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Sample records for cosmic x rays

  1. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  2. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  3. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  4. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  5. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

  6. Development of cosmic x-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Hayato, Asami; Tamagawa, Toru; Tsunoda, Naoko; Hashimoto, Shigehira; Miyamoto, Masao; Kohama, Mitsuhiro; Tokanai, Fuyuki; Hamagaki, Hideki; Inuzuka, Masahide; Miyasaka, Hiromasa; Sakurai, Ikuya; Makishima, Kazuo

    2006-06-01

    We present a performance study of a cosmic X-ray polarimeter which is based on the photoelectric effect in gas, and sensitive to a few to 30 keV range. In our polarimeter, the key device would be the 50 μm pitch Gas Electron Multiplier (GEM). We have evaluated the modulation factor using highly polarized X-ray, provided by a synchrotron accelerator. In the analysis, we selected events by the eccentricity of the charge cloud of the photoelectron track. As a result, we obtained the relationship between the selection criteria for the eccentricity and the modulation factors; for example, when we selected the events which have their eccentricity of > 0.95, the polarimeter exhibited with the modulation factor of 0.32. In addition, we estimated the Minimum Detectable Polarization degree (MDP) of Crab Nebula with our polarimeter and found 10 ksec observation is enough to detect the polarization, if we adopt suitable X-ray mirrors.

  7. X-ray Observations of Cosmic Ray Acceleration

    NASA Technical Reports Server (NTRS)

    Petre, Robert

    2012-01-01

    Since the discovery of cosmic rays, detection of their sources has remained elusive. A major breakthrough has come through the identification of synchrotron X-rays from the shocks of supernova remnants through imaging and spectroscopic observations by the most recent generation of X-ray observatories. This radiation is most likely produced by electrons accelerated to relativistic energy, and thus has offered the first, albeit indirect, observational evidence that diffusive shock acceleration in supernova remnants produces cosmic rays to TeV energies, possibly as high as the "knee" in the cosmic ray spectrum. X-ray observations have provided information about the maximum energy to which these shOCks accelerate electrons, as well as indirect evidence of proton acceleration. Shock morphologies measured in X-rays have indicated that a substantial fraction of the shock energy can be diverted into particle acceleration. This presentation will summarize what we have learned about cosmic ray acceleration from X-ray observations of supernova remnants over the past two decades.

  8. X-ray Production By Cosmic Muons

    NASA Astrophysics Data System (ADS)

    Mrdja, D.; Bikit, I.; Aničin, I.; Vesković, M.; Forkapić, S.

    2007-04-01

    Muons have a small cross section for interactions and high energy, so they are very penetrating and give the significant contribution to the gamma spectra of Ge detectors, even in deep underground laboratories. One of the muon interaction effects with material is X-rays production. Having in mind that gold is often used as a detectors component, in this paper the production of X-rays in gold sample is analyzed by using an coincidence system based on plastic scintillation detector and Ge detector. The Au disc-shaped sample with mass of 40.6 g, radius 3.34 cm and 0.06 cm thickness was inside 12 cm thick lead shield of extended range HPGe detector. The plastic detector of 0.5 × 0.5 × 0.05 m dimensions was placed above the lead shield at the distance of 32 cm from detector endcap. The producing rate of Kα rays per Au mass unit from coincidence gamma spectrum is determined as R ~7.1 × 10-4 g-1s-1. Taking in account the measured muon flux of Φ=54 s-1m-2, the muon cross section σKα~ 43 Barn, for Au Kα X-rays production is calculated. Also, the cross sections of X-ray production by cosmic muons in lead and tungsten are measured. Unexpectedly, the results obtained did not reveal Z dependence in the Z= 74-82 region.

  9. A New Measurement of the Cosmic X-ray Background

    SciTech Connect

    Moretti, A.

    2009-05-11

    I present a new analytical description of the cosmic X-ray background (CXRB) spectrum in the 1.5-200 keV energy band, obtained by combining the new measurement performed by the Swift X-ray telescope (XRT) with the recently published Swift burst alert telescope (BAT) measurement. A study of the cosmic variance in the XRT band (1.5-7 keV) is also presented. I find that the expected cosmic variance (expected from LogN-LogS) scales as {omega}{sup -0.3}(where {omega} is the surveyed area) in very good agreement with XRT data.

  10. Spectra of cosmic x-ray sources

    SciTech Connect

    Holt, S.S.; Mccray, R.

    1982-02-01

    X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term spectroscopy as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.

  11. Spectra of cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Mccray, R.

    1982-01-01

    X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term "spectroscopy" as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.

  12. Transition radiation as a source of cosmic X-rays.

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Bleach, R. D.

    1972-01-01

    It is shown that transition radiation generated during the passage of relativistic charged particles through interstellar grains can be an important source of cosmic X-rays. In order to account for recent X-ray observations below 300 eV by transition radiation, an energy density in interstellar space of about 10 eV per cu cm in 10 MeV electrons is required. This seems to rule out transition radiation as an important source of diffuse cosmic X-rays in any energy region.

  13. Ionization and heating by X-rays and cosmic rays

    NASA Astrophysics Data System (ADS)

    Güdel, Manuel

    2015-09-01

    High-energy radiation from the central T Tauri and protostars plays an important role in shaping protoplanetary disks and influences their evolution. Such radiation, in particular X-rays and extreme-ultraviolet (EUV) radiation, is predominantly generated in unstable stellar magnetic fields (e.g., the stellar corona), but also in accretion hot spots. Even jets may produce X-ray emission. Cosmic rays, i.e., high-energy particles either from the interstellar space or from the star itself, are of crucial importance. Both highenergy photons and particles ionize disk gas and lead to heating. Ionization and heating subsequently drive chemical networks, and the products of these processes are accessible through observations of molecular line emission. Furthermore, ionization supports the magnetorotational instability and therefore drives disk accretion, while heating of the disk surface layers induces photoevaporative flows. Both processes are crucial for the dispersal of protoplanetary disks and therefore critical for the time scales of planet formation. This chapter introduces the basic physics of ionization and heating starting from a quantum mechanical viewpoint, then discusses relevant processes in astrophysical gases and their applications to protoplanetary disks, and finally summarizes some properties of the most important high-energy sources for protoplanetary disks. 14th Lecture from Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

  14. Cosmic X-ray spectroscopy with multilayer optics

    NASA Technical Reports Server (NTRS)

    Walker, Arthur B. C., Jr.; Martinez, Dennis S.; Paris, Elizabeth S.; Hoover, Richard B.; Barbee, Troy W., Jr.

    1992-01-01

    Multilayer optics operated at normal incidence offer a powerful new technology for the study of the solar spectrum in the XUV. The spectra of most cosmic X-ray sources are strongly extinguished at wavelengths above 40 A due to absorption and scattering by interstellar grains. We describe a number of configurations which allow multilayer optics to be used at nonnormal angles of incidence in conjunction with grazing incidence optics to analyze the spectra of cosmic X-ray sources in the wavelength interval between 1.5 and 40 A. These optical configurations utilize both multilayer mirrors and gratings, and permit the efficient observation of extended sources using stigmatic spectrographs. The response of the instruments described to typical cosmic X-ray sources is also discussed.

  15. High resolution X- and gamma-ray spectroscopy of cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Lin, R. P.

    1983-01-01

    A high resolution X-ray spectrometer and large area phoswich detector were designed and co-aligned in a common elevation mounting in order to measure solar and cosmic X-ray and gamma ray emission in the 13 to 600 KeV energy range from a balloon. The instrument is described and results obtained for the Crab Nebula, the supernova remnant Cas A, and the Sun are discussed and analyzed.

  16. The radiation monitor cosmic X-ray experiment OSO-1

    NASA Technical Reports Server (NTRS)

    Randall, R. F.

    1973-01-01

    A comprehensive technical description is presented of the Radiation Monitor which is part of the GSFC cosmic X-ray experiment to be flown on the OSO-1 satellite. The theory of operation, fabrication and assembly, and cone angle determination are reported.

  17. The AGN Population and the Cosmic X-ray Background

    NASA Astrophysics Data System (ADS)

    Treister, Ezequiel; Urry, C. Meg; Schawinski, Kevin

    2015-08-01

    In order to fully understand galaxy formation we need to know when in the cosmic history are supermassive black holes (SMBHs) growing more intensively, in what type of galaxies this growth is happening and what fraction of these sources are invisible at most wavelengths due to obscuration. Active Galactic Nuclei (AGN) population synthesis models that can explain the spectral shape and intensity of the cosmic X-ray background (CXRB) indicate that most of the SMBH growth occurs in moderate-luminosity (Lx~1044 erg/s) sources (Seyfert-type AGN), at z~0.5-1 and in heavily obscured but Compton-thin, NH~1023 cm-2, systems.However, this is not the complete history, as a large fraction of black hole growth does not emit significantly in X-rays either due to obscuration, intrinsic low luminosities or large distances. Using a combination of X-ray stacking and multi wavelength selection techniques we constrain the amount of black hole accretion as a function of cosmic history, from z~0 to z~6. The integrated intensity at high energies indicates that a significant fraction of the total black hole growth, 22%, occurs in heavily-obscured systems that are not individually detected in even the deepest X-ray observations.We finally investigate the AGN triggering mechanism as a function of bolometric luminosity, finding evidence for a strong connection between significant black hole growth events and major galaxy mergers from z~0 to z~3, while less spectacular but longer accretion episodes are most likely due to other (stochastic) processes. AGN activity triggered by major galaxies is responsible for ~60% of the total black hole growth.

  18. A search for X-ray polarization in cosmic X-ray sources. [binary X-ray sources and supernovae remnants

    NASA Technical Reports Server (NTRS)

    Hughes, J. P.; Long, K. S.; Novick, R.

    1983-01-01

    Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission.

  19. NASA and Japanese X-ray observatories Clarify Origin of Cosmic Rays

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Recent observations from NASA and Japanese X-ray observatories have helped clarify one of the long-standing mysteries in astronomy -- the origin of cosmic rays. This image from Japan's Suzaku X-ray observatory shows RXJ1713.7-3946. This supernova remnant is the gaseous remnant of a massive star that exploded. The remnant is about 1,600 years old. The contour lines show where gamma-ray intensity is highest, as measured by the High Energy Stereoscopic System (HESS) in Namibia.

  20. Conical focusing crystal spectrometers for cosmic X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Woodgate, B. E.; Lowinger, T.; Schneider, M.

    1973-01-01

    A crystal spectrometer for rocket and satellite experiments is described. Parallel X rays from a stellar object are reflected at constant angle by Bragg crystals arranged around the sector of a cone so that a single wavelength is brought to a focus onto the axis of the cone. The aberrations produced when this array is tilted to change the wavelength are considered. It is shown that these are minimized by moving cone and detector in a nearly theta to two-theta motion and by using a small-angle sector. In a specific design for a satellite instrument using LiF crystal to observe a spectral region including the iron lines at 1.9 A, a spectral resolution of 3 mA over a spectral range of 1.6-2.1 A can be obtained, with the cosmic-ray background rate, and hence the time to detect a weak line decreased by a factor 80 compared to a flat crystal spectrometer. Examples of performance for a low energy rocket experiment are also given.

  1. X-Ray Absorbed, Broad-Lined, Red AGN and the Cosmic X-Ray Background

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Wilkes, Belinda

    2005-01-01

    We have obtained XMM spectra for five red, 2MASS AGN, selected from a sample observed by Chandra to be X-ray bright and to cover a range of hardness ratios. Our results confirm the presence of substantial absorbing material in three sources which have optical classifications ranging from Type 1 to Type 2, with an intrinsically flat (hard) power law continuum indicated in the other two. The presence of both X-ray absorption and broad optical emission lines with the usual strength suggests either a small (nuclear) absorber or a favored viewing angle so as to cover the X-ray source but not the broad emission line region (BELR). A soft excess is detected in all three Type 1 sources. We speculate that this soft X-ray emission may arise in an extended region of ionized gas, perhaps linked with the polarized (scattered) light which is a feature of these sources. The spectral complexity revealed by XMM emphasizes the limitations of the low S/N Chandra data. Overall, the new XMM results strengthen our conclusions (Wilkes et al. 2002) that the observed X-ray continua of red AGN are unusually hard at energies greater than 2 keV. Whether due to substantial line-of-sight absorption or to an intrinsically hard or reflection-dominated spectrum, these 'red' AGN have an observed spectral form consistent with contributing significantly to the missing had absorbed population of the Cosmic X-ray Background (CXRB). When absorption and or reflection is taken into account, all these AGN have power law slopes typical of broad-line (Type 1) AGN (Gamma approximately 1.9). This appears to resolve the spectral paradox which for so long has existed between the CXRB and the AGN thought to be the dominant contributors. It also suggests two scenarios whereby Type 1 AGN/QSOs may be responsible for a significant fraction of the CXRB at energies above 2 keV: 1) X-ray absorbed AGN/QSOs with visible broad emission lines; 2) AGN/QSOs with complex spectra whose hardness greater than 2 keV is not

  2. A cosmic and solar X-ray and gamma-ray instrument for a scout launch

    NASA Technical Reports Server (NTRS)

    Forrest, D. J.; Vestrand, W. T.; Chupp, E. L.

    1988-01-01

    An overview is presented for a set of simple and robust X-ray and gamma ray instruments which have both cosmic and solar objectives. The primary solar scientific objective is the study of the beaming of energetic electrons and ions in solar flares. The instrument will measure spectra and polarization of flare emissions up to 10 MeV. At X-ray energies both the directly emitted flux and the reflected albedo flux will be measured with a complement of six X-ray sensors. Each of these detectors will have a different high Z filter selected to optimize both the energy resolution and high rate capabilities in the energy band 10 to 300 keV. At energies greater than 100 keV seven 7.6 x 7.6 cm NaI and a set of 30 concentric plastic scattering detectors will record the spectra and polarization of electron bremsstrahlung and nuclear gamma rays. All of the components of the instrument are in existence and have passed flight tests for earlier space missions. The instrument will use a spinning solar oriented Scout spacecraft. The NaI detectors will act as a self-modulating gamma ray detector for cosmic sources in a broad angular band which lies at 90 degrees to the Sun-Earth vector and hence will scan the entire sky in 6 months.

  3. A cosmic X-ray astronomy bibliography: The Astrophysical Journal, 1962 to 1972

    NASA Technical Reports Server (NTRS)

    Wilson, R. M.

    1972-01-01

    The results are presented of a survey of the Astrophysical Journal for the period January 1962 through March 1972 (volumes 135-172). Some 395 references are contained within this document related to cosmic X-ray astronomy.

  4. The UCSD high energy X-ray timing experiment cosmic ray particle anticoincidence detector

    NASA Technical Reports Server (NTRS)

    Hink, P. L.; Rothschild, R. E.; Pelling, M. R.; Macdonald, D. R.; Gruber, D. E.

    1991-01-01

    The HEXTE, part of the X-Ray Timing Explorer (XTE), is designed to make high sensitivity temporal and spectral measurements of X-rays with energies between 15 and 250 keV using NaI/CsI phoswich scintillation counters. To achieve the required sensitivity it is necessary to provide anticoincidence of charged cosmic ray particles incident upon the instrument, some of which interact to produce background X-rays. The proposed cosmic ray particle anticoincidence shield detector for HEXTE uses a novel design based on plastic scintillators and wavelength-shifter bars. It consists of five segments, each with a 7 mm thick plastic scintillator, roughly 50 cm x 50 cm in size, coupled to two wavelength-shifter bars viewed by 1/2 inch photomultiplier tubes. These segments are configured into a five-sided, box-like structure around the main detector system. Results of laboratory testing of a model segment, and calculations of the expected performance of the flight segments and particle anticoincidence detector system are presented to demonstrate that the above anticoincidence detector system satisfies its scientific requirements.

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  6. Cosmic X-ray and gamma-ray background from dark matter annihilation

    NASA Astrophysics Data System (ADS)

    Zavala, Jesús; Vogelsberger, Mark; Slatyer, Tracy R.; Loeb, Abraham; Springel, Volker

    2011-06-01

    The extragalactic background light (EBL) observed at multiple wavelengths is a promising tool to probe the nature of dark matter. This radiation might contain a significant contribution from gamma-rays produced promptly by dark matter particle annihilation in the many halos and subhalos within our past-light cone. Additionally, the electrons and positrons produced in the annihilation give energy to the cosmic microwave photons to populate the EBL with X-rays and gamma-rays. To study these signals, we create full-sky maps of the expected radiation from both of these contributions using the high-resolution Millennium-II simulation of cosmic structure formation. Our method also accounts for a possible enhancement of the annihilation rate by a Sommerfeld mechanism due to a Yukawa interaction between the dark matter particles prior to annihilation. We use upper limits on the contributions of unknown sources to the EBL to constrain the intrinsic properties of dark matter using a model-independent approach that can be employed as a template to test different particle physics models. These upper limits are based on observational measurements spanning 8 orders of magnitude in energy (from soft X-rays measured by the CHANDRA satellite to gamma-rays measured by the Fermi satellite), and on expectations for the contributions from nonblazar active galactic nuclei, blazars and star-forming galaxies. To exemplify this approach, we analyze a set of benchmark Sommerfeld-enhanced models that give the correct abundance of dark matter, satisfy constraints from the cosmic microwave background, and fit the cosmic ray spectra measured by PAMELA and Fermi without any contribution from local substructure. We find that these models are in conflict with the EBL constraints unless the contribution of unresolved substructure is small and the dark matter annihilation signal dominates the EBL. We conclude that provided the collisionless cold dark matter paradigm is accurate, even for

  7. X-Ray Probes of Cosmic Star-Formation History

    NASA Technical Reports Server (NTRS)

    Ghosh, Pranab; White, Nicholas E.

    2001-01-01

    In a previous paper we point out that the X-ray luminosity L(sub x) of a galaxy is driven by the evolution of its X-ray binary population and that the profile of L(sub x) with redshift can both serve as a diagnostic probe of the Star Formation Rate (SFR) profile and constrain evolutionary models for X-ray binaries. We update our previous work using a suite of more recently developed SFR profiles that span the currently plausible range. The first Chandra deep imaging results on L(sub x)-evolution are beginning to probe the SFR profile of bright spirals and the early results are consistent with predictions based on current SFR models. Using these new SFR profiles the resolution of the "birthrate problem" of lowmass X-ray binaries (LMXBs) and recycled, millisecond pulsars in terms of an evolving global SFR is more complete. We also discuss the possible impact of the variations in the SFR profile of individual galaxies.

  8. Long-term cycles in cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Priedhorsky, W. C.; Holt, S. S.

    1987-01-01

    Data on long-term cycles in galactic X-ray sources are reviewed, and classes of variations are identified including precessional activity, recurrent outbursts in Population II sources, and Be/neutron star flare cycles. Cycles of 30-300 days have been found in LMC X-4, Her X-1, SS433, and Cyg X-1 which represent cyclic variations in both the inner and outer parts of the accretion disk. Quasi-periodic cycles with periods ranging from 1/2 to 2 years have been noted in several low-mass X-ray binaries. It is suggested that periodic outbursts in the Be/neutron star systems may result from variable mass transfer in a wide eccentric orbit.

  9. Cosmic X-ray telescope for ARIES rocket observations

    NASA Technical Reports Server (NTRS)

    Catura, R. C.; Acton, L. W.; Berthelsdorf, R.; Culhane, J. L.; Sanford, P. W.; Franks, A.

    1979-01-01

    A rocket-borne Wolter Type I X-ray telescope having a focal length of 2.3m, an entrance aperture of 66cm and a geometrical area of 380cm2 is nearing completion. The telescope mirrors are formed by diamond turning their figures into forged aluminum substrates of 5083 alloy. These diamond-turned substrates are subsequently plated with a thin coating of electroless nickel and polished to obtain the final X-ray reflecting surfaces. Details of the rocket payload, the X-ray telescope, its calculated response and the experience gained in selecting the mirror substrate alloy are discussed and the current status of the telescope is reviewed.

  10. X-RAY BINARY EVOLUTION ACROSS COSMIC TIME

    SciTech Connect

    Fragos, T.; Zezas, A.; Lehmer, B.; Tzanavaris, P.; Tremmel, M.; Basu-Zych, A.; Hornschemeier, A.; Jenkins, L.; Ptak, A.; Belczynski, K.; Kalogera, V.

    2013-02-10

    High-redshift galaxies permit the study of the formation and evolution of X-ray binary (XRB) populations on cosmological timescales, probing a wide range of metallicities and star formation rates (SFRs). In this paper, we present results from a large-scale population synthesis study that models the XRB populations from the first galaxies of the universe until today. We use as input to our modeling the Millennium II cosmological simulation and the updated semi-analytic galaxy catalog by Guo et al. to self-consistently account for the star formation history and metallicity evolution of the universe. Our modeling, which is constrained by the observed X-ray properties of local galaxies, gives predictions about the global scaling of emission from XRB populations with properties such as SFR and stellar mass, and the evolution of these relations with redshift. Our simulations show that the X-ray luminosity density (X-ray luminosity per unit volume) from XRBs in our universe today is dominated by low-mass XRBs, and it is only at z {approx}> 2.5 that high-mass XRBs become dominant. We also find that there is a delay of {approx}1.1 Gyr between the peak of X-ray emissivity from low-mass XRBs (at z {approx} 2.1) and the peak of SFR density (at z {approx} 3.1). The peak of the X-ray luminosity from high-mass XRBs (at z {approx} 3.9) happens {approx}0.8 Gyr before the peak of the SFR density, which is due to the metallicity evolution of the universe.

  11. Hard X-ray irradiation of cosmic silicate analogs: structural evolution and astrophysical implications

    NASA Astrophysics Data System (ADS)

    Gavilan, L.; Jäger, C.; Simionovici, A.; Lemaire, J. L.; Sabri, T.; Foy, E.; Yagoubi, S.; Henning, T.; Salomon, D.; Martinez-Criado, G.

    2016-03-01

    Context. Protoplanetary disks, interstellar clouds, and active galactic nuclei contain X-ray-dominated regions. X-rays interact with the dust and gas present in such environments. While a few laboratory X-ray irradiation experiments have been performed on ices, X-ray irradiation experiments on bare cosmic dust analogs have been scarce up to now. Aims: Our goal is to study the effects of hard X-rays on cosmic dust analogs via in situ X-ray diffraction. By using a hard X-ray synchrotron nanobeam, we seek to simulate cumulative X-ray exposure on dust grains during their lifetime in these astrophysical environments and provide an upper limit on the effect of hard X-rays on dust grain structure. Methods: We prepared enstatite (MgSiO3) nanograins, which are analogs to cosmic silicates, via the melting-quenching technique. These amorphous grains were then annealed to obtain polycrystalline grains. These were characterized via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) before irradiation. Powder samples were prepared in X-ray transparent substrates and were irradiated with hard X-rays nanobeams (29.4 keV) provided by beamline ID16B of the European Synchrotron Radiation Facility (Grenoble). X-ray diffraction images were recorded in transmission mode, and the ensuing diffractograms were analyzed as a function of the total X-ray exposure time. Results: We detected the amorphization of polycrystalline silicates embedded in an organic matrix after an accumulated X-ray exposure of 6.4 × 1027 eV cm-2. Pure crystalline silicate grains (without resin) do not exhibit amorphization. None of the amorphous silicate samples (pure and embedded in resin) underwent crystallization. We analyze the evolution of the polycrystalline sample embedded in an organic matrix as a function of X-ray exposure. Conclusions: Loss of diffraction peak intensity, peak broadening, and the disappearance of discrete spots and arcs reveal the amorphization

  12. Spectacular X-ray Jet Points Toward Cosmic Energy Booster

    NASA Astrophysics Data System (ADS)

    2000-06-01

    NASA's Chandra X-ray Observatory has revealed a spectacular luminous spike of X rays that emanates from the vicinity of a giant black hole in the center of the radio galaxy Pictor A. The spike, or jet, is due to a beam of particles that streaks across hundreds of thousands of light years of intergalactic space toward a brilliant X-ray hot spot that marks its end point. Pictor A Image Press Image and Caption The hot spot is at least 800 thousand light years (8 times the diameter of our Milky Way galaxy) away from where the jet originates. It is thought to represent the advancing head of the jet, which brightens conspicuously where it plows into the tenuous gas of intergalactic space. The jet, powered by the giant black hole, originates from a region of space no bigger than the solar system. "Both the brightness and the spectrum of the X rays are very different from what theory predicts," Professor Andrew Wilson reported today at the 196th national meeting of the American Astronomical Society in Rochester, New York. Wilson, of the University of Maryland, College Park, along with Dr. Patrick Shopbell and Dr. Andrew Young, also of the University of Maryland, are submitting an article on this research to the Astrophysical Journal. "The Chandra observations are telling us that something out there is producing many more high-energy particles than we expected," said Wilson. One possible explanation for the X rays is that shock waves along the side and head of the X-ray jet are accelerating electrons and possibly protons to speeds close to that of light. In the process the electrons are boosted to energies as high as 100 million times their own rest mass energy. These electrons lose their energy rapidly as they produce X rays, so this could be the first direct evidence of this process so far outside a galaxy. The hot spot has been seen with optical and radio telescopes. Radio telescopes have also observed a faint jet. Jets are thought to be produced by the extreme

  13. Spectroscopic analysis of solar and cosmic X-ray spectra. 1: The nature of cosmic X-ray spectra and proposed analytical techniques

    NASA Technical Reports Server (NTRS)

    Walker, A. B. C., Jr.

    1975-01-01

    Techniques for the study of the solar corona are reviewed as an introduction to a discussion of modifications required for the study of cosmic sources. Spectroscopic analysis of individual sources and the interstellar medium is considered. The latter was studied via analysis of its effect on the spectra of selected individual sources. The effects of various characteristics of the ISM, including the presence of grains, molecules, and ionization, are first discussed, and the development of ISM models is described. The expected spectral structure of individual cosmic sources is then reviewed with emphasis on supernovae remnants and binary X-ray sources. The observational and analytical requirements imposed by the characteristics of these sources are identified, and prospects for the analysis of abundances and the study of physical parameters within them are assessed. Prospects for the spectroscopic study of other classes of X-ray sources are also discussed.

  14. K-alpha X-rays from cosmic ray oxygen. [Detection and calculation of equilibrium charge fractions

    NASA Technical Reports Server (NTRS)

    Pravdo, S. H.; Boldt, E. A.

    1975-01-01

    Equilibrium charge fractions are calculated for subrelativistic cosmic ray oxygen ions in the interstellar medium. These are used to determine the expected flux of K-alpha rays arising from atomic processes for a number of different postulated interstellar oxygen spectra. Relating these results to the diffuse X-ray background measured at the appropriate energy level suggests an observable line feature. If the flux of low energy cosmic ray oxygen is sufficiently large, K-alpha X-ray line emission from these nuclei will comprise a significant fraction of the total diffuse flux at approximately 0.6 keV. A satellite borne detector with a resolution greater than 30 percent could observe this feature if the subrelativistic interstellar cosmic ray oxygen spectrum is as large as certain theoretical estimates expressed in the text.

  15. The cosmic X-ray experiment aboard HEAO-1

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.; Bolt, E.; Holt, S.; Serlemitsos, P. J.; Garmire, G.; Agrawal, P.; Reigler, G.; Bowyer, C. S.; Lampton, M.

    1978-01-01

    The HEAO-1 A-2 experiment, designed to study the large scale structure of the galaxy and the universe at X-ray energies is described. The instrument consists of six gas proportional counters of three types nominally covering the energy ranges of 0.15-3 keV, 1.2-20 keV, and 2.5-60 keV. The two low energy detectors have about 400 sq cm open area each while the four others have about 800 sq cm each. Dual field of view collimators allow the unambiguous determination of instrument internal background and diffuse X-ray brightness. Instrument characteristics and early performance are discussed.

  16. Discriminating cosmic muons and X-rays based on rise time using a GEM detector

    NASA Astrophysics Data System (ADS)

    Wu, Hui-Yin; Zhao, Sheng-Ying; Wang, Xiao-Dong; Zhang, Xian-Ming; Qi, Hui-Rong; Zhang, Wei; Wu, Ke-Yan; Hu, Bi-Tao; Zhang, Yi

    2016-08-01

    Gas electron multiplier (GEM) detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold. Supported by National Natural Science Foundation of China (11135002, 11275235, 11405077, 11575073)

  17. Spherical crystal imaging spectrometer (SCIS) for cosmic x-ray spectroscopy.

    PubMed

    Schnopper, H W; Taylor, P O

    1980-10-01

    The application of a spherically bent crystal x-ray spectrometer to cosmic x-ray problems is discussed. This is the only geometry whose diffraction properties are preserved under all rotations of the spacecraft. The combination of Bragg reflection and spherical aberration provides for stigmatic imaging of extended sources and minimum spatial and/or spectral resolution loss arising from source extent and spacecraft pointing errors. The sensitivity of the instrument is discussed in the context of a Spacelab mission. PMID:20234612

  18. Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

    SciTech Connect

    Inoue, Yoshiyuki; Murase, Kohta; Madejski, Grzegorz M.; Uchiyama, Yasunobu

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10-12 erg/cm2/s-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  19. Properties of a transmission grating behind a grazing incidence telescope for cosmic x-ray spectroscopy.

    PubMed

    Beuermann, K P; Lenzen, R; Bräuninger, H

    1977-05-01

    Third-order aberrations are discussed of a transmission grating positioned behind a Wolter type I telescope, using Fermat's principle. We describe the conditions required to obtain a coma-free grating. The performance of a grating spectrometer for cosmic x-ray spectroscopy is discussed in some detail. PMID:20168712

  20. The cosmic X-ray background-IRAS galaxy correlation and the local X-ray volume emissivity

    NASA Technical Reports Server (NTRS)

    Miyaji, Takamitsu; Lahav, Ofer; Jahoda, Keith; Boldt, Elihu

    1994-01-01

    We have cross-correlated the galaxies from the IRAS 2 Jy redshift survey sample and the 0.7 Jy projected sample with the all-sky cosmic X-ray background (CXB) map obtained from the High Energy Astronomy Observatory (HEAO) 1 A-2 experiment. We have detected a significant correlation signal between surface density of IRAS galaxies and the X-ray background intensity, with W(sub xg) = (mean value of ((delta I)(delta N)))/(mean value of I)(mean value of N)) of several times 10(exp -3). While this correlation signal has a significant implication for the contribution of the local universe to the hard (E greater than 2 keV) X-ray background, its interpretation is model-dependent. We have developed a formulation to model the cross-correlation between CXB surface brightness and galaxy counts. This includes the effects of source clustering and the X-ray-far-infrared luminosity correlation. Using an X-ray flux-limited sample of active galactic nuclei (AGNs), which has IRAS 60 micrometer measurements, we have estimated the contribution of the AGN component to the observed CXB-IRAS galaxy count correlations in order to see whether there is an excess component, i.e., contribution from low X-ray luminosity sources. We have applied both the analytical approach and Monte Carlo simulations for the estimations. Our estimate of the local X-ray volume emissivity in the 2-10 keV band is rho(sub x) approximately = (4.3 +/- 1.2) x 10(exp 38) h(sub 50) ergs/s/cu Mpc, consistent with the value expected from the luminosity function of AGNs alone. This sets a limit to the local volume emissivity from lower luminosity sources (e.g., star-forming galaxies, low-ionization nuclear emission-line regions (LINERs)) to rho(sub x) less than or approximately = 2 x 10(exp 38) h(sub 50) ergs/s/cu Mpc.

  1. Cosmic ray/Soft X-ray background relationship from July 1968 to June 1987

    NASA Astrophysics Data System (ADS)

    Jakimiec, M.; Antalova, A.; Storini, M.

    2000-10-01

    The cross-correlation technique has been applied to obtain quantitative information on the short-term relation between the intensity of the nucleonic component of galactic cosmic rays (CR), as recorded by the Calgary neutron monitor, and the solar soft X-ray background (XBG), measured by satellites. The data consisted of uninterrupted daily sequences from July 1968 to June 1987. Using the 12-month basic (b_i), detrended (d_i), the running mean (m_i(n)) and the residual sequences (r_i(n)), where n = 3, 7, 15, 27 days and i = 1,..., 19, the consecutive CR/XBG cross-correlation functions (ccf-s) were computed with a time lag ranging from -2 to +60 days. In 13 cases out of the 19 d_i sequences, a statistically significant anticorrelation was found in the first minimum (for a lag shorter than or equal to 10 days). The m_i and the r_i sequences helped to identify fluctuations on different time scales. In Jakimiec, Antalova and Storini (1999) results for the period July 1968-June 1980 were used to underline differences and analogies between the descending phase of solar activity cycle n. 20 and the ascending phase of solar activity cycle n. 21, i.e., one complete heliomagnetic semicycle. Here we mainly compared the relationship between both parameters during two consecutive descending phases of cycle n. 20 with the one of cycle n. 21.

  2. A search for the dipole anisotropy of the Cosmic x ray background. Thesis

    NASA Technical Reports Server (NTRS)

    Evans, Tom

    1992-01-01

    X ray data was analyzed which was obtained by the HEAO-1 A2 satellite in order to look for large scale structure in the Cosmic X ray Background. The dipole moment of the x ray background is deltaI/I = (1.87 + or - .34)x 10(exp -2) in a direction, declination = 3.6 + or - 9.4 deg and right ascension = 15.9 + or - .2 hr. This implies a velocity of the Earth with respect to the background of 409.2 + or - 74.4 km/s in the same direction. Comparatively, measurements of the dipole anisotropy of the Cosmic Microwave Background imply a velocity of 369.2 + or - 4 km/s in a direction, declination = 6 + or - 1 deg and right ascension = 11.2 + or - .1 hr. Quoted errors are statistical only. The disparity between the velocities of the x ray dipole and microwave dipole may be due to residual structure in the x ray sky or as yet undiscovered systematic errors.

  3. Correlations Between the Cosmic X-Ray and Microwave Backgrounds: Constraints on a Cosmological Constant

    NASA Technical Reports Server (NTRS)

    Boughn, S. P.; Crittenden, R. G.; Turok, N. G.

    1998-01-01

    In universes with significant curvature or cosmological constant, cosmic microwave background (CMB) anisotropies are created very recently via the Rees-Sciama or integrated Sachs-Wolfe effects. This causes the CMB anisotropies to become partially correlated with the local matter density (z less than 4). We examine the prospects of using the hard (2- 10 keV) X-ray background as a probe of the local density and the measured correlation between the HEAO1 A2 X-ray survey and the 4-year COBE-DMR map to obtain a constraint on the cosmological constant. The 95% confidence level upper limit on the cosmological constant is OMega(sub Lambda) less than or equal to 0.5, assuming that the observed fluctuations in the X-ray map result entirely from large scale structure. (This would also imply that the X-rays trace matter with a bias factor of b(sub x) approx. = 5.6 Omega(sub m, sup 0.53)). This bound is weakened considerably if a large portion of the X-ray fluctuations arise from Poisson noise from unresolved sources. For example, if one assumes that the X-ray bias is b(sub x) = 2, then the 95% confidence level upper limit is weaker, Omega(sub Lambda) less than or equal to 0.7. More stringent limits should be attainable with data from the next generation of CMB and X-ray background maps.

  4. Cosmological Implications of the Effects of X-Ray Clusters on the Cosmic Microwave Background

    NASA Technical Reports Server (NTRS)

    Forman, William R.

    1996-01-01

    We have been carrying forward a program to confront X-ray observations of clusters and their evolution as derived from X-ray observatories with observations of the cosmic microwave background radiation (CMBR). In addition to the material covered in our previous reports (including three published papers), most recently we have explored the effects of a cosmological constant on the predicted Sunyaev-Zel'dovich effect from the ensemble of clusters. In this report we summarize that work from which a paper will be prepared.

  5. A preliminary design study for a cosmic X-ray spectrometer

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The results are described of theoretical and experimental investigations aimed at the development of a curved crystal cosmic X-ray spectrometer to be used at the focal plane of the large orbiting X-ray telescope on the third High Energy Astronomical Observatory. The effort was concentrated on the development of spectrometer concepts and their evaluation by theoretical analysis, computer simulation, and laboratory testing with breadboard arrangements of crystals and detectors. In addition, a computer-controlled facility for precision testing and evaluation of crystals in air and vacuum was constructed. A summary of research objectives and results is included.

  6. The Spectrum of the Cosmic X-ray Background Observed by RTXE/PCA

    NASA Technical Reports Server (NTRS)

    Revnivtsev, M.; Gilfanov, M.; Sunyaev, R.; Jahoda, K.; Markwardt, C.

    2004-01-01

    We have analyzed a large set of Rossi X-ray Timing Explorer/Proportional Counter Array (RXTE/PCA) scanning and slewing observations performed between April 1996 and March 1999. We obtained the 3-20 keV spectrum of the cosmic X-ray background (CXB) by subtracting Earth-occulted observations from observations of the X-ray sky at high galactic latitude and far away from sources. The sky coverage is approximately 22.6 x 10(exp 3) square degrees. The PCA spectrum of CXB in 3-20 keV energy band is adequately approximated by a single power law with photon index GAMMA approximately 1.4 and normalization at 1 keV approximately 9.5 phot/s/square centimeter/keV/sr. Instrumental background uncertainty precludes accurate RXTE/PCA measurements of the spectrum of cosmic X-ray background at energies above 15 keV and therefore we cannot detect the high energy cutoff observed by the High Energy Astronomical Observatory (HEAO)-1 A2 experiment. Deep observations of the 6 high latitude points used to model the PCA background provide a coarse measure of the spatial variation of the CXB. The CXB variations are consistent with a fixed spectral shape and variable normalization characterized by a fractional rms amplitude of approximately 7% on angular scales of approximately 1 square deg.

  7. Constraining the X-Ray and Cosmic-Ray Ionization Chemistry of the TW Hya Protoplanetary Disk: Evidence for a Sub-interstellar Cosmic-Ray Rate

    NASA Astrophysics Data System (ADS)

    Cleeves, L. Ilsedore; Bergin, Edwin A.; Qi, Chunhua; Adams, Fred C.; Öberg, Karin I.

    2015-02-01

    We present an observational and theoretical study of the primary ionizing agents (cosmic rays (CRs) and X-rays) in the TW Hya protoplanetary disk. We use a set of resolved and unresolved observations of molecular ions and other molecular species, encompassing 11 lines total, in concert with a grid of disk chemistry models. The molecular ion constraints comprise new data from the Submillimeter Array on HCO+, acquired at unprecedented spatial resolution, and data from the literature, including ALMA observations of N2H+. We vary the model incident CR flux and stellar X-ray spectra and find that TW Hya's HCO+ and N2H+ emission are best-fit by a moderately hard X-ray spectra, as would be expected during the "flaring" state of the star, and a low CR ionization rate, ζCR <~ 10-19 s-1. This low CR rate is the first indication of the presence of CR exclusion by winds and/or magnetic fields in an actively accreting T Tauri disk system. With this new constraint, our best-fit ionization structure predicts a low turbulence "dead-zone" extending from the inner edge of the disk out to 50-65 AU. This region coincides with an observed concentration of millimeter grains, and we propose that the inner region of TW Hya is a dust (and possibly planet) growth factory as predicted by previous theoretical work.

  8. Measuring the Cosmic X-ray Background With RXTE Using Lunar Occultation

    NASA Astrophysics Data System (ADS)

    Markwardt, Craig; Jahoda, K.; Marshall, F.; Strohmayer, T.; Swank, J.

    2011-09-01

    The Cosmic X-ray background (CXB) contains significant information about the energy content of the universe. However, the total X-ray background flux itself is still a matter of some controversy. A recent compilation of 10 CXB 2-10 keV flux measurements by Moretti et al. (2003) found statistical errors of 5%, with some values differing by up to 25%. Here we present preliminary results of a new technique to measure the X-ray background, using the dark side of the moon as an occulting shutter within the RXTE PCA field of view. This technique has the benefit of measuring the total X-ray background emission, rather than concentrating on the point-like sources. Observations were carefully designed to allow the moon to pass over the center of the PCA field of view, obscuring about 20% of the total field of view. Multiple observations throughout the year 2010, at different celestial locations, allow improved statistics and a measure of cosmic variance. In this work, we show the first results from this technique and compare to previous results, with the goal of achieving better than 5% statistical errors in the 2-10 keV band.

  9. Exploring Galaxy Halos and the Cosmic Web through X-Ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bregman, Joel; Anderson, Mike; Dai, Xinyu; Miller, Matt; Hodges-Kluck, Edmund

    2015-10-01

    About 90 of the metals produced in the universe and 50 of the baryons are unaccounted for through UV-IR and radio studies of stars and gas. This large amount of gas and metals likely lies in a hot phase 0.5-10E6 K and must be enriched to about 0.2-0.3 of the solar metallicity, so it should be a good absorber of X-rays in the resonance lines of common elements. X-ray absorption lines against background AGNs should show hot extended halos around galaxies out to the virial radius, if not beyond. The outer parts of galaxy groups and some cosmic filaments are other potential sources of absorption. For the Milky Way, high X-ray spectral resolution allows us to determine the dynamics of the hot halo, including the rotation as a function of radius as well as the accretion or outflow rate.

  10. Resolving the Cosmic X-ray Background with NuSTAR and Chandra

    NASA Astrophysics Data System (ADS)

    Hickox, Ryan C.

    2016-04-01

    Although its origin was long mysterious, the cosmic X-ray background (CXB) is now known to be primarily the sum of emission from large number of active galactic nuclei (AGN). With the advent of NuSTAR, the first focusing high-energy X-ray observatory, we can now directly identify the sources that contribute to the bulk of the CXB at energies > 10 keV where the CXB spectrum peaks. I will present an analysis using data from the NuSTAR extragalactic survey program in which we using stacking techniques to determine the fraction of the CXB that is produced by X-ray sources identified at softer energies by deep Chandra observations. These results provide important constraints on AGN synthesis models fo the CXB and point toward a further "missing" population of obscured AGN. This work is supported in part by NASA award NNX15AP24G.

  11. Quasi-stellar objects in the intergalactic medium: Source for the cosmic X-ray background

    SciTech Connect

    Sherman, R.D.

    1980-06-15

    QSOs are regarded as sources of both electromagnetic radiation and ejected matter that heat and ionize a dense intergalactic medium (IGM). Using current estimates of QSO luminosity, number density, evolution, and spectral index, we study three viable models: the diffuse cosmic X-ray background is (1) due entirely to thermal Bremsstrahlung of the IGM, (2) completely supplied by QSO X-radiation, (3) or a combination of both. The upper limits on an IGM fractional density with respect to closure are ..cap omega..=0.26, 0.24, and 0.21 for pure collisional, photo/collisional mixture, and pure photoionization, respectively. These calculations give emission spectra, Compton distortion of the cosmic microwave background, and optical depths to distant OSOs for comparison with relevant data.

  12. OT1_mpage_1: Star Formation in X-ray Absorbed QSOs through cosmic time

    NASA Astrophysics Data System (ADS)

    Page, M.

    2010-07-01

    The nature of the connection between the growth of a black hole via accretion and that of its host galaxy bulge via star formation remains a fundamental question in galaxy evolution. SCUBA/850micron observations of matched samples of high redshift X-ray absorbed and unabsorbed QSOs demonstrated that the X-ray absorbed QSO were far more likely to be detected suggesting that their host galaxies had very high star formation rates. This result implies that the z~2 X-ray absorbed QSO population are undergoing the transition from the main star forming phase and the QSO phase of a massive galaxy. Follow-up X-ray observations of the absorbed X-ray QSOs found that the X-ray absorption is due to an outflowing, ionized wind which is potentially the feedback invoked by theorists to terminate star formation in the host galaxy. However, no QSOs from the samples, X-ray absorbed or unabsorbed, were detected with SCUBA below z=1.5. We propose SPIRE and PACS observations of a sample of 10 X-ray absorbed QSOs in the 1cosmic epoch.

  13. Anatomy of a cosmic-ray neutrino source and the Cygnus X-3 system

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Harding, A. K.; Barnard, J. J.

    1985-01-01

    The effects of an intense beam of ultra-high energy cosmic rays from a compact object in the Cygnus X-3 binary system hitting the companion star, and of the subsequent production of secondary neutrinos, are examined. A maximum allowable beam luminosity of about 10 to the 42nd erg/s is found for a system containing a 1-10 solar mass main sequence target star. The proton beam must heat a relatively small area of the target star to satisfy observational constraints on the resulting stellar wind. With such a model, the neutrino to gamma-ray flux ratio of about 1000 can result from a combination of gamma-ray absorption and a large neutrino to gamma-ray duty cycle ratio. It is found that the high density of the atmosphere resulting from compression by the beam leads to pion cascading and a neutrino spectrum peaking at 1-10 GeV energies.

  14. CONSTRAINING THE X-RAY AND COSMIC-RAY IONIZATION CHEMISTRY OF THE TW Hya PROTOPLANETARY DISK: EVIDENCE FOR A SUB-INTERSTELLAR COSMIC-RAY RATE

    SciTech Connect

    Cleeves, L. Ilsedore; Bergin, Edwin A.; Adams, Fred C.; Qi, Chunhua; Öberg, Karin I.

    2015-02-01

    We present an observational and theoretical study of the primary ionizing agents (cosmic rays (CRs) and X-rays) in the TW Hya protoplanetary disk. We use a set of resolved and unresolved observations of molecular ions and other molecular species, encompassing 11 lines total, in concert with a grid of disk chemistry models. The molecular ion constraints comprise new data from the Submillimeter Array on HCO{sup +}, acquired at unprecedented spatial resolution, and data from the literature, including ALMA observations of N{sub 2}H{sup +}. We vary the model incident CR flux and stellar X-ray spectra and find that TW Hya's HCO{sup +} and N{sub 2}H{sup +} emission are best-fit by a moderately hard X-ray spectra, as would be expected during the ''flaring'' state of the star, and a low CR ionization rate, ζ{sub CR} ≲ 10{sup –19} s{sup –1}. This low CR rate is the first indication of the presence of CR exclusion by winds and/or magnetic fields in an actively accreting T Tauri disk system. With this new constraint, our best-fit ionization structure predicts a low turbulence ''dead-zone'' extending from the inner edge of the disk out to 50-65 AU. This region coincides with an observed concentration of millimeter grains, and we propose that the inner region of TW Hya is a dust (and possibly planet) growth factory as predicted by previous theoretical work.

  15. Goddard contributions to the Los Alamos Conference on Transient Cosmic Gamma and X-ray Sources

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Conference papers, covering the orgin and instrumentation for measuring the position of cosmic gamma ray bursts, are presented. Summaries cover gamma ray detectors, energy speectra, and the stellar super flare hypothesis.

  16. Laboratory studies on a spherically curved Bragg spectrometer for cosmic X-ray spectroscopy

    NASA Technical Reports Server (NTRS)

    Cantin, M.; Koch-Miramond, L.; Mougin, B.; Rocchia, R.

    1981-01-01

    A spherical array of twenty LiF 200 crystals was built to test the performances of a freestanding, self-focussing spherical crystal cosmic X-ray spectrometer. Measurements presently available show that the size of the image for a point source at infinite distance would be 3 mm (FWHM) along the focalisation axis and 2.1 mm (FWHM) along the dispersion axis. The mosaic spread on individual crystals is less than 0.1 degree. A slightly systematic deviation from the ideal bending (0.1 degree) is observed at the edges of most crystals and this appears to be the major limitation to spectrometer performance.

  17. Comptonization of X-rays by low-temperature electrons. [photon wavelength redistribution in cosmic sources

    NASA Technical Reports Server (NTRS)

    Illarionov, A.; Kallman, T.; Mccray, R.; Ross, R.

    1979-01-01

    A method is described for calculating the spectrum that results from the Compton scattering of a monochromatic source of X-rays by low-temperature electrons, both for initial-value relaxation problems and for steady-state spatial diffusion problems. The method gives an exact solution of the inital-value problem for evolution of the spectrum in an infinite homogeneous medium if Klein-Nishina corrections to the Thomson cross section are neglected. This, together with approximate solutions for problems in which Klein-Nishina corrections are significant and/or spatial diffusion occurs, shows spectral structure near the original photon wavelength that may be used to infer physical conditions in cosmic X-ray sources. Explicit results, shown for examples of time relaxation in an infinite medium and spatial diffusion through a uniform sphere, are compared with results obtained by Monte Carlo calculations and by solving the appropriate Fokker-Planck equation.

  18. A high resolution gas scintillation proportional counter for studying low energy cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Hamilton, T. T.; Hailey, C. J.; Ku, W. H.-M.; Novick, R.

    1980-01-01

    In recent years much effort has been devoted to the development of large area gas scintillation proportional counters (GSPCs) suitable for use in X-ray astronomy. The paper deals with a low-energy GSPC for use in detecting sub-keV X-rays from cosmic sources. This instrument has a measured energy resolution of 85 eV (FWHM) at 149 eV over a sensitive area of 5 sq cm. The development of imaging capability for this instrument is discussed. Tests are performed on the feasibility of using an arrangement of several phototubes placed adjacent to one another to determine event locations in a large flat counter. A simple prototype has been constructed and successfully operated.

  19. Cosmic ray isotopes

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1973-01-01

    The isotopic composition of cosmic rays is studied in order to develop the relationship between cosmic rays and stellar processes. Cross section and model calculations are reported on isotopes of H, He, Be, Al and Fe. Satellite instrument measuring techniques separate only the isotopes of the lighter elements.

  20. The Nature of the Unresolved Extragalactic Cosmic Soft X-Ray Background

    NASA Technical Reports Server (NTRS)

    Cappelluti, N.; Ranalli, P.; Roncarelli, M.; Arevalo, P.; Zamorani, G.; Comastri, A.; Gilli, R.; Rovilos, E.; Vignali, C.; Allevato, V.; Finoguenov, A.; Miyaji, T.; Nicastro, F.; Georgantopoulos, I.; Kashlinsky, A.

    2013-01-01

    In this paper we investigate the power spectrum of the unresolved 0.5-2 keV cosmic X-ray background (CXB) with deep Chandra 4-Msec (Ms) observations in the Chandra Deep Field South (CDFS). We measured a signal that, on scales >30 arcsec, is significantly higher than the shot noise and is increasing with angular scale. We interpreted this signal as the joint contribution of clustered undetected sources like active galactic nuclei (AGN), galaxies and the intergalactic medium (IGM). The power of unresolved cosmic source fluctuations accounts for approximately 12 per cent of the 0.5-2 keV extragalactic CXB. Overall, our modelling predicts that approximately 20 per cent of the unresolved CXB flux is produced by low-luminosity AGN, approximately 25 per cent by galaxies and approximately 55 per cent by the IGM. We do not find any direct evidence of the so-called 'warm hot intergalactic medium' (i.e. matter with 10(exp 5) less than T less than 10(exp 7) K and density contrast delta less than 1000), but we estimated that it could produce about 1/7 of the unresolved CXB. We placed an upper limit on the space density of postulated X-ray-emitting early black holes at z greater than 7.5 and compared it with supermassive black hole evolution models.

  1. Cosmic-ray astrochemistry.

    PubMed

    Indriolo, Nick; McCall, Benjamin J

    2013-10-01

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

  2. Current and Prospective Constraints on Cosmic Acceleration using X-ray Galaxy Clusters and Supernovae

    NASA Astrophysics Data System (ADS)

    Rapetti, David A.; Allen, S. W.; Amin, M. A.; Blandford, R. D.

    2006-09-01

    We employ both a standard dynamical approach and a new kinematical approach to constrain cosmic acceleration using the three best available sets of redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements. The standard `dynamical' analysis employs the Friedmann equations and models dark energy as a fluid with an equation of state parameter, w. From a purely kinematical point of view, however, we can also construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q_0 and the cosmic jerk parameter, j(t). A convenient feature of this parameterization is that all LambdaCDM models have j(t)=1 (constant), which facilitates simple tests for departures from the LambdaCDM paradigm. We obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk j(t)=j, we measure q_0=-0.81+-0.14 and j=2.16+0.81-0.75. For a dynamical model with constant w we measure Omega_m=0.306+0.042-0.040 and w=-1.15+0.14-0.18. Both kinematical and dynamical results are consistent with LambdaCDM at the 1sigma level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. We argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible. Finally, we discuss the potential for future experiments including Constellation-X, which will constrain dark energy with comparable accuracy and in a beautifully complementary manner to the best other techniques available circa 2018.

  3. Chandra Resolves Cosmic X-ray Glow and Finds Mysterious New Sources

    NASA Astrophysics Data System (ADS)

    2000-01-01

    While taking a giant leap towards solving one of the greatest mysteries of X-ray astronomy, NASA's Chandra X-ray Observatory also may have revealed the most distant objects ever seen in the universe and discovered two puzzling new types of cosmic objects. Not bad for being on the job only five months. Chandra has resolved most of the X-ray background, a pervasive glow of X-rays throughout the universe, first discovered in the early days of space exploration. Before now, scientists have not been able to discern the background's origin, because no X-ray telescope until Chandra has had both the angular resolution and sensitivity to resolve it. "This is a major discovery," said Dr. Alan Bunner, Director of NASA's Structure andEvolution of the universe science theme. "Since it was first observed thirty-seven years ago, understanding the source of the X-ray background has been aHoly Grail of X-ray astronomy. Now, it is within reach." The results of the observation will be discussed today at the 195th national meeting of the American Astronomical Society in Atlanta, Georgia. An article describing this work has been submitted to the journal Nature by Dr. Richard Mushotzky, of NASA Goddard Space Flight Center, Greenbelt, Md., Drs. Lennox Cowie and Amy Barger at the University of Hawaii, Honolulu, and Dr. Keith Arnaud of the University of Maryland, College Park. "We are all very excited by this finding," said Mushotzky. "The resolution of most of the hard X-ray background during the first few months of the Chandra mission is a tribute to the power of this observatory and bodes extremely well for its scientific future," Scientists have known about the X-ray glow, called the X-ray background, since the dawn of X-ray astronomy in the early 1960s. They have been unable to discern its origin, however, for no X-ray telescope until Chandra has had both the angular resolution and sensitivity to resolve it. The German-led ROSAT mission, now completed, resolved much of the lower

  4. Eleventh European Cosmic Ray Symposium

    NASA Astrophysics Data System (ADS)

    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.

  5. Spectral-luminosity evolution of active galactic nuclei and the cosmic X- and gamma ray background

    NASA Technical Reports Server (NTRS)

    Leiter, Darryl; Boldt, Elihu

    1992-01-01

    Coherent electromagnetic dynamo acceleration processes, which act on charge particles within the context of black hole accretion disk scenarios, are generally regarded as the underlying central power source for active galactic nuclei (AGN). If the precursor active galaxies (PAG) for such AGN are formed at high redshift and contain initial seed black holes with mass approximately equal to 10(exp 4) solar masses, then the Eddington limited X-ray radiation emitted during their lifetime will undergo the phenomenon of 'spectral-luminosity evolution'. When accretion disks are first formed at the onset of galaxy formation the accretion rate occurs at very high values of luminosity/size compactness parameter L/R greater than 10(exp 30) erg/cm-sec. In the absence of extended structure, such high values of L/R generate dynamic constraints which suppress coherent, black hole/accretion disk dynamo particle acceleration processes. This inhibits nonthermal radiation processes and causes the spectrum of X-radiation emitted by PAG to be predominantly thermal. A superposition of PAG sources at z is greater than or equal to 6 can account for the residual cosmic X-ray background (CXB) obtained from the total CXB after subtraction of foreground AGN sources associated with present epoch Seyfert galaxies. The manner in which the PAG undergo spectral-luminosity evolution into Seyfert galaxies is investigated.

  6. Cerenkov x total energy telescopes for the study of the mass composition of cosmic rays

    NASA Technical Reports Server (NTRS)

    Webber, W. R.

    1980-01-01

    The mass resolution attainable with cosmic ray telescopes employing Cerenkov counters for velocity measurement was examined. It is shown that in most cases, the limiting mass resolution is determined by the resolution of the Cerenkov counter. The resolution achieved in the UNH telescope flown on a balloon in 1977 is studied as a function of charge and energy. This telescope determines the mass using the Cerenkov x total energy technique. It is shown that the mass resolution for heavier nuclei can be accurately predicted using the response of the Cerenkov counter to sea level mu-mesons. The actual in flight resolution for heavier nuclei, including broadening effects, may be predicted using the beta = 1 Cerenkov distributions, and independently by studying the distribution function of the differences of the two banks of photomultipliers employed on each Cerenkov counter.

  7. Results of investigation of muon fluxes of superhigh energy cosmic rays with X-ray emulsion chambers

    NASA Technical Reports Server (NTRS)

    Ivanenko, I. P.; Ivanova, M. A.; Kuzmichev, L. A.; Ilyina, N. P.; Mandritskaya, K. V.; Osipova, E. A.; Rakobolskaya, I. V.; Zatsepin, G. T.

    1985-01-01

    The overall data from the investigation of the cosmic ray muon flux in the range of zenith angles (0-90) deg within the energy range (3.5 to 5.0) TeV is presented. The exposure of large X-ray emulsion chambers underground was 1200 tons. year. The data were processe using the method which was applied in the experiment Pamir and differred from the earlier applied one. The obtained value of a slope power index of the differential energy spectrum of the global muon flux is =3.7 that corresponds to the slope of the pion generation differential spectrum, gamma sub PI = 2.75 + or - .04. The analysis of the muon zenith-angular distribution showed that the contribution of rapid generation muons in the total muon flux agree the best with the value .2% and less with .7% at a 90% reliability level.

  8. Optically thick X-ray transfer - The shell game. [transmission through gas surrounding cosmic x ray source

    NASA Technical Reports Server (NTRS)

    Langer, S. H.; Ross, R. R.; Mccray, R.

    1978-01-01

    This paper investigates the radiative transfer of X-rays through a shell that is optically thick to Compton scattering, surrounding a point source of continuum X-rays. The emission and absorption of X-rays due to K-shell transitions of iron are included. The calculations are done in two entirely independent ways: by Monte Carlo simulation and by solving a Fokker-Planck diffusion equation. The emergent spectra agree very well for Thomson depths of at least about 2. The validity is confirmed of the modification to the Fokker-Planck equation of Kompaneets (1957) that is required when the photon energy is large compared with the average thermal energy of the electrons. A procedure is also developed for treating models of compact X-ray sources consisting of incomplete shells.

  9. Cosmic Ray Dosimetry

    NASA Astrophysics Data System (ADS)

    Si Belkhir, F.; Attallah, R.

    2010-10-01

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

  10. The spectral archive of cosmic X-ray sources observed by the Einstein Observatory Focal Plane Crystal Spectrometer

    NASA Technical Reports Server (NTRS)

    Lum, Kenneth S. K.; Canizares, Claude R.; Clark, George W.; Coyne, Joan M.; Markert, Thomas H.; Saez, Pablo J.; Schattenburg, Mark L.; Winkler, P. F.

    1992-01-01

    The Einstein Observatory Focal Plane Crystal Spectrometer (FPCS) used the technique of Bragg spectroscopy to study cosmic X-ray sources in the 0.2-3 keV energy range. The high spectral resolving power (E/Delta-E is approximately equal to 100-1000) of this instrument allowed it to resolve closely spaced lines and study the structure of individual features in the spectra of 41 cosmic X-ray sources. An archival summary of the results is presented as a concise record the FPCS observations and a source of information for future analysis by the general astrophysics community. For each observation, the instrument configuration, background rate, X-ray flux or upper limit within the energy band observed, and spectral histograms are given. Examples of the contributions the FPCS observations have made to the understanding of the objects observed are discussed.

  11. Cosmic Evolution of X-ray Binary Populations: Probes of Changing Chemistry and Aging Stellar Populations in the Universe

    NASA Astrophysics Data System (ADS)

    Lehmer, Bret; Basu-Zych, Antara; Mineo, Stefano; Brandt, W. Niel; Eufrasio, Rafael T.; Fragos, Tassos; Hornschemeier, Ann E.; Luo, Bin; Xue, Yongquan; Bauer, Franz E.; Gilfanov, Marat; Kalogera, Vassiliki; Ranalli, Piero; Schneider, Donald P.; Shemmer, Ohad; Tozzi, Paolo; Trump, Jonathan; Vignali, Cristian; Wang, JunXian; Yukita, Mihoko; Zezas, Andreas

    2016-01-01

    The 2-10 keV emission from normal galaxies is dominated by X-ray binary (XRB) populations. The formation of XRBs is sensitive to galaxy properties like stellar age and metallicity---properties that have evolved significantly in the broader galaxy population throughout cosmic history. The 6 Ms Chandra Deep Field-South (CDF-S) allows us to study how XRB emission has evolved over a significant fraction of cosmic history (since z ~ 4), without significant contamination from AGN. Using constraints from the CDF-S, I will show that the X-ray emission from normal galaxies from z = 0-7 depends not only on star-formation rate (SFR), but also on stellar mass (M) and redshift. Our analysis shows the that low-mass X-ray binary emission scales with stellar mass and evolves as LX(LMXB)/M ~ (1+z)^3, and high-mass X-ray binaries scale with SFR and evolve as LX(HMXB)/SFR ~ (1+z), consistent with predictions from population synthesis models, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. These findings have important implications for the X-ray emission from young, low-metallicity galaxies at high redshift, which are likely to be more X-ray luminous per SFR and play a significant role in the heating of the intergalactic medium.

  12. Supernova and cosmic rays

    NASA Technical Reports Server (NTRS)

    Wefel, J. P.

    1981-01-01

    A general overview of supernova astronomy is presented, followed by a discussion of the relationship between SN and galactic cosmic rays. Pre-supernova evolution is traced to core collapse, explosion, and mass ejection. The two types of SN light curves are discussed in terms of their causes, and the different nucleosynthetic processes inside SNs are reviewed. Physical events in SN remnants are discussed. The three main connections between cosmic rays and SNs, the energy requirement, the acceleration mechanism, and the detailed composition of CR, are detailed.

  13. Galactic cosmic rays

    NASA Astrophysics Data System (ADS)

    Blasi, Pasquale

    2015-12-01

    The multi-facet nature of the origin of cosmic rays is such that some of the problems currently met in our path to describing available data are due to oversimplified models of CR acceleration and transport, and others to lack of knowledge of the physical processes at work in certain conditions. On the other hand, the phenomenology of cosmic rays, as arising from better observations, is getting so rich that it makes sense to try to distinguish the problems that derive from too simple views of Nature and those that are challenging the very foundations of the existing paradigms. Here I will briefly discuss some of these issues.

  14. Cosmic rays from cosmic strings with condensates

    SciTech Connect

    Vachaspati, Tanmay

    2010-02-15

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

  15. Discovery of cosmic rays

    NASA Astrophysics Data System (ADS)

    Carlson, Per

    2013-02-01

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

  16. Soft X-ray excess in the Coma cluster from a Cosmic Axion Background

    NASA Astrophysics Data System (ADS)

    Angus, Stephen; Conlon, Joseph P.; Marsh, M. C. David; Powell, Andrew J.; Witkowski, Lukas T.

    2014-09-01

    We show that the soft X-ray excess in the Coma cluster can be explained by a cosmic background of relativistic axion-like particles (ALPs) converting into photons in the cluster magnetic field. We provide a detailed self-contained review of the cluster soft X-ray excess, the proposed astrophysical explanations and the problems they face, and explain how a 0.1- 1 keV axion background naturally arises at reheating in many string theory models of the early universe. We study the morphology of the soft excess by numerically propagating axions through stochastic, multi-scale magnetic field models that are consistent with observations of Faraday rotation measures from Coma. By comparing to ROSAT observations of the 0.2- 0.4 keV soft excess, we find that the overall excess luminosity is easily reproduced for gaγγ ~ 2 × 10-13 Ge -1. The resulting morphology is highly sensitive to the magnetic field power spectrum. For Gaussian magnetic field models, the observed soft excess morphology prefers magnetic field spectra with most power in coherence lengths on Script O(3 kpc) scales over those with most power on Script O(12 kpc) scales. Within this scenario, we bound the mean energy of the axion background to 50 eVlesssim langle Ea rangle lesssim 250 eV, the axion mass to ma lesssim 10-12 eV, and derive a lower bound on the axion-photon coupling gaγγ gtrsim √(0.5/Δ Neff) 1.4 × 10-13 Ge -1.

  17. Mildly obscured active galaxies and the cosmic X-ray background

    NASA Astrophysics Data System (ADS)

    Esposito, V.; Walter, R.

    2016-05-01

    Context. The diffuse cosmic X-ray background (CXB) is the sum of the emission of discrete sources, mostly massive black-holes accreting matter in active galactic nuclei (AGN). The CXB spectrum differs from the integration of the spectra of individual sources, calling for a large population, undetected so far, of strongly obscured Compton-thick AGN. Such objects are predicted by unified models, which attribute most of the AGN diversity to their inclination on the line of sight, and play an important role for the understanding of the growth of black holes in the early Universe. Aims: The percentage of strongly obscured Compton-thick AGN at low redshift can be derived from the observed CXB spectrum, if we assume AGN spectral templates and luminosity functions. Methods: We show that high signal-to-noise stacked hard X-ray spectra, derived from more than a billion seconds of effective exposure time with the Swift/BAT instrument, imply that mildly obscured Compton-thin AGN feature a strong reflection and contribute massively to the CXB. Results: A population of Compton-thick AGN larger than that which is effectively detected is not required to reproduce the CXB spectrum, since no more than 6% of the CXB flux can be attributed to them. The stronger reflection observed in mildly obscured AGN suggests that the covering factor of the gas and dust surrounding their central engines is a key factor in shaping their appearance. These mildly obscured AGN are easier to study at high redshift than Compton-thick sources are.

  18. Soft X-ray excess in the Coma cluster from a Cosmic Axion Background

    SciTech Connect

    Angus, Stephen; Conlon, Joseph P.; Marsh, M.C. David; Powell, Andrew J.; Witkowski, Lukas T. E-mail: j.conlon1@physics.ox.ac.uk E-mail: andrew.powell2@physics.ox.ac.uk

    2014-09-01

    We show that the soft X-ray excess in the Coma cluster can be explained by a cosmic background of relativistic axion-like particles (ALPs) converting into photons in the cluster magnetic field. We provide a detailed self-contained review of the cluster soft X-ray excess, the proposed astrophysical explanations and the problems they face, and explain how a 0.1- 1 keV axion background naturally arises at reheating in many string theory models of the early universe. We study the morphology of the soft excess by numerically propagating axions through stochastic, multi-scale magnetic field models that are consistent with observations of Faraday rotation measures from Coma. By comparing to ROSAT observations of the 0.2- 0.4 keV soft excess, we find that the overall excess luminosity is easily reproduced for g{sub aγγ} ∼ 2 × 10{sup -13} Ge {sup -1}. The resulting morphology is highly sensitive to the magnetic field power spectrum. For Gaussian magnetic field models, the observed soft excess morphology prefers magnetic field spectra with most power in coherence lengths on O(3 kpc) scales over those with most power on O(12 kpc) scales. Within this scenario, we bound the mean energy of the axion background to 50 eV∼< ( E{sub a} ) ∼< 250 eV, the axion mass to m{sub a} ∼< 10{sup -12} eV, and derive a lower bound on the axion-photon coupling g{sub aγγ} ∼> √(0.5/Δ N{sub eff}) 1.4 × 10{sup -13} Ge {sup -1}.

  19. Cosmic ray antiprotons from nearby cosmic accelerators

    NASA Astrophysics Data System (ADS)

    Joshi, Jagdish C.; Gupta, Nayantara

    2015-05-01

    The antiproton flux measured by PAMELA experiment might have originated from Galactic sources of cosmic rays. These antiprotons are expected to be produced in the interactions of cosmic ray protons and nuclei with cold protons. Gamma rays are also produced in similar interactions inside some of the cosmic accelerators. We consider a few nearby supernova remnants observed by Fermi LAT. Many of them are associated with molecular clouds. Gamma rays have been detected from these sources which most likely originate in decay of neutral pions produced in hadronic interactions. The observed gamma ray fluxes from these SNRs are used to find out their contributions to the observed diffuse cosmic ray antiproton flux near the earth.

  20. Chandra Discovers X-Ray Ring Around Cosmic Powerhouse in Crab Nebula

    NASA Astrophysics Data System (ADS)

    1999-09-01

    After barely two months in space, NASA's Chandra X-ray Observatory has taken a stunning image of the Crab Nebula, the spectacular remains of a stellar explosion, and has revealed something never seen before: a brilliant ring around the nebula's heart. Combined with observations from the Hubble Space Telescope, the image provides important clues to the puzzle of how the cosmic "generator," a pulsing neutron star, energizes the nebula, which still glows brightly almost 1,000 years after the explosion. "The inner ring is unique," said Professor Jeff Hester of Arizona State University, Tempe, AZ. "It has never been seen before, and it should tell us a lot about how the energy from the pulsar gets into the nebula. It's like finding the transmission lines between the power plant and the light bulb." Professor Mal Ruderman of Columbia University, New York, NY, agreed. "The X-rays Chandra sees are the best tracer of where the energy is. With images such as these, we can directly diagnose what is going on." What is going on, according to Dr. Martin Weisskopf, Chandra Project Scientist from NASA's Marshall Space Flight Center, Huntsville, AL, is awesome. "The Crab pulsar is accelerating particles up to the speed of light and flinging them out into interstellar space at an incredible rate." The image shows tilted rings or waves of high-energy particles that appear to have been flung outward over the distance of a light year from the central star, and high-energy jets of particles blasting away from the neutron star in a direction perpendicular to the spiral. Hubble Space Telescope images have shown moving knots and wisps around the neutron star, and previous X-ray images have shown the outer parts of the jet and hinted at the ring structure. With Chandra's exceptional resolution, the jet can be traced all the way in to the neutron star, and the ring pattern clearly appears. The image was made with Chandra's Advanced CCD Imaging Spectrometer and High Energy Transmission

  1. Galactic cosmic rays and nucleosynthesis

    SciTech Connect

    Kiener, Juergen

    2010-03-01

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

  2. Fine-pitch and thick-foil gas electron multipliers for cosmic x-ray polarimeters

    NASA Astrophysics Data System (ADS)

    Tamagawa, Toru; Hayato, Asami; Yamaguchi, Yorito; Hamagaki, Hideki; Hashimoto, Shigehira; Inuzuka, Masahide; Miyasaka, Hiromasa; Sakurai, Ikuya; Tokanai, Fuyuki; Makishima, Kazuo

    2006-06-01

    We have produced various gas electron multiplier foils (GEMs) by using laser etching technique for cosmic X-ray polarimeters. The finest structure GEM we have fabricated has 30 μm-diameter holes on a 50 μm-pitch. The effective gain of the GEM reaches around 5000 at the voltage of 570 V between electrodes. The gain is slightly higher than that of the CERN standard GEM with 70 μm-diameter holes on a 140 μm-pitch. We have fabricated GEMs with thickness of 100 μm which has two times thicker than the standard GEM. The effective gain of the thick-foil GEM is 104 at the applied voltage of 350 V per 50 μm of thickness. The gain is about two orders higher than that of the standard GEM. The remarkable characteristic of the thick-foil GEM is that the effective gain at the beginning of micro-discharge is quite improved. For fabricating the thick-foil GEMs, we have employed new material, liquid crystal polymer (LCP) which has little moisture absorption rate, as an insulator layer instead of polyimide. One of the thick-foil GEM we have fabricated has 8 μm copper layer in the middle of the 100 μm-thick insulator layer. The metal layer in the middle of the foil works as a field-shaper in the multiplication channels, though it slightly decreases the effective gain.

  3. Cosmic X-ray Physics: A Suborbital Investigation of the Diffuse X-ray Background Including Instrumentation Development

    NASA Astrophysics Data System (ADS)

    McCammon, Dan

    We propose an investigation to improve our understanding of the Galactic diffuse X-ray background. The ultimate purpose of this is to determine the role of hot phases of the interstellar medium in mediating stellar feedback in star formation, in transport of metals, and in determining the structure and evolution of the Galaxy. This work will involve a flight of an existing payload with small modifications in Woomera, South Australia, to observe the Galactic soft X-ray bulge and attempt to determine its nature and emission mechanisms. It will also involve the development of detectors capable of 1-2 eV FWHM energy resolution in the 100-400 eV range with the intent of obtaining a scientifically useful spectrum on a sounding rocket flight of the emission from one million degree gas in this energy range. This will require a total area of 1-2 cm^2 for the detector array. With the collaboration and advice of microwave experts at the Goddard Space Flight Center, we will fabricate and test waveguide-below-cutoff filters to provide the necessary attenuation of infrared radiation for these detectors while still allowing relatively good x- ray transmission below 300 eV. The detectors, filters, and flight experience with the detector readouts are all relevant to future NASA major missions. The filters would be particularly valuable in allowing thermal detectors (microcalorimeters) similar to those used here in the X-ray range to be applied to the EUV and vacuum ultraviolet, where they offer large potential gains over existing detectors. These investigations will provide the primary training for our graduate students, and will involve a substantial number of undergraduates.

  4. Cosmic Rays at Earth

    NASA Astrophysics Data System (ADS)

    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

  5. Galactic cosmic ray composition

    NASA Technical Reports Server (NTRS)

    Meyer, J. P.

    1986-01-01

    An assessment is given of the galactic cosmic ray source (GCRS) elemental composition and its correlation with first ionization potential. The isotopic composition of heavy nuclei; spallation cross sections; energy spectra of primary nuclei; electrons; positrons; local galactic reference abundances; comparison of solar energetic particles and solar coronal compositions; the hydrogen; lead; nitrogen; helium; and germanium deficiency problems; and the excess of elements are among the topics covered.

  6. Cosmic Rays in Thunderstorms

    NASA Astrophysics Data System (ADS)

    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)

  7. Cosmic ray modulation

    NASA Astrophysics Data System (ADS)

    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.

  8. X-Ray Ccds for Space Applications: Calibration, Radiation Hardness, and Use for Measuring the Spectrum of the Cosmic X-Ray Background

    NASA Astrophysics Data System (ADS)

    Gendreau, Keith Charles

    1995-01-01

    This thesis has two distinct components. One concerns the physics of the high energy resolution X-ray charge coupled devices (CCD) detectors used to measure the cosmic X-ray background (XRB) spectrum. The other involves the measurements and analysis of the XRB spectrum and instrumental background with these detectors on board the advanced satellite for cosmology and astrophysics (ASCA). The XRB has a soft component and a hard component divided at ~2 keV. The hard component is extremely isotropic, suggesting a cosmological origin. The soft component is extremely anisotropic. A galactic component most likely dominates the soft band with X-ray line emission due to a hot plasma surrounding the solar system. ASCA is one of the first of a class of missions designed to overlap the hard and soft X-ray bands. The X-ray CCD's energy resolution allows us to spectrally separate the galactic and cosmological components. Also, the resolution offers the ability to test several specific cosmological models which would make up the XRB. I have concentrated on models for the XRB origin which include active galactic nuclei (AGN) as principal components. I use ASCA data to put spectral constraints on the AGN synthesis model for the XRB. The instrumental portion of this thesis concerns the development and calibration of the X-ray CCDs. I designed, built and operated an X-ray calibration facility for these detectors. It makes use of a reflection grating spectrometer to measure absolute detection efficiency, characteristic absorption edge strengths, and spectral redistribution in the CCD response function. Part of my thesis research includes a study of radiation damage mechanisms in CCDs. This work revealed radiation damage-induced degradation in the spectral response to X-rays. It also uncovered systematic effects which affect both data analysis and CCD design. I have developed a model involving trap energy levels in the CCD band gap structure. These traps reduce the efficiency in which

  9. Relativistic heavy cosmic rays

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  10. Cosmic Rays Across the Universe

    NASA Astrophysics Data System (ADS)

    Gould Zweibel, Ellen

    2016-01-01

    Cosmic rays play an important role in the dynamics, energetics, and chemisry of gas inside and outside galaxies. It has long been recognized that gamma ray astronomy is a powerful probe of cosmic ray acceleration and propagation, and that gamma ray data, combined with other observations of cosmic rays and of the host medium and with modeling, can provide an integrated picture of cosmic rays and their environments. I will discuss the plasma physics underlying this picture, where it has been successful, and where issues remain.

  11. Ion Storage Ring Measurements of Low Temperature Dielectronic Recombination Rate Coefficients for Modeling X-Ray Photoionized Cosmic Plasmas

    NASA Technical Reports Server (NTRS)

    Savin, D. W.; Gwinner, G.; Schwalm, D.; Wolf, A.; Mueller, A.; Schippers, S.

    2002-01-01

    Low temperature dielectronic recombination (DR) is the dominant recombination mechanism for most ions in X-ray photoionized cosmic plasmas. Reliably modeling and interpreting spectra from these plasmas requires accurate low temperature DR rate Coefficients. Of particular importance are the DR rate coefficients for the iron L-shell ions (Fe XVII-Fe XXIV). These ions are predicted to play an important role in determining the thermal structure and line emission of X-ray photoionized plasmas, which form in the media surrounding accretion powered sources such as X-ray binaries (XRBs), active galactic nuclei (AGN), and cataclysmic variables (Savin et al., 2000). The need for reliable DR data of iron L-shell ions has become particularly urgent after the launches of Chandra and XMM-Newton. These satellites are now providing high-resolution X-ray spectra from a wide range of X-ray photoionized sources. Interpreting the spectra from these sources requires reliable DR rate coefficients. However, at the temperatures relevant, for X-ray photoionized plasmas, existing theoretical DR rate coefficients can differ from one another by factors of two to orders of magnitudes.

  12. Cosmic ray isotope measurements with a new Cerenkov X total energy telescope

    NASA Technical Reports Server (NTRS)

    Webber, W. R.; Kish, J. C.; Schrier, D. A.

    1985-01-01

    Measurements of the isotopic composition of cosmic nuclei with Z = 7-20 are reported. These measurements were made with a new version of a Cerenkov x total E telescope. Path length and uniformity corrections are made to all counters to a RMS level 1%. Since the Cerenkov counter is crucial to mass measurements using the C x E technique - special care was taken to optimize the resolution of the 2.4 cm thick Pilot 425 Cerenkov counter. This counter exhibited a beta = 1 muon equivalent LED resolution of 24%, corresponding to a total of 90 p.e. collected at the 1st dynodes of the photomultiplier tubes.

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

    ERIC Educational Resources Information Center

    Friedlander, Michael

    1990-01-01

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

  14. Cosmic X-ray Physics: Sounding rocket investigations of the diffuse X-ray background, including instrument development

    NASA Astrophysics Data System (ADS)

    McCammon, Dan

    We propose an investigation to improve our understanding of the Galactic diffuse X-ray background. The ultimate purpose of this is to determine the role of hot phases of the interstellar medium in mediating stellar feedback in star formation, in transport of metals, and in determining the structure and evolution of the Galaxy. It directly addresses SMD's astrophysics goal No. 2, to explore the origin and evolution of the galaxies, stars and planets that make up our universe. This work will involve a flight of an existing payload with small modifications in Woomera, South Australia, to observe the Galactic soft X-ray bulge and attempt to determine its nature and emission mechanisms. This flight should also either confirm or put strict upper limits on the "sterile neutrino" model for the 3.5 keV signal observed near the Galactic Center by XMM-Newton. Our investigation includes the development of thermal detectors with superconducting transition edge thermometers capable of 1-2 eV FWHM energy resolution in the 100-400 eV range with the intent of obtaining a scientifically useful spectrum on a sounding rocket flight of the emission from one million degree gas in this energy range. This will require a total area of 1-2 square centimeters for the detector array. To enable routine testing of such detectors in the lab and for necessary in-flight gain and resolution monitoring, we are trying to develop a pulsed-UV laser calibration source. In collaboration with Goddard Space Flight Center, we are investigating the practicality of waveguide-below-cutoff filters to provide the necessary attenuation of infrared radiation for these detectors while still allowing good x-ray transmission below 150 eV. The detectors, calibration source, filters, optimal high-rate pulse analysis and flight experience with the detector readouts are all relevant to future NASA major missions. The detectors we're working on for a low-energy sounding rocket flight would be an excellent match to what is

  15. Satellite Observations of Rapidly Varying Cosmic X-ray Sources. Ph.D. Thesis - Catholic Univ.

    NASA Technical Reports Server (NTRS)

    Maurer, G. S.

    1979-01-01

    The X-ray source data obtained with the high energy celestial X-ray detector on the Orbiting Solar Observatory -8 are presented. The results from the 1977 Crab observation show nonstatistical fluctuations in the pulsed emission and in the structure of the integrated pulse profile which cannot be attributed to any known systematic effect. The Hercules observations presented here provide information on three different aspects of the pulsed X-ray emission: the variation of pulsed flux as a function of the time from the beginning of the ON-state, the variation of pulsed flux as a function of binary phase, and the energy spectrum of the pulse emission.

  16. Cylindrical Crystal Imaging Spectrometer (CCIS) for cosmic X-ray spectroscopy

    NASA Technical Reports Server (NTRS)

    Schnopper, H. W.; Taylor, P. O.

    1981-01-01

    A "stigmatic" focusing, Bragg crystal spectrometer was developed and used for high spectral resolution X-ray emission line diagnostics on hot laboratory plasmas. The concept be applied at the focal plane of an orbiting X-ray telescope where it offers several advantages over conventional spectrometers, i.e., mechanical simplicity, high resolving power and sensitivity, simultaneous measurement of an extended segment of spectrum, and good imaging properties. The instrument features a simple, unambiguous, non-scanning spectrum readout that is not adversely affected by either spacecraft pointing error or source extent. The performance of the instrument is estimated in the context of the Advanced X-Ray Astrophysical Facility mission.

  17. Cosmic ray driven Galactic winds

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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 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 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.

  18. Antiprotons in cosmic rays

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  19. Can the cosmic x ray and gamma ray background be due to reflection of a steep power law spectrum and Compton scattering by relativistic electrons?

    NASA Technical Reports Server (NTRS)

    Zycki, Piotr T.; Zdziarski, Andrzej A.; Svensson, Roland

    1991-01-01

    We reconsider the recent model for the origin in the cosmic X-ray and gamma-ray background by Rogers and Field. The background in the model is due to an unresolved population of AGNs. An individual AGN spectrum contains three components: a power law with the energy index of alpha = 1.1, an enhanced reflection component, and a component from Compton scattering by relativistic electrons with a low energy cutoff at some minimum Lorentz factor, gamma(sub min) much greater than 1. The MeV bump seen in the gamma-ray background is then explained by inverse Compton emission by the electrons. We show that the model does not reproduce the shape of the observed X-ray and gamma-ray background below 10 MeV and that it overproduces the background at larger energies. Furthermore, we find the assumptions made for the Compton component to be physically inconsistent. Relaxing the inconsistent assumptions leads to model spectra even more different from that of the observed cosmic background. Thus, we can reject the hypothesis that the high-energy cosmic background is due to the described model.

  20. Radiation exposure due to cosmic rays and solar X-ray photons at various atmospheric heights in aviation range over India

    NASA Astrophysics Data System (ADS)

    Palit, Sourav; Chakrabarti, Sandip Kumar; Bhattacharya, Arnab

    2016-07-01

    In this presentation we present our work on the continuous monitoring of radiation exposure in terms of effective dose rates, due to galactic cosmic rays (GCR) and solar X-rays at various altitudes within aviation range over India. As India belongs to equatorial region, there is negligible contribution from solar energetic particles (SEP). The calculation of cosmic ray counts as well as the solar X-ray photons are performed on the basis of the observation of various Dignity series balloon experiments on cosmic ray and solar high energy radiation studies, conducted by ICSP and Monte Carlo simulations performed with GEANT4 detector simulation software. The information on solar activity level from Geostationary Operational Environmental Satellite system (GOES) are employed in the calculations. A program, which is done entirely in MATLAB is employed to update regularly in a website, where we show images of dose rate (μSv) distribution over India at four different heights within the aviation range (updating at an interval of 30 minutes) and the approximate dose rates thats should be experienced by a pilot in an entire flight time between pairs of stations distributed all over India.

  1. The Origin of Cosmic Rays

    ScienceCinema

    Blasi, Pasquale [INAF/Arcetri-Italy and Fermilab, Italy

    2010-01-08

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

  2. Continuous observations of long-term variations in cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Wende, C. D.; Krimigis, S. M.; Kohl, J. W.

    1975-01-01

    Results are reported for the Charged Particle Measurements Experiment which was conducted on board IMP-7 to detect X-ray fluxes from the sun, the galactic center, Tau X-1, and Sco X-1 over a nine-month period. Autocorrelation analysis of the data indicates a probable 80-day periodicity in the flux from Sco X-1, a 110-day periodicity in the flux from the galactic center, no periodicities in the flux from Tau X-1, and a strong 27-day periodicity in the solar X-ray flux. A transient event detected within the cluster of sources constituting the galactic center is reported which lasted about two months and had a flux roughly equal to the regular flux from this area. It is noted that this was the only transient event detected in the whole area under continuous observation for the duration of the experiment.

  3. WIDE ANGLE X-RAY SKY MONITORING FOR CORROBORATING NON-ELECTROMAGNETIC COSMIC TRANSIENTS

    SciTech Connect

    Guetta, Dafne; Eichler, David E-mail: eichler@bgumail.bgu.ac.i

    2010-03-20

    Gravitational waves (GWs) can be emitted from coalescing neutron star (NS) and black hole-neutron star binaries, which are thought to be the sources of short hard gamma-ray bursts (SHBs). The gamma-ray fireballs seem to be beamed into a small solid angle and therefore only a fraction of detectable GW events are expected to be observationally coincident with SHBs. Similarly, ultrahigh energy neutrino signals associated with gamma-ray bursts could fail to be corroborated by prompt gamma-ray emission if the latter is beamed into a narrower cone than the neutrinos. Alternative ways to corroborate non-electromagnetic signals from coalescing NSs are therefore all the more desirable. It is noted here that the extended X-ray tails (XRTs) of SHBs are similar to X-ray flashes (XRFs), and that both can be attributed to an off-axis line of sight and thus span a larger solid angle than the hard emission. It is proposed that a higher fraction of detectable GW events may be coincident with XRF/XRT than with hard gamma-rays, thereby enhancing the possibility of detecting it as a GW or neutrino source. Scattered gamma-rays, which may subtend a much larger solid angle than the primary gamma-ray jet, are also candidates for corroborating non-electromagnetic signals.

  4. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, Stephen S.

    1987-01-01

    The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

  5. Cosmic-Rays and Gamma Ray Bursts

    NASA Astrophysics Data System (ADS)

    Meli, A.

    2013-07-01

    Cosmic-rays are subatomic particles of energies ranging between a few eV to hundreds of TeV. These particles register a power-law spectrum, and it seems that most of them originate from astrophysical galactic and extragalactic sources. The shock acceleration in superalfvenic astrophysical plasmas, is believed to be the main mechanism responsible for the production of the non-thermal cosmic-rays. Especially, the importance of the very high energy cosmic-ray acceleration, with its consequent gamma-ray radiation and neutrino production in the shocks of the relativistic jets of Gamma Ray Bursts, is a favourable theme of study. I will discuss the cosmic-ray shock acceleration mechanism particularly focusing on simulation studies of cosmic-ray acceleration occurring in the relativistic shocks of GRB jets.

  6. Superbubbles and Local Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Streitmatter, Robert E.; Jones, Frank C.

    2005-01-01

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

  7. Cosmic Rays and Experiment CZELTA

    SciTech Connect

    Smolek, Karel; Nyklicek, Michal

    2007-11-26

    This paper gives a review of the physics of cosmic rays with emphasis on the methods of detection and study. A summary is given of the Czech project CZELTA which is part of a multinational program to study cosmic rays with energies above 10{sup 14} eV.

  8. Testing Galactic Cosmic Ray Models

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.

    2010-01-01

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

  9. Testing Galactic Cosmic Ray Models

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.

    2009-01-01

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

  10. Large area focusing collector for the observation of cosmic X rays.

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Decaprio, A.; Chase, R.; Harris, B.

    1973-01-01

    A large area focusing X-ray collector constructed for a sounding rocket is described. The instrument consists of nested reflecting plates that are curved slightly in one dimension to form a set of parabolas with a common focus. An array of plates such as the one in the sounding rocket focuses a parallel beam of X-rays to a line. The reflecting surfaces are commercial float glass with an evaporated metallic coating such as gold or nickel. With a gold coating, the effective area of the rocket collector is about 250 sq cm for 0.3 keV X rays and about 150 sq cm at 1.2 keV. Its angular resolution is a few arc minutes and field of view is about plus or minus .75 deg (full width at half maximum). The collector performed successfully during a sounding rocket flight.

  11. Ion Storage Ring Measurements of Low Temperature Dielectronic Recombination Rate Coefficients for Modeling X-Ray Photoionized Cosmic Plasmas

    NASA Astrophysics Data System (ADS)

    Savin, D. W.; Gwinner, G.; Schwalm, D.; Wolf, A.; Müller, A.; Schippers, S.

    2002-11-01

    Low temperature dielectronic recombination (DR) is the dominant recombination mechanism for most ions in X-ray photoionized cosmic plasmas. Reliably modeling and interpreting spectra from these plasmas requires accurate low temperature DR rate coefficients. Of particular importance are the DR rate coefficients for the iron L-shell ions (Fe XVII -Fe XXIV). These ions are predicted to play an important role in determining the thermal structure and line emission of X-ray photoionized plasmas, which form in the media surrounding accretion powered sources such as X-ray binaries (XRBs), active galactic nuclei (AGN), and cataclysmic variables (Savin et al. 2000). The need for reliable DR data of iron L-shell ions has become particularly urgent after the launches of Chandra and XMM-Newton. These satellites are now providing high-resolution X-ray spectra from a wide range of X-ray photoionized sources. Interpreting the spectra from these sources requires reliable DR rate coefficients. However, at the temperatures relevant for X-ray photoionized plasmas, existing theoretical DR rate coefficients can differ from one another by factors of two to orders of magnitudes. To address the need for accurate low temperature DR rate coefficients of the iron L-shell ions, we have initiated a program of measurements for DR via 2 to 2 core excitations using the heavy-ion Test Storage Ring located at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany. To date measurements have been carried out for Fe XVIII (Savin et al. 1997, 1999), Fe XIX (Savin et al. 1999), Fe XX (Savin et al. 2002), Fe XXI, Fe XXII, and Fe XXIV. Here we review our work to date, discuss the implications of our results, and map out our future research efforts. This work was supported in part by NASA SARA Program grant NAG5-5261, the German Federal Minister for Education and Research (BMBF), and the German Research Council (DFG).

  12. The history of cosmic baryons: X-ray emission versus star formation rate

    NASA Astrophysics Data System (ADS)

    Menci, N.; Cavaliere, A.

    2000-01-01

    We relate the star formation from cold baryons condensing in virialized structures to the X-ray properties of the associated diffuse, hot baryonic component. Our computations use the standard `semi-analytic' models to include and connect three sectors of the complex astrophysics involved: first, the formation of dark matter haloes through accretion and merging, after the standard hierarchical clustering; secondly, the star formation governed, after the current `recipes', by radiative cooling and by feedback of the supernova energy into the hot baryonic component; thirdly, and novel, the hydrodynamics and thermodynamics of the hot phase, rendered with our Punctuated Equilibria model. So we relate the X-ray observables concerning the intracluster medium (namely, the luminosity-temperature relation, the luminosity functions, the source counts) to the thermal energy of the gas pre-heated and expelled by supernovae following star formation, and then accreted during the subsequent merging events. Our main results are as follows. At fluxes fainter than FX~10-15ergcm-2s-1 the X-ray counts of extended extragalactic sources (as well as the faint end of the luminosity function, their contribution to the soft X-ray background, and the LX-T correlation at the group scales) increase considerably if the star formation rate is high for z>1 as indicated by growing optical/infrared evidence. Specifically, the counts in the range 0.5-2keV are increased by factors ~4 when the the feedback is decreased and the star formation is enhanced as to yield a flat shape of the star formation rate for 2X-ray observatories like AXAF and XMM. So very faint X-ray counts will soon constitute a new means of gaining information about the stellar processes (formation, and supernova feedback) at z>2, and a new way to advance the understanding of the galaxy formation.

  13. Nighttime sensitivity of ionospheric VLF measurements to X-ray bursts from a remote cosmic source

    NASA Astrophysics Data System (ADS)

    Raulin, Jean-Pierre; Trottet, Gérard; Giménez de Castro, C. Guillermo; Correia, Emilia; Macotela, E. Liliana

    2014-06-01

    On 22 January 2009, a series of X-ray bursts were emitted by the soft gamma ray repeater SGR J1550-5418. Some of these bursts produced enhanced ionization in the nighttime lower ionosphere. These ionospheric disturbances were studied using X-ray measurements from the Anti-Coincidence Shield of the Spectrometer for Integral onboard the International Gamma-Ray Astrophysics Laboratory and simultaneous phase and amplitude records from two VLF propagation paths between the transmitter Naval Radio Station, Pearl Harbor (Hawaii) and the receivers Radio Observatorio do Itapetinga (Brazil) and Estação Antarctica Commandante Ferraz (Antarctic Peninsula). The VLF measurements have been obtained with an unprecedented high time resolution of 20 ms. We find that the illumination factor I (illuminated path length times the cosine of the zenith angle), which characterizes the propagation paths underlying the flaring object, is a key parameter which determines the sensitivity threshold of the VLF detection of X-ray bursts from nonsolar transients. For the present VLF measurements of bursts from SGR J1550-5418, it is found that for I ≥ 1.8 Mm, all X-ray bursts with fluence in the 25 keV to 2 MeV range larger than F25_min ~ 1.0 × 10-6 erg/cm2 produce a measurable ionospheric disturbance. Such a lower limit of the X-ray fluence value indicates that moderate X-ray bursts, as opposed to giant X-ray bursts, do produce ionospheric disturbances larger than the sensitivity limit of the VLF technique. Therefore, the frequency of detection of such events could be improved, for example by increasing the coverage of existing VLF receiving networks. The VLF detection of high-energy astrophysical bursts then appears as an important observational diagnostic to complement their detection in space. This would be especially important when space observations suffer from adverse conditions, like saturation, occultation from the Earth, or the passage of the spacecraft through the South Atlantic

  14. Genesis and propagation of cosmic rays

    SciTech Connect

    Shapiro, M.M.; Wefel, J.P.

    1988-01-01

    This book presents a panorama of contemporary state-of-the-art knowledge on the origin of cosmic rays and how they propagate through space. Twenty-eight articles cover such topics as objects which generate cosmic rays, processes which accelerate particles to cosmic ray energies, the interaction of cosmic rays with their environment, elementary particles in cosmic rays, how to detect cosmic rays and future experiments to measure highly energetic particles.

  15. Observation of the suppression of the flux of cosmic rays above 4x10^19eV

    SciTech Connect

    Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.; /Wisconsin U., Milwaukee /Northeastern U. /Lisbon, IST /Lisbon, LIFEP

    2008-06-01

    The energy spectrum of cosmic rays above 2.5 x 10{sup 18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index {gamma} of the particle flux, J {proportional_to} E{sup {gamma}}, at energies between 4 x 10{sup 18} eV and 4 x 10{sup 19} eV is 2.69 {+-} 0.02(stat){+-}0.06(syst), steepening to 4.2 {+-} 0.4(stat){+-}0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuzmin.

  16. Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV.

    PubMed

    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; Baughman, B; 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; Bohácová, 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; Chudoba, J; Chye, J; Clark, P D 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; Junior, W J M de Mello; Neto, J R T de Mello; De Mitri, I; de Souza, V; Del Peral, L; Deligny, O; Della Selva, A; Fratte, C Delle; 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; Luis, P Facal San; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Ferrer, F; Ferrero, A; Fick, B; Filevich, A; Filipcic, A; Fleck, I; Fracchiolla, C E; Fulgione, W; García, B; Gámez, D García; Garcia-Pinto, D; Garrido, X; Geenen, H; Gelmini, G; Gemmeke, H; Ghia, P L; Giller, M; Glass, H; Gold, M S; Golup, G; Albarracin, F Gomez; Berisso, M Gómez; Gonçalves, P; do Amaral, M Gonçalves; 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; Halenka, V; 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 R; Horneffer, A; Hrabovský, M; Huege, T; Hussain, M; Iarlori, M; Insolia, A; Ionita, F; Italiano, A; Kaducak, M; Kampert, K H; Karova, T; Kasper, P; 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; Agüera, A Lopez; Bahilo, J Lozano; Lucero, A; 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; Bravo, O Martínez; 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; Melo, D; Menichetti, E; Menschikov, A; Meurer, C; 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; Nozka, 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; Pekala, J; Pelayo, R; Pepe, I M; Perrone, L; Pesce, R; 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; Martino, J Rodriguez; Rojo, J Rodriguez; 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; Schroeder, F; Schulte, S; Schüssler, F; Sciutto, S J; Scuderi, M; Segreto, A; Semikoz, D; Settimo, M; Shellard, R C; Sidelnik, I; Siffert, B B; Sigl, G

    2008-08-01

    The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. PMID:18764444

  17. Gamma rays, cosmic rays, and galactic structure

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1977-01-01

    Observations of cosmic and gamma radiation by SAS-2 satellite are summarized and analyzed to determine processes responsible for producing observed galactic radiation. In addition to the production of gamma rays in discrete galactic objects such as pulsars, there are three main mechanisms by which high-energy (greater than 100 MeV) radiation is produced by high-energy interactions involving cosmic rays in interstellar space. These processes, which produce what may be called diffuse galactic gamma-rays, are: (1) the decay of pi mesons produced by interactions of cosmic ray nucleons with interstellar gas nuclei; (2) the bremsstrahlung radiation produced by cosmic ray electrons interacting in the Coulomb fields of nuclei of interstellar gas atoms; and (3) Compton interactions between cosmic ray electrons and low-energy photons in interstellar space.

  18. The distribution of cosmic rays in the galaxy and their dynamics as deduced from recent gamma-ray observations. [X-ray intensity variations with galactocentric distance

    NASA Technical Reports Server (NTRS)

    Puget, J. L.; Stecker, F. W.

    1974-01-01

    Recent data from SAS-2 on the galactic gamma ray line flux as a function of longitude reveal a broad maximum in the gamma ray intensity in the region absolute value of l approximately smaller than 30 deg. These data imply that the low energy galactic cosmic ray flux varies with galactocentric distance and is about an order of magnitude higher than the local value in a toroidal region between 4 and 5 kpc from the galactic center. This enhancement can be plausibly accounted for by first order Fermi acceleration, compression and trapping of cosmic rays consistent with present ideas of galactic dynamics and galactic structure theory. Calculations indicate that cosmic rays in the 4 to 5 kpc region are trapped and accelerated over a mean time of the order of a few million years or about 2 to 4 times the assumed trapping time in the solar region of the galaxy.

  19. Solar Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, Leonty I.

    2001-05-01

    The book summarizes the results of solar cosmic-ray (SCR) investigations since 1942. The present monograph, unlike the reviews published earlier, treats the problem in self-contained form, in all its associations - from fundamental astrophysical aspects to geophysical and astronautical applications. It includes a large amount of new data, accumulated during the last two or three decades of space research. As a result of the `information burst' in space physics, there are a lot of new interesting theoretical concepts, models, and ideas that deserve attention. The author gives an extensive bibliography which covers incompartially the main achievements and failures in this field. The book will be helpful for a wide audience of space physicists and it will be relevant to graduate and postgraduate courses.

  20. Cosmic Ray Scattering Radiography

    NASA Astrophysics Data System (ADS)

    Morris, C. L.

    2015-12-01

    Cosmic ray muons are ubiquitous, are highly penetrating, and can be used to measure material densities by either measuring the stopping rate or by measuring the scattering of transmitted muons. The Los Alamos team has studied scattering radiography for a number of applications. Some results will be shown of scattering imaging for a range of practical applications, and estimates will be made of the utility of scattering radiography for nondestructive assessments of large structures and for geological surveying. Results of imaging the core of the Toshiba Nuclear Critical Assembly (NCA) Reactor in Kawasaki, Japan and simulations of imaging the damaged cores of the Fukushima nuclear reactors will be presented. Below is an image made using muons of a core configuration for the NCA reactor.

  1. X-Ray Synchrotron Emission From 10-100 TeV Cosmic-Ray Electrons In The Supernova Remnant SN 1006

    NASA Technical Reports Server (NTRS)

    Allen, G. E.; Petre, R.; Gotthelf, E. V.

    2001-01-01

    We present the results of a joint spectral analysis of RXTE PCA, ASCA SIS, and ROSAT PSPC data of the supernova remnant SN 1006. This work represents the first attempt to model both the thermal and nonthermal X-ray emission over the entire X-ray energy band from 0.12 to 17 key. The thermal flux is described by a nonequilibrium ionization model with an electron temperature kTe = 0.6 key, an ionization timescale n(sub 0)t = 9 x 10(exp 9)/cc s, and a relative elemental abundance of silicon that is 10 - 18 times larger than the solar abundance. The nonthermal X-ray spectrum is described by a broken power law model with low- and high-energy photon indices Gamma(sub 1) = 2.1 and Gamma(sub 2) = 3.0, respectively. Since the nonthermal X-ray spectrum steepens with increasing energy, the results of the present analysis corroborate previous claims that the nonthermal X-ray emission is produced by synchrotron radiation. We argue that the magnetic field strength is significantly larger than previous estimates of about 10 micro G and arbitrarily use a value of 40 micro G to estimate the parameters of the cosmic-ray electron, proton, and helium spectra of the remnant. The results for the ratio of the number densities of protons and electrons (R = 160 at 1 GeV), the total energy in cosmic rays (E(sub cr) = 1 x 10(exp 50) ergs), and the spectral index of the electrons at 1 GeV (Gamma(sub e) = 2.14 +/- 0.12) are consistent with the hypothesis that Galactic cosmic rays are accelerated predominantly in the shocks of supernova remnants. Yet, the remnant may or may not accelerate nuclei to energies as high as the energy of the "knee," depending on the reason why the maximum energy of the electrons is only 10 TeV.

  2. A selection effect boosting the contribution from rapidly spinning black holes to the cosmic X-ray background

    NASA Astrophysics Data System (ADS)

    Vasudevan, R. V.; Fabian, A. C.; Reynolds, C. S.; Aird, J.; Dauser, T.; Gallo, L. C.

    2016-05-01

    The cosmic X-ray background (CXB) is the total emission from past accretion activity on to supermassive black holes in active galactic nuclei (AGN) and peaks in the hard X-ray band (30 keV). In this paper, we identify a significant selection effect operating on the CXB and flux-limited AGN surveys, and outline how they must depend heavily on the spin distribution of black holes. We show that, due to the higher radiative efficiency of rapidly spinning black holes, they will be over-represented in the X-ray background, and therefore could be a dominant contributor to the CXB. Using a simple bimodal spin distribution, we demonstrate that only 15 per cent maximally spinning AGN can produce 50 per cent of the CXB. We also illustrate that invoking a small population of maximally spinning black holes in CXB synthesis models can reproduce the CXB peak without requiring large numbers of Compton-thick AGN. The spin bias is even more pronounced for flux-limited surveys: 7 per cent of sources with maximally spinning black holes can produce half of the source counts. The detectability for maximum spin black holes can be further boosted in hard (>10 keV) X-rays by up to ˜60 per cent due to pronounced ionized reflection, reducing the percentage of maximally spinning black holes required to produce half of the CXB or survey number counts further. A host of observations are consistent with an over-representation of high-spin black holes. Future NuSTAR and ASTRO-H hard X-ray surveys will provide the best constraints on the role of spin within the AGN population.

  3. Infrared-faint radio sources: a cosmological view. AGN number counts, the cosmic X-ray background and SMBH formation

    NASA Astrophysics Data System (ADS)

    Zinn, P.-C.; Middelberg, E.; Ibar, E.

    2011-07-01

    Context. Infrared-faint radio sources (IFRS) are extragalactic emitters clearly detected at radio wavelengths but barely detected or undetected at optical and infrared wavelengths, with 5σ sensitivities as low as 1 μJy. Aims: Spectral energy distribution (hereafter SED) modelling and analyses of their radio properties indicate that IFRS are consistent with a population of (potentially extremely obscured) high-redshift AGN at 3 ≤ z ≤ 6. We demonstrate some astrophysical implications of this population and compare them to predictions from models of galaxy evolution and structure formation. Methods: We compiled a list of IFRS from four deep extragalactic surveys and extrapolated the IFRS number density to a survey-independent value of (30.8 ± 15.0) deg-2. We computed the IFRS contribution to the total number of AGN in the Universe to account for the cosmic X-ray background. By estimating the black hole mass contained in IFRS, we present conclusions for the SMBH mass density in the early universe and compare it to relevant simulations of structure formation after the Big Bang. Results: The number density of AGN derived from the IFRS density was found to be ~310 deg-2, which is equivalent to a SMBH mass density of the order of 103 M⊙ Mpc-3 in the redshift range 3 ≤ z ≤ 6. This produces an X-ray flux of 9 × 10-16 W m-2 deg-2 in the 0.5-2.0 keV band and 3 × 10-15 W m-2 deg-2 in the 2.0-10 keV band, in agreement with the missing unresolved components of the Cosmic X-ray Background. To address SMBH formation after the Big Bang we invoke a scenario involving both halo gas accretion and major mergers.

  4. Cosmic rays in the heliosphere

    NASA Technical Reports Server (NTRS)

    Webber, William R.

    1987-01-01

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

  5. Radiative Transfer in a Clumpy Universe. IV. New Synthesis Models of the Cosmic UV/X-Ray Background

    NASA Astrophysics Data System (ADS)

    Haardt, Francesco; Madau, Piero

    2012-02-01

    We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. Five new main components are added to our radiative transfer code CUBA: (1) the sawtooth modulation of the background intensity from resonant line absorption in the Lyman series of cosmic hydrogen and helium; (2) the X-ray emission from the obscured and unobscured quasars that gives origin to the X-ray background; (3) a piecewise parameterization of the distribution in redshift and column density of intergalactic absorbers that fits recent measurements of the mean free path of 1 ryd photons; (4) an accurate treatment of the photoionization structure of absorbers, which enters in the calculation of the helium continuum opacity and recombination emissivity; and (5) the UV emission from star-forming galaxies at all redshifts. We provide tables of the predicted H I and He II photoionization and photoheating rates for use, e.g., in cosmological hydrodynamics simulations of the Lyα forest and a new metallicity-dependent calibration to the UV luminosity density-star formation rate density relation. A "minimal cosmic reionization model" is also presented in which the galaxy UV emissivity traces recent determinations of the cosmic history of star formation, the luminosity-weighted escape fraction of hydrogen-ionizing radiation increases rapidly with look-back time, the clumping factor of the high-redshift intergalactic medium evolves following the results of hydrodynamic simulations, and Population III stars and miniquasars make a negligible contribution to the metagalactic flux. The model provides a good fit to the hydrogen-ionization rates inferred from flux decrement and proximity effect measurements, predicts that cosmological H II (He III) regions overlap at redshift 6.7 (2.8), and yields an optical depth to Thomson scattering, τes = 0.084 that is in agreement with Wilkinson Microwave Anisotropy Probe results. Our new

  6. RADIATIVE TRANSFER IN A CLUMPY UNIVERSE. IV. NEW SYNTHESIS MODELS OF THE COSMIC UV/X-RAY BACKGROUND

    SciTech Connect

    Haardt, Francesco; Madau, Piero E-mail: pmadau@ucolick.org

    2012-02-20

    We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. Five new main components are added to our radiative transfer code CUBA: (1) the sawtooth modulation of the background intensity from resonant line absorption in the Lyman series of cosmic hydrogen and helium; (2) the X-ray emission from the obscured and unobscured quasars that gives origin to the X-ray background; (3) a piecewise parameterization of the distribution in redshift and column density of intergalactic absorbers that fits recent measurements of the mean free path of 1 ryd photons; (4) an accurate treatment of the photoionization structure of absorbers, which enters in the calculation of the helium continuum opacity and recombination emissivity; and (5) the UV emission from star-forming galaxies at all redshifts. We provide tables of the predicted H I and He II photoionization and photoheating rates for use, e.g., in cosmological hydrodynamics simulations of the Ly{alpha} forest and a new metallicity-dependent calibration to the UV luminosity density-star formation rate density relation. A 'minimal cosmic reionization model' is also presented in which the galaxy UV emissivity traces recent determinations of the cosmic history of star formation, the luminosity-weighted escape fraction of hydrogen-ionizing radiation increases rapidly with look-back time, the clumping factor of the high-redshift intergalactic medium evolves following the results of hydrodynamic simulations, and Population III stars and miniquasars make a negligible contribution to the metagalactic flux. The model provides a good fit to the hydrogen-ionization rates inferred from flux decrement and proximity effect measurements, predicts that cosmological H II (He III) regions overlap at redshift 6.7 (2.8), and yields an optical depth to Thomson scattering, {tau}{sub es} = 0.084 that is in agreement with Wilkinson Microwave Anisotropy Probe results

  7. Supernova Remnants, Cosmic Rays, and GLAST

    SciTech Connect

    Reynolds, Steve

    2006-02-13

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

  8. Supernova Remnants, Cosmic Rays, and GLAST

    SciTech Connect

    Reynolds, Steve

    2006-02-13

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

  9. Spatial Fluctuations in the Diffuse Cosmic X-Ray Background. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Shafer, R. A.

    1983-01-01

    The bright, essentially isotropic, X-ray sky flux above 2 keV yields information on the universe at large distances. However, a definitive understanding of the origin of the flux is lacking. Some fraction of the total flux is contributed by active galactic nuclei and clusters of galaxies, but less than one percent of the total is contributed by the or approximately 3 keV band resolved sources, which is the band where the sky flux is directly observed. Parametric models of AGN (quasar) luminosity function evolution are examined. Most constraints are by the total sky flux. The acceptability of particular models hinges on assumptions currently not directly testable. The comparison with the Einstein Observatory 1 to keV low flux source counts is hampered by spectral uncertainties. A tentative measurement of a large scale dipole anisotropy is consistent with the velocity and direction derived from the dipole in the microwave background. The impact of the X-ray anisotropy limits for other scales on studies of large-scale structure in the universe is sketched. Models of the origins of the X-ray sky flux are reviewed, and future observational programs outlined.

  10. Spaced-based Cosmic Ray Astrophysics

    NASA Astrophysics Data System (ADS)

    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.

  11. Numerical Cosmic-Ray Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Miniati, F.

    2009-04-01

    We present a numerical method for integrating the equations describing a system made of a fluid and cosmic-rays. We work out the modified characteristic equations that include the CR dynamical effects in smooth flows. We model the energy exchange between cosmic-rays and the fluid, due to diffusive processes in configuration and momentum space, with a flux conserving method. For a specified shock acceleration efficiency as a function of the upstream conditions and shock Mach number, we modify the Riemann solver to take into account the cosmic-ray mediation at shocks without resolving the cosmic-ray induced substructure. A self-consistent time-dependent shock solution is obtained by using our modified solver with Glimm's method. Godunov's method is applied in smooth parts of the flow.

  12. Cosmic rays, clouds, and climate.

    PubMed

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

    2002-11-29

    It has been proposed that Earth's climate could be affected by changes in cloudiness caused by variations in the intensity of galactic cosmic rays in the atmosphere. This proposal stems from an observed correlation between cosmic ray intensity and Earth's average cloud cover over the course of one solar cycle. Some scientists question the reliability of the observations, whereas others, who accept them as reliable, suggest that the correlation may be caused by other physical phenomena with decadal periods or by a response to volcanic activity or El Niño. Nevertheless, the observation has raised the intriguing possibility that a cosmic ray-cloud interaction may help explain how a relatively small change in solar output can produce much larger changes in Earth's climate. Physical mechanisms have been proposed to explain how cosmic rays could affect clouds, but they need to be investigated further if the observation is to become more than just another correlation among geophysical variables. PMID:12459578

  13. Cosmic ray biannual variation

    NASA Technical Reports Server (NTRS)

    Attolini, M. R.; Cecchini, S.; Cinicastagnoli, G.; Galli, M.

    1985-01-01

    The study of the cosmic ray (CR) power spectrum has revealed a significant variation with a period around 2 yr that cannot be explained as a high order harmonic of the 11 yr solar cycle. Comparative study of the correlation on different time scales between CR intensity and Rz, aa, high speed streams and polar hole size has put in evidence that a high degree of coherency exists between each couple of variables at 1.58 to 1.64 yr, except between CR and Rz. On the other hand cyclic variation on a short time scale, around 26 months, has been claimed to be present in the neutrino flux. Critical tests of this hypothesis are considered and a preliminary result seems to indicate that the hypothesis of the existence of a 1.6 yr periodicity in the neutrino data during the measurement time interval, has a significance or = 99.9%. The possible origin of this variation as due to a contribution either of CR interactions in the upper atmosphere or to the solar dynamics, are discussed.

  14. Protostars: Forges of cosmic rays?

    NASA Astrophysics Data System (ADS)

    Padovani, M.; Marcowith, A.; Hennebelle, P.; Ferrière, K.

    2016-05-01

    Context. Galactic cosmic rays are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy and their ionisation efficiency because of the presence of magnetic fields and collisions with molecular hydrogen. Recent observations hint at high levels of ionisation and at the presence of synchrotron emission in protostellar systems, which leads to an apparent contradiction. Aims: We want to explain the origin of these cosmic rays accelerated within young protostars as suggested by observations. Methods: Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient cosmic-ray acceleration through diffusive shock acceleration. We analyse three main acceleration sites (shocks in accretion flows, along the jets, and on protostellar surfaces), then we follow the propagation of these particles through the protostellar system up to the hot spot region. Results: We find that jet shocks can be strong accelerators of cosmic-ray protons, which can be boosted up to relativistic energies. Other promising acceleration sites are protostellar surfaces, where shocks caused by impacting material during the collapse phase are strong enough to accelerate cosmic-ray protons. In contrast, accretion flow shocks are too weak to efficiently accelerate cosmic rays. Though cosmic-ray electrons are weakly accelerated, they can gain a strong boost to relativistic energies through re-acceleration in successive shocks. Conclusions: We suggest a mechanism able to accelerate both cosmic-ray protons and electrons through the diffusive shock acceleration mechanism, which can be used to explain the high ionisation rate and the synchrotron emission observed towards protostellar sources. The existence of an internal source of energetic particles can have a strong and unforeseen impact on the ionisation of the protostellar disc, on the star and planet formation

  15. High resolution hard X-ray spectra of solar and cosmic sources. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Schwartz, R. A.

    1984-01-01

    High resolution hard X-ray observations of a large solar flare and the Crab Nebula were obtained during balloon flights using an array of cooled germanium planar detectors. In addition, high time resolution high sensitivity measurements were obtained with a 300 square cm NaI/CsI phoswich scintillator. The Crab spectrum from both flights was searched without finding evidence of line emission below 200 keV. In particular, for the 73 keV line previously reported a 3 sigma upper limit for a narrow (1 keV FWHM) line .0019 and .0014 ph square cm/sec for the 1979 and 1980 flights, respectively was obtained.

  16. Synchrotron x-ray fluorescence analyses of stratospheric cosmic dust: New results for chondritic and nickel-depleted particles

    SciTech Connect

    Flynn, G.J.; Sutton, S.R.

    1989-06-01

    Trace element abundance determinations were performed using synchrotron x-ray fluorescence on nine particles collected from the stratosphere and classified as ''cosmic''. Improvements to the Synchrotron Light Source allowed the detection of all elements between Cr and Mo, with the exceptions of Co and As, in our largest particle. The minor and trace element abundance patterns of three Ni-depleted particles were remarkably similar to those of extraterrestrial igneous rocks. Fe/Ni and Fe/Mn ratios suggest that one of these may be of lunar origin. All nine particles exhibited an enrichment in Br, ranging form 1.3 to 38 times the Cl concentration. Br concentrations were uncorrelated with particle size, as would be expected for a surface correlated component acquires from the stratosphere. 27 refs., 4 figs., 2 tabs.

  17. A re-consideration of the HEAO-1 A2 Measurements of the Cosmic X-ray Background Surface Brightness

    NASA Astrophysics Data System (ADS)

    Jahoda, K.

    2005-12-01

    The HEAO-1 A2 experiment was designed to make high precision and low systematics measurements of the Cosmic X-ray Background from 0.1 - 60 keV. No subsequent experiment has been capable of similarly clean separation of cosmic and instrumental background. Most more recent measurements of the 2-10 keV surface brightness are 20% higher than values derived from the spectral parameterization of the 3-50 keV spectrum given in the original A2 analysis of Marshall et al. (1980, ApJ 235, 4 (M80)). A recent analysis of archival A2 data by Revnivtsev et al. (astro-ph/0412304 (R05)) finds a surface brightness 15-20% higher than M80, an uncomfortably large discrepancy for data taken from a single experiment. We present a third analysis of the A2 data and identify two effects neglected in the comparison of previous A2 results: (a) the extrapolation of the M80 parameterization below 3 keV fails to describe the data; (b) R05 uses an unabsorbed, and high, value for the flux from the Crab nebula plus pulsar which results in a high value for the inferred count rate to CXB surface brightness conversion. Correcting for these effects, our best estimate of the 2-10 keV surface brightness is 1.84 × 10-11 ergs cm-2 s-1 deg-2 on a flux scale where the (absorbed) 2-10 Crab flux is 2.32 × 10-8 ergs cm-2 s-1. This value is only about 10% below the average compiled by Moretti et al. (2003, ApJ, 588, 696). We discuss how well the X-ray brightness of the Crab, to which this measurement is normalized, is known. This research made use of data from the High Energy Astrophysics Science Archive Research Center (HEASARC), provided by NASA's Goddard Space Flight Center.

  18. Development of cosmic ray techniques

    NASA Technical Reports Server (NTRS)

    Rossi, B.

    1982-01-01

    It is pointed out that most advances of cosmic-ray physics have been directly related to the development of observational techniques. A review is presented of the history of the evolution of the techniques and equipment for the study of cosmic-ray physics, taking into account the new scientific advances accompanying each new development related to experimental technology. All of the early observations were performed by means of ionization chambers. These chambers had already been in use for a number of years, when they were first applied to the study of cosmic rays in the early years of this century. However, an application to the low-intensity cosmic radiation required special refinements. Attention is given to the design of suitable electrometers, the development of self-recording instruments, the 'tube counter', the development of the coincidence method, a cosmic-ray 'telescope', a magnetic lens for cosmic rays, an arrangement of Geiger-Mueller counters for the demonstration of secondary radiation, cloud chambers, scintillation counters, and air shower experiments.

  19. Cosmic ray albedo gamma rays from the quiet sun

    NASA Technical Reports Server (NTRS)

    Seckel, D.; Stanev, T.; Gaisser, T. K.

    1992-01-01

    We estimate the flux of gamma-rays that result from collisions of high energy galactic cosmic rays with the solar atmosphere. An important aspect of our model is the propagation of cosmic rays through the magnetic fields of the inner solar systems. We use diffusion to model propagation down to the bottom of the corona. Below the corona we trace particle orbits through the photospheric fields to determine the location of cosmic ray interactions in the solar atmosphere and evolve the resultant cascades. For our nominal choice of parameters, we predict an integrated flux of gamma rays (at 1 AU) of F(E(sub gamma) greater than 100 MeV) approximately = 5 x 10(exp -8)/sq cm sec. This can be an order of magnitude above the galactic background and should be observable by the Energetic Gamma Ray experiment telescope (EGRET).

  20. Studying Dark Energy, Black Holes and Cosmic Feedback at X-ray Wavelengths: NASA's Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    Hornschemeier, A.

    2005-01-01

    Among the most important topics in modern astrophysics are the nature of the dark energy equation of state, the formation and evolution of supermassive black holes in concert with galaxy bulges, and the self-regulating symmetry imposed by both stellar and AGN feedback. All of these topics are readily addressed with observations at X-ray wavelengths. For instance, theoretical models predict that the majority (98%) of the energy and metal content in starburst superwinds exists in the hot million-degree gas. The Constellation-X observatory is being developed to perform spatially resolved high-resolution X-ray spectroscopy so that we may directly measure the absolute element abundances and velocities of this hot gas. This talk focuses on the driving science behind this mission, which is one of two flagship missions in NASA's Beyond Einstein program. A general overview of the observatory's capabilities and basic technology will also be given.

  1. Euclidean slope of the X-ray source counts: a cosmic conspiracy

    SciTech Connect

    Gioia, I.M.; Maccacaro, T.

    1984-01-01

    The selection criteria adopted for the Einstein Observatory Medium Sensitivity survey are delineated and the results of an analysis of the source-count relation for extragalactic X ray sources is presented. Only IPC fields at least 20 deg outside of the galactic plane, and then only those images in the center of the fields, were included. A total of 345 objects were sighted in the 0.3-3.5 keV energy interval, and 77 percent were concluded to be extragalactic. Most were associated with active galactic nuclei (AGN), including Seyfert galaxies and quasars, and galactic clusters. A slope of about 1.7 was calculated for the power law of the energy spectra of AGNs and close to 1.0 for clusters. 10 references.

  2. The Euclidean slope of the X-ray source counts - A 'cosmic conspiracy'

    NASA Technical Reports Server (NTRS)

    Gioia, I. M.; Maccacaro, T.

    1984-01-01

    The selection criteria adopted for the Einstein Observatory Medium Sensitivity survey are delineated and the results of an analysis of the source-count relation for extragalactic X ray sources is presented. Only IPC fields at least 20 deg outside of the galactic plane, and then only those images in the center of the fields, were included. A total of 345 objects were sighted in the 0.3-3.5 keV energy interval, and 77 percent were concluded to be extragalactic. Most were associated with active galactic nuclei (AGN), including Seyfert galaxies and quasars, and galactic clusters. A slope of about 1.7 was calculated for the power law of the energy spectra of AGNs and close to 1.0 for clusters.

  3. Superdiffusion of cosmic rays: Implications for cosmic ray acceleration

    SciTech Connect

    Lazarian, A.; Yan, Huirong

    2014-03-20

    Diffusion of cosmic rays (CRs) is the key process for understanding their propagation and acceleration. We employ the description of spatial separation of magnetic field lines in magnetohydrodynamic turbulence in Lazarian and Vishniac to quantify the divergence of the magnetic field on scales less than the injection scale of turbulence and show that this divergence induces superdiffusion of CR in the direction perpendicular to the mean magnetic field. The perpendicular displacement squared increases, not as the distance x along the magnetic field, which is the case for a regular diffusion, but as the x {sup 3} for freely streaming CRs. The dependence changes to x {sup 3/2} for the CRs propagating diffusively along the magnetic field. In the latter case, we show that it is important to distinguish the perpendicular displacement with respect to the mean field and to the local magnetic field. We consider how superdiffusion changes the acceleration of CRs in shocks and show how it decreases efficiency of the CRs acceleration in perpendicular shocks. We also demonstrate that in the case when the small-scale magnetic field is generated in the pre-shock region, an efficient acceleration can take place for the CRs streaming without collisions along the magnetic loops.

  4. A cosmic ALP background and the cluster soft X-ray excess in A665, A2199 and A2255

    NASA Astrophysics Data System (ADS)

    Powell, Andrew J.

    2015-09-01

    It has been proposed that an excess in soft X-ray emission observed from many galaxy clusters can be explained by conversion into photons of axion-like particles (ALPs) in the cluster's magnetic field. Previously it has been shown that conversion of this primordially-generated background of relativistic ALPs—a cosmic ALP background (CAB)—can explain the observed soft X-ray excess in both the centre and the outskirts of the Coma cluster. Here we extend this work to the three clusters A665, A2199 and A2255. We use a stochastic, power law model of the cluster magnetic field to numerically calculate ALP-photon conversion probabilities to predict the CAB-generated soft X-ray flux in these clusters. The simulated magnetic fields include models with non-standard (i.e. not turbulent Kolmogorov) power spectra, the index of the spectrum changes from cluster to cluster and even within the cluster A2255. We compare this flux to ROSAT PSPC observations of the three clusters, and use these observations to constrain the CAB parameter space. Assuming these non-standard magnetic field power spectra are valid, we find the CAB can reproduce the magnitude of the observed excess in A2199 and A2255 for the same CAB parameters that match the observed soft excess in the Coma cluster. We also find good fit to the morphology of the excesses in these clusters. Simulation of CAB conversion in the cluster A665 is in mild tension with the other clusters due to producing a small but observable excess at large radii where none is observed. This tension is alleviated considering the uncertainty on predicting the count rate in the ROSAT detector, and on the systematics affecting the magnetic field determination. Overall we find good agreement between the CAB parameters for the four clusters studied so far.

  5. Cosmic ray modulation and merged interaction regions

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Goldstein, M. L.; Mcdonald, F. B.

    1985-01-01

    Beyond several AU, interactions among shocks and streams give rise to merged interaction regions in which the magnetic field is turbulent. The integral intensity of . 75 MeV/Nuc cosmic rays at Voyager is generally observed to decrease when a merged interaction region moves past the spacecraft and to increase during the passage of a rarefaction region. When the separation between interaction regions is relatively large, the cosmic ray intensity tends to increase on a scale of a few months. This was the case at Voyager 1 from July 1, 1983 to May 1, 1984, when the spacecraft moved from 16.7 to 19.6 AU. Changes in cosmic ray intensity were related to the magnetic field strength in a simple way. It is estimated that the diffusion coefficient in merged interaction regions at this distance is similar to 0.6 x 10 to the 22nd power sq cm/s.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  7. CORE-COLLAPSE MODEL OF BROADBAND EMISSION FROM SNR RX J1713.7-3946 WITH THERMAL X-RAYS AND GAMMA RAYS FROM ESCAPING COSMIC RAYS

    SciTech Connect

    Ellison, Donald C.; Slane, Patrick; Patnaude, Daniel J.; Bykov, Andrei M. E-mail: byk@astro.ioffe.ru

    2012-01-01

    We present a spherically symmetric, core-collapse model of SNR RX J1713.7-3946 that includes a hydrodynamic simulation of the remnant evolution coupled to the efficient production of cosmic rays (CRs) by nonlinear diffusive shock acceleration. High-energy CRs that escape from the forward shock (FS) are propagated in surrounding dense material that simulates either a swept-up, pre-supernova shell or a nearby molecular cloud. The continuum emission from trapped and escaping CRs, along with the thermal X-ray emission from the shocked heated interstellar medium behind the FS, integrated over the remnant, is compared against broadband observations. Our results show conclusively that, overall, the GeV-TeV emission is dominated by inverse-Compton from CR electrons if the supernova is isolated regardless of its type, i.e., not interacting with a >>100 M{sub Sun} shell or cloud. If the supernova remnant is interacting with a much larger mass {approx}> 10{sup 4} M{sub Sun }, pion decay from the escaping CRs may dominate the TeV emission, although a precise fit at high energy will depend on the still uncertain details of how the highest energy CRs are accelerated by, and escape from, the FS. Based on morphological and other constraints, we consider the 10{sup 4} M{sub Sun} pion-decay scenario highly unlikely for SNR RX J1713.7-3946 regardless of the details of CR escape. Importantly, even though CR electrons dominate the GeV-TeV emission, the efficient production of CR ions is an essential part of our leptonic model.

  8. Cosmic Rays and Global Warming

    SciTech Connect

    Sloan, T.; Wolfendale, A. W.

    2008-01-24

    Some workers have claimed that the observed temporal correlations of (low level) terrestrial cloud cover with the cosmic ray intensity changes, due to solar modulation, are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim in some detail. So far, we have not found any evidence in support and so our conclusions are to doubt it. From the absence of corroborative evidence we estimate that less than 15% at the 95% confidence level, of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 43 years is due to this cause. The origin of the correlation itself is probably the cycle of solar irradiance although there is, as yet, no certainty.

  9. Efficacy of Cosmic Ray Shields

    NASA Astrophysics Data System (ADS)

    Rhodes, Nicholas

    2015-10-01

    This research involved testing various types of shielding with a self-constructed Berkeley style cosmic ray detector, in order to evaluate the materials of each type of shielding's effectiveness at blocking cosmic rays and the cost- and size-efficiency of the shields as well. The detector was constructed, then tested for functionality and reliability. Following confirmation, the detector was then used at three different locations to observe it altitude or atmospheric conditions had any effect on the effectiveness of certain shields. Multiple types of shielding were tested with the detector, including combinations of several shields, primarily aluminum, high-iron steel, polyethylene plastic, water, lead, and a lead-alternative radiation shield utilized in radiology. These tests regarding both the base effectiveness and the overall efficiency of shields is designed to support future space exploratory missions where the risk of exposure to possibly lethal amounts of cosmic rays for crew and the damage caused to unshielded electronics are of serious concern.

  10. Nonlinear Cosmic Ray Diffusion Theories

    NASA Astrophysics Data System (ADS)

    Shalchi, Andreas

    Within cosmic ray transport theory, we investigate the interaction between energetic charged particles like electrons, protons, or heavy ions and astrophysical plasmas such as the solar wind or the interstellar medium. These particles interact with a background magnetic field B 0 and with turbulent electric and magnetic fields ýE and ýB, and they therefore experience scattering parallel and perpendicular to B 0. In this introductory chapter, general properties of cosmic rays are discussed, as well as the unperturbed motion of the particles. Furthermore, the physics of parallel and perpendicular scattering is investigated. At the end of this chapter, we consider observed mean free paths of cosmic rays in the heliosphere and in the interstel- lar medium. One aim of this book is to demonstrate that a nonlinear description of particle transport is necessary to reproduce these measurements.

  11. The origin of galactic cosmic rays

    NASA Astrophysics Data System (ADS)

    Blasi, Pasquale

    2013-11-01

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

  12. Fun Times with Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

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

  13. Aligned interactions in cosmic rays

    NASA Astrophysics Data System (ADS)

    Kempa, J.

    2015-12-01

    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.

  14. Aligned interactions in cosmic rays

    SciTech Connect

    Kempa, J.

    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.

  15. The microphysics and macrophysics of cosmic rays

    SciTech Connect

    Zweibel, Ellen G.

    2013-05-15

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

  16. Cosmic X-rays Reveal Evidence For New Form Of Matter

    NASA Astrophysics Data System (ADS)

    2002-04-01

    NASA's Chandra X-ray Observatory has found two stars -- one too small, one too cold -- that reveal cracks in our understanding of the structure of matter. These discoveries open a new window on nuclear physics, offering a link between the vast cosmos and its tiniest constituents. Chandra's observations of RX J1856.5-3754 and 3C58 suggest that the matter in these stars is even denser than nuclear matter found on Earth. This raises the possibility these stars are composed of pure quarks or contain crystals of sub-nuclear particles that normally have only a fleeting existence following high-energy collisions. By combining Chandra and Hubble Space Telescope data, astronomers found that RX J1856 radiates like a solid body with a temperature of 1.2 million degrees Fahrenheit (700,000 degrees Celsius) and has a diameter of about seven miles (11.3 kilometers). This size is too small to reconcile with standard models for neutron stars -- until now the most extreme form of matter known. "Taken at face value, the combined observational evidence points to a star composed not of neutrons, but of quarks in a form known as strange quark matter," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., and lead author of a paper on RX J1856 to appear in the June 20, 2002, issue of The Astrophysical Journal. "Quarks, thought to be the fundamental constituents of nuclear particles, have never been seen outside a nucleus in Earth-bound laboratories." Observations by Chandra of 3C58 also yielded startling results. A team composed of Patrick Slane and Steven Murray, also of CfA, and David Helfand of Columbia University, New York, failed to detect the expected X-radiation from the hot surface of 3C58, a neutron star believed to have been created in an explosion witnessed by Chinese and Japanese astronomers in A.D. 1181. The team concluded that the star has a temperature of less than one million degrees Celsius, which is far below the predicted

  17. The Heliosphere and Galactic Cosmic Rays

    NASA Video Gallery

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

  18. Evaluation of Galactic Cosmic Ray Models

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  19. Cosmic rays and hadronic interactions

    NASA Astrophysics Data System (ADS)

    Lipari, Paolo

    2015-08-01

    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.

  20. Cosmic Ray Energetics And Mass

    NASA Astrophysics Data System (ADS)

    Seo, Eun-Suk

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

  1. The Cosmic Ray Electron Excess

    NASA Technical Reports Server (NTRS)

    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.

  2. EFFICIENT COSMIC RAY ACCELERATION, HYDRODYNAMICS, AND SELF-CONSISTENT THERMAL X-RAY EMISSION APPLIED TO SUPERNOVA REMNANT RX J1713.7-3946

    SciTech Connect

    Ellison, Donald C.; Patnaude, Daniel J.; Slane, Patrick; Raymond, John

    2010-03-20

    We model the broadband emission from supernova remnant (SNR) RX J1713.7-3946 including, for the first time, a consistent calculation of thermal X-ray emission together with non-thermal emission in a nonlinear diffusive shock acceleration model. Our model tracks the evolution of the SNR including the plasma ionization state between the forward shock and the contact discontinuity. We use a plasma emissivity code to predict the thermal X-ray emission spectrum assuming the initially cold electrons are heated either by Coulomb collisions with the shock-heated protons (the slowest possible heating), or come into instant equilibration with the protons. For either electron heating model, electrons reach {approx}>10{sup 7} K rapidly and the X-ray line emission near 1 keV is more than 10 times as luminous as the underlying thermal bremsstrahlung continuum. Since recent Suzaku observations show no detectable line emission, this places strong constraints on the unshocked ambient medium density and on the relativistic electron-to-proton ratio. For the uniform circumstellar medium (CSM) models that we consider, the low densities and high relativistic electron-to-proton ratios required to match the Suzaku X-ray observations definitively rule out pion decay as the emission process producing GeV-TeV photons. We show that leptonic models, where inverse-Compton scattering against the cosmic background radiation dominates the GeV-TeV emission, produce better fits to the broadband thermal and non-thermal observations in a uniform CSM.

  3. Low-Energy Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Wiedenbeck, M. E.; ACE/CRIS Collaboration

    2002-12-01

    Cosmic rays with energies below about 10 GeV/nucleon have been measured with high precision as a result of experiments on the HEAO, Ulysses, and ACE spacecrafts. The observations provide energy spectra, elemental abundances, and isotopic composition for elements up through Z=30. They include both stable and radioactive nuclides that are synthesized in stars or are produced by nuclear fragmentation during diffusion at high energies through interstellar medium. From these data one obtains a rather detailed picture of the origin of low-energy cosmic rays. For refractory species, the cosmic-ray source composition closely resembles that of the Sun, suggesting that cosmic rays are accelerated from a well-mixed sample of interstellar matter. A chemical fractionation process has depleted the abundances of volatile elements relative to refractories. Using various radioactive clock isotopes it has been shown that particle acceleration occurs at least 105 years after supernova nucleosynthesis and that the accelerated particles diffuse in the Galaxy for approximately 15 Myr after acceleration. Energy spectra and secondary-to-primary ratios are reasonably well accounted for by models in which particles gain the bulk of their energy in a single encounter with a strong shock. Among the large number of species that have been measured, 22Ne stands out as the only nuclide with an abundance that is clearly much different than solar. To test models proposed to account for this anomaly, the data are being analyzed for predicted smaller effects on abundances of other nuclides. In addition to providing a detailed understanding of the origin and acceleration of low-energy cosmic rays, these data are providing constraints on the chemical evolution of interstellar matter. This work was supported by NASA at Caltech (under grant NAG5-6912), JPL, NASA/GSFC, and Washington U.

  4. Research in cosmic and gamma ray astrophysics

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  5. A new measurement of the cosmic ray energy spectrum between 3 x 10 to the 15th power eV and 3 x 10 to the 16th power eV

    NASA Technical Reports Server (NTRS)

    Gregory, A. G.; Patterson, J. R.; Protheroe, R. J.

    1985-01-01

    A new Cerenkov photon density spectrum measurement is reported. The derivation of the primary cosmic ray energy spectrum for energies from 3x10 to the 15th power eV to 3x10 to the 16th power eV are presented.

  6. High-energy X-ray detection of G359.89–0.08 (SGR A–E): Magnetic flux tube emission powered by cosmic rays?

    SciTech Connect

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

    2014-03-20

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

  7. A Cerenkov - Delta E/Delta X experiment for measuring cosmic-ray isotopes from neon through iron

    NASA Technical Reports Server (NTRS)

    Buffington, A.; Lau, K.; Schindler, S. M.; Stone, E. C.; Laursen, S.; Rasmussen, I. L.

    1983-01-01

    Cosmic-ray isotope masses are measured in a balloon-borne cosmic-ray experiment. Two Cerenkov counters and an NaI scintillator stack are used to determine changes in energy and in the Lorentz factor for a traversing or stopping particle. The mass is defined at the ratio of the change in energy to the change in the Lorentz factor. For incident elements from neon through iron, mass resolution better than 0.3 a.m.u. is expected, with incident Lorentz gammas ranging from 2.4 to 3.1, depending on the element. The mass resolution is approximately 0.2 a.m.u., measured for Mn-55 ions having an incident Lorentz factor of 2.75.

  8. Cosmic Ray Observatories for Space Weather Studies.

    NASA Astrophysics Data System (ADS)

    González, Xavier

    2016-07-01

    The Mexican Space Weather Service (SCiESMEX) was created in October 2014. Some observatories measure data for the service at different frequencies and particles. Two cosmic ray observatories detect the particle variations attributed to solar emissions, and are an important source of information for the SCiESMEX. The Mexico City Cosmic Ray Observatory consists of a neutron monitor (6-NM-64) and a muon telescope, that detect the hadronic and hard component of the secondary cosmic rays in the atmosphere. It has been in continous operation since 1990. The Sierra Negra Cosmic Ray Observatory consists of a solar neutron telescope and the scintillator cosmic ray telescope. These telescopes can detect the neutrons, generated in solar flares and the hadronic and hard components of the secondary cosmic rays. It has been in continous operation since 2004. We present the two observatories and the capability to detect variations in the cosmic rays, generated by the emissions of the solar activity.

  9. Cosmic Ray and Tev Gamma Ray Generation by Quasar Remnants

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  10. Characterising CCDs with cosmic rays

    SciTech Connect

    Fisher-Levine, M.; Nomerotski, A.

    2015-08-06

    The properties of cosmic ray muons make them a useful probe for measuring the properties of thick, fully depleted CCD sensors. The known energy deposition per unit length allows measurement of the gain of the sensor's amplifiers, whilst the straightness of the tracks allows for a crude assessment of the static lateral electric fields at the sensor's edges. The small volume in which the muons deposit their energy allows measurement of the contribution to the PSF from the diffusion of charge as it drifts across the sensor. In this work we present a validation of the cosmic ray gain measurement technique by comparing with radioisotope gain measurments, and calculate the charge diffusion coefficient for prototype LSST sensors.

  11. Characterising CCDs with cosmic rays

    DOE PAGESBeta

    Fisher-Levine, M.; Nomerotski, A.

    2015-08-06

    The properties of cosmic ray muons make them a useful probe for measuring the properties of thick, fully depleted CCD sensors. The known energy deposition per unit length allows measurement of the gain of the sensor's amplifiers, whilst the straightness of the tracks allows for a crude assessment of the static lateral electric fields at the sensor's edges. The small volume in which the muons deposit their energy allows measurement of the contribution to the PSF from the diffusion of charge as it drifts across the sensor. In this work we present a validation of the cosmic ray gain measurementmore » technique by comparing with radioisotope gain measurments, and calculate the charge diffusion coefficient for prototype LSST sensors.« less

  12. Cosmic Ray research in Armenia

    NASA Astrophysics Data System (ADS)

    Chilingarian, A.; Mirzoyan, R.; Zazyan, M.

    2009-11-01

    Cosmic Ray research on Mt. Aragats began in 1934 with the measurements of East-West anisotropy by the group from Leningrad Physics-Technical Institute and Norair Kocharian from Yerevan State University. Stimulated by the results of their experiments in 1942 Artem and Abraham Alikhanyan brothers organized a scientific expedition to Aragats. Since that time physicists were studying Cosmic Ray fluxes on Mt. Aragats with various particle detectors: mass spectrometers, calorimeters, transition radiation detectors, and huge particle detector arrays detecting protons and nuclei accelerated in most violent explosions in Galaxy. Latest activities at Mt. Aragats include Space Weather research with networks of particle detectors located in Armenia and abroad, and detectors of Space Education center in Yerevan.

  13. Characterising CCDs with cosmic rays

    NASA Astrophysics Data System (ADS)

    Fisher-Levine, M.; Nomerotski, A.

    2015-08-01

    The properties of cosmic ray muons make them a useful probe for measuring the properties of thick, fully depleted CCD sensors. The known energy deposition per unit length allows measurement of the gain of the sensor's amplifiers, whilst the straightness of the tracks allows for a crude assessment of the static lateral electric fields at the sensor's edges. Furthermore, the small volume in which the muons deposit their energy allows measurement of the contribution to the PSF from the diffusion of charge as it drifts across the sensor. In this work we present a validation of the cosmic ray gain measurement technique by comparing with radioisotope gain measurments, and calculate the charge diffusion coefficient for prototype LSST sensors.

  14. Antiprotons in the Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Nutter, Scott

    1999-10-01

    The HEAT (High Energy Antimatter Telescope) collaboration flew in May 1999 a balloon-borne instrument to measure the relative abundance of antiprotons and protons in the cosmic rays to kinetic energies of 30 GeV. The instrument uses a multiple energy loss technique to measure the Lorentz factor of through-going cosmic rays, a magnet spectrometer to measure momentum, and several scintillation counters to determine particle charge and direction (up or down in the atmosphere). The antiproton/proton abundance ratio as a function of energy is a probe of the propagation environment of protons through the galaxy. Existing measurements indicate a higher than expected value at both high and low energies. A confirming measurement could indicate peculiar antiproton sources, such as WIMPs or supersymmetric darkmatter candidates. A description of the instrument, details of the flight and instrument performance, and status of the data analysis will be given.

  15. Cosmic ray variations during PCA type absorption

    NASA Technical Reports Server (NTRS)

    Kozin, I. D.

    1972-01-01

    It is shown based on data on the cosmic-ray neutron component, ionospheric soundings, and measurements of cosmic radio-emission absorption at Vostok station (Antarctica) that the ionization of the lower ionosphere increases during low intensity of Forbush-type cosmic rays. This is manifested in increased absorption and the appearance of strong sporadic layers in the E-region.

  16. Charged Cosmic Rays and Neutrinos

    NASA Astrophysics Data System (ADS)

    Kachelrieß, M.

    2013-04-01

    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".

  17. Cosmic Ray Energetics And Mass

    NASA Astrophysics Data System (ADS)

    Seo, Eun-Suk

    2014-08-01

    The balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment was flown for ~161 days in six flights over Antarctica. High energy cosmic-ray data were collected over a wide energy range from ~ 10^10 to > 10^14 eV at an average altitude of ~38.5 km with ~3.9 g/cm2 atmospheric overburden. Cosmic-ray elements from protons (Z = 1) to iron nuclei (Z = 26) are separated with excellent charge resolution. Building on success of the balloon flights, the payload is being reconfigured for exposure on the International Space Station (ISS). This ISS-CREAM instrument is configured with the CREAM calorimeter for energy measurements, and four finely segmented Silicon Charge Detector layers for precise charge measurements. In addition, the Top and Bottom Counting Detectors (TCD and BCD) and Boronated Scintillator Detector (BSD) have been newly developed. The TCD and BCD are scintillator based segmented detectors to separate electrons from nuclei using the shower profile differences, while BSD distinguishes electrons from nuclei by detecting thermal neutrons that are dominant in nuclei induced showers. An order of magnitude increase in data collecting power is possible by utilizing the ISS to reach the highest energies practical with direct measurements. The project status including results from on-going analysis of existing data and future plans will be discussed.

  18. Ionisation as indicator for cosmic ray acceleration

    NASA Astrophysics Data System (ADS)

    Schuppan, F.; Röken, C.; Fedrau, N.; Becker Tjus, J.

    2014-06-01

    Astrospheres and wind bubbles of massive stars are believed to be sources of cosmic rays with energies E ≲ 1 TeV. These particles are not directly detectable, but their impact on surrounding matter, in particular ionisation of atomic and molecular hydrogen, can lead to observable signatures. A correlation study of both gamma ray emission, induced by proton-proton interactions of cosmic ray protons with kinetic energies Ep ≥ 280 MeV with ambient hydrogen, and ionisation induced by cosmic ray protons of kinetic energies Ep < 280 MeV can be performed in order to study potential sources of (sub)TeV cosmic rays.

  19. Stopping Cooling Flows with Cosmic-Ray Feedback

    NASA Astrophysics Data System (ADS)

    Mathews, William G.

    2009-04-01

    Multi-Gyr two-dimensional calculations describe the gas dynamical 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 1059 erg lasting 20 Myr and spaced at intervals of 200 Myr, the central cooling rate is greatly reduced to {\\dot{M}} ≈ 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 Gyr the hot gas density and temperature profiles remain similar to those observed, provided the time-averaged cosmic-ray luminosity is about L cr = 2.7 × 1043 erg s-1, approximately equal to the bolometric cooling rate LX within only ~56kpc. If an appreciable fraction of the relativistic cosmic rays is protons, gamma rays produced by pion decay following inelastic p-p collisions may be detected with the Fermi Gamma-Ray Telescope.

  20. Galactic cosmic ray composition and energy spectra

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.

    1994-01-01

    Galactic cosmic ray nuclei represent a significant risk to long-duration spaceflight outside the magnetosphere. We review briefly existing measurements of the composition and energy spectra of heavy cosmic ray nuclei, pointing out which species and energy ranges are most critical to assessing cosmic ray risks for spaceflight. Key data sets are identified and a table of cosmic ray abundances is presented for elements from H to Ni (Z = 1 to 28). Because of the 22-year nature of the solar modulation cycle, data from the approaching 1998 solar minimum is especially important to reducing uncertainties in the cosmic ray radiation hazard. It is recommended that efforts to model this hazard take advantage of approaches that have been developed to model the astrophysical aspects of cosmic rays.

  1. Underground measurements on secondary cosmic rays

    NASA Technical Reports Server (NTRS)

    Fenton, A. G.; Wilson, C. W.; Fenton, K. B.

    1985-01-01

    Measurements made at the Poatina cosmic ray station (41.8 S 149.9 E, 347 m.w.e.) from August 1983 to July 1984 are summarized. The cosmic ray primary particles responsible for events detected at the station have a median primary energy of 1.2 TeV. The motivation for part of this work came from the reported detection of narrow angle anisotropies in the arrival direction of cosmic rays.

  2. Cloud chamber visualization of primary cosmic rays

    SciTech Connect

    Earl, James A.

    2013-02-07

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

  3. Deuterium and He-3 in cosmic rays

    NASA Technical Reports Server (NTRS)

    Stephens, S. A.

    1989-01-01

    Observation of a large flux of antiprotons in cosmic rays prompted many to postulate new ideas relating to the origin and propagation of cosmic rays in the Galaxy, within the framework of the secondary hypothesis. Under this hypothesis, cosmic rays traverse a large amount of matter either in the source region or in the interstellar space. As a result, large amounts of deuterium and He-3 are also produced as a consequence of spallation of helium and heavier nuclei. In this paper, the spectra of these isotopes are derived, using various models for the propagation of cosmic rays and compare with the existing observations.

  4. Propagation of cosmic rays in the galaxy

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  5. High-energy cosmic ray interactions

    SciTech Connect

    Engel, Ralph; Orellana, Mariana; Reynoso, Matias M.; Vila, Gabriela S.

    2009-04-30

    Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand--due to the indirect observation of cosmic rays through air showers--the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

  6. Anuradha and low-energy cosmic rays

    NASA Technical Reports Server (NTRS)

    Biswas, S.; Durgaprasad, N.; Mitra, Banashree; Dutta, A.

    1993-01-01

    After critically reviewing observational results obtained by astronomical spacecraft in the interplanetary medium for several aspects of galactic cosmic rays (GCRs) and anomalous cosmic rays (ACRs), attention is given to spacecraft data gathered in the magnetosphere and a detailed description is given of the Anuradha cosmic-ray experiment carried by Spacelab-3. The Anuradha results discussed concern the orbit average flux and ionization state of ACRs, the origins of partially ionized galactic cosmic-ray sub-Fe and Fe ions, and the significance of enhanced abundance ratios of sub-Fe and Fe ions in GCRs inside the magnetosphere.

  7. A hysteresis effect in cosmic ray modulation

    NASA Technical Reports Server (NTRS)

    Verschell, H. J.; Mendell, R. B.; Korff, S. A.

    1974-01-01

    The rigidity dependence is investigated in the modulation of cosmic ray protons and alphas at intermediate (2-13 Gv) rigidities during the declines and recoveries of the cosmic ray flux near cosmic ray minimum. The results include the finding that sudden changes in the modulation of the primary cosmic rays are initiated by large solar particle outflow and begin as type I Forbush decreases. Typically, the modulation spectrum becomes flatter at intermediate rigidity below 13 Gv and steeper at rigidities above 13 Gv during early recovery.

  8. A Journey Through Researches on Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Bhattacharya, R.; Roy, M.; Barman, P.; Mukherjee, C. D.

    2013-04-01

    Cosmic ray causes hazards to microelectronic circuits. Presence of charged particles in the atmosphere was first noticed by Coloumb in 1785. But cosmic ray was discovered by Victor Hess in 1912. However new era of particle physics was started with the invention of neutron monitor in 1948 by John A. Simpson. New information regarding the energy spectrum, anisotropy, latitudinal, longitudinal and daily variation of cosmic ray has added the scientific yield one by one from the analysis of the data of different monitors over the globe. This paper is a brief account of the striking events of cosmic ray which may be the background of future researchers.

  9. Cosmic Rays in the Heliosphere

    NASA Astrophysics Data System (ADS)

    Potgieter, M. S.

    The international heliospheric year (IHY) has the purpose to promote research on the Sun-Heliosphere system outward to the local interstellar medium - the new frontier. This includes fostering international scientific cooperation in the study of heliophysical phenomena now and in the future. Part of this process is to communicate research done on the heliosphere, especially to the scientific community in Africa. A short review is given of the numerical modeling of the heliosphere, and of the modulation of cosmic rays and how these particles are used to probe the heliosphere to understand its basic features. Projects of both a theoretical and numerical nature are proposed for the IHY.

  10. Cosmic ray charge and energy spectrum measurements using a new large area Cerenkov x dE/dx telescope

    NASA Technical Reports Server (NTRS)

    Schrier, D. A.; Webber, W. R.; Kish, J. C.

    1985-01-01

    In September, 1981, a new 0.5 square meter ster cosmic ray telescope was flown to study the charge composition and energy spectrum of cosmic ray nuclei between 0.3 and 4 GeV/nuc. A high resolution Cerenkov counter, and three dE/dx measuring scintillation counters, including two position scintillators were contained in the telescope used for the charge and energy spectrum measurements. The analysis procedures did not require any large charge or energy dependent corrections, and absolute fluxes could be obtained to an accuracy approximately 5%. The spectral measurements made in 1981, at a time of extreme solar modulation, could be compared with measurements with a similar telescope made by our group in 1977, at a time of minimum modulation and can be used to derive absolute intensity values for the HEAO measurements made in 1979 to 80. Using both data sets precise energy spectra and abundance ratios can be derived over the entire energy range from 0.3 to greater than 15 GeV/nuc.

  11. Cosmic-ray acceleration at stellar wind terminal shocks

    NASA Technical Reports Server (NTRS)

    Webb, G. M.; Axford, W. I.; Forman, M. A.

    1985-01-01

    Steady-state spherically symmetric analytic solutions of the cosmic-ray transport equations, applicable to the problem of acceleration of cosmic rays at the terminal shock to a stellar wind, are studied. The spectra, graidents, and flow patterns of particles modulated and accelerated by the stellar wind and shock are investigated by means of monoenergetic-source solutions at finite radius, as well as solutions with monoenergetic and power-law galactic spectra. On the basis of calculations given, early-type stars could supply a significant fraction of the 3 x 10 to the 40th ergs/sec required by galactic cosmic rays.

  12. Acceleration of cosmic rays in Tycho's SNR.

    NASA Astrophysics Data System (ADS)

    Morlino, G.; Caprioli, D.

    We apply the non-linear diffusive shock acceleration theory in order to describe the properties of SN 1572 (G120.1+1.4, hereafter simply Tycho). By analyzing its multi-wavelength spectrum, we show how Tycho's forward shock (FS) is accelerating protons up to ˜ 500 TeV, channeling into cosmic rays more than 10 per cent of its kinetic energy. We find that the streaming instability induced by cosmic rays is consistent with all the observational evidences indicating a very efficient magnetic field amplification (up to ˜ 300 mu G), in particular the X-ray morphology of the remnant. We are able to explain the gamma-ray spectrum from the GeV up to the TeV band, recently measured respectively by Fermi-LAT and VERITAS, as due to pion decay produced in nuclear collisions by accelerated nuclei scattering against the background gas. We also show that emission due to the accelerated electrons does not play a relevant role in the observed gamma-ray spectrum.

  13. Inverse Compton X-Ray Halos Around High-z Radio Galaxies: A Feedback Mechanism Powered by Far-Infrared Starbursts or the Cosmic Microwave Background?

    NASA Technical Reports Server (NTRS)

    Small, Ian; Blundell, Katherine M.; Lehmer, B. D.; Alexander, D. M.

    2012-01-01

    We report the detection of extended X-ray emission around two powerful radio galaxies at z approx. 3.6 (4C 03.24 and 4C 19.71) and use these to investigate the origin of extended, inverse Compton (IC) powered X-ray halos at high redshifts. The halos have X-ray luminosities of L(sub X) approx. 3 x 10(exp 44) erg/s and sizes of approx.60 kpc. Their morphologies are broadly similar to the approx.60 kpc long radio lobes around these galaxies suggesting they are formed from IC scattering by relativistic electrons in the radio lobes, of either cosmic microwave background (CMB) photons or far-infrared photons from the dust-obscured starbursts in these galaxies. These observations double the number of z > 3 radio galaxies with X-ray-detected IC halos. We compare the IC X-ray-to-radio luminosity ratios for the two new detections to the two previously detected z approx. 3.8 radio galaxies. Given the similar redshifts, we would expect comparable X-ray IC luminosities if millimeter photons from the CMB are the dominant seed field for the IC emission (assuming all four galaxies have similar ages and jet powers). Instead we see that the two z approx. 3.6 radio galaxies, which are 4 fainter in the far-infrared than those at z 3.8, also have approx.4x fainter X-ray IC emission. Including data for a further six z > or approx. 2 radio sources with detected IC X-ray halos from the literature, we suggest that in the more compact, majority of radio sources, those with lobe sizes < or approx.100-200 kpc, the bulk of the IC emission may be driven by scattering of locally produced far-infrared photons from luminous, dust-obscured starbursts within these galaxies, rather than millimeter photons from the CMB. The resulting X-ray emission appears sufficient to ionize the gas on approx.100-200 kpc scales around these systems and thus helps form the extended, kinematically quiescent Ly(alpha) emission line halos found around some of these systems. The starburst and active galactic nucleus

  14. Origin of high energy Galactic cosmic rays

    NASA Technical Reports Server (NTRS)

    Gaisser, T. K.

    1990-01-01

    The flux of cosmic ray antiprotons and the chemical composition in the region of the 'knee' of the cosmic ray energy spectrum are discussed. The importance of a direct determination of the energy spectrum of each major component of cosmic radiation through the knee region is stressed, and the necessary kinds of experiments are described. It is emphasized that antiprotons are a unique probe of acceleration and propagation of energetic particles in the galaxy because of the high threshold for their production.

  15. The Origin of Cosmic Rays: What can GLAST Say?

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  16. Early history of cosmic rays at Chicago

    NASA Astrophysics Data System (ADS)

    Yodh, Gaurang B.

    2013-02-01

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

  17. History of cosmic ray research in Finland

    NASA Astrophysics Data System (ADS)

    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.

  18. Research in cosmic and gamma ray astrophysics

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  19. Cosmic-Ray Modulation Equations

    NASA Astrophysics Data System (ADS)

    Moraal, H.

    2013-06-01

    The temporal variation of the cosmic-ray intensity in the heliosphere is called cosmic-ray modulation. The main periodicity is the response to the 11-year solar activity cycle. Other variations include a 27-day solar rotation variation, a diurnal variation, and irregular variations such as Forbush decreases. General awareness of the importance of this cosmic-ray modulation has greatly increased in the last two decades, mainly in communities studying cosmogenic nuclides, upper atmospheric physics and climate, helio-climatology, and space weather, where corrections need to be made for these modulation effects. Parameterized descriptions of the modulation are even used in archeology and in planning the flight paths of commercial passenger jets. The qualitative, physical part of the modulation is generally well-understood in these communities. The mathematical formalism that is most often used to quantify it is the so-called Force-Field approach, but the origins of this approach are somewhat obscure and it is not always used correct. This is mainly because the theory was developed over more than 40 years, and all its aspects are not collated in a single document. This paper contains a formal mathematical description intended for these wider communities. It consists of four parts: (1) a description of the relations between four indicators of "energy", namely energy, speed, momentum and rigidity, (2) the various ways of how to count particles, (3) the description of particle motion with transport equations, and (4) the solution of such equations, and what these solutions mean. Part (4) was previously described in Caballero-Lopez and Moraal (J. Geophys. Res, 109: A05105, doi: 10.1029/2003JA010358, 2004). Therefore, the details are not all repeated here. The style of this paper is not to be rigorous. It rather tries to capture the relevant tools to do modulation studies, to show how seemingly unrelated results are, in fact, related to one another, and to point out the

  20. High energy physics in cosmic rays

    SciTech Connect

    Jones, Lawrence W.

    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.

  1. Investigation of Reacceleration on Cosmic Ray

    NASA Astrophysics Data System (ADS)

    Lu, Yuxi; Picot-Clemente, Nicolas; Seo, Eun-Suk

    2016-03-01

    Cosmic rays are high energy charged particles, originating from outer space, that travel at nearly the speed of light and strike the Earth from all directions. One century after the discovery of cosmic rays, their origin and propagation processes remain obscure. GALPROP is a numerical code for calculating the propagation of relativistic charged particles and the diffuse emissions produced during their propagation in the Galaxy. I performed a preliminary study using two different propagation models with the GALPROP code in order to reproduce latest cosmic-ray nuclei measurements. I analyzed multiple propagation parameters for each model, studied their effect on cosmic-ray spectra, optimized and tried a preliminary modification of the code to fit cosmic-ray data such as BESS-Polar, AMS, CREAM, etc.

  2. Anisotropy and corotation of galactic cosmic rays.

    PubMed

    Amenomori, M; Ayabe, S; Bi, X J; Chen, D; Cui, S W; Danzengluobu; Ding, L K; Ding, X H; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gao, X Y; Geng, Q X; Guo, H W; He, H H; He, M; Hibino, K; Hotta, N; Hu, Haibing; 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; Lu, 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; Saito, 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, L; 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; Zhang, Yi; Zhaxisangzhu; Zhou, X X

    2006-10-20

    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. PMID:17053141

  3. SLAC Cosmic Ray Telescope Facility

    SciTech Connect

    Va'vra, J.

    2010-02-15

    SLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers.

  4. Galactic and solar cosmic rays - Variations and origin

    NASA Astrophysics Data System (ADS)

    Belov, A. V.; Blokh, Ia. L.; Gushchina, R. T.; Dorman, I. V.; Dorman, L. I.

    Past and current research efforts at IZMIRAN (the Soviet Institute for the Study of Terrestrial Magnetism, the Ionosphere, and the Propagation of Radio Waves) on galactic and solar cosmic rays is reviewed. Particular attention is given to investigations of penumbra effects manifested in cosmic rays, long-term cosmic-ray variations, cosmic-ray anisotropy, cosmic-ray fluctuations, the possible relationship between cosmic-ray variations and atmospheric ozone, the stellar anisotropy of cosmic rays, and cosmic-ray propagation in the interstellar medium.

  5. Cosmic Ray Observation for Nuclear Astrophysics:. Corona Program

    NASA Astrophysics Data System (ADS)

    Hasebe, Nobuyuki; Kobayashi, M. N.

    2003-04-01

    Cosmic Ray Observation for Nuclei Astrophysics (CORONA) program is a large-scaled spacecraft or space station approach for nuclear composition of relativistic cosmic rays 10 ≦ Z ≦ 92 and of low-energy isotopes 1 ≦ Z ≦ 58 in space. A large area Spectrometer for Ultraheavy Nuclear Composition (SUNC) and a Large Isotope Telescope Array (LITA) are proposed in this program. CORONA program focuses on the composition of elements beyond the iron-peak nuclei (Z > 60) and the isotopic composition of ultraheavy particles (Z > 30) in galactic cosmic rays as well as solar and interplanetary particles. The observation of nuclear composition covers a wide range of scientific themes including studies of nucleosynthesis of cosmic ray sources, chemical evolution of galactic material, the characteristic time of cosmic rays, heating and acceleration mechanism of cosmic ray particles. Observation of solar particle events also make clear the physical process of transient solar events emitting wide range of radio, X-ray/gamma-ray, plasma and energetic particle radiation, and particle acceleration mechanism driven by CME.

  6. Chest x-ray

    MedlinePlus

    ... Images Aortic rupture, chest x-ray Lung cancer, frontal chest x-ray Adenocarcinoma - chest x-ray Coal ... cancer - chest x-ray Lung nodule, right middle lobe - chest x-ray Lung mass, right upper lung - ...

  7. Multiwavelength Signatures of Cosmic Ray Acceleration by Young Supernova Remnants

    SciTech Connect

    Vink, Jacco

    2008-12-24

    An overview is given of multiwavelength observations of young supernova remnants, with a focus on the observational signatures of efficient cosmic ray acceleration. Some of the effects that may be attributed to efficient cosmic ray acceleration are the radial magnetic fields in young supernova remnants, magnetic field amplification as determined with X-ray imaging spectroscopy, evidence for large post-shock compression factors, and low plasma temperatures, as measured with high resolution optical/UV/X-ray spectroscopy. Special emphasis is given to spectroscopy of post-shock plasma's, which offers an opportunity to directly measure the post-shock temperature. In the presence of efficient cosmic ray acceleration the post-shock temperatures are expected to be lower than according to standard equations for a strong shock. For a number of supernova remnants this seems indeed to be the case.

  8. Cosmic ray interactions in starbursting galaxies

    NASA Astrophysics Data System (ADS)

    Yoast-Hull, Tova M.

    High quality gamma-ray and radio observations of nearby galaxies offer an unprecedented opportunity to quantitatively study the properties of their cosmic ray populations. Accounting for various interactions and energy losses, I developed a multi-component, single-zone model of the cosmic ray populations in the central molecular zones of star-forming galaxies. Using observational knowledge of the interstellar medium and star formation, I successfully predicted the radio, gamma-ray, and neutrino spectra for nearby starbursts. Using chi-squared tests to compare the models with observational radio and gamma-ray data, I placed constraints on magnetic field strengths, cosmic ray energy densities, and galactic wind (advection) speeds. The initial models were applied to and tested on the prototypical starburst galaxy M82. To further test the model and to explore the differences in environment between starbursts and active galactic nuclei, I studied NGC 253 and NGC 1068, both nearby giant spiral galaxies which have been detected in gamma-rays. Additionally, I demonstrated that the excess GeV energy gamma-ray emission in the Galactic Center is likely not diffuse emission from an additional population of cosmic rays accelerated in supernova remnants. Lastly, I investigated cosmic ray populations in the starburst nuclei of Arp 220, a nearby ultraluminous infrared galaxy which displays a high-intensity mode of star formation more common in young galaxies, and I showed that the nuclei are efficient cosmic-ray proton calorimeters.

  9. Ultra high energy gamma rays, cosmic rays and neutrinos from accreting degenerate stars

    NASA Technical Reports Server (NTRS)

    Brecher, K.; Chanmugam, G.

    1985-01-01

    Super-Eddington accretion for a recently proposed unipolar induction model of cosmic ray acceleration in accreting binary star systems containing magnetic white dwarfs or neutron stars is considered. For sufficiently high accretion rates and low magnetic fields, the model can account for: (1) acceleration of cosmic ray nuclei up to energies of 10 to the 19th power eV; (2) production of more or less normal solar cosmic ray composition; (3) the bulk of cosmic rays observed with energies above 1 TeV, and probably even down to somewhat lower energies as well; and (4) possibly the observed antiproton cosmic ray flux. It can also account for the high ultra high energy (UHE) gamma ray flux observed from several accreting binary systems (including Cygnus X-3), while allowing the possibility of an even higher neutrino flux from these sources, with L sub nu/L sub gamma is approximately 100.

  10. Cosmic-ray exposure ages of chondrules

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    If chondrules were exposed to cosmic rays prior to meteorite compaction, they should retain an excess of cosmogenic noble gases. Beyersdorf-Kuis et al. 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.

  11. Cosmic-ray exposure ages of chondrules

    NASA Astrophysics Data System (ADS)

    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.

  12. Explaining TeV Cosmic-Ray Anisotropies with Non-diffusive Cosmic-Ray Propagation

    NASA Astrophysics Data System (ADS)

    Harding, J. Patrick; Fryer, Chris L.; Mendel, Susan

    2016-05-01

    Constraining the behavior of cosmic ray data observed at Earth requires a precise understanding of how the cosmic rays propagate in the interstellar medium. The interstellar medium is not homogeneous; although turbulent magnetic fields dominate over large scales, small coherent regions of magnetic field exist on scales relevant to particle propagation in the nearby Galaxy. Guided propagation through a coherent field is significantly different from random particle diffusion and could be the explanation of spatial anisotropies in the observed cosmic rays. We present a Monte Carlo code to propagate cosmic particle through realistic magnetic field structures. We discuss the details of the model as well as some preliminary studies which indicate that coherent magnetic structures are important effects in local cosmic-ray propagation, increasing the flux of cosmic rays by over two orders of magnitude at anisotropic locations on the sky. The features induced by coherent magnetic structure could be the cause of the observed TeV cosmic-ray anisotropy.

  13. Sulphur mountain: Cosmic ray intensity records

    SciTech Connect

    Venkatesan, D.; Mathews, T.

    1985-01-01

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

  14. Cross-correlating Cosmic IR and X-ray Background Fluctuations: Evidence of Significant Black Hole Populations Among the CIB Sources

    NASA Technical Reports Server (NTRS)

    Cappelluti, N.; Kashlinsky, A.; Arendt, R. G.; Comastri, A.; Fazio, G. G.; Finoguenov, A.; Hasinger, G.; Mather, J. C.; Miyaji, T; Moseley, S. H.

    2013-01-01

    In order to understand the nature of the sources producing the recently uncovered cosmic infrared background (CIB) fluctuations, we study cross-correlations between the fluctuations in the source-subtracted CIB from Spitzer/IRAC data and the unresolved cosmic X-ray background from deep Chandra observations. Our study uses data from the EGS/AEGIS field, where both data sets cover an approx = 8' x 45' region of the sky. Our measurement is the cross-power spectrum between the IR and X-ray data. The cross-power signal between the IRAC maps at 3.6 micron and 4.5 micron and the Chandra [0.5-2] keV data has been detected, at angular scales approx >20'', with an overall significance of approx = 3.8 sigma and approx. = 5.6 sigma, respectively. At the same time we find no evidence of significant cross-correlations at the harder Chandra bands. The cross-correlation signal is produced by individual IR sources with 3.6 micron and 4.5 micron magnitudes m(sub AB) approx. > 25-26 and [0.5-2] keV X-ray fluxes << 7 × 10(exp -177 erg sq. cm/ s. We determine that at least 15%-25% of the large scale power of the CIB fluctuations is correlated with the spatial power spectrum of the X-ray fluctuations. If this correlation is attributed to emission from accretion processes at both IR and X-ray wavelengths, this implies a much higher fraction of accreting black holes than among the known populations. We discuss the various possible origins for the cross-power signal and show that neither local foregrounds nor the known remaining normal galaxies and active galactic nuclei can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations. local foregrounds, nor the known remaining normal galaxies and active galactic nuclei (AGN) can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations

  15. Gamma-ray astronomy and the origin of cosmic rays

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1978-01-01

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

  16. Cosmic ray transport in astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Schlickeiser, R.

    2015-09-01

    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. Cosmic ray transport in astrophysical plasmas

    SciTech Connect

    Schlickeiser, R.

    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.

  18. Photofraction of a 5 cm x 2 cm BGO scintillator. [bismuth germanate crystal for use in cosmic gamma ray detector

    NASA Technical Reports Server (NTRS)

    Dunphy, P. P.; Forrest, D. J.

    1985-01-01

    The photofraction of a 5.1 cm x 2.0 cm bismuth germanate (BGO) scintillator was measured over a gamma-ray energy range of 0.2 to 6.1 MeV. Several methods, used to minimize the effect of room scattering on the measurement, are discussed. These include a gamma-gamma coincidence technique, a beta-gamma coincidence technique, and the use of sources calibrated with a standard 7.6 cm x 7.6 cm sodium iodide scintillator.

  19. TIROS-N Cosmic Ray study

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  20. The isotopic composition of cosmic-ray beryllium and its implication for the cosmic ray's age

    NASA Technical Reports Server (NTRS)

    Lukasiak, A.; Ferrando, P.; Mcdonald, F. B.; Webber, W. R.

    1994-01-01

    We report a new measurement of the cosmic-ray isotopic composition of beryllium in the low-energy range from 35 to 113 MeV per nucleon. This measurement was made using the High Energy Telescope of the CRS experiment on the Voyager 1 and 2 spacecraft during the time period from 1977 to 1991. In this overall time period of 14 years the average solar modulation level was about 500 MV. The cosmic-ray beryllium isotopes were completely separated with an average mass resolution sigma of 0.185 amu. The isotope fractions of Be-7, Be-9, and Be-10 obtained are 52.4 +/- 2.9%, 43.3 +/- 3.7%, and 4.3 +/- 1.5%, respectively. The measured cosmic-ray abundances of Be-7 and Be-9 are found to be in agreement with calculations based on standard Leaky-Box model for the interstellar propagation of cosmic-ray nuclei using the recent cross sections of the New Mexico-Saclay collaboration. From our observed ratio Be-10/Be = 4.3 +/- 1.5% we deduce an average interstellar density of about 0.28 (+0.14, -0.11) atoms/cu cm, and acosmic-ray lifetime for escape of 27 (+19, -9) x 10(exp 6) years. The surviving fraction of Be-10 is found to be 0.19 +/- 0.07. Modifications to the conclusions of the Leaky-Box model when a diffusion + convection halo model for propagation is used are also considered.

  1. Unveiling the Origin of Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Olinto, Angela V.

    2015-04-01

    The origin of cosmic rays, relativistic particles that range from below GeVs to hundreds of EeVs, is a century old mystery. Extremely energetic phenomena occurring over a wide range of scales, from the Solar System to distant galaxies, are needed to explain the non-thermal particle spectrum that covers over 12 orders of magnitude. Space Missions are the most effective platforms to study the origin and history of these cosmic particles. Current missions probe particle acceleration and propagation in the Solar System and in our Galaxy. This year ISS-CREAM and CALET join AMS in establishing the International Space Station as the most active site for studying the origin of Galactic cosmic rays. These missions will study astrophysical cosmic ray accelerators as well as other possible sources of energetic particles such as dark matter annihilation or decay. In the future, the ISS may also be the site for studying extremely high-energy extragalactic cosmic rays with JEM-EUSO. We review recent results in the quest for unveiling the sources of energetic particles with balloons and space payloads and report on activities of the Cosmic ray Science Interest Group (CosmicSIG) under the Physics of the Cosmos Program Analysis Group (PhysPAG).

  2. JUPITER AS A GIANT COSMIC RAY DETECTOR

    SciTech Connect

    Rimmer, P. B.; Stark, C. R.; Helling, Ch.

    2014-06-01

    We explore the feasibility of using the atmosphere of Jupiter to detect ultra-high-energy cosmic rays (UHECRs). 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 × 10{sup 7} km{sup 2}. We predict that Fermi-LAT should be able to detect events of energy >10{sup 21} eV with fluence 10{sup –7} erg cm{sup –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 ≳ 10{sup 20} eV. Extensive air showers also produce a synchrotron signature that may be measurable by Atacama Large Millimeter/submillimeter Array (ALMA). Simultaneous observations of Jupiter with ALMA and Fermi-LAT could be used to provide broad constraints on the energies of the initiating cosmic rays.

  3. Optical and Ionization Basic Cosmic Ray Detector

    NASA Astrophysics Data System (ADS)

    Felix, Julian; Andrade, Diego A.; Araujo, Aurora C.; Arceo, Luis; Cervantes, Carlos A.; Molina, Jorge A.; Palacios, Luz R.

    2014-03-01

    There are drift tubes, operating in the Geiger mode, to detect ionization radiation and there are Cerenkov radiation detectors based on photomultiplier tubes. Here is the design, the construction, the operation and the characterization of a hybrid detector that combines both a drift tube and a Cerenkov detector, used mainly so far to detect cosmic rays. The basic cell is a structural Aluminum 101.6 cm-long, 2.54 cm X 2.54 cm-cross section, 0.1 cm-thick tube, interiorly polished to mirror and slightly covered with TiCO2, and filed with air, and Methane-Ar at different concentrations. There is a coaxial 1 mil Tungsten wire Au-coated at +700 to +1200 Volts electronically instrumented to read out in both ends; and there is in each end of the Aluminum tube a S10362-11-100U Hamamatsu avalanche photodiode electronically instrumented to be read out simultaneously with the Tungsten wire signal. This report is about the technical operation and construction details, the characterization results and potential applications of this hybrid device as a cosmic ray detector element. CONACYT, Mexico.

  4. Time Variation of Cosmic Ray Arrival Directions

    NASA Astrophysics Data System (ADS)

    Corbett, Henry; Desiati, P.

    2014-01-01

    Experimental data from the IceCube Neutrino Observatory have been used to characterize the anisotropy in the arrival directions of muons produced in cosmic ray air showers. The anisotropy can be fairly well described as a superposition of a dipole and quadrupole of unknown origin in celestial equatorial coordinates. It is also expected to be described as a dipole associated with the Compton-Getting effect in a coordinate system fixed with respect to the Sun. We utilized IceCube data collected from 2008 through 2011, containing 3.69 x 10^10 events with a median cosmic ray particle energy of 20 TeV. We limited our analysis to data from four azimuthal regions, allowing the rotation of the Earth to trace out a periodic signal. We used a Lomb-Scargle periodogram to approximate a frequency spectrum from the event rates. The frequency spectrum contained four peaks with a significance level greater than 5σ, including a peak at 0.997 day^-1 that is consistent with a sideband caused by modulation of the solar dipole. If further analysis confirms this modulation, interference between the solar and sidereal time frames will need to be considered in future analyses of the anisotropy. This work was partially supported by the National Science Foundation's REU program through NSF Award AST-1004881 to the University of Wisconsin-Madison.

  5. Consistency of cosmic-ray source abudances with explosive nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Kozlovsky, B.; Ramaty, R.

    1973-01-01

    A model was examined in which the cosmic ray abundances of elements from C to Fe are consistent with explosive nucleosynthesis. The observed abundance of cosmic rays near the earth, cosmic ray source abundance, and solar system abundance are discussed along with the ratios of cosmic ray sources to the solar system abundances.

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

    ERIC Educational Resources Information Center

    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…

  7. Elemental advances of ultraheavy cosmic rays

    NASA Technical Reports Server (NTRS)

    1984-01-01

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

  8. Possible cosmic ray signatures in clouds?

    NASA Astrophysics Data System (ADS)

    Erlykin, A. D.; Parsons, R. D.; Wolfendale, A. W.

    2009-11-01

    The role of cosmic rays in cloud formation, by cloud condensation nuclei, is still not fully understood. Although it has been claimed by a number of authors that cosmic ray effects should be small—or even non-existent—it is still argued by others that cosmic ray effects do occur. The present work draws attention to the fact that cosmic rays do not constitute a continuous stream of particles but are characterized by occasional near-simultaneous showers of particles. Under certain circumstances, such showers should leave a signature in clouds—near vertical 'cigar-shaped clouds'—and this work describes their properties. Our own observations have revealed no such structure, but it would be valuable to have a more careful search made.

  9. Space science: Cosmic rays beyond the knees

    NASA Astrophysics Data System (ADS)

    Taylor, Andrew M.

    2016-03-01

    The development of a radio technique for detecting cosmic rays casts fresh light on the origins of some of these accelerated particles, and suggests that they might have travelled much farther than was previously thought. See Letter p.70

  10. Cosmic ray transport near the heliopause

    NASA Astrophysics Data System (ADS)

    Strauss, R. D.; Fichtner, H.; Potgieter, M. S.; le Roux, J. A.; Luo, X.

    2015-09-01

    In this paper we summarize our modelling efforts for cosmic rays near the heliopause, and discuss whether galactic cosmic ray modulation beyond the heliopause is possible and present an explanation for the anisotropic nature of the observed cosmic ray intensities in the very local interstellar medium. We show that (i) modulation beyond the heliopause is possible, but highly dependent on the assumed parameters (most notable, the perpendicular diffusion coefficient). Treating the heliopause as a tangential discontinuity, significantly damps this modulation effect and leads to modelled results that are similar to Voyager 1 observations. (ii) By choosing an appropriate functional form of the perpendicular diffusion coefficient on the pitch-angle level, we are able to account for the anisotropic behaviour observed for both galactic and anomalous cosmic rays in the local interstellar medium.

  11. Relativistic transport theory for cosmic-rays

    NASA Technical Reports Server (NTRS)

    Webb, G. M.

    1985-01-01

    Various aspects of the transport of cosmic-rays in a relativistically moving magnetized plasma supporting a spectrum of hydromagnetic waves that scatter the cosmic-rays are presented. A local Lorentz frame moving with the waves or turbulence scattering the cosmic-rays is used to specify the individual particle momentum. The comoving frame is in general a noninertial frame in which the observer's volume element is expanding and shearing, geometric energy change terms appear in the cosmic-ray transport equation which consist of the relativistic generalization of the adiabatic deceleration term and a further term involving the acceleration vector of the scatterers. A relativistic version of the pitch angle evolution equation, including the effects of adiabatic focussing, pitch angle scattering, and energy changes is presented.

  12. Heliosphere Changes Affect Cosmic Ray Penetration

    NASA Video Gallery

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

  13. IMF Prediction with Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Bieber, J. W.; Evenson, P. A.; Kuwabara, T.; Pei, C.

    2013-12-01

    Cosmic rays impacting Earth have passed through and interacted with the interplanetary magnetic field (IMF) surrounding Earth, and in some sense they carry information on the three-dimensional structure of that field. This work uses neutron monitor data in an effort to extract that information and use it to predict the future behavior of the IMF, especially the north-south component (Bz) which is so crucial in determining geomagnetic activity. We consider 161 events from a published list of interplanetary coronal mass ejections and compare hourly averages of the predicted field with the actual field measured later. We find that the percentage of events with 'good' predictions of Bz (in the sense of having a positive correlation between the prediction and the subsequent measurement) varies from about 85% for predictions 1 hour into the future to about 60% for predictions 4 hours into the future. We present several ideas for how the method might be improved in future implementations. Supported by NASA grant NNX08AQ01G and NSF grant ANT-0739620.

  14. Radar Detection of Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Myers, Isaac

    2012-03-01

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

  15. COSMIC-RAY HELIUM HARDENING

    SciTech Connect

    Ohira, Yutaka; Ioka, Kunihito

    2011-03-01

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

  16. Cosmic Rays and Space Weather

    NASA Astrophysics Data System (ADS)

    Dorman, Lev

    In this review-paper we consider following problems. 1. Cosmic rays (CR) as element of space weather 1.1. Influence of CR on the Earth's atmosphere and global climate change 1.2. Radia-tion hazard from galactic CR 1.3. Radiation hazard from solar CR 1.4. Radiation hazard from energetic particle precipitation from radiation belts 2. CR as tool for space weather forecasting 2.1. Forecasting of the part of global climate change caused by CR intensity variations 2.2. Forecasting of radiation hazard for aircrafts and spacecrafts caused by variations of galactic CR intensity 2.3. Forecasting of the radiation hazard from solar CR events by using on-line one-min ground neutron monitors network and satellite data 2.4. Forecasting of great magnetic storms hazard by using on-line one hour CR intensity data from ground based world-wide network of neutron monitors and muon telescopes 3. CR, space weather, and satellite anomalies 4. CR, space weather, and people health

  17. Source composition of cosmic rays

    SciTech Connect

    Silberberg, R.; Tsao, C.H. ); Shapiro, M.M. )

    1990-03-20

    A theory is developed that yields great improvement in deriving the cosmic-ray source abundances for energies below 10{sup 12} eV/u. In addition, based on the acceleration theory of Voelk and Biermann and on nucleosynthesis processes in pre-supernova stars, a theory is presented for the source composition at 10{sup 12}--10{sup 15} eV/u. The strong shock wave of young supernova remnant accelerates the wind particles of the pre-supernova red, blue supergiant stars and Wolf-Rayet (WR) stars to energies up to 10{sup 15} eV/u. They contain the nucleosynthesis products of the CNO cycle and of He-burning. They accelerate the flare particles in interstellar space. The composition below 10{sup 12} eV/u differs from that of the general stellar photosphere by: (1) Suppression of elements with a large FIP ({gt}10 eV) by a factor of 4; (2) The depletion of light nuclei (Z{le}10); (3) A large contribution of WC stars to {sup 12}C, {sup 16}O and {sup 22}Ne, with renormalization of the initial (Z{gt}2)/(Z{le}2) abundances of Prantzos et al., based on general elemental abundances.

  18. International Cosmic Ray Conference, 13th, University of Denver, Denver, Colo., August 17-30, 1973, Proceedings. Volume 5

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An X-ray observation of the Norma-Lupus region, charge and isotope measurements of heavy cosmic ray nuclei and their role in the determination of cosmic ray age, and the possibility of a contribution to primary cosmic ray spectra from pulsars are among the topics covered in papers concerned with some of the results of recent cosmic ray research. Other topics covered include multiple scattering of charged particles in magnetic fields, absorption of primary cosmic rays in the atmosphere, and phase lag effects on cosmic ray modulation during a recent solar cycle. Individual items are announced in this issue.

  19. Cosmic Ray Interaction Models: an Overview

    NASA Astrophysics Data System (ADS)

    Ostapchenko, Sergey

    2016-07-01

    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.

  20. Cosmic ray test of INO RPC stack

    NASA Astrophysics Data System (ADS)

    Bhuyan, M.; Datar, V. M.; Kalmani, S. D.; Lahamge, S. M.; Mondal, N. K.; Nagaraj, P.; Pal, S.; Reddy, L. V.; Redij, A.; Samuel, D.; Saraf, M. N.; Satyanarayana, B.; Shinde, R. R.; Verma, P.

    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 ×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.

  1. Tevatron QCD for Cosmic-Rays

    SciTech Connect

    Sonnenschein, Lars; /RWTH Aachen U.

    2010-12-01

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

  2. Models of Cosmic-Ray Origin

    NASA Astrophysics Data System (ADS)

    Shapiro, M. M.

    2001-08-01

    Two models of cosmic-ray genesis are compared: (a) the author s red-dwarf hypothesis requiring the injection of seed particles from coronal mass ejections (CME) prior to shock acceleration, and (b) the direct acceleration of thermal ions and of grains in the ISM, proposed by Meyer, Drury and Ellison. Both models agree that shocks in the expanding envelopes of supernova remnants are principally responsible for acceleration to cosmic-ray energies. Both are designed to overcome the mismatch between the source composition of the Galactic cosmic rays (GCR) and the composition of the thermal ISM gas. Model (a) utilizes the prolific emissions of energetic particles from active dMe and dKe stars via their CME as the agents of seed-particle injection into the ISM. The composition of these seed particles is governed by the FIP (first-ionization potential) selection mechanism that operates for both Galactic cosmic rays and solar energetic particles. Hence it is consistent with the cosmic-ray source composition. Model (b) relies on the sputtering and acceleration of grains in the ISM (along with acceleration of thermal ions) to provide the known source composition. This model considers the FIP ordering of GCR abundances as purely coincidental, and it attributes the relative source abundances to selection according to volatility. Recent cosmic-ray observations in favor of each model are cited.

  3. Cosmic ray produced isotopes in terrestrial systems.

    NASA Astrophysics Data System (ADS)

    Lal, D.

    1998-12-01

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

  4. Cosmic-ray backgrounds in infrared bolometers

    NASA Technical Reports Server (NTRS)

    Nolt, I. G.; Radostitz, J. V.; Carlotti, M.; Carli, B.; Mencaraglia, F.

    1985-01-01

    Model calculations for the production of cosmic ray events in IR detectors by energy impulses due to fast charged particles' ionization trails are presently compared to the pulse-amplitude spectrum observed from a balloon at an altitude of 38 km. The results are pertinent to the current understanding of cosmic ray backgrounds found in all high sensitivity bolometer applications. The observed signal transients are in all details consistent with the modeling of known cosmic charged particle flux characteristics and with the detector response. Generally, the optics design should minimize detector/substrate cross section.

  5. Galactic Cosmic Rays: From Earth to Sources

    NASA Technical Reports Server (NTRS)

    Brandt, Theresa J.

    2012-01-01

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

  6. Development of the cosmic ray techniques

    NASA Technical Reports Server (NTRS)

    Rossi, B.

    1982-01-01

    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.

  7. The Contribution of z < or Approx. 6 Sources to the Spatial Coherence in the Unresolved Cosmic Near-Infrared and X-Ray Backgrounds

    NASA Technical Reports Server (NTRS)

    Helgason, K.; Cappelluti, N.; Hasinger, G.; Kashlinsky, A.; Ricotti, M.

    2014-01-01

    A spatial clustering signal has been established in Spitzer/IRAC measurements of the unresolved cosmic near-infrared background (CIB) out to large angular scales, approx. 1deg. This CIB signal, while significantly exceeding the contribution from the remaining known galaxies, was further found to be coherent at a highly statistically significant level with the unresolved soft cosmic X-ray background (CXB). This measurement probes the unresolved CXB to very faint source levels using deep near-IR source subtraction.We study contributions from extragalactic populations at low to intermediate redshifts to the measured positive cross-power signal of the CIB fluctuations with the CXB. We model the X-ray emission from active galactic nuclei (AGNs), normal galaxies, and hot gas residing in virialized structures, calculating their CXB contribution including their spatial coherence with all infrared emitting counterparts. We use a halo model framework to calculate the auto and cross-power spectra of the unresolved fluctuations based on the latest constraints of the halo occupation distribution and the biasing of AGNs, galaxies, and diffuse emission. At small angular scales (1), the 4.5microns versus 0.5-2 keV coherence can be explained by shot noise from galaxies and AGNs. However, at large angular scales (approx.10), we find that the net contribution from the modeled populations is only able to account for approx. 3% of the measured CIB×CXB cross-power. The discrepancy suggests that the CIB×CXB signal originates from the same unknown source population producing the CIB clustering signal out to approx. 1deg.

  8. Spiral arms as cosmic ray source distributions

    NASA Astrophysics Data System (ADS)

    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

  9. Estimates of cellular mutagenesis from cosmic rays

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Wilson, John W.

    1994-01-01

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

  10. Cascaded Gamma Rays as a Probe of Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Murase, Kohta

    2014-06-01

    Very-high-energy (VHE) and ultra-high-energy (UHE) gamma rays from extragalactic sources experience electromagnetic cascades during their propagation in intergalactic space. Recent gamma-ray data on TeV blazars and the diffuse gamma-ray background may have hints of the cascade emission, which are especially interesting if it comes from UHE cosmic rays. I show that cosmic-ray-induced cascades can be discriminated from gamma-ray-induced cascades with detailed gamma-ray spectra. I also discuss roles of structured magnetic fields, which suppress inverse-Compton pair halos/echoes but lead to guaranteed signals - synchrotron pair halos/echoes.