Effects of hysteresis in solar cycle variations between flare index and cosmic rays

We study the hysteresis effect between the solar flare index and cosmic ray intensity for the past 37 years from January 1, 1965 to December 31, 2001 on a daily basis. We show that smoothed time series of flare index and the daily Calgary Galactic Cosmic Ray intensity values exhibit significant solar cycle dependent differences in their relative variations during the studied period. The shapes of these differences vary from cycle to cycle. So we investigate the momentary time lags between the two time series for the odd and even cycles.     

Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach

We present the first tests of a new method, the correlated component analysis (CCA) based on second-order statistics, to estimate the mixing matrix, a key ingredient to separate astrophysical foregrounds superimposed to the Cosmic Microwave Background (CMB). In the present application, the mixing matrix is parametrized in terms of the spectral indices of Galactic synchrotron and thermal dust emissions, while the free–free spectral index is prescribed by basic physics, and is thus assumed to be known. We consider simulated observations of the microwave sky with angular resolution and white stationary noise at the nominal levels for the Planck satellite, and realistic foreground emissions, with a position-dependent synchrotron spectral index. We work with two sets of Planck frequency channels: the low-frequency set, from 30 to 143 GHz, complemented with the Haslam 408 MHz map, and the high-frequency set, from 217 to 545 GHz. The concentration of intense free–free emission on the Galactic plane introduces a steep dependence of the spectral index of the global Galactic emission with Galactic latitude, close to the Galactic equator. This feature makes difficult for the CCA to recover the synchrotron spectral index in this region, given the limited angular resolution of Planck , especially at low frequencies. A cut of a narrow strip around the Galactic equator  (| b | < 3°)  , however, allows us to overcome this problem. We show that, once this strip is removed, the CCA allows an effective foreground subtraction, with residual uncertainties inducing a minor contribution to errors on the recovered CMB power spectrum.     

The measurement of the decorrelation function in underground muon pairs as a probe of primary cosmic ray interactions

We discuss the measurement of the average angle within pairs of muons detected in underground experiments versus their relative distance, as a tool for studying primary Cosmic Ray interactions. We propose to call Φ(d) “decorrelation” function. Under simplifying approximation, the decorrelation function can be computed analytically to show its dependence on details of cosmic ray interactions as well as on the propagation in the rock. We argue that this new measurement is useful in a real experiment, complementing traditional ones like the decoherence function.     

Multi‐Messenger Cosmic Particles

A54 Cosmic Ray Acceleration in Galactic Wind Shocks A71 Detection of Ultra‐High Energy Cosmic Rays and Neutrinos with LOFAR A80 Status of the gravitational‐wave detector GEO600 A87 Recent Results and Future of the MAGIC gamma‐ray telescope A92 Cosmic ray detection with the radio technique A93 Cosmic Ray Physics with IceCube A94 The resonance‐like gamma‐ray absorption processes for use in astrophysics A97 Geometry reconstruction of air shower fluorescence detectors revisited A102 Supermassive Binary Black Holes & Radio Jets A108 Muonic Component of Air Showers Measured by KASCADE‐Grande A110 Towards new frontiers: observation of photons with energies above 10¹⁸ eV A112 The IceCube Neutrino Telescope A114 The ground‐based gamma‐ray observatory CTA A116 IceCube: Recent Results and Prospects A117 Particle Physics with AMANDA and IceCube A118 Altitude dependence of fluorescence light emission by extensive air showers A120 Neutrino‐induced cascades in AMANDA & IceCube A122 Enhancement Telescopes for the Pierre Auger Southern Observatory in Argentina A123 Proton spectra from relativistic shock environments in AGN and GRBs A124 The Baikal Neutrino Telescope – Physics Results A127 Searches for point‐like sources of cosmic neutrinos with IceCube A128 The MAGIC/IceCube Target of Opportunity Programtest run A131 Supernova detection with IceCube: from low to high energy neutrinos A132 Measurement of the UHECR energy spectrum from hybrid data of the Pierre Auger Observatory A133 Extension of IceCube at Lower Energy: the Use of AMANDA as Nested Array and the Future Prospectives A135 Searching for neutrinos with the Pierre Auger Observatory A138 Search for Transient Emission of Neutrinos in IceCube A140 Acoustic Neutrino Detection in Antarctic Ice A159 AMANDA limits on the diffuse muon‐neutrino flux: physics implications A164 Investigation of the Radio Emission of Cosmic Ray Air Showers with LOPES A168 The Northern Site of the Pierre Auger Observatory A170 Shower reconstruction and size spectra with KASCADE‐Grande data A171 Neutrinos from Gamma Ray Bursts: predictions and limits from AMANDA‐II data A172 Simulation study of shower profiles from ultra‐high energy cosmic rays A174 Upper limit to the photon fraction in cosmic rays above 10¹⁹ eV from the Pierre Auger Observatory A176 Astrophysics at MeV energies A180 Study of the Cosmic Ray Composition above 0.4 EeV using the Longitudinal Profiles of Showers observed at the Pierre Auger Observatory A185 Backgrounds for UHE horizontal neutrino showers A186 The Front‐End Cards of the Pierre Auger Surface Detectors: Test Results and Performance in the Field A187 Monte Carlo Studies for MAGIC‐II A194 Measuring the proton‐air cross section from logitudinal air shower profiles A195 The UHECR energy spectrummeasured at the Pierre Auger Observatory A203 Highlights of Observations of Galactic Sources with the MAGIC telescope A207 Adesign study for a 12.5 m ∅︁ Imaging Air Cherenkov Telescope for ground‐based γ ‐ray astronomy A210 The Future of Long‐Wavelengths Radio‐Astronomy in Germany: LOFAR and GLOW A211 Online Monitoring of the Pierre Auger Observatory A216 OPTIMA‐Burst – Catching GRB Afterglows (and other Transients) with High Time Resolution A227 JEM‐EUSO mission A232 Rapid Variations in AGN: Clues on Particle Accelerators A235 Systematic search forVHEgamma‐ray emission from X‐ray bright high‐frequency peaked BL Lac objects A237 Prospects for GeV Astronomy in the Era of GLAST A241 Improvements of the energy reconstruction for the MAGIC telescope by means of analysis and Monte Carlo techniques A265 Discovery of VHE γ ‐rays from BL Lacertae with the MAGIC telescope A266 Results of two observation cycles of LS I+61°303 with the MAGIC telescope A267 Wide Range Multifrequency Observations of Northern TeV Blazars A269 Diffusive and convective cosmic ray transport in elliptical galaxies     

Ultrahigh energy nuclei in the turbulent Galactic magnetic field

In this work we study how the turbulent component of the Galactic magnetic field (GMF) affects the propagation of ultrahigh energy heavy nuclei. We investigate first how the images of individual sources and of the supergalactic plane depend on the properties of the turbulent GMF. Then we present a quantitative study of the impact of the turbulent field on (de-)magnification of source fluxes, due to magnetic lensing effects. We also show that it is impossible to explain the Pierre Auger data assuming that all ultrahigh energy nuclei are coming from Cen A, even in the most favorable case of a strong, extended turbulent field in the Galactic halo.     

Simulations of Galactic Cosmic Ray impacts onto the Herschel/PACS photoconductor arrays with Geant4 code

We present results of simulations performed with the Geant4 software code of the effects of Galactic Cosmic Ray impacts on the photoconductor arrays of the PACS instrument. This instrument is part of the ESA-Herschel payload, which will be launched in 2008 and will operate at the Lagrangian L2 point of the Sun-Earth system. Both the Satellite plus the cryostat (the shield) and the detector act as source of secondary events, affecting the detector performance. Secondary event rates originated within the detector and from the shield are of comparable intensity. The impacts deposit energy on each photoconductor pixel but do not affect the behaviour of nearby pixels. These latter are hit with a probability always lower than 7%. The energy deposited produces a spike which can be hundreds times larger than the noise. We then compare our simulations with proton irradiation tests carried out for one of the detector modules and follow the detector behaviour under ‘real’ conditions.     

Jets from Young Stars and Compact Objects Environments

Several classes of cosmic objects, such as Young Stellar Objects, Active Galactic Nuclei, Micro-Quasars, Pulsars and probably Gamma Ray Bursts, display powerful winds and jets; for some of them the flow is even ultrarelativistic. For all these classes of objects, the magnetic field is supposed to play a major role in launching and collimating the flow, together with the angular momentum transfer. It probably plays an important role for the turbulent transport in accretion disks also. Regarding the high energy radiation of relativistic jets and the cosmic ray generation, the magnetic field is of course the acceleration agent and could produce the Ultra High Energy Cosmic Rays in some extragalactic objects. The main growth points of these topics are presented, mostly in the case of black hole environments; the case of Young Stellar Objects is more complicated because of the interaction of the stellar magnetosphere with the accretion disk, and the models for this interaction are not yet founded on a reliable theory.     

The parabolic wave equation in local helioseismology

In recent years methods of time-distance helioseismology have been used to produce maps of local flows in the surface layers of the Sun. Usually, these studies rely on ray theory to describe the propagation of sound waves. Ray theory, however, is a poor approximation of the acoustic wavefield near the surface of the Sun. In particular, it is inappropriate for the study of scattering and diffraction by inhomogeneities. But an exact solution of the acoustic wave equation in the Sun is not trivial. In this paper I present an approximation to the full wave equation, which transforms it into a parabolic equation. The parabolic equation is commonly used in ocean acoustics and geoseismology because it is much simpler to solve numerically. Here I discuss the parabolic approximation, its limitations and potential applications in helioseismology. Finally, I present some numerical results to demonstrate the capabilities of this method.     

The Parkes Multibeam Pulsar Survey – VI. Discovery and timing of 142 pulsars and a Galactic population analysis

We present the discovery and follow-up observations of 142 pulsars found in the Parkes 20-cm multibeam pulsar survey of the Galactic plane. These new discoveries bring the total number of pulsars found by the survey to 742. In addition to tabulating spin and astrometric parameters, along with pulse width and flux density information, we present orbital characteristics for 13 binary pulsars which form part of the new sample. Combining these results from another recent Parkes multibeam survey at high Galactic latitudes, we have a sample of 1008 normal pulsars which we use to carry out a determination of their Galactic distribution and birth rate. We infer a total Galactic population of  30 000 ± 1100  potentially detectable pulsars (i.e. those beaming towards us) having 1.4-GHz luminosities above 0.1 mJy kpc². Adopting the Tauris & Manchester beaming model, this translates to a total of  155 000 ± 6000  active radio pulsars in the Galaxy above this luminosity limit. Using a pulsar current analysis, we derive the birth rate of this population to be  1.4 ± 0.2  pulsars per century. An important conclusion from our work is that the inferred radial density function of pulsars depends strongly on the assumed distribution of free electrons in the Galaxy. As a result, any analyses using the most recent electron model of Cordes & Lazio predict a dearth of pulsars in the inner Galaxy. We show that this model can also bias the inferred pulsar scaleheight with respect to the Galactic plane. Combining our results with other Parkes multibeam surveys we find that the population is best described by an exponential distribution with a scaleheight of 330 pc. Surveys underway at Parkes and Arecibo are expected to improve the knowledge of the radial distribution outside the solar circle, and to discover several hundred new pulsars in the inner Galaxy.     

The goddard program of gamma-ray transient astronomy

The Goddard program of gamma-ray burst studies is briefly reviewed. The past results, present status and future expectations are outlined regarding our endeavors using experiments on balloons, IMP-6 and IMP-7, OGO-3, ISEE-1 and ISEE-3, Helios-2, Solar Maximum Mission, the Einstein Observatory, Solar Polar and the Gamma Ray Observatory, and with the interplanetary gamma-ray burst networks, to which some of these spacecraft sensors contribute. Additional emphasis is given to the recent discovery of a new type of gamma-ray transient, detected on 5 March, 1979.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts held at Toulouse, France, 26–29 November, 1979.     

On the Study of the Spatial Variability of the Composition of the Lunar Material in Experiments on Gamma Spectroscopy Onboard a Mobile Spacecraft Using the Tagged-Cosmic-Rays Method

Solar System Research - The article proposes a “tagged cosmic particle” method that uses the natural flux of high-energy particles of Galactic Cosmic Rays to study the composition of...     

Search of ultra high energy cosmic rays’ sources. FRI-radiogalaxy Centaurus A

The propagation of ultra high energy cosmic rays in Galactic and extragalactic magnetic fields is investigated in the present paper. The motion of charged particles of different energies and chemical composition is simulated using different Galactic magnetic field models. Positions for the real sources of events registered at the Auger observatory are calculated taking into account the influence of both Galactic and extragalactic turbulent fields. The possibility of their correlation with the Centaurus A radio galaxy is analyzed.     

A new family of multistep numerical integration methods based on Hermite interpolation

In this paper, a new family of explicit and implicit multistep methods is presented both for the error-controlled and uncontrolled modes. The main concept is to replace the Newton interpolation with the Hermite interpolation, where the Hermite polynomial is fitted to the function values and its derivatives. This idea is very useful in the numerical solution of problems (e.g., orbit propagation problem) where higher-order derivatives can easily be computed. In addition to the theoretical concept, the stability regions of the proposed methods are determined. The new methods are more stable than the well-known multistep numerical integrators (i.e., Adams–Bashforth and Adams–Bashforth–Moulton) in the explicit, implicit, and predictor–corrector forms. Using the second-order derivatives gives smaller error constants in the proposed method. The new integrators are numerically tested for a few examples, and the solutions are compared with those of the well-known multistep methods. Moreover, the CPU time and absolute integration error are compared in the satellite orbit propagation problem using various integration methods. The CHAMP mission, i.e., a German small-satellite mission for geoscientific and atmospheric research and applications, is considered as a case study for comparing the achievable accuracy of the proposed method with the existing method for solving the two-body problem.     

Analytic calculations of the spectra of ultra high energy cosmic ray nuclei. II. The general case of background radiation

We discuss the problem of ultra high energy nuclei propagation in extragalactic background radiations. The present paper is the continuation of the accompanying paper I where we have presented three new analytic methods to calculate the fluxes and spectra of ultra high energy cosmic ray nuclei, both primary and secondary, and secondary protons. The computation scheme in this paper is based on the analytic solution of coupled kinetic equations, which takes into account the continuous energy losses due to the expansion of the universe and pair-production, together with photo-disintegration of nuclei. This method includes in the most natural way the production of secondary nuclei in the process of photo-disintegration of the primary nuclei during their propagation through extragalactic background radiations. In paper I, in order to present the suggested analytical schemes of calculations, we have considered only the case of the cosmic microwave background radiation, in the present paper we generalize this computation to all relevant background radiations, including infra-red and visible/ultra-violet radiations, collectively referred to as extragalactic background light. The analytic solutions allow transparent physical interpretation of the obtained spectra. Extragalactic background light plays an important role at intermediate energies of ultra high energy cosmic ray nuclei. The most noticeable effect of the extragalactic background light is the low-energy tail in the spectrum of secondary nuclei.     

Non-Sobolev modelling of radiation-pressure-driven flows in active galactic nuclei

We present a new general scheme for calculating the structure and dynamics of radiation-pressure-driven photoionized flows. The new method goes one step beyond the Sobolev approximation. It involves a numerical solution of the radiative transfer in absorption lines, including the effects of differential expansion and line interactions such as line locking and blanketing. We also present a new scheme for calculating the radiation pressure due to trapped line photons in finite, differentially expanding flows. We compare our results for the radiation pressure force with those obtained using the Sobolev approximation and show the limitations of the latter. In particular, we demonstrate that the Sobolev method gives a poor approximation near discontinuity surfaces and its neglect of line blanketing can lead to erroneous results in high-velocity flows. We combine the newly calculated radiation pressure force with self-consistent photoionization and thermal calculations to study the dynamics and spectral features of broad absorption-line flows and highly ionized gas flows in active galactic nuclei (AGN). A comparison with Sobolev-type calculations shows that the latter overestimates the terminal velocity of the flow and, conversely, underestimates its opacity. We also show that line locking on broad emission lines can have a significant effect on the dynamics and spectral features of AGN flows.     

Cosmic rays from the galactic center

We examine the possibility that recent data on cosmic ray anisotropies presented by the AGASA group may lead to the conclusion that our Galactic Center is a major source of the highest energy cosmic rays in our galaxy. We discuss how such a source would contribute to the magnitude and directional properties of the observed flux when measured against a background of extragalactic cosmic rays. We do this using the results of previous propagation calculations and our own more recent calculations which are specifically for a Galactic Center source.We find that the AGASA data can indeed be plausibly interpreted in this way and also that an argument can be made that the Galactic Center has the appropriate physical properties for acceleration to energies of the order of 10¹⁸ eV. We show that data from the SUGAR array are compatible with the AGASA result.     

Strong-field tests of gravity using pulsars and black holes

The sensitivity of the SKA enables a number of tests of theories of gravity. A Galactic Census of pulsars will discover most of the active pulsars in the Galaxy beamed toward us. In this census will almost certainly be pulsar–black hole binaries as well as pulsars orbiting the super-massive black hole in the Galactic centre. These systems are unique in their capability to probe the ultra-strong field limit of relativistic gravity. These measurements can be used to test the Cosmic Censorship Conjecture and the No-Hair theorem.The large number of millisecond pulsars discovered with the SKA will also provide a dense array of precision clocks on the sky. These clocks will act as the multiple arms of a huge gravitational wave detector, which can be used to detect and measure the stochastic cosmological gravitational wave background that is expected from a number of sources.     

Dynamics of interacting generalized cosmic Chaplygin gas in brane-world scenario

In this work we explore the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by brane cosmology. Here DGP and the RSII brane models have been considered separately. Dark energy in the form of Generalized Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is considered in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy models. Graphs and phase diagrams are drawn to study the variations of these parameters. It is also seen that the background dynamics of Generalized Cosmic Chaplygin gas is consistent with the late cosmic acceleration, but not without satisfying certain conditions. It has been shown that the universe in both the models follows the power law form of expansion around the critical point, which is consistent with the known results. Future singularities were studied and our models were declared totally free from any types of such singularities. Finally, some cosmographic parameters were also briefly studied. Our investigation led to the fact that although Generalized cosmic Chaplygin gas with a far lesser negative pressure compared to other dark energy models, can overcome the relatively weaker gravity of RS II brane, with the help of the negative brane tension, yet for the DGP brane model with much higher gravitation, the incompetency of Generalized cosmic Chaplygin gas is exposed, and it cannot produce the accelerating scenario until it reaches the phantom era.     

Formation of the Galactic Stellar Halo: Origin of the Metallicity-Eccentricity Relation

Motivated by the recently improved knowledge on the kinematic and chemical properties of the Galactic metal-poor stars, we present the numerical simulation for the formation of the Galactic stellar halo to interpret the observational results. As a model for the Galaxy contraction, we adopt the currently standard theory of galaxy formation based on the hierarchical assembly of the cold dark matter fluctuations. We find, for the simulated stars with &sqbl0;Fe&solm0;H&sqbr0;相似文献   

Pulsar sensitivity studies of the GLAST large area telescope

In this contribution we present our preliminary investigation on pulsar sensitivity of the Large Area Telescope, the main instrument aboard the GLAST mission. In particular we concentrated our attention to pulsars located at low galactic latitudes. We created a set of simulated pulsars having different fluxes in an array of galactic coordinates separated by a distance greater than the LAT Point Spread Function in order to avoid confusion between adjacent sources. Galactic gamma-ray sky background as used during the second LAT Data Challenge (DC2) is also included. We then run an automatic routine for testing periodicity for all the pulsars considering an opportune timing solution. In this way we can obtain a map of the sensitivity of the periodic searches for different fluxes and for various Galactic latitudes. Some assumptions have been made by simulating the pulsar sources, but this study is a first step toward an estimate for pulsed emission sensitivity of the GLAST LAT. The pulsed flux sensitivity profile we generate could also be input to a population synthesis code of Galactic pulsars in order to obtain more accurate predictions of the number of expected pulsar detections by GLAST. On behalf of the GLAST LAT Collaboration.