  12. The Cosmic Origins Spectrograph

    Science.gov (United States)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; Siegmund, Oswald H. W.; Snow, Theodore P.; Spencer, John; Stern, S. Alan; Stocke, John; Welsh, Barry; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Keeney, Brian; McPhate, Jason; Penton, Steven V; Andrews, John; Morse, Jon

    2010-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  13. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    Farook Rahaman; Subenoy Chakraborty; K Maity

    2002-01-01

    We present a detailed analysis of the motion of test particle in the gravitational field of cosmic strings in different situations using the Hamilton–Jacobi (H–J) formalism. We have discussed the trajectories near static cosmic string, cosmic string in Brans–Dicke theory and cosmic string in dilaton gravity.

  14. A cosmic microwave background feature consistent with a cosmic texture.

    Science.gov (United States)

    Cruz, M; Turok, N; Vielva, P; Martínez-González, E; Hobson, M

    2007-12-07

    The Cosmic Microwave Background provides our most ancient image of the universe and our best tool for studying its early evolution. Theories of high-energy physics predict the formation of various types of topological defects in the very early universe, including cosmic texture, which would generate hot and cold spots in the Cosmic Microwave Background. We show through a Bayesian statistical analysis that the most prominent 5 degrees -radius cold spot observed in all-sky images, which is otherwise hard to explain, is compatible with having being caused by a texture. From this model, we constrain the fundamental symmetry-breaking energy scale to be (0) approximately 8.7 x 10(15) gigaelectron volts. If confirmed, this detection of a cosmic defect will probe physics at energies exceeding any conceivable terrestrial experiment.

  15. Spherical Orbifolds for Cosmic Topology

    CERN Document Server

    Kramer, Peter

    2012-01-01

    Harmonic analysis is a tool to infer cosmic topology from the measured astrophysical cosmic microwave background CMB radiation. For overall positive curvature, Platonic spherical manifolds are candidates for this analysis. We combine the specific point symmetry of the Platonic manifolds with their deck transformations. This analysis in topology leads from manifolds to orbifolds. We discuss the deck transformations of the orbifolds and give basis functions for the harmonic analysis as linear combinations of Wigner polynomials on the 3-sphere. They provide new tools for detecting cosmic topology from the CMB radiation.

  16. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability...... in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...... in cosmic ray intensities. Such changes are in agreement with the sign of cloud radiative forcing associated with cosmic ray variability as estimated from satellite observations....

  17. Cosmic Ray Acceleration by Supernova Shocks

    CERN Document Server

    Berezhko, E G

    2008-01-01

    We analyse the results of recent measurements of nonthermal emission from individual supernova remnants (SNRs) and their correspondence to the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is shown that the theory fits these data in a satisfactory way and provides the strong evidences for the efficient CR production in SNRs accompanied by significant magnetic field amplification. Magnetic field amplification leads to considerable increase of CR maximum energy so that the spectrum of CRs accelerated in SNRs is consistent with the requirements for the formation of Galactic CR spectrum up to the energy ~10^17 eV.

  18. Dark matter and cosmic structure

    OpenAIRE

    2012-01-01

    We review the current standard model for the evolution of cosmic structure, tracing its development over the last forty years and focusing specifically on the role played by numerical simulations and on aspects related to the nature of dark matter.

  19. Inhomogeneous recombinations during cosmic reionization

    OpenAIRE

    Sobacchi, Emanuele; Mesinger, Andrei

    2014-01-01

    By depleting the ionizing photon budget available to expand cosmic HII regions, recombining systems (or Lyman limit systems) can have a large impact during (and following) cosmic reionization. Unfortunately, directly resolving such structures in large-scale reionization simulations is computationally impractical. Instead, here we implement a sub-grid prescription for tracking inhomogeneous recombinations in the intergalactic medium. Building on previous work parameterizing photo-heating feedb...

  20. Cosmic rays from thermal sources

    CERN Document Server

    Wlodarczyk, Z

    2007-01-01

    The energy spectrum of cosmic rays (CR) exhibits very characteristic power-like behavior with the "knee" structure. We consider a generalized statistical model for the production process of cosmic rays which accounts for such behavior in a natural way either by assuming the existence of temperature fluctuations in the source of CR, or by assuming specific temperature distribution of the CR sources. Both possibilities yield the so called Tsallis statistics and lead to the power-like distribution.

  1. Cosmic rays and Earth's climate

    DEFF Research Database (Denmark)

    Svensmark, Henrik

    2000-01-01

    During the last solar cycle the Earth's cloud cover underwent a modulation in phase with the cosmic ray flux. Assuming that there is a causal relationship between the two, it is expected and found that the Earth's temperature follows more closely decade variations in cosmic ray flux than other...... solar activity parameters. If the relationship is real the state of the Heliosphere affects the Earth's climate....

  2. Calculation of cosmic ray induced single event upsets: Program CRUP (Cosmic Ray Upset Program)

    Science.gov (United States)

    Shapiro, P.

    1983-09-01

    This report documents PROGRAM CRUP, COSMIC RAY UPSET PROGRAM. The computer program calculates cosmic ray induced single-event error rates in microelectronic circuits exposed to several representative cosmic-ray environments.

  3. Cosmic Rays and Particle Physics

    Science.gov (United States)

    Gaisser, Thomas K.; Engel, Ralph; Resconi, Elisa

    2016-06-01

    Preface to the first edition; Preface to the second edition; 1. Cosmic rays; 2. Cosmic ray data; 3. Particle physics; 4. Hadronic interactions and accelerator data; 5. Cascade equations; 6. Atmospheric muons and neutrinos; 7. Neutrino masses and oscillations; 8. Muons and neutrinos underground; 9. Cosmic rays in the Galaxy; 10. Extragalactic propagation of cosmic rays; 11. Astrophysical - rays and neutrinos; 12. Acceleration; 13. Supernovae in the Milky Way; 14. Astrophysical accelerators and beam dumps; 15. Electromagnetic cascades; 16. Extensive air showers; 17. Very high energy cosmic rays; 18. Neutrino astronomy; A.1. Units, constants and definitions; A.2. References to flux measurements; A.3. Particle flux, density, and interaction cross section; A.4. Fundamentals of scattering theory; A.5. Regge amplitude; A.6. Glauber model of nuclear cross sections; A.7. Earth's atmosphere; A.8. Longitudinal development of air showers; A.9. Secondary positrons and electrons; A.10. Liouville's theorem and cosmic ray propagation; A.11. Cosmology and distances measures; A.12. The Hillas splitting algorithm; References; Index.

  4. Cosmic Microwave Background Mapping

    Science.gov (United States)

    Verkhodanov, O. V.; Doroshkevich, A. G.

    2012-03-01

    The last decade of research in cosmology was connected with the ambitious experiments including space and ground base observations. Among the most impressive results of these investigations are the measurements of the cosmic microwave background (CMB) radiation like WMAP* and Planck. Exactly from the CMB studies, we have started the epoch of the precision cosmology when generally the values of cosmological parameters have been known and present research is devoted to improvement of the precision. These achievements are connected with both the creation of the new facilities in millimeter and submillimeter astronomy (e.g., satellites, receivers, antennas, computers) and development of the methods for the CMB data analysis. Actually, the process of data analysis contains several technical stages including 1. Registration of time-ordered data (TOD) 2. Pixelization of the CMB data - map preparation 3. Component separation 4. Map statistics analysis 5. Map - spherical harmonics transformation 6. C(l)-spectrum calculation and spectrum statistics analysis 7. Cosmological parameters estimation Starting from the cosmic background explorer (COBE) experiment using the so-called Quadrilateralized Sky Cube Projection (see [1-3]), the problem of the whole sky CMB pixelization has attracted great interest and many such schemes were developed. Let us note however that accurate pixelization of the CMB data on the sphere is very important but not the final step of analysis. Usually, the next step implies the determination of the coefficients of the spherical harmonic decomposition of the CMB signal for both anisotropy and polarization. This means that some of the pixelization schemes provide a very accurate map but are inconvenient for further decomposition. This also means that the choice of suitable pixelization schemes depends upon the general goals of the investigation. In this review, we consider several of the most popular sky map pixelization schemes and link them with the

  5. Illustrated cosmic monopole

    CERN Document Server

    Seagrave, Wyken

    2015-01-01

    Truly bizarre, utterly unique I've never read a novel quite like this before. The author takes you on an exciting adventure full of unforgettable and vivid imagery. Solidly written with each character's personality shining through. If you find physics fascinating you will not be disappointed by the author's keen intellect and clear understanding of this most challenging (for me anyway) scientific subject. This is not a novel I will forget anytime soon, I would highly recommend it. Andrewly Very imaginative tale Anybody interested in a very imaginative and engrossing sci fi story needs to check this one out. I have been reading sci fi for decades and this story has elements that surprise me which is very unusual considering the number of novels and stories I have over the years. ric freeman Summary of the story The cosmic monopole has been wandering the Universe since it was created in the Big Bang. Its existence is fundamental to the way the Universe works. It is finally trapped by the powerful magnetic f...

  6. Cosmic string loop microlensing

    Science.gov (United States)

    Bloomfield, Jolyon K.; Chernoff, David F.

    2014-06-01

    Cosmic superstring loops within the galaxy microlens background point sources lying close to the observer-string line of sight. For suitable alignments, multiple paths coexist and the (achromatic) flux enhancement is a factor of two. We explore this unique type of lensing by numerically solving for geodesics that extend from source to observer as they pass near an oscillating string. We characterize the duration of the flux doubling and the scale of the image splitting. We probe and confirm the existence of a variety of fundamental effects predicted from previous analyses of the static infinite straight string: the deficit angle, the Kaiser-Stebbins effect, and the scale of the impact parameter required to produce microlensing. Our quantitative results for dynamical loops vary by O(1) factors with respect to estimates based on infinite straight strings for a given impact parameter. A number of new features are identified in the computed microlensing solutions. Our results suggest that optical microlensing can offer a new and potentially powerful methodology for searches for superstring loop relics of the inflationary era.

  7. Cosmic ray driven outflows

    CERN Document Server

    Hanasz, Michal; Naab, Thorsten; Gawryszczak, Artur; Kowalik, Kacper; Wóltański, Dominik

    2013-01-01

    We present simulations of the magnetized interstellar medium (ISM) in models of massive star forming (40 Msun / yr) disk galaxies with high gas surface densities (~100 Msun / pc^2) similar to observed star forming high-redshift disks. We assume that type II supernovae deposit 10 per cent of their energy into the ISM as cosmic rays and neglect the additional deposition of thermal energy or momentum. With a typical Galactic diffusion coefficient for CRs (3e28 cm^2 / s) we demonstrate that this process alone can trigger the local formation of a strong low density galactic wind maintaining vertically open field lines. Driven by the additional pressure gradient of the relativistic fluid the wind speed can exceed 1000 km/s, much higher than the escape velocity of the galaxy. The global mass loading, i.e. the ratio of the gas mass leaving the galactic disk in a wind to the star formation rate becomes of order unity once the system has settled into an equilibrium. We conclude that relativistic particles accelerated i...

  8. Cosmic Ray Helium Hardening

    CERN Document Server

    Ohira, Yutaka

    2010-01-01

    Recent observations by CREAM, ATIC-2 and PAMELA experiments suggest that (1) the spectrum of cosmic ray (CR) helium is harder than that of CR proton below the knee $10^15 eV$ and (2) all CR spectra become hard at $\\gtrsim 10^{11} eV/n$. We propose a new picture that higher energy CRs are generated in more helium-rich region to explain the hardening (1) without introducing different sources for CR helium. The helium to proton ratio at $\\sim 100$ 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 the chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium when escaping from the supernova remnant (SNR) shock. We provide a simple analytical spectrum that also fits well the hardening (2) because of the decreasing Mach number in the hot superbubble with $\\sim 10^6$ K. Our model predicts hard and con...

  9. The Cosmic Origins Spectrograph

    CERN Document Server

    Green, James C; Osterman, Steve; Ebbets, Dennis; Heap, Sara H; Linsky, Claus Leitherer Jeffrey L; Savage, Blair D; Sembach, Kenneth; Shull, J Michael; Siegmund, Oswald H W; Snow, Theodore P; Spencer, John; Stern, S Alan; Stocke, John; Welsh, Barry; Beland, Stephane; Burgh, Eric B; Danforth, Charles; France, Kevin; Keeney, Brian; McPhate, Jason; Penton, Steven V; Andrews, John; Brownsberger, Kenneth; Morse, Jon; Wilkinson, Erik

    2011-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F_lambda ~ 1.0E10-14 ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011....

  10. Cosmic ray composition investigations using ICE/ISEE-3

    Science.gov (United States)

    Wiedenbeck, Mark E.

    1992-01-01

    The analysis of data from the high energy cosmic experiment on ISEE-3 and associated modeling and interpretation activities are discussed. The ISEE-3 payload included two instruments capable of measuring the composition of heavy cosmic rays. The designs of these two instruments incorporated innovations which made it possible, for the first time, to measure isotopic as well as the chemical composition for a wide range of elements. As the result of the demonstrations by these two instruments of the capability to resolve individual cosmic ray isotopes, a new generation of detectors was developed using very similar designs, but having improved reliability and increased sensitive area. The composition measurements which were obtained from the ISEE-3 experiment are summarized.

  11. Cosmic web imager

    Science.gov (United States)

    Rahman, Shahinur; Martin, Chris; McLean, Ryan; Matuszewski, Matt; Chang, Daphne

    2006-06-01

    We are developing the Cosmic Web Imager (CWI) to detect and map emission from the intergalactic medium (IGM). CWI will observe the strong, redshift UV resonance lines of Lyα 1216, CIV 1550, and OVI 1033 over 3600-9000 Å to trace IGM at 1 view of 60 × 40 arcsec2 for observing extended emission over a large region. The spectrograph using Volume-Phase Holographic gratings have high peak diffraction efficiency and are tunable for covering a large bandpass with a single grating. A low read noise CCD combined with source/background shiftand-nod allowing control of systematics and Poisson-imited sky subtraction to observe the low surface brightness universe. With a resolution of R=10,000 CWI is sensitive to limiting surface brightness ranging from 25 - 27.5 mag/arcsec2 (10 min - 8 hours integration). Recent high resolution simulations predict Lyα Fluorescence from IGM at 100 - 1000 LU1. CWI with sensitivity of ~200 LU improves the current observational effort by an order of magnitude and enables us to explore wide range of overdensity (δ ~ 30 - 104) testing the standard model of structure formation in the universe. CWI also serves as the counter part to the balloon borne integral-field spectrograph Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL) currently being built and planned to be launched in Summer 2007. FIREBALL will observe Lyα Fluorescence from IGM at z = 0.7. CWI combined with FIREBALL will enable us to observe the evolution of IGM and the low surface brightness universe.

  12. Cosmic radiation algorithm utilizing flight time tables

    Energy Technology Data Exchange (ETDEWEB)

    Katja Kojo, M.Sc.; Mika Helminen, M.Sc.; Anssi Auvinen, M.D.Ph.D. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Katja Kojo, M.Sc.; Anssi Auvinen, M.D.Ph.D. [Tampere Univ., School of Public Health (Finland); Gerhard Leuthold, D.Sc. [GSF - Research Center, Institute of Radiation Protection, Neuherberg (Germany)

    2006-07-01

    Cosmic radiation is considerably higher on cruising altitudes used in aviation than at ground level. Exposure to cosmic radiation may increase cancer risk among pilots and cabin crew. The International Commission on Radiation Protection (ICRP) has recommended that air crew should be classified as radiation workers. Quantification of cosmic radiation doses is necessary for assessment of potential health effects of such occupational exposure. For Finnair cabin crew (cabin attendants and stewards), flight history is not available for years prior to 1991 and therefore, other sources of information on number and type of flights have to be used. The lack of systematically recorded information is a problem for dose estimation for many other flight companies personnel as well. Several cosmic radiation dose estimations for cabin crew have been performed using different methods (e.g. 2-5), but they have suffered from various shortcomings. Retrospective exposure estimation is not possible with personal portable dosimeters. Methods that employ survey data for occupational dose assessment are prone to non-differential measurement error i.e. the cabin attendants do not remember correctly the number of past flights. Assessment procedures that utilize surrogate measurement methods i.e. the duration of employment, lack precision. The aim of the present study was to develop an assessment method for individual occupational exposure to cosmic radiation based on flight time tables. Our method provides an assessment method that does not require survey data or systematic recording of flight history, and it is rather quick, inexpensive, and possible to carry out in all other flight companies whose past time tables for the past periods exist. Dose assessment methods that employ survey data are prone to random error i.e. the cabin attendants do not remember correctly the number or types of routes that they have flown during the past. Our method avoids this since survey data are not needed

  13. Some doubts concerning a link between cosmic ray fluxes and global cloudiness

    Science.gov (United States)

    Kernthaler, Simon C.; Toumi, Ralf; Haigh, Joanna D.

    Svensmark and Friis-Christensen (1997, henceforth SFC) showed a strong correlation between cosmic ray flux and ISCCP total cloudiness between 1984 and 1990. They concluded that ionisation by cosmic rays, more prevalent at times of lower solar activity, might explain apparent correlations between solar activity and climate through changes in cloud radiative forcing. We have extended SFC's approach with a study of the different cloud types, restricting our analysis to the period 1985 to 1988 during which the ISCCP calibration is believed to be stable. We find no clear relationship between individual cloud types and cosmic ray flux. Inclusion of data at high latitudes decreases the amplitude of the apparent correlation although ionisation by cosmic rays is greatest at high latitudes. Thin high cloud shows an increase throughout the period such that the combined effect of the changes in cloud types suggests an almost monotonic increase in cloud radiative forcing between 1985 and 1988 which is not related to cosmic ray activity.

  14. Nearby supernova remnants and the cosmic-ray spectral hardening at high energies

    CERN Document Server

    Thoudam, Satyendra

    2011-01-01

    Recent measurements of cosmic-ray spectra of several individual nuclear species by the CREAM, TRACER, and ATIC experiments indicate a change in the spectral index of the power laws at TeV energies. Possible explanations among others include non linear diffusive shock acceleration of cosmic-rays, different cosmic-ray propagation properties at higher and lower energies in the Galaxy and the presence of nearby sources. In this paper, we show that if supernova remnants are the main sources of cosmic rays in our Galaxy, the effect of the nearby remnants can be responsible for the observed spectral changes. Using a rigidity dependent escape of cosmic-rays from the supernova remnants, we explain the apparent observed property that the hardening of the helium spectrum occurs at relatively lower energies as compared to the protons and also that the spectral hardening does not persist beyond $\\sim (20-30)$ TeV energies.

  15. Cosmic logic: a computational model

    Science.gov (United States)

    Vanchurin, Vitaly

    2016-02-01

    We initiate a formal study of logical inferences in context of the measure problem in cosmology or what we call cosmic logic. We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or Gödel number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies that it is impossible to construct CM machines to compute probabilities on the set of all CO machines using cut-off prescriptions. The cut-off measures can still be used if the set is reduced to include only machines which halt after a finite and predetermined number of steps.

  16. Cosmic-ray exposure ages of chondrules

    Science.gov (United States)

    Roth, Antoine S. G.; Metzler, Knut; Baumgartner, Lukas P.; Leya, Ingo

    2016-07-01

    If chondrules were exposed to cosmic rays prior to meteorite compaction, they should retain an excess of cosmogenic noble gases. Beyersdorf-Kuis et al. (2015) showed that such excesses can be detected provided that the chemical composition of each individual chondrule is precisely known. However, their study was limited to a few samples as they had to be irradiated in a nuclear reactor for instrumental neutron activation analysis. We developed a novel analytical protocol that combines the measurements of He and Ne isotopic concentrations with a fast method to correct for differences in chemical composition using micro X-ray computed tomography. Our main idea is to combine noble gas, nuclear track, and petrography data for numerous chondrules to understand the precompaction exposure history of the chondrite parent bodies. Here, we report our results for a total of 77 chondrules and four matrix samples from NWA 8276 (L3.00), NWA 8007 (L3.2), and Bjurböle (L/LL4). All chondrules from the same meteorite have within uncertainty identical 21Ne exposure ages, and all chondrules from Bjurböle have within uncertainty identical 3He exposure ages. However, most chondrules from NWA 8276 and a few from NWA 8007 show small but resolvable differences in 3He exposure age that we attribute to matrix contamination and/or gas loss. The finding that none of the chondrules has noble gas excesses is consistent with the uniform track density found for each meteorite. We conclude that the studied chondrules did not experience a precompaction exposure longer than a few Ma assuming present-day flux of galactic cosmic rays. A majority of chondrules from L and LL chondrites thus rapidly accreted and/or was efficiently shielded from cosmic rays in the solar nebula.

  17. Turning Around along the Cosmic Web

    Science.gov (United States)

    Lee, Jounghun; Yepes, Gustavo

    2016-12-01

    A bound violation designates a case in which the turnaround radius of a bound object exceeds the upper limit imposed by the spherical collapse model based on the standard ΛCDM paradigm. Given that the turnaround radius of a bound object is a stochastic quantity and that the spherical model overly simplifies the true gravitational collapse, which actually proceeds anisotropically along the cosmic web, the rarity of the occurrence of a bound violation may depend on the web environment. Assuming a Planck cosmology, we numerically construct the bound-zone peculiar velocity profiles along the cosmic web (filaments and sheets) around the isolated groups with virial mass {M}{{v}}≥slant 3× {10}13 {h}-1 {M}⊙ identified in the Small MultiDark Planck simulations and determine the radial distances at which their peculiar velocities equal the Hubble expansion speed as the turnaround radii of the groups. It is found that although the average turnaround radii of the isolated groups are well below the spherical bound limit on all mass scales, the bound violations are not forbidden for individual groups, and the cosmic web has an effect of reducing the rarity of the occurrence of a bound violation. Explaining that the spherical bound limit on the turnaround radius in fact represents the threshold distance up to which the intervention of the external gravitational field in the bound-zone peculiar velocity profiles around the nonisolated groups stays negligible, we discuss the possibility of using the threshold distance scale to constrain locally the equation of state of dark energy.

  18. Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago.

    Science.gov (United States)

    Bunch, Ted E; Hermes, Robert E; Moore, Andrew M T; Kennett, Douglas J; Weaver, James C; Wittke, James H; DeCarli, Paul S; Bischoff, James L; Hillman, Gordon C; Howard, George A; Kimbel, David R; Kletetschka, Gunther; Lipo, Carl P; Sakai, Sachiko; Revay, Zsolt; West, Allen; Firestone, Richard B; Kennett, James P

    2012-07-10

    It has been proposed that fragments of an asteroid or comet impacted Earth, deposited silica- and iron-rich microspherules and other proxies across several continents, and triggered the Younger Dryas cooling episode 12,900 years ago. Although many independent groups have confirmed the impact evidence, the hypothesis remains controversial because some groups have failed to do so. We examined sediment sequences from 18 dated Younger Dryas boundary (YDB) sites across three continents (North America, Europe, and Asia), spanning 12,000 km around nearly one-third of the planet. All sites display abundant microspherules in the YDB with none or few above and below. In addition, three sites (Abu Hureyra, Syria; Melrose, Pennsylvania; and Blackville, South Carolina) display vesicular, high-temperature, siliceous scoria-like objects, or SLOs, that match the spherules geochemically. We compared YDB objects with melt products from a known cosmic impact (Meteor Crater, Arizona) and from the 1945 Trinity nuclear airburst in Socorro, New Mexico, and found that all of these high-energy events produced material that is geochemically and morphologically comparable, including: (i) high-temperature, rapidly quenched microspherules and SLOs; (ii) corundum, mullite, and suessite (Fe(3)Si), a rare meteoritic mineral that forms under high temperatures; (iii) melted SiO(2) glass, or lechatelierite, with flow textures (or schlieren) that form at > 2,200 °C; and (iv) particles with features indicative of high-energy interparticle collisions. These results are inconsistent with anthropogenic, volcanic, authigenic, and cosmic materials, yet consistent with cosmic ejecta, supporting the hypothesis of extraterrestrial airbursts/impacts 12,900 years ago. The wide geographic distribution of SLOs is consistent with multiple impactors.

  19. Clusters and the Cosmic Web

    CERN Document Server

    Van de Weygaert, R

    2006-01-01

    We discuss the intimate relationship between the filamentary features and the rare dense compact cluster nodes in this network, via the large scale tidal field going along with them, following the cosmic web theory developed Bond et al. The Megaparsec scale tidal shear pattern is responsible for the contraction of matter into filaments, and its link with the cluster locations can be understood through the implied quadrupolar mass distribution in which the clusters are to be found at the sites of the overdense patches. We present a new technique for tracing the cosmic web, identifying planar walls, elongated filaments and cluster nodes in the galaxy distribution. This will allow the practical exploitation of the concept of the cosmic web towards identifying and tracing the locations of the gaseous WHIM. These methods, the Delaunay Tessellation Field Estimator (DTFE) and the Morphology Multiscale Filter (MMF) find their basis in computational geometry and visualization.

  20. Cosmic rays and particle physics

    CERN Document Server

    Gaisser, Thomas K; Resconi, Elisa

    2016-01-01

    Fully updated for the second edition, this book introduces the growing and dynamic field of particle astrophysics. It provides an overview of high-energy nuclei, photons and neutrinos, including their origins, their propagation in the cosmos, their detection on Earth and their relation to each other. Coverage is expanded to include new content on high energy physics, the propagation of protons and nuclei in cosmic background radiation, neutrino astronomy, high-energy and ultra-high-energy cosmic rays, sources and acceleration mechanisms, and atmospheric muons and neutrinos. Readers are able to master the fundamentals of particle astrophysics within the context of the most recent developments in the field. This book will benefit graduate students and established researchers alike, equipping them with the knowledge and tools needed to design and interpret their own experiments and, ultimately, to address a number of questions concerning the nature and origins of cosmic particles that have arisen in recent resea...

  1. Cosmic Ray Origins: An Introduction

    Science.gov (United States)

    Blandford, Roger; Simeon, Paul; Yuan, Yajie

    2014-11-01

    Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

  2. Cosmic Ray Origins: An Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Blandford, Roger; Simeon, Paul; Yuan, Yajie

    2014-11-15

    Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

  3. Cosmic Ray Origins: An Introduction

    CERN Document Server

    Blandford, Roger; Yuan, Yajie

    2014-01-01

    Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

  4. Cosmic Ray Energetics and Mass

    CERN Document Server

    Baylon cardiel, J L; Wallace, K C; Anderson, T B; Copley, M

    The cosmic-ray energetics and mass (CREAM) investigation is designed to measure cosmic-ray composition to the supernova energy scale of 10$^{15}$ eV in a series of ultra long duration balloon (ULDB) flights. The first flight is planned to be launched from Antarctica in December 2004. The goal is to observe cosmic-ray spectral features and/or abundance changes that might signify a limit to supernova acceleration. The particle ($\\{Z}$) measurements will be made with a timing-based charge detector and a pixelated silicon charge detector to minimize the effect of backscatter from the calorimeter. The particle energy measurements will be made with a transition radiation detector (TRD) for $\\{Z}$ > 3 and a sampling tungsten/scintillator calorimeter for $\\{Z}$ $\\geq$1 particles, allowing inflight cross calibration of the two detectors. The status of the payload construction and flight preparation are reported in this paper.

  5. Cosmic Rays: What Gamma Rays Can Say

    OpenAIRE

    2014-01-01

    We will review the main channels of gamma ray emission due to the acceleration and propagation of cosmic rays, discussing the cases of both galactic and extra-galactic cosmic rays and their connection with gamma rays observations.

  6. The Cosmic Shoreline

    Science.gov (United States)

    Zahnle, Kevin J.; Catling, D. C.

    2013-01-01

    in 2004 when there were just two transiting exoplanets to consider. The trend was well-defined by late 2007. Figure 1 shows how matters stood in Dec 2012 with approx.240 exoplanets. The figure shows that the boundary between planets with and without active volatiles - the cosmic shoreline, as it were - is both well-defined and follows a power law.

  7. Cosmic Humanity: Utopia, Realities, Prospects

    Directory of Open Access Journals (Sweden)

    Sergey Krichevsky

    2017-07-01

    Full Text Available The philosophical foundations of the theory and practice of the creation of cosmic humanity as a process of the evolution of human civilization, the emergence into space, with the prospect of resettlement outside the Earth are considered. There is a connection between myths, fantasies, ideas, concepts and projects aimed at the exploration of outer space, the creation of cosmic humanity. A new and voluminous definition of cosmic humanity in the evolutionary paradigm is given. Cosmic humanity is (essence and 4 stages of evolution: 1. Humanity living on Earth, sensing, knowing, understanding its cosmic origin, relationship with the cosmos and cosmic destiny. 2. Humanity living on Earth, leading aerospace activity for the purposes of exploration and use of aerospace space (Heaven, Space for survival and development. 3. Humanity living on Earth and outside the Earth — in the solar system, preserving the Earth and mastering the Cosmos for survival and development. 4. Humanity, settled and living in the Cosmos. Now humanity is in the process of transition from the second to the third stage. In the process of this evolution, a complex transformation of man and society takes place. The problem-semantic field of cosmic humanity is described and its general model is presented. The meta-goal-setting is the justification of cosmic humanity with the application of the anthropic principle and its “active” super (post anthropic supplement: “Cosmic humanity has an evolutionary purpose to actively manage evolution: change man, humanity and the universe.” The evolution of the “cosmic dream”, goals and technologies of space activities is formalized in the form of a conceptual model. Challenges and negative trends are considered in connection with the crisis of space activity, criticism and attempts to limit the flights of people into space. The prototype of cosmic humanity, its basis and acting model is the cosmonauts’ community. The main

  8. Origin of cosmic magnetic fields

    Science.gov (United States)

    Rees, M. J.

    2006-06-01

    The first significant cosmic fields, and the seed field for galactic dynamos probably developed after the formation of the first non-linear structures. The history of star formation and the intergalactic medium is controlled, at least in part, by how and when galaxies and their precursors acquired their fields. The amplification of fields behind shocks, and the diffusivity of the magnetic flux, are crucial to the interpretation of radio sources, gamma ray burst afterglows, and other energetic cosmic phenomena. The build-up of magnetic fields is an important aspect of the overall cosmogonic process.

  9. Neutralino Clumps and Cosmic Rays

    CERN Document Server

    Salati, P

    2007-01-01

    The halo of the Miky Way might contain numerous and dense substructures inside which the putative weakly interacting massive particles (suggested as the main constituent of the astronomical dark matter) would produce a stronger annihilation signal than in the smooth regions. The closer the nearest clump, the larger the positron and antiproton cosmic ray fluxes at the Earth. But the actual distribution of these substructures is not known. The predictions on the antimatter yields at the Earth are therefore affected by a kind of cosmic variance whose analysis is the subject of this contribution. The statistical tools to achieve that goal are presented and Monte Carlo simulations are compared to analytic results.

  10. Cosmic Strings with Small Tension

    CERN Document Server

    Halyo, Edi

    2009-01-01

    We describe cosmic F--term strings with exponentially small tension which are D3 branes wrapped on deformed $A_3$ singularities. We show that brane instanton effects which can be calculated after a geometric transition give rise to an exponentially small volume for the node on which the D3 branes wrap leading to a string with small tension. We generalize our description to the case of non--Abelian cosmic strings and argue that these strings are stable against monopole--anti monopole pair creation.

  11. Aligned interactions in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Kempa, J., E-mail: kempa@pw.plock.pl [Warsaw University of Technology Branch Plock (Poland)

    2015-12-15

    The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.

  12. Closing CMS to hunt cosmic rays

    CERN Multimedia

    Claudia Marcelloni

    2006-01-01

    Every second the Earth is bombarded by billions of cosmic rays and occasionally one of these cosmic particles will collide with the Earth's atmosphere generating a shower of particles known as an 'air shower'. This is similiar to the collisions and subsequent particle showers observed in accelerators such as the LHC. Here the CMS detector is closed so that systems can be tested using muon cosmic rays in the 'Cosmic Challenge'.

  13. Cosmic-Ray Detectors With Interdigitated Electrodes

    Science.gov (United States)

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

    1995-01-01

    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.

  14. Voids and the Cosmic Web: cosmic depression & spatial complexity

    NARCIS (Netherlands)

    van de Weygaert, Rien; Shandarin, S.; Saar, E.; Einasto, J.

    2016-01-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do theyrepresent a key constituent of the Cosmic Web, they also are one of the cleanest probesand measures of global cosmological parameters. The shape and evolution of voids are highly sensitive tothe natu

  15. Cosmic radiation exposure at aircraft crew workplaces

    Energy Technology Data Exchange (ETDEWEB)

    Latocha, M.; Beck, P.; Rollet, S. [ARC Seibersdorf Research, Seibersdorf (Austria); Latocha, M. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland)

    2006-07-01

    E.U.R.A.D.O.S. working group W.G.5. on air crew dosimetry coordinated research of some 24 international institutes to exchange experimental data and results of calculations of the radiation exposure in aircraft altitudes due to cosmic radiation. The purpose was to provide a data-set for all European Union Member States for the assessment of individual doses, the validity of different approaches, and to provide an input to technical recommendations by the Article 31 group of experts and the European Commission. The results of this work have been recently published and are available for the international community. The radiation protection quantity of interest is effective dose, E (ISO), but the comparison of measurement results and the results of calculations, is done in terms of the operational quantity ambient dose equivalent, H{sup *}(10). This paper gives an overview of the E.U.R.A.D.O.S. Aircraft Crew In-Flight Database which was implemented under the responsibility of A.R.C. Seibersdorf research. It discusses calculation models for air crew dose assessment comparing them with measurements contained in this database. Further it presents current developments using updated information of galactic cosmic radiation proton spectra and new results of the recently finalized European research project D.O.S.M.A.X. on dosimetry of aircraft crew at solar maximum. (authors)

  16. Origin and propagation of galactic cosmic rays

    Science.gov (United States)

    Cesarsky, Catherine J.; Ormes, Jonathan F.

    1987-01-01

    The study of systematic trends in elemental abundances is important for unfolding the nuclear and/or atomic effects that should govern the shaping of source abundances and in constraining the parameters of cosmic ray acceleration models. In principle, much can be learned about the large-scale distributions of cosmic rays in the galaxy from all-sky gamma ray surveys such as COS-B and SAS-2. Because of the uncertainties in the matter distribution which come from the inability to measure the abundance of molecular hydrogen, the results are somewhat controversial. The leaky-box model accounts for a surprising amount of the data on heavy nuclei. However, a growing body of data indicates that the simple picture may have to be abandoned in favor of more complex models which contain additional parameters. Future experiments on the Spacelab and space station will hopefully be made of the spectra of individual nuclei at high energy. Antiprotons must be studied in the background free environment above the atmosphere with much higher reliability and presion to obtain spectral information.

  17. Chandra Discovers Cosmic Cannonball

    Science.gov (United States)

    2007-11-01

    One of the fastest moving stars ever seen has been discovered with NASA's Chandra X-ray Observatory. This cosmic cannonball is challenging theories to explain its blistering speed. Astronomers used Chandra to observe a neutron star, known as RX J0822-4300, over a period of about five years. During that span, three Chandra observations clearly show the neutron star moving away from the center of the Puppis A supernova remnant. This remnant is the stellar debris field created during the same explosion in which the neutron star was created about 3700 years ago. Chandra X-ray Image of RX J0822-4300 in Puppis A Chandra X-ray Image of RX J0822-4300 in Puppis A By combining how far it has moved across the sky with its distance from Earth, astronomers determined the neutron star is moving at over 3 million miles per hour. At this rate, RX J0822-4300 is destined to escape from the Milky Way after millions of years, even though it has only traveled about 20 light years so far. "This star is moving at 3 million miles an hour, but it's so far away that the apparent motion we see in five years is less than the height of the numerals in the date on a penny, seen from the length of a football field," said Frank Winkler of Middlebury College in Vermont. "It's remarkable, and a real testament to the power of Chandra, that such a tiny motion can be measured." Labeled Image of RX J0822-4300 in Puppis A Labeled Image of RX J0822-4300 in Puppis A "Just after it was born, this neutron star got a one-way ticket out of the Galaxy," said co-author Robert Petre of NASA's Goddard Space Flight Center in Greenbelt, Md. "Astronomers have seen other stars being flung out of the Milky Way, but few as fast as this." So-called hypervelocity stars have been previously discovered shooting out of the Milky Way with speeds around one million miles per hour. One key difference between RX J0822-4300 and these other reported galactic escapees is the source of their speed. The hypervelocity stars are

  18. Cosmic Ray elimination using the Wavelet Transform

    Science.gov (United States)

    Orozco-Aguilera, M. T.; Cruz, J.; Altamirano, L.; Serrano, A.

    2009-11-01

    In this work, we present a method for the automatic cosmic ray elimination in a single CCD exposure using the Wavelet Transform. The proposed method can eliminate cosmic rays of any shape or size. With this method we can eliminate over 95% of cosmic rays in a spectral image.

  19. COSMIC RAY ELIMINATION USING THE WAVELET TRANSFORM

    Directory of Open Access Journals (Sweden)

    M. T. Orozco-Aguilera

    2009-01-01

    Full Text Available In this work, we present a method for the automatic cosmic ray elimination in a single CCD exposure using the Wavelet Transform. The proposed method can eliminate cosmic rays of any shape or size. With this method we can eliminate over 95% of cosmic rays in a spectral image.

  20. The Cosmic Ray Electron Excess

    Science.gov (United States)

    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

    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.

  1. Evolution of the cosmic web

    NARCIS (Netherlands)

    Cautun, Marius; van de Weygaert, Rien; Jones, Bernard J. T.; Frenk, Carlos S.

    2014-01-01

    The cosmic web is the largest scale manifestation of the anisotropic gravitational collapse of matter. It represents the transitional stage between linear and non-linear structures and contains easily accessible information about the early phases of structure formation processes. Here we investigate

  2. Cosmic Censorship for Gowdy Spacetimes.

    Science.gov (United States)

    Ringström, Hans

    2010-01-01

    Due to the complexity of Einstein's equations, it is often natural to study a question of interest in the framework of a restricted class of solutions. One way to impose a restriction is to consider solutions satisfying a given symmetry condition. There are many possible choices, but the present article is concerned with one particular choice, which we shall refer to as Gowdy symmetry. We begin by explaining the origin and meaning of this symmetry type, which has been used as a simplifying assumption in various contexts, some of which we shall mention. Nevertheless, the subject of interest here is strong cosmic censorship. Consequently, after having described what the Gowdy class of spacetimes is, we describe, as seen from the perspective of a mathematician, what is meant by strong cosmic censorship. The existing results on cosmic censorship are based on a detailed analysis of the asymptotic behavior of solutions. This analysis is in part motivated by conjectures, such as the BKL conjecture, which we shall therefore briefly describe. However, the emphasis of the article is on the mathematical analysis of the asymptotics, due to its central importance in the proof and in the hope that it might be of relevance more generally. The article ends with a description of the results that have been obtained concerning strong cosmic censorship in the class of Gowdy spacetimes.

  3. Global diffusion of cosmic rays

    CERN Document Server

    Snodin, A P; Sarson, G R; Bushby, P J; Rodrigues, L F S

    2015-01-01

    The propagation of charged particles, including cosmic rays, in a partially ordered magnetic field is characterized by a diffusion tensor whose components depend on the particle's Larmor radius $R_L$ and the degree of order in the magnetic field. This prescription relies explicitly on the assumption of a scale separation between random and mean magnetic fields, which usually applies in laboratory plasmas, but not in most astrophysical environments such as the interstellar medium (ISM). Direct estimates of the cosmic-ray diffusion tensor from test particle simulations have explored the range of particle energies corresponding to $10^{-2} \\lesssim R_L/l_c \\lesssim 10^{3}$, where $l_c$ is the magnetic correlation length. Modern simulations of the ISM have numerical resolution of order 1 pc, so the Larmor radius of the cosmic ray particles that dominate in their energy density is at least $10^{6}$ times smaller than the numerically resolved scales of the random magnetic field. Large-scale simulations of cosmic ra...

  4. Cosmic Logic: a Computational Model

    CERN Document Server

    Vanchurin, Vitaly

    2015-01-01

    We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or G{\\" o}del number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies...

  5. Decoherence, Entanglement and Cosmic Evolution

    CERN Document Server

    Capozziello, Salvatore

    2013-01-01

    The possible imprint of quantum decoherence, in the framework of cosmology, is here investigated. Particular attention is paid to the observational fact that entanglement could lead to the interaction of different eras of cosmic evolution. The role played by decoherence provides the existence of "quantum entanglement" between cosmological eras giving, as observational results, dynamical constraints on the corresponding cosmological models.

  6. Cosmic Rays and Radiative Instabilities

    CERN Document Server

    Hartquist, T W; Falle, S A E G; Pittard, J M; Van Loo, S

    2011-01-01

    In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance of the thermal instablity for the formation of clouds in the interstellar medium. Even in the past several years, many papers have concerned the role of the thermal instability in the production of molecular clouds. About three and a half decades ago, astrophysicists investigating radiative shocks noticed that for many cooling laws such shocks are unstable. Attempts to address the effects of cosmic rays on the stablity of radiative media that are initially uniform or that have just passed through shocks have been made. The simplest approach to such studies involves the assumption that the cosmic rays behave as a fluid. Work based on such an approach is described. Cosmic rays have no effect on the stability of initially uniform, static media with respect to isobaric perturb...

  7. The L3+Cosmics experiment

    CERN Document Server

    Le Coultre, Pierre

    2003-01-01

    Thanks to the unique properties of the L3+C detector, muon research topics relevant to various current problems in cosmic ray and particle astrophysics can be studied. A short overview of the physics topics is presented as well as a description of the detector. (19 refs).

  8. Cosmology, Relativity and Cosmic Rays

    Science.gov (United States)

    López, Rebeca; Martínez, Humberto; Zepeda, Arnulfo

    2009-04-01

    This is a short review of the evolution of ideas and concepts about the Universe. It is based on the introductory talk given on the 25 of July 2008 within the Third School on Cosmic Rays and Astrophysics held in Arequipa, Peru.

  9. Fireballs from Superconducting Cosmic Strings

    CERN Document Server

    Gruzinov, Andrei

    2016-01-01

    Thermalized fireballs should be created by cusp events on superconducting cosmic strings. This simple notion allows to reliably estimate particle emission from the cusps in a given background magnetic field. With plausible assumptions about intergalactic magnetic fields, the cusp events can produce observable fluxes of high-energy photons and neutrinos with unique signatures.

  10. Fireballs from superconducting cosmic strings

    Science.gov (United States)

    Gruzinov, Andrei; Vilenkin, Alexander

    2017-01-01

    Thermalized fireballs should be created by cusp events on superconducting cosmic strings. This simple notion allows to reliably estimate particle emission from the cusps in a given background magnetic field. With plausible assumptions about intergalactic magnetic fields, the cusp events can produce observable fluxes of high-energy photons and neutrinos with unique signatures.

  11. Surprising results from cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Wilk, G. [Soltan Institute for Nuclear Studies, Warsaw (Poland); Wlodarczyk, Z. [Institute for Physics, Pedagogical University, Kielce (Poland)

    1996-10-01

    A number of seemingly exotic phenomena seen in the highest cosmic-ray experiments are briefly discussed. We argue that they indicate existence of non-statistical fluctuations and strong correlations in the fragmentation region of multiparticle production processes unaccessible to the present accelerators. (author) 12 refs, 3 figs

  12. Individualizing Services, Individualizing Responsibility

    DEFF Research Database (Denmark)

    Garsten, Christina; Hollertz, Katarina; Jacobsson, Kerstin

    and responsibilising the unemployed individual? The paper finds that the individualisation that is taking place occurs as an individualisation of responsibility, more than as an individualisation of interventions. A related finding is that the social rights perspective is becoming performance......-oriented, and the normative demands placed on individuals appear increasingly totalizing, concerning the whole individual rather than the job-related aspects only. The paper is based on 23 in-depth interviews with individual clients as well as individual caseworkers and other professionals engaged in client-related work...

  13. Galactic cosmic ray propagation models using Picard

    CERN Document Server

    Kissmann, Ralf; Strong, Andrew W

    2015-01-01

    We present results obtained from our newly developed Galactic cosmic-ray transport code PICARD, that solves the cosmic-ray transport equation. This code allows for the computation of cosmic-ray spectra and the resulting gamma-ray emission. Relying on contemporary numerical solvers allows for efficient computation of models with deca-parsec resolution. PICARD can handle locally anisotropic spatial diffusion acknowledging a full diffusion tensor. We used this framework to investigate the transition from axisymmetric to spiral-arm cosmic-ray source distributions. Wherever possible we compare model predictions with constraining observables in cosmic-ray astrophysics.

  14. Cosmic rays and hadronic interactions

    Directory of Open Access Journals (Sweden)

    Lipari Paolo

    2015-01-01

    Full Text Available The study of cosmic rays, and more in general of the “high energy universe” is at the moment a vibrant field that, thanks to the observations by several innovative detectors for relativistic charged particles, gamma–rays, and neutrinos continue to generate surprising and exciting results. The progress in the field is rapid but many fundamental problems remain open. There is an intimate relation between the study of the high energy universe and the study of the properties of hadronic interactions. High energy cosmic rays can only be studied detecting the showers they generate in the atmosphere, and for the interpretation of the data one needs an accurate modeling of the collisions between hadrons. Also the study of cosmic rays inside their sources and in the Galaxy requires a precise description of hadronic interactions. A program of experimental studies at the LHC and at lower energy, designed to address the most pressing problems, could significantly reduce the existing uncertainties and is very desirable. Such an experimental program would also have a strong intrinsic scientific interest, allowing the broadening and deepening of our understanding of Quantum Chromo Dynamics in the non–perturbative regime, the least understood sector of the Standard Model of particle physics. It should also be noted that the cosmic ray spectrum extends to particles with energy E ∼ 1020 eV, or a nucleon–nucleon c.m. energy √s ≃ 430 TeV, 30 times higher than the current LHC energy. Cosmic ray experiments therefore offer the possibility to perform studies on the properties of hadronic interactions that are impossible at accelerators.

  15. Book review: Land of the cosmic race: race mixture, racism and blackness in Mexico

    OpenAIRE

    Feghali, Zalfa

    2013-01-01

    "Land of the Cosmic Race: Race Mixture, Racism, and Blackness in Mexico." Christina A. Sue. Oxford University Press. March 2013. --- Land of the Cosmic Race is a richly-detailed ethnographic account of the powerful role that race and colour play in organizing the lives and thoughts of ordinary Mexicans. It presents a previously untold story of how individuals in contemporary urban Mexico construct their identities, attitudes, and practices in the context of a dominant national belief system. ...

  16. Measurements of cosmic-ray energy spectra with the 2nd CREAM flight

    CERN Document Server

    Maestro, P; Allison, P; Bagliesi, M G; Barbier, L; Beatty, J J; Bigongiari, G; Brandt, T J; Childers, J T; Conklin, N B; Coutu, S; DuVernois, M A; Ganel, O; Han, J H; Jeon, J A; Kim, K C; Lee, M H; Malinine, A; Marrocchesi, P S; Minnick, S; Mognet, S I; Nam, S W; Nutter, S; Park, I H; Park, N H; Seo, E S; Sina, R; Walpole, P; Wu, J; Yang, J; Yoon, Y S; Zei, R; Zinn, S Y; 10.1016/j.nuclphysbps.2009.09.045

    2010-01-01

    During its second Antarctic flight, the CREAM (Cosmic Ray Energetics And Mass) balloon experiment collected data for 28 days, measuring the charge and the energy of cosmic rays (CR) with a redundant system of particle identification and an imaging thin ionization calorimeter. Preliminary direct measurements of the absolute intensities of individual CR nuclei are reported in the elemental range from carbon to iron at very high energy.

  17. Cosmic ray decreases and magnetic clouds

    Energy Technology Data Exchange (ETDEWEB)

    Cane, H.V. (NASA Goddard Space Flight Center, Greenbelt, MD (United States))

    1993-03-01

    A study has been made of energetic particle data, obtained from IMP 8, in conjunction with solar wind field and plasma data at the times of reported magnetic clouds. It is shown that magnetic clouds can cause a depression of the cosmic ray flux but high fields are required. A depression of 3% in a neutron monitor requires a field of about 25 nT. Such high fields are found only in a subset of coronal ejecta. The principal cause for Forbush decreases associated with energetic shocks is probably turbulence in the postshock region, although some shocks will be followed by an ejecta with a high field. Each event is different. The lower-energy particles can help in identifying the dominant processes in individual events. 19 refs., 5 figs.

  18. Composition of Primary Cosmic-Ray Nuclei at High Energies

    CERN Document Server

    Ave, M; Gahbauer, F; Hoppner, C; Hörandel, J R; Ichimura, M; Müller, D; Romero-Wolf, A

    2008-01-01

    The TRACER instrument (``Transition Radiation Array for Cosmic Energetic Radiation'') has been developed for direct measurements of the heavier primary cosmic-ray nuclei at high energies. The instrument had a successful long-duration balloon flight in Antarctica in 2003. The detector system and measurement process are described, details of the data analysis are discussed, and the individual energy spectra of the elements O, Ne, Mg, Si, S, Ar, Ca, and Fe (nuclear charge Z=8 to 26) are presented. The large geometric factor of TRACER and the use of a transition radiation detector make it possible to determine the spectra up to energies in excess of 10$^{14}$ eV per particle. A power-law fit to the individual energy spectra above 20 GeV per amu exhibits nearly the same spectral index ($\\sim$ 2.65 $\\pm$ 0.05) for all elements, without noticeable dependence on the elemental charge Z.

  19. Cosmic vacuum energy decay and creation of cosmic matter

    CERN Document Server

    Fahr, H J

    2016-01-01

    In the more recent literature on cosmological evolutions of the universe the cosmic vacuum energy has become a non-renouncable ingredient. The cosmological constant $\\Lambda$, first invented by Einstein, but later also rejected by him, presently experiences an astonishing revival. Interestingly enough it acts, like a constant vacuum energy density would also do. Namely, it has an accelerating action on cosmic dynamics without which, as it appears, presently obtained cosmological data cannot be conciliated with theory. As we are going to show in this review, however, the concept of a constant vacuum energy density is unsatisfactory for very basic reasons, since it would claim for a physical reality that acts upon spacetime and matter dynamics without itself being acted upon by spacetime or matter.

  20. Voids and the Cosmic Web: cosmic depressions & spatial complexity

    CERN Document Server

    van de Weygaert, Rien

    2016-01-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do they represent a key constituent of the Cosmic Web, they also are one of the cleanest probes and measures of global cosmological parameters. The shape and evolution of voids are highly sensitive to the nature of dark energy, while their substructure and galaxy population provides a direct key to the nature of dark matter. Also, the pristine environment of void interiors is an important testing ground for our understanding of environmental influences on galaxy formation and evolution. In this paper, we review the key aspects of the structure and dynamics of voids, with a particular focus on the hierarchical evolution of the void population. We demonstrate how the rich structural pattern of the Cosmic Web is related to the complex evolution and buildup of voids.

  1. Dynamic Cosmic Strings Numerical evolution of excited Cosmic Strings

    CERN Document Server

    Sperhake, U; Vickers, J A

    2001-01-01

    An implicit, fully characteristic, numerical scheme for solving the field equations of a cosmic string coupled to gravity is described. The inclusion of null infinity as part of the numerical grid allows us to apply suitable boundary conditions on the metric and matter fields to suppress unphysical divergent solutions. The code is tested by comparing the results with exact solutions, checking that static cosmic string initial data remain constant when evolved and undertaking a time dependent convergence analysis of the code. It is shown that the code is accurate, stable and exhibits clear second order convergence. The code is used to analyse the interaction between a Weber--Wheeler pulse of gravitational radiation with the string. The interaction causes the string to oscillate at frequencies inversely proportional to the masses of the scalar and vector fields of the string. After the pulse has largely radiated away the string continues to ring but the oscillations slowly decay and eventually the variables ret...

  2. Voids and the Cosmic Web: cosmic depression & spatial complexity

    Science.gov (United States)

    van de Weygaert, Rien

    2016-10-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do theyrepresent a key constituent of the Cosmic Web, they also are one of the cleanest probesand measures of global cosmological parameters. The shape and evolution of voids are highly sensitive tothe nature of dark energy, while their substructure and galaxy population provides a direct key to thenature of dark matter. Also, the pristine environment of void interiors is an important testing groundfor our understanding of environmental influences on galaxy formation and evolution. In this paper, we reviewthe key aspects of the structure and dynamics ofvoids, with a particular focus on the hierarchical evolution of the void population. We demonstratehow the rich structural pattern of the Cosmic Web is related to the complex evolution and buildupof voids.

  3. Evolution of the cosmic web

    CERN Document Server

    Cautun, Marius; Jones, Bernard J T; Frenk, Carlos S

    2014-01-01

    The cosmic web is the largest scale manifestation of the anisotropic gravitational collapse of matter. It represents the transitional stage between linear and non-linear structures and contains easily accessible information about the early phases of structure formation processes. Here we investigate the characteristics and the time evolution of morphological components since. Our analysis involves the application of the NEXUS Multiscale Morphology Filter (MMF) technique, predominantly its NEXUS+ version, to high resolution and large volume cosmological simulations. We quantify the cosmic web components in terms of their mass and volume content, their density distribution and halo populations. We employ new analysis techniques to determine the spatial extent of filaments and sheets, like their total length and local width. This analysis identifies cluster and filaments as the most prominent components of the web. In contrast, while voids and sheets take most of the volume, they correspond to underdense environ...

  4. Nexus of the Cosmic Web

    CERN Document Server

    Cautun, Marius; Jones, Bernard J T; Frenk, Carlos S; Hellwing, Wojcieh A

    2012-01-01

    One of the important unknowns of current cosmology concerns the effects of the large scale distribution of matter on the formation and evolution of dark matter haloes and galaxies. One main difficulty in answering this question lies in the absence of a robust and natural way of identifying the large scale environments and their characteristics. This work summarizes the NEXUS+ formalism which extends and improves our multiscale scale-space MMF method. The new algorithm is very successful in tracing the Cosmic Web components, mainly due to its novel filtering of the density in logarithmic space. The method, due to its multiscale and hierarchical character, has the advantage of detecting all the cosmic structures, either prominent or tenuous, without preference for a certain size or shape. The resulting filamentary and wall networks can easily be characterized by their direction, thickness, mass density and density profile. These additional environmental properties allows to us to investigate not only the effect...

  5. Aerosols Produced by Cosmic Rays

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker

    , it will be possible to develop the experiment to cover additional processes involved in the route to cloud droplet formation. The experiment will be conducted at the Danish National Space Center where a clean room facility has been provided. It comprises a 7 m3 reaction chamber across which an electric field......Satellite observations have shown that the Earth’s cloud cover is strongly correlated with the galactic cosmic ray flux. While this correlation is indicative of a possible physical connection, there is currently no confirmation that a physical mechanism exists. We are therefore setting up...... mechanism linking cosmic rays to clouds and climate is currently speculative, there have been various suggestions of the role atmospheric ions may play; these involve any one of a number of processes from the nucleation of aerosols up to the collection processes of cloud droplets. We have chosen to start...

  6. The Imperatives of Cosmic Biology

    CERN Document Server

    Gibson, Carl H

    2010-01-01

    The transformation of organic molecules into the simplest self-replicating living system,a microorganism, is accomplished from a unique event or rare events that occurred early in the Universe. The subsequent dispersal on cosmic scales and evolution of life is guaranteed, being determined by well-understood processes of physics and biology. Entire galaxies and clusters of galaxies can be considered as connected biospheres, with lateral gene transfers, as initially theorized by Joseph (2000), providing for genetic mixing and Darwinian evolution on a cosmic scale. Big bang cosmology modified by modern fluid mechanics suggests the beginning and wide intergalactic dispersal of life occurred immediately after the end of the plasma epoch when the gas of protogalaxies in clusters fragmented into clumps of planets. Stars are born from binary mergers of such planets within such clumps. When stars devour their surrounding planets to excess they explode, distributing necessary fertilizing chemicals created only in stars...

  7. Cosmic Strings on the Lattice

    CERN Document Server

    Bukenov, A K; Polikarpov, M I; Polley, L; Wiese, U J

    1992-01-01

    We develop a formalism for the quantization of topologically stable excitations in the 4-dimensional abelian lattice gauge theory. The excitations are global and local (Abrikosov-Nielsen-Olesen) strings and monopoles. The operators of creation and annihilation of string states are constructed; the string Green functions are represented as a path integral over random surfaces. Topological excitations play an important role in the early universe. In the broken symmetry phase of the $U(1)$ spin model, closed global cosmic strings arise, while in the Higgs phase of the noncompact gauge-Higgs model, local cosmic strings are present. The compact gauge-Higgs model also involves monopoles. Then the strings can break if their ends are capped by monopoles. The topology of the Euclidean string world sheets are studied by numerical simulations.

  8. Cosmic Revelation: Making Astroparticles Visible

    Science.gov (United States)

    Roth, T. O.; Haungs, A.; Schieler, H.; Weindl, A.

    2010-06-01

    Cosmic Revelation is a prime example of a successful art and science project connecting art and astroparticle physics. One of the main reasons for its success might be that the collaboration between the KArlsruhe Shower Core and Array DEtector (KASCADE) experiment and Tim Otto Roth is both a minimalist light art project and a scientific experiment. In a field of 16 flashing mirror sculptures connected to the KASCADE detector field at KIT (Karlsruhe Institute of Technology, Germany) the impact of high energy cosmic rays on Earth can be experienced directly. In just one year the project has developed from the initial concept to its first presentation in a public space in autumn 2008. We explain how the project developed, and also highlight the practical and conceptual conditions for its realisation.

  9. Emergent Spacetime and Cosmic Inflation

    CERN Document Server

    Yang, Hyun Seok

    2015-01-01

    We propose a background-independent formulation of cosmic inflation. The inflation in this picture corresponds to a dynamical process to generate space and time while the conventional inflation is simply an (exponential) expansion of a preexisting spacetime owing to the vacuum energy carried by an inflaton field. We observe that the cosmic inflation is triggered by the condensate of Planck energy into vacuum responsible for the generation of spacetime and must be a single event according to the exclusion principle of noncommutative spacetime caused by the Planck energy condensate in vacuum. The emergent spacetime picture admits a background-independent formulation so that the inflation can be described by a conformal Hamiltonian system characterized by an exponential phase space expansion without introducing any inflaton field as well as an ad hoc inflation potential. This implies that the emergent spacetime may incapacitate all the rationales to introduce the multiverse hypothesis.

  10. Cosmic Visions Dark Energy: Technology

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Heitmann, Katrin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Hirata, Chris [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Roodman, Aaron [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Seljak, Uroš [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Slosar, Anže [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Trodden, Mark [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-04-26

    A strong instrumentation and detector R&D program has enabled the current generation of cosmic frontier surveys. A small investment in R&D will continue to pay dividends and enable new probes to investigate the accelerated expansion of the universe. Instrumentation and detector R&D provide critical training opportunities for future generations of experimentalists, skills that are important across the entire Department of Energy High Energy Physics program.

  11. Electromagnetic field and cosmic censorship

    CERN Document Server

    Düztaş, Koray

    2013-01-01

    We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.

  12. Cosmic crystallography in a circle

    CERN Document Server

    Teixeira, A F F

    2000-01-01

    In a circle (an $S^1$) with circumference 1 assume $m$ objects distributed pseudo-randomly. In the universal covering $R^1$ assume the objects replicated accordingly, and take an interval $L>1$. In this interval, make the normalized histogram of the pair separations which are not an integer. The theoretical (expected) such histogram is obtained in this report, as well as its difference to a similar histogram for non-replicated objects. The whole study is of interest for the cosmic crystallography.

  13. Racetrack Inflation and Cosmic Strings

    CERN Document Server

    Brax, Philippe; Davis, Anne-Christine; Davis, Stephen C; Jeannerot, Rachel; Postma, Marieke

    2008-01-01

    We consider the coupling of racetrack inflation to matter fields as realised in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that string formation before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation.

  14. Charged Cosmic Rays and Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kachelrieß, M.

    2013-04-15

    High-energy neutrino astronomy has grown up, with IceCube as one of its main experiments having sufficient sensitivity to test “vanilla” models of astrophysical neutrinos. I review predictions of neutrino fluxes as well as the status of cosmic ray physics. I comment also briefly on an improvement of the Fermi-LAT limit for cosmogenic neutrinos and on the two neutrino events presented by IceCube first at “Neutrino 2012”.

  15. Cosmic microwave background theory

    Science.gov (United States)

    Bond, J. Richard

    1998-01-01

    A long-standing goal of theorists has been to constrain cosmological parameters that define the structure formation theory from cosmic microwave background (CMB) anisotropy experiments and large-scale structure (LSS) observations. The status and future promise of this enterprise is described. Current band-powers in ℓ-space are consistent with a ΔT flat in frequency and broadly follow inflation-based expectations. That the levels are ∼(10−5)2 provides strong support for the gravitational instability theory, while the Far Infrared Absolute Spectrophotometer (FIRAS) constraints on energy injection rule out cosmic explosions as a dominant source of LSS. Band-powers at ℓ ≳ 100 suggest that the universe could not have re-ionized too early. To get the LSS of Cosmic Background Explorer (COBE)-normalized fluctuations right provides encouraging support that the initial fluctuation spectrum was not far off the scale invariant form that inflation models prefer: e.g., for tilted Λ cold dark matter sequences of fixed 13-Gyr age (with the Hubble constant H0 marginalized), ns = 1.17 ± 0.3 for Differential Microwave Radiometer (DMR) only; 1.15 ± 0.08 for DMR plus the SK95 experiment; 1.00 ± 0.04 for DMR plus all smaller angle experiments; 1.00 ± 0.05 when LSS constraints are included as well. The CMB alone currently gives weak constraints on Λ and moderate constraints on Ωtot, but theoretical forecasts of future long duration balloon and satellite experiments are shown which predict percent-level accuracy among a large fraction of the 10+ parameters characterizing the cosmic structure formation theory, at least if it is an inflation variant. PMID:9419321

  16. Experimental simulation of the atmospheric ablation of cosmic dust particles: implications for HPLA radar and lidar observations

    Science.gov (United States)

    Gomez Martin, Juan Carlos; Bones, David; Diego Carrillo Sanchez, Juan; James, Alexander; Janches, Diego; Plane, John

    2016-04-01

    The inner solar system is full of interplanetary dust particles (IDPs) originating from cometary trails and collisions between asteroids. The entry and evaporation of IDPs in planetary atmospheres is related to a variety of phenomena including formation of mesospheric metal layers and clouds and stratospheric aerosol chemistry. The estimated mass flux into the Earth's Atmosphere from modelling of Zodiacal Cloud observations combined with results from our chemical ablation model (CABMOD) is consistent with the deposition rate of cosmic spherules on the ice caps. However, the fluxes derived from modelling HPLA radar observations, which also uses CABMOD, are significantly lower. In addition, all models underestimate the observed Na/Fe ratio in metal layers observed by LIDAR, and the radar-based model in particular does not predict differential ablation. In order to address these inconsistencies, we have built a laboratory meteor ablation simulator, which enables us to observe and characterise the ablation of metal atoms from meteoritic IDP analogues. CABMOD can be then benchmarked against the laboratory data. In this presentation, the implications of our experimental results for the interpretation of radar field observations, mass flux estimates and modelling of metal layers will be discussed.

  17. Cosmic ray physics goes to school

    CERN Multimedia

    2002-01-01

    With the help of a CERN physicist, German Schools bring the Largest Cosmic Ray Detector in Europe one step closer to reality   Eric Berthier and Robert Porret (CERN, ST/HM), Frej Torp and Christian Antfolk from the Polytechnics Arcada in Finland, and Karsten Eggert, physicist at CERN who initiated this project, during the installation of cosmic ray detectors in the Pays de Gex, at point 4. Niina Patrikainen and Frej Torp, Finnish students from Rovaniemi and Arcada Polytechnics, installing cosmic ray counters at the Fachhochschule in Duesseldorf. The science of cosmic ray detection is growing, literally. Cosmic rays, energetic particles from space, strike our planet all the time. They collide with the air molecules in our upper atmosphere and initiate large showers of elementary particles (mainly electrons, photons, hadrons and muons) which rain down upon the earth. The shower size and the particle density in the showers reflect the initial energy of the cosmic ray particle, a detail which makes d...

  18. Cosmic ray penetration in diffuse clouds

    CERN Document Server

    Morlino, G

    2015-01-01

    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 $\\sim0.42$.

  19. Cosmic Connections:. from Cosmic Rays to Gamma Rays, Cosmic Backgrounds and Magnetic Fields

    Science.gov (United States)

    Kusenko, Alexander

    2013-12-01

    Combined data from gamma-ray telescopes and cosmic-ray detectors have produced some new surprising insights regarding intergalactic and galactic magnetic fields, as well as extragalactic background light. We review some recent advances, including a theory explaining the hard spectra of distant blazars and the measurements of intergalactic magnetic fields based on the spectra of distant sources. Furthermore, we discuss the possible contribution of transient galactic sources, such as past gamma-ray bursts and hypernova explosions in the Milky Way, to the observed ux of ultrahigh-energy cosmicrays nuclei. The need for a holistic treatment of gamma rays, cosmic rays, and magnetic fields serves as a unifying theme for these seemingly unrelated phenomena.

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

    CERN Document Server

    Kalashev, Oleg E; Essey, Warren

    2013-01-01

    The observed 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, these spectra would appear surprisingly hard, but the cosmic ray interactions generate very high energy gamma rays relatively close to the observer, and the spectra agree with the data. The same interactions of cosmic rays are expected to produce a flux of neutrinos with energies peaked around 1 PeV. We show that the predicted diffuse isotropic neutrino background from many distant sources can explain 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 a typical active galactic nucleus can accelerate protons to EeV energies.

  1. Cosmic Censorship: the Role of Quantum Physics

    OpenAIRE

    Hod, Shahar

    1999-01-01

    The cosmic censorship hypothesis introduced by Penrose thirty years ago is still one of the most important open questions in {\\it classical} general relativity. The main goal of this paper is to put forward the idea that cosmic censorship is intrinsically a {\\it quantum} phenomena. We construct a gedanken experiment which seems to violate the cosmic censorship principle within the purely {\\it classical} framework of general relativity. We prove, however, that {\\it quantum} physics restores th...

  2. On the Properties of Cosmic String Loops

    Science.gov (United States)

    Casper, Paul Henry

    1996-01-01

    When coupled with the prevailing ideas of cosmology, the standard model of particle physics implies that the early universe underwent a sequence of phase transitions. Such phase transitions can lead to topological defects such as magnetic monopoles, domain walls and cosmic strings. The formation and subsequent evolution of a network of cosmic strings may have played a key role in the development of the early universe. One of the most crucial elements in the evolution of the cosmic string network is the formation and decay of closed loops of cosmic string. After formation, the loops lose their energy by emitting gravitational radiation. This provides the primary energy loss mechanism for the cosmic string network. In addition, the cosmic string loops may display a number of observable features through which the cosmic string model may be constrained. In this dissertation a number of the key properties of cosmic string loops are investigated. A general method for determining the rates at which cosmic string loops radiate both energy and linear momentum is developed and implemented. Exact solutions for the radiation rates of a several new classes of loops are derived and used to test the validity of using the piecewise linear method on smooth loop trajectories. A large set of representative loop trajectories is produced using the method of loop fragmentation. These trajectories are analyzed to provide useful information on the properties of realistic cosmic string loops. The fraction of cosmic string loops which would collapse to form black holes is determined and used to place a new observational limit on the mass per unit length of cosmic strings.

  3. ACORDE - A Cosmic Ray Detector for ALICE

    CERN Document Server

    INSPIRE-00247175; Pagliarone, C.

    2006-01-01

    ACORDE, the ALICE COsmic Ray DEtector is one of the ALICE detectors, presently under construction. It consists of an array of plastic scintillator counters placed on the three upper faces of the ALICE magnet. This array will act as Level 0 cosmic ray trigger and, together with other ALICE sub-detectors, will provide precise information on cosmic rays with primary energies around $10^{15-17}$ eV. In this paper we will describe the ACORDE detector, trigger design and electronics.

  4. Interacting holographic generalized cosmic Chaplygin gas model

    Science.gov (United States)

    Naji, Jalil

    2014-03-01

    In this paper we consider a correspondence between the holographic dark energy density and interacting generalized cosmic Chaplygin gas energy density in flat FRW universe. Then, we reconstruct the potential of the scalar field which describe the generalized cosmic Chaplygin cosmology. In the special case we obtain time-dependent energy density and study cosmological parameters. We find stability condition of this model which is depend on cosmic parameter.

  5. Astronomers Unveiling Life's Cosmic Origins

    Science.gov (United States)

    2009-02-01

    Processes that laid the foundation for life on Earth -- star and planet formation and the production of complex organic molecules in interstellar space -- are yielding their secrets to astronomers armed with powerful new research tools, and even better tools soon will be available. Astronomers described three important developments at a symposium on the "Cosmic Cradle of Life" at the annual meeting of the American Association for the Advancement of Science in Chicago, IL. Chemistry Cycle The Cosmic Chemistry Cycle CREDIT: Bill Saxton, NRAO/AUI/NSF Full Size Image Files Chemical Cycle Graphic (above image, JPEG, 129K) Graphic With Text Blocks (JPEG, 165K) High-Res TIFF (44.2M) High-Res TIFF With Text Blocks (44.2M) In one development, a team of astrochemists released a major new resource for seeking complex interstellar molecules that are the precursors to life. The chemical data released by Anthony Remijan of the National Radio Astronomy Observatory (NRAO) and his university colleagues is part of the Prebiotic Interstellar Molecule Survey, or PRIMOS, a project studying a star-forming region near the center of our Milky Way Galaxy. PRIMOS is an effort of the National Science Foundation's Center for Chemistry of the Universe, started at the University of Virginia (UVa) in October 2008, and led by UVa Professor Brooks H. Pate. The data, produced by the NSF's Robert C. Byrd Green Bank Telescope (GBT) in West Virginia, came from more than 45 individual observations totalling more than nine GigaBytes of data and over 1.4 million individual frequency channels. Scientists can search the GBT data for specific radio frequencies, called spectral lines -- telltale "fingerprints" -- naturally emitted by molecules in interstellar space. "We've identified more than 720 spectral lines in this collection, and about 240 of those are from unknown molecules," Remijan said. He added, "We're making available to all scientists the best collection of data below 50 GHz ever produced for

  6. Dark Matter detection via lepton cosmic rays

    CERN Document Server

    Lineros, Roberto A

    2010-01-01

    Recent observations of lepton cosmic rays, coming from the PAMELA and FERMI experiments, have pushed our understanding of the interstellar medium and cosmic rays sources to unprecedented levels. The imprint of dark matter on lepton cosmic rays is the most exciting explanation of both PAMELA's positron excess and FERMI's total flux of electrons. Alternatively, supernovae are astrophysical objects with the same potential to explain these observations. In this work, we present an updated study of the astrophysical sources of lepton cosmic rays and the possible trace of a dark matter signal on the positron excess and total flux of electrons.

  7. Cosmic Ray Acceleration in Supernova Remnants

    CERN Document Server

    Blasi, Pasquale

    2010-01-01

    We review the main observational and theoretical facts about acceleration of Galactic cosmic rays in supernova remnants, discussing the arguments in favor and against a connection between cosmic rays and supernova remnants, the so-called supernova remnant paradigm for the origin of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of 1) magnetic field amplification, 2) acceleration of nuclei heavier than hydrogen, 3) presence of neutrals in the circumstellar environment. The status of the supernova-cosmic ray connection in the time of Fermi-LAT and Cherenkov telescopes is also discussed.

  8. High Energy Cosmic Electrons: Messengers from Nearby Cosmic Ray Sources or Dark Matter?

    Science.gov (United States)

    Moiseev, Alexander

    2011-01-01

    This slide presentation reviews the recent discoveries by the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-Ray Telescope in reference to high energy cosmic electrons, and whether their source is cosmic rays or dark matter. Specific interest is devoted to Cosmic Ray electrons anisotropy,

  9. Inside the cosmic mind archetypal astrology and the new cosmology

    CERN Document Server

    Wyss, Phoebe

    2014-01-01

    Phoebe Wyss, an experienced astrologer, here examines all aspects of astrology in the light of the emerging worldview known as archetypal cosmology.She sets out by exploring the classical roots of astrology in sources of wisdom found in the ancient Egyptian mysteries. She then follows the tradition to modern times through C.G. Jung''s ideas on the nature of the psyche. She also discovers that the claims of astrology are entirely compatible with new cosmological thinking as envisioned by post-modern physics and chaos theory.In the second part of the book, she proposes that the mathematical basis of astrology and the components of astrological charts are both archetypal and cosmic in scope. She argues that the twelve astrological archetypes make up a single ‘cosmic mind', whose patterns are imprinted on all our individual minds.Finally, she exemplifies this radical approach to astrology through an interpretation of the chart of William Blake.

  10. Interactions of Cosmic Rays in the Atmosphere: Growth Curves Revisited

    CERN Document Server

    Obermeier, A; Hörandel, J; Müller, D

    2013-01-01

    Measurements of cosmic-ray abundances on balloons are affected by interactions in the residual atmosphere above the balloon. Corrections for such interactions are particularly important for observations of rare secondary particles such as boron, antiprotons and positrons. These corrections can either be calculated if the relevant cross sections in the atmosphere are known, or may be empirically determined by extrapolation of the "growth curves", i. e. the individual particle intensities as functions of atmospheric depth. The growth-curve technique is particularly attractive for long-duration balloon flights where the periodic daily altitude variations permit rather precise determinations of the corresponding particle intensity variations. We determine growth curves for nuclei from boron (Z=5) to iron (Z=26), using data from the 2006 Arctic balloon flight of the TRACER detector for cosmic-ray nuclei, and we compare the growth curves with predictions from published cross section values. In general, good agreeme...

  11. Cosmic Microwave Background and Density Fluctuations from Strings plus Inflation

    CERN Document Server

    Contaldi, C; Magueijo, J; Contaldi, Carlo; Hindmarsh, Mark; Magueijo, Joao

    1999-01-01

    In cosmological models where local cosmic strings are formed at the end of a period of inflation, the perturbations are seeded both by the defects and by the quantum fluctuations. In a subset of these models, for example those based on $D$-term inflation, the amplitudes are similar. Using our recent calculations of structure formation with cosmic strings, we point out that in a flat cosmology with zero cosmological constant and 5% baryonic component, strings plus inflation fits the observational data much better than each component individually. The large-angle CMB spectrum is mildly tilted, for Harrison-Zeldovich inflationary fluctuations. It then rises to a thick Doppler bump, covering $\\ell=200-600$, modulated by soft secondary undulations. The standard CDM anti-biasing problem is cured, giving place to a slightly biased scenario of galaxy formation.

  12. Causes of Forbush decreases and other cosmic ray variations

    Science.gov (United States)

    Barouch, E.; Burlaga, L. F.

    1975-01-01

    The relationship between neutron monitor variations and the intensity variations of the interplanetary magnetic field is studied by using Deep River data and Imp series satellite data. In over 80% of the cases studied in 1968, identifiable depressions of the cosmic ray intensity are associated with magnetic field enhancements of several hours duration and intensity above 10 gamma. Conversely, almost every magnetic field enhancement has an identifiable effect (though not necessarily a marked depression) on the cosmic ray intensity. Perpendicular gradient drifts are suggested as one possible mechanism producing the individual decreases, and some ideas on the recovery processes are presented. Long-lasting Forbush decreases are found to be the consequence of the action of several successive magnetic field enhancements. Evidence is presented that indicates that most of these enhancements are caused by the steepening of streams in interplanetary space.

  13. Multiple Cosmic Collisions and the Microwave Background Power Spectrum

    CERN Document Server

    Kozaczuk, Jonathan

    2012-01-01

    Collisions between cosmic bubbles of different vacua are a generic feature of false vacuum eternal inflation scenarios. While previous studies have focused on the consequences of a single collision event in an observer's past, we begin here an investigation of the more general scenario allowing for many "mild" collisions intersecting our past light cone (and one another). We discuss the general features of multiple collision scenarios and consider their impact on the cosmic microwave background (CMB) temperature power spectrum, treating the collisions perturbatively. In a large class of models, one can approximate a multiple collision scenario as a superposition of individual collision events governed by nearly isotropic and scale-invariant distributions, most appearing to take up less than half of the sky. In this case, the shape of the expected CMB temperature spectrum maintains statistical isotropy and typically features a dramatic increase in power in the low multipoles relative to that of the best-fit $\\...

  14. About cosmic gamma ray lines

    Science.gov (United States)

    Diehl, Roland

    2017-06-01

    Gamma ray lines from cosmic sources convey the action of nuclear reactions in cosmic sites and their impacts on astrophysical objects. Gamma rays at characteristic energies result from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. The gamma-ray line from the annihilation of positrons at 511 keV falls into the same energy window, although of different origin. We present here the concepts of cosmic gamma ray spectrometry and the corresponding instruments and missions, followed by a discussion of recent results and the challenges and open issues for the future. Among the lessons learned are the diffuse radioactive afterglow of massive-star nucleosynthesis in 26Al and 60Fe gamma rays, which is now being exploited towards the cycle of matter driven by massive stars and their supernovae; large interstellar cavities and superbubbles have been recognised to be of key importance here. Also, constraints on the complex processes making stars explode as either thermonuclear or core-collapse supernovae are being illuminated by gamma-ray lines, in this case from shortlived radioactivities from 56Ni and 44Ti decays. In particular, the three-dimensionality and asphericities that have recently been recognised as important are enlightened in different ways through such gamma-ray line spectroscopy. Finally, the distribution of positron annihilation gamma ray emission with its puzzling bulge-dominated intensity disctribution is measured through spatially-resolved spectra, which indicate that annihilation conditions may differ in different parts of our Galaxy. But it is now understood that a variety of sources may feed positrons into the interstellar medium, and their characteristics largely get lost during slowing down and propagation of positrons before annihilation; a recent microquasar flare was caught as an opportunity to see positrons annihilate at a source.

  15. Cosmic Shear Bias and Calibration in Cosmic Shear Studies

    CERN Document Server

    Taylor, A N

    2016-01-01

    With the advent of large-scale weak lensing surveys there is a need to understand how realistic, scale-dependent systematics bias cosmic shear and dark energy measurements, and how they can be removed. Here we describe how spatial variations in the amplitude and orientation of realistic image distortions convolve with the measured shear field, mixing the even-parity convergence and odd-parity modes, and bias the shear power spectrum. Many of these biases can be removed by calibration to external data, the survey itself, or by modelling in simulations. The uncertainty in the calibration must be marginalised over and we calculate how this propagates into parameter estimation, degrading the dark energy Figure-of-Merit. We find that noise-like biases affect dark energy measurements the most, while spikes in the bias power have the least impact, reflecting their correlation with the effect of cosmological parameters. We argue that in order to remove systematic biases in cosmic shear surveys and maintain statistica...

  16. Gravitational entropy of cosmic expansion

    CERN Document Server

    Sussman, Roberto A

    2014-01-01

    We apply a recent proposal to define "gravitational entropy" to the expansion of cosmic voids within the framework of non-perturbative General Relativity. By considering CDM void configurations compatible with basic observational constraints, we show that this entropy grows from post-inflationary conditions towards a final asymptotic value in a late time fully non-linear regime described by the Lemaitre-Tolman-Bondi (LTB) dust models. A qualitatively analogous behavior occurs if we assume a positive cosmological constant consistent with a $\\Lambda$-CDM background model. However, the $\\Lambda$ term introduces a significant suppression of entropy growth with the terminal equilibrium value reached at a much faster rate.

  17. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...... between cosmic ray flux and low cloud top temperature. The temperature of a cloud depends on the radiation properties determined by its droplet distribution. Low clouds are warm (> 273 K) and therefore consist of liquid water droplets. At typical atmospheric supersaturations (similar to1%) a liquid cloud...

  18. International Conference on Cosmic Rays

    CERN Multimedia

    W.O. LOCK

    1964-01-01

    Towards the end of last year the 8th International conference on cosmic rays, held under the auspices of the International Union of Pure and Applied Physics (I.U.P.A.P.) and the Department of Atomic Energy of the Government of India, was held at Jaipur, India. Among the participants was W.O. Lock, head of CERN's Emulsion Group, who gave an invited talk on recent work in the field of what is normally known as high-energy physics — though in the context of this conference such energies seem quite low. In this article, Dr. Lock gives a general review of the conference and of the subjects discussed.

  19. Cosmic polarimetry in magnetoactive plasmas

    CERN Document Server

    Giovannini, Massimo

    2009-01-01

    Polarimetry of the Cosmic Microwave Background (CMB) represents one of the possible diagnostics aimed at testing large-scale magnetism at the epoch of the photon decoupling. The propagation of electromagnetic disturbances in a magnetized plasma leads naturally to a B-mode polarization whose angular power spectrum is hereby computed both analytically and numerically. Combined analyses of all the publicly available data on the B-mode polarization are presented, for the first time, in the light of the magnetized $\\Lambda$CDM scenario. Novel constraints on pre-equality magnetism are also derived in view of the current and expected sensitivities to the B-mode polarization.

  20. The Cosmic Background Explorer Satellite

    Science.gov (United States)

    Mather, J.; Kelsall, T.

    1980-01-01

    The Cosmic Background Explorer (COBE) satellite, planned for launch in 1985, will measure the diffuse infrared and microwave radiation of the universe over the entire wavelength range from a few microns to 1.3 cm. It will include three instruments: a set of microwave isotropy radiometers at 23, 31, 53, and 90 GHz, an interferometer spectrometer from 1 to 100/cm, and a filter photometer from 1 to 300 microns. The COBE satellite is designed to reach the sensitivity limits set by foreground sources such as the interstellar and interplanetary dust, starlight, and galactic synchrotron radiation, so that a diffuse residual radiation may be interpreted unambiguously as extragalactic

  1. Ground level cosmic ray observations

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, S.A. [Tata Institute of Fundamental Research, Bombay (International Commission on Radiation Units and Measurements); Grimani, C.; Brunetti, M.T.; Codino, A. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Papini, P.; Massimo Brancaccio, F.; Piccardi, S. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Basini, G.; Bongiorno, F. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Golden, R.L. [New Mexico State Univ., Las Cruces, NM (United States). Particle Astrophysics Lab.; Hof, M. [Siegen Univ. (Germany). Fachbereich Physik

    1995-09-01

    Cosmic rays at ground level have been collected using the NMSU/Wizard - MASS2 instrument. The 17-hr observation run was made on September 9. 1991 in Fort Sumner, New Mexico, Usa. Fort Sumner is located at 1270 meters a.s.l., corresponding to an atmospheric depth of about 887 g/cm{sup 2}. The geomagnetic cutoff is 4.5 GV/c. The charge ratio of positive and negative muons and the proton to muon ratio have been determined. These observations will also be compared with data collected at a higher latitude using the same basic apparatus.

  2. The cosmic production of Helium

    CERN Document Server

    Jiménez, R; MacDonald, J; Gibson, B K; Jimenez, Raul; Flynn, Chris; Donald, James Mac; Gibson, Brad K.

    2003-01-01

    We estimate the cosmic production rate of helium relative to metals ($\\Delta Y/\\Delta Z$) using K dwarf stars in the Hipparcos catalog with accurate spectroscopic metallicities. The best fitting value is $\\Delta Y/\\Delta Z=2.1 \\pm 0.4$ at the 68% confidence level. Our derived value agrees with determinations from HII regions and with theoretical predictions from stellar yields with standard assumptions for the initial mass function. The amount of helium in stars determines how long they live and therefore how fast they will enrich the insterstellar medium with fresh material.

  3. The Cosmic Ray Lepton Puzzle

    CERN Document Server

    Brun, Pierre; Cirelli, Marco; Moulin, Emmanuel; Glicenstein, Jean-Francois; Iocco, Fabio; Pieri, Lidia

    2010-01-01

    Recent measurements of cosmic ray electrons and positrons by PAMELA, ATIC, Fermi and HESS have revealed interesting excesses and features in the GeV-TeV range. Many possible explanations have been suggested, invoking one or more nearby primary sources such as pulsars and supernova remnants, or dark matter. Based on the output of the TANGO in PARIS --Testing Astroparticle with the New GeV/TeV Observations in Positrons And electRons : Identifying the Sources-- workshop held in Paris in May 2009, we review here the latest experimental results and we discuss some virtues and drawbacks of the many theoretical interpretations proposed so far.

  4. History of cosmic ray research in Finland

    Science.gov (United States)

    Usoskin, I. G.; Valtonen, E.; Vainio, R.; Tanskanen, P. J.; Aurela, A. M.

    2009-11-01

    The history of cosmic ray research in Finland can be traced back to the end of 1950s, when first ground-based cosmic ray measurements started in Turku. The first cosmic ray station was founded in Oulu in 1964 performing measurements of cosmic rays by a muon telescope, which was later complemented by a neutron monitor. Since the 1990s, several research centers and universities, such as The Finnish Meteorological Institute, Helsinki University of Technology, University of Oulu, University of Turku and University of Helsinki have been involved in space science projects, such as SOHO, AMS, Cluster, Cassini, BepiColombo, etc. At the same time, ground-based cosmic ray measurements have reached a new level, including a fully automatic on-line database in Oulu and a new muon measuring underground site in Pyhäsalmi. Research groups in Helsinki, Oulu and Turku have also extensive experience in theoretical investigations of different aspects of cosmic ray physics. Cosmic ray research has a 50-year long history in Finland, covering a wide range from basic long-running ground-based observations to high-technology space-borne instrumentation and sophisticated theoretical studies. Several generations of researchers have been involved in the study ensuring transfer of experience and building the recognized Finnish research school of cosmic ray studies.

  5. The Spine of the Cosmic Web

    NARCIS (Netherlands)

    Aragón-Calvo, Miguel A.; Platen, Erwin; van de Weijgaert, Rien; Szalay, Alexander S.

    2010-01-01

    We present the SpineWeb framework for the topological analysis of the Cosmic Web and the identification of its walls, filaments, and cluster nodes. Based on the watershed segmentation of the cosmic density field, the SpineWeb method invokes the local adjacency properties of the boundaries between th

  6. NEXUS: tracing the cosmic web connection

    NARCIS (Netherlands)

    Cautun, Marius; van de Weygaert, Rien; Jones, Bernard J. T.

    2013-01-01

    We introduce the NEXUS algorithm for the identification of cosmic web environments: clusters, filaments, walls and voids. This is a multiscale and automatic morphological analysis tool that identifies all the cosmic structures in a scale free way, without preference for a certain size or shape. We d

  7. The Temperature of the Cosmic Microwave Background

    CERN Document Server

    Fixsen, D J

    2009-01-01

    The FIRAS data are independently recalibrated using the WMAP data to obtain a CMB temperature of 2.7260 +/- 0.0013. Measurements of the temperature of the cosmic microwave background are reviewed. The determination from the measurements from the literature is cosmic microwave background temperature of 2.72548 +/- 0.00057 K.

  8. Cosmic-ray acceleration in supernova remnants

    NARCIS (Netherlands)

    Helder, E.A.

    2010-01-01

    Supernovae are among the most energetic events in the Universe. During the event, they expel their material with enormous speeds into the surroundings. In addition, supernovae are thought to transfer a sizable fraction of their energy into just a few particles: cosmic rays. These cosmic rays acquire

  9. Cosmic rays: a review for astrobiologists.

    Science.gov (United States)

    Ferrari, Franco; Szuszkiewicz, Ewa

    2009-05-01

    Cosmic rays represent one of the most fascinating research themes in modern astronomy and physics. Significant progress is being made toward an understanding of the astrophysics of the sources of cosmic rays and the physics of interactions in the ultrahigh-energy range. This is possible because several new experiments in these areas have been initiated. Cosmic rays may hold answers to a great number of fundamental questions, but they also shape our natural habitat and influence the radiation environment of our planet Earth. The importance of the study of cosmic rays has been acknowledged in many fields, including space weather science and astrobiology. Here, we concentrate on the astrobiological aspects of cosmic rays with regard to the enormous amount of new data available, some of which may, in fact, improve our knowledge about the radiation of cosmic origin on Earth. We focus on fluxes arriving at Earth and doses received, and will guide the reader through the wealth of scientific literature on cosmic rays. We have prepared a concise and self-contained source of data and recipes useful for performing interdisciplinary research in cosmic rays and their effects on life on Earth.

  10. The Pierre Auger Cosmic Ray Observatory

    NARCIS (Netherlands)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albert, J. N.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Batista, R. Alves; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Aranda, V. M.; Argiro, S.; Arisaka, K.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Awal, N.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A.; Barenthien, N.; Barkhausen, M.; Baeuml, J.; Baus, C.; Beatty, J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bergmann, T.; Bertaina, M. E.; Biermann, P. L.; Bilhaut, R.; Billoir, P.; Blaes, S. G.; Blanco, M.; Bleve, C.; Bluemer, H.; Bohacova, M.; Bolz, H.; Boncioli, D.; Bonifaz, C.; Bonino, R.; Boratav, M.; Borodai, N.; Bracci, F.; 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.; Camin, D.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Castera, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chiosso, M.; Chudoba, J.; Cilmo, M.; Clark, P. D. J.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Colombo, E.; Colonges, S.; Coluccia, M. R.; Conceicao, R.; Contreras, F.; Cooper, M. J.; Coppens, J.; Cordier, A.; Courty, B.; 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 Donato, C.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Diaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, C.; Dolron, P.; Dorofeev, A.; Hasankiadeh, Q. Dorosti; Dova, M. T.; D'Urso, D.; Ebr, J.; Engel, R.; Epele, L. N.; 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.; Ferrero, A.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipcic, A.; Fox, B. D.; Fraenkel, E. D.; Fratu, O.; Freire, M. M.; Froehlich, U.; Fuchs, B.; Fulgione, W.; Fujii, T.; Garcia, B.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Geenen, H.; Gemmeke, H.; Genolini, B.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Gibbs, K.; Giller, M.; Giudice, N.; Glaser, C.; Glass, H.; Gomez Berisso, M.; Gomez Vitale, P. F.; Goncalves, P.; Gonzalez, J. G.; Gonzalez, N.; Gookin, B.; Gora, D.; Gordon, J.; Gorgi, A.; Gorham, P.; Gotink, W.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Grygar, J.; Guardone, N.; Guarino, F.; Guedes, G. P.; Guglielmi, L.; Habraken, R.; Hampel, M. R.; Hansen, P.; Harari, D.; Harmsma, S.; 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.; Hoerandel, J. R.; Horneffer, A.; Horvat, M.; Horvath, P.; Hrabovsky, M.; Huber, D.; Hucker, H.; Huege, T.; Iarlori, M.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Johnsen, J. A.; Josebachuili, M.; Kaeaepae, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kegl, B.; Keilhauer, B.; Keivani, A.; Kelley, J.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Kopmann, A.; Krause, R.; Krohm, N.; Kroemer, O.; Kuempel, D.; Kunka, N.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leao, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopez, R.; Lopez Casado, A.; 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.; Maris, I. C.; Marsella, G.; Martello, D.; Martina, L.; Martinez, H.; Martinez, N.; Martinez Bravo, O.; Martraire, D.; Masias 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.; Mello, V. B. B.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Micanovic, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Montanet, F.; Morello, C.; Mostafa, M.; Moura, C. A.; Muller, M. A.; Mueller, G.; Mueller, S.; Muenchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Nicotra, D.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nozka, L.; Ochilo, L.; Ohnuki, T.; Oikonomou, F.; Olinto, A.; Oliveira, M.; Olmos-Gilbaja, V. M.; Pacheco, N.; PakkSelmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Patel, M.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrinca, P.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Porter, T.; Pouryamout, J.; Pouthas, J.; Prado, R. R.; Privitera, P.; Prouza, M.; Pryke, C. L.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Randriatoamanana, R.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenua, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Robbins, S.; Roberts, M.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodriguez-Frias, M. D.; Rogozin, D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovanek, P.; Schreuder, F.; Schroeder, F. G.; Schulz, A.; Schulz, J.; Schuessler, F.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Sequeiros, G.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Smialkowski, A.; Smida, R.; Smith, A. G. K.; Snow, G. R.; Sommers, P.; Sorokin, J.; Speelman, R.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanic, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijaervi, T.; Supanitsky, A. D.; Sutherland, M. S.; Sutter, M.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tcherniakhovski, D.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tome, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Trung, T. N.; Tunnicliffe, V.; Tusi, E.; Ulrich, R.; Unger, M.; Urban, M.; Valdes Galicia, J. F.; Valino, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cardenas, B.; Varnav, D. M.; Varner, G.; Vasquez, R.; Vazquez, J. R.; Vazquez, R. A.; Veberic, D.; Verkooijen, H.; Verzi, V.; Vicha, J.; Videla, M.; Villasenor, L.; Vitali, G.; Vlcek, B.; Vorenholt, H.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wainberg, O.; Walker, P.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Widom, A.; Wiebusch, C.; Wiencke, L.; Wijnen, T.; Wilczynska, B.; Wilczynski, H.; Wild, N.; Winchen, T.; Wittkowski, D.; Woerner, G.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zhou, J.; Zhu, Y.; Silva, M. Zimbres; Zimmermann, B.; Ziolkowski, M.; Zuccarello, F.

    2015-01-01

    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 par

  11. Cosmic perspectives in space physics

    CERN Document Server

    Biswas, Sukumar

    2000-01-01

    In the early years of the twentieth century, Victor Hess of Germany flew instruments in balloons and so discovered in 1912 that an extra-~errestial radiation of unknown origin is incident on the earth with an almost constant intensity at all times. These penetrating non­ solar radiations which were called Cosmic Rays by Millikan, USA, opened the new frontier of space physics and many leading scientists were attracted to it. At the end of World War II a number of space vehicles, e.g. stratospheric balloons, rockets and satellites were developed. In 1950 and onwards, these vehicles enabled spectacular advances in space physics and space astrophysics. New horizons were opened in the explorations of cosmic rays, the earth's magnetosphere, the Sun and the heliosphere, the moon and the planets. Using space-borne instruments, exciting discoveries were made of stars, and galaxies in the infra-red, ultra violet, x-ray and gamma-ray wavelengths. In this text book these fascinating new findings are presented in depth a...

  12. The Cosmic Infrared Background Experiment

    CERN Document Server

    Bock, J; Cooray, A R; Kawada, M; Keating, B; Lange, A; Lee, D H; Matsumoto, T; Matsuura, S; Pak, S; Renbarger, T; Sullivan, I; Tsumura, K; Wada, T; Watabe, T; Bock, James; Battle, John; Cooray, Asantha; Kawada, Mitsunobu; Keating, Brian; Lange, Andrew; Lee, Dae-Hea; Matsumoto, Toshio; Matsuura, Shuji; Pak, Soojong; Renbarger, Tom; Sullivan, Ian; Tsumura, Kohji; Wada, Takehiko; Watabe, Toyoki

    2006-01-01

    We are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The cameras will search for spatial fluctuations in the background on angular scales from 7 arcseconds to 2 degrees over a range of angular scales poorly covered by previous experiments. CIBER will determine if the fluctuations reported by the IRTS arise from first-light galaxies or have a local origin. In a short rocket flight CIBER has sensitivity to probe fluctuations 100 times fainter than IRTS/DIRBE. By jointly observing regions of the sky studied by Spitzer and ASTRO-F, CIBER will build a multi-color view of the near-infrared background, accurately assessing the contribution of local (z = 1-3) galaxies to the observed background fluctuations, allowing a de...

  13. The Limits of Cosmic Shear

    CERN Document Server

    Kitching, Thomas D; Heavens, Alan F; Jimenez, Raul; McEwen, Jason D; Verde, Licia

    2016-01-01

    In this paper we discuss the commonly-used approximations for two-point cosmic shear statistics. We discuss the four most prominent assumptions in this statistic: the flat-sky, tomographic, Limber and configuration-space approximations, that the vast majority of cosmic shear results to date have used simultaneously. Of these approximations we find that the flat-sky approximation suppresses power by >1% on scales of l5% on scales l<100; in doing so we find an l-dependent factor that has been neglected in analyses to date. To investigate the impact of these approximations we reanalyse the CFHTLenS 2D correlation function results. When using all approximations we reproduce the result that measurements of the matter power spectrum amplitude are in tension with measurements from the CMB Planck data: where a conditional value of sigma8=0.789 +/- 0.015 is found from CFHTLenS and sigma8=0.830 +/- 0.015 from Planck. When we do not use the Limber and flat-sky approximations we find a conditional value of sigma8=0.80...

  14. Neutrino mass without cosmic variance

    CERN Document Server

    LoVerde, Marilena

    2016-01-01

    Measuring the absolute scale of the neutrino masses is one of the most exciting opportunities available with near-term cosmological datasets. Two quantities that are sensitive to neutrino mass, scale-dependent halo bias $b(k)$ and the linear growth parameter $f(k)$ inferred from redshift-space distortions, can be measured without cosmic variance. Unlike the amplitude of the matter power spectrum, which always has a finite error, the error on $b(k)$ and $f(k)$ continues to decrease as the number density of tracers increases. This paper presents forecasts for statistics of galaxy and lensing fields that are sensitive to neutrino mass via $b(k)$ and $f(k)$. The constraints on neutrino mass from the auto- and cross-power spectra of spectroscopic and photometric galaxy samples are weakened by scale-dependent bias unless a very high density of tracers is available. In the high density limit, using multiple tracers allows cosmic-variance to be beaten and the forecasted errors on neutrino mass shrink dramatically. In...

  15. Improving cosmic string network simulations

    Science.gov (United States)

    Hindmarsh, Mark; Rummukainen, Kari; Tenkanen, Tuomas V. I.; Weir, David J.

    2014-08-01

    In real-time lattice simulations of cosmic strings in the Abelian Higgs model, the broken translational invariance introduces lattice artifacts; relativistic strings therefore decelerate and radiate. We introduce two different methods to construct a moving string on the lattice, and study in detail the lattice effects on moving strings. We find that there are two types of lattice artifact: there is an effective maximum speed with which a moving string can be placed on the lattice, and a moving string also slows down, with the deceleration approximately proportional to the exponential of the velocity. To mitigate this, we introduce and study an improved discretization, based on the tree-level Lüscher-Weisz action, which is found to reduce the deceleration by an order of magnitude, and to increase the string speed limit by an amount equivalent to halving the lattice spacing. The improved algorithm is expected to be very useful for 3D simulations of cosmic strings in the early Universe, where one wishes to simulate as large a volume as possible.

  16. Improving cosmic string network simulations

    CERN Document Server

    Hindmarsh, Mark; Tenkanen, Tuomas V I; Weir, David J

    2014-01-01

    In real-time lattice simulations of cosmic strings in the Abelian Higgs model, the broken translational invariance introduces lattice artefacts; relativistic strings therefore decelerate and radiate. We introduce two different methods to construct a moving string on the lattice, and study in detail the lattice effects on moving strings. We find that there are two types of lattice artefact: there is an effective maximum speed with which a moving string can be placed on the lattice, and a moving string also slows down, with the deceleration approximately proportional to the exponential of the velocity. To mitigate this, we introduce and study an improved discretisation, based on the tree-level L\\"{u}scher-Weisz action, which is found to reduce the deceleration by an order of magnitude, and to increase the string speed limit by an amount equivalent to halving the lattice spacing. The improved algorithm is expected to be very useful for 3D simulations of cosmic strings in the early universe, where one wishes to s...

  17. Cosmic rays: extragalactic and Galactic

    CERN Document Server

    Istomin, Ya N

    2014-01-01

    From the analysis of the flux of high energy particles, $E>3\\cdot 10^{18}eV$, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, ${\\bar q}(E)\\propto E^{-2.7}$, with the same index of $2.7$ that has the distribution of Galactic cosmic rays before so called 'knee', $E3\\cdot 10^{15}eV$, from the Galaxy because of the dependence of the coefficient of diffusion of cosmic rays on energy, $D\\propto E^{0.7}$. The obtained index of the density distribution of particles over energy, $N(E)\\propto E^{-2.7-0.7/2}=E^{-3.05}$, for $E>3\\cdot 10^{15}eV$ agrees well with the observed one, $N(E)\\propto E^{-3.1}$. Estimated time of termination of the jet in the Galaxy is $4.2\\cdot 10^{4}$ years ago.

  18. High energy physics in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-07

    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.

  19. Anisotropy and Corotation of Galactic Cosmic Rays

    CERN Document Server

    Amenomori, M; Bi, X J; Chen, D; Cui, S W; Danzengluobu; Ding, L K; Ding, X H; Feng Cun Feng; Zhaoyang Feng; Feng, Z Y; Gao, X Y; Geng, Q X; Guo, H W; He, H H; He, M; Hibino, K; Hotta, N; Haibing, H; Hu, H B; Huang, J; Huang, Q; Jia, H Y; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren; Le, G M; Li, A F; Li, J Y; Lou, Y Q; Lü, H; Lu, S L; Meng, X R; Mizutani, K; Mu, J; Munakata, K; Nagai, A; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ouchi, T; Ozawa, S; Ren, J R; Saitô, T; Saito, T Y; Sakata, M; Sako, T K; Sasaki, T; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, B; Wang, H; Wang, X; Wang, Y G; Wu, H R; Xue Liang; Yamamoto, Y; Yan, C T; Yang, X C; Yasue, S; Ye, Z H; Yu, G C; Yuan, A F; Yuda, T; Zhang, H M; Zhang, J L; Zhang, N J; Zhang, X Y; Zhang, Y; Zhaxisangzhu; Zhou, X X

    2006-01-01

    The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

  20. Cosmic ray physics with ACORDE at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pagliarone, C [Universita degli Studi di Cassino and INFN Pisa, Largo B. Pontecorvo, 3 - Pisa (Italy); Fernandez-Tellez, A [Benemerita Universidad Autonoma de Puebla (BUAP), Puebla (Mexico)], E-mail: pagliarone@fnal.gov

    2008-05-15

    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 2{center_dot}10{sup 10} to 2{center_dot} 10{sup 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{sup 15} to 10{sup 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.

  1. Heavy precipitation episodes and cosmic rays variation

    Directory of Open Access Journals (Sweden)

    A. Mavrakis

    2006-01-01

    Full Text Available In this paper an attempt is made to investigate the possible temporal correlation between heavy precipitation episodes and cosmic rays' activity, on various time scales. Cosmic rays measurements are sparse and cover less extended periods than those of precipitation. Precipitation is largely influenced by local climatic and even physiographic conditions, while cosmic rays' distribution is far more uniform over an area. Thus, in an effort to cover a larger range of climatic characteristics, each cosmic rays station was correlated with several nearby precipitation stations. Selected statistical methods were employed for the data processing. The analysis was preformed on annual, seasonal, monthly and daily basis whenever possible. Wet and dry regions and/or seasons seem to present a different response of precipitation to cosmic rays variations. Also Forbush decreases in most cases will not lead to heavy precipitation, yet this might be sensitive to precipitable water availability.

  2. Cosmic Physics: The High Energy Frontier

    CERN Document Server

    Stecker, F W

    2003-01-01

    Cosmic rays have been observed up to energies $10^8$ times larger than those of the best particle accelerators. Studies of astrophysical particles (hadrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. Thus, the cosmic high energy frontier is the nexus to new particle physics. This overview discusses recent advances being made in the physics and astrophysics of cosmic rays and cosmic gamma-rays at the highest observed energies as well as the related physics and astrophysics of very high energy cosmic neutrinos. These topics touch on questions of grand unification, violation of Lorentz invariance, as well as Planck scale physics and quantum gravity.

  3. Cosmic Ray Physics with ACORDE at LHC

    CERN Document Server

    Pagliarone, C.

    2008-01-01

    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.

  4. Cosmic ray escape from supernova remnants

    CERN Document Server

    Gabici, Stefano

    2011-01-01

    Galactic cosmic rays are believed to be accelerated at supernova remnants via diffusive shock acceleration. Though this mechanism gives fairly robust predictions for the spectrum of particles accelerated at the shock, the spectrum of the cosmic rays which are eventually injected in the interstellar medium is more uncertain and depends on the details of the process of particle escape from the shock. Knowing the spectral shape of these escaping particles is of crucial importance in order to assess the validity of the supernova remnant paradigm for cosmic ray origin. Moreover, after escaping from a supernova remnant, cosmic rays interact with the surrounding ambient gas and produce gamma rays in the vicinity of the remnant itself. The detection of this radiation can be used as an indirect proof of the fact that the supernova remnant was indeed accelerating cosmic rays in the past.

  5. Cosmic Ray Removal in Fiber Spectroscopic Image

    Science.gov (United States)

    Bai, Zhongrui; Zhang, Haotong; Yuan, Hailong; Carlin, Jeffrey L.; Li, Guangwei; Lei, Yajuan; Dong, Yiqiao; Yang, Huiqin; Zhao, Yongheng; Cao, Zihuang

    2017-02-01

    Single-exposure spectra in large spectral surveys are valuable for time domain studies such as stellar variability, but there is no available method to eliminate cosmic rays for single-exposure, multi-fiber spectral images. In this paper, we describe a new method to detect and remove cosmic rays in multi-fiber spectroscopic single exposures. Through the use of two-dimensional profile fitting and a noise model that considers the position-dependent errors, we successfully detect as many as 80% of the cosmic rays and correct the cosmic ray polluted pixels to an average accuracy of 97.8%. Multiple tests and comparisons with both simulated data and real LAMOST data show that the method works properly in detection rate, false detection rate, and validity of cosmic ray correction.

  6. Status of cosmic-ray antideuteron searches

    CERN Document Server

    von Doetinchem, P; Boggs, S; Bufalino, S; Dal, L; Donato, F; Fornengo, N; Fuke, H; Grefe, M; Hailey, C; Hamilton, B; Ibarra, A; Mitchell, J; Mognet, I; Ong, R A; Pereira, R; Perez, K; Putze, A; Raklev, A; Salati, P; Sasaki, M; Tarle, G; Urbano, A; Vittino, A; Wild, S; Xue, W; Yoshimura, K

    2015-01-01

    The precise measurement of cosmic-ray antiparticles serves as important means for identifying the nature of dark matter. Recent years showed that identifying the nature of dark matter with cosmic-ray positrons and higher energy antiprotons is difficult, and has lead to a significantly increased interest in cosmic-ray antideuteron searches. Antideuterons may also be generated in dark matter annihilations or decays, offering a potential breakthrough in unexplored phase space for dark matter. Low-energy antideuterons are an important approach because the flux from dark matter interactions exceeds the background flux by more than two orders of magnitude in the low-energy range for a wide variety of models. This review is based on the "dbar14 - dedicated cosmic-ray antideuteron workshop", which brought together theorists and experimentalists in the field to discuss the current status, perspectives, and challenges for cosmic-ray antideuteron searches and discusses the motivation for antideuteron searches, the theor...

  7. Cosmic Ray transport in turbulent magnetic field

    CERN Document Server

    Yan, Huirong

    2013-01-01

    Cosmic ray (CR) transport and acceleration is determined by the properties of magnetic turbulence. Recent advances in MHD turbulence call for revisions in the paradigm of cosmic ray transport. We use the models of magnetohydrodynamic turbulence that were tested in numerical simulation, in which turbulence is injected at large scale and cascades to to small scales. We shall address the issue of the transport of CRs, both parallel and perpendicular to the magnetic field. We shall demonstrate compressible fast modes are dominant cosmic ray scatterer from both quasilinear and nonlinear theories. We shall also show that the self-generated wave growth by CRs are constrained by preexisting turbulence and discuss the process in detail in the context of shock acceleration at supernova remnants and their implications. In addition, we shall dwell on the nonlinear growth of kinetic gyroresonance instability of cosmic rays induced by large scale compressible turbulence. This gyroresonance of cosmic rays on turbulence is d...

  8. Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

    Science.gov (United States)

    Pierre Auger Collaboration; Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez-Muñiz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Anzalone, A.; Aramo, C.; Argirò, S.; Arisaka, K.; Armengaud, E.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Atulugama, B. S.; Aublin, J.; Ave, M.; Avila, G.; Bäcker, T.; Badagnani, D.; Barbosa, A. F.; Barnhill, D.; Barroso, S. L. C.; Bauleo, P.; Beatty, J. J.; Beau, T.; Becker, B. R.; Becker, K. H.; Bellido, J. A.; Benzvi, S.; Berat, C.; Bergmann, T.; Bernardini, P.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Blasi, P.; Bleve, C.; Blümer, H.; Boháčová, M.; Bonifazi, C.; Bonino, R.; Brack, J.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Cai, B.; Camin, D. V.; Caramete, L.; Caruso, R.; Carvalho, W.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chye, J.; Clay, R. W.; Colombo, E.; Conceição, R.; Connolly, B.; Contreras, F.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Donato, C.; de Jong, S. J.; de La Vega, G.; de Mello, W. J. M.; de Mello Neto, J. R. T.; de Mitri, I.; de Souza, V.; Del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; di Giulio, C.; Diaz, J. C.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dornic, D.; Dorofeev, A.; Dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Duvernois, M. A.; Engel, R.; Epele, L.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; San Luis, P. Facal; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrer, F.; Ferry, S.; Fick, B.; Filevich, A.; Filipčič, A.; Fleck, I.; Fracchiolla, C. E.; Fulgione, W.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Geenen, H.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Herrero, R.; Gonçalves, P.; Gonçalves Do Amaral, M.; Gonzalez, D.; Gonzalez, J. G.; González, M.; Góra, D.; Gorgi, A.; Gouffon, P.; Grassi, V.; Grillo, A. F.; Grunfeld, C.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Gutiérrez, J.; Hague, J. D.; Hamilton, J. C.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hauschildt, T.; Healy, M. D.; Hebbeker, T.; Hebrero, G.; Heck, D.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hörandel, J.; Horneffer, A.; Horvat, M.; Hrabovský, M.; Huege, T.; Hussain, M.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kégl, B.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D.-H.; Krieger, A.; Krömer, O.; Kuempel, D.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lebrun, D.; Lebrun, P.; Lee, J.; de Oliveira, M. A. Leigui; Letessier-Selvon, A.; Leuthold, M.; Lhenry-Yvon, I.; López, R.; Lopez Agüera, A.; Lozano Bahilo, J.; García, R. Luna; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mancarella, G.; Manceñido, M. E.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Maris, I. C.; Falcon, H. R. Marquez; Martello, D.; Martínez, J.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McCauley, T.; McEwen, M.; McNeil, R. R.; Medina, M. C.; Medina-Tanco, G.; Meli, A.; Melo, D.; Menichetti, E.; Menschikov, A.; Meurer, Chr.; Meyhandan, R.; Micheletti, M. I.; Miele, G.; Miller, W.; Mollerach, S.; Monasor, M.; Ragaigne, D. Monnier; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Morris, C.; Mostafá, M.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Newman-Holmes, C.; Newton, D.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Ohnuki, T.; Olinto, A.; Olmos-Gilbaja, V. M.; Ortiz, M.; Ortolani, F.; Ostapchenko, S.; Otero, L.; Pacheco, N.; Selmi-Dei, D. Pakk; Palatka, M.; Pallotta, J.; Parente, G.; Parizot, E.; Parlati, S.; Pastor, S.; Patel, M.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; PȩKala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petrera, S.; Petrinca, P.; Petrov, Y.; Pichel, A.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pinto, T.; Pirronello, V.; Pisanti, O.; Platino, M.; Pochon, J.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Redondo, A.; Reucroft, S.; Revenu, B.; Rezende, F. A. S.; Ridky, J.; Riggi, S.; Risse, M.; Rivière, C.; Rizi, V.; Roberts, M.; Robledo, C.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Roth, M.; Rouillé-D'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scherini, V.; Schieler, H.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schovánek, P.; Schüssler, F.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; Sigl, G.; de Grande, N. Smetniansky; Smiałkowski, A.; Šmída, R.; Smith, A. G. K.; Smith, B. E.; Snow, G. R.; Sokolsky, P.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Takahashi, J.; Tamashiro, A.; Tamburro, A.; Taşcău, O.; Tcaciuc, R.; Thao, N. T.; Thomas, D.; Ticona, R.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Peixoto, C. J. Todero; Tomé, B.; Tonachini, A.; Torres, I.; Travnicek, P.; Tripathi, A.; Tristram, G.; Tscherniakhovski, D.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Galicia, J. F. Valdés; Valiño, I.; Valore, L.; van den Berg, A. M.; van Elewyck, V.; Vázquez, R. A.; Veberič, D.; Veiga, A.; Velarde, A.; Venters, T.; Verzi, V.; Videla, M.; Villaseñor, L.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wainberg, O.; Warner, D.; Watson, A. A.; Westerhoff, S.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Wileman, C.; Winnick, M. G.; Wu, H.; Wundheiler, B.; Yamamoto, T.; Younk, P.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zech, A.; Zepeda, A.; Ziolkowski, M.

    2008-04-01

    Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than ˜6 × 1019 eV and AGN at a distance less than ˜75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest-energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen Zatsepin Kuz’min effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory.

  9. Lower Bound on the Cosmic TeV Gamma-ray Background Radiation

    CERN Document Server

    Inoue, Yoshiyuki

    2015-01-01

    The Fermi gamma-ray space telescope has revolutionized our understanding of the cosmic gamma-ray background radiation in the GeV band. However, investigation on the cosmic TeV gamma-ray background radiation still remains sparse. Here, we report the lower bound on the cosmic TeV gamma-ray background spectrum placed by the cumulative flux of individual detected extragalactic TeV sources including blazars, radio galaxies, and starburst galaxies. The current limit on the cosmic TeV gamma-ray background above 0.1 TeV is obtained as $3\\times10^{-8} (E/100~{\\rm GeV})^{-0.6} \\exp(-E/2000~{\\rm GeV})~{\\rm [GeV/cm^2/s/sr]} < E^2dN/dE < 1\\times10^{-7} (E/100~{\\rm GeV})^{-0.5}~{\\rm [GeV/cm^2/s/sr]}$, where the upper bound is set by requirement that the cascade flux from the cosmic TeV gamma-ray background radiation can not exceed the measured cosmic GeV gamma-ray background spectrum (Inoue & Ioka 2012). Two nearby blazars, Mrk 421 and Mrk 501, explain ~70% of the cumulative flux at 0.8-4 TeV, while extreme blaza...

  10. Are gamma-ray bursts the sources of ultra-high energy cosmic rays?

    CERN Document Server

    Baerwald, Philipp; Winter, Walter

    2014-01-01

    We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the information from gamma-rays, cosmic rays, prompt neutrinos, and cosmogenic neutrinos quantitatively in a joint cosmic ray production and propagation model, and we show that the information on the cosmic energy budget can be obtained as a consequence. In addition to the neutron model, we consider alternative scenarios for the cosmic ray escape from the GRBs, i.e., that cosmic rays can leak from the sources. We find that the dip model, which describes the ankle in UHECR observations by the pair production dip, is strongly disfavored in combination with the internal shock model because a) unrealistically high baryonic loadings (energy in protons versus energy in electrons/gamma-rays) are needed for the individual GRBs and b) the prompt neutrino flux easily overshoots the corres...

  11. Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration, The Pierre auger

    2007-12-01

    Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [1]. The correlation has maximum significance for cosmic rays with energy greater than {approx} 6 x 10{sup 19} eV and AGN at a distance less than {approx} 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen-Zatsepin-Kuzmin effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory.

  12. On the slow time geomagnetic field modulation of galactic cosmic rays

    Science.gov (United States)

    Okpala, Kingsley

    2016-07-01

    Cosmic rays of galactic origin are modulated by both heliospheric and geomagnetic conditions. The mutual (and mutually exclusive) contribution of both heliospheric and geomagnetic conditions to galactic cosmic rays (GCR) modulation is still an open question. While the rapid-time association of the galactic cosmic ray variation with different heliophysical and geophysical phenomena has been well studied, not so much attention has been paid to slow-time variations especially with regards to local effects. In this work, we employed monthly means of cosmic ray count rates from two mid latitude (Hermanus and Rome), and two higher latitude (Inuvik and Oulu) neutron monitors (NM), and compared their variability with geomagnetic stations that are in close proximity to the NMs. The data spans 1966 to 2008 and covers four (4) solar cycles. The difference (DeltaCR)between the mean count rate of all days and the mean of the five quietest days for each month was compared with the Dst-related disturbance (DeltaH) derived from the nearby geomagnetic stations. Zeroth- and First- correlation between the cosmic ray parameters and geomagnetic parameters was performed to ascertain statistical association and test for spurious association. Our results show that solar activity is generally strongly correlated (>0.75) with mean strength of GCR count rate and geomagnetic field during individual solar cycles. The correlation between mean strength of cosmic ray intensity and Geomagnetic field strength is spurious and is basically moderated by the solar activity. The signature of convection driven disturbances at high latitude geomagnetic stations was evident during the declining phase of the solar cycles close to the solar minimum. The absence of this feature in the slow-time varying cosmic ray count rates in all stations, and especially in the mid latitude geomagnetic stations suggest that the local geomagnetic disturbance contributes much less in modulating the cosmic ray flux.

  13. Space Weather Observations by GNSS Radio Occultation: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2

    Science.gov (United States)

    Yue, Xinan; Schreiner, William S; Pedatella, Nicholas; Anthes, Richard A; Mannucci, Anthony J; Straus, Paul R; Liu, Jann-Yenq

    2014-01-01

    The joint Taiwan-United States FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission, hereafter called COSMIC, is the first satellite constellation dedicated to remotely sense Earth's atmosphere and ionosphere using a technique called Global Positioning System (GPS) radio occultation (RO). The occultations yield abundant information about neutral atmospheric temperature and moisture as well as space weather estimates of slant total electron content, electron density profiles, and an amplitude scintillation index, S4. With the success of COSMIC, the United States and Taiwan are moving forward with a follow-on RO mission named FORMOSAT-7/COSMIC-2 (COSMIC-2), which will ultimately place 12 satellites in orbit with two launches in 2016 and 2019. COSMIC-2 satellites will carry an advanced Global Navigation Satellite System (GNSS) RO receiver that will track both GPS and Russian Global Navigation Satellite System signals, with capability for eventually tracking other GNSS signals from the Chinese BeiDou and European Galileo system, as well as secondary space weather payloads to measure low-latitude plasma drifts and scintillation at multiple frequencies. COSMIC-2 will provide 4–6 times (10–15X in the low latitudes) the number of atmospheric and ionospheric observations that were tracked with COSMIC and will also improve the quality of the observations. In this article we focus on COSMIC/COSMIC-2 measurements of key ionospheric parameters. PMID:26213514

  14. The life and death of cosmic voids

    CERN Document Server

    Sutter, P M; Falck, Bridget; Onions, Julian; Hamaus, Nico; Knebe, Alexander; Srisawat, Chaichalit; Schneider, Aurel

    2014-01-01

    We investigate the formation, growth, merger history, movement, and destruction of cosmic voids detected via the watershed transform in a cosmological N-body dark matter {\\Lambda}CDM simulation. By adapting a method used to construct halo merger trees, we are able to trace individual voids back to their initial appearance and record the merging and evolution of their progenitors at high redshift. For the scales of void sizes captured in our simulation, we find that the void formation rate peaks at scale factor 0.3, which coincides with a growth in the void hierarchy and the emergence of dark energy. Voids of all sizes appear at all scale factors, though the median initial void size decreases with time. When voids become detectable they have nearly their present-day volumes. Almost all voids have relatively stable growth rates and suffer only infrequent minor mergers. Dissolution of a void via merging is very rare. Instead, most voids maintain their distinct identity as annexed subvoids of a larger parent. The...

  15. Cosmic-ray propagation in molecular clouds

    CERN Document Server

    Padovani, Marco

    2013-01-01

    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 about 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 3-4 depending on the position inside the core and the magnetisation of the core.

  16. Cosmic ray transport in astrophysical plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- & Astrophysik, Ruhr-Universität, Bochum (Germany)

    2015-09-15

    Since the development of satellite space technology about 50 years ago the solar heliosphere is explored almost routinely by several spacecrafts carrying detectors for measuring the properties of the interplanetary medium including energetic charged particles (cosmic rays), solar wind particle densities, and electromagnetic fields. In 2012, the Voyager 1 spacecraft has even left what could be described as the heliospheric modulation region, as indicated by the sudden disappearance of low energy heliospheric cosmic ray particles. With the available in-situ measurements of interplanetary turbulent electromagnetic fields and of the momentum spectra of different cosmic ray species in different interplanetary environments, the heliosphere is the best cosmic laboratory to test our understanding of the transport and acceleration of cosmic rays in space plasmas. I review both the historical development and the current state of various cosmic ray transport equations. Similarities and differences to transport theories for terrestrial fusion plasmas are highlighted. Any progress in cosmic ray transport requires a detailed understanding of the electromagnetic turbulence that is responsible for the scattering and acceleration of these particles.

  17. Observational Probes of Cosmic Acceleration

    CERN Document Server

    Weinberg, David H; Eisenstein, Daniel J; Hirata, Christopher; Riess, Adam G; Rozo, Eduardo

    2012-01-01

    The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious experimental efforts to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski test, and direct meas...

  18. Polarization of Cosmic Microwave Background

    CERN Document Server

    Buzzelli, Alessandro; de Gasperis, Giancarlo; Vittorio, Nicola

    2016-01-01

    In this work we present an extension of the ROMA map-making code for data analysis of Cosmic Microwave Background polarization, with particular attention given to the inflationary polarization B-modes. The new algorithm takes into account a possible cross-correlated noise component among the different detectors of a CMB experiment. We tested the code on the observational data of the BOOMERanG (2003) experiment and we show that we are provided with a better estimate of the power spectra, in particular the error bars of the BB spectrum are smaller up to 20% for low multipoles. We point out the general validity of the new method. A possible future application is the LSPE balloon experiment, devoted to the observation of polarization at large angular scales.

  19. Reconnection of Colliding Cosmic Strings

    CERN Document Server

    Hanany, A; Hanany, Amihay; Hashimoto, Koji

    2005-01-01

    For vortex strings in the Abelian Higgs model and D-strings in superstring theory, both of which can be regarded as cosmic strings, we give analytical study of reconnection (recombination, inter-commutation) when they collide, by using effective field theories on the strings. First, for the vortex strings, via a string sigma model, we verify analytically that the reconnection is classically inevitable for small collision velocity and small relative angle. Evolution of the shape of the reconnected strings provides an upper bound on the collision velocity in order for the reconnection to occur. These analytical results are in agreement with previous numerical results. On the other hand, reconnection of the D-strings is not classical but probabilistic. We show that a quantum calculation of the reconnection probability using a D-string action reproduces the nonperturbative nature of the worldsheet results by Jackson, Jones and Polchinski. The difference on the reconnection -- classically inevitable for the vortex...

  20. Cosmic backreaction and Gauss's law

    CERN Document Server

    Fleury, Pierre

    2016-01-01

    Cosmic backreaction refers to the general question of whether a homogeneous and isotropic cosmological model is able to predict the correct expansion dynamics of our inhomogeneous Universe. One aspect of this issue concerns the validity of the continuous approximation: does a system of point masses expand the same way as a fluid does? This article shows that it is not exactly the case in Newtonian gravity, although the associated corrections vanish in an infinite Universe. It turns out that Gauss's law is a key ingredient for such corrections to vanish. Backreaction therefore generically arises in alternative theories of gravitation, which threatens the trustworthiness of their cosmological tests. This phenomenon is illustrated with a toy-model of massive gravity.

  1. Cosmic backreaction and Gauss's law

    Science.gov (United States)

    Fleury, Pierre

    2017-06-01

    Cosmic backreaction refers to the general question of whether a homogeneous and isotropic cosmological model is able to predict the correct expansion dynamics of our inhomogeneous Universe. One aspect of this issue concerns the validity of the continuous approximation: does a system of point masses expand the same way as a fluid does? This article shows that it is not exactly the case in Newtonian gravity, although the associated corrections vanish in an infinite Universe. It turns out that Gauss's law is a key ingredient for such corrections to vanish. Backreaction, therefore, generically arises in alternative theories of gravitation, which threatens the trustworthiness of their cosmological tests. This phenomenon is illustrated with a toy model of massive gravity.

  2. Protostars: forge of cosmic rays?

    CERN Document Server

    Padovani, M; Hennebelle, P; Ferrière, K

    2016-01-01

    Galactic cosmic rays (CR) are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy as well as their ionisation efficiency because of the presence of magnetic fields and collisions with molecular hydrogen. Recent observations hint at high levels of ionisation and to the presence of synchrotron emission in protostellar systems, therefore leading to an apparent contradiction. We want to explain the origin of these CRs accelerated within young protostars as suggested by observations. Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient CR acceleration through diffusive shock acceleration. We analyse three main acceleration sites, then we follow the propagation of these particles through the protostellar system up to the hot spot region. We find that jet shocks can be strong accelerators of CR protons, which can be boosted up to relativistic energies. Another ...

  3. Cosmic Convergence: Art and Science

    Science.gov (United States)

    Mayo, Elizabeth A.; Zisholtz, E.; Hilton, H.

    2010-01-01

    The I.P. Stanback Museum and Planetarium is a major educational and teaching resource for South Carolina State University, K-12 schools, other universities and the community of Orangeburg and well beyond. The concept of creating a museum with a planetarium on the campus of SC State was ahead of its time. Today scholars are writing about the unity of creative disciplines. Through its integration of the arts, humanities and sciences, the Stanback, the only art museum with a planetarium at any of the Historically Black Colleges and Universities and one of the few in the nation, stands in the forefront of modern thinking. Cosmic Convergence: Art and Science, opening at the I.P. Stanback Museum and Planetarium in February 2010, will feature the works of Mildred Thompson (1936-2003), a prominent African American artist who worked in the media of painting, drawing, print making, sculpture, and photography. Thompson’s artwork shows the strong influences of her interest in physics, astronomy, and metaphysics as well as music and spiritualism. “My work in the visual arts is, and has always been, a continuous search for understanding. It is an expression of purpose and reflects a personal interpretation of the Universe.” Cosmic Convergence will explore the meeting of Art and Science through Mildred Thompson's work and the scientific basis of that work. The paintings and sculptures of the exhibit will be combined with astronomical images showing both the reality and interpretation of the surrounding Universe. Support for this work was provided by the NSF PAARE program to South Carolina State University under award AST-0750814.

  4. Symbols of a cosmic order

    Science.gov (United States)

    Madjid, F. Hadi; Myers, John M.

    2016-10-01

    The world runs on networks over which signals communicate sequences of symbols, e.g. numerals. Examining both engineered and natural communications networks reveals an unsuspected order that depends on contact with an unpredictable entity. This order has three roots. The first is a proof within quantum theory that no evidence can ever determine its explanation, so that an agent choosing an explanation must do so unpredictably. The second root is the showing that clocks that step computers do not "tell time" but serve as self-adjusting symbol-handling agents that regulate "logically synchronized" motion in response to unpredictable disturbances. Such a clock-agent has a certain independence as well as the capacity to communicate via unpredictable symbols with other clock-agents and to adjust its own tick rate in response to that communication. The third root is the noticing of unpredictable symbol exchange in natural systems, including the transmission of symbols found in molecular biology. We introduce a symbol-handling agent as a role played in some cases by a person, for example a physicist who chooses an explanation of given experimental outcomes, and in other cases by some other biological entity, and in still other cases by an inanimate device, such as a computer-based detector used in physical measurements. While we forbear to try to explain the propensity of agents at all levels from cells to civilizations to form and operate networks of logically synchronized symbol-handling agents, we point to this propensity as an overlooked cosmic order, an order structured by the unpredictability ensuing from the proof. Appreciating the cosmic order leads to a conception of agency that replaces volition by unpredictability and reconceives the notion of objectivity in a way that makes a place for agency in the world as described by physics. Some specific implications for physics are outlined.

  5. A Simplified Model for the Acceleration of Cosmic Ray Particles

    Science.gov (United States)

    Gron, Oyvind

    2010-01-01

    Two important questions concerning cosmic rays are: Why are electrons in the cosmic rays less efficiently accelerated than nuclei? How are particles accelerated to great energies in ultra-high energy cosmic rays? In order to answer these questions we construct a simple model of the acceleration of a charged particle in the cosmic ray. It is not…

  6. Cosmic chronometers in the Rh = ct Universe

    Science.gov (United States)

    Melia, Fulvio; Maier, Robert S.

    2013-07-01

    The use of luminous red galaxies as cosmic chronometers provides us with an indispensable method of measuring the universal expansion rate H(z) in a model-independent way. Unlike many probes of the cosmological history, this approach does not rely on integrated quantities, such as the luminosity distance, and therefore does not require the pre-assumption of any particular model, which may bias subsequent interpretations of the data. We employ three statistical tools - the Akaike, Kullback and Bayes Information Criteria (AIC, KIC and BIC) - to compare the Λ cold dark matter (ΛCDM) model and the Rh = ct Universe with the currently available measurements of H(z), and show that the Rh = ct Universe is favoured by these model selection criteria. The parameters in each model are individually optimized by maximum likelihood estimation. The Rh = ct Universe fits the data with a reduced χ2dof=0.745 for a Hubble constant H0 = 63.2 ± 1.6 km s-1 Mpc-1, and H0 is the sole parameter in this model. By comparison, the optimal ΛCDM model, which has three free parameters (including H0 = 68.9 ± 3.3 km s-1 Mpc-1, Ωm = 0.32, and a dark-energy equation of state pde = -ρde), fits the H(z) data with a reduced χ2dof = 0.777. With these χ2dof values, the AIC yields a likelihood of ≈82 per cent that the distance-redshift relation of the Rh = ct Universe is closer to the correct cosmology, than is the case for ΛCDM. If the alternative BIC criterion is used, the respective Bayesian posterior probabilities are 91.2 per cent (Rh = ct) versus 8.8 per cent (ΛCDM). Using the concordance ΛCDM parameter values, rather than those obtained by fitting ΛCDM to the cosmic chronometer data, would further disfavour ΛCDM.

  7. Anisotropy and Corotation of Galactic Cosmic Rays

    Institute of Scientific and Technical Information of China (English)

    The Chinese collaboration team at YangBaJing Cosmi

    2007-01-01

    @@ Based on some 40 billion cosmic ray events collected from 1997 to 2005 by the Tibet Air Shower Array experiment (a major scientific collaboration between China and Japan) operating at the YangBaJing Cosmic Ray Observatory (90.522 E, 30. 102 N; 4300 m above sea level) near Lhasa in Tibet, a two-dimensiondl cosmic-ray intensity map in the sky was obtained with very high directional granularity and unprecedented precision in intensity at a level of 10-4.

  8. The cosmic $e^\\pm$ anomaly

    OpenAIRE

    Auchettl, Katie; Balazs, Csaba

    2013-01-01

    Via a Bayesian likelihood analysis using 219 recent cosmic ray spectral data points we extract the anomalous part of the cosmic $e^\\pm$ flux. First we show that a significant tension exists between the $e^\\pm$ related and the rest of the fluxes. Interpreting this tension as the presence of an anomalous component in the $e^\\pm$ related data, we then infer the values of selected cosmic ray propagation parameters excluding the anomalous data sample from the analysis. Based on these values we cal...

  9. Gravitational phase operator and cosmic strings

    CERN Document Server

    Anandan, Jeeva S

    1996-01-01

    A quantum equivalence principle is formulated by means of a gravitational phase operator which is an element of the Poincare group. This is applied to the spinning cosmic string which suggests that it may contain gravitational torsion. A new exact solution of the Einstein- Cartan-Sciama-Kibble equations for the gravitational field with torsion is obtained everywhere for a cosmic string with uniform energy density, spin density and flux. A novel effect due to the quantized gravitational field of the cosmic string on the wave function of a particle outside the string is used to show that spacetime points are not meaningful in quantum gravity.

  10. High-energy cosmic-ray acceleration

    CERN Document Server

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  11. Radiation from cosmic string standing waves

    Science.gov (United States)

    Olum; Blanco-Pillado

    2000-05-01

    We have simulated large-amplitude standing waves on an Abelian-Higgs cosmic string in classical lattice field theory. The radiation rate falls exponentially with wavelength, as one would expect from the field profile around a gauge string. Our results agree with those of Moore and Shellard, but not with those of Vincent, Antunes, and Hindmarsh. The radiation rate falls too rapidly to sustain a scaling solution via direct radiation of particles from string length. There is thus reason to doubt claims of strong constraints on cosmic string theories from cosmic ray observations.

  12. Cosmic Muon Detector Using Proportional Chambers

    CERN Document Server

    Varga, Dezső; Hamar, Gergő; Molnár, Janka Sára; Oláh, Éva; Pázmándi, Péter

    2015-01-01

    A set of classical multi-wire proportional chambers were designed and constructed with the main purpose of efficient cosmic muon detection. These detectors are relatively simple to construct, and at the same time are low cost, making them ideal for educational purposes. The detector layers have efficiencies above 99% for minimum ionizing cosmic muons, and their position resolution is about 1 cm, that is, particle trajectories are clearly observable. Visualization of straight tracks is possible using an LED array, with the discriminated and latched signal driving the display. Due to the exceptional operating stability of the chambers, the design can also be used for cosmic muon telescopes.

  13. Cosmic radiation during air travel: trends in exposure of aircrews and airline passengers

    NARCIS (Netherlands)

    Blaauboer RO; LSO

    2004-01-01

    An unfavourable effect of flying is the enhanced exposure of both passengers and aircrew to cosmic radiation at high altitudes. On the basis of a detailed survey on passengers arriving at or departing from Amsterdam Schiphol Airport in the 1988-1997 period, estimates of individual effective dose for

  14. Cosmocultural Evolution: Cosmic Motivation for Interstellar Travel?

    Science.gov (United States)

    Lupisella, M.

    Motivations for interstellar travel can vary widely from practical survival motivations to wider-ranging moral obligations to future generations. But it may also be fruitful to explore what, if any, "cosmic" relevance there may be regarding interstellar travel. Cosmocultural evolution can be defined as the coevolution of cosmos and culture, with cultural evolution playing an important and perhaps critical role in the overall evolution of the universe. Strong versions of cosmocultural evolution might suggest that cultural evolution may have unlimited potential as a cosmic force. In such a worldview, the advancement of cultural beings throughout the universe could have significant cosmic relevance, perhaps providing additional motivation for interstellar travel. This paper will explore some potential philosophical and policy implications for interstellar travel of a cosmocultural evolutionary perspective and other related concepts, including some from a recent NASA book, Cosmos and Culture: Cultural Evolution in a Cosmic Context.

  15. Bayesian Cosmic Web Reconstruction: BARCODE for Clusters

    CERN Document Server

    Bos, E G Patrick; Kitaura, Francisco; Cautun, Marius

    2016-01-01

    We describe the Bayesian BARCODE formalism that has been designed towards the reconstruction of the Cosmic Web in a given volume on the basis of the sampled galaxy cluster distribution. Based on the realization that the massive compact clusters are responsible for the major share of the large scale tidal force field shaping the anisotropic and in particular filamentary features in the Cosmic Web. Given the nonlinearity of the constraints imposed by the cluster configurations, we resort to a state-of-the-art constrained reconstruction technique to find a proper statistically sampled realization of the original initial density and velocity field in the same cosmic region. Ultimately, the subsequent gravitational evolution of these initial conditions towards the implied Cosmic Web configuration can be followed on the basis of a proper analytical model or an N-body computer simulation. The BARCODE formalism includes an implicit treatment for redshift space distortions. This enables a direct reconstruction on the ...

  16. Some Aspects of Galactic Cosmic Ray Acceleration

    CERN Document Server

    Butt, Y M

    2003-01-01

    I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation.

  17. Smooth halos in the cosmic web

    CERN Document Server

    Gaite, Jose

    2014-01-01

    Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of equality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in $N$-body simulations. These entropic measures provide us with a quantitative description of the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these "smoothness sizes" have no direct relation to the virial radii.

  18. Comparing cosmic web classifiers using information theory

    CERN Document Server

    Leclercq, Florent; Jasche, Jens; Wandelt, Benjamin

    2016-01-01

    We introduce a decision scheme for optimally choosing a classifier, which segments the cosmic web into different structure types (voids, sheets, filaments, and clusters). Our framework, based on information theory, accounts for the design aims of different classes of possible applications: (i) parameter inference, (ii) model selection, and (iii) prediction of new observations. As an illustration, we use cosmographic maps of web-types in the Sloan Digital Sky Survey to assess the relative performance of the classifiers T-web, DIVA and ORIGAMI for: (i) analyzing the morphology of the cosmic web, (ii) discriminating dark energy models, and (iii) predicting galaxy colors. Our study substantiates a data-supported connection between cosmic web analysis and information theory, and paves the path towards principled design of analysis procedures for the next generation of galaxy surveys. We have made the cosmic web maps, galaxy catalog, and analysis scripts used in this work publicly available.

  19. Effects of Cosmic Strings on Free Streaming

    CERN Document Server

    Takahashi, T; Takahashi, Tomo; Yamaguchi, Masahide

    2006-01-01

    We study the effect of free streaming in a universe with cosmic strings with time-varying tension as well as with constant tension. Although current cosmological observations suggest that fluctuation seeded by cosmic strings cannot be the primary source of cosmic density fluctuation, some contributions from them are still allowed. Since cosmic strings actively produce isocurvature fluctuation, the damping of small scale structure via free streaming by dark matter particles with large velocity dispersion at the epoch of radiation-matter equality is less efficient than that in models with conventional adiabatic fluctuation. We discuss its implications to the constraints on the properties of particles such as massive neutrinos and warm dark matter.

  20. Comparing cosmic web classifiers using information theory

    Science.gov (United States)

    Leclercq, Florent; Lavaux, Guilhem; Jasche, Jens; Wandelt, Benjamin

    2016-08-01

    We introduce a decision scheme for optimally choosing a classifier, which segments the cosmic web into different structure types (voids, sheets, filaments, and clusters). Our framework, based on information theory, accounts for the design aims of different classes of possible applications: (i) parameter inference, (ii) model selection, and (iii) prediction of new observations. As an illustration, we use cosmographic maps of web-types in the Sloan Digital Sky Survey to assess the relative performance of the classifiers T-WEB, DIVA and ORIGAMI for: (i) analyzing the morphology of the cosmic web, (ii) discriminating dark energy models, and (iii) predicting galaxy colors. Our study substantiates a data-supported connection between cosmic web analysis and information theory, and paves the path towards principled design of analysis procedures for the next generation of galaxy surveys. We have made the cosmic web maps, galaxy catalog, and analysis scripts used in this work publicly available.

  1. Cosmic Voids: structure, dynamics and galaxies

    CERN Document Server

    van de Weygaert, Rien

    2009-01-01

    In this review we discuss several aspects of Cosmic Voids. Voids are a major component of the large scale distribution of matter and galaxies in the Universe. They are of instrumental importance for understanding the emergence of the Cosmic Web. Their relatively simple shape and structure makes them into useful tools for extracting the value of a variety cosmic parameters, possibly including even that of the influence of dark energy. Perhaps most promising and challenging is the issue of the galaxies found within their realm. Not only does the pristine environment of voids provide a promising testing ground for assessing the role of environment on the formation and evolution of galaxies, the dearth of dwarf galaxies may even represent a serious challenge to the standard view of cosmic structure formation.

  2. Development of the cosmic ray techniques

    Science.gov (United States)

    Rossi, B.

    1982-12-01

    It has been found that most advances of cosmic-ray physics have been directly related to the development of observational techniques. The history of observational techniques is discussed, taking into account ionization chambers, refinements applied to ionization chambers to make them suitable for an effective use in the study of cosmic radiation, the Wulf-type electrometer, the electrometer designed by Millikan and Neher, the Geiger-Mueller counter, the experiment of Bothe and Kolhoerster, the coincidence circuit, and a cosmic-ray 'telescope'. Attention is given to a magnetic lens for cosmic rays, a triangular arrangement of Geiger-Mueller counters used to demonstrate the production of a secondary radiation, a stereoscopic cloud-chamber photograph of showers, the cloud-chamber picture which provided the first evidence of the positive electron, and arrangements for studying photon components, mu-mesons, and air showers.

  3. Yakov Zeldovich and the Cosmic Web Paradigm

    CERN Document Server

    Einasto, Jaan

    2014-01-01

    I discuss the formation of the modern cosmological paradigm. In more detail I describe the early study of dark matter and cosmic web and the role of Yakov Zeldovich in the formation of the present concepts on these subjects.

  4. Yakov Zeldovich and the Cosmic Web Paradigm

    Science.gov (United States)

    Einasto, Jaan

    2016-10-01

    I discuss the formation of the modern cosmological paradigm. In more detail I describe the early study of dark matter and cosmic web and the role of Yakov Zeldovich in the formation of the present concepts on these subjects.

  5. Cosmic ray physics with ARGO-YBJ

    CERN Document Server

    ,

    2016-01-01

    The ARGO--YBJ experiment has been in stable data taking for more than five years at the Yangbajing cosmic ray observatory (Tibet, P.R. China, 4300 m a.s.l.). The detector collected about $5\\times10^{11}$ events in a wide energy range from few TeVs up to the PeV region. In this work we summarize the latest results in cosmic ray physics particularly focusing on the cosmic ray energy spectrum. The results of the measurement of the all-particle and proton plus helium energy spectra in the energy region between $10^{12} - 10^{16}$ eV are discussed. A precise measurement of the cosmic ray energy spectrum and composition in this energy region allows a better understanding of the origin of the knee and provides a powerful cross-check among different experimental techniques.

  6. Occupational cosmic radiation exposure and cancer in airline cabin crew.

    Energy Technology Data Exchange (ETDEWEB)

    Kojo, K.

    2013-03-15

    Cosmic radiation dose rates are considerably higher at cruising altitudes of airplanes than at ground level. Previous studies have found increased risk of certain cancers among aircraft cabin crew, but the results are not consistent across different studies. Despite individual cosmic radiation exposure assessment is important for evaluating the relation between cosmic radiation exposure and cancer risk, only few previous studies have tried to develop an exposure assessment method. The evidence for adverse health effects in aircrews due to ionizing radiation is inconclusive because quantitative dose estimates have not been used. No information on possible confounders has been collected. For an occupational group with an increased risk of certain cancers it is very important to assess if the risk is related to occupational exposure. The goal of this thesis was to develop two separate retrospective exposure assessment methods for occupational exposure to cosmic radiation. The methods included the assessment based on survey on flight histories and based on company flight timetables. Another goal was to describe the cancer incidence among aircraft cabin crew with a large cohort in four Nordic countries, i.e., Finland, Iceland, Norway, and Sweden. Also the contribution of occupational as well as non-occupational factors to breast and skin cancer risk among the cabin crew was studied with case-control studies. Using the survey method of cosmic radiation exposure assessment, the median annual radiation dose of Finnish airline cabin crew was 0.6 milliSievert (mSv) in the 1960s, 3.3 mSv in the 1970s, and 3.6 mSv in the 1980s. With the flight timetable method, the annual radiation dose increased with time being 0.7 mSv in the 1960 and 2.1 mSv in the 1995. With the survey method, the median career dose was 27.9 mSv and with the timetable method 20.8 mSv. These methods provide improved means for individual cosmic radiation exposure assessment compared to studies where cruder

  7. Spectrum and anisotropy of cosmic rays at TeV-PeV-energies and contribution of nearby sources

    Science.gov (United States)

    Sveshnikova, L. G.; Strelnikova, O. N.; Ptuskin, V. S.

    2013-12-01

    The role of nearby galactic sources, the supernova remnants, in formation of observed energy spectrum and large-scale anisotropy of high-energy cosmic rays is studied. The list of these sources is made up based on radio, X-ray and gamma-ray catalogues. The distant sources are treated statistically as ensemble of sources with random positions and ages. The source spectra are defined based on the modern theory of cosmic ray acceleration in supernova remnants while the propagation of cosmic rays in the interstellar medium is described in the frameworks of galactic diffusion model. Calculations of dipole component of anisotropy are made to reproduce the experimental procedure of "two-dimensional" anisotropy measurements. The energy dependence of particle escape time in the process of acceleration in supernova remnants and the arm structure of sources defining the significant features of anisotropy are also taken into account. The essential new trait of the model is a decreasing number of core collapse SNRs being able to accelerate cosmic rays up to the given energy, that leads to steeper total cosmic ray source spectrum in comparison with the individual source spectrum. We explained simultaneously the new cosmic ray data on the fine structure of all particle spectrum around the knee and the amplitude and direction of the dipole component of anisotropy in the wide energy range 1 TeV-1 EeV. Suggested assumptions do not look exotic, and they confirm the modern understanding of cosmic ray origin.

  8. Implications of Cosmic Repulsion for Gravitational Theory

    CERN Document Server

    Mannheim, P D

    1998-01-01

    In this paper we present a general, model independent analysis of a recently detected apparent cosmic repulsion, and discuss its potential implications for gravitational theory. In particular, we show that a negatively spatially curved universe acts like a diverging refractive medium, to thus naturally cause galaxies to accelerate away from each other. Additionally, we show that it is possible for a cosmic acceleration to only be temporary, with some accelerating universes actually being able to subsequently recontract.

  9. Longevity and Highest-Energy Cosmic Rays

    CERN Document Server

    Frampton, Paul H; Ng, Y J; Frampton, Paul H.; Keszthelyi, Bettina

    1999-01-01

    It is proposed that the highest energy $\\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor which has propagated from typically $\\sim 100$Mpc. Such a scenario can occur in e.g. SU(15) grand unification and in some preon models, but is more generic; if true, these unusual cosmic rays provide a window into new physics.

  10. Statistics of Peculiar Velocities from Cosmic Strings

    OpenAIRE

    Moessner, R.

    1995-01-01

    We calculate the probability distribution of a single component of peculiar velocities due to cosmic strings, smoothed over regions with a radius of several $h^{-1}$ Mpc. The probability distribution is shown to be Gaussian to good accuracy, in agreement with the distribution of peculiar velocities deduced from the 1.9 Jy IRAS redshift survey. Using the normalization of parameters of the cosmic string model from CMB measurements, we show that the rms values for peculiar velocities inferred fr...

  11. Cosmic ray test of INO RPC stack

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, M. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Datar, V.M. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kalmani, S.D.; Lahamge, S.M.; Mondal, N.K.; Nagaraj, P.; Pal, S.; Reddy, L.V.; Redij, A.; Samuel, D.; Saraf, M.N. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Satyanarayana, B., E-mail: bsn@tifr.res.in [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Shinde, R.R.; Verma, P. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2012-01-01

    The India-based Neutrino Observatory (INO) collaboration is planning to build a 50 kt magnetised iron calorimeter (ICAL) detector using glass Resistive Plate Chambers (RPCs) as active detector elements. A stack of 12 such glass RPCs of 1 m Multiplication-Sign 1 m in area is tracking cosmic ray muons for over three years. In this paper, we will review the constructional aspects of the stack and discuss the performance of the RPCs using this cosmic ray data.

  12. The New Physics of Cosmic Redshift

    CERN Document Server

    Hebel, Wolfgang

    2011-01-01

    Light rays received on earth from distant stars show redshift, being attributed conventionally to the well-known Doppler-effect of wave dynamics. The present study concludes that cosmic redshift rather is an effect of the quantum mechanical propagation of photons as explained by Nobel Laureate Richard FEYNMAN in his book on QED {2}. This alternative physics of cosmic redshift is fundamentally different from the conventional velocity argument and can therefore do without the controversial big bang idea.

  13. Galactic origin of ultrahigh energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, A.A. [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation)

    2009-05-15

    The arrival directions of ultrahigh energy extensive air showers (EAS) by Yakutsk, AGASA, P. Auger array data are analyzed. For the first time, the maps of equal exposition of celestial sphere for the distribution of particles by AGASA and P. Auger arrays data have been constructed. The large-scale anisotropy of cosmic particles at E>4x10{sup 19} eV by Yakutsk, AGASA and P. Auger array data has been detected. The problem of cosmic particle origin is discussed.

  14. Are there strangelets in cosmic rays?

    CERN Document Server

    Rybczynski, M; Wilk, G

    2004-01-01

    Assuming that cosmic rays entering the Earth's atmosphere contain a small admixture of nuggets of strange quark matter in form of strangelets one can explain a number of apparently "strange" effects observed in different cosmic rays experiments. We shall demonstrate here that the mass spectrum of such strangelets filles the "nuclear desert" gap existing between the heaviest elements observed in Universe and the next "nuclear-like objects" represented by neutron and strange stars.

  15. CMB distortions from superconducting cosmic strings

    Science.gov (United States)

    Tashiro, Hiroyuki; Sabancilar, Eray; Vachaspati, Tanmay

    2012-05-01

    We reconsider the effect of electromagnetic radiation from superconducting strings on cosmic microwave background μ and y distortions and derive present (COBE-FIRAS) and future (PIXIE) constraints on the string tension, μs, and electric current, I. We show that absence of distortions of the cosmic microwave background in PIXIE will impose strong constraints on μs and I, leaving the possibility of light strings (Gμs≲10-18) or relatively weak currents (I≲10TeV).

  16. Tracks of cosmic rays in plastics.

    Science.gov (United States)

    Fleischer, R L; Price, P B; Walker, R M; Filz, R C; Fukui, K; Friedlander, M W; Holeman, E; Rajan, R S; Tamhane, A S

    1967-01-13

    Cosmic ray nuclei have been observed with the use of plastic trackdetecting solids in satellites and high-altitude balloon flights. Nuclear emulsions in the stacks of plastic sheets allowed the positive identification of cosmic raynuclei as light as nitrogen. The most striking new information was the failure to observe relativistic iron nuclei, a result which has led to an advance in the understanding of track registration criteria.

  17. Cosmic Ray Interaction Models: an Overview

    Directory of Open Access Journals (Sweden)

    Ostapchenko Sergey

    2016-01-01

    Full Text Available I review the state-of-the-art concerning the treatment of high energy cosmic ray interactions in the atmosphere, discussing in some detail the underlying physical concepts and the possibilities to constrain the latter by current and future measurements at the Large Hadron Collider. The relation of basic characteristics of hadronic interactions tothe properties of nuclear-electromagnetic cascades induced by primary cosmic rays in the atmosphere is addressed.

  18. Critical decisions on Cosmic Vision

    Science.gov (United States)

    2003-11-01

    Eddington had two aims, both remarkable and very pertinent to front-line astronomical interests. The first was to look for Earth-like planets outside our solar system - one of the key goals in the search to understand how life came to be, how it is that we live where we do in the universe and whether there are other potential life-supporting environments 'out there'. At the same time it was going to follow the path that the ESA-NASA mission SOHO had taken with the Sun of using astroseismology to look 'inside' stars. In the longer term, the loss of this one mission will not stop ESA and the scientific community pursuing the grand quests to which it would have contributed. The loss of the BepiColombo lander is also hard to take scientifically. ESA, in conjunction with the Japanese space agency, JAXA, will still put two orbiters around Mercury but the ‘ground truth’ provided by the lander is a big loss. However, to land on a planet so near the Sun is no small matter and was a bridge too far in present circumstances, and this chance for Europe to be first has probably been lost. The origins of the problems were recognised at the ESA Council meeting held in June. Several sudden demands on finance occurred in the spring, the most obvious and public being the unforeseen Ariane 5 grounding in January, delaying the launches of Rosetta and Smart-1. A temporary loan of EUR 100 million was granted, but must be paid back out of present resources by the end of 2006. ESA's SPC was therefore caught in a vice. Immediate mission starts had to be severely limited and the overall envelope of the programme contained. With this week’s decisions, the SPC has brought the scope of the Cosmic Vision programme down to a level that necessarily reflects the financial conditions rather than the ambitions of the scientific community. A long and painful discussion during the SPC meeting resulted in the conclusion that only one new mission can be started at this time, namely LISA Pathfinder

  19. Recent developments in cosmic ray physics

    Energy Technology Data Exchange (ETDEWEB)

    Blasi, P. [INAF/Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5 50125 Firenze (Italy); Gran Sasso Science Institute (INFN), Viale F. Crispi 6, 60100 L' Aquila (Italy)

    2014-11-15

    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.

  20. Spaced-based Cosmic Ray Astrophysics

    Science.gov (United States)

    Seo, Eun-Suk

    2016-03-01

    The bulk of cosmic ray data has been obtained with great success by balloon-borne instruments, particularly with NASA's long duration flights over Antarctica. More recently, PAMELA on a Russian Satellite and AMS-02 on the International Space Station (ISS) started providing exciting measurements of particles and anti-particles with unprecedented precision upto TeV energies. In order to address open questions in cosmic ray astrophysics, future missions require spaceflight exposures for rare species, such as isotopes, ultra-heavy elements, and high (the ``knee'' and above) energies. Isotopic composition measurements up to about 10 GeV/nucleon that are critical for understanding interstellar propagation and origin of the elements are still to be accomplished. The cosmic ray composition in the knee (PeV) region holds a key to understanding the origin of cosmic rays. Just last year, the JAXA-led CALET ISS mission, and the DAMPE Chinese Satellite were launched. NASA's ISS-CREAM completed its final verification at GSFC, and was delivered to KSC to await launch on SpaceX. In addition, a EUSO-like mission for ultrahigh energy cosmic rays and an HNX-like mission for ultraheavy nuclei could accomplish a vision for a cosmic ray observatory in space. Strong support of NASA's Explorer Program category of payloads would be needed for completion of these missions over the next decade.

  1. Reminiscences of cosmic ray research in Mexico

    Science.gov (United States)

    Pérez-Peraza, Jorge

    2009-11-01

    Cosmic ray research in Mexico dates from the early 1930s with the work of the pioneering physicist, Manuel Sandoval Vallarta and his students from Mexico. Several experiments of international significance were carried out during that period in Mexico: they dealt with the geomagnetic latitude effect, the north-south and west-east asymmetry of cosmic ray intensity, and the sign of the charge of cosmic rays. The international cosmic ray community has met twice in Mexico for the International Cosmic Ray Conferences (ICRC): the fourth was held in Guanajuato in 1955, and the 30th took place in Mérida, in 2007. In addition, an international meeting on the Pierre Auger Collaboration was held in Morelia in 1999, and the International Workshop on Observing UHE Cosmic Rays took place in Metepec in 2000. A wide range of research topics has been developed, from low-energy Solar Energetic Particles (SEP) to the UHE. Instrumentation has evolved since the early 1950s, from a Simpson type neutron monitor installed in Mexico City (2300 m asl) to a solar neutron telescope and an EAS Cherenkov array, (within the framework of the Auger International Collaboration), both at present operating on Mt. Sierra La Negra in the state of Puebla (4580 m asl). Research collaboration has been undertaken with many countries; in particular, the long-term collaboration with Russian scientists has been very fruitful.

  2. Cosmic ray penetration in diffuse clouds

    CERN Document Server

    Morlino, G; Krause, J

    2015-01-01

    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 (ISM) 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 ISM if the latter is a power law $\\propto p^{-s}$ with $s$ larger (smaller) than $\\sim0.42$. As a consequence also the ionization rate due to CRs is strongly affected. Assuming an average Galactic spectrum similar to the one infe...

  3. Cosmic Visions Dark Energy: Science

    CERN Document Server

    Dodelson, Scott; Hirata, Chris; Honscheid, Klaus; Roodman, Aaron; Seljak, Uroš; Slosar, Anže; Trodden, Mark

    2016-01-01

    Cosmic surveys provide crucial information about high energy physics including strong evidence for dark energy, dark matter, and inflation. Ongoing and upcoming surveys will start to identify the underlying physics of these new phenomena, including tight constraints on the equation of state of dark energy, the viability of modified gravity, the existence of extra light species, the masses of the neutrinos, and the potential of the field that drove inflation. Even after the Stage IV experiments, DESI and LSST, complete their surveys, there will still be much information left in the sky. This additional information will enable us to understand the physics underlying the dark universe at an even deeper level and, in case Stage IV surveys find hints for physics beyond the current Standard Model of Cosmology, to revolutionize our current view of the universe. There are many ideas for how best to supplement and aid DESI and LSST in order to access some of this remaining information and how surveys beyond Stage IV c...

  4. Supersymmetry as a cosmic censor

    CERN Document Server

    Kallosh, Renata E; Ortín, Tomas; Peet, A W; Van Proeyen, A; Kallosh, Renata; Linde, Andrei; Ort\\'in, Tom\\'as; Peet, Amanda; Proeyen, Antoine Van

    1992-01-01

    In supersymmetric theories the mass of any state is bounded below by the values of some of its charges. The corresponding bounds in case of Schwarzschild and Reissner-Nordstr\\"om black holes are known to coincide with the requirement that naked singularities be absent. Here we investigate charged dilaton black holes in this context. We show that the extreme solutions saturate the supersymmetry bound of $N=4\\ d=4$ supergravity, or dimensionally reduced superstring theory. Specifically, we have shown that extreme dilaton black holes, with electric and magnetic charges, admit super-covariantly constant spinors. The supersymmetric positivity bound for dilaton black holes, $M \\geq \\frac{1}{\\sqrt 2}(|Q|+|P|)$, takes care of the absence of naked singularities of the dilaton black holes and is, in this sense, equivalent to the cosmic censorship condition. The temperature, entropy and singularity are discussed. The Euclidean action (entropy) of the extreme black hole is given by $2\\pi |PQ|$. We argue that this result,...

  5. Cosmic Visions Dark Energy. Science

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Heitmann, Katrin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Hirata, Chris [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Roodman, Aaron [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Seljak, Uroš [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Slosar, Anže [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Trodden, Mark [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-04-26

    Cosmic surveys provide crucial information about high energy physics including strong evidence for dark energy, dark matter, and inflation. Ongoing and upcoming surveys will start to identify the underlying physics of these new phenomena, including tight constraints on the equation of state of dark energy, the viability of modified gravity, the existence of extra light species, the masses of the neutrinos, and the potential of the field that drove inflation. Even after the Stage IV experiments, DESI and LSST, complete their surveys, there will still be much information left in the sky. This additional information will enable us to understand the physics underlying the dark universe at an even deeper level and, in case Stage IV surveys find hints for physics beyond the current Standard Model of Cosmology, to revolutionize our current view of the universe. There are many ideas for how best to supplement and aid DESI and LSST in order to access some of this remaining information and how surveys beyond Stage IV can fully exploit this regime. These ideas flow to potential projects that could start construction in the 2020's.

  6. Cosmic Visions Dark Energy: Science

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Slosar, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Heitmann, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hirata, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Honscheid, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roodman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Seljak, U. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trodden, M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-26

    Cosmic surveys provide crucial information about high energy physics including strong evidence for dark energy, dark matter, and inflation. Ongoing and upcoming surveys will start to identify the underlying physics of these new phenomena, including tight constraints on the equation of state of dark energy, the viability of modified gravity, the existence of extra light species, the masses of the neutrinos, and the potential of the field that drove inflation. Even after the Stage IV experiments, DESI and LSST, complete their surveys, there will still be much information left in the sky. This additional information will enable us to understand the physics underlying the dark universe at an even deeper level and, in case Stage IV surveys find hints for physics beyond the current Standard Model of Cosmology, to revolutionize our current view of the universe. There are many ideas for how best to supplement and aid DESI and LSST in order to access some of this remaining information and how surveys beyond Stage IV can fully exploit this regime. These ideas flow to potential projects that could start construction in the 2020's.

  7. Solar Modulation of Cosmic Rays

    CERN Document Server

    Potgieter, Marius

    2013-01-01

    This is an overview of the solar modulation of cosmic rays in the heliosphere. It is a broad topic with numerous intriguing aspects so that a research framework has to be chosen to concentrate on. The review focuses on the basic paradigms and departure points without presenting advanced theoretical or observational details for which there exists a large number of comprehensive reviews. Instead, emphasis is placed on numerical modeling which has played an increasingly signi?cant role as computational resources have become more abundant. A main theme is the progress that has been made over the years. The emphasis is on the global features of CR modulation and on the causes of the observed 11-year and 22-year cycles and charge-sign dependent modulation. Illustrative examples of some of the theoretical and observational milestones are presented, without attempting to review all details or every contribution made in this ?eld of research. Controversial aspects are discussed where appro- priate, with accompanying c...

  8. Quantum bounce and cosmic recall

    CERN Document Server

    Corichi, Alejandro

    2007-01-01

    Loop quantum cosmology predicts that, in simple models, the big bang singularity of classical general relativity is replaced by a quantum bounce. Because of the extreme physical conditions near the bounce, a natural question is whether the universe can retain, after the bounce, its memory about the previous epoch. More precisely, does the universe recall various properties of the state after evolving unitarily through the bounce or does it suffer from cosmic amnesia as has been recently suggested? Here we show that this issue can be answered unambiguously by means of an exactly solvable model, derived from a small simplification of loop quantum cosmology, for which there is full analytical control on the quantum theory. We show that if there exists a semi-classical state at late times on one side, peaked around a pair of canonically conjugate variables, then there are very strong bounds on the fluctuations on the other side of the bounce, implying semi-classicality. For a model universe which grows to a size ...

  9. Secondary cosmic ray nuclei in the light of the Single Source Model

    CERN Document Server

    Erlykin, Anatoly

    2016-01-01

    Evidence for a local 'Single Source' of cosmic rays is amassing by way of the recent precise measurements of various cosmic ray energy spectra from the AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons, positrons and antiprotons must now be added the determination of the boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high precision. Our analysis leads us to claim that, with certain assumptions about the propagation in the Galaxy, the results confirm our arguments regarding the presence of a local single source, perhaps, a supernova remnant (SNR). An attempt is made to determine some of the properties of this SNR and its progenitor star.

  10. Secondary Cosmic Ray Nuclei in the Light of the Single Source Model

    CERN Document Server

    Erlykin, Anatoly

    2016-01-01

    Evidence for a local 'Single Source' of cosmic rays is amassing by way of the recent precise measurements of various cosmic ray energy spectra from the AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons, positrons and antiprotons must now be added the determination of the boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high precision. Our analysis leads us to claim that, with certain assumptions about propagation in the Galaxy, the results confirm our arguments regarding the presence of a local single source, perhaps, a supernova remnant (SNR). An attempt is made to determine some of the properties of this SNR and its progenitor star.

  11. Cosmic ray interactions in the solar system: The Gerasimova-Zatsepin effect

    CERN Document Server

    van Eijden, J V R; Timmermans, C J W P

    2016-01-01

    The Gerasimova-Zatsepin effect of collisions of ultra-high-energy cosmic ray nuclei with photons emitted by the sun may cause two simultaneous air showers on Earth. This effect is simulated using the full energy spectrum of solar photons, ray tracing through the interplanetary magnetic field and upper limit values for the iron and oxygen cosmic ray fluxes. Only the most abundant interactions in which a single proton is emitted from the nucleus are considered. For the first time the distributions of distances between the individual showers at Earth as a function of the distance of the primary cosmic ray to the Sun are shown. These distributions are used to estimate the capabilities of current detector arrays to measure the Gerasimova-Zatsepin effect and to show that a dedicated array is capable of measuring this effect.

  12. The end of the galactic cosmic-ray energy spectrum - a phenomenological view

    CERN Document Server

    Hörandel, J R; Timokhin, A V; Hoerandel, Joerg R.

    2005-01-01

    Two structures in the all-particle energy spectrum of cosmic rays, the knee at 4 PeV and the second knee around 400 PeV are proposed to be explained by a phenomenological model, the poly gonato model, connecting direct and indirect measurements. Within this approach the knee is caused by a successive cut-off of the flux for individual elements starting with protons at 4.5 PeV. The second knee is interpreted as the end of the stable nuclei of the periodic table. To check some key features of this model calculations of the cosmic ray energy spectrum and the propagation path length at energies from 10^14 to 10^19 eV have been performed within the framework of a combined approach based on the diffusion model of cosmic rays and a direct simulation of charged-particle trajectories in the Galaxy.

  13. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    CERN Document Server

    Aplin, Karen

    2015-01-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing traditionally distinct scientific boundaries. Following the paper of Erlykin et al. (Astropart. Phys. 57--58 (2014) 26--29) we develop the interpretation of observed changes in long-wave (LW) radiation (Aplin and Lockwood, Env. Res. Letts. 8, 015026 (2013)), by taking account of cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected were not caused by individual cosmic ray primaries -- not b...

  14. Elemental energy spectra of cosmic rays measured by CREAM-II

    CERN Document Server

    Maestro, P; Allison, P; Bagliesi, M G; Barbier, L; Beatty, J J; Bigongiari, G; Brandt, T J; Childers, J T; Conklin, N B; Coutu, S; DuVernois, M A; Ganel, O; Han, J H; Jeon, J A; Kim, K C; Lee, M H; Malinine, A; Marrocchesi, P S; Minnick, S; Mognet, S I; Nam, S W; Nutter, S; Park, I H; Park, N H; Seo, E S; Sina, R; Walpole, P; Wu, J; Yang, J; Yoon, Y S; Zei, R; Zinn, S Y

    2010-01-01

    We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment CREAM (Cosmic Ray Energetics And Mass). The instrument (CREAM-II) was comprised of detectors based on different techniques (Cherenkov light, specific ionization in scintillators and silicon sensors) to provide a redundant charge identification and a thin ionization calorimeter capable of measuring the energy of cosmic rays up to several hundreds of TeV. The data analysis is described and the individual energy spectra of C, O, Ne, Mg, Si and Fe are reported up to ~ 10^14 eV. The spectral shape looks nearly the same for all the primary elements and can be expressed as a power law in energy E^{-2.66+/-0.04}. The nitrogen absolute intensity in the energy range 100-800 GeV/n is also measured.

  15. Semi-implicit anisotropic cosmic ray transport on an unstructured moving mesh

    CERN Document Server

    Pakmor, Ruediger; Simpson, Christine M; Kannan, Rahul; Springel, Volker

    2016-01-01

    In the interstellar medium of galaxies and the intracluster gas of galaxy clusters, the charged particles making up cosmic rays are moving almost exclusively along (but not across) magnetic field lines. The resulting anisotropic transport of cosmic rays in the form of diffusion or streaming not only affects the gas dynamics but also rearranges the magnetic fields themselves. The coupled dynamics of magnetic fields and cosmic rays can thus impact the formation and evolution of galaxies and the thermal evolution of galaxy clusters in critical ways. Numerically studying these effects requires solvers for anisotropic diffusion that are accurate, efficient, and robust, requirements that have proven difficult to satisfy in practice. Here, we present an anisotropic diffusion solver on an unstructured moving mesh that is conservative, does not violate the entropy condition, allows for semi-implicit time integration with individual timesteps, and only requires solving a single linear system of equations per timestep. ...

  16. Spherule Beds 3.47-3.24 Billion Years Old in the Barberton Greenstone Belt, South Africa: A Record of Large Meteorite Impacts and Their Influence on Early Crustal and Biological Evolution

    Science.gov (United States)

    Lowe, Donald R.; Byerly, Gary R.; Kyte, Frank T.; Shukolyukov, Alexander; Asaro, Frank; Krull, Alexander

    2003-01-01

    Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in S3 and S4 locally equal or exceed chondritic values but in other sections are at or only slightly above background. Most spherules are inferred to have formed by condensation of impact-produced rock vapor clouds, although some may represent ballistically ejected liquid droplets. Extreme Ir abundances and heterogeneity may reflect element fractionation during spherule formation, hydraulic fractionation during deposition, and/or diagenetic and metasomatic processes. Deposition of S1, S2, and S3 was widely influenced by waves and/or currents interpreted to represent impact-generated tsunamis, and S1 and S2 show multiple graded layers indicating the passage of two or more wave trains. These tsunamis may have promoted mixing within a globally stratified ocean, enriching surface waters in nutrients for biological communities. S2 and S3 mark the transition from the 300-million-year-long Onverwacht stage of predominantly basaltic and komatiitic volcanism to the late orogenic stage of greenstone belt evolution, suggesting that regional and possibly global tectonic reorganization resulted from these large impacts. These beds provide the oldest known direct record of terrestrial impacts and an opportunity to explore their influence on early life, crust, ocean, and atmosphere. The apparent presence of impact clusters at 3.26-3.24 Ga and approx. 2.65-2.5 Ga suggests either spikes in impact rates during the Archean or that the entire Archean was characterized by terrestrial impact rates above those currently estimated from the lunar cratering record.

  17. Spherule Beds 3.47-3.24 Billion Years Old in the Barberton Greenstone Belt, South Africa: A Record of Large Meteorite Impacts and Their Influence on Early Crustal and Biological Evolution

    Science.gov (United States)

    Lowe, Donald R.; Byerly, Gary R.; Kyte, Frank T.; Shukolyukov, Alexander; Asaro, Frank; Krull, Alexander

    2003-01-01

    Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in S3 and S4 locally equal or exceed chondritic values but in other sections are at or only slightly above background. Most spherules are inferred to have formed by condensation of impact-produced rock vapor clouds, although some may represent ballistically ejected liquid droplets. Extreme Ir abundances and heterogeneity may reflect element fractionation during spherule formation, hydraulic fractionation during deposition, and/or diagenetic and metasomatic processes. Deposition of S1, S2, and S3 was widely influenced by waves and/or currents interpreted to represent impact-generated tsunamis, and S1 and S2 show multiple graded layers indicating the passage of two or more wave trains. These tsunamis may have promoted mixing within a globally stratified ocean, enriching surface waters in nutrients for biological communities. S2 and S3 mark the transition from the 300-million-year-long Onverwacht stage of predominantly basaltic and komatiitic volcanism to the late orogenic stage of greenstone belt evolution, suggesting that regional and possibly global tectonic reorganization resulted from these large impacts. These beds provide the oldest known direct record of terrestrial impacts and an opportunity to explore their influence on early life, crust, ocean, and atmosphere. The apparent presence of impact clusters at 3.26-3.24 Ga and approx. 2.65-2.5 Ga suggests either spikes in impact rates during the Archean or that the entire Archean was characterized by terrestrial impact rates above those currently estimated from the lunar cratering record.

  18. Spiral arms as cosmic ray source distributions

    Science.gov (United States)

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

    2015-04-01

    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

  19. GNSS Radio Occultation Observations as a data source for Ionospheric Assimilation: COSMIC-1 & COSMIC-2

    Science.gov (United States)

    Yue, X.; Schreiner, W. S.; Kuo, Y. H.

    2014-12-01

    Since the pioneer GPS/MET mission, low Earth orbit (LEO) based global navigation satellite system (GNSS) Radio Occultation (RO) technique has been a powerful technique in ionosphere monitoring. After that, many LEO satellites were launched with RO payload, include: CHAMP , GRACE, SAC-C/D, COSMIC, C/NOFS, Metop-A/B, TerraSAR-X/TanDEM-X, and etc. COSMIC was the first constellation of satellites dedicated primarily to RO and delivering RO data in near real time. Currently in UCAR CDAAC, we process most of these missions' RO data for the community. Due to the success of COSMIC mission, a follow on mission called COSMIC-2 will be launched in 2016 and 2018, respectively. The COSMIC-2 RO data will be 4-6 times of COSMIC due to the doubled satellite and GNSS signals. In this paper we will describe: (1) Data process and quality in UCAR/CDAAC; (2) Ionospheric data assimilation results based on COSMIC data; (3) OSSE study for COSMIC-2.

  20. The chemical composition of the cosmic radiation around the ankle and the related spectral indices

    CERN Document Server

    Codino, Antonio

    2009-01-01

    Some recent measurements of the chemical composition of the cosmic radiation indicate that at the energy of 3 x 10 **18 eV, around the ankle, light cosmic ions dominate the spectrum as it occurs in the preknee energy region. Taking advantage of a recent theory of cosmic radiation which provides a quantitative explanation of the knee, the second knee and the ankle, the chemical composition of cosmic radiation is explicitly calculated giving individual ion spectra and ion fractions from 10 ** 12 eV to 5 x 10 ** 19 eV. The calculation assumes two components of the cosmic radiation feeding the ion flux at Earth: one originated in the disc volume and another one, called extradisc component, which from the disc boundaries traverses the Galaxy reaching the solar system. Data above 10 ** 17 eV collected during half century of experimentation by Auger, HiRes, Agasa, Akeno, Fly' s Eye, Yakutsk, Haverah Park and Volcano Ranch experiments are reviewed, examined and compared with the theoretical . The comparison between c...

  1. Harmonic Gravitational Wave Spectra of Cosmic String Loops in the Galaxy

    CERN Document Server

    DePies, Matthew R

    2009-01-01

    A new candidate source of gravitational radiation is described: the nearly-perfect harmonic series from individual loops of cosmic string. It is argued that theories with light cosmic strings give rise to a population of numerous long-lived stable loops, many of which cluster gravitationally in galaxy halos along with the dark matter. Each cosmic string loop produces a spectrum of discrete frequencies in a nearly perfect harmonic series, a fundamental mode and its integer multiples. The gravitational wave signal from cosmic string loops in our Galactic halo is analyzed numerically and it is found that the for light strings, the nearest loops typically produce strong signals which stand out above confusion noise from Galactic binaries. The total population of cosmic string loops in the Milky Way also produces a broad signal that acts as a confusion noise. Both signals are enhanced by the clustering of loops gravitationally bound to the Galaxy, which significantly decreases the average distance from the solar s...

  2. Longitudinal development of giant air showers and problem of estimating primary cosmic particle energy

    CERN Document Server

    Antonov, E E; Fedunin, E Y; Kirillov, A A; Roganova, T M; Fedorova, G F

    2002-01-01

    The attenuation length of the parameter rho sub 6 sub 0 sub 0 may differ as such as 40-50 % from the adopted one in experiments for the individual giant air showers. Thus the reliability of the experimental estimates of the primary-cosmic-particle energy in the region of superhigh energies may be doubtful. Cascade curves for electron and muon densities and similar cascade curves for total number of particles are built. Individual and mean cascade curves are approximated

  3. Cosmic web reconstruction through density ridges: catalogue

    Science.gov (United States)

    Chen, Yen-Chi; Ho, Shirley; Brinkmann, Jon; Freeman, Peter E.; Genovese, Christopher R.; Schneider, Donald P.; Wasserman, Larry

    2016-10-01

    We construct a catalogue for filaments using a novel approach called SCMS (subspace constrained mean shift). SCMS is a gradient-based method that detects filaments through density ridges (smooth curves tracing high-density regions). A great advantage of SCMS is its uncertainty measure, which allows an evaluation of the errors for the detected filaments. To detect filaments, we use data from the Sloan Digital Sky Survey, which consist of three galaxy samples: the NYU main galaxy sample (MGS), the LOWZ sample and the CMASS sample. Each of the three data set covers different redshift regions so that the combined sample allows detection of filaments up to z = 0.7. Our filament catalogue consists of a sequence of two-dimensional filament maps at different redshifts that provide several useful statistics on the evolution cosmic web. To construct the maps, we select spectroscopically confirmed galaxies within 0.050 < z < 0.700 and partition them into 130 bins. For each bin, we ignore the redshift, treating the galaxy observations as a 2-D data and detect filaments using SCMS. The filament catalogue consists of 130 individual 2-D filament maps, and each map comprises points on the detected filaments that describe the filamentary structures at a particular redshift. We also apply our filament catalogue to investigate galaxy luminosity and its relation with distance to filament. Using a volume-limited sample, we find strong evidence (6.1σ-12.3σ) that galaxies close to filaments are generally brighter than those at significant distance from filaments.

  4. Large Angular Scale Anisotropy in Cosmic Microwave Background Induced by Cosmic Strings

    Energy Technology Data Exchange (ETDEWEB)

    Allen, B.; Caldwell, R.R.; Shellard, E.P.; Stebbins, A.; Veeraraghavan, S. [Department of Physics, University of Wisconsin---Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)]|[University of Cambridge, Department of Applied Mathematics and Theoretical Physics, Silver Street, Cambridge CB3 9EW (United Kingdom)]|[NASA/Fermilab Astrophysics Center, P.O. Box 500, Batavia, Illinois 60510 (United States)]|[NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

    1996-10-01

    We simulate the anisotropy in the cosmic microwave background (CMB) induced by cosmic strings. By numerically evolving a network of cosmic strings we generate full-sky CMB temperature anisotropy maps. Based on 192 maps, we compute the anisotropy power spectrum for multipole moments l{le}20. By comparing with the observed temperature anisotropy, we set the normalization for the cosmic string mass per unit length {mu}, obtaining {ital G}{mu}/{ital c}{sup 2}=1.05{sub {minus}0.20}{sup +0.35}{times}10{sup {minus}6}, which is consistent with all other observational constraints on cosmic strings. We demonstrate that the anisotropy pattern is consistent with a Gaussian random field on large angular scales. {copyright} {ital 1996 The American Physical Society.}

  5. One century of cosmic rays – A particle physicist's view

    Directory of Open Access Journals (Sweden)

    Sutton Christine

    2015-01-01

    Full Text Available Experiments on cosmic rays and the elementary particles share a common history that dates back to the 19th century. Following the discovery of radioactivity in the 1890s, the paths of the two fields intertwined, especially during the decades after the discovery of cosmic rays. Experiments demonstrated that the primary cosmic rays are positively charged particles, while other studies of cosmic rays revealed various new sub-atomic particles, including the first antiparticle. Techniques developed in common led to the birth of neutrino astronomy in 1987 and the first observation of a cosmic γ-ray source by a ground-based cosmic-ray telescope in 1989.

  6. Galactic cosmic radiation environment models

    Science.gov (United States)

    Badhwar, G. D.; O'Neill, P. M.; Troung, A. G.

    2001-02-01

    Models of the radiation environment in free space and in near earth orbits are required to estimate the radiation dose to the astronauts for Mars, Space Shuttle, and the International Space Station missions, and to estimate the rate of single event upsets and latch-ups in electronic devices. Accurate knowledge of the environment is critical for the design of optimal shielding during both the cruise phase and for a habitat on Mars or the Moon. Measurements of the energy spectra of galactic cosmic rays (GCR) have been made for nearly four decades. In the last decade, models have been constructed that can predict the energy spectra of any GCR nuclei to an accuracy of better than 25%. Fresh and more accurate measurements have been made in the last year. These measurements can lead to more accurate models. Improvements in these models can be made in determining the local interstellar spectra and in predicting the level of solar modulation. It is the coupling of the two that defines a GCR model. This paper reviews of two of the more widely used models, and a comparison of their predictions with new proton and helium data from the Alpha Magnetic Spectrometer (AMS), and spectra of beryllium to iron in the ~40 to 500 MeV/n acquired by the Advanced Composition Explorer (ACE) during the 1997-98 solar minimum. Regressions equations relating the IMP-8 helium count rate to the solar modulation deceleration parameter calculated using the Climax neutron monitor rate have been developed and may lead to improvements in the predictive capacity of the models. .

  7. Cosmographic Constraints and Cosmic Fluids

    Directory of Open Access Journals (Sweden)

    Salvatore Capozziello

    2013-12-01

    Full Text Available The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations of state evolve as the universe expands, giving rise to the accelerated expansion. We describe in detail the ΛCDM (Λ-Cold Dark Matter and ωCDM models, considering also some specific examples, e.g., Chevallier–Polarsky–Linder, the Chaplygin gas and the Dvali–Gabadadze–Porrati cosmological model. Finally, we consider the cosmological consequences of f(R and f(T gravities and their impact on the framework of cosmography. Keeping these considerations in mind, we point out the model-independent procedure related to cosmography, showing how to match the series of cosmological observables to the free parameters of each model. We critically discuss the role played by cosmography, as a selection criterion to check whether a particular model passes or does not present cosmological constraints. In so doing, we find out cosmological bounds by fitting the luminosity distance expansion of the redshift, z, adopting the recent Union 2.1 dataset of supernovae, combined with the baryonic acoustic oscillation and the cosmic microwave background measurements. We perform cosmographic analyses, imposing different priors on the Hubble rate present value. In addition, we compare our results with recent PLANCK limits, showing that the ΛCDM and ωCDM models seem to be the favorite with respect to other dark energy models. However, we show that cosmographic constraints on f(R and f(T cannot discriminate between extensions of General Relativity and dark energy models, leading to a disadvantageous degeneracy problem.

  8. The Cosmic Infrared Background Experiment

    Science.gov (United States)

    Bock, James; Battle, J.; Cooray, A.; Hristov, V.; Kawada, M.; Keating, B.; Lee, D.; Matsumoto, T.; Matsuura, S.; Nam, U.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.; Zemcov, M.

    2009-01-01

    We are developing the Cosmic Infrared Background ExpeRiment (CIBER) to search for signatures of first-light galaxy emission in the extragalactic background. The first generation of stars produce characteristic signatures in the near-infrared extragalactic background, including a redshifted Ly-cutoff feature and a characteristic fluctuation power spectrum, that may be detectable with a specialized instrument. CIBER consists of two wide-field cameras to measure the fluctuation power spectrum, and a low-resolution and a narrow-band spectrometer to measure the absolute background. The cameras will search for fluctuations on angular scales from 7 arcseconds to 2 degrees, where the first-light galaxy spatial power spectrum peaks. The cameras have the necessary combination of sensitivity, wide field of view, spatial resolution, and multiple bands to make a definitive measurement. CIBER will determine if the fluctuations reported by Spitzer arise from first-light galaxies. The cameras observe in a single wide field of view, eliminating systematic errors associated with mosaicing. Two bands are chosen to maximize the first-light signal contrast, at 1.6 um near the expected spectral maximum, and at 1.0 um; the combination is a powerful discriminant against fluctuations arising from local sources. We will observe regions of the sky surveyed by Spitzer and Akari. The low-resolution spectrometer will search for the redshifted Lyman cutoff feature in the 0.7 - 1.8 um spectral region. The narrow-band spectrometer will measure the absolute Zodiacal brightness using the scattered 854.2 nm Ca II Fraunhofer line. The spectrometers will test if reports of a diffuse extragalactic background in the 1 - 2 um band continues into the optical, or is caused by an under estimation of the Zodiacal foreground. We report performance of the assembled and tested instrument as we prepare for a first sounding rocket flight in early 2009. CIBER is funded by the NASA/APRA sub-orbital program.

  9. Cosmology Quantized in Cosmic Time

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, M

    2004-06-03

    This paper discusses the problem of inflation in the context of Friedmann-Robertson-Walker Cosmology. We show how, after a simple change of variables, to quantize the problem in a way which parallels the classical discussion. The result is that two of the Einstein equations arise as exact equations of motion and one of the usual Einstein equations (suitably quantized) survives as a constraint equation to be imposed on the space of physical states. However, the Friedmann equation, which is also a constraint equation and which is the basis of the Wheeler-deWitt equation, acquires a welcome quantum correction that becomes significant for small scale factors. We discuss the extension of this result to a full quantum mechanical derivation of the anisotropy ({delta} {rho}/{rho}) in the cosmic microwave background radiation, and the possibility that the extra term in the Friedmann equation could have observable consequences. To clarify the general formalism and explicitly show why we choose to weaken the statement of the Wheeler-deWitt equation, we apply the general formalism to de Sitter space. After exactly solving the relevant Heisenberg equations of motion we give a detailed discussion of the subtleties associated with defining physical states and the emergence of the classical theory. This computation provides the striking result that quantum corrections to this long wavelength limit of gravity eliminate the problem of the big crunch. We also show that the same corrections lead to possibly measurable effects on the CMB radiation. For the sake of completeness, we discuss the special case, {lambda} = 0, and its relation to Minkowski space. Finally, we suggest interesting ways in which these techniques can be generalized to cast light on the question of chaotic or eternal inflation. In particular, we suggest one can put an experimental lower bound on the distance to a universe with a scale factor very different from our own, by looking at its effects on our CMB

  10. Cosmic Disasters, Real and Imagined

    Science.gov (United States)

    Harris, Alan W.

    2010-05-01

    Since ancient times, humans have looked to the skies for explanations of past tragedies and predictions of the future. Indeed the very word "disaster” means "bad star". Although most such myths and forecasts are purely imaginary, we have, in more recent times, identified real cosmic impact events in the past and we have developed the necessary tools to discover and predict them in the near-term future. We dynamical astronomers, the direct descendants of ancient astrologers, have at last gained the tools to actually deliver on at least some of the promises of ancient astrologers, to predict "Armageddon” before it arrives. Nevertheless, we still carry some baggage of mythos, ancient disasters blamed on impacts that never happened, and obsessions over impacts of such incredible improbability that we would better worry about other things. In this talk I will review our present state of knowledge of what is out there that might hit us and with what frequency, the estimated consequences of impacts of all sizes, and from these derive an "actuarial” impact risk assessment. I will present the "intrinsic risk", before any Earth-approaching asteroids were discovered; where we are now with the present level of survey completeness; and where future surveys should take us. I will put this in the context of risk levels from other natural, and un-natural, hazards. I will close with a brief discussion of a claimed impact that almost certainly did not happen, relating to the extinction of megafauna in North America 12,900 years ago. The mythos underlying this claim may provide an object lesson on the present day "street fight” over the reality of global warming.

  11. Cosmic Microwave Background Data Analysis

    Science.gov (United States)

    Paykari, Paniez; Starck, Jean-Luc Starck

    2012-03-01

    About 400,000 years after the Big Bang the temperature of the Universe fell to about a few thousand degrees. As a result, the previously free electrons and protons combined and the Universe became neutral. This released a radiation which we now observe as the cosmic microwave background (CMB). The tiny fluctuations* in the temperature and polarization of the CMB carry a wealth of cosmological information. These so-called temperature anisotropies were predicted as the imprints of the initial density perturbations which gave rise to the present large-scale structures such as galaxies and clusters of galaxies. This relation between the present-day Universe and its initial conditions has made the CMB radiation one of the most preferred tools to understand the history of the Universe. The CMB radiation was discovered by radio astronomers Arno Penzias and Robert Wilson in 1965 [72] and earned them the 1978 Nobel Prize. This discovery was in support of the Big Bang theory and ruled out the only other available theory at that time - the steady-state theory. The crucial observations of the CMB radiation were made by the Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on the Cosmic Background Explorer (COBE) satellite [86]- orbited in 1989-1996. COBE made the most accurate measurements of the CMB frequency spectrum and confirmed it as being a black-body to within experimental limits. This made the CMB spectrum the most precisely measured black-body spectrum in nature. The CMB has a thermal black-body spectrum at a temperature of 2.725 K: the spectrum peaks in the microwave range frequency of 160.2 GHz, corresponding to a 1.9mmwavelength. The results of COBE inspired a series of ground- and balloon-based experiments, which measured CMB anisotropies on smaller scales over the next decade. During the 1990s, the first acoustic peak of the CMB power spectrum (see Figure 5.1) was measured with increasing sensitivity and by 2000 the BOOMERanG experiment [26] reported

  12. Extraterrestrial components from deep sea sediments of Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.

    common formation process. Pulse heating during atmospheric entry of the particle seems to be a competent procedure for PGE segregation into nuggets. Glass Cosmic Spherules Observation of 36 glass spherules that has smooth and spherical external features...

  13. Cosmic rays, geomagnetic field and climate changes

    Science.gov (United States)

    Shea, M.; Smart, D.

    The possibility of a connection between cosmic radiation and climate has intrigued scientists for the past several decades. The recent studies of Friis -Christensen and Svensmark has shown an observed variation of 3-4% of the global cloud cover between 1980 and 1995 that appeared to be directly correlated with the change in galactic cosmic radiation flux over the solar cycle. However, in studies of this type, not only the solar cycle modulation of cosmic radiation must be considered, but also the changes in the cosmic radiation impinging at the top of the atmosphere as a result of the long term evolution of the geomagnetic field. We present preliminary results of an on-going study of geomagnetic cutoff rigidities over a 400-year interval. These results show (1) the change in cutoff rigidity is sufficient large so that the change in cosmic radiation flux impacting the earth is approximately equal to the relative change in flux over a solar cycle, and (2) the changes in cutoff rigidity are non- uniform over the globe with both significant increases and decreases at mid-latitude locations.

  14. Jupiter as a Giant Cosmic Ray Detector

    CERN Document Server

    Rimmer, Paul B; Helling, Christiane

    2014-01-01

    We explore the feasibility of using the atmosphere of Jupiter to detect Ultra-High-Energy Cosmic Rays (UHECR's). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmic ray "detector" area of $3.3 \\times 10^7$ km$^2$. We predict that Fermi-LAT should be able to detect events of energy $>10^{21}$ eV with fluence $10^{-7}$ erg cm$^{-2}$ at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays $\\gtrsim 10^{20}$ eV. Extensive air showers also produce a synchrotron signature that may ...

  15. Polycyclic aromatic hydrocarbon processing by cosmic rays

    CERN Document Server

    Micelotta, E R; Tielens, A G G M

    2010-01-01

    Context: Cosmic rays are present in almost all phases of the ISM. PAHs and cosmic rays represent an abundant and ubiquitous component of the interstellar medium. However, the interaction between them has never before been fully investigated. Aims: To study the effects of cosmic ray ion (H, He, CNO and Fe-Co-Ni) and electron bombardment of PAHs in galactic and extragalactic environments. Methods: We calculate the nuclear and electronic interactions for collisions between PAHs and cosmic ray ions and electrons with energies between 5 MeV/nucleon and 10 GeV, above the threshold for carbon atom loss, in normal galaxies, starburst galaxies and cooling flow galaxy clusters. Results: The timescale for PAH destruction by cosmic ray ions depends on the electronic excitation energy Eo and on the amount of energy available for dissociation. Small PAHs are destroyed faster, with He and the CNO group being the more effective projectiles. For electron collisions, the lifetime is independent of the PAH size and varies with ...

  16. Bayesian Cosmic Web Reconstruction: BARCODE for Clusters

    Science.gov (United States)

    Bos, E. G. Patrick; van de Weygaert, Rien; Kitaura, Francisco; Cautun, Marius

    2016-10-01

    We describe the Bayesian \\barcode\\ formalism that has been designed towards the reconstruction of the Cosmic Web in a given volume on the basis of the sampled galaxy cluster distribution. Based on the realization that the massive compact clusters are responsible for the major share of the large scale tidal force field shaping the anisotropic and in particular filamentary features in the Cosmic Web. Given the nonlinearity of the constraints imposed by the cluster configurations, we resort to a state-of-the-art constrained reconstruction technique to find a proper statistically sampled realization of the original initial density and velocity field in the same cosmic region. Ultimately, the subsequent gravitational evolution of these initial conditions towards the implied Cosmic Web configuration can be followed on the basis of a proper analytical model or an N-body computer simulation. The BARCODE formalism includes an implicit treatment for redshift space distortions. This enables a direct reconstruction on the basis of observational data, without the need for a correction of redshift space artifacts. In this contribution we provide a general overview of the the Cosmic Web connection with clusters and a description of the Bayesian BARCODE formalism. We conclude with a presentation of its successful workings with respect to test runs based on a simulated large scale matter distribution, in physical space as well as in redshift space.

  17. Supermassive screwed cosmic string in dilaton gravity

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, V B [Departamento de Fisica, Universidade Federal da ParaIba, 58059-970, Joao Pessoa, PB (Brazil); Ferreira, Cristine N [Nucleo de Fisica, Centro Federal de Educacao Tecnologica de Campos, Rua Dr Siqueira, 273-Parque Dom Bosco, 28030-130, Campos dos Goytacazes, RJ (Brazil); Cuesta, H J Mosquera [Instituto de Cosmologia, Relatividade e AstrofIsica (ICRA-BR), Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Urca 22290-180, Rio de Janeiro, RJ (Brazil)

    2006-06-21

    The early universe might have undergone phase transitions at energy scales much higher than the one corresponding to the grand unified theories (GUT) scales. At these higher energy scales, the transition at which gravity separated from all other interactions, the so-called Planck era, more massive strings called supermassive cosmic strings could have been produced, with energy of about 10{sup 19} GeV. The dynamics of strings formed with this energy scale cannot be described by means of the weak-field approximation, as in the standard procedure for ordinary GUT cosmic strings. As suggested by string theories, at this extreme energy, gravity may be transmitted by some kind of scalar field (usually called the dilaton) in addition to the tensor field of Einstein's theory of gravity. It is then permissible to tackle the issue regarding the dynamics of supermassive cosmic strings within this framework. With this aim, we obtain the gravitational field of a supermassive screwed cosmic string in a scalar-tensor theory of gravity. We show that for the supermassive configuration, exact solutions of scalar-tensor screwed cosmic strings can be found in connection with the Bogomol'nyi limit. We show that the generalization of Bogomol'nyi arguments to the Brans-Dicke theory is possible when torsion is present and we obtain an exact solution in this supermassive regime, with the dilaton solution obtained by consistency with internal constraints.

  18. CMB Constraints on Cosmic Strings and Superstrings

    CERN Document Server

    Charnock, Tom; Copeland, Edmund J; Moss, Adam

    2016-01-01

    We present the first complete MCMC analysis of cosmological models with evolving cosmic (super)string networks, using the Unconnected Segment Model in the unequal-time correlator formalism. For ordinary cosmic string networks, we derive joint constraints on {\\Lambda}CDM and string network parameters, namely the string tension G{\\mu}, the loop-chopping efficiency c_r and the string wiggliness {\\alpha}. For cosmic superstrings, we obtain joint constraints on the fundamental string tension G{\\mu}_F, the string coupling g_s, the self-interaction coefficient c_s, and the volume of compact extra dimensions w. This constitutes the most comprehensive CMB analysis of {\\Lambda}CDM cosmology + strings to date. For ordinary cosmic string networks our updated constraint on the string tension is, in relativistic units, G{\\mu}<1.1x10^-7, while for cosmic superstrings our constraint on the fundamental string tension is G{\\mu}_F<2.8x10^-8, both obtained using Planck2015 temperature and polarisation data.

  19. Cosmic Ray Interactions in Shielding Materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-08

    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.

  20. Simulating the microdosimetry of cosmic electrons

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Abel A.; Oliveira, Cassia F. Silva, E-mail: abel@ieav.cta.br [Instituto de Estudos Avancados (IEAV), Sao Jose dos Campos, SP (Brazil). Divisao de Energia Nuclear

    2015-07-01

    The human presence in space is a matter of concern especially regarding the deleterious effects of the cosmic radiation. Doses in astronauts during space missions must be closely monitored. On the other hand, the development of organic electronics with applications to the monitoring of physiological functions through the implant of electronic devices under the skin is coming to become a reality in the near future. Therefore, doses in astronauts can affect not only the biological tissue, but also the electronic one represented by silicon (Si). In some orbital regions around the Earth, cosmic electrons are predominant with energies ranging from keV to MeV. In this study, the lineal energy (LE) and the absorbed dose (AD) from cosmic electron flux based on the AE8MAX model are simulated for microscopic sites (radius = 1μm) of tissue equivalent material (TEM) and Si at a depth of 100 μm in the skin using the Monte Carlo N-Particle code for uncertainties < 10%. Cosmic electrons yielded LE decreasing with the energy of particles crossing the sites. Maximum values of LE were around 0.7 eV/μm for cosmic electron energies of 100 keV. LE for Si sites was up to 3.7 times higher than that for TEM ones, increasing with particle's energy. Maximum values of AD were around 54 μGy for TEM sites and 40 μGy for Si ones. (author)

  1. Review article: Cosmology with cosmic shear observations

    CERN Document Server

    Kilbinger, Martin

    2014-01-01

    Cosmic shear is the distortion of images of distant galaxies due to weak gravitational lensing by the large-scale structure in the Universe. Such images are coherently deformed by the tidal field of matter inhomogeneities along the line of sight. By measuring galaxy shape correlations, we can study the properties and evolution of structure on large scales as well as the geometry of the Universe. Thus, cosmic shear has become a powerful probe into the nature of dark matter and the origin of the current accelerated expansion of the Universe. Over the last years, cosmic shear has evolved into a reliable and robust cosmological probe, providing measurements of the expansion history of the Universe and the growth of its structure. We review here the principles of weak gravitational lensing and show how cosmic shear is interpreted in a cosmological context. Then we give an overview of weak-lensing measurements, and present the main observational cosmic-shear results since it was discovered 15 years ago, as well as ...

  2. LHCf sheds new light on cosmic rays

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    The energy spectrum of the single photon obtained using data from the LHCf experiment has turned out to be very different from that predicted by the theoretical models used until now to describe the interactions between very high-energy cosmic rays and the earth's atmosphere. The consequences of this discrepancy for cosmic ray studies could be significant.   Artistic impression of cosmic rays entering Earth's atmosphere. (Credit: Asimmetrie/Infn). It took physicists by surprise when analysis of the data collected by the two LHCf calorimeters in 2010 showed that high-energy cosmic rays don't interact with the atmosphere in the manner predicted by theory. The LHCf detectors, set up 140 metres either side of the ATLAS interaction point, are dedicated to the study of the secondary particles emitted at very small angles during proton-proton collisions in the LHC, with energies comparable to cosmic rays entering the earth's atmosphere at 2.5x1016 eV. The aim of the experiment is to r...

  3. Xenia: A Probe of Cosmic Chemical Evolution

    Science.gov (United States)

    Kouveliotou, Chryssa; Piro, L.

    2008-01-01

    Xenia is a concept study for a medium-size astrophysical cosmology mission addressing the Cosmic Origins key objective of NASA's Science Plan. The fundamental goal of this objective is to understand the formation and evolution of structures on various scales from the early Universe to the present time (stars, galaxies and the cosmic web). Xenia will use X-and y-ray monitoring and wide field X-ray imaging and high-resolution spectroscopy to collect essential information from three major tracers of these cosmic structures: the Warm Hot Intergalactic Medium (WHIM), Galaxy Clusters and Gamma Ray Bursts (GRBs). Our goal is to trace the chemo-dynamical history of the ubiquitous warm hot diffuse baryon component in the Universe residing in cosmic filaments and clusters of galaxies up to its formation epoch (at z =0-2) and to map star formation and galaxy metal enrichment into the re-ionization era beyond z 6. The concept of Xenia (Greek for "hospitality") evolved in parallel with the Explorer of Diffuse Emission and GRB Explosions (EDGE), a mission proposed by a multinational collaboration to the ESA Cosmic Vision 2015. Xenia incorporates the European and Japanese collaborators into a U.S. led mission that builds on the scientific objectives and technological readiness of EDGE.

  4. Stopping Cooling Flows with Cosmic Ray Feedback

    CERN Document Server

    Mathews, William G

    2009-01-01

    Multi-Gyr two-dimensional calculations describe the gasdynamical evolution of hot gas in the Virgo cluster resulting from intermittent cavities formed with cosmic rays. Without cosmic rays, the gas evolves into a cooling flow, depositing about 85 solar masses per year of cold gas in the cluster core -- such uninhibited cooling conflicts with X-ray spectra and many other observations. When cosmic rays are produced or deposited 10 kpc from the cluster center in bursts of about 10^{59} ergs lasting 20 Myrs and spaced at intervals of 200 Myrs, the central cooling rate is greatly reduced to 0.1 - 1 solar masses per year, consistent with observations. After cosmic rays diffuse through the cavity walls, the ambient gas density is reduced and is buoyantly transported 30-70 kpc out into the cluster. Cosmic rays do not directly heat the gas and the modest shock heating around young cavities is offset by global cooling as the cluster gas expands. After several Gyrs the hot gas density and temperature profiles remain sim...

  5. Cosmic ray-driven winds in the Galactic environment and the cosmic ray spectrum

    Science.gov (United States)

    Recchia, S.; Blasi, P.; Morlino, G.

    2017-09-01

    Cosmic rays escaping the Galaxy exert a force on the interstellar medium directed away from the Galactic disc. If this force is larger than the gravitational pull due to the mass embedded in the Galaxy, then galactic winds may be launched. Such outflows may have important implications for the history of star formation of the host galaxy, and in turn affect in a crucial way the transport of cosmic rays, both due to advection with the wind and to the excitation of waves by the same cosmic rays, through streaming instability. The possibility to launch cosmic ray-induced winds and the properties of such winds depend on environmental conditions, such as the density and temperature of the plasma at the base of the wind and the gravitational potential, especially the one contributed by the dark matter halo. In this paper, we make a critical assessment of the possibility to launch cosmic ray-induced winds for a Milky Way-like galaxy and how the properties of the wind depend upon the conditions at the base of the wind. Special attention is devoted to the implications of different conditions for wind launching on the spectrum of cosmic rays observed at different locations in the disc of the galaxy. We also comment on how cosmic ray-induced winds compare with recent observations of Oxygen absorption lines in quasar spectra and emission lines from blank sky, as measured by XMM-Newton/EPIC-MOS.

  6. He-3 in galactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Mewaldt, R.A.

    1986-12-01

    Cosmic-ray He-3/He-4 observations, including a new measurement around 65 MeV per nucleon from ISEE-3, are compared with interstellar propagation and solar modulation calculations in an effort to understand the origin of cosmic-ray He nuclei. A survey of spacecraft and balloon observations of the He-3/He-4 ratio shows improved consistency among measurements in the 50-300 MeV per nucleon energy range when a previously neglected contribution from atmospheric secondary He-3 is taken into account. These low-energy observations imply a mean escape length of 6-8 g/sq cm in the standard leaky box model for cosmic-ray propagation in the Galaxy, a value consistent with that derived from studies of heavier nuclei. No evidence is found for an excess of low-energy He-3 such as that reported at high energies. 42 references.

  7. Portable cosmic muon telescope for environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Barnafoeldi, Gergely Gabor [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, 29-33 Konkoly-Thege Miklos Str., H-1121 Budapest (Hungary); Hamar, Gergo [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, 29-33 Konkoly-Thege Miklos Str., H-1121 Budapest (Hungary); Department of Physics of Complex Systems, Eoetvoes University, 1/A Pazmany P. setany, H-1117 Budapest (Hungary); Melegh, Hunor Gergely [Budapest University of Technology and Economics, 3-9 Muegyetem rkp., H-1111 Budapest (Hungary); Olah, Laszlo [Department of Physics of Complex Systems, Eoetvoes University, 1/A Pazmany P. setany, H-1117 Budapest (Hungary); Suranyi, Gergely [Geological, Geophysical and Space Science Research Group of the HAS, Eoetvoes University, 1/C Pazmany P. setany, H-1117 Budapest (Hungary); Varga, Dezso, E-mail: dezso.varga@cern.ch [Department of Physics of Complex Systems, Eoetvoes University, 1/A Pazmany P. setany, H-1117 Budapest (Hungary)

    2012-10-11

    A portable, low power consumption cosmic muon tracking system based on Close Cathode MWPC technology is presented, which is designed for operation in highly humid environmental conditions such as underground caves, tunnels, or cellars. The system measures the angular distribution of cosmic muons with resolution of 10 mrad, allowing for a tomographic mapping of the soil density above the detector unit. The size of the detector, 0.1 m{sup 2} of total sensitive surface, was designed to fulfill the requirement of transport through humanly passable natural cave tunnels. First results from the Ariadne Cave System in Pilis Mountains, Hungary are shown, which constrains the necessary data taking time for meaningful tomographic mapping. -- Highlights: Black-Right-Pointing-Pointer Cosmic muon tracking system for underground applications presented. Black-Right-Pointing-Pointer Operation in highly humid environment of natural caves demonstrated. Black-Right-Pointing-Pointer Tomographic mapping at 60 m depth was performed during 50 days in Pilis Mountains, Hungary.

  8. Cosmic absorption of ultra high energy particles

    Science.gov (United States)

    Ruffini, R.; Vereshchagin, G. V.; Xue, S.-S.

    2016-02-01

    This paper summarizes the limits on propagation of ultra high energy particles in the Universe, set up by their interactions with cosmic background of photons and neutrinos. By taking into account cosmic evolution of these backgrounds and considering appropriate interactions we derive the mean free path for ultra high energy photons, protons and neutrinos. For photons the relevant processes are the Breit-Wheeler process as well as the double pair production process. For protons the relevant reactions are the photopion production and the Bethe-Heitler process. We discuss the interplay between the energy loss length and mean free path for the Bethe-Heitler process. Neutrino opacity is determined by its scattering off the cosmic background neutrino. We compute for the first time the high energy neutrino horizon as a function of its energy.

  9. Probing Cosmic Superstrings with Gravitational Waves

    CERN Document Server

    Sousa, Lara

    2016-01-01

    We compute the stochastic gravitational wave background generated by cosmic superstrings using a semi-analytical velocity-dependent model to describe their dynamics. We show that heavier string types may leave distinctive signatures on the stochastic gravitational wave background spectrum within the reach of present and upcoming gravitational wave detectors. We examine the physically motivated scenario in which the physical size of loops is determined by the gravitational backreaction scale and use NANOGRAV data to derive a conservative constraint of $G\\mu_F<3.2 \\times 10^{-9}$ on the tension of fundamental strings. We demonstrate that approximating the gravitational wave spectrum generated by cosmic superstring networks using the spectrum generated by ordinary cosmic strings with reduced intercommuting probability (which is often done in the literature) leads, in general, to weaker observational constraints on $G\\mu_F$. We show that the inclusion of heavier string types is required for a more accurate cha...

  10. Cosmic ray antiprotons at high energies

    Science.gov (United States)

    Winkler, Martin Wolfgang

    2017-02-01

    Cosmic ray antiprotons provide a powerful tool to probe dark matter annihilations in our galaxy. The sensitivity of this important channel is, however, diluted by sizable uncertainties in the secondary antiproton background. In this work, we improve the calculation of secondary antiproton production with a particular focus on the high energy regime. We employ the most recent collider data and identify a substantial increase of antiproton cross sections with energy. This increase is driven by the violation of Feynman scaling as well as by an enhanced strange hyperon production. The updated antiproton production cross sections are made publicly available for independent use in cosmic ray studies. In addition, we provide the correlation matrix of cross section uncertainties for the AMS-02 experiment. At high energies, the new cross sections improve the compatibility of the AMS-02 data with a pure secondary origin of antiprotons in cosmic rays.

  11. How Cosmic Web Detachment Drives Galaxy Quenching

    CERN Document Server

    Aragon-Calvo, Miguel A; Silk, Joseph

    2016-01-01

    We present the Cosmic Web Detachment (CWD) model, a conceptual framework to interpret galaxy evolution in a cosmological context, providing a direct link between the star formation history of galaxies and the cosmic web. The CWD model unifies several mechanism known to disrupt or stop star formation into one single physical process and provides a natural explanation for a wide range of galaxy properties. Galaxies begin accreting star-forming gas at early times via a network of primordial highly coherent filaments. The efficient star formation phase ends when non-linear interactions with other galaxies or elements of the cosmic web detach the galaxy from its network of primordial filaments, thus ending the efficient accretion of cold gas. The stripping of the filamentary web around galaxies is the physical process responsible of star formation quenching in gas stripping, harassment, strangulation and starvation. Being a purely gravitational/mechanical process CWD acts at a more fundamental level than internal ...

  12. Weak cosmic censorship: as strong as ever.

    Science.gov (United States)

    Hod, Shahar

    2008-03-28

    Spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. This is the essence of the weak cosmic censorship conjecture. The hypothesis, put forward by Penrose 40 years ago, is still one of the most important open questions in general relativity. In this Letter, we reanalyze extreme situations which have been considered as counterexamples to the weak cosmic censorship conjecture. In particular, we consider the absorption of scalar particles with large angular momentum by a black hole. Ignoring back reaction effects may lead one to conclude that the incident wave may overspin the black hole, thereby exposing its inner singularity to distant observers. However, we show that when back reaction effects are properly taken into account, the stability of the black-hole event horizon is irrefutable. We therefore conclude that cosmic censorship is actually respected in this type of gedanken experiments.

  13. Microphysics of cosmic ray driven plasma instabilities

    CERN Document Server

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

    2013-01-01

    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.

  14. Detecting the cosmic web with radio surveys

    CERN Document Server

    Vazza, F; Gheller, C; Ferrari, C; Bonafede, A

    2016-01-01

    We study the challenges to detect the cosmic web at radio wavelengths with state-of-the-art cosmological simulations of extragalactic magnetic fields. The incoming generation of radio surveys operating at low frequency, like LOFAR, SKA-LOW and MWA will have the best chance to detect the large-scale, low surface brightness emission from the shocked cosmic web. The detected radio emission will enable to constrain the average magnetisation level of the gas in filaments and the acceleration efficiency of electrons by strong shocks. In case of detections, through statistical modelling (e.g. correlation functions) it will be possible to discriminate among competing scenarios for the magnetisation of large-scale structures (i.e. astrophysical versus primordial scenarios), making radio surveys an important probe of cosmic magnetogenesis.

  15. Handbook of cosmic hazards and planetary defense

    CERN Document Server

    Allahdadi, Firooz

    2015-01-01

    Covers in a comprehensive fashion all aspects of cosmic hazards and possible strategies for contending with these threats through a comprehensive planetary defense strategy. This handbook brings together in a single reference work a rich blend of information about the various types of cosmic threats that are posed to human civilization by asteroids, comets, bolides, meteors, solar flares and coronal mass ejections, cosmic radiation and other types of threats that are only recently beginning to be understood and studied, such as investigation of the “cracks” in the protective shield provided by the Van Allen belts and the geomagnetosphere, of matter-antimatter collisions, orbital debris and radiological or biological contamination. Some areas that are addressed involve areas about which there is a good deal of information that has been collected for many decades by multiple space missions run by many different space agencies, observatories and scientific researchers. Other areas involving research and ...

  16. Magnetohydrodynamic experiments on cosmic magnetic fields

    CERN Document Server

    Stefani, Frank; Gerbeth, Gunter

    2008-01-01

    It is widely known that cosmic magnetic fields, including the fields of planets, stars, and galaxies, are produced by the hydromagnetic dynamo effect in moving electrically conducting fluids. It is less well known that cosmic magnetic fields play also an active role in cosmic structure formation by enabling outward transport of angular momentum in accretion disks via the magnetorotational instability (MRI). Considerable theoretical and computational progress has been made in understanding both processes. In addition to this, the last ten years have seen tremendous efforts in studying both effects in liquid metal experiments. In 1999, magnetic field self-excitation was observed in the large scale liquid sodium facilities in Riga and Karlsruhe. Recently, self-excitation was also obtained in the French "von Karman sodium" (VKS) experiment. An MRI-like mode was found on the background of a turbulent spherical Couette flow at the University of Maryland. Evidence for MRI as the first instability of an hydrodynamica...

  17. High Energy Cosmic Rays From Supernovae

    CERN Document Server

    Morlino, Giovanni

    2016-01-01

    Cosmic rays are charged relativistic particles that reach the Earth with extremely high energies, providing striking evidence of the existence of effective accelerators in the Universe. Below an energy around $\\sim 10^{17}$ eV cosmic rays are believed to be produced in the Milky Way while above that energy their origin is probably extragalactic. In the early '30s supernovae were already identified as possible sources for the Galactic component of cosmic rays. After the '70s this idea has gained more and more credibility thanks to the the development of the diffusive shock acceleration theory, which provides a robust theoretical framework for particle energization in astrophysical environments. Afterwards, mostly in recent years, much observational evidence has been gathered in support of this framework, converting a speculative idea in a real paradigm. In this Chapter the basic pillars of this paradigm will be illustrated. This includes the acceleration mechanism, the non linear effects produced by accelerate...

  18. Cosmic-ray diffusion in magnetized turbulence

    CERN Document Server

    Tautz, R C

    2015-01-01

    The problem of cosmic-ray scattering in the turbulent electromagnetic fields of the interstellar medium and the solar wind is of great importance due to the variety of applications of the resulting diffusion coefficients. Examples are diffusive shock acceleration, cosmic-ray observations, and, in the solar system, the propagation of coronal mass ejections. In recent years, it was found that the simple diffusive motion that had been assumed for decades is often in disagreement both with numerical and observational results. Here, an overview is given of the interaction processes of cosmic rays and turbulent electromagnetic fields. First, the formation of turbulent fields due to plasma instabilities is treated, where especially the non-linear behavior of the resulting unstable wave modes is discussed. Second, the analytical and the numerical side of high-energy particle propagation will be reviewed by presenting non-linear analytical theories and Monte-Carlo simulations. For the example of the solar wind, the im...

  19. Remarks on Cosmic Strings and Quantum Gravity

    CERN Document Server

    Anandan, Jeeva S

    1999-01-01

    A quantum equivalence principle is formulated by means of a gravitational phase operator which is an element of the Poincare group. This is applied to the spinning cosmic string which suggests that it may, but not necessarily, contain gravitational torsion. A new exact solution of the Einstein- Cartan-Sciama-Kibble equations for the gravitational field with torsion is obtained everywhere for a cosmic string with uniform energy density, spin density and flux. The quantization condition for fluxoid due to London and DeWitt is generalized to include the spin flux. A novel effect due to the quantized gravitational field of the cosmic string on the wave function of a particle outside the string is used to show that spacetime points are not meaningful in quantum gravity.

  20. Origin of the Cosmic Ray Spectral Hardening

    CERN Document Server

    Tomassetti, N

    2012-01-01

    Recent data from ATIC, CREAM and PAMELA indicate that the cosmic ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV per nucleon. We propose that the hardening is an interstellar propagation effect that originates from a spatial change of the cosmic ray transport properties in different regions of the Galaxy. The key hypothesis is that the diffusion coefficient is not separable into energy and space variables as usually assumed. Under this scenario, we can reproduce well the observational data. Our model has several implications for the cosmic ray acceleration/propagation physics and can be tested by ongoing experiments such as AMS or Fermi/LAT.

  1. A Common Solution of Two Cosmic Puzzles

    CERN Document Server

    Dado, Shlomo

    2014-01-01

    The origin of the diffuse extragalactic gamma-ray background, which was measured with the large area telescope (LAT) aboard the Fermi satellite at energy below 820 GeV, and of the diffuse cosmic background of neutrinos, which was observed at much higher energies with the IceCube detector deep under the south pole ice, are among the current unsolved major cosmic puzzles. Here we show that their properties indicate a common origin: the decay of mesons produced in collisions of cosmic rays accelerated in relativistic jets with matter in/near source. Moreover, their properties are those expected if their common source is the highly relativistic jets that produce the long duration gamma ray bursts in core collapse supernovae of type Ic, which take place mostly in the densest regions of giant molecular clouds in star forming galaxies.

  2. Electromagnetic radiation of superconducting cosmic strings

    Science.gov (United States)

    Rogozin, D. A.; Zadorozhna, L. V.

    2013-12-01

    Cosmic strings are relics of the early Universe which can be formed during the phase transitions of fields with spontaneously broken symmetry in the early Universe. Their existence finds support in modern superstrings theories, both in compactification models and in theories with extended additional dimensions. Strings can hold currents, effectively become electrically superconducting wires of astrophysical dimensions. Superconducting cosmic strings can serve as powerful sources of non-thermal radiation in wide energy range. Mechanisms of radiation are synchrotron, synchrotron self-Compton and inverse-Compton on CMB photons radiation of electrons accelerated by bow shock wave, created by magnetosphere of relativistically moving string in intergalactic medium (IGM). Expected fluxes of radiation from the shocked plasma around superconducting cosmic strings are calculated for strings with various tensions and for different cases of their location. Possibilities of strings detection by existing facilities are estimated.

  3. The Astrobiological Case for Our Cosmic Ancestry

    Science.gov (United States)

    Wickramasinghe, Chandra

    With steadily mounting evidence that points to a cosmic origin of terrestrial life, a cultural barrier prevails against admitting that such a connection exists. Astronomy continues to reveal the presence of organic molecules and organic dust on a huge cosmic scale, amounting to a third of interstellar carbon tied up in this form. Just as the overwhelming bulk of organics on Earth stored over geological timescales are derived from the degradation of living cells, so it seems most likely that interstellar organics in large measure also derive from biology. As we enter a new decade -- the year 2010 -- a clear pronouncement of our likely alien ancestry and of the existence of extraterrestrial life on a cosmic scale would seem to be overdue.

  4. Low cloud properties influenced by cosmic rays

    DEFF Research Database (Denmark)

    Marsh, Nigel; Svensmark, Henrik

    2000-01-01

    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 (less than or equal to3 ......), which points to a microphysical mechanism involving aerosol formation that is enhanced by ionization due to cosmic rays. If confirmed it suggests that the average state of the heliosphere is important for climate on Earth.......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 (less than or equal to3 km...

  5. Cosmic ray physics with the ALEPH detector

    CERN Document Server

    Besier, H; Kempa, J; Luitz, S; Maggi, M; Maier, D; Misiejuk, A; Müller, A S; Putzer, A; Rensch, B; Sander, H G; Schmeling, S; Schmelling, M; Schreiber, V; Wachsmuth, H W; Ziegler, T; Zuber, K

    2000-01-01

    ALEPH is one of the four detectors at the Large Electron-Positron Collider (LEP) at a depth of about 320 m.w.e. Its hadron calorimeter and scintillator arrays installed at distances up to about 1 km away from ALEPH are used to measure cosmic muon induced time coincidences over large distances. The aim of this experiment (CosmoALEPH) is (1) to study the muon component above 70 GeV of extensive air showers (EAS) and (2) to test the feasibility of searching for time correlations over even larger distances (up to 8 km) between the four LEP detectors. Layout and first results of CosmoALEPH are presented demonstrating the potential for cosmic ray physics in the LEP tunnel. The multiplicity distribution of muons in cosmic events recorded in ALEPH's tracking detector is presented. (28 refs).

  6. PRECISE COSMIC RAYS MEASUREMENTS WITH PAMELA

    Directory of Open Access Journals (Sweden)

    A. Bruno

    2013-12-01

    Full Text Available The PAMELA experiment was launched on board the Resurs-DK1 satellite on June 15th 2006. The apparatus was designed to conduct precision studies of charged cosmic radiation over a wide energy range, from tens of MeV up to several hundred GeV, with unprecedented statistics. In five years of continuous data taking in space, PAMELA accurately measured the energy spectra of cosmic ray antiprotons and positrons, as well as protons, electrons and light nuclei, sometimes providing data in unexplored energetic regions. These important results have shed new light in several astrophysical fields like: an indirect search for Dark Matter, a search for cosmological antimatter (anti-Helium, and the validation of acceleration, transport and secondary production models of cosmic rays in the Galaxy. Some of the most important items of Solar and Magnetospheric physics were also investigated. Here we present the most recent results obtained by the PAMELA experiment.

  7. Thirty-Year Periodicity of Cosmic Rays

    Directory of Open Access Journals (Sweden)

    Jorge Pérez-Peraza

    2012-01-01

    Full Text Available Cosmogenic isotopes have frequently been employed as proxies of ancient cosmic ray fluxes. On the basis of periodicities of the 10Be time series (using data from both the South and North Poles and the 14C time series (with data from Intercal-98, we offer evidence of the existence of cosmic ray fluctuations with a periodicity of around 30 years. Results were obtained by using the wavelet transformation spectral technique, signal reconstruction by autoregressive spectral analysis (ARMA, and the Lomb-Scargle periodogram method. This 30-year periodicity seems to be significant in nature because several solar and climatic indexes exhibit the same modulation, which may indicate that the 30-year frequency of cosmic rays is probably a modulator agent for terrestrial phenomena, reflecting the control source, namely, solar activity.

  8. Does electromagnetic radiation accelerate galactic cosmic rays

    Science.gov (United States)

    Eichler, D.

    1977-01-01

    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.

  9. Cosmic-Ray Observations with HAWC30

    Science.gov (United States)

    Fiorino, Daniel

    2013-04-01

    The High-Altitude Water Cherenkov (HAWC) Observatory is a TeV gamma-ray and cosmic-ray detector currently under construction at an altitude of 4100 meters on the slope of Volc'an Sierra Negra near Puebla, Mexico. HAWC is an extensive air-shower array comprising 300 optically-isolated water Cherenkov detectors. Each detector contains 200,000 liters of filtered water and four upward-facing photomultiplier tubes. Since September 2012, 30 water Cherenkov detectors have been instrumented and operated in data acquisition. With 10 percent of the detector complete and six months of operation, the event statistics are already sufficient to perform detailed studies of cosmic rays observed at the site. We will report on cosmic-ray observations with HAWC30, in particular the detection and study of the shadow of the moon. From these observations, we infer the pointing accuracy of the detector and our angular resolution of the detector reconstruction.

  10. Closed timelike geodesics in a gas of cosmic strings

    CERN Document Server

    Grøn, Ø; Gron, Oyvind; Johannesen, Steinar

    2007-01-01

    We find a class of solutions of Einstein's field equations representing spacetime outside a spinning cosmic string surrounded by a gas of non-spinning cosmic strings, and show that there exist closed timelike geodesics in this spacetime.

  11. A Cosmic Baby-Boom

    Science.gov (United States)

    2005-09-01

    Large Population of Galaxies Found in the Young Universe with ESO's VLT The Universe was a more fertile place soon after it was formed than has previously been suspected. A team of French and Italian astronomers [1] made indeed the surprising discovery of a large and unknown population of distant galaxies observed when the Universe was only 10 to 30% its present age. ESO PR Photo 29a/05 ESO PR Photo 29a/05 New Population of Distant Galaxies [Preview - JPEG: 400 x 424 pix - 191k] [Normal - JPEG: 800 x 847 pix - 449k] [HiRes - JPEG: 2269 x 2402 pix - 2.0M] ESO PR Photo 29b/05 ESO PR Photo 29b/05 Average Spectra of Distant Galaxies [Preview - JPEG: 400 x 506 pix - 141k] [Normal - JPEG: 800 x 1012 pix - 320k] This breakthrough is based on observations made with the Visible Multi-Object Spectrograph (VIMOS) as part of the VIMOS VLT Deep Survey (VVDS). The VVDS started early 2002 on Melipal, one of the 8.2-m telescopes of ESO's Very Large Telescope Array [2]. In a total sample of about 8,000 galaxies selected only on the basis of their observed brightness in red light, almost 1,000 bright and vigorously star forming galaxies were discovered that were formed between 9 and 12 billion years ago (i.e. about 1,500 to 4,500 million years after the Big Bang). "To our surprise, says Olivier Le Fèvre, from the Laboratoire d'Astrophysique de Marseille (France) and co-leader of the VVDS project, "this is two to six times higher than had been found previously. These galaxies had been missed because previous surveys had selected objects in a much more restrictive manner than we did. And they did so to accommodate the much lower efficiency of the previous generation of instruments." While observations and models have consistently indicated that the Universe had not yet formed many stars in the first billion years of cosmic time, the discovery announced today by scientists calls for a significant change in this picture. The astronomers indeed find that stars formed two to three times

  12. Kriging interpolating cosmic velocity field

    Science.gov (United States)

    Yu, Yu; Zhang, Jun; Jing, Yipeng; Zhang, Pengjie

    2015-10-01

    Volume-weighted statistics of large-scale peculiar velocity is preferred by peculiar velocity cosmology, since it is free of the uncertainties of galaxy density bias entangled in observed number density-weighted statistics. However, measuring the volume-weighted velocity statistics from galaxy (halo/simulation particle) velocity data is challenging. Therefore, the exploration of velocity assignment methods with well-controlled sampling artifacts is of great importance. For the first time, we apply the Kriging interpolation to obtain the volume-weighted velocity field. Kriging is a minimum variance estimator. It predicts the most likely velocity for each place based on the velocity at other places. We test the performance of Kriging quantified by the E-mode velocity power spectrum from simulations. Dependences on the variogram prior used in Kriging, the number nk of the nearby particles to interpolate, and the density nP of the observed sample are investigated. First, we find that Kriging induces 1% and 3% systematics at k ˜0.1 h Mpc-1 when nP˜6 ×1 0-2(h-1 Mpc )-3 and nP˜6 ×1 0-3(h-1 Mpc )-3 , respectively. The deviation increases for decreasing nP and increasing k . When nP≲6 ×1 0-4(h-1 Mpc )-3 , a smoothing effect dominates small scales, causing significant underestimation of the velocity power spectrum. Second, increasing nk helps to recover small-scale power. However, for nP≲6 ×1 0-4(h-1 Mpc )-3 cases, the recovery is limited. Finally, Kriging is more sensitive to the variogram prior for a lower sample density. The most straightforward application of Kriging on the cosmic velocity field does not show obvious advantages over the nearest-particle method [Y. Zheng, P. Zhang, Y. Jing, W. Lin, and J. Pan, Phys. Rev. D 88, 103510 (2013)] and could not be directly applied to cosmology so far. However, whether potential improvements may be achieved by more delicate versions of Kriging is worth further investigation.

  13. Plasma effects on extragalactic ultra-high-energy cosmic ray hadron beams in cosmic voids

    Energy Technology Data Exchange (ETDEWEB)

    Krakau, Steffen; Schlickeiser, Reinhard [Institut fur Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum (Germany)

    2015-05-01

    The linear instability of an ultrarelativistic hadron beam (Γ{sub b} ∼ 10{sup 6}) in the unmagnetized intergalactic medium is investigated with respect to the excitation of collective electrostatic and aperiodic electromagnetic fluctuations. This analysis is important for the propagation of extragalactic ultrarelativistic cosmic rays (E > 10{sup 15} eV) from their distant sources to Earth. We calculate minimum instability growth times which are orders of magnitude shorter than the cosmic ray propagation time in the IGM. Due to nonlinear effects, especially the modulation instability, the cosmic ray beam stabilize and can propagate with nearly no energy loss through the intergalactic medium.

  14. Thin shells joining local cosmic string geometries

    Energy Technology Data Exchange (ETDEWEB)

    Eiroa, Ernesto F. [Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Rubin de Celis, Emilio; Simeone, Claudio [Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Ciudad Universitaria Pabellon I, IFIBA-CONICET, Buenos Aires (Argentina)

    2016-10-15

    In this article we present a theoretical construction of spacetimes with a thin shell that joins two different local cosmic string geometries. We study two types of global manifolds, one representing spacetimes with a thin shell surrounding a cosmic string or an empty region with Minkowski metric, and the other corresponding to wormholes which are not symmetric across the throat located at the shell. We analyze the stability of the static configurations under perturbations preserving the cylindrical symmetry. For both types of geometries we find that the static configurations can be stable for suitable values of the parameters. (orig.)

  15. Cosmic multimuon bundles detected by DELPHI

    CERN Document Server

    Rídky, J

    2004-01-01

    The DELPHI detector located at LEP accelerator has been used also to measure multimuon bundles originated from cosmic ray interactions. Two subdetectors-hadron calorimeter and time projection chamber, are used for this purpose. The 1999 and 2000 data are analyzed over wide range of multiplicities. The multiplicity distribution is compared with prediction of Monte Carlo simulation based on CORSIKA/QGSJET. The Monte-Carlo does not describe the large multiplicity part of data. Even the extreme assumption on the cosmic ray composition (pure iron nuclei) hardly predicts comparable number of high-multiplicity events.

  16. Cosmic ray effects in microcalorimeter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Stahle, C.K. E-mail: cak@lheapop.gsfc.nasa.gov; Boyce, K.R.; Brown, G.V.; Cottam, J.; Figueroa-Feliciano, E.; Galeazzi, M.; Kelley, R.L.; McCammon, D.; Porter, F.S.; Szymkowiak, A.E.; Tillotson, W.A

    2004-03-11

    We have identified signals resulting from cosmic rays and environmental gamma rays depositing energy in the pixels and in the silicon frame of the Astro-E2/X-Ray Spectrometer microcalorimeter array. Coincidences between pixels and between the array and an anti-coincidence detector determined the nature of the events. Pulse shapes and amplitudes from the cosmic ray events helped refine the thermal model of the array chip. We discuss how future arrays can be optimized either for the greatest background rejection or for the highest source count rates.

  17. Cosmic Rays: studies and measurements before 1912

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, Alessandro [INFN and Università di Udine, Via delle Scienze 206, I-33100 Udine (Italy); LIP/IST Lisboa (Portugal)

    2013-06-15

    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.

  18. Cosmic rays from trans-relativistic supernovae

    CERN Document Server

    Budnik, R; MacFadyen, A; Waxman, E

    2007-01-01

    We derive constraints which must be satisfied by the sources of ~10^{15} to ~10^{18} eV cosmic rays, under the assumption that the sources are Galactic. We show that while these constraints are not satisfied by ordinary supernovae, which are believed to be the sources of 10^{-2}, of the explosion energy in mildly relativistic, \\gamma\\beta>1, ejecta. Galactic TRSNe may therefore be the sources of cosmic rays with energies up to ~10^{18} eV.

  19. Wave diffraction by a cosmic string

    CERN Document Server

    Fernández-Núñez, Isabel

    2016-01-01

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects.

  20. Cosmic Time Machines: the Causality Issue

    Directory of Open Access Journals (Sweden)

    Felice Fernando de

    2013-09-01

    Full Text Available Continued gravitational collapse gives rise to curvature singularities. If a curvature singularity is globally naked then the space-time may be causally future illbehaved admitting closed time-like or null curves which extend to asymptotic distances and generate a Cosmic Time Machine (de Felice (1995 Lecture Notes in Physics 455, 99 [6]. The existence of Cosmic Time Machines makes it plausible the violation of causality. I conjecture that this circumstance is prevented by some, yet unknown, physical process and show that such a mechanism indeed exists in the Kerr spacetime.

  1. Cosmic Origins Program Annual Technology Report

    Science.gov (United States)

    Pham, Bruce Thai; Neff, Susan Gale

    2016-01-01

    What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time.

  2. Wave diffraction by a cosmic string

    Science.gov (United States)

    Fernández-Núñez, Isabel; Bulashenko, Oleg

    2016-08-01

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects.

  3. The Reionization of Cosmic Hydrogen by the First Galaxies

    Science.gov (United States)

    Loeb, Abraham

    Cosmology is by now a mature experimental science. We are privileged to live at a time when the story of genesis (how the Universe started and developed) can be critically explored by direct observations. Looking deep into the Universe through powerful telescopes, we can see images of the Universe when it was younger because of the finite time it takes for light to travel to us from distant sources. Existing data sets include an image of the Universe when it was 0.4 million years old (in the form of the cosmic microwave background), as well as images of individual galaxies when the Universe was older than a billion years. But there is a serious challenge: in between these two epochs was a period when the Universe was dark, stars had not yet formed, and the cosmic microwave background no longer traced the distribution of matter. And this is precisely the most interesting period, when the primordial soup evolved into the rich zoo of objects we now see. The observers are moving ahead along several fronts. The first involves the construction of large infrared telescopes on the ground and in space, that will provide us with new photos of the first galaxies. Current plans include ground-based telescopes which are 24-42 m in diameter, and NASA's successor to the Hubble Space Telescope, called the James Webb Space Telescope. In addition, several observational groups around the globe are constructing radio arrays that will be capable of mapping the three-dimensional distribution of cosmic hydrogen in the infant Universe. These arrays are aiming to detect the long-wavelength (redshifted 21 cm) radio emission from hydrogen atoms. The images from these antenna arrays will reveal how the non-uniform distribution of neutral hydrogen evolved with cosmic time and eventually was extinguished by the ultraviolet radiation from the first galaxies. Theoretical research has focused in recent years on predicting the expected signals for the above instruments and motivating these

  4. Search for Cosmic Strings in the GOODS Survey

    CERN Document Server

    Christiansen, J L; James, K A; Goldman, J; Maruyama, D; Smoot, G F

    2008-01-01

    We search Hubble Space Telescope Treasury Program images collected as part of the Great Observatories Origins Deep Survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. Our technique includes estimates of the efficiency for finding the lensed galaxy pair. In the North (South) survey field we find no evidence out to a redshift of greater than 1 (0.5) for cosmic strings to a mass per unit length limit of $G\\mu<3.0x10^{-7}$ at 95% CL. In the combined 314.9 arcmin$^2$ of the North and South survey fields this corresponds to a limit on $\\Omega_{strings}<0.0056$. Our global limit on $G\\mu$ is more than an order of magnitude lower than searches for individual strings in CMB data. Our limit is higher than other CMB and gravitational wave searches, however we note that it is less model dependent than these other searches.

  5. Cosmic Evolution of Long Gamma-Ray Burst Luminosity

    CERN Document Server

    Deng, Can-Min; Guo, Bei-Bei; Lu, Rui-Jing; Wang, Yuan-Zhu; Wei, Jun-Jie; Wu, Xue-Feng; Liang, En-Wei

    2016-01-01

    The cosmic evolution of gamma-ray burst (GRB) luminosity is essential for revealing the GRB physics and for using GRBs as cosmological probes. We investigate the luminosity evolution of long GRBs with a large sample of 258 {\\em Swift}/BAT GRBs. Parameterized the peak luminosity of individual GRBs evolves as $L_{\\rm p}\\propto{\\rm }(1+z)^{k}$, we get $k=1.49\\pm0.19$ using the non-parametric $\\tau$ statistics method without considering observational biases of GRB trigger and redshift measurement. By modeling these biases with the observed peak flux and characterizing the peak luminosity function of long GRBs as a smoothly broken power-law with a break that evolves as $L_{\\rm b}\\propto (1+z)^{k_{\\rm b}}$, we obtain $k_{\\rm b}=1.14^{+0.99}_{-0.47}$ through simulations based on assumption that the long GRB rate follows the star formation rate (SFR) incorporating with cosmic metallicity history. The derived $k$ and $k_b$ values are systematically smaller than that reported in previous papers. By removing the observa...

  6. Energy spectra of cosmic-ray nuclei at high energies

    CERN Document Server

    Ahn, H S; Bagliesi, M G; Barbier, L; Beatty, J J; Bigongiari, G; Brandt, T J; Childers, J T; Conklin, N B; Coutu, S; DuVernois, M A; Ganel, O; Han, J H; Jeon, J A; Kim, K C; Lee, M H; Maestro, P; Malinine, A; Marrocchesi, P S; Minnick, S; Mognet, S I; Nam, S W; Nutter, S; Park, I H; Park, N H; Seo, E S; Sina, R; Walpole, P; Wu, J; Yang, J; Yoon, Y S; Zei, R; Zinn, S Y

    2009-01-01

    We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic Ray Energetics And Mass (CREAM). The instrument included different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to $\\sim 10^{14}$ eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an $E^{-2.66 \\pm 0.04}$ power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/$n$ energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be $0.080 \\pm 0.025 $(stat.)$ \\pm 0.025 $(sys.) at $\\sim $800 GeV/$n$, in good agreement with a recent result from the first CREAM flight.

  7. Computation of cosmic radiation spectra and application to aircrew dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Song Jae

    2002-02-15

    Using the Monte Carlo radiation transport code FLUKA- 99, secondary cosmic radiation energy spectra and intensities of neutrons, protons, photons, electrons, and muons were calculated for different geographical latitude and longitude at the commercial jet's altitudes ranging from 27000 ft to 41000 ft. The Badhwar's proton model was used to construct the primary cosmic radiation spectrum and effect of the vertical cutoff rigidity was considered after spectra similar to those given in literature were resulted. By applying the effective dose conversion factors, a calculation tool for aircrew doses was developed. According to the resulting dose rate distribution, effective dose rate over North pole region is around three times of that over equator region due to the geomagnetical shielding effect. Illustrative assessments of aircrew doses were made for four distinctive routes of Korean airliners : Seoul - New York (USA), London (UK), Sydney (Australia) and Mumbai(India). The effective doses to aircrew incurred from a round trip were 0.047, 0.055, 0.018, and 0.018{mu}Sv, respectively. If aircrew work 500 hour s a year at the cruise altitude of a international airline, the individual dose would reach 2 mSv which is about the same size as the average annual dose of workers at a nuclear power plant.

  8. Cosmological fast radio bursts as a cosmic ruler?

    CERN Document Server

    Zhou, Bei; Wang, Tao; Fan, Yi-Zhong; Wei, Da-Ming

    2014-01-01

    We discuss the possibility of using cosmological fast radio bursts (FRBs) as a viable cosmic ruler. We find out that the contribution of the host galaxies to the detected dispersion measures may be ignorable for the FRBs not from galaxy centers or star forming regions. The inhomogeneity of the intergalactic medium (IGM), however, causes significant deviation of the dispersion measure from that predicted in the simplified homogeneous IGM model for individual event. Fortunately, with sufficient FRBs along different sightlines but within a very narrow redshift interval (e.g., $\\Delta z \\sim 0.05$), the mean from averaging observed dispersion measures does not suffer such a problem and hence may be used as a cosmic ruler. We show that in the optimistic case (e.g., tens FRBs in each $\\Delta z$ have been measured; the most distant FRBs were at redshift $\\geq 3$; the host galaxies and the FRB sources contribute little to the detected dispersion measures), FRBs could help constrain the equation of state of dark energ...

  9. Cosmic Ballet or Devil's Mask?

    Science.gov (United States)

    2004-04-01

    Stars like our Sun are members of galaxies, and most galaxies are themselves members of clusters of galaxies. In these, they move around among each other in a mostly slow and graceful ballet. But every now and then, two or more of the members may get too close for comfort - the movements become hectic, sometimes indeed dramatic, as when galaxies end up colliding. ESO PR Photo 12/04 shows an example of such a cosmic tango. This is the superb triple system NGC 6769-71, located in the southern Pavo constellation (the Peacock) at a distance of 190 million light-years. This composite image was obtained on April 1, 2004, the day of the Fifth Anniversary of ESO's Very Large Telescope (VLT). It was taken in the imaging mode of the VIsible Multi-Object Spectrograph (VIMOS) on Melipal, one of the four 8.2-m Unit Telescopes of the VLT at the Paranal Observatory (Chile). The two upper galaxies, NGC 6769 (upper right) and NGC 6770 (upper left), are of equal brightness and size, while NGC 6771 (below) is about half as bright and slightly smaller. All three galaxies possess a central bulge of similar brightness. They consist of elderly, reddish stars and that of NGC 6771 is remarkable for its "boxy" shape, a rare occurrence among galaxies. Gravitational interaction in a small galaxy group NGC 6769 is a spiral galaxy with very tightly wound spiral arms, while NGC 6770 has two major spiral arms, one of which is rather straight and points towards the outer disc of NGC 6769. NGC 6770 is also peculiar in that it presents two comparatively straight dark lanes and a fainter arc that curves towards the third galaxy, NGC 6771 (below). It is also obvious from this new VLT photo that stars and gas have been stripped off NGC 6769 and NGC 6770, starting to form a common envelope around them, in the shape of a Devil's Mask. There is also a weak hint of a tenuous bridge between NGC 6769 and NGC 6771. All of these features testify to strong gravitational interaction between the three galaxies

  10. Propagation of cosmic rays in the Earth's atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Putze, Antje [LPSC-CNRS-IN2P3, 53, avenue des Martyrs, 38021 Grenoble cedex (France)

    2006-06-15

    Cosmic rays are composed of charged particles, which arrive after a long travel through the Galaxy on Earth. Supernova explosions are considered to be galactic sources, which accelerate these particles up to energies around 10{sup 18} eV. Beyond this energy, one supposes that the extragalactic sources, like active galaxy nuclei (AGN), gamma ray bursts or pulsars, are the origin of the ultra high energy cosmic rays. The spectral index of the elemental energy distributions of cosmic rays reflects the dynamic of its propagation, particularly the conjugation of the effects connected to the cosmic ray source spectrum and those connected to its propagation (acceleration, absorption and escape). The evolution of the spectral index with the cosmic-ray particle energy constitutes a sensitive test of the components, which determine this evolution. The precise index measurement of individual elemental spectra of the cosmic rays by AMS up to TeV and by the experiment CREAM beyond it, from TeV to PeV, will permit to proceed in this problematic. One of the difficulties on this measurement is to take well into account the systematic errors. During the data analysis we have to take into account in particular the interaction (diffusion and fragmentation) of the ions while their travel through the Earth's atmosphere. The study of the interaction and the fragmentation of these ions in the atmosphere is hence indispensable and described in this work. The study is based on a matrix calculation, which had been successfully implemented and tested and which has permitted to analyse the effects, caused by the experimental uncertainties on the cross sections, on the spectral index measurement. (author)

  11. Ultrahigh Energy Cosmic Rays: New Physics or Old Physics?

    CERN Document Server

    Stecker, F W

    2004-01-01

    We consider the advantages of and the problems associated with hypotheses to explain the origin of ulthrahigh energy cosmic rays (UHECR: E > 10 EeV) and the "trans GZK" cosmic rays (TGZK: E > 100 EeV), both through "old physics" (acceleration in cosmic sources) and "new physics" (new particles, topological defects, fat neutrino cross sections, Lorentz invariance violation).

  12. Impact of Cosmic Ray Transport on Galactic Winds

    Science.gov (United States)

    Farber, Ryan; Ruszkowski, Mateusz; Yang, Hsiang-Yi Karen; Gould Zweibel, Ellen

    2017-08-01

    Despite playing a fundamental role in galaxy evolution, the physical mechanisms responsible for driving galactic winds remain unclear. The role of cosmic rays generated by supernovae and young stars has very recently begun to receive significant attention due to the realization that cosmic rays can efficiently accelerate galactic winds. Microscopic cosmic ray transport processes are fundamental for determining the efficiency of cosmic ray wind driving. Previous studies focused on modeling of cosmic ray transport either via constant diffusion coefficient or via streaming proportional to the Alfv{é}n speed. However, in predominantly neutral gas, cosmic rays can propagate faster than in the ionized medium and the effective transport can be substantially larger, i.e., cosmic rays are decoupled from the gas. We perform three-dimensional magneto-hydrodynamical simulations of patches of galactic disks including the effects of cosmic rays. Our simulations include the decoupling of cosmic rays in the neutral ISM phases. We find that, compared to the ordinary diffusive cosmic ray transport case, accounting for the decoupling leads to significantly different wind properties such as the cosmic ray spatial distribution, wind speed, density, and temperature. These results have implications for the magnetization of the circumgalactic medium and the pollution of the circumgalactic medium with cosmic rays.

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

    Science.gov (United States)

    Barghouty, A. F.

    2009-01-01

    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.

  14. Re-evaluation of cosmic ray cutoff terminology

    Science.gov (United States)

    Cooke, D. J.; Humble, J. E.; Shea, M. A.; Smart, D. F.; Lund, N.; Rasmussen, I. L.; Byrnak, B.; Goret, P.; Petrou, N.

    1985-01-01

    The study of cosmic ray access to locations inside the geomagnetic field has evolved in a manner that has led to some misunderstanding and misapplication of the terminology originally developed to describe particle access. This paper presents what is believed to be a useful set of definitions for cosmic ray cutoff terminology for use in theoretical and experimental cosmic ray studies.

  15. ISO sees the pattern in the cosmic wallpaper

    Science.gov (United States)

    1998-07-01

    Two dozen distant galaxies that are undergoing a process of intense evolution --either merging to build larger ones or reaching their final shape-- have been detected by a team of French astronomers using the European Space Agency's ISO space telescope. These are the first individual objects known to contribute their energy to the bulk of the Cosmic Infrared Background, a radiation that fills the entire universe like a wallpaper, emitted at the era when galaxies were formed. The new-found distant galaxies are indeed like the 'pattern' in this 'cosmic wallpaper'. This discovery will for the first time enable scientists to test different theories of galaxy formation, and therefore to tackle a key problem of astronomy --the birth process of galaxies which has remained a mystery so far, mainly because current telescopes cannot reach that far back in time, about 12,000 million years ago. This obstacle has been partially overcome by the French team headed by Jean-Loup Puget, at the Institut d'Astrophysique Spatiale in Paris, precisely because they searched for the primeval galaxies by focusing first on the study of the cosmic wallpaper, the 'Cosmic Infrared Background' (see note to editors below). This background glow that fills the whole universe is a by-product of the galaxy formation itself, a relic of the era when the first galaxies were being born. Its existence was predicted three decades ago and it was known to be detectable only at infrared wavelengths, as the dust enshrouding young galaxies causes them to be both opaque in visible light but bright at infrared wavelengths. However, this cosmic wallpaper turned out to be very dim: only two years ago Puget's team detected it after a careful analysis of data from NASA's COBE satellite. Once the 'Cosmic Infrared Background' had been found, the next step was to disentangle it into the sources contributing to it, that is, into the young galaxies in evolution or the 'pattern' in the wallpaper. The two dozen distant

  16. Scientific results from the cosmic background explorer (COBE). [Information on cosmic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C.L.; Boggess, N.W.; Cheng, E.S.; Hauser, M.G.; Kelsall, T.; Mather, J.C.; Moseley, S.H. Jr.; Shafer, R.A.; Silverberg, R.F. (NASA/Goddard Space Flight Center, Greenbelt, MD (United States)); Murdock, T.L. (General Research Corp., Danvers, MA (United States)); Smoot, G.F. (Lawrence Berkeley Lab., CA (United States)); Weiss, R. (Massachusetts Inst. of Technology, Cambridge (United States)); Wright, E.L. (Univ. of California, Los Angeles (United States))

    1993-06-01

    The National Aeronautics and Space Administration (NASA) has flown the COBE satellite to observe the Big Bang and the subsequent formation of galaxies and large-scale structure. Data from the Far-Infrared Absolute Spectrophotometer (FIRAS) show that the spectrum of the cosmic microwave background is that of a black body of temperature T = 2.73 [+-] 0.06 K, with no deviation from a black-body spectrum greater than 0.25% of the peak brightness. The data from the Differential Microwave Radiometers (DMR) show statistically significant cosmic microwave background anisotropy, consistent with a scale-invariant primordial density fluctuation spectrum. Measurements from the Diffuse Infrared Background Experiment (DIRBE) provide new conservation upper limits to the cosmic infrared background. Extensive modeling of solar system and galactic infrared foregrounds is required for further improvement in the cosmic infrared background limits. 104 refs., 1 tab.

  17. Inflation Fossils in Cosmic Structure

    Science.gov (United States)

    Kamionkowski, Marc

    The agreement of the predictions of inflation with increasingly precise cosmic microwave background (CMB) and large-scale-structure (LSS) data is remarkable. The notion that such a simple early-Universe scenario, based on still-mysterious ultra-high-energy physics, can explain such a wealth of precise data is simply amazing. An active ongoing program of research is afoot to seek the CMB polarization signatures of inflationary gravitational waves and measure the primordial bispectrum in order to learn about inflation. Still, there is far more that can be done to probe inflationary physics, and no stone should be left unturned in this quest. Here we propose a multi-component program of theoretical research that includes model building, new CMB/LSS tests, a potentially powerful new survey strategy, and the investigation of a new observational avenue for large-scale structure. We propose to broaden the circle of ideas to empirically probe inflation. To begin, the hemispherical power asymmetry seen in WMAP and Planck is truly striking. While it may simply be an unusual statistical fluke, a more tantalizing possibility is that it is a remnant of the pre-inflationary Universe. We propose to develop and study several physical models for this asymmetry and work out other testable predictions of these models. Only by pursuing other signatures of whatever new physics may be responsible for this asymmetry will we be able to infer if it is truly a window to new physics. We also plan to develop departures from statistical isotropy (SI) as a test of inflationary models. We have recently shown that single-field slow-roll inflation generically predicts a quadrupolar departure from SI in primordial perturbations, albeit a very small one. The power quadrupole is expected, however, to be significantly larger in more general inflationary models. We propose to calculate these power quadrupoles so that new constraints to the power quadrupole from CMB and LSS data can be applied to test

  18. Search for Antihelium in the Cosmic Radiation

    DEFF Research Database (Denmark)

    Streitmatter, R.E.; Barbier, L.M.; Christian, E.R.;

    1996-01-01

    The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba Canada on July 16-17, 1992. Sixteen hours of data were taken. Measurements of multiple dE/dX, rigidity, and time of flight were used to search for antihelium in the cosmic radiation. A report on the r...

  19. Alpha Shape Topology of the Cosmic Web

    NARCIS (Netherlands)

    Weygaert, Rien van de; Platen, Erwin; Vegter, Gert; Eldering, Bob; Kruithof, Nico

    2010-01-01

    We study the topology of the Megaparsec Cosmic Web on the basis of the Alpha Shapes of the galaxy distribution. The simplicial complexes of the alpha shapes are used to determine the set of Betti numbers (βk, k = 1, . . . , D), which represent a complete characterization of the topology of a manifol

  20. The Sticky Geometry of the Cosmic Web

    NARCIS (Netherlands)

    Hidding, Johan; Weygaert, Rien van de; Vegter, Gert; Jones, Bernard J.T.; Teillaud, Monique

    2012-01-01

    In this video we highlight the application of Computational Geometry to our understanding of the formation and dynamics of the Cosmic Web. The emergence of this intricate and pervasive weblike structure of the Universe on Megaparsec scales can be approximated by a well-known equation from fluid mech

  1. Consistency relation for cosmic magnetic fields

    DEFF Research Database (Denmark)

    Jain, R. K.; Sloth, M. S.

    2012-01-01

    to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields. DOI...

  2. Cosmic emergy based ecological systems modelling

    Science.gov (United States)

    Chen, H.; Chen, G. Q.; Ji, X.

    2010-09-01

    Ecological systems modelling based on the unified biophysical measure of cosmic emergy in terms of embodied cosmic exergy is illustrated in this paper with ecological accounting, simulation and scenario analysis, by a case study for the regional socio-economic ecosystem associated with the municipality of Beijing. An urbanized regional ecosystem model with eight subsystems of natural support, agriculture, urban production, population, finance, land area, potential environmental impact, and culture is representatively presented in exergy circuit language with 12 state variables governing by corresponding ecodynamic equations, and 60 flows and auxiliary variables. To characterize the regional socio-economy as an ecosystem, a series of ecological indicators based on cosmic emergy are devised. For a systematic ecological account, cosmic exergy transformities are provided for various dimensions including climate flows, natural resources, industrial products, cultural products, population with educational hierarchy, and environmental emissions. For the urban ecosystem of Beijing in the period from 1990 to 2005, ecological accounting is carried out and characterized in full details. Taking 2000 as the starting point, systems modelling is realized to predict the urban evolution in a one hundred time horizon. For systems regulation, scenario analyses with essential policy-making implications are made to illustrate the long term systems effects of the expected water diversion and rise in energy price.

  3. A database of charged cosmic rays

    Science.gov (United States)

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

    2014-09-01

    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

  4. Nuclear War from a Cosmic Perspective

    CERN Document Server

    Tegmark, Max

    2015-01-01

    I discuss the impact of computer progress on nuclear war policy, both by enabling more accurate nuclear winter simulations and by affecting the probability of war starting accidentally. I argue that from a cosmic perspective, humanity's track record of risk mitigation is inexcusably pathetic, jeopardizing the potential for life to flourish for billions of years.

  5. Cosmic Rays Accelerated at Cosmological Shock Waves

    Indian Academy of Sciences (India)

    Renyi Ma; Dongsu Ryu; Hyesung Kang

    2011-03-01

    Based on hydrodynamic numerical simulations and diffusive shock acceleration model, we calculated the ratio of cosmic ray (CR) to thermal energy. We found that the CR fraction can be less than ∼ 0.1 in the intracluster medium, while it would be of order unity in the warm-hot intergalactic medium.

  6. Higher Dimensional Radiation Collapse and Cosmic Censorship

    CERN Document Server

    Ghosh, S G

    2000-01-01

    We study the occurrence of naked singularities in the spherically symmetric collapse of radiation shells in a higher dimensional spacetime. The necessary conditions for the formation of a naked singularity or a black hole are obtained. The naked singularities are found to be strong in the Tipler's sense and thus violating cosmic censorship conjecture.

  7. Search for cosmic neutrinos with ANTARES

    NARCIS (Netherlands)

    Bogazzi, Claudio

    2014-01-01

    A time integrated search for cosmic neutrinos is discussed in this thesis using four years of data collected by the ANTARES experiment. No statistically significant signal was found, therefore upper limits on the neutrino flux were derived. Limits for specific models of RX J1713.7-3946, Vela X and C

  8. Cosmic Ray Origin, Acceleration and Propagation

    CERN Document Server

    Baring, M G

    1999-01-01

    This paper summarizes highlights of the OG3.1, 3.2 and 3.3 sessions of the XXVIth International Cosmic Ray Conference in Salt Lake City, which were devoted to issues of origin/composition, acceleration and propagation.

  9. Cosmological constant influence on cosmic string spacetime

    CERN Document Server

    Abbassi, Amir H; 10.1103/physRevD.67.103504

    2008-01-01

    We investigate the line element of spacetime around a linear cosmic string in the presence of a cosmological constant. We obtain the metric and argue that it should be discarded because of asymptotic considerations. Then a time dependent and consistent form of the metric is obtained and its properties are discussed.

  10. Quasar Mass Functions Across Cosmic Time

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2010-01-01

    I present mass functions of actively accreting black holes detected in different quasar surveys which in concert cover a wide range of cosmic history. I briefly address what we learn from these mass functions. I summarize the motivation for such a study and the methods by which we determine black...

  11. Cosmic Time Transformations in Cosmological Relativity

    CERN Document Server

    Oliveira, Firmin J

    2015-01-01

    The relativity of cosmic time is developed within the framework of Cosmological Relativity in five dimensions of space, time and velocity. The general and special theories are briefly described. Relations are obtained for mass density, cosmic time addition, cosmological redshift and luminosity distance. The model is applied to magnitude distance and light curve data from Type Ia supernovae and to simulated quasar like light curve power spectra. For cosmic time $t$, Hubble-Carmeli time constant $\\tau$, redshift $z$ and distance $r$, the luminosity distance relation $D_L=r(1+z)/\\sqrt{1-t^2/\\tau^2}$ is used to fit distance moduli from the Supernova Cosmology Project Union 2.1 data set, from which a value of $0.115$ is obtained for the matter density parameter. Assuming a baryon density of $0.038$, a rest mass energy of $0.99$ GeV is predicted for the $Y$ and the $\\Phi$ particles which comprise the hypothetical $X$ particle. In addition, the model's cosmic aging function $g1 = ( 1 + z) ( 1 - t^2 / \\tau^2 )$ has a...

  12. CosmicPy: Interactive cosmology computations

    Science.gov (United States)

    Lanusse, Francois; Rassat, Anais; Starck, Jean-Luc

    2016-01-01

    CosmicPy performs simple and interactive cosmology computations for forecasting cosmological parameters constraints; it computes tomographic and 3D Spherical Fourier-Bessel power spectra as well as Fisher matrices for galaxy clustering. Written in Python, it relies on a fast C++ implementation of Fourier-Bessel related computations, and requires NumPy, SciPy, and Matplotlib.

  13. Search for cosmic neutrinos with ANTARES

    NARCIS (Netherlands)

    Bogazzi, Claudio

    2014-01-01

    A time integrated search for cosmic neutrinos is discussed in this thesis using four years of data collected by the ANTARES experiment. No statistically significant signal was found, therefore upper limits on the neutrino flux were derived. Limits for specific models of RX J1713.7-3946, Vela X and

  14. Cosmic ray propagation with CRPropa 3

    Science.gov (United States)

    Alves Batista, R.; Erdmann, M.; Evoli, C.; Kampert, K.-H.; Kuempel, D.; Mueller, G.; Sigl, G.; Van Vliet, A.; Walz, D.; Winchen, T.

    2015-05-01

    Solving the question of the origin of ultra-high energy cosmic rays (UHECRs) requires the development of detailed simulation tools in order to interpret the experimental data and draw conclusions on the UHECR universe. CRPropa is a public Monte Carlo code for the galactic and extragalactic propagation of cosmic ray nuclei above ∼ 1017 eV, as well as their photon and neutrino secondaries. In this contribution the new algorithms and features of CRPropa 3, the next major release, are presented. CRPropa 3 introduces time-dependent scenarios to include cosmic evolution in the presence of cosmic ray deflections in magnetic fields. The usage of high resolution magnetic fields is facilitated by shared memory parallelism, modulated fields and fields with heterogeneous resolution. Galactic propagation is enabled through the implementation of galactic magnetic field models, as well as an efficient forward propagation technique through transformation matrices. To make use of the large Python ecosystem in astrophysics CRPropa 3 can be steered and extended in Python.

  15. Molecular Clouds as Cosmic-Ray Barometers

    CERN Document Server

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

    2009-01-01

    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...

  16. Goldstone Bosons as Fractional Cosmic Neutrinos

    CERN Document Server

    Weinberg, Steven

    2013-01-01

    It is suggested that Goldstone bosons may be masquerading as fractional cosmic neutrinos, contributing about 0.39 to what is reported as the effective number of neutrino types in the era before recombination. The broken symmetry associated with these Goldstone bosons is further speculated to be the conservation of the particles of dark matter.

  17. Multiscale phenomenology of the cosmic web

    NARCIS (Netherlands)

    Aragón-Calvo, Miguel A.; van de Weygaert, Rien; Jones, Bernard J. T.

    2010-01-01

    We analyse the structure and connectivity of the distinct morphologies that define the cosmic web. With the help of our multiscale morphology filter (MMF), we dissect the matter distribution of a cosmological Lambda cold dark matter N-body computer simulation into cluster, filaments and walls. The M

  18. Can one measure the Cosmic Neutrino Background?

    CERN Document Server

    Faessler, Amand; Kovalenko, Sergey; Simkovic, Fedor

    2016-01-01

    The Cosmic Microwave Background (CMB) yields information about our Universe at around 380 000 years after the Big Bang (BB). Due to the weak interaction of the neutrinos with matter the Cosmic Neutrino Background (CNB) should give information about a much earlier time of our Universe, around one second after the Big Bang. Probably the most promising method to `see' the Cosmic Neutrino Background is the capture of the electron neutrinos from the Background by Tritium, which then decays into 3He and an electron with the energy of the the Q-value = 18.562 keV plus the electron neutrino rest mass. The `KArlsruhe TRItium Neutrino' (KATRIN) experiment, which is in preparation, seems presently the most sensitive proposed method for measuring the electron antineutrino mass. At the same time KATRIN can also look by the reaction: electron neutrino (~1.95 Kelvin) + 3H --> 3He + e- (with the energy Q = 18.6 keV + electron neutrino mass). The capture of the Cosmic Background Neutrinos (CNB) should show in the electron spe...

  19. Cosmic ray muons in the deep ocean

    Science.gov (United States)

    Dumand Collaboration; Babson, J.; Barish, B.; Becker-Szenzy, R.; Bradner, H.; Cady, R.; Clem, J.; Dye, S.; Gaidos, J.; Gorham, P.; Grieder, P.; Kitamura, T.; Kropp, W.; Learned, J.; Matsuno, S.; March, R.; Mitsui, K.; O'Conner, D.; Ohashi, Y.; Okada, A.; Peterson, V.; Price, L.; Reines, F.; Roberts, A.; Roos, C.; Sobel, H.; Stenger, V.; Webster, M.; Wilson, C.

    1990-03-01

    A measurement of cosmic ray muon flux was obtained at ocean depths ranging from 2 km to 4 km at 500 m intervals off the West Coast of the Big Island of Hawaii. A brief description of the experiment and the results will be presented in this paper.

  20. Cosmic ray muons in the deep ocean

    Energy Technology Data Exchange (ETDEWEB)

    Babson, J.; Becker-Szenzy, R.; Cady, R.; Dye, S.; Gorham, P.; Learned, J.; Matsuno, S.; O' Conner, D.; Peterson, V.; Roberts, A.; Stenger, V. (Hawaii Univ., Honolulu (USA)); Barish, B. (California Inst. of Tech., Pasadena (USA)); Bradner, H. (California Univ., San Diego, La Jolla (USA)); Clem, J.; Roos, C.; Webster, M. (Vanderbilt Univ., Nashville, TN (USA)); Gaidos, J.; Wilson, C. (Purdue Univ., Lafayette, IN (USA)); Grieder, P. (Bern Univ. (Switzerland)); Kitamura, T.; Mitsui, K.; Ohashi, Y.; Okada, A. (Tokyo Univ. (Japan). Inst. for Cosmic Ray Research); Kropp, W.; Price, L.; Reines, F.; Sobel, H. (California Univ., Irvine (USA)); March, R. (Wisconsin Univ., Madison (USA)); DUMAND Collaboration

    1990-03-01

    A measurement of cosmic ray muon flux was obtained at ocean depths ranging from 2 km to 4 km at 500 m intervals off the West Coast of the Big Island of Hawaii. A brief description of the experiment and the results will be presented in this paper. (orig.).

  1. Recent developments in cosmic ray physics

    CERN Document Server

    Blasi, P

    2014-01-01

    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 $\\sim 700$ 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 crucia...

  2. Could the cosmic acceleration be transient?

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Antonio C.C.; Lima, J.A.S. [Universidade de Sao Paulo (IAG/USP), SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas

    2011-07-01

    Full text: The possibility of a transient cosmic acceleration appears in several theoretical scenarios and is theoretically interesting because it solves some difficulties inherent to eternally accelerating universes (like {Lambda}CDM). On the observational side, some authors, using a dynamical Ansatz for the dark energy equation of state, have suggested that the cosmic acceleration have already peaked and that we are currently witnessing its slowing down. Here, a possible slowing down of the cosmic expansion is investigated through a cosmographic approach. By expanding the luminous distance to fourth order and fitting the SNe Ia data from the most recent compilations (Union, Constitution and Union 2), the marginal likelihood distribution for the deceleration parameter today indicates that there is a considerable probability for q{sub 0} > 0. Also in contrast to the prediction of the {Lambda}CDM model, the cosmographic q(z) reconstruction suggests that the cosmic acceleration could already have peaked and be presently slowing down, what would imply that the recent accelerated expansion of the Universe is a transient phenomenon. It is also shown that to describe a transient acceleration the luminous distance needs to be expanded at least to fourth order. The present cosmographic results depend neither on the validity of general relativity nor on the matter-energy contents of the Universe. (author)

  3. Cosmic strings in axionic-dilatonic gravity

    Science.gov (United States)

    Santos, Caroline

    2001-05-01

    We first consider local cosmic strings in dilaton-axion gravity and show that they are singular solutions. Then we take a supermassive Higgs limit and present expressions for the fields at far distances from the core by applying a Pecci-Quinn and a duality transformation to the dilatonic Melvin's magnetic universe.

  4. Cosmic strings in axionic-dilatonic gravity

    CERN Document Server

    Santos, C

    2001-01-01

    We first consider local cosmic strings in dilaton-axion gravity and show that they are singular solutions. Then we take a supermassive Higgs limit and present expressions for the fields at far distances from the core by applying a Pecci-Quinn and a duality transformation to the dilatonic Melvin's magnetic universe.

  5. Molecular hydrogen in the cosmic recombination epoch

    CERN Document Server

    Alizadeh, Esfandiar

    2010-01-01

    The advent of precise measurements of the cosmic microwave background (CMB) anisotropies has motivated correspondingly precise calculations of the cosmic recombination history. Cosmic recombination proceeds far out of equilibrium because of a "bottleneck" at the $n=2$ level of hydrogen: atoms can only reach the ground state via slow processes: two-photon decay or Lyman-$\\alpha$ resonance escape. However, even a small primordial abundance of molecules could have a large effect on the interline opacity in the recombination epoch and lead to an additional route for hydrogen recombination. Therefore, this paper computes the abundance of the H$_2$ molecule during the cosmic recombination epoch. Hydrogen molecules in the ground electronic levels X$^1\\Sigma^+_g$ can either form from the excited H$_2$ electronic levels B$^1\\Sigma^+_u$ and C$^1\\Pi_u$ or through the charged particles H$_2^+$, HeH$^+$ and H$^-$. We follow the transitions among all of these species, resolving the rotational and vibrational sub-levels. Si...

  6. Cosmic R-string in thermal history

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Ohashi, Keisuke [Osaka City Univ. (Japan). Dept. of Mathematics and Physics; Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research

    2013-03-15

    We study stabilization of an unstable cosmic string associated with spontaneously broken U(1){sub R} symmetry, which otherwise causes a dangerous roll-over process. We demonstrate that in a gauge mediation model, messengers can receive enough corrections from the thermal plasma of the supersymmetric standard model particles to stabilize the unstable modes of the string.

  7. Anomalies of the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Hansen, Martin Anders Kirstejn

    The Cosmic Microwave Background (CMB) is the faint afterglow of the extreme conditions that existed shortly after Big Bang. The temperature of the CMB radiation across the sky is extremely uniform, yet tiny anisotropies are present, and have with recent satellite missions been mapped to very high...

  8. Spiral Arms as Cosmic Ray Source Distributions

    CERN Document Server

    Werner, M; Strong, A W; Reimer, O

    2014-01-01

    There is evidence that the distribution of suspected cosmic ray sources 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 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 f...

  9. Wave diffraction by a cosmic string

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Núñez, Isabel [Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); Institut de Ciències del Cosmos (ICCUB), Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); Bulashenko, Oleg, E-mail: oleg.bulashenko@ub.edu [Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain)

    2016-08-26

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects. - Highlights: • Gravitational waves could help us to reveal cosmic strings – topological defects of early Universe. • Wave diffraction in conical spacetime of a cosmic string is solved analytically. • The Cornu spiral is shown to appear when the string is on the line of sight. • For a string located within our galaxy, the highest amplification would occur at a frequency range of LIGO detector.

  10. Multiscale phenomenology of the cosmic web

    NARCIS (Netherlands)

    Aragón-Calvo, Miguel A.; van de Weygaert, Rien; Jones, Bernard J. T.

    2010-01-01

    We analyse the structure and connectivity of the distinct morphologies that define the cosmic web. With the help of our multiscale morphology filter (MMF), we dissect the matter distribution of a cosmological Lambda cold dark matter N-body computer simulation into cluster, filaments and walls. The

  11. New type scalar fields for cosmic acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Kehagias, A; Pakis, S [Department of Physics, National Technical University of Athens, GR-15773, Zografou, Athens (Greece)

    2007-05-15

    We present a model where a non-conventional scalar field may act like dark energy and leads to cosmic acceleration. The latter is driven by an appropriate field configuration, which result in an effective cosmological constant. The potential role of such a scalar in the cosmological constant problem is also discussed.

  12. CMB anisotropies generated by cosmic voids and great attractors. [Cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Gonzalez, E.; Sanz, J.L. (Cantabria Univ., Santander (Spain). Dept. Fisica Moderna)

    1990-12-01

    A recent result, based on the potential approximation, concerning the effect of a non-static gravitational potential on the propagation of light, is used to study the influence of compensated and uncompensated non-linear structures on the cosmic microwave background radiation. We obtain the temperature profile as well as the deflection of the microwave photons produced by the cosmic voids and great attractors whose existence has recently been claimed in the literature. (author).

  13. Isotopic Composition of Cosmic Rays:. Results from the Cosmic Ray Isotope Spectrometer on the Ace Spacecraft

    Science.gov (United States)

    Israel, M. H.

    Over the past seven years the Cosmic Ray Isotope Spectrometer (CRIS) on the ACE spacecraft has returned data with an unprecedented combination of excellent mass resolution and high statistics, describing the isotopic composition of elements from lithium through nickel in the energy interval ~ 50 to 500 MeV/nucleon. These data have demonstrated: * The time between nucleosynthesis and acceleration of the cosmic-ray nuclei is at least 105 years. The supernova in which nucleosynthesis takes place is thus not the same supernova that accelerates a heavy nucleus to cosmic-ray energy. * The mean confinement time of cosmic rays in the Galaxy is 15 Myr. * The isotopic composition of the cosmic-ray source is remarkably similar to that of solar system. The deviations that are observed, particularly at 22Ne and 58Fe, are consistent with a model in which the cosmic-ray source is OB associations in which the interstellar medium has solar-system composition enriched by roughly 20% admixture of ejecta from Wolf-Rayet stars and supernovae. * Cosmic-ray secondaries that decay only by electron capture provide direct evidence for energy loss of cosmic rays as they penetrate the solar system. This invited overview paper at ECRS 19 was largely the same as an invited paper presented a month earlier at the 8th Nuclei in the Cosmos Conference in Vancouver. The proceedings of that conference will be published shortly by Elsevier as a special edition of Nuclear Physics A. For further summary of results from CRIS, the reader is referred to URL and links on that page to CRIS and to Science News.

  14. The intergalactic propagation of ultrahigh energy cosmic ray nuclei

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-01

    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).

  15. Individual Education.

    Science.gov (United States)

    Corsini, Raymond

    1981-01-01

    Paper presented at the 66th Convention of the International Association of Pupil Personnel Workers, October 20, 1980, Baltimore, Maryland, describes individual education based on the principles of Alfred Adler. Defines six advantages of individual education, emphasizing student responsibility, mutual respect, and allowing students to progress at…

  16. Individual Education.

    Science.gov (United States)

    Corsini, Raymond

    1981-01-01

    Paper presented at the 66th Convention of the International Association of Pupil Personnel Workers, October 20, 1980, Baltimore, Maryland, describes individual education based on the principles of Alfred Adler. Defines six advantages of individual education, emphasizing student responsibility, mutual respect, and allowing students to progress at…

  17. Heliospheric Impact on Cosmic Rays Modulation

    Science.gov (United States)

    Tiwari, Bhupendra Kumar

    2016-07-01

    Heliospheric Impact on Cosmic RaysModulation B. K. Tiwari Department of Physics, A. P. S. University, Rewa (M.P.), btiwari70@yahoo.com Cosmic rays (CRs) flux at earth is modulated by the heliosphereric magnetic field and the structure of the heliosphere, controls by solar outputs and their variability. Sunspots numbers (SSN) is often treated as a primary indicator of solar activity (SA). GCRs entering the helioshphere are affected by the interplanetary magnetic field (IMF) and solar wind speed, their modulation varies with the varying solar activity. The observation based on data recoded from Omniweb data Centre for solar- interplanetary activity indices and monthly mean count rate of cosmic ray intensity (CRI) data from neutron monitors of different cut-off rigidities(Rc) (Moscow Rc=2.42Gv and Oulu Rc=0.80Gv). During minimum solar activity periodof solar cycle 23/24, the sun is remarkably quiet, weakest strength of the IMF and least dense and slowest, solar wind speed, whereas, in 2003, highest value of yearly averaged solar wind speed (~568 Km/sec) associated with several coronal holes, which generate high speed wind stream has been recorded. It is observed that GCRs fluxes reduces and is high anti-correlated with SSN (0.80) and IMF (0.86). CRI modulation produces by a strong solar flare, however, CME associated solar flare produce more disturbance in the interplanetary medium as well as in geomagnetic field. It is found that count rate of cosmic ray intensity and solar- interplanetary parameters were inverse correlated and solar indices were positive correlated. Keywords- Galactic Cosmic rays (GCRs), Sunspot number (SSN), Solar activity (SA), Coronal Mass Ejection (CME), Interplanetary magnetic field (IMF)

  18. Ultrahigh-energy particles from cosmic strings

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, P. (Chicago Univ., IL (USA). Astronomy and Astrophysics Center Fermi National Accelerator Lab., Batavia, IL (USA))

    1991-02-01

    The idea of production of ultrahigh-energy particles in the present universe due to annihilation or collapse of topological defects is discussed. Topological defects, formed in symmetry-breaking phase transitions in the early universe, can survive till today owing to their topological stability. However, under certain circumstances, topological defects may be physically destroyed. When topological defects are destroyed, the energy contained in the defects can be released in the form of massive gauge- and Higgs bosons of the underlying spontaneously broken gauge theory. Subsequent decay of these massive particles can give rise to energetic particles ranging up to an energy on the order of the mass of the original particles released from the defects. This may give us a natural'' mechanism of production of extremely energetic cosmic ray particles in the universe today, without the need for any acceleration mechanism. To illustrate this idea, I describe in detail the calculation of the expected ultrahigh-energy proton spectrum due to a specific process which involves collapse or multiple self-intersections of a class of closed cosmic string loops formed in a phase transition at a grand unification energy scale. I discuss the possibility that some of the highest-energy cosmic ray particles are of this origin. By comparing with the observational results on the ultrahigh-energy cosmic rays, we derive an upper limit to the average fraction of the total energy in all primary'' cosmic string loops that may be released in the form of particles due to collapse or multiple self-intersections of these loops. No nuclei such as {alpha}'s or Fe's are in the spectrum. 43 refs., 3 figs.

  19. Cosmic Reionization On Computers: Numerical and Physical Convergence

    CERN Document Server

    Gnedin, Nickolay Y

    2016-01-01

    In this paper I show that simulations of reionization performed under the Cosmic Reionization On Computers (CROC) project do converge in space and mass, albeit rather slowly. A fully converged solution (for a given star formation and feedback model) can be determined at a level of precision of about 20%, but such a solution is useless in practice, since achieving it in production-grade simulations would require a large set of runs at various mass and spatial resolutions, and computational resources for such an undertaking are not yet readily available. In order to make progress in the interim, I introduce a weak convergence correction factor in the star formation recipe, which allows one to approximate the fully converged solution with finite resolution simulations. The accuracy of weakly converged simulations approaches a comparable, ~20% level of precision for star formation histories of individual galactic halos and other galactic properties that are directly related to star formation rates, like stellar m...

  20. The Concepts of "Age" and "Universality" in Cosmic Ray Showers

    CERN Document Server

    Lipari, Paolo

    2008-01-01

    The concept of "age" as a parameter for the description of the state of development of high energy showers in the atmosphere has been in use in cosmic ray studies for several decades. In this work we briefly discuss how this concept, originally introduced to describe the average behavior of electromagnetic cascades, can be fruitfully applied to describe individual showers generated by primary particles of different nature, including protons, nuclei and neutrinos. Showers with the same age share three different important properties: (i) their electron size has the same fractional rate of change with increasing depth, (ii) the bulk of the electrons and photons in the shower (excluding high energy particles) have energy spectra with shapes and relative normalization uniquely determined by the age parameter, (iii) the electrons and photons in the shower have also the same angular and lateral distributions sufficiently far from the shower axis. In this work we discuss how the properties associated with the shower ...