WorldWideScience

Sample records for afterglow

  1. Chameleon induced atomic afterglow

    International Nuclear Information System (INIS)

    Brax, Philippe; Burrage, Clare

    2010-01-01

    The chameleon is a scalar field whose mass depends on the density of its environment. Chameleons are necessarily coupled to matter particles and will excite transitions between atomic energy levels in an analogous manner to photons. When created inside an optical cavity by passing a laser beam through a constant magnetic field, chameleons are trapped between the cavity walls and form a standing wave. This effect will lead to an afterglow phenomenon even when the laser beam and the magnetic field have been turned off, and could be used to probe the interactions of the chameleon field with matter.

  2. Chameleon Induced Atomic Afterglow

    CERN Document Server

    Brax, Philippe

    2010-01-01

    The chameleon is a scalar field whose mass depends on the density of its environment. Chameleons are necessarily coupled to matter particles and will excite transitions between atomic energy levels in an analogous manner to photons. When created inside an optical cavity by passing a laser beam through a constant magnetic field, chameleons are trapped between the cavity walls and form a standing wave. This effect will lead to an afterglow phenomenon even when the laser beam and the magnetic field have been turned off, and could be used to probe the interactions of the chameleon field with matter.

  3. Chameleon induced atomic afterglow

    International Nuclear Information System (INIS)

    Brax, Philippe

    2010-09-01

    The chameleon is a scalar field whose mass depends on the density of its environment. Chameleons are necessarily coupled to matter particles and will excite transitions between atomic energy levels in an analogous manner to photons. When created inside an optical cavity by passing a laser beam through a constant magnetic field, chameleons are trapped between the cavity walls and form a standing wave. This effect will lead to an afterglow phenomenon even when the laser beam and the magnetic field have been turned off, and could be used to probe the interactions of the chameleon field with matter. (orig.)

  4. Chameleon induced atomic afterglow

    Energy Technology Data Exchange (ETDEWEB)

    Brax, Philippe [CEA, IPhT, CNRS, Gif-sur-Yvette (France). Inst. de Physique Theorique; Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-09-15

    The chameleon is a scalar field whose mass depends on the density of its environment. Chameleons are necessarily coupled to matter particles and will excite transitions between atomic energy levels in an analogous manner to photons. When created inside an optical cavity by passing a laser beam through a constant magnetic field, chameleons are trapped between the cavity walls and form a standing wave. This effect will lead to an afterglow phenomenon even when the laser beam and the magnetic field have been turned off, and could be used to probe the interactions of the chameleon field with matter. (orig.)

  5. On the anomalous afterglow seen in a chameleon afterglow search

    International Nuclear Information System (INIS)

    Steffen, Jason H.; Baumbaugh, Alan; Chou, Aaron S.; Tomlin, Ray; Upadhye, Amol

    2012-01-01

    We present data from our investigation of the anomalous orange-colored afterglow that was seen in the GammeV Chameleon Afterglow Search (CHASE). These data include information about the broadband color of the observed glow, the relationship between the glow and the temperature of the apparatus, and other data taken prior to, and during the science operations of CHASE. While differing in several details, the generic properties of the afterglow from CHASE are similar to luminescence seen in some vacuum compounds. Contamination from this, or similar, luminescent signatures will likely impact the design of implementation of future experiments involving single photon detectors and high intensity light sources in a cryogenic environment.

  6. Observations of Early Optical Afterglows

    OpenAIRE

    Roming, Peter W. A.; Mason, Keith O.

    2006-01-01

    The Swift Ultra-Violet/Optical Telescope (UVOT) has performed extensive follow-up on 71 Swift Burst Alert Telescope triggered gamma-ray bursts (GRBs) in its first ten months of operations. In this paper, we discuss some of the UV and optical properties of UVOT detected afterglows such as XRF 050406, the bright GRB 050525A, the high redshift GRB 050730, the early flaring GRB 050801, and others. We also discuss some of the implications of why 75% of GRB afterglows observed by UVOT in less than ...

  7. Investigations on afterglows of neon gas discharges

    International Nuclear Information System (INIS)

    Steenhuysen, L.W.G.

    1979-01-01

    Experimental and numerical investigations on afterglows of neon gas discharges are described. The investigated pressure range extends from 0.5 torr to 100 torr; the discharge currents lie between about 1 mA and 100 mA. The decay of the 1s atom densities has been determined experimentally as function of the time elapsed in the afterglow. From the measured decay of metastable 1s 5 atom densities at gas pressure 5 atoms as well as the coefficinets of atomic collisional transfer between the 1s 5 and 1s 4 level are determined. To obtain more insight in the mutual influences of the various loss and production processes of 1s atoms and charge carriers in the afterglow a numerical model has been formed. The behaviour of the afterglow radiation intensity has been measured on discharges with a gas pressure of 1, 10, 20, 50 and 100 torr and a discharge current of 22, 24 and 50 mA. From the results the recombination distribution fractions of the 1s levels are determined and the electron densities at the start of the afterglow of 20, 50 and 100 torr discharges. With the help of the selective excitation spectroscopy the coefficients of atomic transfer between the 2p levels have been measured in the afterglow of discharge with a gas pressure of 1, 10, 20, 50 and 100 torr and a discharge current of 22 mA. From these results and the measured intensities of the various spectral lines in the afterglow the partial recombination coefficients for the 2p levels are calculated. (Auth. )

  8. Afterglow of chlorophyll in vivo and photosynthesis

    NARCIS (Netherlands)

    Goedheer, J.C.

    1962-01-01

    Two pigment systems are involved in the afterglow of chlorophyll a-containing cells. Absorption in only one of these systems (promoting or “p” system) is effective in producing luminescence. If light is absorbed simultaneously by the other (quenching or “q” system), a decrease in luminescence

  9. Short GRB afterglows observed with GROND

    DEFF Research Database (Denmark)

    Nicuesa Guelbenzu, A.; Klose, S.; Rossi, A.

    2013-01-01

    We report on follow-up observations of 20 short-duration gamma-ray bursts (T90 < 2s) performed in g′r′i′z′JHK s with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the end of 2010. This is the most homogeneous and comprehensive data set on GRB afterglow observatio...

  10. Radio Afterglows of Gamma Ray Bursts

    Indian Academy of Sciences (India)

    Lekshmi Resmi

    2017-09-12

    Sep 12, 2017 ... ments on-board high energy missions like BeppoSAX1,. CGRO2, HETE3, .... rest energy of a solar mass object (GRB 080916C; Abdo et al. 2009). ..... Though the same afterglow physics applies to short bursts too, there are.

  11. Study of argon-oxygen flowing afterglow

    Science.gov (United States)

    Mazánková, V.; Trunec, D.; Navrátil, Z.; Raud, J.; Krčma, F.

    2016-06-01

    The reaction kinetics in argon-oxygen flowing afterglow (post-discharge) was studied using NO titration and optical emission spectroscopy. The flowing DC post-discharge in argon-oxygen mixture was created in a quartz tube at the total gas pressure of 1000 Pa and discharge power of 90 W. The O(3P) atom concentration was determined by NO titration at different places along the flow tube. The optical emission spectra were also measured along the flow tube. Argon spectral lines, oxygen lines at 777 nm and 844.6 nm and atmospheric A-band of {{\\text{O}}2} were identified in the spectra. Rotational temperature of {{\\text{O}}2} was determined from the oxygen atmospheric A-band and also the outer wall temperature of the flow tube was measured by a thermocouple and by an IR thermometer. A zero-dimensional kinetic model for the reactions in the afterglow was developed. This model allows the time dependencies of particle concentrations and of gas temperature to be calculated. The wall recombination probability for O(3P) atoms {γ\\text{O≤ft(\\text{P}\\right)}}=≤ft(1.63+/- 0.06\\right)× {{10}-3} and wall deactivation probability for {{\\text{O}}2} (b {{}1}Σ\\text{g}+ ) molecules {γ{{\\text{O}2}≤ft(\\text{b}\\right)}}=≤ft(1.7+/- 0.1\\right)× {{10}-3} were determined from the fit of model results to experimental data. Sensitivity analysis was applied for the analysis of kinetic model in order to reveal the most important reactions in the model. The calculated gas temperature increases in the afterglow and then decreases at later afterglow times after reaching the maximum. This behavior is in good agreement with the spatial rotational temperature dependence. A similar trend was also observed at outer wall temperature measurement.

  12. Product ion diffusion in flowing afterglows

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, M J; Stock, H M.P. [University Coll. of Wales, Aberystwyth (UK). Dept. of Physics

    1975-11-11

    An analysis of the variation of product ion signals in flowing after-glow experiments is presented. It is shown that under certain conditions the relative variation of a single product ion yields not only the total reaction rate coefficients but also the ambipolar diffusion coefficient of the product ion in the buffer gas. Theory is compared with experiment for a number of ion-molecule and Penning reactions.

  13. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H.J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2011-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

  14. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2010-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

  15. GRB 030329: 3 years of radio afterglow monitoring

    NARCIS (Netherlands)

    van der Horst, A.J.; Kamble, A.; Wijers, R.A.M.J.; Resmi, L.; Bhattacharya, D.; Rol, E.; Strom, R.; Kouveliotou, C.; Oosterloo, T.; Ishwara-Chandra, C.H.

    2007-01-01

    Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a three-year monitoring

  16. Circular polarization in the optical afterglow of GRB 121024A

    NARCIS (Netherlands)

    Wiersema, K.; Covino, S.; Toma, K.; van der Horst, A.J.; Varela, K.; Min, M.; Greiner, J.; Starling, R.L.C.; Tanvir, N.R.; Wijers, R.A.M.J.; Campana, S.; Curran, P.A.; Fan, Y.; Fynbo, J.P.U.; Gorosabel, J.; Gomboc, A.; Götz, D.; Hjorth, J.; Jin, Z.P.; Kobayashi, S.; Kouveliotou, C.; Mundell, C.; O’Brien, P.T.; Pian, E.; Rowlinson, A.; Russell, D.M.; Salvaterra, R.; di Serego Alighieri, S.; Tagliaferri, G.; Vergani, S.D.; Elliott, J.; Fariña, C.; Hartoog, O.E.; Karjalainen, R.; Klose, S.; Knust, F.; Levan, A.J.; Schady, P.; Sudilovsky, V.; Willingale, R.

    2014-01-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the

  17. Circular polarization in the optical afterglow of GRB 121024A

    DEFF Research Database (Denmark)

    Wiersema, K.; Covino, S.; Toma, K.

    2014-01-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of th...

  18. GRB 090902B: AFTERGLOW OBSERVATIONS AND IMPLICATIONS

    International Nuclear Information System (INIS)

    Pandey, S. B.; Akerlof, C.; McKay, T. A.; Swenson, C. A.; Perley, D. A.; Kleiser, I. K. W.; Guidorzi, C.; Wiersema, K.; Malesani, D.; Ashley, M. C. B.; Bersier, D.; Cano, Z.; Kobayashi, S.; Melandri, A.; Mottram, C. J.; Gomboc, A.; Ilyin, I.; Jakobsson, P.; Kouveliotou, C.; Levan, A. J.

    2010-01-01

    The optical-infrared afterglow of the Large Area Telescope (LAT)-detected long-duration burst, GRB 090902B, has been observed by several instruments. The earliest detection by ROTSE-IIIa occurred 80 minutes after detection by the Gamma-ray Burst Monitor instrument on board the Fermi Gamma-Ray Space Telescope, revealing a bright afterglow and a decay slope suggestive of a reverse shock origin. Subsequent optical-IR observations followed the light curve for 6.5 days. The temporal and spectral behavior at optical-infrared frequencies is consistent with synchrotron fireball model predictions; the cooling break lies between optical and XRT frequencies ∼1.9 days after the burst. The inferred electron energy index is p = 1.8 ± 0.2, which would however imply an X-ray decay slope flatter than observed. The XRT and LAT data have similar spectral indices and the observed steeper value of the LAT temporal index is marginally consistent with the predicted temporal decay in the radiative regime of the forward shock model. Absence of a jet break during the first 6 days implies a collimation-corrected γ-ray energy E γ > 2.2 x 10 52 erg, one of the highest ever seen in a long-duration gamma-ray bursts. More events combining GeV photon emission with multiwavelength observations will be required to constrain the nature of the central engine powering these energetic explosions and to explore the correlations between energetic quanta and afterglow emission.

  19. Gamma-Ray Burst Afterglows with ALMA

    Science.gov (United States)

    Urata, Y.; Huang, K.; Takahashi, S.

    2015-12-01

    We present multi-wavelength observations including sub-millimeter follow-ups for two GRB afterglows. The rapid SMA and multi-wavelength observations for GRB120326A revealed their complex emissions as the synchrotron self-inverse Compton radiation from reverse shock. The observations including ALMA for GRB131030A also showed the significant X-ray excess from the standard forward shock synchrotron model. Based on these results, we also discuss further observations for (A) constraining of the mass of progenitor with polarization, (B) the first confirmation of GRB jet collimation, and (C) revealing the origin of optically dark GRBs.

  20. Residual dust charges in discharge afterglow

    International Nuclear Information System (INIS)

    Coueedel, L.; Mikikian, M.; Boufendi, L.; Samarian, A. A.

    2006-01-01

    An on-ground measurement of dust-particle residual charges in the afterglow of a dusty plasma was performed in a rf discharge. An upward thermophoretic force was used to balance the gravitational force. It was found that positively charged, negatively charged, and neutral dust particles coexisted for more than 1 min after the discharge was switched off. The mean residual charge for 200-nm-radius particles was measured. The dust particle mean charge is about -5e at a pressure of 1.2 mbar and about -3e at a pressure of 0.4 mbar

  1. Gamma Ray Bursts-Afterglows and Counterparts

    Science.gov (United States)

    Fishman, Gerald J

    1998-01-01

    Several breakthrough discoveries were made last year of x-ray, optical and radio afterglows and counterparts to gamma-ray bursts, and a redshift has been associated with at least one of these. These discoveries were made possible by the fast, accurate gamma-ray burst locations of the BeppoSAX satellite. It is now generally believed that the burst sources are at cosmological distances and that they represent the most powerful explosions in the Universe. These observations also open new possibilities for the study of early star formation, the physics of extreme conditions and perhaps even cosmology. This session will concentrate on recent x-ray, optical and radio afterglow observations of gamma-ray bursts, associated redshift measurements, and counterpart observations. Several review and theory talks will also be presented, along with a summary of the astrophysical implications of the observations. There will be additional poster contributions on observations of gamma-ray burst source locations at wavelengths other than gamma rays. Posters are also solicited that describe new observational capabilities for rapid follow-up observations of gamma-ray bursts.

  2. TGF Afterglows: A New Radiation Mechanism From Thunderstorms

    Science.gov (United States)

    Rutjes, C.; Diniz, G.; Ferreira, I. S.; Ebert, U.

    2017-10-01

    Thunderstorms are known to create terrestrial gamma ray flashes (TGFs) which are microsecond-long bursts created by runaway of thermal electrons from propagating lightning leaders, as well as gamma ray glows that possibly are created by relativistic runaway electron avalanches (RREA) that can last for minutes or more and are sometimes terminated by a discharge. In this work we predict a new intermediate thunderstorm radiation mechanism, which we call TGF afterglow, as it is caused by the capture of photonuclear neutrons produced by a TGF. TGF afterglows are milliseconds to seconds long; this duration is caused by the thermalization time of the intermediate neutrons. TGF afterglows indicate that the primary TGF has produced photons in the energy range of 10-30 MeV; they are nondirectional in contrast to the primary TGF. Gurevich et al. might have reported TGF afterglows in 2011.

  3. MICROWAVE NOISE MEASUREMENT OF ELECTRON TEMPERATURES IN AFTERGLOW PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Leiby, Jr., C. C.; McBee, W. D.

    1963-10-15

    Transient electron temperatures in afterglow plasmas were determined for He (5 and 10 torr), Ne, and Ne plus or minus 5% Ar (2.4 and 24 torr) by combining measurements of plasma microwave noise power, and plasma reflectivity and absorptivity. Use of a low-noise parametric preamplifier permitted continuous detection during the afterglow of noise power at 5.5 Bc in a 1 Mc bandwidth. Electron temperature decays were a function of pressure and gas but were slower than predicted by electron energy loss mechanisms. The addition of argon altered the electron density decay in the neon afterglow but the electron temperature decay was not appreciably changed. Resonances in detected noise power vs time in the afterglow were observed for two of the three plasma waveguide geometries studied. These resonances correlate with observed resonances in absorptivity and occur over the same range of electron densities for a given geometry independent of gas type and pressure. (auth)

  4. MULTI-WAVELENGTH AFTERGLOWS OF FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Yi, Shuang-Xi; Gao, He; Zhang, Bing

    2014-01-01

    The physical origin of fast radio bursts (FRBs) is unknown. Detecting electromagnetic counterparts to FRBs in other wavelengths is essential to measure their distances and to determine their physical origin. Assuming that at least some of them are of cosmological origin, we calculate their afterglow light curves in multiple wavelengths (X-rays, optical, and radio) by assuming a range of total kinetic energies and redshifts. We focus on forward shock emission, but also consider the possibility that some of the FRBs might have bright reverse shock emission. In general, FRB afterglows are too faint to be detected by current detectors. Only if an FRB has a very low radiative efficiency in radio (hence, a very large kinetic energy), and when it is close enough to observe can its afterglow be detected in the optical and radio bands. We discuss observational strategies for detecting these faint afterglows using future telescopes such as Large Synoptic Survey Telescope and Expanded Very Large Array

  5. The ultra-long GRB 111209A. II. Prompt to afterglow and afterglow properties

    Energy Technology Data Exchange (ETDEWEB)

    Stratta, G. [Osservatorio Astronomico di Roma (OAR/INAF), via Frascati 33, I-00040 Monte Porzio Catone (Italy); Gendre, B.; Boër, M. [ARTEMIS, UMR 7250 (CNRS/OCA/UNS), boulevard de l' Observatoire, BP 4229, F-06304 Nice Cedex (France); Atteia, J. L. [Université de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse (France); Coward, D. M.; Howell, E. [School of Physics, University of Western Australia (UWA), Crawley, WA 6009 (Australia); De Pasquale, M.; Oates, S. [Mullard Space Science Laboratory (MSSL), University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Klotz, A. [IRAP, 14, avenue Edouard Belin, F-31400 Toulouse (France); Piro, L. [Istituto di Astrofisica e Planetologia Spaziali di Roma (IAPS/INAF), via fosso del cavaliere 100, I-00133 Roma (Italy)

    2013-12-10

    The 'ultra-long' gamma-ray burst GRB 111209A at redshift z = 0.677 is the longest GRB ever observed thus far, with a rest frame prompt emission duration of ∼4 hr. In order to explain the burst exceptional longevity, a low-metallicity blue supergiant progenitor was invoked. In this article we further constrain the phenomenology and progenitor properties of this peculiar GRB by performing a multiband temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus WIND, XMM-Newton, and TAROT, as well as from other ground-based optical and radio telescopes. We find some peculiar properties that are possibly connected to the exceptional nature of this burst, namely: (1) an unprecedented large optical delay of 410 ± 50 s between the peak time in gamma-rays and the peak time in the optical of a marked multiwavelength flare; (2) multiwavelength prompt emission spectral modeling requires a certain amount of dust in the circumburst environment. The dust produces a rest frame visual extinction of A{sub V} = 0.3-1.5 mag, and may undergo destruction at late times; and (3) we detect the presence of a hard spectral extra power-law component at the end of the X-ray steep steep decay phase and before the start of the X-ray afterglow, which has never been revealed thus far in past GRBs. The optical afterglow shows more usual properties; it has a flux power-law decay with an index of 1.6 ± 0.1 and a late rebrightening feature observed at ∼1.1 the day after the first Burst Alert Telescope trigger. We discuss our findings in the context of several possible interpretations that have been given thus far of the complex multiband GRB phenomenology and propose a binary channel formation for the blue supergiant progenitor.

  6. The ultra-long GRB 111209A. II. Prompt to afterglow and afterglow properties

    International Nuclear Information System (INIS)

    Stratta, G.; Gendre, B.; Boër, M.; Atteia, J. L.; Coward, D. M.; Howell, E.; De Pasquale, M.; Oates, S.; Klotz, A.; Piro, L.

    2013-01-01

    The 'ultra-long' gamma-ray burst GRB 111209A at redshift z = 0.677 is the longest GRB ever observed thus far, with a rest frame prompt emission duration of ∼4 hr. In order to explain the burst exceptional longevity, a low-metallicity blue supergiant progenitor was invoked. In this article we further constrain the phenomenology and progenitor properties of this peculiar GRB by performing a multiband temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus WIND, XMM-Newton, and TAROT, as well as from other ground-based optical and radio telescopes. We find some peculiar properties that are possibly connected to the exceptional nature of this burst, namely: (1) an unprecedented large optical delay of 410 ± 50 s between the peak time in gamma-rays and the peak time in the optical of a marked multiwavelength flare; (2) multiwavelength prompt emission spectral modeling requires a certain amount of dust in the circumburst environment. The dust produces a rest frame visual extinction of A V = 0.3-1.5 mag, and may undergo destruction at late times; and (3) we detect the presence of a hard spectral extra power-law component at the end of the X-ray steep steep decay phase and before the start of the X-ray afterglow, which has never been revealed thus far in past GRBs. The optical afterglow shows more usual properties; it has a flux power-law decay with an index of 1.6 ± 0.1 and a late rebrightening feature observed at ∼1.1 the day after the first Burst Alert Telescope trigger. We discuss our findings in the context of several possible interpretations that have been given thus far of the complex multiband GRB phenomenology and propose a binary channel formation for the blue supergiant progenitor.

  7. The Ultra-long GRB 111209A. II. Prompt to Afterglow and Afterglow Properties

    Science.gov (United States)

    Stratta, G.; Gendre, B.; Atteia, J. L.; Boër, M.; Coward, D. M.; De Pasquale, M.; Howell, E.; Klotz, A.; Oates, S.; Piro, L.

    2013-12-01

    The "ultra-long" gamma-ray burst GRB 111209A at redshift z = 0.677 is the longest GRB ever observed thus far, with a rest frame prompt emission duration of ~4 hr. In order to explain the burst exceptional longevity, a low-metallicity blue supergiant progenitor was invoked. In this article we further constrain the phenomenology and progenitor properties of this peculiar GRB by performing a multiband temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus WIND, XMM-Newton, and TAROT, as well as from other ground-based optical and radio telescopes. We find some peculiar properties that are possibly connected to the exceptional nature of this burst, namely: (1) an unprecedented large optical delay of 410 ± 50 s between the peak time in gamma-rays and the peak time in the optical of a marked multiwavelength flare; (2) multiwavelength prompt emission spectral modeling requires a certain amount of dust in the circumburst environment. The dust produces a rest frame visual extinction of AV = 0.3-1.5 mag, and may undergo destruction at late times; and (3) we detect the presence of a hard spectral extra power-law component at the end of the X-ray steep steep decay phase and before the start of the X-ray afterglow, which has never been revealed thus far in past GRBs. The optical afterglow shows more usual properties; it has a flux power-law decay with an index of 1.6 ± 0.1 and a late rebrightening feature observed at ~1.1 the day after the first Burst Alert Telescope trigger. We discuss our findings in the context of several possible interpretations that have been given thus far of the complex multiband GRB phenomenology and propose a binary channel formation for the blue supergiant progenitor.

  8. Shock wave interaction with pulsed glow discharge and afterglow plasmas

    International Nuclear Information System (INIS)

    Podder, N.K.; LoCascio, A.C.

    2009-01-01

    Acoustic shock waves are launched by the spark-discharge of a high voltage capacitor in pulsed glow discharge and afterglow plasmas. The glow discharge section of the shock tube is switched on for a period of less than one second at a time, during which a shock wave is launched starting with a large delay between the plasma switch-on and the shock-launch. In the subsequent runs this delay is decremented in equal time intervals up to the plasma switch-on time. A photo acoustic deflection method sensitive to the density gradient of the shock wave is used to study the propagating shock structure and velocity in the igniting plasma. A similar set of measurements are also performed at the plasma switch-off, in which the delay time is incremented in equal time intervals from the plasma switch-off time until the afterglow plasma fully neutralizes itself into the room-temperature gas. Thus, complete time histories of the shock wave propagation in the igniting plasma, as well as in the afterglow plasma, are produced. In the igniting plasma, the changes in the shock-front velocity and dispersion are found to be a strong non-linear function of delay until a saturation point is reached. On the other hand, in the afterglow plasma the trend has been opposite and reversing towards the room temperature values. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas

  9. On the afterglow and progenitor of FRB 150418

    OpenAIRE

    Zhang, Bing

    2016-01-01

    Keane et al. recently detected a fading radio source following FRB 150418, leading to the identification of a putative host galaxy at $z = 0.492 \\pm 0.008$. Assuming that the fading source is the afterglow of FRB 150418, I model the afterglow and constrain the isotropic energy of the explosion to be a few $10^{50}$ erg, comparable to that of a short duration GRB. The outflow may have a jet opening angle of $\\sim 0.22$ rad, so that the beaming-corrected energy is below $10^{49}$ erg. The resul...

  10. Visualisation of Honeypot Data Using Graphviz and Afterglow

    Directory of Open Access Journals (Sweden)

    Craig Valli

    2009-06-01

    Full Text Available This research in progress paper explores the use of Graphviz and Afterglow for the analysis of data emanating from a honeypot system. Honeypot systems gather a wide range of data that is often difficult to readily search for patterns and trends using conventional log file analysis techniques. The data from the honeypots has been statically extracted and processed through Afterglow scripts to produce inputs suitable for use by the DOT graph based tools contained within Graphviz.  This paper explores some of the benefits and drawbacks of currently using this type of approach.

  11. Early optical polarization of a gamma-ray burst afterglow.

    Science.gov (United States)

    Mundell, Carole G; Steele, Iain A; Smith, Robert J; Kobayashi, Shiho; Melandri, Andrea; Guidorzi, Cristiano; Gomboc, Andreja; Mottram, Chris J; Clarke, David; Monfardini, Alessandro; Carter, David; Bersier, David

    2007-03-30

    We report the optical polarization of a gamma-ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma-rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2sigma) upper limit on the percentage of polarization, less than 8%, coincides with the fireball deceleration time at the onset of the afterglow. The combination of the rate of decay of the optical brightness and the low polarization at this critical time constrains standard models of GRB ejecta, ruling out the presence of a large-scale ordered magnetic field in the emitting region.

  12. The many phases of gamma-ray burst afterglows

    NARCIS (Netherlands)

    Leventis, K.

    2013-01-01

    Gamma-ray bursts are the brightest sources in the universe. Their afterglows have been observed for about 15 years now, and their study has greatly advanced our understanding of these, mysterious until recently, events. In a way, gamma-ray bursts can be seen as huge cosmic bombs which convert

  13. DISCOVERY OF RADIO AFTERGLOW FROM THE MOST DISTANT COSMIC EXPLOSION

    International Nuclear Information System (INIS)

    Chandra, Poonam; Frail, Dale A.; Fox, Derek; Kulkarni, Shrinivas; Harrsion, Fiona; Kasliwal, Mansi; Berger, Edo; Cenko, S. Bradley; Bock, Douglas C.-J.

    2010-01-01

    We report on the discovery of radio afterglow emission from the gamma-ray burst GRB 090423, which exploded at a redshift of 8.3, making it the object with the highest known redshift in the universe. By combining our radio measurements with existing X-ray and infrared observations, we estimate the kinetic energy of the afterglow, the geometry of the outflow, and the density of the circumburst medium. Our best-fit model suggests a quasi-spherical, high-energy explosion in a low, constant-density medium. GRB 090423 had a similar energy release to the other well-studied high redshift GRB 050904 (z = 6.26), but their circumburst densities differ by 2 orders of magnitude. We compare the properties of GRB 090423 with a sample of gamma-ray bursts (GRBs) at moderate redshifts. We find that the high energy and afterglow properties of GRB 090423 are not sufficiently different from other GRBs to suggest a different kind of progenitor, such as a Population III (Pop III) star. However, we argue that it is not clear that the afterglow properties alone can provide convincing identification of Pop III progenitors. We suggest that the millimeter and centimeter radio detections of GRB 090423 at early times contained emission from the reverse shock. If true, this may have important implications for the detection of high-redshift GRBs by the next generation of radio facilities.

  14. Atmospheric pressure helium afterglow discharge detector for gas chromatography

    Science.gov (United States)

    Rice, Gary; D'Silva, Arthur P.; Fassel, Velmer A.

    1986-05-06

    An apparatus for providing a simple, low-frequency electrodeless discharge system for atmospheric pressure afterglow generation. A single quartz tube through which a gas mixture is passed is extended beyond a concentric electrode positioned thereabout. A grounding rod is placed directly above the tube outlet to permit optical viewing of the discharge between the electrodes.

  15. Measurements of EEDF in recombination dominated afterglow plasma

    Science.gov (United States)

    Plasil, R.; Korolov, I.; Kotrik, T.; Varju, J.; Dohnal, P.; Donko, Z.; Bano, G.; Glosik, J.

    2009-11-01

    Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and recombination governed plasmas used for studies of recombination of KrD+ and H3+ ions.

  16. Measurements of EEDF in recombination dominated afterglow plasma

    Energy Technology Data Exchange (ETDEWEB)

    Plasil, R; Korolov, I; Kotrik, T; Varju, J; Dohnal, P; Glosik, J [Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Prague (Czech Republic); Donko, Z; Bano, G, E-mail: radek.plasil@mff.cuni.c [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary)

    2009-11-15

    Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and recombination governed plasmas used for studies of recombination of KrD{sup +} and H{sub 3}{sup +} ions.

  17. Measurements of EEDF in recombination dominated afterglow plasma

    International Nuclear Information System (INIS)

    Plasil, R; Korolov, I; Kotrik, T; Varju, J; Dohnal, P; Glosik, J; Donko, Z; Bano, G

    2009-01-01

    Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and recombination governed plasmas used for studies of recombination of KrD + and H 3 + ions.

  18. The Supercritical Pile GRB Model: The Prompt to Afterglow Evolution

    Science.gov (United States)

    Mastichiadis, A.; Kazanas, D.

    2009-01-01

    The "Supercritical Pile" is a very economical GRB model that provides for the efficient conversion of the energy stored in the protons of a Relativistic Blast Wave (RBW) into radiation and at the same time produces - in the prompt GRB phase, even in the absence of any particle acceleration - a spectral peak at energy approx. 1 MeV. We extend this model to include the evolution of the RBW Lorentz factor Gamma and thus follow its spectral and temporal features into the early GRB afterglow stage. One of the novel features of the present treatment is the inclusion of the feedback of the GRB produced radiation on the evolution of Gamma with radius. This feedback and the presence of kinematic and dynamic thresholds in the model can be the sources of rich time evolution which we have began to explore. In particular. one can this may obtain afterglow light curves with steep decays followed by the more conventional flatter afterglow slopes, while at the same time preserving the desirable features of the model, i.e. the well defined relativistic electron source and radiative processes that produce the proper peak in the (nu)F(sub nu), spectra. In this note we present the results of a specific set of parameters of this model with emphasis on the multiwavelength prompt emission and transition to the early afterglow.

  19. GRB 030227: The first multiwavelength afterglow of an INTEGRAL GRB

    DEFF Research Database (Denmark)

    Castro-Tirado, A.J.; Gorosabel, J.; Guziy, S.

    2003-01-01

    We present multiwavelength observations of a gamma-ray burst detected by INTEGRAL (GRB 030227) between 5.3 hours and similar to1.7 days after the event. Here we report the discovery of a dim optical afterglow (OA) that would not have been detected by many previous searches due to its faintess (R ...

  20. The possibilities of CCD photometry of optical afterglows of GRBs

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Polášek, Cyril; Jelínek, M.; Hudec, René; Štrobl, Jan

    -, č. 125 (2010), s. 24-28 ISSN 1801-5964. [Conference on Variable Stars Research /41./. Prague, 27.11.2009-29.11.2009] Institutional research plan: CEZ:AV0Z10030501 Keywords : gamma-ray bursts * optical afterglows * CCD photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  1. Colour variations in the GRB 120327A afterglow

    Czech Academy of Sciences Publication Activity Database

    Melandri, A.; Covino, S.; Zaninoni, E.; Campana, S.; Bolmer, J.; Cobb, B. E.; Gorosabel, J.; Kim, J.W.; Kuindersma, S.; Kuroda, D.; Malesani, D.; Mundell, C. G.; Nappo, F.; Sbarufatti, B.; Smith, R. J.; Steele, I.A.; Topinka, M.; Trotter, G.; Virgili, F. J.; Bernardini, M. G.; D'Avanzo, P.; D'Elia, V.; Fugazza, D.; Ghirlanda, G.; Gomboc, A.; Greiner, J.; Guidorzi, C.; Haislip, J.B.; Hanayama, H.; Hanlon, L.; Im, M.; Ivarsen, K.M.; Japelj, J.; Jelínek, Martin; Kawai, N.; Kobayashi, S.; Kopac, D.; LaCluyze, A.; Martin-Carrillo, A.; Murphy, D.; Reichart, D. E.; Salvaterra, R.; Salafia, O. S.; Tagliaferri, G.; Vergani, S. D.

    2017-01-01

    Roč. 607, October (2017), A29/1-A29/5 E-ISSN 1432-0746 Institutional support: RVO:67985815 Keywords : gamma-ray burst * time-dependent photoionization * early optical afterglow Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

  2. The two-component afterglow of Swift GRB 050802

    Science.gov (United States)

    Oates, S. R.; de Pasquale, M.; Page, M. J.; Blustin, A. J.; Zane, S.; McGowan, K.; Mason, K. O.; Poole, T. S.; Schady, P.; Roming, P. W. A.; Page, K. L.; Falcone, A.; Gehrels, N.

    2007-09-01

    This paper investigates GRB 050802, one of the best examples of a Swift gamma-ray burst afterglow that shows a break in the X-ray light curve, while the optical counterpart decays as a single power law. This burst has an optically bright afterglow of 16.5 mag, detected throughout the 170-650nm spectral range of the Ultraviolet and Optical Telescope (UVOT) onboard Swift. Observations began with the X-ray Telescope and UVOT telescopes 286s after the initial trigger and continued for 1.2 ×106s. The X-ray light curve consists of three power-law segments: a rise until 420s, followed by a slow decay with α =0.63 +/-0.03 until 5000s, after which, the light curve decays faster with a slope of α3 =1.59 +/-0.03. The optical light curve decays as a single power law with αO =0.82 +/-0.03 throughout the observation. The X-ray data on their own are consistent with the break at 5000s being due to the end of energy injection. Modelling the optical to X-ray spectral energy distribution, we find that the optical afterglow cannot be produced by the same component as the X-ray emission at late times, ruling out a single-component afterglow. We therefore considered two-component jet models and find that the X-ray and optical emission is best reproduced by a model in which both components are energy injected for the duration of the observed afterglow and the X-ray break at 5000s is due to a jet break in the narrow component. This bright, well-observed burst is likely a guide for interpreting the surprising finding of Swift that bursts seldom display achromatic jet breaks.

  3. The relation of the colors of the optical afterglow of GRB030329/SN 2003dh to other afterglows

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, René; Pizzichini, G.

    2005-01-01

    Roč. 28, 04-05 (2005), s. 545-548 ISSN 0390-5551. [Gamma-Ray Burst in the Afterglow Era. Roma, 18.10.2004-22.10.2004] R&D Projects: GA AV ČR IAA3003206 Keywords : gamma-ray sources * gamma-ray bursts * supernovae Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  4. Gamma-ray Burst Formation Environment: Comparison of Redshift Distributions of GRB Afterglows

    Directory of Open Access Journals (Sweden)

    Sung-Eun Kim

    2005-12-01

    Full Text Available Since gamma-ray bursts(GRBs have been first known to science societites in 1973, many scientists are involved in their studies. Observations of GRB afterglows provide us with much information on the environment in which the observed GRBs are born. Study of GRB afterglows deals with longer timescale emissions in lower energy bands (e.g., months or even up to years than prompt emissions in gamma-rays. Not all the bursts accompany afterglows in whole ranges of wavelengths. It has been suggested as a reason for that, for instance, that radio and/or X-ray afterglows are not recorded mainly due to lower sensitivity of detectors, and optical afterglows due to extinctions in intergalactic media or self-extinctions within a host galaxy itself. Based on the idea that these facts may also provide information on the GRB environment, we analyze statistical properties of GRB afterglows. We first select samples of the redshift-known GRBs according to the wavelength of afterglow they accompanied. We then compare their distributions as a function of redshift, using statistical methods. As a results, we find that the distribution of the GRBs with X-ray afterglows is consistent with that of the GRBs with optical afterglows. We, therefore, conclude that the lower detection rate of optical afterglows is not due to extinctions in intergalactic media.

  5. Exploring short-GRB afterglow parameter space for observations in coincidence with gravitational waves

    Science.gov (United States)

    Saleem, M.; Resmi, L.; Misra, Kuntal; Pai, Archana; Arun, K. G.

    2018-03-01

    Short duration Gamma Ray Bursts (SGRB) and their afterglows are among the most promising electromagnetic (EM) counterparts of Neutron Star (NS) mergers. The afterglow emission is broad-band, visible across the entire electromagnetic window from γ-ray to radio frequencies. The flux evolution in these frequencies is sensitive to the multidimensional afterglow physical parameter space. Observations of gravitational wave (GW) from BNS mergers in spatial and temporal coincidence with SGRB and associated afterglows can provide valuable constraints on afterglow physics. We run simulations of GW-detected BNS events and assuming that all of them are associated with a GRB jet which also produces an afterglow, investigate how detections or non-detections in X-ray, optical and radio frequencies can be influenced by the parameter space. We narrow down the regions of afterglow parameter space for a uniform top-hat jet model, which would result in different detection scenarios. We list inferences which can be drawn on the physics of GRB afterglows from multimessenger astronomy with coincident GW-EM observations.

  6. The optical afterglow of the short gamma-ray burst GRB 050709.

    Science.gov (United States)

    Hjorth, Jens; Watson, Darach; Fynbo, Johan P U; Price, Paul A; Jensen, Brian L; Jørgensen, Uffe G; Kubas, Daniel; Gorosabel, Javier; Jakobsson, Páll; Sollerman, Jesper; Pedersen, Kristian; Kouveliotou, Chryssa

    2005-10-06

    It has long been known that there are two classes of gamma-ray bursts (GRBs), mainly distinguished by their durations. The breakthrough in our understanding of long-duration GRBs (those lasting more than approximately 2 s), which ultimately linked them with energetic type Ic supernovae, came from the discovery of their long-lived X-ray and optical 'afterglows', when precise and rapid localizations of the sources could finally be obtained. X-ray localizations have recently become available for short (duration burst: GRB 050709. The optical afterglow was localized with subarcsecond accuracy, and lies in the outskirts of a blue dwarf galaxy. The optical and X-ray afterglow properties 34 h after the GRB are reminiscent of the afterglows of long GRBs, which are attributable to synchrotron emission from ultrarelativistic ejecta. We did not, however, detect a supernova, as found in most nearby long GRB afterglows, which suggests a different origin for the short GRBs.

  7. THE LATE PEAKING AFTERGLOW OF GRB 100418A

    International Nuclear Information System (INIS)

    Marshall, F. E.; Holland, S. T.; Sakamoto, T.; Antonelli, L. A.; Burrows, D. N.; Siegel, M. H.; Covino, S.; Fugazza, D.; De Pasquale, M.; Oates, S. R.; Evans, P. A.; O'Brien, P. T.; Osborne, J. P.; Pagani, C.; Liang, E. W.; Wu, X. F.; Zhang, B.

    2011-01-01

    GRB 100418A is a long gamma-ray burst (GRB) at redshift z = 0.6235 discovered with the Swift Gamma-ray Burst Explorer with unusual optical and X-ray light curves. After an initial short-lived, rapid decline in X-rays, the optical and X-ray light curves observed with Swift are approximately flat or rising slightly out to at least ∼7 x 10 3 s after the trigger, peak at ∼5 x 10 4 s, and then follow an approximately power-law decay. Such a long optical plateau and late peaking is rarely seen in GRB afterglows. Observations with Rapid Eye Mount during a gap in the Swift coverage indicate a bright optical flare at ∼2.5 x 10 4 s. The long plateau phase of the afterglow is interpreted using either a model with continuous injection of energy into the forward shock of the burst or a model in which the jet of the burst is viewed off-axis. In both models the isotropic kinetic energy in the late afterglow after the plateau phase is ≥10 2 times the 10 51 erg of the prompt isotropic gamma-ray energy release. The energy injection model is favored because the off-axis jet model would require the intrinsic T 90 for the GRB jet viewed on-axis to be very short, ∼10 ms, and the intrinsic isotropic gamma-ray energy release and the true jet energy to be much higher than the typical values of known short GRBs. The non-detection of a jet break up to t ∼ 2 x 10 6 s indicates a jet half-opening angle of at least ∼14 0 , and a relatively high-collimation-corrected jet energy of E jet ≥ 10 52 erg.

  8. The bright optical afterglow of the long GRB 001007

    DEFF Research Database (Denmark)

    Ceron, J.M.C.; Castro-Tirado, A.J.; Gorosabel, J.

    2002-01-01

    We present optical follow up observations of the long GRB 001007 between 6.14 hours and similar to468 days after the event. An unusually bright optical afterglow (OA) was seen to decline following a steep power law decay with index alpha = -2.03 +/- 0.11, possibly indicating a break in the light...... curve at t - t(0) hours after the gamma ray event provide tentative (1.2σ) evidence for a break in the optical light curve. The spectral index β of the OA yields -1.24 +/- 0.57. These values may be explained both...

  9. Resolving The ISM Surrounding GRBs with Afterglow Spectroscopy

    International Nuclear Information System (INIS)

    Prochaska, J. X.; Chen, H.-W.; Dessauges-Zavadsky, M.; Bloom, J. S.

    2008-01-01

    We review current research related to spectroscopy of gamma-ray burst (GRB) after-glows with particular emphasis on the interstellar medium (ISM) of the galaxies hosting these high redshift events. These studies reveal the physical conditions of star-forming galaxies and yield clues to the nature of the GRB progenitor. We offer a pedagogical review of the experimental design and review current results. The majority of sightlines are characterized by large HI column densities, negligible molecular fraction, the ubiquitous detection of UV pumped fine-structure transitions, and metallicities ranging from 1/100 to nearly solar abundance

  10. Monitoring of the prompt GRB afterglow with the REM telescope

    International Nuclear Information System (INIS)

    Covino, S.; Zerbi, F.; Chincarini, G.; Ghisellini, G.; Conconi, P.; Molinari, E.; Rodono, M.; Cutispoto, G.; Antonelli, L.A.; Nicastro, L.; Palazzi, E.

    2003-01-01

    In these pages we present REM (Rapid Eye Mount), a fully robotized fast slewing telescope equipped with a high throughput NIR (Z', J, H, K) camera and an Optical slitless spectrograph (ROSS) optimized for the monitoring of the prompt afterglow of Gamma Ray Bursts. Covering the NIR domain REM can discover objects at extremely high red-shift and trigger large telescopes to observe them when they are still bright. The synergy between REM-IR cam and ROSS makes REM a powerful observing tool for any kind of fast transient phenomena

  11. Colour variations in the GRB 120327A afterglow

    Science.gov (United States)

    Melandri, A.; Covino, S.; Zaninoni, E.; Campana, S.; Bolmer, J.; Cobb, B. E.; Gorosabel, J.; Kim, J.-W.; Kuin, P.; Kuroda, D.; Malesani, D.; Mundell, C. G.; Nappo, F.; Sbarufatti, B.; Smith, R. J.; Steele, I. A.; Topinka, M.; Trotter, A. S.; Virgili, F. J.; Bernardini, M. G.; D'Avanzo, P.; D'Elia, V.; Fugazza, D.; Ghirlanda, G.; Gomboc, A.; Greiner, J.; Guidorzi, C.; Haislip, J. B.; Hanayama, H.; Hanlon, L.; Im, M.; Ivarsen, K. M.; Japelj, J.; Jelínek, M.; Kawai, N.; Kobayashi, S.; Kopac, D.; LaCluyzé, A. P.; Martin-Carrillo, A.; Murphy, D.; Reichart, D. E.; Salvaterra, R.; Salafia, O. S.; Tagliaferri, G.; Vergani, S. D.

    2017-10-01

    Aims: We present a comprehensive temporal and spectral analysis of the long Swift GRB 120327A afterglow data to investigate possible causes of the observed early-time colour variations. Methods: We collected data from various instruments and telescopes in X-ray, ultraviolet, optical, and near-infrared bands, and determined the shapes of the afterglow early-time light curves. We studied the overall temporal behaviour and the spectral energy distributions from early to late times. Results: The ultraviolet, optical, and near-infrared light curves can be modelled with a single power-law component between 200 and 2 × 104 s after the burst event. The X-ray light curve shows a canonical steep-shallow-steep behaviour that is typical of long gamma-ray bursts. At early times a colour variation is observed in the ultraviolet/optical bands, while at very late times a hint of a re-brightening is visible. The observed early-time colour change can be explained as a variation in the intrinsic optical spectral index, rather than an evolution of the optical extinction. Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A29

  12. On the Afterglow and Progenitor of FRB 150418

    Science.gov (United States)

    Zhang, Bing

    2016-05-01

    Keane et al. recently detected a fading radio source following FRB 150418, leading to the identification of a putative host galaxy at z = 0.492 ± 0.008. Assuming that the fading source is the afterglow of FRB 150418, I model the afterglow and constrain the isotropic energy of the explosion to be a few 1050 erg, comparable to that of a short-duration gamma-ray burst (GRB). The outflow may have a jet opening angle of ˜0.22 rad, so that the beaming-corrected energy is below 1049 erg. The results rule out most fast radio burst (FRB) progenitor models for this FRB, but may be consistent with either of the following two scenarios. The first scenario invokes a merger of an NS-NS binary, which produced an undetected short GRB and a supra-massive neutron star, which subsequently collapsed into a black hole, probably hundreds of seconds after the short GRB. The second scenario invokes a merger of a compact star binary (BH-BH, NS-NS, or BH-NS) system whose pre-merger dynamical magnetospheric activities made the FRB, which is followed by an undetected short GRB-like transient. The gravitational-wave (GW) event GW 150914 would be a sister of FRB 150418 in this second scenario. In both cases, one expects an exciting prospect of GW/FRB/GRB associations.

  13. ON THE AFTERGLOW AND PROGENITOR OF FRB 150418

    International Nuclear Information System (INIS)

    Zhang, Bing

    2016-01-01

    Keane et al. recently detected a fading radio source following FRB 150418, leading to the identification of a putative host galaxy at z = 0.492 ± 0.008. Assuming that the fading source is the afterglow of FRB 150418, I model the afterglow and constrain the isotropic energy of the explosion to be a few 10 50 erg, comparable to that of a short-duration gamma-ray burst (GRB). The outflow may have a jet opening angle of ∼0.22 rad, so that the beaming-corrected energy is below 10 49 erg. The results rule out most fast radio burst (FRB) progenitor models for this FRB, but may be consistent with either of the following two scenarios. The first scenario invokes a merger of an NS–NS binary, which produced an undetected short GRB and a supra-massive neutron star, which subsequently collapsed into a black hole, probably hundreds of seconds after the short GRB. The second scenario invokes a merger of a compact star binary (BH–BH, NS–NS, or BH–NS) system whose pre-merger dynamical magnetospheric activities made the FRB, which is followed by an undetected short GRB-like transient. The gravitational-wave (GW) event GW 150914 would be a sister of FRB 150418 in this second scenario. In both cases, one expects an exciting prospect of GW/FRB/GRB associations.

  14. Fermi and Swift Gamma-Ray Burst Afterglow Population Studies

    Science.gov (United States)

    Racusin, Judith L.; Oates, S. R.; Schady, P.; Burrows, D. N.; dePasquale, M.; Donato, D.; Gehrels, N.; Koch, S.; McEnery, J.; Piran, T.; hide

    2011-01-01

    The new and extreme population of GRBs detected by Fermi -LAT shows several new features in high energy gamma-rays that are providing interesting and unexpected clues into GRB prompt and afterglow emission mechanisms. Over the last 6 years, it has been Swift that has provided the robust dataset of UV/optical and X-ray afterglow observations that opened many windows into components of GRB emission structure. The relationship between the LAT detected GRBs and the well studied, fainter, less energetic GRBs detected by Swift -BAT is only beginning to be explored by multi-wavelength studies. We explore the large sample of GRBs detected by BAT only, BAT and Fermi -GBM, and GBM and LAT, focusing on these samples separately in order to search for statistically significant differences between the populations, using only those GRBs with measured redshifts in order to physically characterize these objects. We disentangle which differences are instrumental selection effects versus intrinsic properties, in order to better understand the nature of the special characteristics of the LAT bursts.

  15. The hidden X-ray breaks in afterglow light curves

    International Nuclear Information System (INIS)

    Curran, P. A.; Wijers, R. A. M. J.; Horst, A. J. van der; Starling, R. L. C.

    2008-01-01

    Gamma-Ray Burst (GRB) afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared to the BeppoSAX, or pre-Swift era. Specifically, relatively few breaks, consistent with jet breaks, are observed in the X-ray light curves of these bursts. If these breaks are truly missing, it has serious consequences for the interpretation of GRB jet collimation and energy requirements, and the use of GRBs as standard candles.Here we address the issue of X-ray breaks which are possibly 'hidden' and hence the light curves are misinterpreted as being single power-laws. We show how a number of precedents, including GRB 990510 and GRB 060206, exist for such hidden breaks and how, even with the well sampled light curves of the Swift era, these breaks may be left misidentified. We do so by synthesising X-ray light curves and finding general trends via Monte Carlo analysis. Furthermore, in light of these simulations, we discuss how to best identify achromatic breaks in afterglow light curves via multi-wavelength analysis

  16. ON THE AFTERGLOW AND PROGENITOR OF FRB 150418

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States)

    2016-05-01

    Keane et al. recently detected a fading radio source following FRB 150418, leading to the identification of a putative host galaxy at z = 0.492 ± 0.008. Assuming that the fading source is the afterglow of FRB 150418, I model the afterglow and constrain the isotropic energy of the explosion to be a few 10{sup 50} erg, comparable to that of a short-duration gamma-ray burst (GRB). The outflow may have a jet opening angle of ∼0.22 rad, so that the beaming-corrected energy is below 10{sup 49} erg. The results rule out most fast radio burst (FRB) progenitor models for this FRB, but may be consistent with either of the following two scenarios. The first scenario invokes a merger of an NS–NS binary, which produced an undetected short GRB and a supra-massive neutron star, which subsequently collapsed into a black hole, probably hundreds of seconds after the short GRB. The second scenario invokes a merger of a compact star binary (BH–BH, NS–NS, or BH–NS) system whose pre-merger dynamical magnetospheric activities made the FRB, which is followed by an undetected short GRB-like transient. The gravitational-wave (GW) event GW 150914 would be a sister of FRB 150418 in this second scenario. In both cases, one expects an exciting prospect of GW/FRB/GRB associations.

  17. Thermal Electrons in Gamma-Ray Burst Afterglows

    Energy Technology Data Exchange (ETDEWEB)

    Ressler, Sean M.; Laskar, Tanmoy [Department of Astronomy, University of California, 501 Campbell Hall, Berkeley, CA 94720-3411 (United States)

    2017-08-20

    To date, nearly all multi-wavelength modeling of long-duration γ -ray bursts has ignored synchrotron radiation from the significant population of electrons expected to pass the shock without acceleration into a power-law distribution. We investigate the effect of including the contribution of thermal, non-accelerated electrons to synchrotron absorption and emission in the standard afterglow model, and show that these thermal electrons provide an additional source of opacity to synchrotron self-absorption, and yield an additional emission component at higher energies. The extra opacity results in an increase in the synchrotron self-absorption frequency by factors of 10–100 for fiducial parameters. The nature of the additional emission depends on the details of the thermal population, but is generally observed to yield a spectral peak in the optical brighter than radiation from the nonthermal population by similar factors a few seconds after the burst, remaining detectable at millimeter and radio frequencies several days later.

  18. InN grown by migration enhanced afterglow (MEAglow)

    International Nuclear Information System (INIS)

    Butcher, Kenneth Scott A.; Alexandrov, Dimiter; Terziyska, Penka; Georgiev, Vasil; Georgieva, Dimka; Binsted, Peter W.

    2012-01-01

    InN thin films were grown by a new technique, migration enhanced afterglow (MEAglow), a chemical vapour deposition (CVD) form of migration enhanced epitaxy (MEE). Here we describe the apparatus used for this form of film deposition, which includes a scalable hollow cathode nitrogen plasma source. Initial film growth results for InN are also presented including atomic force microscopy (AFM) images that indicate step flow growth with samples having root mean square (RMS) surface roughness of as little as 0.103 nm in some circumstances for film growth on sapphire substrates. X-ray diffraction (XRD) results are also provided for samples with a full width half maximum (FWHM) of the (0002) ω-2θ peak of as little as 290 arcsec. Low pressure conditions that can result in damage to the InN during growth are described. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. ELECTRON ENERGY DECAY IN HELIUM AFTERGLOW PLASMAS AT CRYOGENIC TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Goldan, P. D.; Cahn, J. H.; Goldstein, L.

    1963-10-15

    Studies of decaying afterglow plasmas in helium were ined near 4 deg K by immersion in a liquid helium bath. By means of a Maser Radiometer System, the electron temperature was followed below 200 deg K. Guided microwave propagation and wave interaction techniques premit determination of election number density and collision frequencies for momentum transfer. Electron temperature decay rates of the order of 150 mu sec/p(mm Hg alpha 4.2 deg K) were found. Since thermal relaxation by elastic collisions should be some two orders of magnitude faster than this, the electrons appear to be in quasiequilibrium with a slowly decaying internal heating source. Correlation of the expected decay rates of singlet metastable helium atoms with the electron temperature decay gives good agreement with the present experiment. (auth)

  20. Hidden in the light: Magnetically induced afterglow from trapped chameleon fields

    International Nuclear Information System (INIS)

    Gies, Holger; Mota, David F.; Shaw, Douglas J.

    2008-01-01

    We propose an afterglow phenomenon as a unique trace of chameleon fields in optical experiments. The vacuum interaction of a laser pulse with a magnetic field can lead to a production and subsequent trapping of chameleons in the vacuum chamber, owing to their mass dependence on the ambient matter density. Magnetically induced reconversion of the trapped chameleons into photons creates an afterglow over macroscopic timescales that can conveniently be searched for by current optical experiments. We show that the chameleon parameter range accessible to available laboratory technology is comparable to scales familiar from astrophysical stellar energy-loss arguments. We analyze quantitatively the afterglow properties for various experimental scenarios and discuss the role of potential background and systematic effects. We conclude that afterglow searches represent an ideal tool to aim at the production and detection of cosmologically relevant scalar fields in the laboratory

  1. Constraining chameleon field theories using the GammeV afterglow experiments

    International Nuclear Information System (INIS)

    Upadhye, A.; Steffen, J. H.; Weltman, A.

    2010-01-01

    The GammeV experiment has constrained the couplings of chameleon scalar fields to matter and photons. Here, we present a detailed calculation of the chameleon afterglow rate underlying these constraints. The dependence of GammeV constraints on various assumptions in the calculation is studied. We discuss the GammeV-CHameleon Afterglow SEarch, a second-generation GammeV experiment, which will improve upon GammeV in several major ways. Using our calculation of the chameleon afterglow rate, we forecast model-independent constraints achievable by GammeV-CHameleon Afterglow SEarch. We then apply these constraints to a variety of chameleon models, including quartic chameleons and chameleon dark energy models. The new experiment will be able to probe a large region of parameter space that is beyond the reach of current tests, such as fifth force searches, constraints on the dimming of distant astrophysical objects, and bounds on the variation of the fine structure constant.

  2. Searches for hard X-ray gamma-ray burst afterglows with the BAT on Swift

    International Nuclear Information System (INIS)

    Krimm, Hans A.; Ozawa, Hideki; Weidenspointner, Georg; Barbier, Louis M.; Barthelmy, Scott D.; Gehrels, Neil; Parsons, Ann M.; Tueller, Jack; Eftekharzadeh, Ardeshir; Hullinger, Derek D.; Markwardt, Craig; Fenimore, Edward E.; Palmer, David M.

    2003-01-01

    The Burst Alert Telescope (BAT) on the Swift gamma ray burst mission will continue to observe the fields of all detected gamma-ray bursts for several days after the prompt emission has faded. Utilizing first event-by-event data, then one minute and later five minute survey accumulations, the BAT will be extremely sensitive to the hard X-ray afterglow known to be associated with many bursts. This data will cover the crucial transition of the afterglow from rapid variability to the smoothly decaying power law in time and will extend observations of the tails of individual bursts to longer time scales than have been achievable so far. Since Swift is sensitive to short duration GRBs, we will also be able to determine whether hard X-ray afterglows are associated with short GRBs. The BAT will provide high resolution spectra of burst afterglows, allowing us to study in detail the time evolution of GRB spectra

  3. A Study of Electron Decay in Nitrogen Time After-glow

    International Nuclear Information System (INIS)

    Veis, P.; Coitout, H.; Magne, L.; Cernogora, G.

    1999-01-01

    This paper deals with electron density measurements in nitrogen time after-glow using hyper frequency resonant cavity. The studied pressures are from the range 9-530 Pa and discharge currents from 20 mA up to 500 mA. Electrons decreases up to the time of 1,4 ms in after-glow depending on pressure, pulse current and pulse duration (Authors)

  4. Escherichia coli morphological changes and lipid A removal induced by reduced pressure nitrogen afterglow exposure.

    Directory of Open Access Journals (Sweden)

    Hayat Zerrouki

    Full Text Available Lipid A is a major hydrophobic component of lipopolysaccharides (endotoxin present in the membrane of most Gram-negative bacteria, and the major responsible for the bioactivity and toxicity of the endotoxin. Previous studies have demonstrated that the late afterglow region of flowing post-discharges at reduced pressure (1-20 Torr can be used for the sterilization of surfaces and of the reusable medical instrumentation. In the present paper, we show that the antibacterial activity of a pure nitrogen afterglow can essentially be attributed to the large concentrations of nitrogen atoms present in the treatment area and not to the UV radiation of the afterglow. In parallel, the time variation of the inactivation efficiency quantified by the log reduction of the initial Escherichia coli (E. coli population is correlated with morphologic changes observed on the bacteria by scanning electron microscopy (SEM for increasing afterglow exposure times. The effect of the afterglow exposure is also studied on pure lipid A and on lipid A extracted from exposed E. coli bacteria. We report that more than 60% of lipid A (pure or bacteria-extracted are lost with the used operating conditions (nitrogen flow QN2 = 1 standard liter per minute (slpm, pressure p = 5 Torr, microwave injected power PMW = 200 W, exposure time: 40 minutes. The afterglow exposure also results in a reduction of the lipid A proinflammatory activity, assessed by the net decrease of the redox-sensitive NFκB transcription factor nuclear translocation in murine aortic endothelial cells stimulated with control vs afterglow-treated (pure and extracted lipid A. Altogether these results point out the ability of reduced pressure nitrogen afterglows to neutralize the cytotoxic components in Gram-negative bacteria.

  5. Five Years of Multi-frequency Monitoring of GRB030329 Afterglow Using the GMRT and WSRT

    International Nuclear Information System (INIS)

    Kamble, Atish; Wijers, Ralph; Rol, Evert; Horst, A. J. van der; Kouveliotou, Chryssa; Bhattacharya, D.; Chandra, C. H. Ishwara; Resmi, L.; Strom, R.

    2009-01-01

    GRB 030329 displayed one of the brightest optical afterglows ever. We have followed the radio afterglow of GRB 030329 for over 5 years using the GMRT and WSRT at low radio frequencies. This is the longest as well as the lowest frequency follow up of any GRB afterglow ever.Radio observations of a GRB afterglow provide a unique probe of the physics of the blast wave at late times, when the expansion of the fireball slows down to non-relativistic speeds. Our GMRT-WSRT observations suggest that the afterglow of GRB030329 entered the non-relativistic phase around 60 days after the burst. The estimate of the fireball energy content, ∼10 51 erg, in this near-isotropic phase is much less susceptible to the collimation-related uncertainties arising in the relativistic phase. We have also been closely monitoring the evolution of the afterglow to look for possible signatures of emission from a counter jet, but no conclusive evidence has so far been found.

  6. The VLT/X-shooter GRB afterglow legacy survey

    Science.gov (United States)

    Kaper, Lex; Fynbo, Johan P. U.; Pugliese, Vanna; van Rest, Daan

    2017-11-01

    The Swift satellite allows us to use gamma-ray bursts (GRBs) to peer through the hearts of star forming galaxies through cosmic time. Our open collaboration, representing most of the active European researchers in this field, builds a public legacy sample of GRB X-shooter spectroscopy while Swift continues to fly. To date, our spectroscopy of more than 100 GRB afterglows covers a redshift range from 0.059 to about 8 (Tanvir et al. 2009, Nature 461, 1254), with more than 20 robust afterglow-based metallicity measurements (over a redshift range from 1.7 to 5.9). With afterglow spectroscopy (throughout the electromagnetic spectrum from X-rays to the sub-mm) we can hence characterize the properties of star-forming galaxies over cosmic history in terms of redshift, metallicity, molecular content, ISM temperature, UV-flux density, etc.. These observations provide key information on the final evolution of the most massive stars collapsing into black holes, with the potential of probing the epoch of the formation of the first (very massive) stars. VLT/X-shooter (Vernet et al. 2011, A&A 536, A105) is in many ways the ideal GRB follow-up instrument and indeed GRB follow-up was one of the primary science cases behind the instrument design and implementation. Due to the wide wavelength coverage of X-shooter, in the same observation one can detect molecular H2 absorption near the atmospheric cut-off and many strong emission lines from the host galaxy in the near-infrared (e.g., Friis et al. 2015, MNRAS 451, 167). For example, we have measured a metallicity of 0.1 Z ⊙ for GRB 100219A at z = 4.67 (Thöne et al. 2013, MNRAS 428, 3590), 0.02 Z ⊙ for GRB 111008A at z = 4.99 (Sparre et al. 2014, ApJ 785, 150) and 0.05 Z ⊙ for GRB 130606A at z = 5.91 (Hartoog et al. 2015, A&A 580, 139). In the latter, the very high value of [Al/Fe]=2.40 +/- 0.78 might be due to a proton capture process and may be a signature of a previous generation of massive (perhaps even the first) stars

  7. DIVERSITY OF SHORT GAMMA-RAY BURST AFTERGLOWS FROM COMPACT BINARY MERGERS HOSTING PULSARS

    International Nuclear Information System (INIS)

    Holcomb, Cole; Ramirez-Ruiz, Enrico; De Colle, Fabio; Montes, Gabriela

    2014-01-01

    Short-duration gamma-ray bursts (sGRBs) are widely believed to result from the mergers of compact binaries. This model predicts an afterglow that bears the characteristic signatures of a constant, low-density medium, including a smooth prompt-afterglow transition, and a simple temporal evolution. However, these expectations are in conflict with observations for a non-negligible fraction of sGRB afterglows. In particular, the onset of the afterglow phase for some of these events appears to be delayed and, in addition, a few of them exhibit late-time rapid fading in their light curves. We show that these peculiar observations can be explained independently of ongoing central engine activity if some sGRB progenitors are compact binaries hosting at least one pulsar. The Poynting flux emanating from the pulsar companion can excavate a bow-shock cavity surrounding the binary. If this cavity is larger than the shock deceleration length scale in the undisturbed interstellar medium, then the onset of the afterglow will be delayed. Should the deceleration occur entirely within the swept-up thin shell, a rapid fade in the light curve will ensue. We identify two types of pulsar that can achieve the conditions necessary for altering the afterglow: low-field, long-lived pulsars, and high-field pulsars. We find that a sizable fraction (≈20%-50%) of low-field pulsars are likely to reside in neutron star binaries based on observations, while their high-field counterparts are not. Hydrodynamical calculations motivated by this model are shown to be in good agreement with observations of sGRB afterglow light curves

  8. Long afterglow property of Er"3"+ doped Ca_2SnO_4 phosphor

    International Nuclear Information System (INIS)

    Zhang, Dongyun; Shi, Mingming; Sun, Yiwen; Guo, Yunyun; Chang, Chengkang

    2016-01-01

    A novel green emitting long afterglow phosphor, Er"3"+ -doped Ca_2SnO_4 (Ca_2SnO_4:Er"3"+), was prepared successfully via a traditional high temperature solid–state reaction method. Its properties have been characterized and analyzed by utilizing x-ray diffraction (XRD), photoluminescence spectroscope (PLS), afterglow decay curve (ADC) and thermal luminescence spectroscope (TLS). Three main emission peaks of PLS locate at 524, 550 and 668 nm, corresponding to CIE chromaticity coordinates of x = 0.326, y = 0.6592. An optimal doping concentration of Er"3"+ of 2% was determined. The Ca_2SnO_4:Er"3"+ phosphors showed a typical triple-exponential afterglow decay behavior when the UV source was switched off. Thermal simulated luminescence study indicated that the persistent afterglow of Ca_2SnO_4:2 mol% Er"3"+ phosphors was generated by the suitable electron or hole traps which were resulted from the doping the Ca_2SnO_4 host with rare-earth ions (Er"3"+). - Highlights: • A novel green emitting long afterglow phosphor, Ca_2SnO_4:Er"3"+, was prepared. • An optimal doping concentration of Er"3"+ of 2% was determined. • After the UV source was turned off, the Ca_2SnO_4:Er"3"+ showed a typical triple-exponential afterglow decay behavior. • CIE chromaticity coordinates results confirmed a green light emitting of the Ca_2SnO_4:Er"3"+. • The persistent afterglow of the Ca_2SnO_4:Er"3"+ was attributed to suitable electron or hole traps.

  9. Short Hard Gamma Ray Bursts And Their Afterglows

    CERN Document Server

    Dado, Shlomo

    2009-01-01

    Long duration gamma ray bursts (GRBs) and X-ray flashes (XRFs) are produced by highly- relativistic jets ejected in core-collapse supernova explosions. The origin of short hard gamma-ray bursts (SHBs) has not been established. They may be produced by highly relativistic jets ejected in various processes: mergers of compact stellar objects; large-mass accretion episodes onto compact stars in close binaries or onto intermediate-mass black holes in dense stellar regions; phase transition of compact stars. Natural environments of such events are the dense cores of globular clusters, superstar clusters and young supernova remnants. We have used the cannonball model of GRBs to analyze all Swift SHBs with a well-sampled X-ray afterglow. We show that their prompt gamma-ray emission can be explained by inverse Compton scattering (ICS) of the progenitor's glory light, and their extended soft emission component by ICS of high density light or synchrotron radiation (SR) in a high density interstellar medium within the cl...

  10. Impulsive and Varying Injection in Gamma-Ray Burst Afterglows.

    Science.gov (United States)

    Sari; Mészáros

    2000-05-20

    The standard model of gamma-ray burst afterglows is based on synchrotron radiation from a blast wave produced when the relativistic ejecta encounters the surrounding medium. We reanalyze the refreshed shock scenario, in which slower material catches up with the decelerating ejecta and reenergizes it. This energization can be done either continuously or in discrete episodes. We show that such a scenario has two important implications. First, there is an additional component coming from the reverse shock that goes into the energizing ejecta. This persists for as long as the reenergization itself, which could extend for up to days or longer. We find that during this time the overall spectral peak is found at the characteristic frequency of the reverse shock. Second, if the injection is continuous, the dynamics will be different from that in constant energy evolution and will cause a slower decline of the observed fluxes. A simple test of the continuously refreshed scenario is that it predicts a spectral maximum in the far-infrared or millimeter range after a few days.

  11. MODELING EXTRAGALACTIC EXTINCTION THROUGH GAMMA-RAY BURST AFTERGLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Zonca, Alberto; Mulas, Giacomo; Casu, Silvia; Aresu, Giambattista [INAF—Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Cecchi-Pestellini, Cesare, E-mail: azonca@oa-cagliari.inaf.it, E-mail: gmulas@oa-cagliari.inaf.it, E-mail: silvia@oa-cagliari.inaf.it, E-mail: garesu@oa-cagliari.inaf.it, E-mail: cecchi-pestellini@astropa.inaf.it [INAF—Osservatorio Astronomico di Palermo, P.za Parlamento 1, I-90134 Palermo (Italy)

    2016-09-20

    We analyze extragalactic extinction profiles derived through gamma-ray burst afterglows, using a dust model specifically constructed on the assumption that dust grains are not immutable but respond, time-dependently, to the local physics. Such a model includes core-mantle spherical particles of mixed chemical composition (silicate core, sp{sup 2}, and sp{sup 3} carbonaceous layers), and an additional molecular component in the form of free-flying polycyclic aromatic hydrocarbons. We fit most of the observed extinction profiles. Failures occur for lines of sight, presenting remarkable rises blueward of the bump. We find a tendency for the carbon chemical structure to become more aliphatic with the galactic activity, and to some extent with increasing redshifts. Moreover, the contribution of the molecular component to the total extinction is more important in younger objects. The results of the fitting procedure (either successes and failures) may be naturally interpreted through an evolutionary prescription based on the carbon cycle in the interstellar medium of galaxies.

  12. Reddish orange long afterglow phosphor Ca2SnO4:Sm3+prepared by sol-gel method

    International Nuclear Information System (INIS)

    Ju Zhenghua; Zhang Shuihe; Gao Xiuping; Tang Xiaoliang; Liu Weisheng

    2011-01-01

    Highlights: → A promising reddish orange emissive long afterglow phosphor Ca 2 SnO 4 :Sm 3+ prepared by sol-gel method was firstly reported. → The optics properties of Ca 2 SnO 4 :Sm 3+ were discussed. → Very useful tool, thermoluminscent technique was chosen to investigate the traps in the material. The results of thermoluminscent spectra indicating that the depth and number of traps are critical factors in determining their performance. → Furthermore, the phosphorescence mechanism was discussed successfully. → This work provides a potential approach to develop reddish orange light emitting long afterglow phosphor. - Abstract: A reddish orange light emissive long afterglow phosphor, Ca 2 SnO 4 :Sm 3+ was prepared by sol-gel method at lower temperature. The synthesized phosphors were characterized by X-ray diffraction, scanning electron micrograph images, photoluminescence spectra, afterglow decay curves and thermoluminescence spectra. Three emission peaks locate at 565 nm, 609 nm and 655 nm corresponding to CIE chromaticity coordinates of x = 0.53 and y = 0.47, which indicates the reddish orange light emitting. The fluorescent intensity and the afterglow characteristic depends on the concentration of Sm 3+ and the optimized concentration is 1.5 mol%. The afterglow decay curves are well fitted with triple-exponential decay models. The thermoluminescence glow curves show that the Sm 3+ induces suitable trap depth and result in the long afterglow phenomenon, and the corresponding increase or decrease in afterglow is associated with trap concentration, nearly no change in trap depth. The 1.5 mol% Sm 3+ -doped Ca 2 SnO 4 sample has the biggest trap concentration and exhibit the best afterglow characteristic, its' afterglow time is about 1 h. The phosphorescence mechanism of this long afterglow phosphor was discussed.

  13. Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts.

    Science.gov (United States)

    Vestrand, W T; Wren, J A; Wozniak, P R; Aptekar, R; Golentskii, S; Pal'shin, V; Sakamoto, T; White, R R; Evans, S; Casperson, D; Fenimore, E

    2006-07-13

    The taxonomy of optical emission detected during the critical first few minutes after the onset of a gamma-ray burst (GRB) defines two broad classes: prompt optical emission correlated with prompt gamma-ray emission, and early optical afterglow emission uncorrelated with the gamma-ray emission. The standard theoretical interpretation attributes prompt emission to internal shocks in the ultra-relativistic outflow generated by the internal engine; early afterglow emission is attributed to shocks generated by interaction with the surrounding medium. Here we report on observations of a bright GRB that, for the first time, clearly show the temporal relationship and relative strength of the two optical components. The observations indicate that early afterglow emission can be understood as reverberation of the energy input measured by prompt emission. Measurements of the early afterglow reverberations therefore probe the structure of the environment around the burst, whereas the subsequent response to late-time impulsive energy releases reveals how earlier flaring episodes have altered the jet and environment parameters. Many GRBs are generated by the death of massive stars that were born and died before the Universe was ten per cent of its current age, so GRB afterglow reverberations provide clues about the environments around some of the first stars.

  14. MODELING THE AFTERGLOW OF THE POSSIBLE FERMI -GBM EVENT ASSOCIATED WITH GW150914

    Energy Technology Data Exchange (ETDEWEB)

    Morsony, Brian J. [Department of Astronomy, University of Maryland, 1113 Physical Sciences Complex, College Park, MD 20742-2421 (United States); Workman, Jared C. [Department of Physical and Environmental Sciences, Colorado Mesa University, Grand Junction, CO 81501 (United States); Ryan, Dominic M., E-mail: morsony@astro.umd.edu [Department of Astronomy, University of California, Berkeley, 501 Campbell Hall #3411, Berkeley, CA 94720-3411 (United States)

    2016-07-10

    We model the possible afterglow of the Fermi Gamma-ray Burst Monitor (GBM) event associated with LIGO detection GW150914, under the assumption that the gamma-rays are produced by a short GRB-like relativistic outflow. We model GW150914-GBM as both a weak, on-axis short GRB and normal short GRB seen far off-axis. Given the large uncertainty in the position of GW150914, we determine that the best chance of finding the afterglow is with ASKAP or possibly the Murchinson Widefield Array (MWA), with the flux from an off-axis short GRB reaching 0.2–4 mJy (0.12–16 mJy) at 150 MHz (863.5 MHz) by 1–12 months after the initial event. At low frequencies, the source would evolve from a hard to soft spectrum over several months. The radio afterglow would be detectable for several months to years after it peaks, meaning the afterglow may still be detectable and increasing in brightness NOW (2016 mid-July). With a localization from the MWA or ASKAP, the afterglow would be detectable at higher radio frequencies with the ATCA and in X-rays with Chandra or XMM .

  15. MODELING THE AFTERGLOW OF THE POSSIBLE FERMI -GBM EVENT ASSOCIATED WITH GW150914

    International Nuclear Information System (INIS)

    Morsony, Brian J.; Workman, Jared C.; Ryan, Dominic M.

    2016-01-01

    We model the possible afterglow of the Fermi Gamma-ray Burst Monitor (GBM) event associated with LIGO detection GW150914, under the assumption that the gamma-rays are produced by a short GRB-like relativistic outflow. We model GW150914-GBM as both a weak, on-axis short GRB and normal short GRB seen far off-axis. Given the large uncertainty in the position of GW150914, we determine that the best chance of finding the afterglow is with ASKAP or possibly the Murchinson Widefield Array (MWA), with the flux from an off-axis short GRB reaching 0.2–4 mJy (0.12–16 mJy) at 150 MHz (863.5 MHz) by 1–12 months after the initial event. At low frequencies, the source would evolve from a hard to soft spectrum over several months. The radio afterglow would be detectable for several months to years after it peaks, meaning the afterglow may still be detectable and increasing in brightness NOW (2016 mid-July). With a localization from the MWA or ASKAP, the afterglow would be detectable at higher radio frequencies with the ATCA and in X-rays with Chandra or XMM .

  16. Evaluation of scintillator afterglow for use in a combined optical and PET imaging tomograph

    Energy Technology Data Exchange (ETDEWEB)

    Douraghy, Ali [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States)]. E-mail: adouraghy@mednet.ucla.edu; Prout, David L. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States); Silverman, Robert W. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States); Chatziioannou, Arion F. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States)

    2006-12-20

    The design of a dual modality imaging system for small animal optical and positron emission tomography imaging (OPET) is underway. Its detector must be capable of imaging high energy {gamma}-rays from PET while also resolving optical wavelength photons from bioluminescence. GSO, high purity GSO, BGO, LSO, LYSO, and LaBr scintillators were investigated for their use in the OPET detector. Of specific interest were scintillators with low afterglow, since afterglow photons in the decay of the larger {gamma}-ray events are indistinguishable from the photons generated by bioluminescence. Samples from these crystals were coupled to a photomultiplier tube (PMT) and produced scintillation light from {gamma}-ray events originating from a positron source. The PMT output was directed to a special signal processing circuit that allowed measurement of single photons at different times in the decay of the scintillation. GSO and BGO exhibited optimal performance for use in the OPET system due to their low afterglow. LSO, LYSO, and LaBr were determined unsuitable for use with the current OPET design due to their significant afterglow components. The effect of the afterglow of GSO on the detection of the bioluminescence signal-to-noise ratio (SNR) was evaluated for the OPET system.

  17. The very red afterglow of GRB 000418: Further evidence for dust extinction in a gamma-ray burst host galaxy

    DEFF Research Database (Denmark)

    Klose, S.; Stecklum, B.; Masetti, N.

    2000-01-01

    We report near-infrared and optical follow-up observations of the afterglow of the GRB 000418 starting 2.5 days after the occurrence of the burst and extending over nearly 7 weeks. GRB 000418 represents the second case for which the afterglow was initially identified by observations in the near......) bursts are associated with events in star-forming regions....

  18. On the Lack of a Radio Afterglow from Some Gamma-Ray Bursts - Insight into Their Progenitors?

    International Nuclear Information System (INIS)

    Lloyd-Ronning, Nicole Marie; Fryer, Christopher L.

    2017-01-01

    We investigate the intrinsic properties of a sample of bright (with isotropic equivalent energy Eiso > 10 52 erg) gamma-ray bursts (GRBs), comparing those with and without radio afterglow. We find that the sample of bursts with no radio afterglows has a significantly shorter mean intrinsic duration of the prompt gamma-ray radiation, and the distribution of this duration is significantly different from those bursts with a radio afterglow. Although the sample with no radio afterglow has on average lower isotropic energy, the lack of radio afterglow does not appear to be a result of simply energetics of the burst, but a reflection of a separate physical phenomenon likely related to the circumburst density profile. We also find a weak correlation between the isotropic gamma-ray energy and intrinsic duration in the sample with no radio afterglow, but not in the sample that have observed radio afterglows. We give possible explanations for why there may exist a sample of GRBs with no radio afterglow depending on whether the radio emission comes from the forward or reverse shock, and why these bursts appear to have intrinsically shorter prompt emission durations. Lastly, we discuss how our results may have implications for progenitor models of GRBs.

  19. The bright optical afterglow of the nearby gamma-ray burst of 29 March 2003.

    Science.gov (United States)

    Price, P A; Fox, D W; Kulkarni, S R; Peterson, B A; Schmidt, B P; Soderberg, A M; Yost, S A; Berger, E; Djorgovski, S G; Frail, D A; Harrison, F A; Sari, R; Blain, A W; Chapman, S C

    2003-06-19

    Past studies of cosmological gamma-ray bursts (GRBs) have been hampered by their extreme distances, resulting in faint afterglows. A nearby GRB could potentially shed much light on the origin of these events, but GRBs with a redshift z burst of 29 March 2003 (GRB030329; ref. 2). The brightness of the afterglow and the prompt report of its position resulted in extensive follow-up observations at many wavelengths, along with the measurement of the redshift, z = 0.169 (ref. 4). The gamma-ray and afterglow properties of GRB030329 are similar to those of GRBs at cosmological redshifts. Observations have already identified the progenitor as a massive star that exploded as a supernova.

  20. The bright optical flash and afterglow from the gamma-ray burst GRB 130427A.

    Science.gov (United States)

    Vestrand, W T; Wren, J A; Panaitescu, A; Wozniak, P R; Davis, H; Palmer, D M; Vianello, G; Omodei, N; Xiong, S; Briggs, M S; Elphick, M; Paciesas, W; Rosing, W

    2014-01-03

    The optical light generated simultaneously with x-rays and gamma rays during a gamma-ray burst (GRB) provides clues about the nature of the explosions that occur as massive stars collapse. We report on the bright optical flash and fading afterglow from powerful burst GRB 130427A. The optical and >100-megaelectron volt (MeV) gamma-ray flux show a close correlation during the first 7000 seconds, which is best explained by reverse shock emission cogenerated in the relativistic burst ejecta as it collides with surrounding material. At later times, optical observations show the emergence of emission generated by a forward shock traversing the circumburst environment. The link between optical afterglow and >100-MeV emission suggests that nearby early peaked afterglows will be the best candidates for studying gamma-ray emission at energies ranging from gigaelectron volts to teraelectron volts.

  1. Fluorescence and afterglow of Ca2Sn2Al2O9:Mn2+

    Science.gov (United States)

    Takemoto, Minoru; Iseki, Takahiro

    2018-03-01

    By using a polymerized complex method, we synthesized manganese (Mn)-doped Ca2Sn2Al2O9, which exhibits yellow fluorescence and afterglow at room temperature when excited by UV radiation. The material emits a broad, featureless fluorescence band centered at 564 nm, which we attribute to the presence of Mn2+ ions. The afterglow decay is well fit by a power-law function, rather than an exponential function. In addition, thermoluminescence analyses demonstrate that two different types of electron traps form in this material. Based on experimental results, we conclude that the fluorescence and afterglow both result from thermally assisted tunneling, in which trapped electrons are thermally excited to higher-level traps and subsequently tunnel to recombination centers.

  2. GRB 080916C AND GRB 090510: THE HIGH-ENERGY EMISSION AND THE AFTERGLOW

    International Nuclear Information System (INIS)

    Gao Weihong; Mao Jirong; Xu Dong; Fan Yizhong

    2009-01-01

    We constrain the physical composition of the outflows of GRBs 080916C and 090510 with the prompt emission data and find that the former is likely magnetic, while the latter may be baryonic. The X-ray and optical afterglow emission of both GRBs can be reasonably fitted using the standard external shock model but the density profiles of the circum-burst medium are different. We also propose a simple method to estimate the number of seed photons supposing the GeV afterglow photons are due to the inverse Compton radiation of external forward shock electrons. The seed photons needed in the modeling are too many to be realistic for both events. The synchrotron radiation of the forward shock seems able to account for the GeV afterglow data.

  3. On the elimination of the afterglow of CsI(Tl) scintillation detector

    International Nuclear Information System (INIS)

    Alfassi, Z.B.; Ifergan, Y.; Wengrowicz, U.; Weinstein, Marcelo

    2009-01-01

    The use of CsI(Tl) in survey meters is limited to low dose-rate fields due to the afterglow effect, which can take up to 20 min in case of 120 s exposure to 4 R/h field. Even mixtures of low and high dose-rate fields are prohibited since the afterglow effect of the high dose-rate field prevents the use of the meter in the low dose-rate field. It was found that heating the scintillation detector to 60 deg. C shortened considerably the time of the afterglow effect to 3 s, even after exposure of 120 s to fields of 4 R/h. It is suggested to start heating the detector immediately when reaching high dose-rate field and adjusting the calibration to the measured temperature.

  4. Study on the Influence Factors of the Luminous Intensity of the Long Afterglow Luminous Paints

    Directory of Open Access Journals (Sweden)

    Zhao Su

    2016-01-01

    Full Text Available In order to extend the time afterglow luminous powder, enhancement the brightness of luminous paint, this study explore affect long afterglow energy storage luminous paints brightness of the main factors. Luminous paints were prepared with rare earth aluminate long afterglow luminescent powder, first is luminous powder surface modification, then investigate the influence of light emitting powder content, calcium carbonate, titanium dioxide, nano alumina and other fillers on the luminescent properties of the paints. It was concluded that the water resistance of the luminescent powder is better and the brightness can be improved after the modification of anhydrous alcohol. The addition of nano-alumina can improve the brightness of the system, and can effectively enhance the hardness of the paints. In the paints, the two kinds of components of carbonate and titanium dioxide have little effect on the luminescent brightness of the painting.

  5. The Early Time Properties of GRBs - Canonical Afterglows and the Importance of Prolonged Central Engine Activity

    International Nuclear Information System (INIS)

    Melandri, A.; Mundell, C. G.; Kobayashi, S.; Bersier, D.; Steele, I. A.; Smith, R. J.; Carter, D.; Bode, M. F.; Guidorzi, C.; Gomboc, A.

    2009-01-01

    Using a new, comprehensive multiwavelength survey of 63 Gamma Ray Bursts (GRBs) with unprecedented temporal coverage, we classify the observed afterglows into four main classes and discuss the underlying physics that can explain them. The presence or absence of temporal breaks in X-ray and optical bands is used to examine the emission in the context of the standard model; a number of GRBs are shown to deviate from the forward shock model even with the inclusion of energy injection or ambient density gradients. We show that additional emission in the early-time X-ray afterglow due to late-time central engine activity is key and may explain both GRBs whose afterglows do not fit the standard model and those GRBs that appear to be optically dark even at early times.

  6. Population distribution of atomic uranium in the afterglow of a pulsed hollow-cathode discharge

    International Nuclear Information System (INIS)

    Demers, Yves; Gagne, J.-M.; Pianarosa, Piero

    1987-01-01

    From laser absorption measurements we have deduced the time evolution of the population distribution of atomic uranium in the afterglow of a pulsed hollow-cathode type discharge. The vapour generator operates with xenon as the discharge sustaining gas at a pressure of 280 Pa (2.1 Torr). The current pulse characteristics are width 250 μs and height 1.5 A. The pulse repetition frequency is 100 Hz. It is shown that the populations in the three metastable levels at 6249, 3868 and 3800 cm -1 decrease almost exponentially in a time interval between 150 and 300 μs. From 400 μs onwards in the afterglow, the atom population is essentially shared between the ground and the first metastable (620 cm -1 ) levels. Furthermore, starting from 9 ms in the afterglow more than 80% of the U atoms are found in the ground level. (author)

  7. Degravitation, inflation and the cosmological constant as an afterglow

    International Nuclear Information System (INIS)

    Patil, Subodh P.

    2009-01-01

    In this report, we adopt the phenomenological approach of taking the degravitation paradigm seriously as a consistent modification of gravity in the IR, and investigate its consequences for various cosmological situations. We motivate degravitation — where Netwon's constant is promoted to a scale dependent filter function — as arising from either a small (resonant) mass for the graviton, or as an effect in semi-classical gravity. After addressing how the Bianchi identities are to be satisfied in such a set up, we turn our attention towards the cosmological consequences of degravitation. By considering the example filter function corresponding to a resonantly massive graviton (with a filter scale larger than the present horizon scale), we show that slow roll inflation, hybrid inflation and old inflation remain quantitatively unchanged. We also find that the degravitation mechanism inherits a memory of past energy densities in the present epoch in such a way that is likely significant for present cosmological evolution. For example, if the universe underwent inflation in the past due to it having tunneled out of some false vacuum, we find that degravitation implies a remnant 'afterglow' cosmological constant, whose scale immediately afterwards is parametrically suppressed by the filter scale (L) in Planck units Λ ∼ l 2 pl /L 2 . We discuss circumstances through which this scenario reasonably yields the presently observed value for Λ ∼ O(10 −120 ). We also find that in a universe still currently trapped in some false vacuum state, resonance graviton models of degravitation only degravitate initially Planck or GUT scale energy densities down to the presently observed value over timescales comparable to the filter scale. We argue that different functional forms for the filter function will yield similar conclusions. In this way, we argue that although the degravitation models we study have the potential to explain why the cosmological constant is not large

  8. ON THE EMERGENT SPECTRA OF HOT PROTOPLANET COLLISION AFTERGLOWS

    International Nuclear Information System (INIS)

    Miller-Ricci, Eliza; Meyer, Michael R.; Seager, Sara; Elkins-Tanton, Linda

    2009-01-01

    We explore the appearance of terrestrial planets in formation by studying the emergent spectra of hot molten protoplanets during their collisional formation. While such collisions are rare, the surfaces of these bodies may remain hot at temperatures of 1000-3000 K for up to millions of years during the epoch of their formation (of duration 10-100 Myr). These objects are luminous enough in the thermal infrared to be observable with current and next-generation optical/IR telescopes, provided that the atmosphere of the forming planet permits astronomers to observe brightness temperatures approaching that of the molten surface. Detectability of a collisional afterglow depends on properties of the planet's atmosphere-primarily on the mass of the atmosphere. A planet with a thin atmosphere is more readily detected, because there is little atmosphere to obscure the hot surface. Paradoxically, a more massive atmosphere prevents one from easily seeing the hot surface, but also keeps the planet hot for a longer time. In terms of planetary mass, more massive planets are also easier to detect than smaller ones because of their larger emitting surface areas-up to a factor of 10 in brightness between 1 and 10 M + planets. We present preliminary calculations assuming a range of protoplanet masses (1-10 M + ), surface pressures (1-1000 bar), and atmospheric compositions, for molten planets with surface temperatures ranging from 1000 to 1800 K, in order to explore the diversity of emergent spectra that are detectable. While current 8 to 10 m class ground-based telescopes may detect hot protoplanets at wide orbital separations beyond 30 AU (if they exist), we will likely have to wait for next-generation extremely large telescopes or improved diffraction suppression techniques to find terrestrial planets in formation within several AU of their host stars.

  9. Long afterglow properties of Eu2+/Mn2+ doped Zn2GeO4

    International Nuclear Information System (INIS)

    Wan, Minhua; Wang, Yinhai; Wang, Xiansheng; Zhao, Hui; Li, Hailing; Wang, Cheng

    2014-01-01

    Zn 2 GeO 4 :Eu 2+ 0.01 and Zn 2 GeO 4 :Mn 2+ 0.01 long afterglow phosphors were synthesized via a high temperature solid state reaction. X-ray diffraction (XRD), afterglow spectra, decay curves and thermoluminescence curves were utilized to characterize the samples. The X-ray diffraction phases indicate that the doping of small amount of transition metal ions or rare earth ions has no significant influence on the crystal structure of Zn 2 GeO 4 . According to the afterglow spectra, we found that the Zn 2 GeO 4 :Eu 2+ 0.01 exhibits a broad band emission with a peak at 474 nm, which could be ascribed to Eu 2+ transition between 4f 6 5d 1 and 4f 7 electron configurations. The Zn 2 GeO 4 :Mn 2+ 0.01 shows a narrow band emission peaking at 532 nm corresponding to the characteristic transition of Mn 2+ ( 4 T 1 → 6 A 1 ). The thermoluminescence (TL) curves above room temperature are employed for the discussion of the origin of the traps and the mechanism of the persistent luminescence. The results indicate that Zn 2 GeO 4 may be an excellent host material for the rare earth ions or transition metal ions long afterglows. -- Highlights: • Zn 2 GeO 4 :Eu 2+ 0.01 and Zn 2 GeO 4 :Mn 2+ 0.01 long afterglow phosphors were synthesized. • Found that these phosphors possess a persistent luminescence property. • The long afterglow spectra were measured. • Found that these phosphors possess a trap level by thermoluminescence

  10. Revisiting the dispersion measure of fast radio bursts associated with gamma-ray burst afterglows

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yun-Wei, E-mail: yuyw@mail.ccnu.edu.cn [Institute of Astrophysics, Central China Normal University, Wuhan 430079 (China)

    2014-12-01

    Some fast radio bursts (FRBs) are expected to be associated with the afterglow emission of gamma-ray bursts (GRBs), while a short-lived, supermassive neutron star (NS) forms during the GRBs. I investigate the possible contributions to the dispersion measure (DM) of the FRBs from the GRB ejecta and the wind blown from the precollapsing NS. On the one hand, sometimes an internal X-ray plateau afterglow could be produced by the NS wind, which indicates that a great number of electron-positron pairs are carried by the wind. If the pair-generation radius satisfies a somewhat rigorous condition, the relativistic and dense wind would contribute a high DM to the associated FRB, which can be comparable to and even exceed the DM contributed by the intergalactic medium. On the other hand, if the wind only carries a Goldreich-Julian particle flux, its DM contribution would become negligible; meanwhile, the internal plateau afterglow would not appear. Alternatively, the FRB should be associated with a GRB afterglow produced by the GRB external shock, i.e., an energy-injection-caused shallow-decay afterglow or a normal single-power-law afterglow if the impulsive energy release of the GRB is high enough. In the latter case, the DM contributed by the high-mass GRB ejecta could be substantially important, in particular, for an environment of main-sequence stellar wind. In summary, a careful assessment on the various DM contributors could be required for the cosmological application of the expected FRB-GRB association. The future DM measurements of GRB-associated FRBs could provide a constraint on the physics of NS winds.

  11. Revisiting the dispersion measure of fast radio bursts associated with gamma-ray burst afterglows

    International Nuclear Information System (INIS)

    Yu, Yun-Wei

    2014-01-01

    Some fast radio bursts (FRBs) are expected to be associated with the afterglow emission of gamma-ray bursts (GRBs), while a short-lived, supermassive neutron star (NS) forms during the GRBs. I investigate the possible contributions to the dispersion measure (DM) of the FRBs from the GRB ejecta and the wind blown from the precollapsing NS. On the one hand, sometimes an internal X-ray plateau afterglow could be produced by the NS wind, which indicates that a great number of electron-positron pairs are carried by the wind. If the pair-generation radius satisfies a somewhat rigorous condition, the relativistic and dense wind would contribute a high DM to the associated FRB, which can be comparable to and even exceed the DM contributed by the intergalactic medium. On the other hand, if the wind only carries a Goldreich-Julian particle flux, its DM contribution would become negligible; meanwhile, the internal plateau afterglow would not appear. Alternatively, the FRB should be associated with a GRB afterglow produced by the GRB external shock, i.e., an energy-injection-caused shallow-decay afterglow or a normal single-power-law afterglow if the impulsive energy release of the GRB is high enough. In the latter case, the DM contributed by the high-mass GRB ejecta could be substantially important, in particular, for an environment of main-sequence stellar wind. In summary, a careful assessment on the various DM contributors could be required for the cosmological application of the expected FRB-GRB association. The future DM measurements of GRB-associated FRBs could provide a constraint on the physics of NS winds.

  12. Bright x-ray flares in gamma-ray burst afterglows.

    Science.gov (United States)

    Burrows, D N; Romano, P; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

    2005-09-16

    Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We report the discovery of two bright x-ray flares in GRB afterglows, including a giant flare comparable in total energy to the burst itself, each peaking minutes after the burst. These strong, rapid x-ray flares imply that the central engines of the bursts have long periods of activity, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

  13. Observations of Short Gamma-Ray Bursts: Prompt Emission and Afterglow

    Science.gov (United States)

    Berger, Edo

    2011-09-01

    The study of short gamma-ray bursts has been revolutionized by the discovery of afterglows and host galaxies. In this talk I will review observations of the prompt emission, afterglows, and host galaxies, primarily as they pertain to the nature of the progenitor systems. The bulk of the evidence points to the merger of compact objects (NS-NS or NS-BH) making short GRBs the prime candidate for gravitational wave detections with the next generation detectors. This work is partially supported by funds from NASA (through the Swift and Chandra GO programs) and the NSF through an AAG grant.

  14. The early X-ray afterglows of optically bright and dark Gamma-Ray Bursts

    OpenAIRE

    Lin, Yi-Qing

    2006-01-01

    A systematical study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts (B-GRBs and D-GRBs) observed by Swift has been presented. Our sample includes 25 GRBs. Among them 13 are B-GRBs and 12 are D-GRBs. Our results show that the distributions of the X-ray afterglow fluxes ($F_{X}$), the gamma-ray fluxes ($S_{\\gamma}$), and the ratio ($R_{\\gamma, X}$) for both the D-GRBs and B-GRBs are similar. The differences of these distributions for the two kinds of GRBs shoul...

  15. Optically selected GRB afterglows, a real time analysis system at the CFHT

    International Nuclear Information System (INIS)

    Malacrino, F.; Atteia, J.-L.; Klotz, A.; Boer, M.; Kavelaars, J.J.; Cuillandre, J.-C.

    2005-01-01

    We attempt to detect optical GRB afterglows on images taken by the Canada France Hawaii Telescope for the Very Wide survey, component of the Legacy Survey. To do so, a Real Time Analysis System called Optically Selected GRB Afterglows has been installed on a dedicated computer in Hawaii. This pipeline automatically and quickly analyzes Mega cam images and extracts from them a list of variable objects which is displayed on a web page far validation by a member of the collaboration. The Very Wide survey covers 1200 square degrees down to i 1 = 23.5. This paper briefly explain the RTAS process

  16. The Faint Optical Afterglow and Host Galaxy of GRB 020124: Implications for the Nature of Dark Gamma-Ray Bursts

    Science.gov (United States)

    Berger, E.; Kulkarni, S. R.; Bloom, J. S.; Price, P. A.; Fox, D. W.; Frail, D. A.; Axelrod, T. S.; Chevalier, R. A.; Colbert, E.; Costa, E.; Djorgovski, S. G.; Frontera, F.; Galama, T. J.; Halpern, J. P.; Harrison, F. A.; Holtzman, J.; Hurley, K.; Kimble, R. A.; McCarthy, P. J.; Piro, L.; Reichart, D.; Ricker, G. R.; Sari, R.; Schmidt, B. P.; Wheeler, J. C.; Vanderppek, R.; Yost, S. A.

    2002-12-01

    We present ground-based optical observations of GRB 020124 starting 1.6 hr after the burst, as well as subsequent Very Large Array and Hubble Space Telescope (HST) observations. The optical afterglow of GRB 020124 is one of the faintest afterglows detected to date, and it exhibits a relatively rapid decay, Fν~t-1.60+/-0.04, followed by further steepening. In addition, a weak radio source was found coincident with the optical afterglow. The HST observations reveal that a positionally coincident host galaxy must be the faintest host to date, R>~29.5 mag. The afterglow observations can be explained by several models requiring little or no extinction within the host galaxy, AhostV~0-0.9 mag. These observations have significant implications for the interpretation of the so-called dark bursts (bursts for which no optical afterglow is detected), which are usually attributed to dust extinction within the host galaxy. The faintness and relatively rapid decay of the afterglow of GRB 020124, combined with the low inferred extinction, indicate that some dark bursts are intrinsically dim and not dust obscured. Thus, the diversity in the underlying properties of optical afterglows must be observationally determined before substantive inferences can be drawn from the statistics of dark bursts.

  17. TESTING MODELS FOR THE SHALLOW DECAY PHASE OF GAMMA-RAY BURST AFTERGLOWS WITH POLARIZATION OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Mi-Xiang; Dai, Zi-Gao [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, Xue-Feng, E-mail: dzg@nju.edu.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-08-01

    The X-ray afterglows of almost one-half of gamma-ray bursts have been discovered by the Swift satellite to have a shallow decay phase of which the origin remains mysterious. Two main models have been proposed to explain this phase: relativistic wind bubbles (RWBs) and structured ejecta, which could originate from millisecond magnetars and rapidly rotating black holes, respectively. Based on these models, we investigate polarization evolution in the shallow decay phase of X-ray and optical afterglows. We find that in the RWB model, a significant bump of the polarization degree evolution curve appears during the shallow decay phase of both optical and X-ray afterglows, while the polarization position angle abruptly changes its direction by 90°. In the structured ejecta model, however, the polarization degree does not evolve significantly during the shallow decay phase of afterglows whether the magnetic field configuration in the ejecta is random or globally large-scale. Therefore, we conclude that these two models for the shallow decay phase and relevant central engines would be testable with future polarization observations.

  18. Dust extinction in high-z galaxies with gamma-ray burst afterglow spectroscopy

    DEFF Research Database (Denmark)

    Elíasdóttir, Á.; Fynbo, J. P. U.; Hjorth, J.

    2009-01-01

    We report the clear detection of the 2175 Å dust absorption feature in the optical afterglow spectrum of the gamma-ray burst (GRB) GRB 070802 at a redshift of z = 2.45. This is the highest redshift for a detected 2175 Å dust bump to date, and it is the first clear detection of the 2175 Å bump...

  19. Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB030329.

    Science.gov (United States)

    Greiner, Jochen; Klose, Sylvio; Reinsch, Klaus; Schmid, Hans Martin; Sari, Re'em; Hartmann, Dieter H; Kouveliotou, Chryssa; Rau, Arne; Palazzi, Eliana; Straubmeier, Christian; Stecklum, Bringfried; Zharikov, Sergej; Tovmassian, Gaghik; Bärnbantner, Otto; Ries, Christoph; Jehin, Emmanuel; Henden, Arne; Kaas, Anlaug A; Grav, Tommy; Hjorth, Jens; Pedersen, Holger; Wijers, Ralph A M J; Kaufer, Andreas; Park, Hye-Sook; Williams, Grant; Reimer, Olaf

    2003-11-13

    The association of a supernova with GRB030329 strongly supports the 'collapsar' model of gamma-ray bursts, where a relativistic jet forms after the progenitor star collapses. Such jets cannot be spatially resolved because gamma-ray bursts lie at cosmological distances; their existence is instead inferred from 'breaks' in the light curves of the afterglows, and from the theoretical desire to reduce the estimated total energy of the burst by proposing that most of it comes out in narrow beams. Temporal evolution of the polarization of the afterglows may provide independent evidence for the jet structure of the relativistic outflow. Small-level polarization ( approximately 1-3 per cent) has been reported for a few bursts, but its temporal evolution has yet to be established. Here we report polarimetric observations of the afterglow of GRB030329. We establish the polarization light curve, detect sustained polarization at the per cent level, and find significant variability. The data imply that the afterglow magnetic field has a small coherence length and is mostly random, probably generated by turbulence, in contrast with the picture arising from the high polarization detected in the prompt gamma-rays from GRB021206 (ref. 18).

  20. GRB 110530A: Peculiar Broad Bump and Delayed Plateau in Early Optical Afterglows

    Science.gov (United States)

    Zhong, Shu-Qing; Xin, Li-Ping; Liang, En-Wei; Wei, Jian-Yan; Urata, Yuji; Huang, Kui-Yun; Qiu, Yu-Lei; Deng, Can-Min; Wang, Yuan-Zhu; Deng, Jin-Song

    2016-11-01

    We report our very early optical observations of GRB 110530A and investigate its jet properties together with its X-ray afterglow data. A peculiar broad onset bump followed by a plateau is observed in its early R band afterglow light curve. The optical data in the other bands and the X-ray data are well consistent with the temporal feature of the R band light curve. Our joint spectral fits of the optical and X-ray data show that they are in the same regime, with a photon index of ∼1.70. The optical and X-ray afterglow light curves are well fitted with the standard external shock model by considering a delayed energy injection component. Based on our modeling results, we find that the radiative efficiency of the gamma-ray burst jet is ∼ 1 % and the magnetization parameter of the afterglow jet is \\lt 0.04 with a derived extremely low {ε }B (the ratio of shock energy to the magnetic field) of (1.64+/- 0.25)× {10}-6. These results indicate that the jet may be matter dominated. A discussion on delayed energy injection from the accretion of the late fall-back material of its pre-supernova star is also presented.

  1. Afterglow luminescence in sol-gel/Pechini grown oxide materials: persistence or phosphorescence process? (Conference Presentation)

    Science.gov (United States)

    Sontakke, Atul; Ferrier, Alban; Viana, Bruno

    2017-03-01

    Persistent luminescence and phosphorescence, both yields afterglow luminescence, but are completely different mechanisms. Persistent luminescence involves a slow thermal release of trapped electrons stored in defect states, whereas the phosphorescence is caused due to triplet to singlet transition [1,2]. Many persistent luminescence phosphors are based on oxide inorganic hosts, and exhibit long afterglow luminescence after ceasing the excitation. We observed intense and long afterglow luminescence in sol-gel/pechini grown inorganic oxides, and as a first interpretation thought to be due to persistence mechanism. However, some of these materials do not exhibit defect trap centers, and a detailed investigation suggested it is due to phosphorescence, but not the persistence. Phosphorescence is not common in inorganic solids, and that too at room temperature, and therefore usually misinterpreted as persistence luminescence [3]. Here we present a detailed methodology to distinguish phosphorescence from persistence luminescence in inorganic solids, and the process to harvest highly efficient long phosphorescence afterglow at room temperature. 1. Jian Xu, Setsuhisa Tanabe, Atul D. Sontakke, Jumpei Ueda, Appl. Phys. Lett. 107, 081903 (2015) 2. Sebastian Reineke, Marc A. Baldo, Scientific Reports, 4, 3797 (2014) 3. Pengchong Xue, Panpan Wang, Peng Chen, Boqi Yao, Peng Gong, Jiabao Sun, Zhenqi Zhang, Ran Lu, Chem. Sci. (2016) DOI: 10.1039/C5SC03739E

  2. Revisiting gamma-ray burst afterglows with time-dependent parameters

    Science.gov (United States)

    Yang, Chao; Zou, Yuan-Chuan; Chen, Wei; Liao, Bin; Lei, Wei-Hua; Liu, Yu

    2018-02-01

    The relativistic external shock model of gamma-ray burst (GRB) afterglows has been established with five free parameters, i.e., the total kinetic energy E, the equipartition parameters for electrons {{ε }}{{e}} and for the magnetic field {{ε }}{{B}}, the number density of the environment n and the index of the power-law distribution of shocked electrons p. A lot of modified models have been constructed to consider the variety of GRB afterglows, such as: the wind medium environment by letting n change with radius, the energy injection model by letting kinetic energy change with time and so on. In this paper, by assuming all four parameters (except p) change with time, we obtain a set of formulas for the dynamics and radiation, which can be used as a reference for modeling GRB afterglows. Some interesting results are obtained. For example, in some spectral segments, the radiated flux density does not depend on the number density or the profile of the environment. As an application, through modeling the afterglow of GRB 060607A, we find that it can be interpreted in the framework of the time dependent parameter model within a reasonable range.

  3. Revisited kinetics of the short lived afterglow of a nitrogen microwave discharge

    NARCIS (Netherlands)

    Foissac, C.; Supiot, P.; Mazouffre, S.; Engeln, R.A.H.; Schram, D.C.; Sadeghi, N.; Campargue, A.; Stoffels, W.W.

    2001-01-01

    Nitrogen discharges and afterglows at pressures of a few hundreds of Pascal have been very extensively studied in the past two decades. However, most of the experimental works are based on emission spectroscopy and so far no overall description of the plasma together with the kinetics of the neutral

  4. The afterglow, redshift and extreme energetics of the gamma-ray burst of 23 January 1999

    NARCIS (Netherlands)

    Kulkarni, [No Value; Djorgovski, SG; Odewahn, SC; Bloom, JS; Gal, RR; Koresko, CD; Harrison, FA; Lubin, LM; Armus, L; Sari, R; Illingworth, GD; Kelson, DD; Magee, DK; van Dokkum, PG; Frail, DA; Mulchaey, JS; Malkan, MA; McClean, IS; Teplitz, HI; Koerner, D; Kirkpatrick, D; Kobayashi, N; Yadigaroglu, IA; Halpern, J; Piran, T; Goodrich, RW; Chaffee, FH; Feroci, M; Costa, E

    1999-01-01

    Long-lived emission, known as afterglow, has now been detected from about a dozen gamma-ray bursts. Distance determinations place the bursts at cosmological distances, with redshifts,z, ranging from similar to 1 to 3, The energy required to produce these bright gamma-ray flashes is enormous: up to

  5. Long-term continuous energy injection in the afterglow of GRB 060729

    International Nuclear Information System (INIS)

    Xu Ming; Huang Yongfeng; Lu Tan

    2009-01-01

    A long plateau phase and an amazing level of brightness have been observed in the X-ray afterglow of GRB 060729. This peculiar light curve is likely due to long-term energy injection in external shock. Here, we present a detailed numerical study of the energy injection process of magnetic dipole radiation from a strongly magnetized millisecond pulsar and model the multi-band afterglow observations. It is found that this model can successfully explain the long plateaus in the observed X-ray and optical afterglow light curves. The sharp break following the plateaus could be due to the rapid decline of the emission power of the central pulsar. At an even later time (∼ 5 x 10 6 s), an obvious jet break appears, which implies a relatively large half opening angle of θ ∼ 0.3 for the GRB ejecta. Due to the energy injection, the Lorentz factor of the outflow is still larger than two even at 10 7 s after the GRB trigger, making the X-ray afterglow of this burst detectable by Chandra even 642 d after the burst.

  6. Deep Photometry of GRB 041006 Afterglow: Hypernova Bump at Redshift z = 0.716

    Science.gov (United States)

    Stanek, K. Z.; Garnavich, P. M.; Nutzman, P. A.; Hartman, J. D.; Garg, A.; Adelberger, K.; Berlind, P.; Bonanos, A. Z.; Calkins, M. L.; Challis, P.; Gaudi, B. S.; Holman, M. J.; Kirshner, R. P.; McLeod, B. A.; Osip, D.; Pimenova, T.; Reiprich, T. H.; Romanishin, W.; Spahr, T.; Tegler, S. C.; Zhao, X.

    2005-06-01

    We present deep optical photometry of the afterglow of gamma-ray burst (GRB) 041006 and its associated hypernova obtained over 65 days after detection (55 R-band epochs on 10 different nights). Our early data (tVatican Advanced Technology Telescope, the Magellan 6.5 m Baade and Clay telescopes, and the Keck II 10 m telescope.

  7. GRB060206 and the quandary of achromatic breaks in afterglow light curves

    NARCIS (Netherlands)

    Curran, P.A.; van der Horst, A.J.; Wijers, R.A.M.J.; Starling, R.L.C.; Castro-Tirado, A.J.; Fynbo, J.P.U.; Gorosabel, J.; Järvinen, A.S.; Malesani, D.; Rol, E.; Tanvir, N.R.; Wiersema, K.; Burleigh, M.R.; Casewell, S.L.; Dobbie, P.D.; Guziy, S.; Jakobsson, P.; Jelínek, M.; Laursen, P.; Levan, A.J.; Mundell, C.G.; Näränen, J.; Piranomonte, S.

    2007-01-01

    Gamma-ray burst afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared with the BeppoSAX era. We present our multi-wavelength analysis of GRB060206 as an illustrative example of how inferences of jet breaks from optical and X-ray data might differ. The

  8. Implications of the Early X-Ray Afterglow Light Curves of Swift GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Granot, Jonathan; /KIPAC, Menlo Park; Konigl, Arieh; /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI; Piran, Tsvi; /Hebrew U.

    2006-01-17

    According to current models, gamma-ray bursts (GRBs) are produced when the energy carried by a relativistic outflow is dissipated and converted into radiation. The efficiency of this process, {epsilon}{sub {gamma}}, is one of the critical factors in any GRB model. The X-ray afterglow light curves of Swift GRBs show an early stage of flattish decay. This has been interpreted as reflecting energy injection. When combined with previous estimates, which have concluded that the kinetic energy of the late ({approx}> 10 hr) afterglow is comparable to the energy emitted in {gamma}-rays, this interpretation implies very high values of {epsilon}{sub {gamma}}, corresponding to {approx}> 90% of the initial energy being converted into {gamma}-rays. Such a high efficiency is hard to reconcile with most models, including in particular the popular internal-shocks model. We re-analyze the derivation of the kinetic energy from the afterglow X-ray flux and re-examine the resulting estimates of the efficiency. We confirm that, if the flattish decay arises from energy injection and the pre-Swift broad-band estimates of the kinetic energy are correct, then {epsilon}{sub {gamma}} {approx}> 0.9. We discuss various issues related to this result, including an alternative interpretation of the light curve in terms of a two-component outflow model, which we apply to the X-ray observations of GRB 050315. We point out, however, that another interpretation of the flattish decay--a variable X-ray afterglow efficiency (e.g., due to a time dependence of afterglow shock microphysical parameters)--is possible. We also show that direct estimates of the kinetic energy from the late X-ray afterglow flux are sensitive to the assumed values of the shock microphysical parameters and suggest that broad-band afterglow fits might have underestimated the kinetic energy (e.g., by overestimating the fraction of electrons that are accelerated to relativistic energies). Either one of these possibilities implies a

  9. Structure in the early afterglow light curve of the gamma-ray burst of 29 March 2003.

    Science.gov (United States)

    Uemura, Makoto; Kato, Taichi; Ishioka, Ryoko; Yamaoka, Hitoshi; Monard, Berto; Nogami, Daisaku; Maehara, Hiroyuki; Sugie, Atsushi; Takahashi, Susumu

    2003-06-19

    Gamma-ray bursts (GRBs) are energetic explosions that for 0.01-100 s are the brightest gamma-ray sources in the sky. Observations of the early evolution of afterglows are expected to provide clues about the nature of the bursts, but their rapid fading has hampered such studies; some recent rapid localizations of bursts have improved the situation. Here we report an early detection of the very bright afterglow of the burst of 29 March 2003 (GRB030329). Our data show that, even early in the afterglow phase, the light curve shows unexpectedly complicated structures superimposed on the fading background.

  10. Ultrahigh energy neutrino afterglows of nearby long duration gamma-ray bursts

    Science.gov (United States)

    Thomas, Jessymol K.; Moharana, Reetanjali; Razzaque, Soebur

    2017-11-01

    Detection of ultrahigh energy (UHE, ≳1 PeV ) neutrinos from astrophysical sources will be a major advancement in identifying and understanding the sources of UHE cosmic rays (CRs) in nature. Long duration gamma-ray burst (GRB) blast waves have been considered as potential acceleration sites of UHECRs. These CRs are expected to interact with GRB afterglow photons, which are synchrotron radiation from relativistic electrons coaccelerated with CRs in the blast wave, and naturally produce UHE neutrinos. Fluxes of these neutrinos are uncertain, however, and crucially depend on the observed afterglow modeling. We have selected a sample of 23 long duration GRBs within redshift 0.5 for which adequate electromagnetic afterglow data are available and which could produce high flux of UHE afterglow neutrinos, being nearby. We fit optical, x-ray, and γ -ray afterglow data with an adiabatic blast wave model in a constant density interstellar medium and in a wind environment where the density of the wind decreases as the inverse square of the radius from the center of the GRB. The blast wave model parameters extracted from these fits are then used for calculating UHECR acceleration and p γ interactions to produce UHE neutrino fluxes from these GRBs. We have also explored the detectability of these neutrinos by currently running and upcoming large area neutrino detectors, such as the Pierre Auger Observatory, IceCube Gen-2, and KM3NeT observatories. We find that our realistic flux models from nearby GRBs will be unconstrained in the foreseeable future.

  11. The puzzling afterglow of GRB 050721: a rebrightening seen in the optical but not in the X-ray

    International Nuclear Information System (INIS)

    Antonelli, L. A.; Romano, P.; Testa, V.; D'Elia, V.; Guetta, D.; Torii, K.; Malesani, D.

    2007-01-01

    We present here the analysis of the early and late multiwavelength afterglow emission, as observed by Swift a small robotic telescope, and the VLT. We compare early observations with late afterglow observations obtained with Swift and the VLT and we observe an intense rebrightening in the optical band at about one day after the burst which is not present in the X-ray band. The lack of detection in X-ray of such a strong rebrightening at lower energies may be described with a variable external density profile. In such a scenario, the combined X-ray and optical observations allow us to derive that the matter density located at ∼ 1017 cm from the burst is about a factor of 10 higher than in the inner region. This is the first time in which a rebrightening has been observed in the optical afterglow of a GRB that is clearly absent in the X-ray afterglow

  12. Investigation on luminescence enhancement and decay characteristics of long afterglow nanophosphors for dark-vision display applications

    Energy Technology Data Exchange (ETDEWEB)

    Swati, G.; Chawla, S.; Mishra, S.; Rajesh, B.; Vijayan, N.; Sivaiah, B.; Dhar, A.; Haranath, D., E-mail: haranath@nplindia.org

    2015-04-01

    Graphical abstract: - Highlights: • Synthesis and structural characterization has been performed on long afterglow SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} nanophosphor having afterglow time of ∼12 h. • Studied the effect of various fuels used for synthesis of nanophosphors on the decay and luminescence characteristics. Interestingly, afterglow times varied significantly with different fuels used for the synthesis of the nanophosphor. • Excitation by different illuminants has profound influence on the luminescence intensity and afterglow times of the synthesized nanophosphor. • Such studies could be guidelines for appropriate usage of nanophosphor under different lighting environment. - Abstract: Long afterglow SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+} nanophosphors were synthesized via a facile but effectual auto-combustion technique followed by post-annealing treatment at elevated temperatures. The influence of various fuels during synthesis and thereafter improvement in the luminescence decay characteristics under various illuminant irradiations of long afterglow nanophosphors have been reported. Extensive studies on structural, morphological and luminescent properties of the as-synthesized afterglow nanophosphors have been presented. Powder X-ray diffraction studies confirm the presence of high-purity, single-phase monoclinic nanophosphors. HRTEM investigations confirm the formation of nanophosphors of particle size less than 50 nm. Photoluminescence emission is attributed to the characteristic d–f transition (4f{sup 6}5d{sup 1}→4f{sup 7}) of Eu{sup 2+} ions and was positioned at 512 nm. As-synthesized nanophosphors exhibit considerable confinement effects resulting into blue shift in emission maxima as compared to their bulk counterparts. The mechanism underlined for long afterglow has been discussed using trapping–detrapping model. The nanophosphor being multifunctional finds many interesting applications including dark-vision display

  13. Blue–green afterglow of BaAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Bao-gai [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China); Ma, Qing-lan [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China); School of Electronics and Information, Nantong University, Jiangsu 226019 (China); Xiong, Rui [School of Physics and Technology, Wuhan University, Hubei 430072 (China); Li, Xiazhang [Analysis and Testing Center, Changzhou University, Jiangsu 213164 (China); Huang, Yuan Ming, E-mail: dongshanisland@126.com [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China)

    2016-03-15

    Highlights: • Afterglow can be achieved when Eu{sup 2+} is absent in the DyAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors. • The afterglow of DyAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors is discernible to naked eyes for minutes. • Dy{sup 3+} introduced trap centers are believed to be responsible for the afterglow. - Abstract: Dy{sup 3+} doped barium aluminate (BaAl{sub 2}O{sub 4}:Dy{sup 3+}) phosphors were prepared via the sol–gel combustion route at the ignition temperature of 600 °C. The phosphors were characterized with X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Regardless of the absence of Eu{sup 2+} luminescent centers, broadband blue–green afterglow with its peak at about 490 nm was recorded in the BaAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors. The decay profile of the blue–green afterglow can be best fitted into a two-component exponential function with the two lifetime decay constants to be 8.81 and 45.25 s, respectively. The observation of blue–green afterglow from BaAl{sub 2}O{sub 4}:Dy{sup 3+} in the absence of Eu{sup 2+} provides unique opportunity in unveiling the afterglow mechanisms of rare-earth doped alkaline-metal aluminates. Possible mechanisms on the blue–green afterglow in BaAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors are discussed in terms of the Dy{sup 3+} ions introduced trap centers as well as luminescent centers in the crystal lattice.

  14. THE PROPERTIES OF THE 2175 Å EXTINCTION FEATURE DISCOVERED IN GRB AFTERGLOWS

    International Nuclear Information System (INIS)

    Zafar, Tayyaba; Watson, Darach; Elíasdóttir, Árdís; Fynbo, Johan P. U.; Krühler, Thomas; Leloudas, Giorgos; Schady, Patricia; Greiner, Jochen; Jakobsson, Páll; Thöne, Christina C.; Perley, Daniel A.; Morgan, Adam N.; Bloom, Joshua

    2012-01-01

    The unequivocal, spectroscopic detection of the 2175 Å bump in extinction curves outside the Local Group is rare. To date, the properties of the bump have been examined in only two gamma-ray burst (GRB) afterglows (GRB 070802 and GRB 080607). In this work, we analyze in detail the detections of the 2175 Å extinction bump in the optical spectra of two further GRB afterglows: GRB 080605 and 080805. We gather all available optical/near-infrared photometric, spectroscopic, and X-ray data to construct multi-epoch spectral energy distributions (SEDs) for both GRB afterglows. We fit the SEDs with the Fitzpatrick and Massa model with a single or broken power law. We also fit a sample of 38 GRB afterglows, known to prefer a Small Magellanic Cloud (SMC)-type extinction curve, with the same model. We find that the SEDs of GRB 080605 and GRB 080805 at two epochs are fit well with a single power law with a derived extinction of A V = 0.52 +0.13 –0.16 and 0.50 +0.13 –0.10 , and 2.1 +0.7 –0.6 and 1.5 ± 0.2, respectively. While the slope of the extinction curve of GRB 080805 is not well constrained, the extinction curve of GRB 080605 has an unusual very steep far-UV rise together with the 2175 Å bump. Such an extinction curve has previously been found in only a small handful of sightlines in the Milky Way. One possible explanation of such an extinction curve may be dust arising from two different regions with two separate grain populations, however we cannot distinguish the origin of the curve. We finally compare the four 2175 Å bump sightlines to the larger GRB afterglow sample and to Local Group sightlines. We find that while the width and central positions of the bumps are consistent with what is observed in the Local Group, the relative strength of the detected bump (A bump ) for GRB afterglows is weaker for a given A V than for almost any Local Group sightline. Such dilution of the bump strength may offer tentative support to a dual dust-population scenario.

  15. Afterglow Observations Shed New Light on the Nature of X-ray Flashes

    Energy Technology Data Exchange (ETDEWEB)

    Granot, J

    2005-02-17

    X-ray flashes (XRFs) and X-ray rich gamma-ray bursts (XRGRBs) share many observational characteristics with long duration ({approx}> 2 s) GRBs, but the reason for which the spectral energy distribution of their prompt emission peaks at lower photon energies, E{sub p}, is still a subject of debate. Although many different models have been invoked in order to explain the lower values of E{sub p}, their implications for the afterglow emission were not considered in most cases, mainly because observations of XRF afterglows have become available only recently. Here we examine the predictions of the various XRF models for the afterglow emission, and test them against the observations of XRF 030723 and XRGRB 041006, the events with the best monitored afterglow light curves in their respective class. We show that most existing XRF models are hard to reconcile with the observed afterglow light curves, which are very flat at early times. Such light curves are, however, naturally produced by a roughly uniform jet with relatively sharp edges that is viewed off-axis (i.e. from outside of the jet aperture). This type of model self consistently accommodates both the observed prompt emission and the afterglow light curves of XRGRB 041006 and XRF 030723, implying viewing angles {theta}{sub obs} from the jet axis of ({theta}{sub obs}-{theta}{sub 0}) {approx} 0.15 {theta}{sub 0} and ({theta}{sub obs}-{theta}{sub 0}) {approx} {theta}{sub 0}, respectively, where {theta}{sub 0} {approx} 3{sup o} is the half-opening angle of the jet. This suggests that GRBs, XRGRBs and XRFs are intrinsically similar relativistic jets viewed from different angles. It is then natural to identify GRBs with {gamma}({theta}{sub obs} - {theta}{sub 0}) {approx}< 1, XRGRBs with 1 {approx}< ({theta}{sub obs} - {theta}{sub 0}) {approx}< a few, and XRFs with {gamma}({theta}{sub obs} - {theta}{sub 0}) {approx}> a few, where {gamma} is the Lorentz factor of the outflow near the edge of the jet from which most of the

  16. The Very Red Afterglow of GRB 000418: Further Evidence for Dust Extinction in a Gamma-Ray Burst Host Galaxy

    Science.gov (United States)

    Klose, S.; Stecklum, B.; Masetti, N.; Pian, E.; Palazzi, E.; Henden, A. A.; Hartmann, D. H.; Fischer, O.; Gorosabel, J.; Sánchez-Fernández, C.; Butler, D.; Ott, Th.; Hippler, S.; Kasper, M.; Weiss, R.; Castro-Tirado, A.; Greiner, J.; Bartolini, C.; Guarnieri, A.; Piccioni, A.; Benetti, S.; Ghinassi, F.; Magazzú, A.; Hurley, K.; Cline, T.; Trombka, J.; McClanahan, T.; Starr, R.; Goldsten, J.; Gold, R.; Mazets, E.; Golenetskii, S.; Noeske, K.; Papaderos, P.; Vreeswijk, P. M.; Tanvir, N.; Oscoz, A.; Muñoz, J. A.; Castro Cerón, J. M.

    2000-12-01

    We report near-infrared and optical follow-up observations of the afterglow of the GRB 000418 starting 2.5 days after the occurrence of the burst and extending over nearly 7 weeks. GRB 000418 represents the second case for which the afterglow was initially identified by observations in the near-infrared. During the first 10 days its R-band afterglow was well characterized by a single power-law decay with a slope of 0.86. However, at later times the temporal evolution of the afterglow flattens with respect to a simple power-law decay. Attributing this to an underlying host galaxy, we find its magnitude to be R=23.9 and an intrinsic afterglow decay slope of 1.22. The afterglow was very red with R-K~4 mag. The observations can be explained by an adiabatic, spherical fireball solution and a heavy reddening due to dust extinction in the host galaxy. This supports the picture that (long) bursts are associated with events in star-forming regions. Based on observations collected at the Bologna Astronomical Observatory in Loiano, Italy; at the TNG, Canary Islands, Spain; at the German-Spanish Astronomical Centre, Calar Alto, operated by the Max-Planck-Institut for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy; at the US Naval Observatory; and at the UK Infrared Telescope.

  17. STATISTICAL PROPERTIES OF GRB AFTERGLOW PARAMETERS AS EVIDENCE OF COSMOLOGICAL EVOLUTION OF THEIR HOST GALAXIES

    Directory of Open Access Journals (Sweden)

    Gregory Beskin

    2014-08-01

    Full Text Available The results of a study of 43 peaked R-band light curves of optical counterparts of gamma-ray bursts with known redshifts are presented. The parameters of optical transients were calculated in the comoving frame, and then a search for pair correlations between them was conducted. A statistical analysis showed a strong correlation between the peak luminosity and the redshift both for pure afterglows and for events with residual gamma activity, which cannot be explained as an effect of observational selection.This suggests a cosmological evolution of the parameters of the local interstellar medium around the sources of the gamma-ray burst. In the models of forward and reverse shock waves, a relation between the density of the interstellar medium and the redshift was built for gamma-ray burst afterglows, leading to a power-law dependence of the star-formation rate at regions around GRBs on redshift with a slope of about 6.

  18. DARK BURSTS IN THE SWIFT ERA: THE PALOMAR 60 INCH-SWIFT EARLY OPTICAL AFTERGLOW CATALOG

    International Nuclear Information System (INIS)

    Cenko, S. B.; Harrison, F. A.; Kelemen, J.; Fox, D. B.; Kulkarni, S. R.; Kasliwal, M. M.; Ofek, E. O.; Rau, A.; Gal-Yam, A.; Frail, D. A.; Moon, D.-S.

    2009-01-01

    We present multicolor optical observations of long-duration γ-ray bursts (GRBs) made over a three-year period with the robotic Palomar 60 inch telescope (P60). Our sample consists of all 29 events discovered by Swift for which P60 began observations less than 1 hr after the burst trigger. We were able to recover 80% of the optical afterglows from this prompt sample, and we attribute this high efficiency to our red coverage. Like Melandri et al. (2008), we find that a significant fraction (∼50%) of Swift events show a suppression of the optical flux with regard to the X-ray emission (the so-called 'dark' bursts). Our multicolor photometry demonstrates this is likely due in large part to extinction in the host galaxy. We argue that previous studies, by selecting only the brightest and best-sampled optical afterglows, have significantly underestimated the amount of dust present in typical GRB environments.

  19. Constraining chameleon field theories using the GammeV afterglow experiments

    International Nuclear Information System (INIS)

    Upadhye, A.; Steffen, J.H.; Weltman, A.

    2009-01-01

    The GammeV experiment has constrained the couplings of chameleon scalar fields to matter and photons. Here we present a detailed calculation of the chameleon afterglow rate underlying these constraints. The dependence of GammeV constraints on various assumptions in the calculation is studied. We discuss GammeV-CHASE, a second-generation GammeV experiment, which will improve upon GammeV in several major ways. Using our calculation of the chameleon afterglow rate, we forecast model-independent constraints achievable by GammeV-CHASE. We then apply these constraints to a variety of chameleon models, including quartic chameleons and chameleon dark energy models. The new experiment will be able to probe a large region of parameter space that is beyond the reach of current tests, such as fifth force searches, constraints on the dimming of distant astrophysical objects, and bounds on the variation of the fine structure constant.

  20. Pinus Pinaster surface treatment realized in spatial and temporal afterglow DBD conditions

    Science.gov (United States)

    Lecoq, E.; Clément, F.; Panousis, E.; Loiseau, J.-F.; Held, B.; Castetbon, A.; Guimon, C.

    2008-04-01

    This experimental work deals with the exposition of Pinus Pinaster wood samples to a DBD afterglow. Electrical parameters like duty cycle and injected energy in the gas are being varied and the modifications induced by the afterglow on the wood are analysed by several macroscopic and microscopic ways like wettability, XPS analyses and also soaking tests of treated wood in a commercial fungicide solution. Soaking tests show that plasma treatment could enhance the absorption of fungicide into the wood. The wettability results point out that the plasma treatment can inflict on the wood different surface properties, making it hydrophilic or hydrophobic, when varying electrical parameters. XPS analyses reveal several chemical modifications like an increase of the O/C ratio and the presence of carboxyl groups on the surface after plasma treatments.

  1. An Estimation of the Gamma-Ray Burst Afterglow Apparent Optical Brightness Distribution Function

    Science.gov (United States)

    Akerlof, Carl W.; Swan, Heather F.

    2007-12-01

    By using recent publicly available observational data obtained in conjunction with the NASA Swift gamma-ray burst (GRB) mission and a novel data analysis technique, we have been able to make some rough estimates of the GRB afterglow apparent optical brightness distribution function. The results suggest that 71% of all burst afterglows have optical magnitudes with mRa strong indication that the apparent optical magnitude distribution function peaks at mR~19.5. Such estimates may prove useful in guiding future plans to improve GRB counterpart observation programs. The employed numerical techniques might find application in a variety of other data analysis problems in which the intrinsic distributions must be inferred from a heterogeneous sample.

  2. Impact of aerosol particles on the structure of an atmospheric pressure microwave plasma afterglow

    Energy Technology Data Exchange (ETDEWEB)

    Chen Chunku [Ceramic and Composite Materials Centre, 209 Farris Engineering Centre, University of New Mexico, Albuquerque, NM (United States); Phillips, Jonathan [Los Alamos National Laboratory, MS C930, Los Alamos, NM (United States)

    2002-05-21

    Several novel ceramic processing technologies (e.g. oxide ceramic melting and spheroidization) using an atmospheric pressure microwave plasma torch were recently developed in our lab. Understanding the processes and optimization requires complete characterization of the plasma as a function of operating condition. As a first step, a non-intrusive spectroscopic method was employed to map rotational (gas), electron and excitation temperatures and electron densities of the afterglow region of microwave generated atmospheric plasmas with and without alumina particle aerosol. Two-dimensional spatially resolved mapping of rotational (gas), excitation and electron temperatures and electron densities as a function of operating conditions during material processing were developed. It was shown that the passage of an aerosol dramatically changes the structure of the afterglow. Also the non-equilibrium nature of microwave generated atmospheric argon plasma was confirmed, suggesting that only multi-temperature models are capable of modelling this region of the plasma. (author)

  3. Efficient electron heating in relativistic shocks and gamma-ray-burst afterglow.

    Science.gov (United States)

    Gedalin, M; Balikhin, M A; Eichler, D

    2008-02-01

    Electrons in shocks are efficiently energized due to the cross-shock potential, which develops because of differential deflection of electrons and ions by the magnetic field in the shock front. The electron energization is necessarily accompanied by scattering and thermalization. The mechanism is efficient in both magnetized and nonmagnetized relativistic electron-ion shocks. It is proposed that the synchrotron emission from the heated electrons in a layer of strongly enhanced magnetic field is responsible for gamma-ray-burst afterglows.

  4. Phenomenology of reverse-shock emission in the optical afterglows of gamma-ray bursts

    International Nuclear Information System (INIS)

    Japelj, J.; Kopač, D.; Gomboc, A.; Kobayashi, S.; Harrison, R.; Virgili, F. J.; Mundell, C. G.; Guidorzi, C.; Melandri, A.

    2014-01-01

    We use a parent sample of 118 gamma-ray burst (GRB) afterglows, with known redshift and host galaxy extinction, to separate afterglows with and without signatures of dominant reverse-shock (RS) emission and to determine which physical conditions lead to a prominent reverse-shock emission. We identify 10 GRBs with reverse-shock signatures: 990123, 021004, 021211, 060908, 061126, 080319B, 081007, 090102, 090424, and 130427A. By modeling their optical afterglows with reverse- and forward-shock analytic light curves and using Monte Carlo simulations, we estimate the parameter space of the physical quantities describing the ejecta and circumburst medium. We find that physical properties cover a wide parameter space and do not seem to cluster around any preferential values. Comparing the rest-frame optical, X-ray, and high-energy properties of the larger sample of non-RS-dominated GRBs, we show that the early-time (<1 ks) optical spectral luminosity, X-ray afterglow luminosity, and γ-ray energy output of our reverse-shock dominated sample do not differ significantly from the general population at early times. However, the GRBs with dominant reverse-shock emission have fainter than average optical forward-shock emission at late times (>10 ks). We find that GRBs with an identifiable reverse-shock component show a high magnetization parameter R B = ε B,r /ε B,f ∼ 2-10 4 . Our results are in agreement with the mildly magnetized baryonic jet model of GRBs.

  5. Mass spectrometer diagnostic technique in the study of stationary afterglow plasmas in helium, argon and krypton

    International Nuclear Information System (INIS)

    Langenwalter, M.

    1979-01-01

    Since some years the method of massspectrometric monitoring has become an important tool in the analysis of time resolved (or stationary) afterglow plasmas. The present thesis reports the construction and testing of a new fully bakeable UHV-stationary-afterglow-apparatus using a hollow cathode discharge as plasma source for the first time. The hollow cathode is moveable perpendicular to its axis relative to the sampling orifice (i.e. a very small hole at the centre of the plasma container's boundary), so that the radical distribution of the charged particle density can be studied. Several specific extraction conditions for ions from the plasma especially the sampling probe potential have been systematically investigated. Results are illustrated and discussed. The new apparatus has been tested by determining the ambipolar diffusion coefficient of the molecular ion He 2 + in a pure Helium-plasma in thermal equilibrium. The present result (Dsub(a2) = 603 +- 38 / P 0 cm 2 s -1 ) is in agreement with results reported by other workers. Finally an example for the radial behaviour of the Ar + -sampling current in an Argon-discharge for several different times in the afterglow period is given. The shown behaviour agrees relatively well with the theoretically predicted radial ion density distribution, i.e. the zero-order Ressel'function. (Author)

  6. GRB 081029: A Gamma-Ray Burst with a Multi-Component Afterglow

    Science.gov (United States)

    Holland, Stephen T.; DePasquale, Massimiliano; Mao, Jirong; Sakamoto, Taka; Shady, Patricia; Covino, Stefano; Yi-Zhong, Fan; Zhi-Ping, Jin; D'Avanzo, Paolo; Antonelli, Angelo; hide

    2011-01-01

    We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift UltraViolet Optical Telescope with ground-based optical and infrared data obtained using the REM and ROTSE telescopes to construct a detailed data set extending from 86 s to approx. 100000 s after the BAT trigger. Our data cover a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 5000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.

  7. Afterglow Population Studies from Swift Follow-Up Observations of Fermi LAT GRBs

    Science.gov (United States)

    Racusin, Judith L.; Oates, S. R.; McEnery, J.; Vasileiou, V.; Troja, E.; Gehrels, N.

    2010-01-01

    The small population of Fermi LAT detected GRBs discovered over the last year has been providing interesting and unexpected clues into GRB prompt and afterglow emission mechanisms. Over the last 5 years, it has been Swift that has provided the robust data set of UV/optical and X-ray afterglow observations that opened many windows into other components of GRB emission structure. We explore the new ability to utilize both of these observatories to study the same GRBs over 10 orders of magnitude in energy, although not always concurrently. Almost all LAT GRBs that have been followed-up by Swift within 1-day have been clearly detected and carefully observed. We will present the context of the lower-energy afterglows of this special subset of GRBs that has > 100 MeV emission compared to the hundreds in the Swift database that may or may not have been observed by LAT, and theorize upon the relationship between these properties and the origin of the high energy gamma-ray emission.

  8. Preparation and properties of silicone fouling release coatings with long-life afterglow fluorescent

    Directory of Open Access Journals (Sweden)

    Zhang Zhanping

    2017-01-01

    Full Text Available Based on polydimethylsiloxane, three-component coatings were prepared with different content of luminescence powder. The results showed that the illuminance of coatings increases with the content of luminescence powder, decays exponentially with the afterglow time, increases exponentially with the increase of exposure time. The afterglow illuminance augments with irradiated light illuminance. All coatings are hydrophobic and oleophilic. Surface free energy decreases with the increase of luminescence powder. They have highest impact-resistance and bend flexibility. The luminescence powder does not change obviously the shore hardness, tensile breaking strength, breaking elongation rate, elastic modular and roughness of coatings. The static test panels in sea generally could be covered obviously by biofouling including sponges, bryophytes and mussels, hydra, kelp, green algae after 2 months of immersion during growing season. But it never found that the barnacle attached on the coating surface during 4 years of immersion test. The static anti-fouling ability of the coatings is very limited. In addition, the sea creatures attached on the coating surface can be easily removed; even attached organisms will fall off and expose again the smooth coating surface. Consequently, all coatings with long-life afterglow fluorescent have a significant effect on preventing adhesion of barnacle and fouling-release performance.

  9. Novel methods for measuring afterglow in developmental scintillators for X-ray and neutron detection

    Science.gov (United States)

    Bartle, C. M.; Edgar, A.; Dixie, L.; Varoy, C.; Piltz, R.; Buchanan, S.; Rutherford, K.

    2011-09-01

    In this paper we discuss two novel methods of measuring afterglow in scintillators. One method is designed for X-ray detection and the other for neutron detection applications. In the first method a commercial fan-beam scanner of basic design similar to those seen at airports is used to deliver a typically 12 ms long X-ray pulse to a scintillator by passing the test equipment through the scanner on the conveyor belt. In the second method the thermal neutron beam from a research reactor is incident on the scintillator. The beam is cut-off in about 1 ms using a 10B impregnated aluminum pneumatic shutter, and the afterglow is recorded on a dual range storage oscilloscope to capture both the steady state intensity and the weak decay. We describe these measurement methods and the results obtained for a range of developmental ceramic and glass scintillators, as well as some standard scintillators such as NaI(Tl), LiI(Eu) and the plastic scintillator NE102A. Preliminary modeling of the afterglow is presented.

  10. Novel methods for measuring afterglow in developmental scintillators for X-ray and neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Bartle, C.M., E-mail: m.bartle@gns.cri.nz [National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5040 (New Zealand); Edgar, A.; Dixie, L.; Varoy, C. [School of Chemistry and Physics, Victoria University of Wellington, Wellington 6140 (New Zealand); Piltz, R. [Bragg Institute, ANSTO, PMB 1, Menai NSW 2234 (Australia); Buchanan, S.; Rutherford, K. [School of Chemistry and Physics, Victoria University of Wellington, Wellington 6140 (New Zealand)

    2011-09-21

    In this paper we discuss two novel methods of measuring afterglow in scintillators. One method is designed for X-ray detection and the other for neutron detection applications. In the first method a commercial fan-beam scanner of basic design similar to those seen at airports is used to deliver a typically 12 ms long X-ray pulse to a scintillator by passing the test equipment through the scanner on the conveyor belt. In the second method the thermal neutron beam from a research reactor is incident on the scintillator. The beam is cut-off in about 1 ms using a {sup 10}B impregnated aluminum pneumatic shutter, and the afterglow is recorded on a dual range storage oscilloscope to capture both the steady state intensity and the weak decay. We describe these measurement methods and the results obtained for a range of developmental ceramic and glass scintillators, as well as some standard scintillators such as NaI(Tl), LiI(Eu) and the plastic scintillator NE102A. Preliminary modeling of the afterglow is presented.

  11. IMPRINTS OF ELECTRON–POSITRON WINDS ON THE MULTIWAVELENGTH AFTERGLOWS OF GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Geng, J. J.; Huang, Y. F.; Dai, Z. G.; Wu, X. F.; Li, L.

    2016-01-01

    Optical rebrightenings in the afterglows of some gamma-ray bursts (GRBs) are unexpected within the framework of the simple external shock model. While it has been suggested that the central engines of some GRBs are newly born magnetars, we aim to relate the behaviors of magnetars to the optical rebrightenings. A newly born magnetar will lose its rotational energy in the form of Poynting-flux, which may be converted into a wind of electron–positron pairs through some magnetic dissipation processes. As proposed by Dai, this wind will catch up with the GRB outflow and a long-lasting reverse shock (RS) would form. By applying this scenario to GRB afterglows, we find that the RS propagating back into the electron–positron wind can lead to an observable optical rebrightening and a simultaneous X-ray plateau (or X-ray shallow decay). In our study, we select four GRBs (i.e., GRB 080413B, GRB 090426, GRB 091029, and GRB 100814A), of which the optical afterglows are well observed and show clear rebrightenings. We find that they can be well interpreted. In our scenario, the spin-down timescale of the magnetar should be slightly smaller than the peak time of the rebrightening, which can provide a clue to the characteristics of the magnetar.

  12. Multi-Band Light Curves from Two-Dimensional Simulations of Gamma-Ray Burst Afterglows

    Science.gov (United States)

    MacFadyen, Andrew

    2010-01-01

    The dynamics of gamma-ray burst outflows is inherently multi-dimensional. 1.) We present high resolution two-dimensional relativistic hydrodynamics simulations of GRBs in the afterglow phase using adaptive mesh refinement (AMR). Using standard synchrotron radiation models, we compute multi-band light curves, from the radio to X-ray, directly from the 2D hydrodynamics simulation data. We will present on-axis light curves for both constant density and wind media. We will also present off-axis light curves relevant for searches for orphan afterglows. We find that jet breaks are smoothed due to both off-axis viewing and wind media effects. 2.) Non-thermal radiation mechanisms in GRB afterglows require substantial magnetic field strengths. In turbulence driven by shear instabilities in relativistic magnetized gas, we demonstrate that magnetic field is naturally amplified to half a percent of the total energy (epsilon B = 0.005). We will show high resolution three dimensional relativistic MHD simulations of this process as well as particle in cell (PIC) simulations of mildly relativistic collisionless shocks.

  13. Rates of short-GRB afterglows in association with binary neutron star mergers

    Science.gov (United States)

    Saleem, M.; Pai, Archana; Misra, Kuntal; Resmi, L.; Arun, K. G.

    2018-03-01

    Assuming all binary neutron star (BNS) mergers produce short gamma-ray bursts, we combine the merger rates of BNS from population synthesis studies, the sensitivities of advanced gravitational wave (GW) interferometer networks, and of the electromagnetic (EM) facilities in various wavebands, to compute the detection rate of associated afterglows in these bands. Using the inclination angle measured from GWs as a proxy for the viewing angle and assuming a uniform distribution of jet opening angle between 3° and 30°, we generate light curves of the counterparts using the open access afterglow hydrodynamics package BOXFIT for X-ray, optical, and radio bands. For different EM detectors, we obtain the fraction of EM counterparts detectable in these three bands by imposing appropriate detection thresholds. In association with BNS mergers detected by five (three) detector networks of advanced GW interferometers, assuming a BNS merger rate of 0.6-774 Gpc-3 yr-1 from population synthesis models, we find the afterglow detection rates (per year) to be 0.04-53 (0.02-27), 0.03-36 (0.01-19), and 0.04-47 (0.02-25) in the X-ray, optical, and radio bands, respectively. Our rates represent maximum possible detections for the given BNS rate since we ignore effects of cadence and field of view in EM follow-up observations.

  14. Afterglow properties of CaF2:Tm nanoparticles and its potential application in photodynamic therapy

    International Nuclear Information System (INIS)

    Zahedifar, M.; Sadeghi, E.; Shanei, M.M.; Sazgarnia, A.; Mehrabi, M.

    2016-01-01

    CaF 2 :Tm nanoparticles (NPs) were synthesized by the hydrothermal method. Intense afterglow emission with long life time was found for the produced NPs, so its applicability in photodynamic therapy was investigated. Since the wavelength of the afterglow emission of the NPs fairly matches with the absorption band of the PpIX sensitizer, especially in the red region, the Cystein mediator was used to bond NPs with the PpIX sensitizer. The CaF 2 :Tm NPs conjugated with PpIX was exposed to X-ray and by using the Antracene as detector, the production of the singlet oxygen was verified. Therefore, the produced NPs are recommended as a source of energy that improves photodynamic therapy beyond its current limitations. - Highlights: • Intense afterglow emission found for the synthesized CaF 2 :Tm nanoparticles. • CaF 2 :Tm emission band fairly matched with PpIX sensitizer's absorption band. • CaF 2 :Tm conjugated with the sensitized is a good candidate for photodynamic therapy. • The application of nanoparticles in producing singlet oxygen was verified.

  15. Determination of Cosmological Parameters from GRB Correlation between E_iso (gamma) and Afterglow Flux

    Science.gov (United States)

    Hannachi, Zitouni; Guessoum, Nidhal; Azzam, Walid

    2016-07-01

    Context: We use the correlation relations between the energy emitted by the GRBs in their prompt phases and the X-ray afterglow fluxes, in an effort to constrain cosmological parameters and construct a Hubble diagram at high redshifts, i.e. beyond those found in Type Ia supernovae. Methods: We use a sample of 128 Swift GRBs, which we have selected among more than 800 ones observed until July 2015. The selection is based on a few observational constraints: GRB flux higher than 0.4 photons/cm^2/s in the band 15-150 keV; spectrum fitted with simple power law; redshift accurately known and given; and X-ray afterglow observed and flux measured. The statistical method of maximum likelihood is then used to determine the best cosmological parameters (Ω_M, Ω_L) that give the best correlation between the isotropic gamma energies E_{iso} and the afterglow fluxes at the break time t_{b}. The χ^2 statistical test is also used as a way to compare results from two methods. Results & Conclusions: Although the number of GRBs with high redshifts is rather small, and despite the notable dispersion found in the data, the results we have obtained are quite encouraging and promising. The values of the cosmological parameters obtained here are close to those currently used.

  16. GRB 081029: A GAMMA-RAY BURST WITH A MULTI-COMPONENT AFTERGLOW

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Stephen T.; Sakamoto, Takanori [Astrophysics Science Division, Code 660.1, 8800 Greenbelt Road, Goddard Space Flight Centre, Greenbelt, MD 20771 (United States); De Pasquale, Massimiliano; Schady, Patricia [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking RH5 6NT (United Kingdom); Mao, Jirong; Covino, Stefano; Jin, Zhi-Ping; D' Avanzo, Paolo; Chincarini, Guido [INAF-Osservatorio Astronomico di Brera, Via Emilio Bianchi 46, I-23807 Merate (Saint Lucia) (Italy); Fan, Yi-Zhong [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Antonelli, Angelo; D' Elia, Valerio; Fiore, Fabrizio [INAF-Osservatorio Astronomico di Roma, Via de Frascati 33, I-00040 Monteporzio Catone (Roma) (Italy); Pandey, Shashi Bhushan [Randall Laboratory of Physics, University of Michigan, 450 Church St, Ann Arbor, MI 48109-1040 (United States); Cobb, Bethany E., E-mail: Stephen.T.Holland@nasa.gov [Department of Physics, The George Washington University, 725 21st St NW, Washington, DC 20052 (United States)

    2012-01-20

    We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift UltraViolet/Optical Telescope with ground-based optical and infrared data obtained using the REM, ROTSE, and CTIO 1.3 m telescopes to construct a detailed data set extending from 86 s to {approx}100000 s after the BAT trigger. Our data cover a wide energy range from 10 keV to 0.77 eV (1.24 A-16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 3000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray-burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray-burst jets are complex and will require detailed modeling to fully understand them.

  17. Long afterglow property of Er{sup 3+} doped Ca{sub 2}SnO{sub 4} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongyun, E-mail: dyz@sit.edu.cn; Shi, Mingming; Sun, Yiwen; Guo, Yunyun; Chang, Chengkang

    2016-05-15

    A novel green emitting long afterglow phosphor, Er{sup 3+} -doped Ca{sub 2}SnO{sub 4} (Ca{sub 2}SnO{sub 4}:Er{sup 3+}), was prepared successfully via a traditional high temperature solid–state reaction method. Its properties have been characterized and analyzed by utilizing x-ray diffraction (XRD), photoluminescence spectroscope (PLS), afterglow decay curve (ADC) and thermal luminescence spectroscope (TLS). Three main emission peaks of PLS locate at 524, 550 and 668 nm, corresponding to CIE chromaticity coordinates of x = 0.326, y = 0.6592. An optimal doping concentration of Er{sup 3+} of 2% was determined. The Ca{sub 2}SnO{sub 4}:Er{sup 3+} phosphors showed a typical triple-exponential afterglow decay behavior when the UV source was switched off. Thermal simulated luminescence study indicated that the persistent afterglow of Ca{sub 2}SnO{sub 4}:2 mol% Er{sup 3+} phosphors was generated by the suitable electron or hole traps which were resulted from the doping the Ca{sub 2}SnO{sub 4} host with rare-earth ions (Er{sup 3+}). - Highlights: • A novel green emitting long afterglow phosphor, Ca{sub 2}SnO{sub 4}:Er{sup 3+}, was prepared. • An optimal doping concentration of Er{sup 3+} of 2% was determined. • After the UV source was turned off, the Ca{sub 2}SnO{sub 4}:Er{sup 3+} showed a typical triple-exponential afterglow decay behavior. • CIE chromaticity coordinates results confirmed a green light emitting of the Ca{sub 2}SnO{sub 4}:Er{sup 3+}. • The persistent afterglow of the Ca{sub 2}SnO{sub 4}:Er{sup 3+} was attributed to suitable electron or hole traps.

  18. Chemical abundances associated with gamma-ray bursts: nucleosynthesis in afterglows

    Science.gov (United States)

    Hu, Tao; Wang, Min

    2014-03-01

    Gamma-ray burst (GRB) ejecta carries huge amounts of energy expanding into the surrounding medium and heats up these materials, making it possible that nucleosynthesis can take place in such hot sites in afterglow stage. Here, we study possible changes in chemical abundances in the GRB afterglow processes of Wolf-Rayet (WR) star wind environments (Case A) and constant density surroundings (Case B). We find that the light element of lithium-beryllium-boron could occur in the afterglows via He+He process and spallation reactions. Some isotopes of F, Ne, Mg, Al, Si, P, S and Fe-group elements are also new species formed in the afterglows via proton-, neutron- and α-capture. The results show that the nucleosynthetic yields might be a diagnostic of the GRB's ambient environment. Our calculations indicate that Mg, Al, Si, P, Cr, Mn, Fe and Co have trended to appear in Case A, while Ne, Ti and Ni trend to occur in Case B. Furthermore, although some species have occurred both in Cases A and B, their mass fractions are quite different in these two cases. Here, we show that the mass fractions of 7Li, 7Be, 24Mg and 30Si are higher in Case A than that in Case B, but 18F gives an opposite conclusion. Nucleosynthetic outputs might also be an indice to estimate the luminosity-temperature relation factor β. In this study, when β reduces, the mass abundances of 11B and 20Ne are higher in Case B than that in Case A; in contrast, as the β becomes larger, this trend would be reversed; therefore, perhaps we could select the above elements as the indicators to estimate the properties of the surroundings around the GRBs. We also suggest that the spectroscopic observations of a GRB afterglow could only reveal the nucleosynthetic outputs from the interaction site between the GRB jet and its ambient matter, but could not represent the original composition of the pre-GRB surrounding medium.

  19. Spectroscopic Study of Recombination in the Early Afterglow of a Helium Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Stevefelt, J

    1968-02-15

    Some properties of a decaying helium plasma have been studied using time resolved spectroscopy and probe diagnostics. The plasma was produced in a pulsed, repetitive, hot cathode discharge in helium at a pressure 11 torr , and the light emitted in the afterglow of the discharge was measured by means of a spectrometer-photomultiplier combination. Single photoelectrons were counted on a scaler during a preset gate time of each discharge cycle, and after a preset number of cycles recorded on punched tape. The spectrometer was calibrated for absolute intensity measurements of the spectral lines of atomic helium. The overall conductance of the positive column was determined by measuring the voltage difference between two probes inserted into the plasma, passing a very small current pulse between the anode and cathode in the afterglow. Heavier current pulses were used to heat the free electrons selectively, thus providing so-called 'afterglow quenching'. From the measured absolute intensities of the helium lines, the number densities of the excited states of helium were calculated. All levels with principal quantum number n {>=} 8 were found to be in near Saha equilibrium with the free electrons at a temperature 1,275 deg K in the early afterglow (15-35 {mu}s after end of the discharge). By measuring the absolute intensities of some of the molecular helium bands, an estimate of the rate of conversion of atomic helium ions into molecular helium ions was obtained. The atomic line radiation, as well as the molecular band radiation, was assumed to result from collisional-radiative recombination of atomic and molecular helium ions, respectively. The rate of recombination down to the metastable level n = 2 was obtained from the measured line intensities. By adding the rate of ambipolar diffusion, calculated from known literature data, quite good agreement with the measured decay rate for the electron density was found. The measured line intensities were also used to calculate

  20. DISCOVERY OF THE VERY RED NEAR-INFRARED AND OPTICAL AFTERGLOW OF THE SHORT-DURATION GRB 070724A

    International Nuclear Information System (INIS)

    Berger, E.; Cenko, S. B.; Fox, D. B.; Cucchiara, A.

    2009-01-01

    We report the discovery of the near-infrared and optical afterglow of the short-duration gamma-ray burst GRB 070724A. The afterglow is detected in iJHK s observations starting 2.3 hr after the burst with K s = 19.59 ± 0.16 mag and i = 23.79 ± 0.07 mag, but is absent in images obtained 1.3 yr later. Fading is also detected in the K s band between 2.8 and 3.7 hr at a 4σ significance level. The optical/near-IR spectral index, β O,NIR ∼ -2, is much redder than expected in the standard afterglow model, pointing to either significant dust extinction, A host V ∼ 2 mag, or a non-afterglow origin for the near-IR emission. The case for extinction is supported by a shallow optical to X-ray spectral index, consistent with the definition for 'dark bursts', and a normal near-IR to X-ray spectral index. Moreover, a comparison to the optical discovery magnitudes of all short GRBs with optical afterglows indicates that the near-IR counterpart of GRB 070724A is one of the brightest to date, while its observed optical emission is one of the faintest. In the context of a non-afterglow origin, the near-IR emission may be dominated by a mini-supernova (mini-SN), leading to an estimated ejected mass of M ∼ 10 -4 M sun and a radioactive energy release efficiency of f ∼ 5 x 10 -3 (for v ∼ 0.3c). However, the mini-SN model predicts a spectral peak in the UV rather than near-IR, suggesting that this is either not the correct interpretation or that the mini-SN models need to be revised. Finally, the afterglow coincides with a star-forming galaxy at z = 0.457, previously identified as the host based on its coincidence with the X-ray afterglow position (∼2'' radius). Our discovery of the optical/near-IR afterglow makes this association secure, and furthermore localizes the burst to the outskirts of the galaxy, with an offset of 4.8 ± 0.1 kpc relative to the host center. At such a large offset, the possible large extinction points to a dusty environment local to the burst and

  1. On the non-existence of a sharp cooling break in gamma-ray burst afterglow spectra

    International Nuclear Information System (INIS)

    Uhm, Z. Lucas; Zhang, Bing

    2014-01-01

    Although the widely used analytical afterglow model of gamma-ray bursts (GRBs) predicts a sharp cooling break ν c in its afterglow spectrum, the GRB observations so far rarely show clear evidence for a cooling break in their spectra or a corresponding temporal break in their light curves. Employing a Lagrangian description of the blast wave, we conduct a sophisticated calculation of the afterglow emission. We precisely follow the cooling history of non-thermal electrons accelerated into each Lagrangian shell. We show that a detailed calculation of afterglow spectra does not in fact give rise to a sharp cooling break at ν c . Instead, it displays a very mild and smooth transition, which occurs gradually over a few orders of magnitude in energy or frequency. The main source of this slow transition is that different mini shells have different evolutionary histories of the comoving magnetic field strength B, so that deriving the current value of ν c of each mini shell requires an integration of its cooling rate over the time elapsed since its creation. We present the time evolution of optical and X-ray spectral indices to demonstrate the slow transition of spectral regimes and discuss the implications of our result in interpreting GRB afterglow data.

  2. GRB 081029: A Gamma-Ray Burst with a Multi-Component Afterglow

    Science.gov (United States)

    Holland, Stephen T.; De Pasquale, Massimiliano; Mao, Jirong; Sakamoto, Takanori; Schady, Patricia; Covino, Stefano; Fan, Yi-Zhong; Jin, Zhi-Ping; D'Avanzo, Paolo; Antonelli, Angelo; hide

    2012-01-01

    We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift Ultra Violet/Optical Telescope with ground-based optical and infrared data obtained using the REM, ROTSE, and CTIO 1.3-m telescopes to construct a detailed data set extending from 86 s to approx.100,000 s after the BAT trigger. Our data covers a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18,000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 3000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.injection

  3. The Supercritical Pile Gamma-Ray Burst Model: The GRB Afterglow Steep Decline and Plateau Phase

    Science.gov (United States)

    Sultana, Joseph; Kazanas, D.; Mastichiadis, A.

    2013-01-01

    We present a process that accounts for the steep decline and plateau phase of the Swift X-Ray Telescope (XRT) light curves, vexing features of gamma-ray burst (GRB) phenomenology. This process is an integral part of the "supercritical pile" GRB model, proposed a few years ago to account for the conversion of the GRB kinetic energy into radiation with a spectral peak at E(sub pk) is approx. m(sub e)C(exp 2). We compute the evolution of the relativistic blast wave (RBW) Lorentz factor Gamma to show that the radiation-reaction force due to the GRB emission can produce an abrupt, small (approx. 25%) decrease in Gamma at a radius that is smaller (depending on conditions) than the deceleration radius R(sub D). Because of this reduction, the kinematic criticality criterion of the "supercritical pile" is no longer fulfilled. Transfer of the proton energy into electrons ceases and the GRB enters abruptly the afterglow phase at a luminosity smaller by approx. m(sub p)/m(sub e) than that of the prompt emission. If the radius at which this slow-down occurs is significantly smaller than R(sub D), the RBW internal energy continues to drive the RBW expansion at a constant (new) Gamma and its X-ray luminosity remains constant until R(sub D) is reached, at which point it resumes its more conventional decay, thereby completing the "unexpected" XRT light curve phase. If this transition occurs at R is approx. equal to R(sub D), the steep decline is followed by a flux decrease instead of a "plateau," consistent with the conventional afterglow declines. Besides providing an account of these peculiarities, the model suggests that the afterglow phase may in fact begin before the RBW reaches R is approx. equal to R(sub D), thus providing novel insights into GRB phenomenology.

  4. A CORRELATED STUDY OF OPTICAL AND X-RAY AFTERGLOWS OF GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liang; Ryde, Felix [Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm (Sweden); Wu, Xue-Feng [Chinese Center for Antarctic Astronomy, Chinese Academy of Sciences, Nanjing 210008 (China); Huang, Yong-Feng; Tang, Qing-Wen; Geng, Jin-Jun [Department of Astronomy, Nanjing University, Nanjing 210093, Jiangsu (China); Wang, Xiang-Gao; Liang, En-Wei [GXU-NAOC Center for Astrophysics and Space Sciences, Department of Physics, Guangxi University, Nanjing 530004 (China); Liang, Yun-Feng [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang, Bin-Bin [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Wang, Yu [Dip. di Fisica and ICRA, Sapienza Universit di Roma, Piazzale Aldo Moro 5, I-00185 Rome (Italy); Wei, Jian-Yan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Zhang, Bing, E-mail: fryde@kth.se, E-mail: liang.li@fysik.su.se [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2015-05-20

    We study an extensive sample of 87 gamma-ray bursts (GRBs) for which there are well-sampled and simultaneous optical and X-ray light curves. We extract the cleanest possible signal of the afterglow component and compare the temporal behaviors of the X-ray light curve, observed by Swift XRT, and optical data, observed by UVOT and ground-based telescopes for each individual burst. Overall we find that 62% of the GRBs are consistent with the standard afterglow model. When more advanced modeling is invoked, up to 91% of the bursts in our sample may be consistent with the external-shock model. A large fraction of these bursts are consistent with occurring in a constant interstellar density medium (61%) while only 39% of them occur in a wind-like medium. Only nine cases have afterglow light curves that exactly match the standard fireball model prediction, having a single power-law decay in both energy bands that are observed during their entire duration. In particular, for the bursts with chromatic behavior, additional model assumptions must be made over limited segments of the light curves in order for these bursts to fully agree with the external-shock model. Interestingly, for 54% of the X-ray and 40% of the optical band observations, the end of the shallow decay (t{sup ∼−0.5}) period coincides with the jet-break (t{sup ∼−p}) time, causing an abrupt change in decay slope. The fraction of the burst that is consistent with the external-shock model is independent of the observational epochs in the rest frame of GRBs. Moreover, no cases can be explained by the cooling frequency crossing the X-ray or optical band.

  5. GRB 090926A AND BRIGHT LATE-TIME FERMI LARGE AREA TELESCOPE GAMMA-RAY BURST AFTERGLOWS

    International Nuclear Information System (INIS)

    Swenson, C. A.; Roming, P. W. A.; Vetere, L.; Kennea, J. A.; Maxham, A.; Zhang, B. B.; Zhang, B.; Schady, P.; Holland, S. T.; Kuin, N. P. M.; Oates, S. R.; De Pasquale, M.; Page, K. L.

    2010-01-01

    GRB 090926A was detected by both the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. Swift follow-up observations began ∼13 hr after the initial trigger. The optical afterglow was detected for nearly 23 days post trigger, placing it in the long-lived category. The afterglow is of particular interest due to its brightness at late times, as well as the presence of optical flares at T0+10 5 s and later, which may indicate late-time central engine activity. The LAT has detected a total of 16 gamma-ray bursts; nine of these bursts, including GRB 090926A, also have been observed by Swift. Of the nine Swift-observed LAT bursts, six were detected by UVOT, with five of the bursts having bright, long-lived optical afterglows. In comparison, Swift has been operating for five years and has detected nearly 500 bursts, but has only seen ∼30% of bursts with optical afterglows that live longer than 10 5 s. We have calculated the predicted gamma-ray fluence, as would have been seen by the Burst Alert Telescope (BAT) on board Swift, of the LAT bursts to determine whether this high percentage of long-lived optical afterglows is unique, when compared to BAT-triggered bursts. We find that, with the exception of the short burst GRB 090510A, the predicted BAT fluences indicate that the LAT bursts are more energetic than 88% of all Swift bursts and also have brighter than average X-ray and optical afterglows.

  6. DISCOVERY AND REDSHIFT OF AN OPTICAL AFTERGLOW IN 71 deg2: iPTF13bxl AND GRB 130702A

    International Nuclear Information System (INIS)

    Singer, Leo P.; Brown, Duncan A.; Bradley Cenko, S.; Gehrels, Neil; McEnery, Julie; Kasliwal, Mansi M.; Mulchaey, John; Perley, Daniel A.; Kulkarni, S. R.; Bellm, Eric; Barlow, Tom; Cao, Yi; Horesh, Assaf; Ofek, Eran O.; Arcavi, Iair; Nugent, Peter E.; Bloom, Joshua S.; Corsi, Alessandra; Frail, Dale A.; Masci, Frank J.

    2013-01-01

    We report the discovery of the optical afterglow of the γ-ray burst (GRB) 130702A, identified upon searching 71 deg 2 surrounding the Fermi Gamma-ray Burst Monitor (GBM) localization. Discovered and characterized by the intermediate Palomar Transient Factory, iPTF13bxl is the first afterglow discovered solely based on a GBM localization. Real-time image subtraction, machine learning, human vetting, and rapid response multi-wavelength follow-up enabled us to quickly narrow a list of 27,004 optical transient candidates to a single afterglow-like source. Detection of a new, fading X-ray source by Swift and a radio counterpart by CARMA and the Very Large Array confirmed the association between iPTF13bxl and GRB 130702A. Spectroscopy with the Magellan and Palomar 200 inch telescopes showed the afterglow to be at a redshift of z = 0.145, placing GRB 130702A among the lowest redshift GRBs detected to date. The prompt γ-ray energy release and afterglow luminosity are intermediate between typical cosmological GRBs and nearby sub-luminous events such as GRB 980425 and GRB 060218. The bright afterglow and emerging supernova offer an opportunity for extensive panchromatic follow-up. Our discovery of iPTF13bxl demonstrates the first observational proof-of-principle for ∼10 Fermi-iPTF localizations annually. Furthermore, it represents an important step toward overcoming the challenges inherent in uncovering faint optical counterparts to comparably localized gravitational wave events in the Advanced LIGO and Virgo era

  7. THE AFTERGLOW AND ULIRG HOST GALAXY OF THE DARK SHORT GRB 120804A

    International Nuclear Information System (INIS)

    Berger, E.; Zauderer, B. A.; Margutti, R.; Laskar, T.; Fong, W.; Chornock, R.; Dupuy, T. J.; Levan, A.; Tunnicliffe, R. L.; Mangano, V.; Fox, D. B.; Tanvir, N. R.; Menten, K. M.; Hjorth, J.; Roth, K.

    2013-01-01

    We present the optical discovery and subarcsecond optical and X-ray localization of the afterglow of the short GRB 120804A, as well as optical, near-IR, and radio detections of its host galaxy. X-ray observations with Swift/XRT, Chandra, and XMM-Newton extending to δt ≈ 19 days reveal a single power-law decline. The optical afterglow is faint, and comparison to the X-ray flux indicates that GRB 120804A is ''dark'', with a rest-frame extinction of A host V ≈ 2.5 mag (at z = 1.3). The intrinsic neutral hydrogen column density inferred from the X-ray spectrum, N H, i nt (z = 1.3) ≈ 2 × 10 22 cm –2 , is commensurate with the large extinction. The host galaxy exhibits red optical/near-IR colors. Equally important, JVLA observations at ≈0.9-11 days reveal a constant flux density of F ν (5.8 GHz) = 35 ± 4 μJy and an optically thin spectrum, unprecedented for GRB afterglows, but suggestive instead of emission from the host galaxy. The optical/near-IR and radio fluxes are well fit with the scaled spectral energy distribution of the local ultraluminous infrared galaxy (ULIRG) Arp 220 at z ≈ 1.3, with a resulting star formation rate of x ≈ 300 M ☉ yr –1 . The inferred extinction and small projected offset (2.2 ± 1.2 kpc) are also consistent with the ULIRG scenario, as is the presence of a companion galaxy at the same redshift and with a separation of about 11 kpc. The limits on radio afterglow emission, in conjunction with the observed X-ray and optical emission, require a circumburst density of n ∼ 10 –3 cm –3 , an isotropic-equivalent energy scale of E γ, i so ≈ E K, i so ≈ 7 × 10 51 erg, and a jet opening angle of θ j ∼> 11°. The expected fraction of luminous infrared galaxies in the short GRB host sample is ∼0.01 and ∼0.25 (for pure stellar mass and star formation weighting, respectively). Thus, the observed fraction of two events in about 25 hosts (GRBs 120804A and 100206A) appears to support our previous conclusion that short

  8. Recombination of KrD+ and KrH+ ions in afterglow plasma

    International Nuclear Information System (INIS)

    Korolov, I; Kotrik, T; Plasil, R; Hejduk, M; Varju, J; Dohnal, P; Glosik, J

    2009-01-01

    Reported is flowing afterglow (FALP) study of recombination of KrH + and KrD + ions with electrons at 250 K in mixtures of He/Kr/H 2 and He/Kr/D 2 , respectively. The influence of fast recombining cluster ions formation on apparent effective recombination rate coefficients (α eff ) was measured and used in data analysis. The obtained binary rate coefficients for recombination of KrH + and KrD + are α KrH+ = 2x10 -8 cm 3 s -1 and α KrD+ = 1x10 -8 cm 3 s -1 .

  9. Recombination of KrD+ and KrH+ ions in afterglow plasma

    Science.gov (United States)

    Korolov, I.; Kotrik, T.; Plasil, R.; Hejduk, M.; Varju, J.; Dohnal, P.; Glosik, J.

    2009-11-01

    Reported is flowing afterglow (FALP) study of recombination of KrH+ and KrD+ ions with electrons at 250 K in mixtures of He/Kr/H2 and He/Kr/D2, respectively. The influence of fast recombining cluster ions formation on apparent effective recombination rate coefficients (αeff) was measured and used in data analysis. The obtained binary rate coefficients for recombination of KrH+ and KrD+ are αKrH+ = 2×10-8 cm3s-1 and αKrD+ = 1×10-8 cm3s-1.

  10. X-ray spectral components observed in the afterglow of GRB 130925A

    DEFF Research Database (Denmark)

    Bellm, Eric C.; Barrière, Nicolas M.; Bhalerao, Varun

    2014-01-01

    We have identified spectral features in the late-time X-ray afterglow of the unusually long, slow-decaying GRB 130925A using NuSTAR, Swift/X-Ray Telescope, and Chandra. A spectral component in addition to an absorbed power law is required at >4σ significance, and its spectral shape varies between...... two observation epochs at 2 × 105 and 106 s after the burst. Several models can fit this additional component, each with very different physical implications. A broad, resolved Gaussian absorption feature of several keV width improves the fit, but it is poorly constrained in the second epoch...

  11. Nitric oxide kinetics in the afterglow of a diffuse plasma filament

    International Nuclear Information System (INIS)

    Burnette, D; Montello, A; Adamovich, I V; Lempert, W R

    2014-01-01

    A suite of laser diagnostics is used to study kinetics of vibrational energy transfer and plasma chemical reactions in a nanosecond pulse, diffuse filament electric discharge and afterglow in N 2 and dry air at 100 Torr. Laser-induced fluorescence of NO and two-photon absorption laser-induced fluorescence of O and N atoms are used to measure absolute, time-resolved number densities of these species after the discharge pulse, and picosecond coherent anti-Stokes Raman spectroscopy is used to measure time-resolved rotational temperature and ground electronic state N 2 (v = 0–4) vibrational level populations. The plasma filament diameter, determined from plasma emission and NO planar laser-induced fluorescence images, remains nearly constant after the discharge pulse, over a few hundred microseconds, and does not exhibit expansion on microsecond time scale. Peak temperature in the discharge and the afterglow is low, T ≈ 370 K, in spite of significant vibrational nonequilibrium, with peak N 2 vibrational temperature of T v  ≈ 2000 K. Significant vibrational temperature rise in the afterglow is likely caused by the downward N 2 –N 2 vibration–vibration (V–V) energy transfer. Simple kinetic modeling of time-resolved N, O, and NO number densities in the afterglow, on the time scale longer compared to relaxation and quenching time of excited species generated in the plasma, is in good agreement with the data. In nitrogen, the N atom density after the discharge pulse is controlled by three-body recombination and radial diffusion. In air, N, NO and O concentrations are dominated by the reverse Zel'dovich reaction, N + NO → N 2  + O, and ozone formation reaction, O + O 2  + M → O 3  + M, respectively. The effect of vibrationally excited nitrogen molecules and excited N atoms on NO formation kinetics is estimated to be negligible. The results suggest that NO formation in the nanosecond pulse discharge is dominated by reactions of

  12. Nitric oxide kinetics in the afterglow of a diffuse plasma filament

    Science.gov (United States)

    Burnette, D.; Montello, A.; Adamovich, I. V.; Lempert, W. R.

    2014-08-01

    A suite of laser diagnostics is used to study kinetics of vibrational energy transfer and plasma chemical reactions in a nanosecond pulse, diffuse filament electric discharge and afterglow in N2 and dry air at 100 Torr. Laser-induced fluorescence of NO and two-photon absorption laser-induced fluorescence of O and N atoms are used to measure absolute, time-resolved number densities of these species after the discharge pulse, and picosecond coherent anti-Stokes Raman spectroscopy is used to measure time-resolved rotational temperature and ground electronic state N2(v = 0-4) vibrational level populations. The plasma filament diameter, determined from plasma emission and NO planar laser-induced fluorescence images, remains nearly constant after the discharge pulse, over a few hundred microseconds, and does not exhibit expansion on microsecond time scale. Peak temperature in the discharge and the afterglow is low, T ≈ 370 K, in spite of significant vibrational nonequilibrium, with peak N2 vibrational temperature of Tv ≈ 2000 K. Significant vibrational temperature rise in the afterglow is likely caused by the downward N2-N2 vibration-vibration (V-V) energy transfer. Simple kinetic modeling of time-resolved N, O, and NO number densities in the afterglow, on the time scale longer compared to relaxation and quenching time of excited species generated in the plasma, is in good agreement with the data. In nitrogen, the N atom density after the discharge pulse is controlled by three-body recombination and radial diffusion. In air, N, NO and O concentrations are dominated by the reverse Zel'dovich reaction, N + NO → N2 + O, and ozone formation reaction, O + O2 + M → O3 + M, respectively. The effect of vibrationally excited nitrogen molecules and excited N atoms on NO formation kinetics is estimated to be negligible. The results suggest that NO formation in the nanosecond pulse discharge is dominated by reactions of excited electronic states of nitrogen, occurring on

  13. Construction of automatic photographic system for after-glow colour images (AGCI)

    International Nuclear Information System (INIS)

    Kawamura, Kousei; Hashimoto, Tetsuo.

    1995-01-01

    An automatic photographic system of the after-glow colour images (AGCI), which give very useful information related to crystal defects and impurities in white inorganic materials, has been developed. The present system consists of a combination of a photographic part installed in a dark bag with a control personal computer through an interface board. Thus, the photographic procedure of the successive and clear AGCIs could be accomplished from the direct contact of a colour film with an X-rays irradiated rock slices for desired exposure periods and interval times. By using this system, some AGCIs of ammonite fossil showed interesting changes of orange patterns due to structural fossil calcite. (author)

  14. Dynamics of excited nitrogen molecular states in glow- and afterglow phases of discharge: experiment and modeling

    International Nuclear Information System (INIS)

    Napartovich, A.P.; Akishev, Yu.S.; Dyatko, N.A.; Grushin, M.E.; Filippov, A.V.; Trushkin, N.I.

    2001-01-01

    Population dynamics for a number of levels from N2 ( A 3 Σ + u ), N 2 (B 3 Π g ) and N 2 (C 3 Π u ) manifolds was studied spectroscopically in a long pulse glow discharge in pure nitrogen and in afterglow at pressure 50 Torr. Overshot in time behaviour of N 2 (A 3Σ + u ), N 2 (B 3 Π g ) and N 2 (C 3 Π u ) levels populations was revealed. A rather complete kinetic model is developed for conditions of the experiments. Results of comparison are analyzed

  15. Implications from the upper limit of radio afterglow emission of FRB 131104/Swift J0644.5-5111

    OpenAIRE

    Gao, He; Zhang, Bing

    2016-01-01

    A $\\gamma$-ray transient, Swift J0644.5-5111, has been claimed to be associated with FRB 131104. The $\\gamma$-ray energy output is estimated as $E_\\gamma \\approx 5\\times 10^{51}$\\,erg at the nominal $z\\approx 0.55$ redshift implied by the dispersion measure of FRB 131104. However, a long-term radio imaging follow-up observations only place an upper limit on the radio afterglow flux of Swift J0644.5-5111. Applying the external shock model, we make a detailed constraint on the afterglow paramet...

  16. VLT identification of the optical afterglow of the gamma-ray burst GRB000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M.I.; Hjorth, J.; Jesen, B.L.

    2000-01-01

    We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve...

  17. VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M.I.; Hjorth, J.; Pedersen, H.

    2000-01-01

    We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve...

  18. Extinction of gamma-ray burst afterglows as a diagnostic of the location of cosmic star formation

    Science.gov (United States)

    Ramirez-Ruiz, Enrico; Trentham, Neil; Blain, A. W.

    2002-01-01

    The properties of gamma-ray bursts (GRBs) and their afterglows are used to investigate the location of star formation activity through the history of the Universe. This approach is motivated by the following: (i) GRBs are thought to be associated with the deaths of massive stars and so the GRB rate ought to follow the formation rate of massive stars; (ii) GRBs are the last phase of the evolution of these stars, which do not live long enough to travel far from their place of birth, and so GRBs are located where the stars formed; and (iii) GRB afterglows occur over both X-ray and optical wavelengths, and so the differential effects of dust extinction between the two wavebands can reveal whether or not large amounts of dust are present in galaxies hosting GRBs. Recent evidence suggests that a significant fraction of stars in the Universe formed in galaxies that are bright at rest-frame submillimetre (submm) and infrared wavelengths rather than at ultraviolet wavelengths; we estimate about three quarters of the star formation in the Universe occurred in the submm-bright mode. High-redshift submm-selected galaxies are thought to have properties similar to local ultraluminous infrared galaxies (ULIGs) such as Arp 220, based on the concordance between their luminosities and spectral energy distributions. If this is the case, then GRBs in submm-bright galaxies should have their optical afterglows extinguished by internal dust absorption, but only very few should have their 2-10keV X-ray afterglows obscured. The value that we quote of three quarters is marginally consistent with observations of GRBs: 60+/-15 per cent of GRBs have no detected optical afterglow, whereas almost all have an X-ray afterglow. A more definitive statement could be made with observations of soft X-ray afterglows (0.5-2keV), in which extinction should be severe for GRBs located in submm-bright galaxies with gas densities similar to those in local ULIGs. If the X-ray afterglows disappear at soft X

  19. The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724.

    Science.gov (United States)

    Berger, E; Price, P A; Cenko, S B; Gal-Yam, A; Soderberg, A M; Kasliwal, M; Leonard, D C; Cameron, P B; Frail, D A; Kulkarni, S R; Murphy, D C; Krzeminski, W; Piran, T; Lee, B L; Roth, K C; Moon, D-S; Fox, D B; Harrison, F A; Persson, S E; Schmidt, B P; Penprase, B E; Rich, J; Peterson, B A; Cowie, L L

    2005-12-15

    Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness--the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

  20. On the X-ray lines in the afterglows of GRBs

    CERN Document Server

    Dar, Arnon; De Rújula, Alvaro; Dar, Arnon; Dado, Shlomo

    2003-01-01

    The observation of X-ray lines in the afterglow of GRB 011211 has been reported, and challenged. The lines were interpreted as blue-shifted X-rays characteristic of a set of photoionized ``metals'', located in a section of a supernova shell illuminated by a GRB emitted a couple of days after the supernova explosion. We show that the most prominent reported lines coincide with the ones predicted in the ``cannonball'' model of GRBs. In this model, the putative signatures are Hydrogen lines, boosted by the (highly relativistic) motion of the cannonballs (CBs). The corresponding Doppler boost can be extracted from the fit to the observed I-, R- and V-band light-curves of the optical afterglow of GRB 011211, so that, since the redshift is also known, the line energies are --in the CB model-- absolute predictions. We also discuss other GRBs of known redshift which show spectral features generally interpreted as Fe lines, or Fe recombination edges. The ensemble of results is very encouraging from the CB-model's poin...

  1. Very Strong TeV Emission as $\\gamma$-Ray Burst Afterglows

    CERN Document Server

    Totani, T

    1998-01-01

    Gamma-ray bursts (GRBs) and following afterglows are considered to be produced by dissipation of kinetic energy of a relativistic fireball and radiation process is widely believed as synchrotron radiation or inverse Compton scattering of electrons. We argue that the transfer of kinetic energy of ejecta into electrons may be inefficient process and hence the total energy released by a GRB event is much larger than that emitted in soft gamma-rays, by a factor of \\sim (m_p/m_e). We show that, in this case, very strong emission of TeV gamma-rays is possible due to synchrotron radiation of protons accelerated up to \\sim 10^{21} eV, which are trapped in the magnetic field of afterglow shock and radiate their energy on an observational time scale of \\sim day. This suggests a possibility that GRBs are most energetic in TeV range and such TeV gamma-rays may be detectable from GRBs even at cosmological distances, i.e., z gives a quantitative explanation for the famous long-duration GeV photons detected from GRB940217. ...

  2. The redshift and afterglow of the extremely energetic gamma-ray burst GRB 080916C

    CERN Document Server

    Greiner, J.; Kruehler, T.; Kienlin, A.v.; Rau, A.; Sari, R.; Fox, Derek B.; Kawai, N.; Afonso, P.; Ajello, M.; Berger, E.; Cenko, S.B.; Cucchiara, A.; Filgas, R.; Klose, S.; Yoldas, A.Kuepue; Lichti, G.G.; Loew, S.; McBreen, S.; Nagayama, T.; Rossi, A.; Sato, S.; Szokoly, G.; Yoldas, A.; Zhang, X.-L.

    2009-01-01

    The detection of GeV photons from gamma-ray bursts (GRBs) has important consequences for the interpretation and modelling of these most-energetic cosmological explosions. The full exploitation of the high-energy measurements relies, however, on the accurate knowledge of the distance to the events. Here we report on the discovery of the afterglow and subsequent redshift determination of GRB 080916C, the first GRB detected by the Fermi Gamma-Ray Space Telescope with high significance detection of photons at >0.1 GeV. Observations were done with 7-channel imager GROND at the 2.2m MPI/ESO telescope, the SIRIUS instrument at the Nagoya-SAAO 1.4m telescope in South Africa, and the GMOS instrument at Gemini-S. The afterglow photometric redshift of z=4.35+-0.15, based on simultaneous 7-filter observations with the Gamma-Ray Optical and Near-infrared Detector (GROND), places GRB 080916C among the top 5% most distant GRBs, and makes it the most energetic GRB known to date. The detection of GeV photons from such a dista...

  3. Metastable atomic species in the N{sub 2} flowing afterglow

    Energy Technology Data Exchange (ETDEWEB)

    Levaton, J. [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol - CTBE/CNPEM, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Amorim, J., E-mail: jayr.amorim@bioetanol.org.br [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol - CTBE/CNPEM, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil)

    2012-03-13

    Graphical abstract: Calculated N({sup 4}S), N({sup 2}D) and N({sup 2}P) absolute densities as a function of the afterglow time. Highlights: Black-Right-Pointing-Pointer Nitrogen flowing post-discharge. Black-Right-Pointing-Pointer N({sup 4}S) and N({sup 2}D) densities. Black-Right-Pointing-Pointer Kinetic numerical model of the nitrogen afterglow. - Abstract: We have studied by optical emission spectroscopy the post-discharge of a pure N{sub 2} DC flowing discharge in such experimental conditions that the pink afterglow and the Lewis-Rayleigh afterglow occur. The emission profiles originated from the N{sub 2}(B{sup 3}{Pi}{sub g}), N{sub 2}(C{sup 3}{Pi}{sub u}) and N{sub 2}{sup +}(B{sup 2}{Sigma}{sub u}{sup +}) states and the N{sub 2}(B{sup 3}{Pi}{sub g},6{<=}v{<=}12) and N{sub 2}(C{sup 3}{Pi}{sub u},0{<=}v{<=}4) vibrational distributions were obtained in the post-discharge region. With basis on the works of Bockel et al. [S. Bockel, A.M. Diamy, A. Ricard, Surf. Coat. Tech. 74 (1995) 474] and Amorim and Kiohara [J. Amorim, V. Kiohara, Chem. Phys. Lett. 385 (2004) 268], we have obtained the experimental N({sup 4}S) and N({sup 2}D) relative densities along the post-discharge. A numerical model, previously developed to describe the neutral atomic, molecular and ionic species in the afterglow, was improved to include the kinetics of N({sup 2}D) and N({sup 2}P) states. Several kinetic mechanisms leading to the production of N({sup 2}D) in the post-discharge have been studied in order to explain the experimental data. We have determined that the dominant one is the reaction N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +},v>8)+N({sup 4}S){yields}N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +})+N({sup 2}D) with an estimated rate constant of 7 Multiplication-Sign 10{sup -14} cm{sup 3} s{sup -1}. Also, the fit of the numerical density profiles of N{sub 2}(C{sup 3}{Pi}{sub u}) and N{sub 2}{sup +}(B{sup 2}{Sigma}{sub u}{sup +}) to the experimental ones has provided the rate constant for reaction

  4. The Growth, Polarization, and Motion of the Radio Afterglow from the Giant Flare from SGR 1806-20

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G

    2005-04-20

    The extraordinary giant flare (GF) of 2004 December 27 from the soft gamma repeater (SGR) 1806-20 was followed by a bright radio afterglow. We present an analysis of VLA observations of this radio afterglow from SGR1806-20, consisting of previously reported 8.5 GHz data covering days 7 to 20 after the GF, plus new observations at 8.5 and 22 GHz from day 24 to 81. For a symmetric outflow, we find a deceleration in the expansion, from {approx}4.5 mas/day to <2.5 mas/day. The time of deceleration is roughly coincident with the rebrightening in the radio light curve, as expected to result when the ejecta from the GF sweeps up enough of the external medium, and transitions from a coasting phase to the Sedov-Taylor regime. The radio afterglow is elongated and maintains a 2:1 axis ratio with an average position angle of -40{sup o} (north through east), oriented perpendicular to the average intrinsic linear polarization angle. We also report on the discovery of motion in the flux centroid of the afterglow, at an average velocity of 0.26 {+-} 0.03 c (assuming a distance of 15 kpc) at a position angle of -45{sup o}. This motion, in combination with the growth and polarization measurements, suggests an initially asymmetric outflow, mainly from one side of the magnetar.

  5. CsI:Tl.sup.+./sup.,Yb.sup.2+./sup.: ultra-high light yield scintillator with reduced afterglow

    Czech Academy of Sciences Publication Activity Database

    Wu, Y.; Ren, G.; Nikl, Martin; Chen, X.; Ding, D.; Li, H.; Pan, S.; Yang, F.

    2014-01-01

    Roč. 16, č. 16 (2014), s. 3312-3317 ISSN 1466-8033 R&D Projects: GA MŠk LH12185 Institutional support: RVO:68378271 Keywords : scintillator * CsI:Tb, Yb codoping * afterglow Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.034, year: 2014

  6. Production of Highly Charged Heavy Ions by Means of a Hybrid Source in DC Mode and in Afterglow Mode

    Czech Academy of Sciences Publication Activity Database

    Gammino, S.; Ciavola, G.; Torrisi, L.; Celona, L.; Andó, L.; Manciagli, S.; Consoli, F.; Galatá, A.; Picciotto, A.; Mezzasalma, A. M.; Krása, Josef; Láska, Leoš; Pfeifer, Miroslav; Rohlena, Karel; Wolowski, J.; Woryna, E.; Parys, P.; Shirkov, G. D.; Hitz, D.

    2005-01-01

    Roč. 2, č. 6 (2005), s. 458-463 ISSN 1612-8850 R&D Projects: GA MŠk(CZ) ME 238 Institutional research plan: CEZ:AV0Z10100523 Keywords : afterglow plasma processes * electron cyclotron resonance (ECR) * ion beams * laser ablation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.846, year: 2005

  7. Diagnostic of N2(A) concentration in high velocity nitrogen afterglow at atmospheric pressure

    Science.gov (United States)

    Pointu, Anne-Marie; Mintusov, Evgeny

    2009-10-01

    An optical emission diagnostic was used to measure N2(A) concentration in a high velocity (1000 cm/s) N2 flowing afterglow of corona discharge at atmospheric pressure, used for biological decontamination. Introducing impurities of NO (measured at different axial distances and for different values of NO injected flow. Moreover, it has been demonstrated that N2(A) creation comes from N+N+N2 atom recombination with a global rate around 2e-33 cm^6/s, a result which agrees with literature, as well as N2(A) loss mechanisms were confirmed to go via quenching with O and N atoms. The order of magnitude of obtained N2(A) concentration, about 1e11 cm-3, coincides with the results of direct measurement (by Vegard-Kaplan band), using a spectrometer of better resolution.

  8. MODELING THE EARLY AFTERGLOW IN THE SHORT AND HARD GRB 090510

    Energy Technology Data Exchange (ETDEWEB)

    Fraija, N.; Lee, W. H. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, Cd. Universitaria, 04510 Ciudad de México, DF (Mexico); Veres, P. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Duran, R. Barniol, E-mail: nifraija@astro.unam.mx, E-mail: wlee@astro.unam.mx, E-mail: pv0004@uah.edu, E-mail: rbarniol@purdue.edu [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

    2016-11-01

    The bright, short, and hard GRB 090510 was detected by all instruments aboard the Fermi and Swift satellites. The multiwavelength observations of this burst presented similar features to the Fermi -LAT-detected gamma-ray bursts. In the framework of the external shock model of early afterglow, a leptonic scenario that evolves in a homogeneous medium is proposed to revisit GRB 090510 and explain the multiwavelength light curve observations presented in this burst. These observations are consistent with the evolution of a jet before and after the jet break. The long-lasting LAT, X-ray, and optical fluxes are explained in the synchrotron emission from the adiabatic forward shock. Synchrotron self-Compton emission from the reverse shock is consistent with the bright LAT peak provided that the progenitor environment is entrained with strong magnetic fields. It could provide compelling evidence of magnetic field amplification in the neutron star merger.

  9. THE AFTERGLOW AND ULIRG HOST GALAXY OF THE DARK SHORT GRB 120804A

    Energy Technology Data Exchange (ETDEWEB)

    Berger, E.; Zauderer, B. A.; Margutti, R.; Laskar, T.; Fong, W.; Chornock, R.; Dupuy, T. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Levan, A.; Tunnicliffe, R. L. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Mangano, V. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Fox, D. B. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Menten, K. M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Hjorth, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Roth, K. [Gemini Observatory, 670 North Aohoku Place, Hilo, HI 96720 (United States)

    2013-03-10

    We present the optical discovery and subarcsecond optical and X-ray localization of the afterglow of the short GRB 120804A, as well as optical, near-IR, and radio detections of its host galaxy. X-ray observations with Swift/XRT, Chandra, and XMM-Newton extending to {delta}t Almost-Equal-To 19 days reveal a single power-law decline. The optical afterglow is faint, and comparison to the X-ray flux indicates that GRB 120804A is ''dark'', with a rest-frame extinction of A {sup host}{sub V} Almost-Equal-To 2.5 mag (at z = 1.3). The intrinsic neutral hydrogen column density inferred from the X-ray spectrum, N{sub H,{sub int}}(z = 1.3) Almost-Equal-To 2 Multiplication-Sign 10{sup 22} cm{sup -2}, is commensurate with the large extinction. The host galaxy exhibits red optical/near-IR colors. Equally important, JVLA observations at Almost-Equal-To 0.9-11 days reveal a constant flux density of F{sub {nu}}(5.8 GHz) = 35 {+-} 4 {mu}Jy and an optically thin spectrum, unprecedented for GRB afterglows, but suggestive instead of emission from the host galaxy. The optical/near-IR and radio fluxes are well fit with the scaled spectral energy distribution of the local ultraluminous infrared galaxy (ULIRG) Arp 220 at z Almost-Equal-To 1.3, with a resulting star formation rate of x Almost-Equal-To 300 M{sub Sun} yr{sup -1}. The inferred extinction and small projected offset (2.2 {+-} 1.2 kpc) are also consistent with the ULIRG scenario, as is the presence of a companion galaxy at the same redshift and with a separation of about 11 kpc. The limits on radio afterglow emission, in conjunction with the observed X-ray and optical emission, require a circumburst density of n {approx} 10{sup -3} cm{sup -3}, an isotropic-equivalent energy scale of E{sub {gamma},{sub iso}} Almost-Equal-To E{sub K,{sub iso}} Almost-Equal-To 7 Multiplication-Sign 10{sup 51} erg, and a jet opening angle of {theta}{sub j} {approx}> 11 Degree-Sign . The expected fraction of luminous infrared

  10. Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

    International Nuclear Information System (INIS)

    Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

    1998-01-01

    The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

  11. Recombination of KrD{sup +} and KrH{sup +} ions in afterglow plasma

    Energy Technology Data Exchange (ETDEWEB)

    Korolov, I; Kotrik, T; Plasil, R; Hejduk, M; Varju, J; Dohnal, P; Glosik, J, E-mail: juraj.glosik@mff.cuni.c [Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University in Prague (Czech Republic)

    2009-11-15

    Reported is flowing afterglow (FALP) study of recombination of KrH{sup +} and KrD{sup +} ions with electrons at 250 K in mixtures of He/Kr/H{sub 2} and He/Kr/D{sub 2}, respectively. The influence of fast recombining cluster ions formation on apparent effective recombination rate coefficients ({alpha}{sub eff}) was measured and used in data analysis. The obtained binary rate coefficients for recombination of KrH{sup +} and KrD{sup +} are {alpha}{sub KrH+} = 2x10{sup -8} cm{sup 3}s{sup -1} and {alpha}{sub KrD+} = 1x10{sup -8} cm{sup 3}s{sup -1}.

  12. Early GRB optical and infrared afterglow observations with the 2-m robotic Liverpool Telescope

    International Nuclear Information System (INIS)

    Gomboc, A.; Ljubljana Univ., Ljubljana; Mundell, C.G.; Guidorzi, C.

    2005-01-01

    We present the first optical observations of a Gamma Ray Burst IGRB) afterglow using the 2-m robotic Liverpool Telescope (LT), which is owned and operated by Liverpool John Moores University and situated on La Palma. We briefly discuss the capabilities of LT and its suitability for rapid follow-up observations of early optical and infrared GRB light curves. In particular, the combination of aperture, site, instrumentation and rapid response (robotic over-ride mode aided by telescope's rapid slew and fully-opening enclosure) makes the LT ideal for investigating the nature of short bursts, optically-dark bursts, and GRB blast-wave physics in general. We briefly describe the LT's key position in the RoboNet-1.0 network of robotic telescopes. We present the LT observations of GRB041006 and use its gamma-ray properties to predict the time of the break in optical light curve, a prediction consistent with the observations

  13. The Giant Flare From SGR 1806-20 And Its Radio Afterglow

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G.B.; /New Mexico U. /NRAO, Socorro; Granot, J.; /KIPAC, Menlo Park

    2006-09-26

    The multi-wavelength observations of the 2004 December 27 Giant Flare (GF) from SGR 1806-20 and its long-lived radio afterglow are briefly reviewed. The GF appears to have been produced by a dramatic reconfiguration of the magnetic field near the surface of the neutron star, possibly accompanied by fractures in the crust. The explosive release of over 10{sup 46} erg (isotropic equivalent) powered a one-sided mildly relativistic outflow. The outflow produced a new expanding radio nebula, that is still visible over a year after the GF. Also considered are the constraints on the total energy in the GF, the energy and mass in the outflow, and on the external density, as well as possible implications for short {gamma}-ray bursts and potential signatures in high energy neutrinos, photons, or cosmic rays. Some possible future observations of this and other GFs are briefly discussed.

  14. PANCHROMATIC OBSERVATIONS OF THE TEXTBOOK GRB 110205A: CONSTRAINING PHYSICAL MECHANISMS OF PROMPT EMISSION AND AFTERGLOW

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, W. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109 (United States); Shen, R. F. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, Ontario M5S 3H4 (Canada); Sakamoto, T. [Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Beardmore, A. P. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); De Pasquale, M. [Mullard Space Science Laboratory, University College London, Holmbury Road, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom); Wu, X. F.; Zhang, B. [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States); Gorosabel, J. [Instituto de Astrofisica de Andalucia (IAA-CSIC), 18008 Granada (Spain); Urata, Y. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Sugita, S. [EcoTopia Science Institute, Nagoya University, Furo-cho, chikusa, Nagoya 464-8603 (Japan); Pozanenko, A. [Space Research Institute (IKI), 84/32 Profsoyuznaya St., Moscow 117997 (Russian Federation); Nissinen, M. [Taurus Hill Observatory, Haerkaemaeentie 88, 79480 Kangaslampi (Finland); Sahu, D. K. [CREST, Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Im, M. [Center for the Exploration of the Origin of the Universe, Department of Physics and Astronomy, FPRD, Seoul National University, Shillim-dong, San 56-1, Kwanak-gu, Seoul (Korea, Republic of); Ukwatta, T. N. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Andreev, M. [Terskol Branch of Institute of Astronomy of RAS, Kabardino-Balkaria Republic 361605 (Russian Federation); Klunko, E., E-mail: zwk@umich.edu, E-mail: rfshen@astro.utoronto.ca, E-mail: zhang@physics.unlv.edu [Institute of Solar-Terrestrial Physics, Lermontov St., 126a, Irkutsk 664033 (Russian Federation); and others

    2012-06-01

    We present a comprehensive analysis of a bright, long-duration (T{sub 90} {approx} 257 s) GRB 110205A at redshift z = 2.22. The optical prompt emission was detected by Swift/UVOT, ROTSE-IIIb, and BOOTES telescopes when the gamma-ray burst (GRB) was still radiating in the {gamma}-ray band, with optical light curve showing correlation with {gamma}-ray data. Nearly 200 s of observations were obtained simultaneously from optical, X-ray, to {gamma}-ray (1 eV to 5 MeV), which makes it one of the exceptional cases to study the broadband spectral energy distribution during the prompt emission phase. In particular, we clearly identify, for the first time, an interesting two-break energy spectrum, roughly consistent with the standard synchrotron emission model in the fast cooling regime. Shortly after prompt emission ({approx}1100 s), a bright (R = 14.0) optical emission hump with very steep rise ({alpha} {approx} 5.5) was observed, which we interpret as the reverse shock (RS) emission. It is the first time that the rising phase of an RS component has been closely observed. The full optical and X-ray afterglow light curves can be interpreted within the standard reverse shock (RS) + forward shock (FS) model. In general, the high-quality prompt and afterglow data allow us to apply the standard fireball model to extract valuable information, including the radiation mechanism (synchrotron), radius of prompt emission (R{sub GRB} {approx} 3 Multiplication-Sign 10{sup 13} cm), initial Lorentz factor of the outflow ({Gamma}{sub 0} {approx} 250), the composition of the ejecta (mildly magnetized), the collimation angle, and the total energy budget.

  15. DUST PROPERTIES IN THE AFTERGLOW OF GRB 071025 AT z {approx} 5

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Minsung; Im, Myungshin [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Lee, Induk; Urata, Yuji [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun; Hirashita, Hiroyuki [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Fan Xiaohui; Jiang Linhua, E-mail: msjang.astro@gmail.com, E-mail: mim@astro.snu.ac.kr [Steward Observatory, University of Arizona, Tucson, AZ (United States)

    2011-11-15

    At high redshift, the universe is so young that core-collapse supernovae (SNe) are suspected to be the dominant source of dust production. However, some observations indicate that the dust production by SNe is an inefficient process, casting doubts on the existence of abundant SNe-dust in the early universe. Recently, Perley et al. reported that the afterglow of GRB 071025-an unusually red gamma-ray burst (GRB) at z {approx} 5-shows evidence for SNe-produced dust. Since this is perhaps the only high-redshift GRB exhibiting compelling evidence for SNe-dust but the result could easily be affected by small systematics in photometry, we re-examined the extinction properties of GRB 071025 using our own optical/near-infrared data at a different epoch. In addition, we tested SNe-dust models with different progenitor masses and dust destruction efficiencies to constrain the dust formation mechanisms. By searching for the best-fit model of the afterglow spectral energy distribution, we confirm the previous claim that the dust in GRB 071025 is most likely to originate from SNe. We also find that the SNe-dust model of 13 or 25 M{sub Sun} without dust destruction fits the extinction property of GRB 071025 best, while pair-instability SNe models with a 170 M{sub Sun} progenitor poorly fit the data. Our results indicate that, at least in some systems at high redshift, SNe with intermediate initial masses within 10-30 M{sub Sun} were the main contributors for the dust enrichment, and the dust destruction effect due to reverse shock was negligible.

  16. Gamma-Ray Burst Dynamics and Afterglow Radiation from Adaptive Mesh Refinement, Special Relativistic Hydrodynamic Simulations

    Science.gov (United States)

    De Colle, Fabio; Granot, Jonathan; López-Cámara, Diego; Ramirez-Ruiz, Enrico

    2012-02-01

    We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with ρvpropr -k , bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the relativistic flow.

  17. GAMMA-RAY BURST DYNAMICS AND AFTERGLOW RADIATION FROM ADAPTIVE MESH REFINEMENT, SPECIAL RELATIVISTIC HYDRODYNAMIC SIMULATIONS

    International Nuclear Information System (INIS)

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; López-Cámara, Diego

    2012-01-01

    We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with ρ∝r –k , bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the relativistic flow.

  18. GAMMA-RAY BURST DYNAMICS AND AFTERGLOW RADIATION FROM ADAPTIVE MESH REFINEMENT, SPECIAL RELATIVISTIC HYDRODYNAMIC SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    De Colle, Fabio; Ramirez-Ruiz, Enrico [Astronomy and Astrophysics Department, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)

    2012-02-20

    We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with {rho}{proportional_to}r{sup -k}, bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the

  19. GAMMA-RAY BURST REVERSE SHOCK EMISSION IN EARLY RADIO AFTERGLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Resmi, Lekshmi [Indian Institute of Space Science and Technology, Trivandrum (India); Zhang, Bing, E-mail: l.resmi@iist.ac.in [Department of Physics and Astronomy, University of Nevada, Las Vegas (United States)

    2016-07-01

    Reverse shock (RS) emission from gamma-ray bursts is an important tool in investigating the nature of the ejecta from the central engine. If the magnetization of the ejecta is not high enough to suppress the RS, a strong RS emission component, usually peaking in the optical/IR band early on, would provide an important contribution to early afterglow light curve. In the radio band, synchrotron self-absorption may suppress early RS emission and also delay the RS peak time. In this paper, we calculate the self-absorbed RS emission in the radio band under different dynamical conditions. In particular, we stress that the RS radio emission is subject to self-absorption in both RSs and forward shocks (FSs). We calculate the ratio between the RS to FS flux at the RS peak time for different frequencies, which is a measure of the detectability of the RS emission component. We then constrain the range of physical parameters for a detectable RS, in particular the role of magnetization. We notice that unlike optical RS emission which is enhanced by moderate magnetization, moderately magnetized ejecta do not necessarily produce a brighter radio RS due to the self-absorption effect. For typical parameters, the RS emission component would not be detectable below 1 GHz unless the medium density is very low (e.g., n < 10{sup −3} cm{sup −3} for the interstellar medium and A {sub *} < 5 × 10{sup −4} for wind). These predictions can be tested using the afterglow observations from current and upcoming radio facilities such as the Karl G. Jansky Very Large Array, the Low-Frequency Array, the Five Hundred Meter Aperture Spherical Telescope, and the Square Kilometer Array.

  20. The Arcminute Microkelvin Imager catalogue of gamma-ray burst afterglows at 15.7 GHz

    Science.gov (United States)

    Anderson, G. E.; Staley, T. D.; van der Horst, A. J.; Fender, R. P.; Rowlinson, A.; Mooley, K. P.; Broderick, J. W.; Wijers, R. A. M. J.; Rumsey, C.; Titterington, D. J.

    2018-01-01

    We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7 GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target within 2 min, scheduling later start times if the source is below the horizon. Further AMI observations are manually scheduled for several days following the trigger. The AMI GRB programme probes the early-time (<1 d) radio properties of GRBs, and has obtained some of the earliest radio detections (GRB 130427A at 0.36 and GRB 130907A at 0.51 d post-burst). As all Swift GRBs visible to AMI are observed, this catalogue provides the first representative sample of GRB radio properties, unbiased by multiwavelength selection criteria. We report the detection of six GRB radio afterglows that were not previously detected by other radio telescopes, increasing the rate of radio detections by 50 per cent over an 18-month period. The AMI catalogue implies a Swift GRB radio detection rate of ≳ 15 per cent, down to ∼0.2 mJy beam-1. However, scaling this by the fraction of GRBs AMI would have detected in the Chandra & Frail sample (all radio-observed GRBs between 1997 and 2011), it is possible ∼ 44-56 per cent of Swift GRBs are radio bright, down to ∼0.1-0.15 mJy beam-1. This increase from the Chandra & Frail rate (∼30 per cent) is likely due to the AMI rapid-response mode, which allows observations to begin while the reverse-shock is contributing to the radio afterglow.

  1. Afterglow Imaging and Polarization of Misaligned Structured GRB Jets and Cocoons: Breaking the Degeneracy in GRB 170817A

    Science.gov (United States)

    Gill, Ramandeep; Granot, Jonathan

    2018-05-01

    The X-ray to radio afterglow emission of GRB 170817A / GW 170817 so far scales as Fν∝ν-0.6t0.8 with observed frequency and time, consistent with a single power-law segment of the synchrotron spectrum from the external shock going into the ambient medium. This requires the effective isotropic equivalent afterglow shock energy in the visible region to increase as ˜t1.7. The two main channels for such an energy increase are (i) radial: more energy carried by slower material (in the visible region) gradually catches up with the afterglow shock and energizes it, and (ii) angular: more energy in relativistic outflow moving at different angles to our line of sight, whose radiation is initially beamed away from us but its beaming cone gradually reaches our line of sight as it decelerates. One cannot distinguish between these explanations (or combinations of them) using only the X-ray to radio Fν(t). Here we demonstrate that the most promising way to break this degeneracy is through afterglow imaging and polarization, by calculating the predicted evolution of the afterglow image (its size, shape and flux centroid) and linear polarization Π(t) for different angular and/or radial outflow structures that fit Fν(t). We consider two angular profiles - a Gaussian and a narrow core with power-law wings in energy per solid angle, as well as a (cocoon motivated) (quasi-) spherical flow with radial velocity profile. For a jet viewed off-axis (and a magnetic field produced in the afterglow shock) Π(t) peaks when the jet's core becomes visible, at ≈2tp where the lightcurve peaks at tp, and the image can be elongated with aspect ratios ≳ 2. A quasi-spherical flow has an almost circular image and a much lower Π(t) (peaking at ≈tp) and flux centroid displacement θfc (a spherical flow has Π(t) = θfc = 0 and a perfectly circular image).

  2. Lifetime and quenching of CO /a super 3 pi/ produced by recombination of CO2 ions in a helium afterglow.

    Science.gov (United States)

    Wauchop, T. S.; Broida, H. P.

    1972-01-01

    Demonstration that rapid dissociative recombination of CO2(+) in a flowing, helium afterglow is an efficient source of CO in the a super 3 pi metastable state. Ions produced by mixing CO2 with He(2 super 3 S) recombine to produce a CO metastable afterglow with a number density as great as 10 to the 9th per sq cm. Monitoring of the (a super 3 pi-X super 1 sigma) Cameron transition in CO was used to study the lifetime and quenching of CO (a super 3 pi) by CO2, N2, NO, and He. Recombination of CO2(+) also produces CO in the d super 3 delta and a' super 3 sigma states.

  3. Two Early Gamma-ray Bursts Optical Afterglow Detections with TAOS Telescopes--GRB 071010B and GRB 071112C

    International Nuclear Information System (INIS)

    Huang, K. Y.; Wang, S. Y.; Urata, Y.

    2009-01-01

    We present on two early detections of GRB afterglows with the Taiwanese-American Occltation Sruvey (TAOS) telescopes. The robotic TAOS system has been devised so that the routine Kuiper Belt Object (KBO) survey is interrupted when a GRB alert is triggered. Our first detection, GRB 071010B was detected by TAOS 62 s after the burst and showed a weak early brightening during the observations. No significant correction with the prompt gamma-ray emission indicated that our optical emission detected is afterglow emission. The second detection of TAOS, GRB 071112C was detected 96 s after the burst, also showed a possible initial raising then followed a steep decay in the R-band light curve.

  4. Observation of visible emission from the molecular helium ion in the afterglow of a dense helium Z-pinch plasma

    International Nuclear Information System (INIS)

    Tucker, J.E.; Brake, M.L.; Gilgenbach, R.M.

    1986-01-01

    The authors present the results of axial and radial time resolved visible emission spectroscopy from the afterglow of a dense helium Z-pinch. These results show that the visible emissions in the pinch afterglow are dominated by line emissions from molecular helium and He II. Axial spectroscopy measurements show the occurrence of several absorption bands which cannot be identified as molecular or atomic helium nor impurities from the discharge chamber materials. The authors believe that these absorption bands are attributable to the molecular helium ion which is present in the discharge. The molecular ion has been observed by others in low pressure and temperature helium discharges directly by means of mass spectrometry and indirectly by the presence of helium atoms in the 2/sup 3/S state, (the He 2/sup 3/S state is believed to result from molecular helium ion recombination). However, the molecular helium ion has not previously been observed spectroscopically

  5. Simulation of the Plasma Afterglow in the Discharge Gap of a Subnanosecond Switch Based on an Open Discharge in Helium

    Science.gov (United States)

    Alexandrov, A. L.; Schweigert, I. V.

    2018-05-01

    The phenomenon of subnanosecond electrical breakdown in a strong electric field observed in an open discharge in helium at pressures of 6-20 Torr can be used to create ultrafast plasma switches triggering into a conducting state for a time shorter than 1 ns. To evaluate the possible repetition rate of such a subnanosecond switch, it is interesting to study the decay dynamics of the plasma remaining in the discharge gap after ultrafast breakdown. In this paper, a kinetic model based on the particle-in-cell Monte Carlo collision method is used to study the dynamics of the plasma afterglow in the discharge gap of a subnanosecond switch operating with helium at a pressure of 6 Torr. The simulation results show that the radiative, collisional-radiative, and three-body collision recombination mechanisms significantly contribute to the afterglow decay only while the plasma density remains higher than 1012 cm-3; the main mechanism of the further plasma decay is diffusion of plasma particles onto the wall. Therefore, the effect of recombination in the plasma bulk is observed only during the first 10-20 μs of the afterglow. Over nearly the same time, plasma electrons become thermalized. The afterglow time can be substantially reduced by applying a positive voltage U c to the cathode. Since diffusive losses are limited by the ion mobility, the additional ion drift toward the wall significantly accelerates plasma decay. As U c increases from 0 to +500 V, the characteristic time of plasma decay is reduced from 35 to 10 μs.

  6. Luminescent Afterglow Behavior in the M2Si5N8: Eu Family (M = Ca, Sr, Ba

    Directory of Open Access Journals (Sweden)

    Koen Van den Eeckhout

    2011-05-01

    Full Text Available Persistent luminescent materials are able to emit light for hours after being excited. The majority of persistent phosphors emit in the blue or green region of the visible spectrum. Orange- or red-emitting phosphors, strongly desired for emergency signage and medical imaging, are scarce. We prepared the nitrido-silicates Ca2Si5N8:Eu (orange, Sr2Si5N8:Eu (reddish, Ba2Si5N8:Eu (yellowish orange, and their rare-earth codoped variants (R = Nd, Dy, Sm, Tm through a solid state reaction, and investigated their luminescence and afterglow properties. In this paper, we describe how the persistent luminescence is affected by the type of codopant and the choice and ratio of the starting products. All the materials exhibit some form of persistent luminescence, but for Sr2Si5N8:Eu,R this is very weak. In Ba2Si5N8:Eu the afterglow remains visible for about 400 s, and Ca2Si5N8:Eu,Tm shows the brightest and longest afterglow, lasting about 2,500 s. For optimal persistent luminescence, the dopant and codopant should be added in their fluoride form, in concentrations below 1 mol%. A Ca3N2 deficiency of about 5% triples the afterglow intensity. Our results show that Ba2Si5N8:Eu(,R and Ca2Si5N8:Eu(,R are promising persistent phosphors for applications requiring orange or red light.

  7. THE OPTICAL AFTERGLOW AND z = 0.92 EARLY-TYPE HOST GALAXY OF THE SHORT GRB 100117A

    International Nuclear Information System (INIS)

    Fong, W.; Berger, E.; Chornock, R.; Tanvir, N. R.; Levan, A. J.; Fruchter, A. S.; Graham, J. F.; Cucchiara, A.; Fox, D. B.

    2011-01-01

    We present the discovery of the optical afterglow and early-type host galaxy of the short-duration GRB 100117A. The faint afterglow is detected 8.3 hr after the burst with r AB = 25.46 ± 0.20 mag. Follow-up optical and near-infrared observations uncover a coincident compact red galaxy, identified as an early-type galaxy at a spectroscopic redshift of z ∼ 0.915 with a mass of ∼3 x 10 10 M sun , an age of ∼1 Gyr, and a luminosity of L B ≅ 0.5 L * . From a possible weak detection of [O II]λ3727 emission at z = 0.915 we infer an upper bound on the star formation rate of ∼0.1 M sun yr -1 , leading to a specific star formation rate of ∼ -1 . Thus, GRB 100117A is only the second short burst to date with a secure early-type host (the other being GRB 050724 at z = 0.257) and it has one of the highest short gamma-ray burst (GRB) redshifts. The offset between the host center and the burst position, 470 ± 310 pc, is the smallest to date. Combined with the old stellar population age, this indicates that the burst likely originated from a progenitor with no significant kick velocity. However, from the brightness of the optical afterglow we infer a relatively low density of n ∼ 3 x 10 -4 ε -3 e,-1 ε -1.75 B,-1 cm -3 . The combination of an optically faint afterglow and host suggests that previous such events may have been missed, thereby potentially biasing the known short GRB host population against z ∼> 1 early-type hosts.

  8. Implications from the Upper Limit of Radio Afterglow Emission of FRB 131104/Swift J0644.5-5111

    Science.gov (United States)

    Gao, He; Zhang, Bing

    2017-02-01

    A γ-ray transient, Swift J0644.5-5111, has been claimed to be associated with FRB 131104. However, a long-term radio imaging follow-up observation only placed an upper limit on the radio afterglow flux of Swift J0644.5-5111. Applying the external shock model, we perform a detailed constraint on the afterglow parameters for the FRB 131104/Swift J0644.5-5111 system. We find that for the commonly used microphysics shock parameters (e.g., {ɛ }e=0.1, {ɛ }B=0.01, and p = 2.3), if the fast radio burst (FRB) is indeed cosmological as inferred from its measured dispersion measure (DM), the ambient medium number density should be ≤slant {10}-3 {{cm}}-3, which is the typical value for a compact binary merger environment but disfavors a massive star origin. Assuming a typical ISM density, one would require that the redshift of the FRB be much smaller than the value inferred from DM (z\\ll 0.1), implying a non-cosmological origin of DM. The constraints are much looser if one adopts smaller {ɛ }B and {ɛ }e values, as observed in some gamma-ray burst afterglows. The FRB 131104/Swift J0644.5-5111 association remains plausible. We critically discuss possible progenitor models for the system.

  9. The afterglow of GRB 050709 and the nature of the short-hard gamma-ray bursts.

    Science.gov (United States)

    Fox, D B; Frail, D A; Price, P A; Kulkarni, S R; Berger, E; Piran, T; Soderberg, A M; Cenko, S B; Cameron, P B; Gal-Yam, A; Kasliwal, M M; Moon, D-S; Harrison, F A; Nakar, E; Schmidt, B P; Penprase, B; Chevalier, R A; Kumar, P; Roth, K; Watson, D; Lee, B L; Shectman, S; Phillips, M M; Roth, M; McCarthy, P J; Rauch, M; Cowie, L; Peterson, B A; Rich, J; Kawai, N; Aoki, K; Kosugi, G; Totani, T; Park, H-S; MacFadyen, A; Hurley, K C

    2005-10-06

    The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.

  10. Afterglow properties of CaF{sub 2}:Tm nanoparticles and its potential application in photodynamic therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zahedifar, M., E-mail: zhdfr@kashanu.ac.ir [Physics Department, University of Kashan, Kashan, I.R. Iran (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechniology, University of Kashan, Kashan, I.R. Iran (Iran, Islamic Republic of); Sadeghi, E. [Physics Department, University of Kashan, Kashan, I.R. Iran (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechniology, University of Kashan, Kashan, I.R. Iran (Iran, Islamic Republic of); Shanei, M.M. [Institute of Nanoscience and Nanotechniology, University of Kashan, Kashan, I.R. Iran (Iran, Islamic Republic of); Sazgarnia, A. [Research Center and Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Vakil Abad Blvd., Mashhad (Iran, Islamic Republic of); Mehrabi, M. [Institute of Nanoscience and Nanotechniology, University of Kashan, Kashan, I.R. Iran (Iran, Islamic Republic of)

    2016-03-15

    CaF{sub 2}:Tm nanoparticles (NPs) were synthesized by the hydrothermal method. Intense afterglow emission with long life time was found for the produced NPs, so its applicability in photodynamic therapy was investigated. Since the wavelength of the afterglow emission of the NPs fairly matches with the absorption band of the PpIX sensitizer, especially in the red region, the Cystein mediator was used to bond NPs with the PpIX sensitizer. The CaF{sub 2}:Tm NPs conjugated with PpIX was exposed to X-ray and by using the Antracene as detector, the production of the singlet oxygen was verified. Therefore, the produced NPs are recommended as a source of energy that improves photodynamic therapy beyond its current limitations. - Highlights: • Intense afterglow emission found for the synthesized CaF{sub 2}:Tm nanoparticles. • CaF{sub 2}:Tm emission band fairly matched with PpIX sensitizer's absorption band. • CaF{sub 2}:Tm conjugated with the sensitized is a good candidate for photodynamic therapy. • The application of nanoparticles in producing singlet oxygen was verified.

  11. The influence of the N(2D) and N(2P) states in the ionization of the pink afterglow of the nitrogen flowing DC discharge

    Science.gov (United States)

    Levaton, J.; Klein, A. N.; Binder, C.

    2018-01-01

    In the present work, we extensively discuss the role of N(2D) and N(2P) atoms in the ionization processes of pink afterglow based on optical emission spectroscopy analysis and kinetic numerical modelling. We studied the pink afterglow generated by a nitrogen DC discharge operating at 0.6 Slm-1 flow rate, 45 mA discharge current and pressures ranging from 250 to 1050 Pa. The 391.4 nm nitrogen band was monitored along the afterglow furnishing the relative density of the N2+(B2Σ+u, v = 0) state. A numerical model developed to calculate the nitrogen species densities in the afterglow fits the excited ion density profiles well for the experimental conditions. From the modelling results, we determine the densities of the N+, N2+, N3+, and N4+ ions; the calculations show that the N3+ ion density predominates in the afterglow at the typical residence times of the pink afterglow. This behaviour has been observed experimentally and reported in the literature. Furthermore, we calculate the fractional contribution in the ionization for several physical-chemical mechanisms in the post-discharge. Even with the N3+ ion density being dominant in the afterglow, we find through the calculations that the ionization is dominated by the reactions N(2D) + N(2P) → N2+(X2Σ+g) + e and N2(a'1Σ-u) + N2(X 1Σg+, v > 24) → N4+ + e. The ion conversion mechanisms, or ion transfer reactions, which are responsible for the fact that the N3+ density dominates in the post-discharge, are investigated.

  12. GEMINI SPECTROSCOPY OF THE SHORT-HARD GAMMA-RAY BURST GRB 130603B AFTERGLOW AND HOST GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Cucchiara, A.; Prochaska, J. X.; Werk, J. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Perley, D.; Cao, Y. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd, Pasadena, CA 91125 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD (United States); Cardwell, A.; Turner, J. [Gemini South Observatory, AURA, Casilla 603, La Serena (Chile); Bloom, J. S. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Cobb, B. E., E-mail: acucchia@ucolick.org [The George Washington University, Washington, DC (United States)

    2013-11-10

    We present early optical photometry and spectroscopy of the afterglow and host galaxy of the bright short-duration gamma-ray burst GRB 130603B discovered by the Swift satellite. Using our Target of Opportunity program on the Gemini South telescope, our prompt optical spectra reveal a strong trace from the afterglow superimposed on continuum and emission lines from the z = 0.3568 ± 0.0005 host galaxy. The combination of a relatively bright optical afterglow (r' = 21.52 at Δt = 8.4 hr), together with an observed offset of 0.''9 from the host nucleus (4.8 kpc projected distance at z = 0.3568), allow us to extract a relatively clean spectrum dominated by afterglow light. Furthermore, the spatially resolved spectrum allows us to constrain the properties of the explosion site directly, and compare these with the host galaxy nucleus, as well as other short-duration GRB host galaxies. We find that while the host is a relatively luminous (L∼0.8 L{sup *}{sub B}), star-forming (SFR = 1.84 M{sub ☉} yr{sup –1}) galaxy with almost solar metallicity, the spectrum of the afterglow exhibits weak Ca II absorption features but negligible emission features. The explosion site therefore lacks evidence of recent star formation, consistent with the relatively long delay time distribution expected in a compact binary merger scenario. The star formation rate (SFR; both in an absolute sense and normalized to the luminosity) and metallicity of the host are both consistent with the known sample of short-duration GRB hosts and with recent results which suggest GRB 130603B emission to be the product of the decay of radioactive species produced during the merging process of a neutron-star-neutron-star binary ({sup k}ilonova{sup )}. Ultimately, the discovery of more events similar to GRB 130603B and their rapid follow-up from 8 m class telescopes will open new opportunities for our understanding of the final stages of compact-objects binary systems and provide crucial

  13. 'Jet breaks' and 'missing breaks' in the X-Ray afterglow of Gamma Ray Bursts

    CERN Document Server

    Dado, Shlomo; De Rújula, Alvaro

    2008-01-01

    The X-ray afterglows (AGs) of Gamma-Ray Bursts (GRBs) and X-Ray Flashes (XRFs) have, after the fast decline phase of their prompt emission, a temporal behaviour varying between two extremes. A large fraction of these AGs has a 'canonical' light curve which, after an initial shallow-decay 'plateau' phase, 'breaks smoothly' into a fast power-law decline. Very energetic GRBs, contrariwise, appear not to have a 'break', their AG declines like a power-law from the start of the observations. Breaks and 'missing breaks' are intimately related to the geometry and deceleration of the jets responsible for GRBs. In the frame of the 'cannonball' (CB) model of GRBs and XRFs, we analyze the cited extreme behaviours (canonical and pure power-law) and intermediate cases spanning the observed range of X-ray AG shapes. We show that the entire panoply of X-ray light-curve shapes --measured with Swift and other satellites-- are as anticipated, on very limpid grounds, by the CB model. We test the expected correlations between the...

  14. A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope

    Directory of Open Access Journals (Sweden)

    Yuji Urata

    2015-01-01

    Full Text Available Planned rapid submillimeter (submm gamma-ray-bursts (GRBs follow-up observations conducted using the Greenland Telescope (GLT are presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high altitude and dry weather porvide excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1 systematic detection of bright submm emissions originating from reverse shock (RS in the early afterglow phase, (2 characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3 detections of GRBs at a high redshift as a result of the explosion of first generation stars through systematic rapid follow-ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies.

  15. A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope

    Science.gov (United States)

    Urata, Yuji; Huang, Kuiyun; Asada, Keiichi; Hirashita, Hiroyuki; Inoue, Makoto; Ho, Paul T. P.

    A planned rapid submillimeter (submm) Gamma Ray Burst (GRBs) follow-up observations conducted using the Greenland Telescope (GLT) is presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high-altitude and dry weather porvides excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1) systematic detection of bright submm emissions originating from reverse shock (RS) in the early afterglow phase, (2) characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3) detections of GRBs as a result of the explosion of first-generation stars result of GRBs at a high redshift through systematic rapid follow ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies.

  16. Prompt and Afterglow Emission Properties of Gamma-Ray Bursts with Spectroscopically Identified Supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Yuki; Ramirez-Ruiz, E.; Granot, J.; Kouveliotou, C.; Woosley, S.E.; Patel, S.K.; Rol, E.; Zand, J.J.M.in' t; a; Wijers, R.A.M.J.; Strom, R.; /USRA, Huntsville

    2006-07-12

    We present a detailed spectral analysis of the prompt and afterglow emission of four nearby long-soft gamma-ray bursts (GRBs 980425, 030329, 031203, and 060218) that were spectroscopically found to be associated with type Ic supernovae, and compare them to the general GRB population. For each event, we investigate the spectral and luminosity evolution, and estimate the total energy budget based upon broadband observations. The observational inventory for these events has become rich enough to allow estimates of their energy content in relativistic and sub-relativistic form. The result is a global portrait of the effects of the physical processes responsible for producing long-soft GRBs. In particular, we find that the values of the energy released in mildly relativistic outflows appears to have a significantly smaller scatter than those found in highly relativistic ejecta. This is consistent with a picture in which the energy released inside the progenitor star is roughly standard, while the fraction of that energy that ends up in highly relativistic ejecta outside the star can vary dramatically between different events.

  17. New flowing afterglow technique for determining products of dissociative recombination: CH5+ and N2H+

    International Nuclear Information System (INIS)

    Adams, Nigel G; Molek, Chris D; McLain, Jason L

    2009-01-01

    There are discrepancies in the literature for the product distributions of electron-ion (e-i) recombination when determined using different techniques. Because of this, a new technique has been developed. This is based on the flowing afterglow, with the product neutrals detected by electron impact ionization followed by mass spectrometric detection. However, in addition to the products of recombination, there are neutrals present from ion-molecule reactions and from the gases introduced into the flow tube to create the ion of interest, which often have much greater concentrations than the products. To distinguish these products, an electron attaching gas is pulsed into the flow to transiently attach the electrons, thus quenching e-i recombination. Then the difference between the attaching gas in and out yields the product distribution. Recombination products have been detected even when their signal is as much as ∼ 10 4 less than background. Here the details of the technique are described and the possible sources of error discussed. The viability of the technique is illustrated for the recombinations of CH 5 + and N 2 H + . The latter establishes the major product as N 2 + H (95 to 100%) correcting an error in the literature. In the former case, the major channel detected is CH 4 + H (95%) which is in disagreement with a storage ring (SR) result which gave CH 3 as the major channel (68%). Possible reasons for this are discussed.

  18. Measurement of gas temperature and OH density in the afterglow of pulsed positive corona discharge

    International Nuclear Information System (INIS)

    Ono, Ryo; Oda, Tetsuji

    2008-01-01

    The gas temperature and OH density in the afterglow of pulsed positive corona discharge are measured using the laser-induced predissociation fluorescence (LIPF) of OH radicals. Discharge occurs in a 13 mm point-to-plane gap in an atmospheric-pressure H 2 O(2.8%)/O 2 (2.0%)/N 2 mixture. The temperature measurement shows that (i) the temperature increases after discharge and (ii) the temperature near the anode tip (within 1 mm from the anode tip) is much higher than that of the rest of the discharge volume. Near the anode tip, the temperature increases from 500 K (t = 0 μs) to 1100 K (t = 20 μs), where t is the postdischarge time, while it increases from 400 K (t = 0 μs) to 700 K (t = 100 μs) in the rest of the discharge volume away from the anode tip. This temperature difference between the two volumes (near and far from the anode tip) causes a difference in the decay rate of OH density: OH density near the anode tip decays approximately 10 times slower than that far from the tip. The spatial distribution of OH density shows good agreement with that of the secondary streamer luminous intensity. This shows that OH radicals are mainly produced in the secondary streamer, not in the primary one

  19. The effect of a direct current field on the microparticle charge in the plasma afterglow

    Energy Technology Data Exchange (ETDEWEB)

    Wörner, L. [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany); Groupe de Recherches sur l' Energétique des Milieux Ionisés, UMR7344, CNRS, Univ. Orléans, F-45067 Orléans (France); Ivlev, A. V.; Huber, P.; Hagl, T.; Thomas, H. M.; Morfill, G. E. [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany); Couëdel, L. [Centre National de la Recherche Scientifique, Aix-Marseille-Université, Laboiratoire de Physique des Intéractions Ioniques et Moléculaires, UMR 7345, 13397 Marseille cedex 20 (France); Schwabe, M. [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany); Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 (United States); Mikikian, M.; Boufendi, L. [Groupe de Recherches sur l' Energétique des Milieux Ionisés, UMR7344, CNRS, Univ. Orléans, F-45067 Orléans (France); Skvortsov, A. [Yuri Gagarin Cosmonauts Training Center, RU-141160 Star City (Russian Federation); Lipaev, A. M.; Molotkov, V. I.; Petrov, O. F.; Fortov, V. E. [Joint Institute for High Temperatures, RU-125412 Moscow (Russian Federation)

    2013-12-15

    Residual charges of individual microparticles forming dense clouds were measured in a RF discharge afterglow. Experiments were performed under microgravity conditions on board the International Space Station, which ensured particle levitation inside the gas volume after the plasma switch-off. The distribution of residual charges as well as the spatial distribution of charged particles across the cloud were analyzed by applying a low-frequency voltage to the electrodes and measuring amplitudes of the resulting particle oscillations. Upon “free decharging” conditions, the charge distribution had a sharp peak at zero and was rather symmetric (with charges concentrated between −10e and +10e), yet positively and negatively charged particles were homogeneously distributed over the cloud. However, when decharging evolved in the presence of an external DC field (applied shortly before the plasma switch-off) practically all residual charges were positive. In this case, the overall charge distribution had a sharp peak at about +15e and was highly asymmetric, while the spatial distribution exhibited a significant charge gradient along the direction of the applied DC field.

  20. REM observations of GRB060418 and GRB060607A: the onset of the afterglow and the initial fireball Lorentz factor determination

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, E.; Covino, S.; D' Avanzo, P.; Chincarini, G.; Zerbi, F.M.; Conconi, P.; Malaspina, G.; Campana, S.; Rizzuto, D.; Tagliaferri, G. [Osserv Astron Brera, INAF, I-23807 Merate, LC, (Italy); Vergani, S.D.; Meurs, E.J.A.; Ward, P.A. [DIAS, Dunsink Observ, Dublin 15, (Ireland); Vergani, S.D.; Norci, L. [Dublin City Univ, Sch Phys Sci, NCPST, Dublin 9, (Ireland); Malesani, D. [SISSA, ISAS, I-34014 Trieste, (Italy); Malesani, D. [Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, (Denmark); D' Avanzo, P. [Univ Insubria, Dipartimento Matemat and Fis, I-22100 Como, (Italy); Chincarini, G.; Rizzuto, D. [Univ Milan, I-20126 Milan, (Italy); Antonelli, L.A.; Testa, V.; Vitali, F.; D' Alessio, F.; Guetta, D.; Piranomonte, S.; Stella, L. [Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, (Italy); Tosti, G. [Univ Perugia, Dipartimento Fis, Osservatorio Astron, I-06123 Perugia, (Italy); Nicastro, L.; Palazzi, E.; Masetti, N. [IASF Bologna, INAF, I-40129 Bologna, (Italy); Goldoni, P. [APC, Lab Astroparticule and Cosmol, UMR 7164, F-75231 Paris 05, (France); Goldoni, P. [CEA Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, (France)] (and others)

    2007-07-01

    Context. Gamma-ray burst (GRB) emission is believed to originate in highly relativistic fireballs. Aims. Currently, only lower limits were securely set to the initial fireball Lorentz factor {gamma}{sub 0}. We aim to provide a direct measure of {gamma}{sub 0}. Methods. The early-time afterglow light curve carries information about {gamma}{sub 0}, which determines the time of the afterglow peak. We have obtained early observations of the near-infrared afterglows of GRB060418 and GRB060607A with the REM robotic telescope. Results. For both events, the afterglow peak could be clearly singled out, allowing a firm determination of the fireball Lorentz of {gamma}{sub 0} similar to 400, fully confirming the highly relativistic nature of GRB fireballs. The deceleration radius was inferred to be R-dec approximate to 10{sup 17} cm. This is much larger than the internal shocks radius (believed to power the prompt emission), thus providing further evidence for a different origin of the prompt and afterglow stages of the GRB. (authors)

  1. Characterization of the flowing afterglows of an N{sub 2}-O{sub 2} reduced-pressure discharge: setting the operating conditions to achieve a dominant late afterglow and correlating the NO{sub {beta}} UV intensity variation with the N and O atom densities

    Energy Technology Data Exchange (ETDEWEB)

    Boudam, M K [Groupe de Physique des Plasmas, Universite de Montreal, CP 6128, Succursale Centre-Ville, Montreal H3C 3J7, Quebec (Canada); Saoudi, B [Groupe de Physique des Plasmas, Universite de Montreal, CP 6128, Succursale Centre-Ville, Montreal H3C 3J7, Quebec (Canada); Moisan, M [Groupe de Physique des Plasmas, Universite de Montreal, CP 6128, Succursale Centre-Ville, Montreal H3C 3J7, Quebec (Canada); Ricard, A [Centre de Physique Atomique de Toulouse (CPAT), 118, route de Narbonne, Universite Paul Sabatier, 31062-Toulouse (France)

    2007-03-21

    The flowing afterglow of an N{sub 2}-O{sub 2} discharge in the 0.6-10 Torr range is examined in the perspective of achieving sterilization of medical devices (MDs) under conditions ensuring maximum UV intensity with minimum damage to polymer-based MDs. The early afterglow is shown to be responsible for creating strong erosion damage, requiring that the sterilizer be operated in a dominant late-afterglow mode. These two types of afterglow can be characterized by optical emission spectroscopy: the early afterglow is distinguished by an intense emission from the N{sub 2}{sup +} 1st negative system (band head at 391.4 nm) while the late afterglow yields an overpopulation of the v' = 11 ro-vibrational level of the N{sub 2}(B) state, indicating a reduced contribution from the early afterglow N{sub 2} metastable species. We have studied the influence of operating conditions (pressure, O{sub 2} content in the N{sub 2}-O{sub 2} mixture, distance of the discharge from the entrance to the afterglow (sterilizer) chamber) in order to achieve a dominant late afterglow that also ensures maximum and almost uniform UV intensity in the sterilization chamber. As far as operating conditions are concerned, moving the plasma source sufficiently far from the chamber entrance is shown to be a practical means for significantly reducing the density of the characteristic species of the early afterglow. Using the NO titration method, we obtain the (absolute) densities of N and O atoms in the afterglow at the NO injection inlet, a few cm before the chamber entrance: the N atom density goes through a maximum at approximately 0.3-0.5% O{sub 2} and then decreases, while the O atom density increases regularly with the O{sub 2} percentage. The spatial variation of the N atom (relative) density in the chamber is obtained by recording the emission intensity from the 1st positive system at 580 nm: in the 2-5 Torr range, this density is quite uniform everywhere in the chamber. The (relative

  2. NuSTAR OBSERVATIONS OF GRB 130427A ESTABLISH A SINGLE COMPONENT SYNCHROTRON AFTERGLOW ORIGIN FOR THE LATE OPTICAL TO MULTI-GEV EMISSION

    International Nuclear Information System (INIS)

    Kouveliotou, C.; Granot, J.; Racusin, J. L.; Gehrels, N.; McEnery, J. E.; Zhang, W. W.; Bellm, E.; Harrison, F. A.; Vianello, G.; Oates, S.; Fryer, C. L.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Dermer, C. D.; Hailey, C. J.; Melandri, A.; Tagliaferri, G.; Mundell, C. G.; Stern, D. K.

    2013-01-01

    GRB 130427A occurred in a relatively nearby galaxy; its prompt emission had the largest GRB fluence ever recorded. The afterglow of GRB 130427A was bright enough for the Nuclear Spectroscopic Telescope ARray (NuSTAR) to observe it in the 3-79 keV energy range long after its prompt emission (∼1.5 and 5 days). This range, where afterglow observations were previously not possible, bridges an important spectral gap. Combined with Swift, Fermi, and ground-based optical data, NuSTAR observations unambiguously establish a single afterglow spectral component from optical to multi-GeV energies a day after the event, which is almost certainly synchrotron radiation. Such an origin of the late-time Fermi/Large Area Telescope >10 GeV photons requires revisions in our understanding of collisionless relativistic shock physics

  3. Flowing afterglow: construction of an apparatus, measurement of rate constants, and consideration of the diffusive behavior of charges

    International Nuclear Information System (INIS)

    Matsuoka, Shingo; Nakamura, Hirone; Tamura, Takaaki; Fujii, Toshihiro.

    1984-01-01

    A flowing afterglow apparatus was constructed and the operation of the afterglow system including data analysis was tested by measuring the rate constants for the reactions N + + NO, N 2 + + NO, He + + N 2 , and SF 6 + e; the results were 5.8 x 10 -10 , 3.9 x 10 -10 , 1.20 x 10 -9 , and 2.1 x 10 -7 cm 3 s -1 respectively. In the measurements an extraction voltage for ion sampling was not applied to the nose cone in order not to introduce an electric field into the reaction region. A ''non-ambipolar'' model developed by us was used for the data analysis of the ion/molecule reactions. For the data analysis of the electron attachment, a typical curve fit mehtod to the product ion signal was used. However, no theoretical curves fit the experimental points. This disagreement is attributed to a change of the ion-sampling efficiency through the nose-cone aperture arising from a change of the electron-dominated plasma to a negative-ion-dominated plasma with an increasing flow rate of SF 6 . Nevertheless, the attachment rate could be determined by fitting the theoretical and experimantal curves in the limited region of the SF 6 flow rate where the negative-ion-dominated plasma is established at the sampling aperture. All the rate constants obtained here agree reasonably well with literature values. Next, errors in the positive ion/molecule reaction rate constants, which would occur if the diffusion coefficients of the ions and neutrals each have a + 10 % error were calculated for the flow model to be -0.4 and +1.2 % respectively, demonstrating that these parameters are not important in the analysis of data. This insensitivity explains why the nose-cone voltage applied in a typical flowing afterglow operation has not caused a significant error in the published rate constants although it disturbs the ion diffusive behavior. (author)

  4. A Large Catalog of Multiwavelength GRB Afterglows. I. Color Evolution and Its Physical Implication

    Science.gov (United States)

    Li, Liang; Wang, Yu; Shao, Lang; Wu, Xue-Feng; Huang, Yong-Feng; Zhang, Bing; Ryde, Felix; Yu, Hoi-Fung

    2018-02-01

    The spectrum of gamma-ray burst (GRB) afterglows can be studied with color indices. Here, we present a large comprehensive catalog of 70 GRBs with multiwavelength optical transient data on which we perform a systematic study to find the temporal evolution of color indices. We categorize them into two samples based on how well the color indices are evaluated. The Golden sample includes 25 bursts mostly observed by GROND, and the Silver sample includes 45 bursts observed by other telescopes. For the Golden sample, we find that 96% of the color indices do not vary over time. However, the color indices do vary during short periods in most bursts. The observed variations are consistent with effects of (i) the cooling frequency crossing the studied energy bands in a wind medium (43%) and in a constant-density medium (30%), (ii) early dust extinction (12%), (iii) transition from reverse-shock to forward-shock emission (5%), or (iv) an emergent SN emission (10%). We also study the evolutionary properties of the mean color indices for different emission episodes. We find that 86% of the color indices in the 70 bursts show constancy between consecutive ones. The color index variations occur mainly during the late GRB–SN bump, the flare, and early reverse-shock emission components. We further perform a statistical analysis of various observational properties and model parameters (spectral index {β }o{CI}, electron spectral indices p CI, etc.) using color indices. Overall, we conclude that ∼90% of colors are constant in time and can be accounted for by the simplest external forward-shock model, while the varying color indices call for more detailed modeling.

  5. GRB 080503 LATE AFTERGLOW RE-BRIGHTENING: SIGNATURE OF A MAGNETAR-POWERED MERGER-NOVA

    International Nuclear Information System (INIS)

    Gao, He; Ding, Xuan; Wu, Xue-Feng; Dai, Zi-Gao; Zhang, Bing

    2015-01-01

    GRB 080503 is a short gamma-ray burst (GRB) detected by Swift and has been classified as a GRB originating from a compact star merger. The soft extended emission and the simultaneous late re-brightening in both the X-ray and optical afterglow light curves raise interesting questions regarding its physical origin. We show that the broadband data of GRB 080503 can be well explained within the framework of the double neutron star merger model, provided that the merger remnant is a rapidly rotating massive neutron star with an extremely high magnetic field (i.e., a millisecond magnetar). We show that the late optical re-brightening is consistent with the emission from a magnetar-powered “merger-nova.” This adds one more case to the growing sample of merger-novae associated with short GRBs. The soft extended emission and the late X-ray excess emission are well connected through a magnetar dipole spin-down luminosity evolution function, suggesting that direct magnetic dissipation is the mechanism to produce these X-rays. The X-ray emission initially leaks from a hole in the merger ejecta pierced by the short GRB jet. The hole subsequently closes after the magnetar spins down and the magnetic pressure drops below ram pressure. The X-ray photons are then trapped behind the merger-nova ejecta until the ejecta becomes optically thin at a later time. This explains the essentially simultaneous re-brightening in both the optical and X-ray light curves. Within this model, future gravitational-wave sources could be associated with a bright X-ray counterpart along with the merger-nova, even if the short GRB jet beams away from Earth

  6. Measuring the beaming angle of GRB 030329 by fitting the rebrightenings in its multiband afterglow

    International Nuclear Information System (INIS)

    Deng Wei; Huang Yongfeng; Kong Siwei

    2010-01-01

    Multiple rebrightenings have been observed in the multiband afterglow of GRB 030329. In particular, a marked and quick rebrightening occurred at about t ∼ 1.2 x 10 5 s. Energy injection from late and slow shells seems to be the best interpretation for these rebrightenings. Usually it is assumed that the energy is injected into the whole external shock. However, in the case of GRB 030329, the rebrightenings are so quick that the usual consideration fails to give a satisfactory fit to the observed light curves. Actually, since these late/slow shells freely coast in the wake of the external shock, they should be cold and may not expand laterally. The energy injection then should only occur at the central region of the external shock. Considering this effect, we numerically re-fit the quick rebrightenings observed in GRB 030329. By doing this, we were able to derive the beaming angle of the energy injection process. Our result, with a relative residual of only 5% - 10% during the major rebrightening, is better than any previous modeling. The derived energy injection angle is about 0.035. We assume that these late shells are ejected by the central engine via the same mechanism as those early shells that produce the prompt gamma-ray burst. The main difference is that their velocities are much slower, so that they catch up with the external shock relatively late and are manifested as the observed quick rebrightenings. If this were true, then the derived energy injection angle can give a good measure of the beaming angle of the prompt γ-ray emission. Our study may hopefully provide a novel method to measure the beaming angle of gamma-ray bursts. (research papers)

  7. Spatio-temporal dynamics of a pulsed microwave argon plasma: ignition and afterglow

    International Nuclear Information System (INIS)

    Carbone, Emile; Sadeghi, Nader; Vos, Erik; Hübner, Simon; Van Veldhuizen, Eddie; Van Dijk, Jan; Nijdam, Sander; Kroesen, Gerrit

    2015-01-01

    In this paper, a detailed investigation of the spatio-temporal dynamics of a pulsed microwave plasma is presented. The plasma is ignited inside a dielectric tube in a repetitively pulsed regime at pressures ranging from 1 up to 100 mbar with pulse repetition frequencies from 200 Hz up to 500 kHz. Various diagnostic techniques are employed to obtain the main plasma parameters both spatially and with high temporal resolution. Thomson scattering is used to obtain the electron density and mean electron energy at fixed positions in the dielectric tube. The temporal evolution of the two resonant and two metastable argon 4s states are measured by laser diode absorption spectroscopy. Nanosecond time-resolved imaging of the discharge allows us to follow the spatio-temporal evolution of the discharge with high temporal and spatial resolution. Finally, the temporal evolution of argon 4p and higher states is measured by optical emission spectroscopy. The combination of these various diagnostics techniques gives deeper insight on the plasma dynamics during pulsed microwave plasma operation from low to high pressure regimes. The effects of the pulse repetition frequency on the plasma ignition dynamics are discussed and the plasma-off time is found to be the relevant parameter for the observed ignition modes. Depending on the delay between two plasma pulses, the dynamics of the ionization front are found to be changing dramatically. This is also reflected in the dynamics of the electron density and temperature and argon line emission from the plasma. On the other hand, the (quasi) steady state properties of the plasma are found to depend only weakly on the pulse repetition frequency and the afterglow kinetics present an uniform spatio-temporal behavior. However, compared to continuous operation, the time-averaged metastable and resonant state 4s densities are found to be significantly larger around a few kHz pulsing frequency. (paper)

  8. DISCOVERY AND REDSHIFT OF AN OPTICAL AFTERGLOW IN 71 deg{sup 2}: iPTF13bxl AND GRB 130702A

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Leo P.; Brown, Duncan A. [LIGO Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Bradley Cenko, S.; Gehrels, Neil; McEnery, Julie [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Kasliwal, Mansi M.; Mulchaey, John [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St, Pasadena, CA 91101 (United States); Perley, Daniel A.; Kulkarni, S. R.; Bellm, Eric; Barlow, Tom; Cao, Yi; Horesh, Assaf [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Ofek, Eran O.; Arcavi, Iair [Benoziyo Center for Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Nugent, Peter E.; Bloom, Joshua S. [Department of Astronomy, University of California Berkeley, B-20 Hearst Field Annex 3411, Berkeley, CA 94720-3411 (United States); Corsi, Alessandra [George Washington University, Corcoran Hall, Washington, DC 20052 (United States); Frail, Dale A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Masci, Frank J., E-mail: lsinger@caltech.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); and others

    2013-10-20

    We report the discovery of the optical afterglow of the γ-ray burst (GRB) 130702A, identified upon searching 71 deg{sup 2} surrounding the Fermi Gamma-ray Burst Monitor (GBM) localization. Discovered and characterized by the intermediate Palomar Transient Factory, iPTF13bxl is the first afterglow discovered solely based on a GBM localization. Real-time image subtraction, machine learning, human vetting, and rapid response multi-wavelength follow-up enabled us to quickly narrow a list of 27,004 optical transient candidates to a single afterglow-like source. Detection of a new, fading X-ray source by Swift and a radio counterpart by CARMA and the Very Large Array confirmed the association between iPTF13bxl and GRB 130702A. Spectroscopy with the Magellan and Palomar 200 inch telescopes showed the afterglow to be at a redshift of z = 0.145, placing GRB 130702A among the lowest redshift GRBs detected to date. The prompt γ-ray energy release and afterglow luminosity are intermediate between typical cosmological GRBs and nearby sub-luminous events such as GRB 980425 and GRB 060218. The bright afterglow and emerging supernova offer an opportunity for extensive panchromatic follow-up. Our discovery of iPTF13bxl demonstrates the first observational proof-of-principle for ∼10 Fermi-iPTF localizations annually. Furthermore, it represents an important step toward overcoming the challenges inherent in uncovering faint optical counterparts to comparably localized gravitational wave events in the Advanced LIGO and Virgo era.

  9. MODELING THE MULTI-BAND AFTERGLOW OF GRB 130831A: EVIDENCE FOR A SPINNING-DOWN MAGNETAR DOMINATED BY GRAVITATIONAL WAVE LOSSES?

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q.; Zong, H. S. [School of Physics, Nanjing University, Nanjing 210093 (China); Huang, Y. F., E-mail: zonghs@nju.edu.cn, E-mail: hyf@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2016-06-01

    The X-ray afterglow of GRB 130831A shows an “internal plateau” with a decay slope of ∼0.8, followed by a steep drop at around 10{sup 5} s with a slope of ∼6. After the drop, the X-ray afterglow continues with a much shallower decay. The optical afterglow exhibits two segments of plateaus separated by a luminous optical flare, followed by a normal decay with a slope basically consistent with that of the late-time X-ray afterglow. The decay of the internal X-ray plateau is much steeper than what we expect in the simplest magnetar model. We propose a scenario in which the magnetar undergoes gravitational-wave-driven r-mode instability, and the spin-down is dominated by gravitational wave losses up to the end of the steep plateau, so that such a relatively steep plateau can be interpreted as the internal emission of the magnetar wind and the sharp drop can be produced when the magnetar collapses into a black hole. This scenario also predicts an initial X-ray plateau lasting for hundreds of seconds with an approximately constant flux which is compatible with observation. Assuming that the magnetar wind has a negligible contribution in the optical band, we interpret the optical afterglow as the forward shock emission by invoking the energy injection from a continuously refreshed shock following the prompt emission phase. It is shown that our model can basically describe the temporal evolution of the multi-band afterglow of GRB 130831A.

  10. Characterization of the chlorophyll thermoluminescence afterglow in dark-adapted or far-red-illuminated plant leaves

    International Nuclear Information System (INIS)

    Miranda, T.; Ducruet, J.M.

    1995-01-01

    Far red illumination of photosynthetic material induces a delayed luminescence rise, or afterglow, which has been reported in plant leaves, protoplasts or intact chloroplasts and in algal cells. but does not occur in isolated thylakoids. The rise kinetics is accelerated by increasing temperature and we show, by slowly heating a leaf sample after a far-red illumination, that the afterglow emission can be optimally resolved as a sharp thermoluminescence band. Plant material was mainly pea (Pisum sativum L., cv Kazar and Merveille de Kelvedon) and cucumber (Cucumis sativus L., cv Marketer). Comparisons were done with rape, spinach, tobacco, avocado and maize. A 0.2 degree C-1s to 0.5 degree C-1s temperature gradient, started above 0 degree C after a far red illumination, revealed a new thermoluminescence AG band, peaking between 40 degree C and 50 degree C. It exhibited the characteristic properties of the luminescence afterglow recorded at a constant temperature. The AG band was very sensitive to short incubations at both freezing and moderately warm temperatures. Increasing duration of far red illumination caused two kinetically distinct effects on the AG band and on the B band (S-2S-3 Q-B- recombination), which can be ascribed to different behaviors of proton gradients in stroma and in grana lamellae, respectively. The induction of an afterglow by far red light lasted for several minutes in the dark, at 10 degree C. Flash sequences fired in these conditions confirmed the presence of S-2 and S-3 states stable in the dark, producing luminescence by recombination with back-transferred electrons. In some plant batches, an AG band could be induced by 2 or 3 flashes in the absence of far red light, which demonstrates that a metabolic state leading to AG emission may arise spontaneously in plant leaves. The strong temperature dependence of the AG emission is discussed in terms of heat-induced conformational changes in the thylakoid membrane. We conclude that

  11. The signature of supernova ejecta in the X-ray afterglow of the gamma-ray burst 011211.

    Science.gov (United States)

    Reeves, J N; Watson, D; Osborne, J P; Pounds, K A; O'Brien, P T; Short, A D T; Turner, M J L; Watson, M G; Mason, K O; Ehle, M; Schartel, N

    2002-04-04

    Now that gamma-ray bursts (GRBs) have been determined to lie at cosmological distances, their isotropic burst energies are estimated to be as high as 1054 erg (ref. 2), making them the most energetic phenomena in the Universe. The nature of the progenitors responsible for the bursts remains, however, elusive. The favoured models range from the merger of two neutron stars in a binary system to the collapse of a massive star. Spectroscopic studies of the afterglow emission could reveal details of the environment of the burst, by indicating the elements present, the speed of the outflow and an estimate of the temperature. Here we report an X-ray spectrum of the afterglow of GRB011211, which shows emission lines of magnesium, silicon, sulphur, argon, calcium and possibly nickel, arising in metal-enriched material with an outflow velocity of the order of one-tenth the speed of light. These observations strongly favour models where a supernova explosion from a massive stellar progenitor precedes the burst event and is responsible for the outflowing matter.

  12. Rapid formation of red long afterglow phosphor Sr3Al2O6:Eu2+, Dy3+ by microwave irradiation

    International Nuclear Information System (INIS)

    Zhang Ping; Xu Mingxia; Zheng Zhentai; Sun Bo; Zhang Yanhui

    2007-01-01

    A new red long afterglow phosphor Sr 3 Al 2 O 6 :Eu 2+ , Dy 3+ nanocrystalline particles were prepared using a microwave oven operated at a frequency of 2.45 GHz and a power of 680 W in a weak reductive atmosphere. The phosphor nanocrystalline particles were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The results reveal that the samples are composed of single Sr 3 Al 2 O 6 phase. The obtained nanocrystalline particles show small size (80-100 nm) and spherical shape. The excitation and emission spectra indicate that excitation broadband chiefly lies in visible range and the nanocrystalline particles emit strong light at 612 nm under around 473 nm excitation. The effect of Eu 2+ doping concentrations of the samples on the emission intensity is studied systematically. Furthermore, comparing with conventional heating method, the microwave method has the advantages such as short heating time and low energy consumption. However, the decay speed of the afterglow for Sr 3 Al 2 O 6 :Eu 2+ , Dy 3+ nanocrystalline particles is faster than that obtained by the conventional heating method

  13. Microplasma-based flowing atmospheric-pressure afterglow (FAPA) source for ambient desorption-ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zeiri, Offer M.; Storey, Andrew P.; Ray, Steven J., E-mail: sjray2@buffalo.edu; Hieftje, Gary M.

    2017-02-01

    A new direct-current microplasma-based flowing atmospheric pressure afterglow (FAPA) source was developed for use in ambient desorption-ionization mass spectrometry. The annular-shaped microplasma is formed in helium between two concentric stainless-steel capillaries that are separated by an alumina tube. Current-voltage characterization of the source shows that this version of the FAPA operates in the normal glow-discharge regime. A glass surface placed in the path of the helium afterglow reaches temperatures of up to approximately 400 °C; the temperature varies with distance from the source and helium flow rate through the source. Solid, liquid, and vapor samples were examined by means of a time-of-flight mass spectrometer. Results suggest that ionization occurs mainly through protonation, with only a small amount of fragmentation and adduct formation. The mass range of the source was shown to extend up to at least m/z 2722 for singly charged species. Limits of detection for several small organic molecules were in the sub-picomole range. Examination of competitive ionization revealed that signal suppression occurs only at high (mM) concentrations of competing substances. - Highlights: • The first microplasma version of the FAPA source. • Current-voltage behavior reflects the behavior of a normal glow discharge. • Detection limits below 1 pmol for the classes of organic compounds studied over a wide mass range. • Mass spectra show limited fragmentation.

  14. Electron energy distribution function, effective electron temperature, and dust charge in the temporal afterglow of a plasma

    International Nuclear Information System (INIS)

    Denysenko, I. B.; Azarenkov, N. A.; Kersten, H.

    2016-01-01

    Analytical expressions describing the variation of electron energy distribution function (EEDF) in an afterglow of a plasma are obtained. Especially, the case when the electron energy loss is mainly due to momentum-transfer electron-neutral collisions is considered. The study is carried out for different EEDFs in the steady state, including Maxwellian and Druyvesteyn distributions. The analytical results are not only obtained for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy but also for the case when the collisions are a power function of electron energy. Using analytical expressions for the EEDF, the effective electron temperature and charge of the dust particles, which are assumed to be present in plasma, are calculated for different afterglow durations. An analytical expression for the rate describing collection of electrons by dust particles for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy is also derived. The EEDF profile and, as a result, the effective electron temperature and dust charge are sufficiently different in the cases when the rate for momentum-transfer electron-neutral collisions is independent on electron energy and when the rate is a power function of electron energy.

  15. EARLY AFTERGLOWS OF GAMMA-RAY BURSTS IN A STRATIFIED MEDIUM WITH A POWER-LAW DENSITY DISTRIBUTION

    International Nuclear Information System (INIS)

    Yi, Shuang-Xi; Dai, Zi-Gao; Wu, Xue-Feng

    2013-01-01

    A long-duration gamma-ray burst (GRB) has been widely thought to arise from the collapse of a massive star, and it has been suggested that its ambient medium is a homogenous interstellar medium (ISM) or a stellar wind. There are two shocks when an ultra-relativistic fireball that has been ejected during the prompt gamma-ray emission phase sweeps up the circumburst medium: a reverse shock that propagates into the fireball, and a forward shock that propagates into the ambient medium. In this paper, we investigate the temporal evolution of the dynamics and emission of these two shocks in an environment with a general density distribution of n∝R –k (where R is the radius) by considering thick-shell and thin-shell cases. A GRB afterglow with one smooth onset peak at early times is understood to result from such external shocks. Thus, we can determine the medium density distribution by fitting the onset peak appearing in the light curve of an early optical afterglow. We apply our model to 19 GRBs and find that their k values are in the range of 0.4-1.4, with a typical value of k ∼ 1, implying that this environment is neither a homogenous ISM with k = 0 nor a typical stellar wind with k = 2. This shows that the progenitors of these GRBs might have undergone a new mass-loss evolution

  16. THE NEEDLE IN THE 100 deg{sup 2} HAYSTACK: UNCOVERING AFTERGLOWS OF FERMI GRBs WITH THE PALOMAR TRANSIENT FACTORY

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Leo P. [LIGO Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Kasliwal, Mansi M. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena CA 91101 (United States); Cenko, S. Bradley; Cucchiara, Antonino; Gehrels, Neil [Astrophysics Science Division, NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Perley, Daniel A.; Cao, Yi [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Anderson, Gemma E.; Fender, Rob P. [Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Anupama, G. C. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Arcavi, Iair [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Bhalerao, Varun [Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, Pune 411007 (India); Bue, Brian D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Connaughton, Valerie [CSPAR and Physics Department, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Corsi, Alessandra [Texas Tech University, Physics Department, Lubbock, TX 79409-1051 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Goldstein, Adam [Astrophysics Office, ZP12, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gorosabel, J. [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Horesh, Assaf, E-mail: leo.p.singer@nasa.gov [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); and others

    2015-06-10

    The Fermi Gamma-ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi GRB Monitor instrument have posed a formidable obstacle to locating the bursts’ host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target-of-opportunity mode for the intermediate Palomar Transient Factory in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: 8 afterglow discoveries out of 35 searches. Two of the bursts with detected afterglows (GRBs 130702A and 140606B) were at low redshift (z = 0.145 and 0.384, respectively) and had spectroscopically confirmed broad-line Type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samples. We identify one new outlier on the Amati relation. We find that two bursts are consistent with a mildly relativistic shock breaking out from the progenitor star rather than the ultra-relativistic internal shock mechanism that powers standard cosmological bursts. Finally, in the context of the Zwicky Transient Facility, we discuss how we will continue to expand this effort to find optical counterparts of binary neutron star mergers that may soon be detected by Advanced LIGO and Virgo.

  17. NuSTARobservations of grb 130427a establish a single component synchrotron afterglow origin for the late optical to multi-gev emission

    DEFF Research Database (Denmark)

    Kouveliotou, C.; Granot, J.; Racusin, J. L.

    2013-01-01

    GRB 130427A occurred in a relatively nearby galaxy; its prompt emission had the largest GRB fluence ever recorded. The afterglow of GRB 130427A was bright enough for the Nuclear Spectroscopic Telescope ARray (NuSTAR) to observe it in the 3-79 keV energy range long after its prompt emission (simil...

  18. Detailed optical and near-infrared polarimetry, spectroscopy and broad-band photometry of the afterglow of GRB 091018: polarization evolution

    NARCIS (Netherlands)

    Wiersema, K.; Curran, P.; Krühler, T.; Melandri, A.; Rol, E.; Starling, R.L.C.; Tanvir, N.R.; van der Horst, A.J.; Covino, S.; Fynbo, J.P.U.; Goldoni, P.; Gorosabel, J.; Hjorth, J.; Klose, S.; Mundell, C.G.; O'Brien, P.T.; Palazzi, E.; Wijers, R.A.M.J.; D'Elia, V.; Evans, P.A.; Filgas, R.; Gomboc, A.; Greiner, J.; Guidorzi, C.; Kaper, L.; Kobayashi, S.; Kouveliotou, C.; Levan, A.J.; Rossi, A..; Rowlinson, A.; Steele, I.A.; de Ugarte Postigo, A.; Vergani, S.D.

    2012-01-01

    Follow-up observations of large numbers of gamma-ray burst (GRB) afterglows, facilitated by the Swift satellite, have produced a large sample of spectral energy distributions and light curves, from which their basic micro- and macro-physical parameters can in principle be derived. However, a number

  19. AFTERGLOW OBSERVATIONS OF FERMI LARGE AREA TELESCOPE GAMMA-RAY BURSTS AND THE EMERGING CLASS OF HYPER-ENERGETIC EVENTS

    International Nuclear Information System (INIS)

    Cenko, S. B.; Butler, N. R.; Cobb, B. E.; Cucchiara, A.; Bloom, J. S.; Perley, D. A.; Filippenko, A. V.; Frail, D. A.; Harrison, F. A.; Haislip, J. B.; Reichart, D. E.; Ivarsen, K. M.; LaCluyze, A. P.; Berger, E.; Chandra, P.; Fox, D. B.; Prochaska, J. X.; Glazebrook, K.; Kasliwal, M. M.; Kulkarni, S. R.

    2011-01-01

    We present broadband (radio, optical, and X-ray) light curves and spectra of the afterglows of four long-duration gamma-ray bursts (GRBs; GRBs 090323, 090328, 090902B, and 090926A) detected by the Gamma-Ray Burst Monitor and Large Area Telescope (LAT) instruments on the Fermi satellite. With its wide spectral bandpass, extending to GeV energies, Fermi is sensitive to GRBs with very large isotropic energy releases (10 54 erg). Although rare, these events are particularly important for testing GRB central-engine models. When combined with spectroscopic redshifts, our afterglow data for these four events are able to constrain jet collimation angles, the density structure of the circumburst medium, and both the true radiated energy release and the kinetic energy of the outflows. In agreement with our earlier work, we find that the relativistic energy budget of at least one of these events (GRB 090926A) exceeds the canonical value of 10 51 erg by an order of magnitude. Such energies pose a severe challenge for models in which the GRB is powered by a magnetar or a neutrino-driven collapsar, but remain compatible with theoretical expectations for magnetohydrodynamical collapsar models (e.g., the Blandford-Znajek mechanism). Our jet opening angles (θ) are similar to those found for pre-Fermi GRBs, but the large initial Lorentz factors (Γ 0 ) inferred from the detection of GeV photons imply θΓ 0 ∼ 70-90, values which are above those predicted in magnetohydrodynamic models of jet acceleration. Finally, we find that these Fermi-LAT events preferentially occur in a low-density circumburst environment, and we speculate that this might result from the lower mass-loss rates of their lower-metallicity progenitor stars. Future studies of Fermi-LAT afterglows at radio wavelengths with the order-of-magnitude improvement in sensitivity offered by the Extended Very Large Array should definitively establish the relativistic energy budgets of these events.

  20. HELIUM IN NATAL H II REGIONS: THE ORIGIN OF THE X-RAY ABSORPTION IN GAMMA-RAY BURST AFTERGLOWS

    International Nuclear Information System (INIS)

    Watson, Darach; Andersen, Anja C.; Fynbo, Johan P. U.; Hjorth, Jens; Krühler, Thomas; Laursen, Peter; Leloudas, Giorgos; Malesani, Daniele; Zafar, Tayyaba; Gorosabel, Javier; Jakobsson, Páll

    2013-01-01

    Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that absorption by He in the GRB's host H II region is responsible for most of the absorption. We show that the X-ray absorbing column density (N H X ) is correlated with both the neutral gas column density and with the optical afterglow's dust extinction (A V ). This correlation explains the connection between dark bursts and bursts with high N H X values. From these correlations, we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e., the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this, we conclude that the column density of the X-ray absorption is correlated with the total gas column density in the host galaxy rather than the metal column density, in spite of the fact that X-ray absorption is typically dominated by metals. The strong redshift evolution of N H X /A V is thus a reflection of the cosmic metallicity evolution of star-forming galaxies and we find it to be consistent with measurements of the redshift evolution of metallicities for GRB host galaxies. We conclude that the absorption of X-rays in GRB afterglows is caused by He in the H II region hosting the GRB. While dust is destroyed and metals are stripped of all of their electrons by the GRB to great distances, the abundance of He saturates the He-ionizing UV continuum much closer to the GRB, allowing it to remain in the neutral or singly-ionized state. Helium X-ray absorption explains the correlation with total gas, the lack of strong evolution with redshift, as well as the absence of dust, metal or

  1. Wide field X-ray telescopes: Detecting X-ray transients/afterglows related to gamma ray bursts

    International Nuclear Information System (INIS)

    Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul; Rezek, Tomas

    1999-01-01

    The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited field of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70ies but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster eye type are presented and discussed. Optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

  2. FAST RADIO BURSTS AND THEIR GAMMA-RAY OR RADIO AFTERGLOWS AS KERR–NEWMAN BLACK HOLE BINARIES

    International Nuclear Information System (INIS)

    Liu, Tong; Li, Ang; Romero, Gustavo E.; Liu, Mo-Lin

    2016-01-01

    Fast radio bursts (FRBs) are radio transients lasting only about a few milliseconds. They seem to occur at cosmological distances. We propose that these events can originate in the collapse of the magnetospheres of Kerr–Newman black holes (KNBHs). We show that the closed orbits of charged particles in the magnetospheres of these objects are unstable. After examining the dependencies on the specific charge of the particle and the spin and charge of the KNBH, we conclude that the resulting timescale and radiation mechanism fit well with extant observations of FRBs. Furthermore, we argue that the merger of a KNBH binary is a plausible central engine for the potential gamma-ray or radio afterglow following certain FRBs and can also account for gravitational wave (GW) events like GW 150914. Our model leads to predictions that can be tested by combined multi-wavelength electromagnetic and GW observations.

  3. Inactivation of Candida glabrata by a humid DC argon discharge afterglow: dominant contributions of short-lived aqueous active species

    International Nuclear Information System (INIS)

    Xiong, Qing; Liu, Hongbin; Xu, Le; Wang, Xia; Zhu, Qunlin; Lu, Weiping; Chen, Qiang; Zeng, Xue; Yi, Ping

    2017-01-01

    Plasma medicine applications are currently attracting significant interest all over the world. Bactericidal treatments of Candida glabrata cultured in saline suspension are performed in this study by a room-temperature reactive afterglow of a DC-driven argon discharge. Water vapor was added to the discharge to study the inactivation contributions of reactive hydrolytic species including OH and H 2 O 2 transporting along the gas flow to the treated solutions. The inactivation results indicate that the dominant roles in the bactericidal treatments are played by the short-lived aqueous active species, but not the stable species like H 2 O 2aq (aq indicates an aqueous species). Further analysis shows that the ·OH aq radicals play an important role in the inactivation process. The ·OH aq radicals in the suspension are mostly produced from the direct dissolution of the OH species in the reactive afterglow. With the increase of added water vapor content, the ·OH aq production increases and enhances the inactivation efficiency of C. glabrata . Furthermore, it is found that the ambient air diffusion shows essential effects on the bactericidal activity of the remote humid argon discharge. Higher bactericidal effects can be obtained in open-space treatments compared to in a controlled Ar + H 2 O gas atmosphere. Key active air-byproduct species are believed to be generated in the suspension during the treatments and contributing to the inactivation process. Based on chemical analysis, the peroxynitrous acid ONOOH aq is considered as the key antimicrobial air-byproduct species. These results indicate the important dependence of plasma biomedical effects on the processing environment, which finally relates to the critical contributions of the key reactive species formed therein. (paper)

  4. Temporal evolution of electron energy distribution function and plasma parameters in the afterglow of drifting magnetron plasma

    International Nuclear Information System (INIS)

    Seo, Sang-Hun; In, Jung-Hwan; Chang, Hong-Young

    2005-01-01

    The temporal behaviour of the electron energy distribution function (EEDF) and the plasma parameters such as electron density, electron temperature and plasma and floating potentials in a mid-frequency pulsed dc magnetron plasma are investigated using time-resolved probe measurements. A negative-voltage dc pulse with an average power of 160 W during the pulse-on period, a repetition frequency of 20 kHz and a duty cycle of 50% is applied to the cathode of a planar unbalanced magnetron discharge with a grounded substrate. The measured electron energy distribution is found to exhibit a bi-Maxwellian distribution, which can be resolved with the low-energy electron group and the high-energy tail part during the pulse-on period, and a Maxwellian distribution only with low-energy electrons as a consequence of initially rapid decay of the high-energy tail part during the pulse-off period. This characteristic evolution of the EEDF is reflected in the decay characteristics of the electron density and temperature in the afterglow. These parameters exhibit twofold decay represented by two characteristic decay times of an initial fast decay time τ 1 , and a subsequent slower decay time τ 2 in the afterglow when approximated with a bi-exponential function. While the initial fast decay times are of the order of 1 μs (τ T1 ∼ 0.99 μs and τ N1 ∼ 1.5 μs), the slower decay times are of the order of a few tens of microseconds (τ T2 ∼ 7 μs and τ N2 ∼ 40 μs). The temporal evolution of the plasma parameters are qualitatively explained by considering the formation mechanism of the bi-Maxwellian electron distribution function and the electron transports of these electron groups in bulk plasma

  5. Inactivation of Candida glabrata by a humid DC argon discharge afterglow: dominant contributions of short-lived aqueous active species

    Science.gov (United States)

    Xiong, Qing; Liu, Hongbin; Lu, Weiping; Chen, Qiang; Xu, Le; Wang, Xia; Zhu, Qunlin; Zeng, Xue; Yi, Ping

    2017-05-01

    Plasma medicine applications are currently attracting significant interest all over the world. Bactericidal treatments of Candida glabrata cultured in saline suspension are performed in this study by a room-temperature reactive afterglow of a DC-driven argon discharge. Water vapor was added to the discharge to study the inactivation contributions of reactive hydrolytic species including OH and H2O2 transporting along the gas flow to the treated solutions. The inactivation results indicate that the dominant roles in the bactericidal treatments are played by the short-lived aqueous active species, but not the stable species like H2O2aq (aq indicates an aqueous species). Further analysis shows that the ·OHaq radicals play an important role in the inactivation process. The ·OHaq radicals in the suspension are mostly produced from the direct dissolution of the OH species in the reactive afterglow. With the increase of added water vapor content, the ·OHaq production increases and enhances the inactivation efficiency of C. glabrata. Furthermore, it is found that the ambient air diffusion shows essential effects on the bactericidal activity of the remote humid argon discharge. Higher bactericidal effects can be obtained in open-space treatments compared to in a controlled Ar + H2O gas atmosphere. Key active air-byproduct species are believed to be generated in the suspension during the treatments and contributing to the inactivation process. Based on chemical analysis, the peroxynitrous acid ONOOHaq is considered as the key antimicrobial air-byproduct species. These results indicate the important dependence of plasma biomedical effects on the processing environment, which finally relates to the critical contributions of the key reactive species formed therein.

  6. Kinetic study on non-thermal volumetric plasma decay in the early afterglow of air discharge generated by a short pulse microwave or laser

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wei, E-mail: yangwei861212@126.com; Zhou, Qianhong; Dong, Zhiwei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

    2016-08-28

    This paper reports a kinetic study on non-thermal plasma decay in the early afterglow of air discharge generated by short pulse microwave or laser. A global self-consistent model is based on the particle balance of complex plasma chemistry, electron energy equation, and gas thermal balance equation. Electron-ion Coulomb collision is included in the steady state Boltzmann equation solver to accurately describe the electron mobility and other transport coefficients. The model is used to simulate the afterglow of microsecond to nanosecond pulse microwave discharge in N{sub 2}, O{sub 2}, and air, as well as femtosecond laser filament discharge in dry and humid air. The simulated results for electron density decay are in quantitative agreement with the available measured ones. The evolution of plasma decay under an external electric field is also investigated, and the effect of gas heating is considered. The underlying mechanism of plasma density decay is unveiled through the above kinetic modeling.

  7. On-line Determination of the Deuterium Abundance in Breath Water Vapour by Flowing Afterglow Mass Spectrometry with Applications to Measurements of Total Body Water

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Smith, D.

    2001-01-01

    Roč. 15, č. 1 (2001), s. 25-32 ISSN 0951-4198 R&D Project s: GA ČR GA203/00/0632 Grant - others:Royal Society(GB) Joint project Institutional research plan: CEZ:AV0Z4040901 Keywords : flowing afterglow * mass spectrometry * stable isotopes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.478, year: 2001

  8. iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-Energy Trigger

    Science.gov (United States)

    Cenko, S. Bradley; Urban, Alex L.; Perley, Daniel A.; Horesh, Assaf; Corsi, Alessandra; Fox, Derek B.; Cao, Yi; Kasliwal, Mansi M.; Lien, Amy; Arcavi, Iair; hide

    2015-01-01

    We report here the discovery by the Intermediate Palomar Transient Factory (iPTF) of iPTF14yb, a luminous (Mr >> -27.8 mag), cosmological (redshift 1.9733), rapidly fading optical transient. We demonstrate, based on probabilistic arguments and a comparison with the broader population, that iPTF14yb is the optical afterglow of the long-duration gamma-ray burst GRB 140226A. This marks the first unambiguous discovery of a GRB afterglow prior to (and thus entirely independent of) an associated high-energy trigger. We estimate the rate of iPTF14yb-like sources (i.e., cosmologically distant relativistic explosions) based on iPTF observations, inferring an all-sky value of Rrel = 610/yr (68% confidence interval of 110-2000/yr). Our derived rate is consistent (within the large uncertainty) with the all-sky rate of on-axis GRBs derived by the Swift satellite. Finally, we briefly discuss the implications of the nondetection to date of bona fide "orphan" afterglows (i.e., those lacking detectable high-energy emission) on GRB beaming and the degree of baryon loading in these relativistic jets.

  9. Modeling the Multiband Afterglows of GRB 060614 and GRB 060908: Further Evidence for a Double Power-law Hard Electron Energy Spectrum

    Science.gov (United States)

    Zhang, Q.; Xiong, S. L.; Song, L. M.

    2018-04-01

    Electrons accelerated in relativistic collisionless shocks are usually assumed to follow a power-law energy distribution with an index of p. Observationally, although most gamma-ray bursts (GRBs) have afterglows that are consistent with p > 2, there are still a few GRBs suggestive of a hard (p law hard electron energy (DPLH) spectrum with 1 2 and an “injection break” assumed as γ b ∝ γ q in the highly relativistic regime, where γ is the bulk Lorentz factor of the jet. In this paper, we show that GRB 060614 and GRB 060908 provide further evidence for such a DPLH spectrum. We interpret the multiband afterglow of GRB 060614 with the DPLH model in a homogeneous interstellar medium by taking into account a continuous energy injection process, while, for GRB 060908, a wind-like circumburst density profile is used. The two bursts, along with GRB 091127, suggest a similar behavior in the evolution of the injection break, with q ∼ 0.5. Whether this represents a universal law of the injection break remains uncertain and more afterglow observations such as these are needed to test this conjecture.

  10. THERMAL EMISSION IN THE EARLY X-RAY AFTERGLOWS OF GAMMA-RAY BURSTS: FOLLOWING THE PROMPT PHASE TO LATE TIMES

    Energy Technology Data Exchange (ETDEWEB)

    Friis, Mette [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Watson, Darach, E-mail: mef4@hi.is, E-mail: darach@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark)

    2013-07-01

    Thermal radiation, peaking in soft X-rays, has now been detected in a handful of gamma-ray burst (GRB) afterglows and has to date been interpreted as shock break-out of the GRB's progenitor star. We present a search for thermal emission in the early X-ray afterglows of a sample of Swift bursts selected by their brightness in X-rays at early times. We identify a clear thermal component in eight GRBs and track the evolution. We show that at least some of the emission must come from highly relativistic material since two show an apparent super-luminal expansion of the thermal component. Furthermore, we determine very large luminosities and high temperatures for many of the components-too high to originate in a supernova shock break-out. Instead, we suggest that the component may be modeled as late photospheric emission from the jet, linking it to the apparently thermal component observed in the prompt emission of some GRBs at gamma-ray and hard X-ray energies. By comparing the parameters from the prompt emission and the early afterglow emission, we find that the results are compatible with the interpretation that we are observing the prompt quasi-thermal emission component in soft X-rays at a later point in its evolution.

  11. Constraining Gamma-ray Burst Initial Lorentz Factor with the Afterglow Onset Feature and Discovery of a Tight Γ0-E γ,iso Correlation

    Science.gov (United States)

    Liang, En-Wei; Yi, Shuang-Xi; Zhang, Jin; Lü, Hou-Jun; Zhang, Bin-Bin; Zhang, Bing

    2010-12-01

    The onset of gamma-ray burst (GRB) afterglow is characterized by a smooth bump in the early afterglow light curve as the GRB fireball is decelerated by the circumburst medium. We extensively search for GRBs with such an onset feature in their optical and X-ray light curves from the literature and from the catalog established with the Swift/XRT. Twenty optically selected GRBs and 12 X-ray-selected GRBs are obtained, among which 17 optically selected and 2 X-ray-selected GRBs have redshift measurements. We fit these light curves with a smooth broken power law and measure the width (w), rising timescale (t r), and decaying timescale (t d) at full width at half-maximum. Strong mutual correlations among these timescales and with the peak time (t p) are found. The ratio t r/t d is almost universal among bursts, but the ratio t r/t p varies from 0.3 to ~1. The optical peak luminosity in the R band (L R,p) is anti-correlated with t p and w in the burst frame, indicating a dimmer and broader bump peaking at a later time. The isotropic prompt gamma-ray energy (E γ,iso) is also tightly correlated with L R,p and t p in the burst frame. Assuming that the bumps signal the deceleration of the GRB fireballs in a constant density medium, we calculate the initial Lorentz factor (Γ0) and the deceleration radius (R d) of the GRBs with redshift measurements. The derived Γ0 is typically a few hundreds, and the deceleration radius is R dec ~ 2 × 1017 cm. More intriguingly, a tight correlation between Γ0 and E γ,iso is found, namely Γ0 ~= 182(E γ,iso/1052 erg)0.25. This correlation also applies to the small sample of GRBs which show the signature of the afterglow onset in their X-ray afterglow, and to two bursts (GRBs 990123 and 080319B) whose early optical emission is dominated by a reverse shock. The lower limits of Γ0 derived from a sample of optical afterglow light curves showing a decaying feature from the beginning of the observation are also generally consistent with such

  12. An optical spectrum of the afterglow of a gamma-ray burst at a redshift of z = 6.295.

    Science.gov (United States)

    Kawai, N; Kosugi, G; Aoki, K; Yamada, T; Totani, T; Ohta, K; Iye, M; Hattori, T; Aoki, W; Furusawa, H; Hurley, K; Kawabata, K S; Kobayashi, N; Komiyama, Y; Mizumoto, Y; Nomoto, K; Noumaru, J; Ogasawara, R; Sato, R; Sekiguchi, K; Shirasaki, Y; Suzuki, M; Takata, T; Tamagawa, T; Terada, H; Watanabe, J; Yatsu, Y; Yoshida, A

    2006-03-09

    The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.

  13. Influence of gas and treatment time on the surface modification of EPDM rubber treated at afterglow microwave plasmas

    Science.gov (United States)

    da Maia, J. V.; Pereira, F. P.; Dutra, J. C. N.; Mello, S. A. C.; Becerra, E. A. O.; Massi, M.; Sobrinho, A. S. da Silva

    2013-11-01

    The ethylene propylene diene monomer (EPDM) rubber possesses excellent physical/chemical bulk properties, is cost-effective, and has been used in the mechanical and aerospace industry. However, it has an inert surface and needs a surface treatment in order to improve its adhesion properties. Plasma modification is the most accepted technique for surface modification of polymers without affecting the properties of the bulk. In this study, an afterglow microwave plasma reactor was used to generate the plasma species responsible for the EPDM surface modification. The plasma modified surfaces were analyzed by means of contact angle measurement, adhesion tests, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. Two experimental variables were analyzed: type of the plasma gases and exposure time were considered. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed and the best conditions tested there was an increase of the rupture strength of about 27%, that can be associated mainly with the creation of oxygen containing functional groups on the rubber surface (CO, COC and CO) identified by spectroscopic methods. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed. In various conditions tested the contact angles easily decreased more than 500%. What can be concluded that high wettability is a necessary condition to obtain good adhesion, but this is not a sufficient condition.

  14. Influence of gas and treatment time on the surface modification of EPDM rubber treated at afterglow microwave plasmas

    International Nuclear Information System (INIS)

    Maia, J.V. da; Pereira, F.P.; Dutra, J.C.N.; Mello, S.A.C.; Becerra, E.A.O.; Massi, M.; Sobrinho, A.S. da Silva

    2013-01-01

    The ethylene propylene diene monomer (EPDM) rubber possesses excellent physical/chemical bulk properties, is cost-effective, and has been used in the mechanical and aerospace industry. However, it has an inert surface and needs a surface treatment in order to improve its adhesion properties. Plasma modification is the most accepted technique for surface modification of polymers without affecting the properties of the bulk. In this study, an afterglow microwave plasma reactor was used to generate the plasma species responsible for the EPDM surface modification. The plasma modified surfaces were analyzed by means of contact angle measurement, adhesion tests, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. Two experimental variables were analyzed: type of the plasma gases and exposure time were considered. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed and the best conditions tested there was an increase of the rupture strength of about 27%, that can be associated mainly with the creation of oxygen containing functional groups on the rubber surface (C-O, C-O-C and C=O) identified by spectroscopic methods. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed. In various conditions tested the contact angles easily decreased more than 500%. What can be concluded that high wettability is a necessary condition to obtain good adhesion, but this is not a sufficient condition.

  15. Influence of gas and treatment time on the surface modification of EPDM rubber treated at afterglow microwave plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Maia, J.V. da, E-mail: jaisondamaia@hotmail.com [Plasmas and Processes Laboratory, Department of Physics, Technological Institute of Aeronautics, 12228-900 S. J. dos Campos, SP (Brazil); Department of Physics, Federal Institute of Santa Catarina, 89251-000 Jaraguá do Sul, SC (Brazil); Pereira, F.P. [Plasmas and Processes Laboratory, Department of Physics, Technological Institute of Aeronautics, 12228-900 S. J. dos Campos, SP (Brazil); Dutra, J.C.N.; Mello, S.A.C. [EBO, Chemistry Division, IAE, CTA, 12228-900 S. J. dos Campos, SP (Brazil); Becerra, E.A.O. [Department of Physics, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Massi, M.; Sobrinho, A.S. da Silva [Plasmas and Processes Laboratory, Department of Physics, Technological Institute of Aeronautics, 12228-900 S. J. dos Campos, SP (Brazil)

    2013-11-15

    The ethylene propylene diene monomer (EPDM) rubber possesses excellent physical/chemical bulk properties, is cost-effective, and has been used in the mechanical and aerospace industry. However, it has an inert surface and needs a surface treatment in order to improve its adhesion properties. Plasma modification is the most accepted technique for surface modification of polymers without affecting the properties of the bulk. In this study, an afterglow microwave plasma reactor was used to generate the plasma species responsible for the EPDM surface modification. The plasma modified surfaces were analyzed by means of contact angle measurement, adhesion tests, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. Two experimental variables were analyzed: type of the plasma gases and exposure time were considered. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed and the best conditions tested there was an increase of the rupture strength of about 27%, that can be associated mainly with the creation of oxygen containing functional groups on the rubber surface (C-O, C-O-C and C=O) identified by spectroscopic methods. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed. In various conditions tested the contact angles easily decreased more than 500%. What can be concluded that high wettability is a necessary condition to obtain good adhesion, but this is not a sufficient condition.

  16. Two-photon absorption laser-induced fluorescence of atomic oxygen in the afterglow of pulsed positive corona discharge

    Science.gov (United States)

    Ono, Ryo; Takezawa, Kei; Oda, Tetsuji

    2009-08-01

    Atomic oxygen is measured in the afterglow of pulsed positive corona discharge using time-resolved two-photon absorption laser-induced fluorescence. The discharge occurs in a 14 mm point-to-plane gap in dry air. After the discharge pulse, the atomic oxygen density decreases at a rate of 5×104 s-1. Simultaneously, ozone density increases at almost the same rate, where the ozone density is measured using laser absorption method. This agreement between the increasing rate of atomic oxygen and decreasing rate of ozone proves that ozone is mainly produced by the well-known three-body reaction, O+O2+M→O3+M. No other process for ozone production such as O2(v)+O2→O3+O is observed. The spatial distribution of atomic oxygen density is in agreement with that of the secondary streamer luminous intensity. This agreement indicates that atomic oxygen is mainly produced in the secondary streamer channels, not in the primary streamer channels.

  17. Rapid temperature increase near the anode and cathode in the afterglow of a pulsed positive streamer discharge

    Science.gov (United States)

    Ono, Ryo

    2018-06-01

    The spatiotemporal evolution of the temperature in the afterglow of point-to-plane, pulsed positive streamer discharge was measured near the anode tip and cathode surface using laser-induced predissociation fluorescence of OH radicals. The temperature exhibited a rapid increase and displayed a steep spatial gradient after a discharge pulse. The rate of temperature rise reached 84 K μs‑1 at mm, where z represents the distance from the anode tip. The temperature rise was much faster than in the middle of the gap; it was only 2.8 K μs‑1 at mm. The temperature reached 1700 K near the anode tip at s and 1500 K near the cathode surface at s, where t represents the postdischarge time. The spatial gradient reached 1280 K mm‑1 near the anode tip at s. The mechanism responsible for the rapid temperature increase was discussed, including rapid heating of the gas in the early postdischarge phase (s), and vibration-to-translation energy transfer in the later postdischarge phase (s). The high temperatures near the anode tip and cathode surface are particularly important for the ignition of combustible mixtures and for surface treatments, including solid-surface treatments, water treatments, and plasma medicine using pulsed streamer discharges.

  18. DETERMINATION OF THE INTRINSIC LUMINOSITY TIME CORRELATION IN THE X-RAY AFTERGLOWS OF GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Dainotti, Maria Giovanna; Petrosian, Vahe'; Singal, Jack; Ostrowski, Michal

    2013-01-01

    Gamma-ray bursts (GRBs), which have been observed up to redshifts z ≈ 9.5, can be good probes of the early universe and have the potential to test cosmological models. Dainotti's analysis of GRB Swift afterglow light curves with known redshifts and a definite X-ray plateau shows an anti-correlation between the rest-frame time when the plateau ends (the plateau end time) and the calculated luminosity at that time (or approximately an anti-correlation between plateau duration and luminosity). Here, we present an update of this correlation with a larger data sample of 101 GRBs with good light curves. Since some of this correlation could result from the redshift dependences of these intrinsic parameters, namely, their cosmological evolution, we use the Efron-Petrosian method to reveal the intrinsic nature of this correlation. We find that a substantial part of the correlation is intrinsic and describe how we recover it and how this can be used to constrain physical models of the plateau emission, the origin of which is still unknown. The present result could help to clarify the debated nature of the plateau emission

  19. EARLY-TIME VLA OBSERVATIONS AND BROADBAND AFTERGLOW ANALYSIS OF THE FERMI/LAT DETECTED GRB 130907A

    International Nuclear Information System (INIS)

    Veres, Péter; Corsi, Alessandra; Frail, Dale A.; Cenko, S. Bradley; Perley, Daniel A.

    2015-01-01

    We present multi-wavelength observations of the hyper-energetic gamma-ray burst (GRB) 130907A, a Swift-discovered burst with early radio observations starting at ≈4 hr after the γ-ray trigger. GRB 130907A was also detected by the Fermi/LAT instrument and at late times showed a strong spectral evolution in X-rays. We focus on the early-time radio observations, especially at >10 GHz, to attempt to identify reverse shock signatures. While our radio follow-up of GRB 130907A ranks among the earliest observations of a GRB with the Karl G. Jansky Very Large Array, we did not see an unambiguous signature of a reverse shock. While a model with both reverse and forward shock can correctly describe the observations, the data is not constraining enough to decide upon the presence of the reverse-shock component. We model the broadband data using a simple forward-shock synchrotron scenario with a transition from a wind environment to a constant density interstellar medium (ISM) in order to account for the observed features. Within the confines of this model, we also derive the underlying physical parameters of the fireball, which are within typical ranges except for the wind density parameter (A * ), which is higher than those for bursts with wind-ISM transition, but typical for the general population of bursts. We note the importance of early-time radio observations of the afterglow (and of well-sampled light curves) for unambiguously identifying the potential contribution of the reverse shock

  20. Formation of Pyrylium from Aromatic Systems with a Helium:Oxygen Flowing Atmospheric Pressure Afterglow (FAPA) Plasma Source

    Science.gov (United States)

    Badal, Sunil P.; Ratcliff, Tyree D.; You, Yi; Breneman, Curt M.; Shelley, Jacob T.

    2017-06-01

    The effects of oxygen addition on a helium-based flowing atmospheric pressure afterglow (FAPA) ionization source are explored. Small amounts of oxygen doped into the helium discharge gas resulted in an increase in abundance of protonated water clusters by at least three times. A corresponding increase in protonated analyte signal was also observed for small polar analytes, such as methanol and acetone. Meanwhile, most other reagent ions (e.g., O2 +·, NO+, etc.) significantly decrease in abundance with even 0.1% v/v oxygen in the discharge gas. Interestingly, when analytes that contained aromatic constituents were subjected to a He:O2-FAPA, a unique (M + 3)+ ion resulted, while molecular or protonated molecular ions were rarely detected. Exact-mass measurements revealed that these (M + 3)+ ions correspond to (M - CH + O)+, with the most likely structure being pyrylium. Presence of pyrylium-based ions was further confirmed by tandem mass spectrometry of the (M + 3)+ ion compared with that of a commercially available salt. Lastly, rapid and efficient production of pyrylium in the gas phase was used to convert benzene into pyridine. Though this pyrylium-formation reaction has not been shown before, the reaction is rapid and efficient. Potential reactant species, which could lead to pyrylium formation, were determined from reagent-ion mass spectra. Thermodynamic evaluation of reaction pathways was aided by calculation of the formation enthalpy for pyrylium, which was found to be 689.8 kJ/mol. Based on these results, we propose that this reaction is initiated by ionized ozone (O3 +·), proceeds similarly to ozonolysis, and results in the neutral loss of the stable CHO2 · radical. [Figure not available: see fulltext.

  1. Hubble Space Telescope Observations of the Afterglow, Supernova and Host Galaxy Associated with the Extremely Bright GRB 130427A

    Science.gov (United States)

    Levan, A.J.; Tanvir, N. R.; Fruchter, A. S.; Hjorth, J.; Pian, E.; Mazzali, P.; Hounsell, R. A.; Perley, D. A.; Cano, Z.; Graham, J.; hide

    2014-01-01

    We present Hubble Space Telescope (HST) observations of the exceptionally bright and luminous Swift gamma-ray burst, GRB 130427A. At z=0.34 this burst affords an excellent opportunity to study the supernova and host galaxy associated with an intrinsically extremely luminous burst (E(sub iso) greater than 10(exp 54) erg): more luminous than any previous GRB with a spectroscopically associated supernova. We use the combination of the image quality, UV capability and and invariant PSF of HST to provide the best possible separation of the afterglow, host and supernova contributions to the observed light approximately 17 rest-frame days after the burst utilising a host subtraction spectrum obtained 1 year later. Advanced Camera for Surveys (ACS) grism observations show that the associated supernova, SN 2013cq, has an overall spectral shape and luminosity similar to SN 1998bw (with a photospheric velocity, vph approximately 15,000 kilometers per second). The positions of the bluer features are better matched by the higher velocity SN 2010bh (vph approximately 30,000 kilometers per second), but SN 2010bh (vph approximately 30,000 kilometers per second but this SN is significantly fainter, and fails to reproduce the overall spectral shape, perhaps indicative of velocity structure in the ejecta. We find that the burst originated approximately 4 kpc from the nucleus of a moderately star forming (1 Solar Mass yr(exp-1)), possibly interacting disc galaxy. The absolute magnitude, physical size and morphology of this galaxy, as well as the location of the GRB within it are also strikingly similar to those of GRB980425SN 1998bw. The similarity of supernovae and environment from both the most luminous and least luminous GRBs suggests broadly similar progenitor stars can create GRBs across six orders of magnitude in isotropic energy.

  2. Hubble space telescope observations of the afterglow, supernova, and host galaxy associated with the extremely bright GRB 130427A

    Energy Technology Data Exchange (ETDEWEB)

    Levan, A. J. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Tanvir, N. R.; Wiersema, K. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Fruchter, A. S.; Hounsell, R. A.; Graham, J. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hjorth, J.; Fynbo, J. P. U. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Pian, E. [INAF, Trieste Astronomical Observatory, via G.B. Tiepolo 11, I-34143 Trieste (Italy); Mazzali, P. [Astrophysics Research Institute, Liverpool John Moores University, IC2 Liverpool Science Park 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Cano, Z. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Kouveliotou, C. [Science and Technology Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Pe' er, A. [Department of Physics, University College Cork, Cork (Ireland); Misra, K., E-mail: a.j.levan@warwick.ac.uk [Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital-263 002 (India)

    2014-09-10

    We present Hubble Space Telescope (HST) observations of the exceptionally bright and luminous Swift gamma-ray burst (GRB), GRB 130427A. At z = 0.34, this burst affords an excellent opportunity to study the supernova (SN) and host galaxy associated with an intrinsically extremely luminous burst (E {sub iso} > 10{sup 54} erg): more luminous than any previous GRB with a spectroscopically associated SN. We use the combination of the image quality, UV capability, and invariant point-spread function of HST to provide the best possible separation of the afterglow, host, and SN contributions to the observed light ∼17 rest-frame days after the burst, utilizing a host subtraction spectrum obtained one year later. Advanced Camera for Surveys grism observations show that the associated SN, SN 2013cq, has an overall spectral shape and luminosity similar to SN 1998bw (with a photospheric velocity, v {sub ph} ∼ 15, 000 km s{sup –1}). The positions of the bluer features are better matched by the higher velocity SN 2010bh (v {sub ph} ∼ 30, 000 km s{sup –1}), but this SN is significantly fainter and fails to reproduce the overall spectral shape, perhaps indicative of velocity structure in the ejecta. We find that the burst originated ∼4 kpc from the nucleus of a moderately star forming (1 M {sub ☉} yr{sup –1}), possibly interacting disk galaxy. The absolute magnitude, physical size, and morphology of this galaxy, as well as the location of the GRB within it, are also strikingly similar to those of GRB 980425/SN 1998bw. The similarity of the SNe and environment from both the most luminous and least luminous GRBs suggests that broadly similar progenitor stars can create GRBs across six orders of magnitude in isotropic energy.

  3. Comparison of radiation-induced colouration images, thermoluminescence, and after-glow colour images with aluminium impurity distribution in Japanese twin quartzes

    International Nuclear Information System (INIS)

    Hashimoto, Tetsuo; Ojima, Tetsu; Takahashi, Eishi; Konishi, Masayoshi; Kanemaki, Motoko.

    1995-01-01

    After-glow colour images (AGCI) and thermoluminescence (TL) from Japanese twin quartz slices have been successfully photographed by means of a commercially available negative colour film after the irradiation of X-rays. After-glow colour images (AGCI) offered very interesting distinction of colour images; the core part showed the colour changed from sky blue with zonal orange to blue with increasing absorbed doses, whereas the outer parts maintained orange AG colour giving clear boundary. On the other hand, the radiation-induced colour (blackish or brownish) center image (CCI) appeared at the core portion, while thermoluminescence colour images (TLCI) also consisted of two portions distinguishable into stripe and zonal bluish core and faint TL emission part in outer ones. These luminescence colour images, probably reflecting the formation mechanism of Japanese twin quartzes, are evidently correlated with the concentration patterns of aluminium impurity obtained by an EPMA (electron probe microanalyzer) method. From these radiation-induced images, it was assumed that the conditions of crystal formation should be greatly different between the core and the outer parts; the outer parts were secondarily started to grow from hydrothermal solution with higher Al-concentration after the initial formation of single core. (author)

  4. First limits on the very-high energy gamma-ray afterglow emission of a fast radio burst. H.E.S.S. observations of FRB 150418

    Science.gov (United States)

    H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Coffaro, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; Dewilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'c.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Richter, S.; Rieger, F.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stycz, K.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.; Superb Collaboration; Jankowski, F.; Keane, E. F.; Petroff, E.

    2017-01-01

    Aims: Following the detection of the fast radio burst FRB150418 by the SUPERB project at the Parkes radio telescope, we aim to search for very-high energy gamma-ray afterglow emission. Methods: Follow-up observations in the very-high energy gamma-ray domain were obtained with the H.E.S.S. imaging atmospheric Cherenkov telescope system within 14.5 h of the radio burst. Results: The obtained 1.4 h of gamma-ray observations are presented and discussed. At the 99% C.L. we obtained an integral upper limit on the gamma-ray flux of Φγ(E > 350 GeV) FRB 150418. Conclusions: No hints for high-energy afterglow emission of FRB 150418 were found. Taking absorption on the extragalactic background light into account and assuming a distance of z = 0.492 based on radio and optical counterpart studies and consistent with the FRB dispersion, we constrain the gamma-ray luminosity at 1 TeV to L < 5.1 × 1047 erg/s at 99% C.L.

  5. Investigation and Applications of In-Source Oxidation in Liquid Sampling-Atmospheric Pressure Afterglow Microplasma Ionization (LS-APAG) Source.

    Science.gov (United States)

    Xie, Xiaobo; Wang, Zhenpeng; Li, Yafeng; Zhan, Lingpeng; Nie, Zongxiu

    2017-06-01

    A liquid sampling-atmospheric pressure afterglow microplasma ionization (LS-APAG) source is presented for the first time, which is embedded with both electrospray ionization (ESI) and atmospheric pressure afterglow microplasma ionization (APAG) techniques. This ion source is capable of analyzing compounds with diverse molecule weights and polarities. An unseparated mixture sample was detected as a proof-of-concept, giving complementary information (both polarities and non-polarities) with the two ionization modes. It should also be noted that molecular mass can be quickly identified by ESI with clean and simple spectra, while the structure can be directly studied using APAG with in-source oxidation. The ionization/oxidation mechanism and applications of the LS-APAG source have been further explored in the analysis of nonpolar alkanes and unsaturated fatty acids/esters. A unique [M + O - 3H] + was observed in the case of individual alkanes (C 5 -C 19 ) and complex hydrocarbons mixture under optimized conditions. Moreover, branched alkanes generated significant in-source fragments, which could be further applied to the discrimination of isomeric alkanes. The technique also facilitates facile determination of double bond positions in unsaturated fatty acids/esters due to diagnostic fragments (the acid/ester-containing aldehyde and acid oxidation products) generated by on-line ozonolysis in APAG mode. Finally, some examples of in situ APAG analysis by gas sampling and surface sampling were given as well. Graphical Abstract ᅟ.

  6. Temporal Evolution of the Gamma-ray Burst Afterglow Spectrum for an Observer: GeV–TeV Synchrotron Self-Compton Light Curve

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Takuma; Fujita, Yutaka [Department of Earth and Space Science, Osaka University, Osaka, 560-0043 (Japan); To, Sho; Asano, Katsuaki, E-mail: fukushima@vega.ess.sci.osaka-u.ac.jp, E-mail: fujita@vega.ess.sci.osaka-u.ac.jp, E-mail: tosho@icrr.u-tokyo.ac.jp, E-mail: asanok@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)

    2017-08-01

    We numerically simulate the gamma-ray burst (GRB) afterglow emission with a one-zone time-dependent code. The temporal evolutions of the decelerating shocked shell and energy distributions of electrons and photons are consistently calculated. The photon spectrum and light curves for an observer are obtained taking into account the relativistic propagation of the shocked shell and the curvature of the emission surface. We find that the onset time of the afterglow is significantly earlier than the previous analytical estimate. The analytical formulae of the shock propagation and light curve for the radiative case are also different from our results. Our results show that even if the emission mechanism is switching from synchrotron to synchrotron self-Compton, the gamma-ray light curves can be a smooth power law, which agrees with the observed light curve and the late detection of a 32 GeV photon in GRB 130427A. The uncertainty of the model parameters obtained with the analytical formula is discussed, especially in connection with the closure relation between spectral index and decay index.

  7. A Correlation Between the Intrinsic Brightness and Average Decay Rate of Gamma-Ray Burst X-Ray Afterglow Light Curves

    Science.gov (United States)

    Racusin, J. L.; Oates, S. R.; De Pasquale, M.; Kocevski, D.

    2016-01-01

    We present a correlation between the average temporal decay (alpha X,avg, greater than 200 s) and early-time luminosity (LX,200 s) of X-ray afterglows of gamma-ray bursts as observed by the Swift X-ray Telescope. Both quantities are measured relative to a rest-frame time of 200 s after the gamma-ray trigger. The luminosity â€" average decay correlation does not depend on specific temporal behavior and contains one scale-independent quantity minimizing the role of selection effects. This is a complementary correlation to that discovered by Oates et al. in the optical light curves observed by the Swift Ultraviolet Optical Telescope. The correlation indicates that, on average, more luminous X-ray afterglows decay faster than less luminous ones, indicating some relative mechanism for energy dissipation. The X-ray and optical correlations are entirely consistent once corrections are applied and contamination is removed. We explore the possible biases introduced by different light-curve morphologies and observational selection effects, and how either geometrical effects or intrinsic properties of the central engine and jet could explain the observed correlation.

  8. A COMPREHENSIVE STUDY OF GAMMA-RAY BURST OPTICAL EMISSION. II. AFTERGLOW ONSET AND LATE RE-BRIGHTENING COMPONENTS

    Energy Technology Data Exchange (ETDEWEB)

    Liang Enwei; Li Liang; Liang Yunfeng; Tang Qingwen; Chen Jiemin; Lu Ruijing; Lue Lianzhong [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Gao He; Zhang, Bing; Lue Houjun [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States); Wu Xuefeng [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Yi Shuangxi; Dai Zigao [School of Astronomy and Space Science, Nanjing University, Nanjing, Jiangsu 210093 (China); Zhang Jin; Wei Jianyan, E-mail: lew@gxu.edu.cn, E-mail: zhang@physics.unlv.edu [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2013-09-01

    We continue our systematic statistical study of various components of gamma-ray burst (GRB) optical light curves. We decompose the early onset bump and the late re-brightening bump with empirical fits and analyze their statistical properties. Among the 146 GRBs that have well-sampled optical light curves, the onset and re-brightening bumps are observed in 38 and 26 GRBs, respectively. It is found that the typical rising and decaying slopes for both the onset and re-brightening bumps are {approx}1.5 and {approx} - 1.15, respectively. No early onset bumps in the X-ray band are detected to be associated with the optical onset bumps, while an X-ray re-brightening bump is detected for half of the re-brightening optical bumps. The peak luminosity is anti-correlated with the peak time L{sub p}{proportional_to}t{sub p}{sup -1.81{+-}0.32} for the onset bumps and L{sub p}{proportional_to}t{sub p}{sup -0.83{+-}0.17} for the re-brightening bumps. Both L{sub p} and the isotropic energy release of the onset bumps are correlated with E{sub {gamma},iso}, whereas no similar correlation is found for the re-brightening bumps. These results suggest that the afterglow onset bumps are likely due to the deceleration of the GRB fireballs. Taking the onset bumps as probes for the properties of the fireballs and their ambient medium, we find that the typical power-law index of the relativistic electrons is 2.5 and the medium density profile behaves as n{proportional_to}r {sup -1} within the framework of the synchrotron external shock models. With the medium density profile obtained from our analysis, we also confirm the correlation between the initial Lorentz factor ({Gamma}{sub 0}) and E{sub iso,{gamma}} in our previous work. The jet component that produces the re-brightening bump seems to be on-axis and independent of the prompt emission jet component. Its typical kinetic energy budget would be about one order of magnitude larger than the prompt emission component, but with a lower {Gamma

  9. UVES/VLT high resolution spectroscopy of GRB 050730 afterglow: probing the features of the GRB environment

    International Nuclear Information System (INIS)

    D'Elia, V.; Fiore, F.; Piranomonte, S.; Sbordone, L.; Stella, L.; Antonelli, L.A.; Fontana, A.; Giannini, T.; Guetta, D.; Israel, G.; Testa, V.; Meurs, E.J.A.; Vergani, S.D.; Ward, P.; Chincarini, G.; Tagliaferri, G.; Campana, S.; Fugazza, D.; Molinari, E.; Moretti, A.; Chincarini, G.; Melandri, A.; Norci, L.; Vergani, S.D.; Pellizza, L.; Filliatre, P.; Perna, R.; Lazzati, D.

    2007-01-01

    Aims. The aim of this paper is to study the Gamma Ray Burst (GRB) environment through the analysis of the optical absorption features due to the gas surrounding the GRB. Methods. To this purpose we analyze high resolution spectroscopic observations (R = 20000-45000, corresponding to 14 kms -1 at 4200 Angstroms and 6.6 kms -1 at 9000 Angstroms of the optical afterglow of GRB050730, obtained with UVES-VLT ∼ 4 h after the GRB trigger. Results. The spectrum shows that the ISM of the GRB host galaxy at z = 3.967 is complex, with at least five components contributing to the main absorption system. We detect strong CII*, SiII*, OI* and FeII* fine structure absorption lines associated to the second and third component. Conclusions. For the first three components we derive information on the relative distance from the site of the GRB explosion. Component 1, which has the longest wavelength, highest positive velocity shift, does not present any fine structure nor low ionization lines; it only shows very high ionization features, such as C IV and O VI, suggesting that this component is very close to the GRB site. From the analysis of low and high ionization lines and fine structure lines, we find evidences that the distance of component 2 from the site of the GRB explosion is 10-100 times smaller than that of component 3. We evaluated the mean metallicity of the z = 3.967 system obtaining values approximate to 10 -2 of the solar metallicity or less. However, this should not be taken as representative of the circum-burst medium, since the main contribution to the hydrogen column density comes from the outer regions of the galaxy while that of the other elements presumably comes from the ISM closer to the GRB site. Furthermore, difficulties in evaluating dust depletion correction can modify significantly these values. The mean [C/Fe] ratio agrees well with that expected by single star-formation event models. Interestingly the [C/Fe] of component 2 is smaller than that of

  10. GRB afterglows: optical searches

    Czech Academy of Sciences Publication Activity Database

    Hudec, René

    2000-01-01

    Roč. 80, - (2000), s. 06/141-06/145 ISSN 0920-5632. [ Texas symposium on relativistic astrophysics and cosmology /19./. Paris, 14.12.1998-18.12.1998] R&D Projects: GA ČR GA205/99/0145 Institutional research plan: CEZ:AV0Z1003909 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.699, year: 2000

  11. On the difficulty of N({sup 4}S) atom recombination to explain the appearance of the pink afterglow in a N{sub 2} flowing discharge

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, J [Centro de Fisica dos Plasmas, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal); Sa, P A [Centro de Fisica dos Plasmas, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal); Departamento de Fisica, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal); Guerra, V [Centro de Fisica dos Plasmas, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)

    2006-01-07

    The possibility that the pink afterglow (PA) of a flowing nitrogen discharge occurs as a result of recombination of N({sup 4}S) atoms is evaluated and discussed, based on a detailed kinetic model for a microwave discharge and post-discharge. The present simulation shows that the N{sub 2}{sup +}(B{sup 2}{sigma}{sub u}{sup +},v) states responsible for the emission of the PA cannot be created via an indirect mechanism initiated with atomic recombination. Alternatively, it is indicated that the PA may have its origin in non-resonant vibration-vibration energy-exchange processes between N{sub 2}(X{sup 1}{sigma}{sub g}{sup +},v) molecules, which lead to an overpopulation of high levels of the vibrational manifold.

  12. On the difficulty of N(4S) atom recombination to explain the appearance of the pink afterglow in a N2 flowing discharge

    International Nuclear Information System (INIS)

    Loureiro, J; Sa, P A; Guerra, V

    2006-01-01

    The possibility that the pink afterglow (PA) of a flowing nitrogen discharge occurs as a result of recombination of N( 4 S) atoms is evaluated and discussed, based on a detailed kinetic model for a microwave discharge and post-discharge. The present simulation shows that the N 2 + (B 2 Σ u + ,v) states responsible for the emission of the PA cannot be created via an indirect mechanism initiated with atomic recombination. Alternatively, it is indicated that the PA may have its origin in non-resonant vibration-vibration energy-exchange processes between N 2 (X 1 Σ g + ,v) molecules, which lead to an overpopulation of high levels of the vibrational manifold

  13. Challenging the Forward Shock Model with the 80 Ms Follow up of the X-ray Afterglow of Gamma-Ray Burst 130427A

    Directory of Open Access Journals (Sweden)

    Massimiliano De Pasquale

    2017-01-01

    Full Text Available GRB 130427A was the most luminous gamma-ray burst detected in the last 30 years. With an isotropic energy output of 8.5 × 10 53 erg and redshift of 0.34, it combined very high energetics with a relative proximity to Earth in an unprecedented way. Sensitive X-ray observatories such as XMM-Newton and Chandra have detected the afterglow of this event for a record-breaking baseline longer than 80 million seconds. The light curve displays a simple power-law over more than three decades in time. In this presentation, we explore the consequences of this result for a few models put forward so far to interpret GRB 130427A, and more in general the implication of this outcome in the context of the standard forward shock model.

  14. Optical light curve of GRB 121011A: a textbook for the onset of GRB afterglow in a mixture of ISM and wind-type medium

    International Nuclear Information System (INIS)

    Xin, Li-Ping; Wei, Jian-Yan; Qiu, Yu-Lei; Deng, Jin-Song; Wang, Jing; Han, Xu-Hui

    2016-01-01

    We report the optical observations of GRB 121011A by the 0.8m TNT facility at Xinglong observatory, China. The light curve of the optical afterglow shows a smooth and featureless bump during the epoch of ∼130 s and ∼5000 s with a rising index of 1.57 ± 0.28 before the break time of 539 ± 44 s, and a decaying index of about 1.29 ± 0.07 up to the end of our observations. Moreover, the X-ray light curve decays in a single power-law with a slope of about 1.51 ± 0.03 observed by XRT onboard Swift from 100 s to about 10 000 s after the burst trigger. The featureless optical light curve could be understood as an onset process under the external-shock model. The typical frequency has been below or near the optical one before the deceleration time, and the cooling frequency is located between the optical and X-ray wavelengths. The external medium density has a transition from a mixed stage of ISM and wind-type medium before the peak time to the ISM at the later phase. The joint-analysis of X-ray and optical light curves shows that the emissions from both frequencies are consistent with the prediction of the standard afterglow model without any energy injections, indicating that the central engine has stopped its activity and does not restart anymore after the prompt phase. (paper)

  15. Drop-on-demand sample introduction system coupled with the flowing atmospheric-pressure afterglow for direct molecular analysis of complex liquid microvolume samples.

    Science.gov (United States)

    Schaper, J Niklas; Pfeuffer, Kevin P; Shelley, Jacob T; Bings, Nicolas H; Hieftje, Gary M

    2012-11-06

    One of the fastest developing fields in analytical spectrochemistry in recent years is ambient desorption/ionization mass spectrometry (ADI-MS). This burgeoning interest has been due to the demonstrated advantages of the method: simple mass spectra, little or no sample preparation, and applicability to samples in the solid, liquid, or gaseous state. One such ADI-MS source, the flowing atmospheric-pressure afterglow (FAPA), is capable of direct analysis of solids just by aiming the source at the solid surface and sampling the produced ions into a mass spectrometer. However, direct introduction of significant volumes of liquid samples into this source has not been possible, as solvent loads can quench the afterglow and, thus, the formation of reagent ions. As a result, the analysis of liquid samples is preferably carried out by analyzing dried residues or by desorbing small amounts of liquid samples directly from the liquid surface. In the former case, reproducibility of sample introduction is crucial if quantitative results are desired. In the present study, introduction of liquid samples as very small droplets helps overcome the issues of sample positioning and reduced levels of solvent intake. A recently developed "drop-on-demand" (DOD) aerosol generator is capable of reproducibly producing very small volumes of liquid (∼17 pL). In this paper, the coupling of FAPA-MS and DOD is reported and applications are suggested. Analytes representing different classes of substances were tested and limits of detections were determined. Matrix tolerance was investigated for drugs of abuse and their metabolites by analyzing raw urine samples and quantification without the use of internal standards. Limits of detection below 2 μg/mL, without sample pretreatment, were obtained.

  16. Packaging materials for plasma sterilization with the flowing afterglow of an N{sub 2}-O{sub 2} discharge: damage assessment and inactivation efficiency of enclosed bacterial spores

    Energy Technology Data Exchange (ETDEWEB)

    Levif, P; Moisan, M; Soum-Glaude, A [Groupe de Physique des Plasmas, Universite de Montreal, CP 6128, Succursale Centre-Ville, Montreal H3C 3J7, Quebec (Canada); Seguin, J; Barbeau, J, E-mail: michel.moisan@umontreal.ca [Faculte de Medecine Dentaire, Laboratoire de Controle des Infections, Universite de Montreal, CP 6128, Montreal H3C 3J7, Quebec (Canada)

    2011-10-12

    In conventional sterilization methods (steam, ozone, gaseous chemicals), after their proper cleaning, medical devices are wrapped/enclosed in adequate packaging materials, then closed/sealed before initiating the sterilization process: these packaging materials thus need to be porous. Gaseous plasma sterilization being still under development, evaluation and comparison of packaging materials have not yet been reported in the literature. To this end, we have subjected various porous packagings used with conventional sterilization systems to the N{sub 2}-O{sub 2} flowing afterglow and also a non-porous one to evaluate and compare their characteristics towards the inactivation of B. atrophaeus endospores deposited on a Petri dish and enclosed in such packagings. Because the sterilization process with the N{sub 2}-O{sub 2} discharge afterglow is conducted under reduced-pressure conditions, non-porous pouches can be sealed only after returning to atmospheric pressure. All the tests were therefore conducted with one end of the packaging freely opened, post-sealing being required. The features of these packaging materials, namely mass loss, resistance, toxicity to human cells as well as some characteristics specific to the plasma method used such as ultraviolet transparency, were examined before and after exposure to the flowing afterglow. All of our results show that the non-porous packaging considered is much more suitable than the conventionally used porous ones as far as ensuring an efficient and low-damage sterilization process with an N{sub 2}-O{sub 2} plasma-afterglow is concerned.

  17. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    Science.gov (United States)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  18. VLT/X-Shooter spectroscopy of the afterglow of the Swift GRB 130606A. Chemical abundances and reionisation at z ~ 6

    Science.gov (United States)

    Hartoog, O. E.; Malesani, D.; Fynbo, J. P. U.; Goto, T.; Krühler, T.; Vreeswijk, P. M.; De Cia, A.; Xu, D.; Møller, P.; Covino, S.; D'Elia, V.; Flores, H.; Goldoni, P.; Hjorth, J.; Jakobsson, P.; Krogager, J.-K.; Kaper, L.; Ledoux, C.; Levan, A. J.; Milvang-Jensen, B.; Sollerman, J.; Sparre, M.; Tagliaferri, G.; Tanvir, N. R.; de Ugarte Postigo, A.; Vergani, S. D.; Wiersema, K.; Datson, J.; Salinas, R.; Mikkelsen, K.; Aghanim, N.

    2015-08-01

    Context. The reionisation of the Universe is a process that is thought to have ended around z ~ 6, as inferred from spectroscopy of distant bright background sources, such as quasars (QSO) and gamma-ray burst (GRB) afterglows. Furthermore, spectroscopy of a GRB afterglow provides insight in its host galaxy, which is often too dim and distant to study otherwise. Aims: For the Swift GRB 130606A at z = 5.913 we have obtained a high S/N spectrum covering the full optical and near-IR wavelength region at intermediate spectral resolution with VLT/X-Shooter. We aim to measure the degree of ionisation of the intergalactic medium (IGM) between z = 5.02-5.84 and to study the chemical abundance pattern and dust content of its host galaxy. Methods: We estimated the UV continuum of the GRB afterglow using a power-law extrapolation, then measured the flux decrement due to absorption at Lyα,β, and γ wavelength regions. Furthermore, we fitted the shape of the red damping wing of Lyα. The hydrogen and metal absorption lines formed in the host galaxy were fitted with Voigt profiles to obtain column densities. We investigated whether ionisation corrections needed to be applied. Results: Our measurements of the Lyα-forest optical depth are consistent with previous measurements of QSOs, but have a much smaller uncertainty. The analysis of the red damping wing yields a neutral fraction xH i 5.6. GRBs are useful probes of the ionisation state of the IGM in the early Universe, but because of internal scatter we need a larger statistical sample to draw robust conclusions. The high [Si/Fe] in the host can be due to dust depletion, α-element enhancement, or a combination of both. The very high value of [ Al/Fe ] = 2.40 ± 0.78 might be due to a proton capture process and is probably connected to the stellar population history. We estimate the host metallicity to be -1.7 Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the

  19. SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

    International Nuclear Information System (INIS)

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-01-01

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρ ext ∝r –k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ 0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ –1 0 . For larger k values, however, the lateral expansion is faster at early times (when Γ > θ –1 0 ) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θ obs ≤ θ 0 ) than by the slope of the external density profile (for 0 ≤ k ≤ 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet

  20. Simulations of Gamma-Ray Burst Jets in a Stratified External Medium: Dynamics, Afterglow Light Curves, Jet Breaks, and Radio Calorimetry

    Science.gov (United States)

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-05-01

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρextvpropr -k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ-1 0. For larger k values, however, the lateral expansion is faster at early times (when Γ > θ-1 0) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θobs <= θ0) than by the slope of the external density profile (for 0 <= k <= 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet decelerates more

  1. The 2175 Å Extinction Feature in the Optical Afterglow Spectrum of GRB 180325A at z = 2.25

    Science.gov (United States)

    Zafar, T.; Heintz, K. E.; Fynbo, J. P. U.; Malesani, D.; Bolmer, J.; Ledoux, C.; Arabsalmani, M.; Kaper, L.; Campana, S.; Starling, R. L. C.; Selsing, J.; Kann, D. A.; de Ugarte Postigo, A.; Schweyer, T.; Christensen, L.; Møller, P.; Japelj, J.; Perley, D.; Tanvir, N. R.; D’Avanzo, P.; Hartmann, D. H.; Hjorth, J.; Covino, S.; Sbarufatti, B.; Jakobsson, P.; Izzo, L.; Salvaterra, R.; D’Elia, V.; Xu, D.

    2018-06-01

    The ultraviolet (UV) extinction feature at 2175 Å is ubiquitously observed in the Galaxy but is rarely detected at high redshifts. Here we report the spectroscopic detection of the 2175 Å bump on the sightline to the γ-ray burst (GRB) afterglow GRB 180325A at z = 2.2486, the only unambiguous detection over the past 10 years of GRB follow-up, at four different epochs with the Nordic Optical Telescope (NOT) and the Very Large Telescope (VLT)/X-shooter. Additional photometric observations of the afterglow are obtained with the Gamma-Ray burst Optical and Near-Infrared Detector (GROND). We construct the near-infrared to X-ray spectral energy distributions (SEDs) at four spectroscopic epochs. The SEDs are well described by a single power law and an extinction law with R V ≈ 4.4, A V ≈ 1.5, and the 2175 Å extinction feature. The bump strength and extinction curve are shallower than the average Galactic extinction curve. We determine a metallicity of [Zn/H] > ‑0.98 from the VLT/X-shooter spectrum. We detect strong neutral carbon associated with the GRB with equivalent width of W r(λ 1656) = 0.85 ± 0.05. We also detect optical emission lines from the host galaxy. Based on the Hα emission-line flux, the derived dust-corrected star formation rate is ∼46 ± 4 M ⊙ yr‑1 and the predicted stellar mass is log M */M ⊙ ∼ 9.3 ± 0.4, suggesting that the host galaxy is among the main-sequence star-forming galaxies. Based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO program 0100.D‑0649(A).

  2. SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

    Energy Technology Data Exchange (ETDEWEB)

    De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)

    2012-05-20

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with {rho}{sub ext}{proportional_to}r{sup -k} for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle {theta}{sub 0} = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor {Gamma} drops below {theta}{sup -1}{sub 0}. For larger k values, however, the lateral expansion is faster at early times (when {Gamma} > {theta}{sup -1}{sub 0}) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for {theta}{sub obs} {<=} {theta}{sub 0}) than by the slope of the external density profile (for 0 {<=} k {<=} 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results

  3. Study of an atmospheric pressure flowing afterglow in N2/NO mixture and its application to the measurement of N2(A) concentration

    International Nuclear Information System (INIS)

    Pointu, A M; Mintusov, E; Fromy, P

    2010-01-01

    The transportation of species in a high velocity (∼10 3 cm s -1 ) flowing corona afterglow of molecular nitrogen at atmospheric pressure with added NO as impurity ( -5 ) is studied. The variation of species densities along 50 cm downstream of the discharge in an 8 mm inner diameter tube is modelled and compared with emission spectroscopy measurements. It is shown that, according to a quite simple O and NO kinetic mechanism for such a gas composition in the post discharge, N 2 (A) concentration can be obtained from the emissions of the NO γ band at 247.9 nm and the NO β band at 320.7 nm using a low resolution spectrometer (1 nm). The validity of both the measurement technique and of the assumed creation and loss mechanisms of N 2 (A) are demonstrated. An empirical relationship using the ratios of two line intensities has been plotted for several hundred points. The N 2 (A) concentration thus obtained, around 10 11 cm -3 , depending on the experimental conditions, is consistent with the results of direct measurements using the N 2 Vegard-Kaplan system at 260.4 nm.

  4. EFFECT OF ALKALINE IONS ON THE PHASE EVOLUTION, PHOTOLUMINESCENCE, AND AFTERGLOW PROPERTIES OF SrAl2O4: Eu2+, Dy3+ PHOSPHOR

    Directory of Open Access Journals (Sweden)

    HYUNHO SHIN

    2012-12-01

    Full Text Available A series of SrAl2O4: Eu2+, Dy3+ long-afterglow (LAG phosphors with varying concentration of Li+, Na+ and K+, has been synthesized. The increased concentration of the three types of alkaline ions does not decrease the quantity of the total luminescent phases (SrAl2O4 plus Sr4Al14O25, but a different set of secondary phases has been evoluted for the K+-added series due to the failure of the incorporation of relatively large K+ (1.38 Å to the Sr2+ (1.18 Å site in the hosts, unlike the cases of smaller Li+ (0.76 Å and Na+ (1.02 Å ions. PL excitation, PL emission, and LAG luminescence, are decreased by all investigated alkaline ions, which would be due to the diminished incorporation of Eu2+ and Dy3+ activators into the luminescent hosts by the alkaline ions. For the cases of the Li+ and Na+-added series, the incorporated Li+ or Na+ to the luminescent hosts would also limit the activation of Eu2+ and charge trapping/detrapping of Dy3+ to yield the diminished PL properties and LAG luminescence. The type of defect complex formed by the addition of Li+ and Na+ ions has been deduced and compared with that formed when no alkaline ion is added.

  5. [Effect of different excitation monitoring wavelengths on emission spectrum of red long afterglow phosphor Sr3Al2O6 : Eu2+, Dy3+].

    Science.gov (United States)

    Cui, Cai-e; Li, Jian; Huang, Ping; Liang, Li-ping; Wu, Yin-lan

    2012-01-01

    The Eu2+ and Dy3+ ion co-doped Sr3Al2O6 phosphor powders with long afterglow were prepared with high temperature solid-state reaction. The phase and the spectra properties of the material were characterized by X-ray diffraction (XRD) and fluorescence spectrophotometer. It was found that the sample is composed of pure Sr3Al2O6 phase. Furthermore, the emission peak of 537 nm under 360 nm excitation and that of 590 nm excited by 468 nm-light were obtained, respectively, and it is more interesting that the emission peaks were at 537 and 590 nm under 394 nm excitation. The effects of different excitation wavelengths on the emission spectrum were explained reasonably by the effect of nephelauxetic effect and crystal field. It revealed that the two types of luminescence with different color were caused by the differences of the center of gravity of the 5d excited state energy level and the split range of 5d energy level.

  6. Photoluminescence, afterglow and thermoluminescence in SrAl2O4:Eu2+,Dy3+ irradiated with blue and UV light

    International Nuclear Information System (INIS)

    Chernov, V.; Piters, T.M.; Melendrez, R.; Yen, W.M.; Cruz-Zaragoza, E.; Barboza-Flores, M.

    2007-01-01

    The luminescence in SrAl 2 O 4 :Eu 2+ ,Dy 3+ under continuous excitation is quite different from the 'standard' intra-ion photoluminescence (PL) and gradually grows during hundreds of seconds before reaching the saturation (photo-charging effect). In this work, we report the behavior of photo-charging effect under the blue and UV light irradiation at temperatures between 20 and 370 K, as well as afterglow (AG) and thermoluminescence (TL) observed after the irradiation termination. At 20 K the photo-charging effect is absent. With increasing temperature the photo-charging effect appears as a result of PL decreasing due to competitive trapping process with activation energy of 0.17 eV. The AG decay curves are described well by the Becquerel's law with the exponent close to 1. The AG decay time is about 10-50 s and practically does not depend on temperature. The TL glow curve exhibits at least seven partially overlapped peaks with maxima at 50, 65, 80, 155, 200, 250 and 290 K. The emission spectra of Eu 2+ consist of two bands at 450 and 520 nm. Both the bands are the same for the PL, AG and TL spectra, but their ratio depends on temperature and the luminescence type

  7. Gamma-Ray Burst Afterglows as Probes of Environment and Blast Wave Physics. II. The Distribution of rho and Structure of the Circumburst Medium

    Science.gov (United States)

    Starling, R. L. C.; vanderHorst, A. J.; Rol, E.; Wijers, R. A. M. J.; Kouveliotou, C.; Wiersema, K.; Curran, P. A.; Weltervrede, P.

    2008-01-01

    We constrain blast wave parameters and the circumburst media ofa subsample of 10 BeppoSAX gamma-ray bursts (GRBs). For this sample we derive the values of the injected electron energy distribution index, p, and the density structure index of the circumburst medium, k, from simultaneous spectral fits to their X-ray, optical, and NIR afterglow data. The spectral fits have been done in count space and include the effects ofmetallicity, and are compared with the previously reported optical and X-ray temporal behavior. Using the blast wave model and some assumptions which include on-axis viewing and standard jet structure, constant blast wave energy, and no evolution of the microphysical parameters, we find a mean value ofp for the sample as a whole of 9.... oa -0.003.0" 2 a_ statistical analysis of the distribution demonstrates that the p-values in this sample are inconsistent with a single universal value forp at the 3 _ level or greater, which has significant implications for particle acceleration models. This approach provides us with a measured distribution ofcircumburst density structures rather than considering only the cases of k ----0 (homogeneous) and k - 2 (windlike). We find five GRBs for which k can be well constrained, and in four of these cases the circumburst medium is clearly windlike. The fifth source has a value of 0 medium.

  8. Gamma-Ray Burst Afterglows as Probes of Environment and Blastwave Physics II: The Distribution of p and Structure of the Circumburst Medium

    Science.gov (United States)

    Starling, R. L. C.; vanderHorst, A. J.; Rol, E.; Wijers, R. A. M. J.; Kouveliotou, C.; Wiersema, K.; Curran, P. A.; Weltevrede, P.

    2007-01-01

    We constrain blastwave parameters and the circumburst media of a subsample of BeppoSAX Gamma-Ray Bursts. For this sample we derive the values of the injected electron energy distribution index, p, and the density structure index of the circumburst medium, k, from simultaneous spectral fits to their X-ray, optical and nIR afterglow data. The spectral fits have been done in count space and include the effects of metallicity, and are compared with the previously reported optical and X-ray temporal behaviour. Assuming the fireball model, we can find a mean value of p for the sample as a whole of 2.035. A statistical analysis Of the distribution demonstrates that the p values in this sample are inconsistent with a single universal value for p at the 3sigma level or greater. This approach provides us with a measured distribution of circumburst density structures rather than considering only the cases of k = 0 (homogeneous) and k = 2 (wind-like). We find five GRBs for which k can be well constrained, and in four of these cases the circumburst medium is clearly wind-like. The fifth source has a value of 0 less than or equal to k less than or equal to 1, consistent with a homogeneous circumburst medium.

  9. Tuning the luminescence color and enhancement of afterglow properties of Sr(4−x−y)CaxBayAl14O25:Eu2+,Dy3+ phosphor by adjusting the composition

    International Nuclear Information System (INIS)

    Luitel, Hom Nath; Watari, Takanori; Chand, Rumi; Torikai, Toshio; Yada, Mitsunori; Mizukami, Hiroshi

    2013-01-01

    Graphical abstract: Excitation and fluorescence emission spectra of three extreme compositions of Ca, Sr and Ba in Sr 4 Al 14 O 25 phosphor (viz. 4CaO·7Al 2 O 3 , 4SrO·7Al 2 O 3 and 4BaO·7Al 2 O 3 ) doped with 4 at% Eu 2+ and 8 at% Dy 3+ (inset shows the digital micrograph of corresponding phosphors). -- Highlights: • Bright phosphor, Sr (4−x−y) Ca x Ba y Al 14 O 25 :Eu 2+ ,Dy 3+ , was synthesized by adjusting the composition. • The solid solubility of Ca and Ba in the Sr 4 Al 14 O 25 host was determined to be 20 and 10 mol%, respectively. • Substituting part of Sr by Ca, the emission color can be well tuned from blue to green. • A white afterglow was observed when 3.2 mol of Sr was substituted by Ca. • The afterglow luminescence was enhanced by 1.5 times by 0.2 mol Ca substitution. -- Abstract: Color point tuning is an important challenge for improving the practical applications of various displays, especially there are very limited white color single hosts that emits in the white spectrum. In this paper, the possibility of color tuning by substituting part of host lattice cation (Sr 2+ ions) by Ca 2+ or Ba 2+ ions in an efficient strontium aluminate phosphor, Sr 4 Al 14 O 25 :Eu 2+ ,Dy 3+ , is reported and found to be very promising for displays. A detail study by replacing part of Sr 2+ with Ca 2+ or Ba 2+ has been investigated. X-ray diffraction study showed that crystal structure of Sr 4 Al 14 O 25 is preserved up to 20 mol of Ca 2+ ion exchange while it is limited to 10 mol of Ba 2+ ions exchange. Substantial shift in the emission band and color were observed by substitution of Sr 2+ by Ca 2+ or Ba 2+ ions. A bluish-white emission and afterglow was observed at higher Ca 2+ ions substitution. Further, partial Ca 2+ substitutions (up to 0.8 mol) resulted in enhanced afterglow of Sr 4 Al 14 O 25 :Eu 2+ ,Dy 3+ phosphor. However, Ba 2+ substitution decreased the fluorescence as well afterglow of the Sr 4 Al 14 O 25 :Eu 2+ ,Dy 3+ phosphor

  10. COASTING EXTERNAL SHOCK IN WIND MEDIUM: AN ORIGIN FOR THE X-RAY PLATEAU DECAY COMPONENT IN SWIFT GAMMA-RAY BURST AFTERGLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Shen Rongfeng; Matzner, Christopher D., E-mail: rfshen@astro.utoronto.ca, E-mail: matzner@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Ontario M5S 3H4 (Canada)

    2012-01-01

    The plateaus observed in about one half of the early X-ray afterglows are the most puzzling feature in gamma-ray bursts (GRBs) detected by Swift. By analyzing the temporal and spectral indices of a large X-ray plateau sample, we find that 55% can be explained by external, forward shock synchrotron emission produced by a relativistic ejecta coasting in a {rho}{proportional_to}r{sup -2}, wind-like medium; no energy injection into the shock is needed. After the ejecta collects enough medium and transitions to the adiabatic, decelerating blast wave phase, it produces the post-plateau decay. For those bursts consistent with this model, we find an upper limit for the initial Lorentz factor of the ejecta, {Gamma}{sub 0} {<=} 46({epsilon}{sub e}/0.1){sup -0.24}({epsilon}{sub B}/0.01){sup 0.17}; the isotropic equivalent total ejecta energy is E{sub iso} {approx} 10{sup 53}({epsilon}{sub e}/0.1){sup -1.3}({epsilon}{sub B}/0.01){sup -0.09}(t{sub b} /10{sup 4} s) erg, where {epsilon}{sub e} and {epsilon}{sub B} are the fractions of the total energy at the shock downstream that are carried by electrons and the magnetic field, respectively, and t{sub b} is the end of the plateau. Our finding supports Wolf-Rayet stars as the progenitor stars of some GRBs. It raises intriguing questions about the origin of an intermediate-{Gamma}{sub 0} ejecta, which we speculate is connected to the GRB jet emergence from its host star. For the remaining 45% of the sample, the post-plateau decline is too rapid to be explained in the coasting-in-wind model, and energy injection appears to be required.

  11. Electronic-state distribution of Ar* produced from Ar+(2P3/2)/2e- collisional radiative recombination in an argon flowing afterglow

    International Nuclear Information System (INIS)

    Tsuji, Masaharu; Matsuzaki, Toshinori; Tsuji, Takeshi

    2002-01-01

    The Ar + /2e - collisional radiative recombination has been studied by observing UV and visible emissions of Ar* in an Ar flowing afterglow. In order to clarify recombination mechanism, the Ar + ( 2 P 3/2 ) spin-orbit component was selected by using a filter gas of the Ar + ( 2 P 1/2 ) component. Spectral analysis indicated that 34 Ar*(4p, 4d, 5p, 5d, 6s, 6p, 6d, 4p ' , 4d ' , 5p ' , 5d ' , 6s ' ) states in the 13.08-15.33 eV range are produced. The electronic-state distribution decreased with an increase in the excitation energy of Ar*, which was expressed by a Boltzmann electronic temperature of 0.54 eV. The formation ratios of the 4p: 4d + 5p + 5d + 6s + 6p + 6d: 4p ' : 4d ' + 5p ' + 5d ' + 6s ' states were 43%, 2.8%, 54%, and 0.31%, respectively. The high formation ratio of the 4p ' state having an Ar + ( 2 P 1/2 ) ion core in the Ar + ( 2 P 3/2 )/2e - recombination indicated that such a two-electron process as an electron transfer to an inner 3p orbital followed by excitation of a 3p electron to an outer 4p orbital occurs significantly. The higher formation ratios of 4d + 5p + 5d + 6s + 6p + 6d than those of 4d ' + 5p ' + 5d ' + 6s ' led us to conclude the formation of these upper states dominantly proceeds through one electron transfer to an outer nl orbital of Ar + ( 2 P 3/2 )

  12. Determination, through titration with NO, of the concentration of oxygen atoms in the flowing afterglow of Ar-O2 and N2-O2 plasmas used for sterilization purposes

    Science.gov (United States)

    Ricard, A.; Moisan, M.; Moreau, S.

    2001-04-01

    Les méthodes existantes de titrage de N et O d'une post-décharge au moyen de l'intensité d'émission de la molécule NO excitée ne permettant pas d'aller au-delà de x = 5% dans un mélange xO2-(100%-x)N2, nous présentons une démarche valable pour x≤20%. Cette technique est fondée sur la mesure de l'intensité d'émission de NO2(A), en fonction du débit de NO introduit, en relation avec une dérivation analytique des équations des concentrations [N] et [O]. La concentration d'oxygène atomique obtenue par cette méthode est validée de façon indépendante à partir de la mesure du rapport des intensités d'émission de NO(B) et de N2(B, 11) (celle-ci détectable pour x≤8%). Enfin, la méthode proposée est mise en oeuvre pour apprécier l'influence de la valeur de la concentration d'oxygène atomique sur le temps de stérilisation dans une post-décharge en flux à partir d'un plasma de N2-O2. \\engabstract Existing titration methods of N and O in an afterglow based on the emission intensity of the excited NO molecule cannot be used at x values exceeding 5% in the xO2-(100%-x)N2 mixture. Our technique extends the x range to 20%. It utilizes the emission intensity measurement of NO2(A), as a function of the introduced NO flow, in relation with analytically derived equations for the O and N concentrations. The atomic oxygen concentration obtained in this way is validated independently through measurements of the emission intensity ratio of NO(B) and N2(B, 11) (detectable for x≤8%). Finally, the proposed method is used to assess the influence of the oxygen atom concentration on the sterilization time in the flowing afterglow of an N2-O2 plasma.

  13. Tunable Yellow-Red Photoluminescence and Persistent Afterglow in Phosphors Ca4LaO(BO3)3:Eu3+ and Ca4EuO(BO3)3.

    Science.gov (United States)

    Chen, Zhen; Pan, Yuexiao; Xi, Luqing; Pang, Ran; Huang, Shaoming; Liu, Guokui

    2016-11-07

    In most Eu 3+ activated phosphors, only red luminescence from the 5 D 0 is obtainable, and efficiency is limited by concentration quenching. Herein we report a new phosphor of Ca 4 LaO(BO 3 ) 3 :Eu 3+ (CLBO:Eu) with advanced photoluminescence properties. The yellow luminescence emitted from the 5 D 1,2 states is not thermally quenched at room temperature. The relative intensities of the yellow and red emission bands depend strongly on the Eu 3+ doping concentration. More importantly, concentration quenching of Eu 3+ photoluminescence is absent in this phosphor, and the stoichiometric compound of Ca 4 EuO(BO 3 ) 3 emits stronger luminescence than the Eu 3+ doped compounds of CLBO:Eu; it is three times stronger than that of a commercial red phosphor of Y 2 O 3 :Eu 3+ . Another beneficial phenomenon is that ligand-to-metal charge transfer (CT) transitions occur in the long UV region with the lowest charge transfer band (CTB) stretched down to about 3.67 eV (∼330 nm). The CT transitions significantly enhance Eu 3+ excitation, and thus result in stronger photoluminescence and promote trapping of excitons for persistent afterglow emission. Along with structure characterization, optical spectra and luminescence dynamics measured under various conditions as a function of Eu 3+ doping, temperature, and excitation wavelength are analyzed for a fundamental understanding of electronic interactions and for potential applications.

  14. Burst Alert Robotic Telescope and Optical Afterglows

    Czech Academy of Sciences Publication Activity Database

    Nekola, Martin; Hudec, René; Jelínek, M.; Kubánek, P.; Polášek, Cyril; Štrobl, Jan

    2009-01-01

    Roč. 18, 3/4 (2009), s. 374-378 ISSN 1392-0049. [INTEGRAL/BART workshop 2009. Karlovy Vary, 26.03.2009-29.03.2009] R&D Projects: GA ČR GA205/08/1207 Grant - others:ESA(XE) ESA-PECS project No. 98023; Spanish Ministry of Education and Science(ES) AP2003-1407 Institutional research plan: CEZ:AV0Z10030501 Keywords : gamma rays bursts, * observations * robotic telescopes Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.032, year: 2009

  15. PROBING EXTRAGALACTIC DUST THROUGH NEARBY GAMMA-RAY BURST AFTERGLOWS

    International Nuclear Information System (INIS)

    Liang, S. L.; Li Aigen

    2010-01-01

    The quantities and wavelength dependencies of the dust extinction along the lines of sight toward 33 nearby gamma-ray bursts (GRBs) with redshifts z V derived from the Drude approach is generally larger by a factor of ∼2-5 than that inferred by assuming a SMC-type template extinction law. Consistent with previous studies, the extinction-to-gas ratio is mostly smaller than that of the MW, and does not seem to correlate with the shape of the extinction curve. It is shown that the standard silicate-graphite interstellar grain model closely reproduces the extinction curves of all 33 GRBs host galaxies. For these 33 bursts at z < 2, we find no evidence for the evolution of the dust extinction, dust sizes, and relative abundances of silicate to graphite on redshifts.

  16. TGF afterglows: A new radiation mechanism from thunderstorms

    NARCIS (Netherlands)

    C. Rutjes (Casper); G. Diniz (Gabriel); I.S. Ferreira; U. M. Ebert (Ute)

    2017-01-01

    textabstractThunderstorms are known to create terrestrial gamma ray flashes (TGFs) which are microsecond-long bursts created by runaway of thermal electrons from propagating lightning leaders, as well as gamma ray glows that possibly are created by relativistic runaway electron avalanches (RREA)

  17. TGF afterglows : a new radiation mechanism from thunderstorms

    NARCIS (Netherlands)

    Rutjes, C.; Diniz, G.; Ferreira, I.S.; Ebert, U.

    2017-01-01

    Thunderstorms are known to create terrestrial gamma ray flashes (TGFs) which are microsecond-long bursts created by runaway of thermal electrons from propagating lightning leaders, as well as gamma ray glows that possibly are created by relativistic runaway electron avalanches (RREA) that can last

  18. NASA Space Observatories Glimpse Faint Afterglow of Nearby Stellar Explosion

    Science.gov (United States)

    2005-10-01

    Intricate wisps of glowing gas float amid a myriad of stars in this image created by combining data from NASA's Hubble Space Telescope and Chandra X-ray Observatory. The gas is a supernova remnant, cataloged as N132D, ejected from the explosion of a massive star that occurred some 3,000 years ago. This titanic explosion took place in the Large Magellanic Cloud, a nearby neighbor galaxy of our own Milky Way. The complex structure of N132D is due to the expanding supersonic shock wave from the explosion impacting the interstellar gas of the LMC. Deep within the remnant, the Hubble visible light image reveals a crescent-shaped cloud of pink emission from hydrogen gas, and soft purple wisps that correspond to regions of glowing oxygen emission. A dense background of colorful stars in the LMC is also shown in the Hubble image. The large horseshoe-shaped gas cloud on the left-hand side of the remnant is glowing in X-rays, as imaged by Chandra. In order to emit X-rays, the gas must have been heated to a temperature of about 18 million degrees Fahrenheit (10 million degrees Celsius). A supernova-generated shock wave traveling at a velocity of more than four million miles per hour (2,000 kilometers per second) is continuing to propagate through the low-density medium today. The shock front where the material from the supernova collides with ambient interstellar material in the LMC is responsible for these high temperatures. Chandra image of N132D Chandra image of N132D, 2002 It is estimated that the star that exploded as a supernova to produce the N132D remnant was 10 to 15 times more massive than our own Sun. As fast-moving ejecta from the explosion slam into the cool, dense interstellar clouds in the LMC, complex shock fronts are created. A supernova remnant like N132D provides a rare opportunity for direct observation of stellar material, because it is made of gas that was recently hidden deep inside a star. Thus it provides information on stellar evolution and the creation of chemical elements such as oxygen through nuclear reactions in their cores. Such observations also help reveal how the interstellar medium (the gas that occupies the vast spaces between the stars) is enriched with chemical elements because of supernova explosions. Later on, these elements are incorporated into new generations of stars and their accompanying planets. Visible only from Earth's southern hemisphere, the LMC is an irregular galaxy lying about 160,000 light-years from the Milky Way. The supernova remnant appears to be about 3,000 years old, but since its light took 160,000 years to reach us, the explosion actually occurred some 163,000 years ago. This composite image of N132D was created by the Hubble Heritage team from visible-light data taken in January 2004 with Hubble's Advanced Camera for Surveys, and X-ray images obtained in July 2000 by Chandra's Advanced CCD Imaging Spectrometer. This marks the first Hubble Heritage image that combines pictures taken by two separate space observatories. The Hubble data include color filters that sample starlight in the blue, green, and red portions of the spectrum, as well as the pink emission from glowing hydrogen gas. The Chandra data are assigned blue in the color composite, in accordance with the much higher energy of the X-rays, emitted from extremely hot gas. This gas does not emit a significant amount of optical light, and was only detected by Chandra. Image Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: J.C. Green (Univ. of Colorado) and the Cosmic Origins Spectrograph (COS) GTO team; NASA/CXO/SAO Electronic image files, video, illustrations and additional information are available at: http://hubblesite.org/news/2005/30 http://heritage.stsci.edu/2005/30 The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

  19. Jetted GRBs, afterglows and SGRs from quark stars birth

    CERN Document Server

    Dar, Arnon

    1999-01-01

    Recent studies suggest that when cold nuclear matter is compressed to high nuclear densities, diquarks with spin zero and antisymmetric color wave function Bose condensate into a superfluid/superconducting state that is several times as dense. Various astrophysical phenomena may be explained by gravitational collapse of neutron stars (NSs) to (di)quark stars (QSs) as a result of a first order phase transition in NSs within $\\sim 10^{4}$ years after their birth in supernova explosions, when they cooled and spun down sufficiently (by magnetic braking ?). The gravitational energy release drives an explosion which may eject both highly relativistic narrowly collimated jets and a mildly relativistic ``spherical'' shell. The slow contraction/cooling of the remnant QSs can power soft gamma ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs), without invoking a huge magnetic energy storage. The jets can produce the observed gamma ray bursts (GRBs) in distant galaxies when they happen to point in our direction and...

  20. Complicated variations in the early optical afterglow of GRB 090726

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Polášek, Cyril; Jelínek, M.; Hudec, René; Štrobl, Jan

    2010-01-01

    Roč. 510, February (2010), A49/1-A49/5 ISSN 0004-6361 R&D Projects: GA ČR GA205/08/1207 Grant - others:GA ČR(CZ) GA102/09/0997; ESA(XE) ESA-PECS project No. 98058 Institutional research plan: CEZ:AV0Z10030501 Keywords : gamma-ray burst * radiation mechanisms * plasmas Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.410, year: 2010

  1. New relativistic particle-in-cell simulation studies of prompt and early afterglows from GRBs

    International Nuclear Information System (INIS)

    Ken-Ichi Nishikawa

    2008-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electro-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the collisionless relativistic shock particle acceleration is due to plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electrons' transverse deflection behind the jet head. The '' jitter '' radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants. (author)

  2. Electric Discharge and Afterglow Kinetics for Laser Mixtures with Carbon Monoxide, Oxygen and Iodine

    National Research Council Canada - National Science Library

    Ionin, Andrey

    2006-01-01

    ...: Previous research carried out under the ISTC partner contracts has demonstrated that an electric discharge could be a powerful means for producing highly excited CO molecules needed for overtone CO...

  3. The extraordinarily bright optical afterglow of GRB 991208 and its host galaxy

    DEFF Research Database (Denmark)

    Castro-Tirado, A.J.; Sokolov, V.V.; Gorosabel, J.

    2001-01-01

    that GRB 991208 is at 3.7 Gpc (for H-0 = 60 km s(-1) Mpc(-1), Omega (0) = 1 and Lambda (0) = 0), implying an isotropic energy release of 1.15 10(53) erg which may. be relaxed by beaming by a factor >10(2). Precise astrometry indicates that the GRB coincides within 0.2" with the host galaxy, thus supporting...... a massive star origin. The absolute magnitude of the galaxy is M-B = -18.2, well below the knee of the galaxy luminosity function and we derive a star-forming rate of (11.5 +/- 7.1) M-circle dot yr(-1), which is much larger than the present-day rate in our Galaxy. The quasi simultaneous broad...

  4. Le X-ray telescopes: innovative experiment to monitor X-ray afterglows of GRBs

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Pína, L.; Inneman, A.; Gorenstein, P.; Melich, Z.

    2000-01-01

    Roč. 80, - (2000), s. 06/161-06/163 ISSN 0920-5632. [ Texas symposium on relativistic astrophysics and cosmology /19./. Paris, 14.12.1998-18.12.1998] Institutional research plan: CEZ:AV0Z1003909 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.699, year: 2000

  5. The rapidly flaring afterglow of the very bright and energetic GRB 070125

    NARCIS (Netherlands)

    Updike, A.C.; Haislip, J.B.; Nysewander, M.C.; Fruchter, A.S.; Kann, D.A.; Klose, S.; Milne, P.A.; Williams, G.G.; Zheng, W.; Hergenrother, C.W.; Prochaska, J.X.; Halpern, J.P.; Mirabal, N.; Thorstensen, J.R.; van der Horst, A.J.; Starling, R.L.C.; Racusin, J.L.; Burrows, D.N.; Kuin, N.P.M.; Roming, P.W.A.; Bellm, E.; Hurley, K.; Li, W.; Filippenko, A.V.; Blake, C.; Starr, D.; Falco, E.E.; Brown, W.R.; Dai, X.; Deng, J.; Xin, L.; Qiu, Y.; Wei, J.; Urata, Y.; Nanni, D.; Maiorano, E.; Palazzi, E.; Greco, G.; Bartolini, C.; Guarnieri, A.; Piccioni, A.; Pizzichini, G.; Terra, F.; Misra, K.; Bhatt, B.C.; Anupama, G.C.; Fan, X.; Jiang, L.; Wijers, R.A.M.J.; Reichart, D.E.; Eid, H.A.; Bryngelson, G.; Puls, J.; Goldthwaite, R.C.; Hartmann, D.H.

    2008-01-01

    We report on multiwavelength observations, ranging from X-ray to radio wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic observations reveal the presence of absorption lines due to O I, Si II, and C IV, implying a likely redshift of z = 1.547. The well-sampled light curves,

  6. Recombination of H+3 ions in the afterglow of a He-Ar-H2 plasma

    International Nuclear Information System (INIS)

    Glosik, J; Korolov, I; Plasil, R; Novotny, O; Kotrik, T; Hlavenka, P; Varju, J; Mikhailov, I A; Kokoouline, V; Greene, Chris H

    2008-01-01

    Recombination of H + 3 with electrons is studied in a low-temperature plasma containing He, H 2 and Ar at different He and H 2 densities. The effective plasma recombination rate is driven by binary, H + 3 + e - , and ternary, H + 3 + e - + He, processes with the rate coefficients 7.5 x 10 -8 cm 3 s -1 and 2.8 x 10 -25 cm 6 s -1 respectively at 260 K. We suggest that the ternary recombination involves formation of neutral highly excited Rydberg H 3 followed by an l-changing collision with He. The difference between recombination of para- and ortho-H + 3 is discussed. (fast track communication)

  7. Beam On Target (BOT) Produces Gamma Ray Burst (GRB) Fireballs and Afterglows

    Science.gov (United States)

    Greyber, H. D.

    1997-12-01

    Unlike the myriads of ad hoc models that have been offered to explain GRB, the BOT process is simply the very common process used worldwide in accelerator laboratories to produce gamma rays. The Strong Magnetic Field (SMF) model postulates an extremely intense, highly relativistic current ring formed during the original gravitational collapse of a distant galaxy when the plasma cloud was permeated by a primordial magnetic field. GRB occur when solid matter (asteroid, white dwarf, neutron star, planet) falls rapidly through the Storage Ring beam producing a very strongly collimated electromagnetic shower, and a huge amount of matter from the target, in the form of a giant, hot, expanding plasma cloud, or ``Fireball,'' is blown off. BOT satisfies all the ``severe constraints imposed on the source of this burst --'' concluded by the CGRO team (Sommer et al, Astrophys. J. 422 L63 (1994)) for the huge intense burst GRB930131, whereas neutron star merger models are ``difficult to reconcile.'' BOT expects the lowest energy gamma photons to arrive very slightly later than higher energy photons due to the time for the shower to penetrate the target. The millisecond spikes in bursts are due to the slender filaments of current that make up the Storage Ring beam. Delayed photons can be explained by a broken target ``rock.'' See H. Greyber in the book ``Compton Gamma Ray Observatory,'' AIP Conf. Proc. 280, 569 (1993).

  8. Ratiometric Afterglow Nanothermometer for Simultaneous in Situ Bioimaging and Local Tissue Temperature Sensing

    NARCIS (Netherlands)

    Yang, J.; Liu, Y.; Zhao, Y.; Gong, Z.; Zhang, M.; Yan, D.; Zhu, H.; Liu, C.; Xu, C.; Zhang, H.

    2017-01-01

    Simultaneous in situ bioimage tracing and temperature sensing have been two of the foci of modern biomedicine that have given birth to designing novel luminescent nanothermometers with dual functions. To minimize the disadvantages of existing approaches, like the surface effect of nanoparticles,

  9. Constraints on the optical afterglow emission of the short/hard burst GRB 010119

    DEFF Research Database (Denmark)

    Gorosabel, J.; Andersen, M.I.; Hjorth, J.

    2002-01-01

    We report optical observations of the short/hard burst GRB 010119 error box, one of the smallest error boxes reported to date for short/hard GRBs. Limits of R >22.3 and I >21.2 are imposed by observations carried out 20.31 and 20.58 hours after the gamma-ray event, respectively. They represent th...

  10. Surface chemistry of water-dispersed detonation nanodiamonds modified by atmospheric DC plasma afterglow

    Czech Academy of Sciences Publication Activity Database

    Štenclová, Pavla; Celedova, V.; Artemenko, Anna; Jirásek, Vít; Jíra, Jaroslav; Rezek, B.; Kromka, Alexander

    2017-01-01

    Roč. 7, č. 62 (2017), s. 38973-38980 ISSN 2046-2069 R&D Projects: GA ČR GA15-01687S Institutional support: RVO:68378271 Keywords : diamond nanoparticles * explosive detonation * barrier discharge * absorption * oxidation Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.108, year: 2016

  11. Colors and absolute magnitudes of the optical afterglows of X-ray flashes

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, René; Pizzichini, G.

    2006-01-01

    Roč. 121, č. 12 (2006), s. 1579-1581 ISSN 1594-9982. [Swift and GRBs: Unveiling the Relativistic Universe. Venezia, 05.06.2006-09.06.2006] R&D Projects: GA AV ČR IAA3003206 Grant - others:EU(XE) ESA-PECS project No. 98023; EU(XE) ESA PRODEX INTEGRAL 90108 Institutional research plan: CEZ:AV0Z10030501 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : gamma-ray bursts * supernovae * radiation mechanisms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.351, year: 2006

  12. Colors and luminosities of the optical afterglows of the gamma-ray bursts

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, René; Pizzichini, G.; Masetti, N.

    2001-01-01

    Roč. 377, č. 2 (2001), s. 450-461 ISSN 0004-6361 R&D Projects: GA AV ČR KSK1048102; GA MŠk ME 137; GA MŠk ME 002; GA ČR GA205/99/0145 Institutional research plan: CEZ:AV0Z1003909 Keywords : gamma rays * bursts * radiation mechanisms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.790, year: 2000

  13. Colors and absolute magnitudes of the optical afterglow of GRB060218

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Pizzichini, G.; Hudec, René

    2006-01-01

    Roč. 121, č. 12 (2006), s. 1585-1587 ISSN 1594-9982. [Swift and GRBs: Unveiling the Relativistic Universe. Venezia, 05.06.2006-09.06.2006] R&D Projects: GA AV ČR IAA3003206 Grant - others:EU(XE) ESA-PECS project No. 98023; EU(XE) ESA PRODEX INTEGRAL 90108 Institutional research plan: CEZ:AV0Z10030501 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : gamma-ray bursts * radiation mechanisms * supernovae Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.351, year: 2006

  14. What the colors of optical afterglows tell us about their spektra

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, René; Pizzichini, G.

    2006-01-01

    Roč. 121, č. 12 (2006), s. 1583-1584 ISSN 1594-9982. [Swift and GRBs: Unveiling the Relativistic Universe. Venezia, 05.06.2006-09.06.2006] R&D Projects: GA AV ČR IAA3003206 Grant - others:EU(XE) ESA-PECS project No. 98023; EU(XE) ESA PRODEX INTEGRAL 90108 Institutional research plan: CEZ:AV0Z10030501 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : gamma-ray bursts * radiation mechanisms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.351, year: 2006

  15. VLT/X-shooter spectroscopy of the GRB 120327A afterglow

    DEFF Research Database (Denmark)

    D'Elia, V.; Fynbo, Johan Peter Uldall; Goldoni, P.

    2014-01-01

    we used to derive information on the distance between the host absorbing gas and the site of the GRB explosion. The variability of the FeI\\lambda2396 excited line between the two epochs proves that these features are excited by the GRB UV flux. Moreover, the distance of component I is found to be d......I=200+100-60 pc, while component II is located closer to the GRB, at dII=100+40-30 pc. These values are among the lowest found in GRBs. Component III does not show excited transitions, so it should be located farther away from the GRB. The presence of H2 molecules is firmly established, with a molecular...

  16. Observation of the prompt and early afterglow of GRB 050904 by TAROT

    International Nuclear Information System (INIS)

    Boeer, M.; Damerdji, Y.; Atteia, J. L.; Stratta, G.; Gendre, B.; Klotz, A.

    2006-01-01

    We present the recent observation of the very high redshift burst source GRB 050904 made by the TAROT robotized telescope. We have compared our data with the SWIFT XRT light curve to analyze the broad ban spectrum. We show that the luminosity and the behavior of this event is comparable with that of GRB 990123, suggesting the existence of very bright events. They can be detected at very high redshifts, even with small or moderate aperture telescopes, and they may constitute a powerful means for the exploration of the young universe. An update of the last TAROT observations performed as a response from SWIFT alerts is made

  17. Infrared Chemiluminescence Studies of Ion-Molecule Reactions in a Flowing Afterglow.

    Science.gov (United States)

    1982-01-01

    reaction rate constants and branching ratios have been addressed in drift tubes and flow drift systems, and the translational energy distribution of atomic...composed of about 40 thin cylindrical sections of flow tube , separated by mylar spacers and connected by precision resistors. In the region of LIF... tube radius (Albritton, 1967). For proper operation of a drift tube , ionic species of only one polarity can be present. Efficient separation of

  18. GRB 110715A: the peculiar multiwavelength evolution of the first afterglow detected by ALMA

    Czech Academy of Sciences Publication Activity Database

    Sánchez-Ramírez, R.; Hancock, P. J.; Johannesson, G.; Murphy, T.; de Ugarte Postigo, A.; Gorosabel, J.; Kann, D.A.; Kruehler, T.; Oates, S.R.; Japelj, J.; Thöne, C.C.; Lundgren, A.; Perley, D.A.; Malesani, D.; de Gregorio Monsalvo, I.; Castro-Tirado, A.J.; D'Elia, V.; Fynbo, J. P. U.; Garcia-Appadoo, D.; Goldoni, P.; Greiner, J.; Hu, Y.D.; Jelínek, Martin; Jeong, S.; Kamble, S.; Klose, S.; Kuindersma, S.; Llorente, A.; Martin, S.; Guelbenzu, A. N.; Rossi, A.; Schady, P.; Sparrer, G.; Sudilovsky, V.; Tello, J. C.; Updike, A.; Wiersema, K.; Zhang, B.B.

    2017-01-01

    Roč. 464, č. 4 (2017), s. 4624-4640 ISSN 0035-8711 Institutional support: RVO:67985815 Keywords : gamma-ray burst * vlt/x-shooter spectroscopy * host galaxy Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 4.961, year: 2016

  19. Recombination of H{sup +}{sub 3} ions in the afterglow of a He-Ar-H{sub 2} plasma

    Energy Technology Data Exchange (ETDEWEB)

    Glosik, J; Korolov, I; Plasil, R; Novotny, O; Kotrik, T; Hlavenka, P; Varju, J [Mathematics and Physics Faculty, Charles University in Prague, Prague 8 (Czech Republic); Mikhailov, I A; Kokoouline, V [Department of Physics, University of Central Florida, Orlando, FL 32816 (United States); Greene, Chris H [Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440 (United States)], E-mail: Juraj.Glosik@mff.cuni.cz

    2008-10-14

    Recombination of H{sup +}{sub 3} with electrons is studied in a low-temperature plasma containing He, H{sub 2} and Ar at different He and H{sub 2} densities. The effective plasma recombination rate is driven by binary, H{sup +}{sub 3} + e{sup -}, and ternary, H{sup +}{sub 3} + e{sup -}+ He, processes with the rate coefficients 7.5 x 10{sup -8} cm{sup 3} s{sup -1} and 2.8 x 10{sup -25} cm{sup 6} s{sup -1} respectively at 260 K. We suggest that the ternary recombination involves formation of neutral highly excited Rydberg H{sub 3} followed by an l-changing collision with He. The difference between recombination of para- and ortho-H{sup +}{sub 3} is discussed. (fast track communication)

  20. FAST TRACK COMMUNICATION: Recombination of H+3 ions in the afterglow of a He Ar H2 plasma

    Science.gov (United States)

    Glosik, J.; Korolov, I.; Plasil, R.; Novotny, O.; Kotrik, T.; Hlavenka, P.; Varju, J.; Mikhailov, I. A.; Kokoouline, V.; Greene, Chris H.

    2008-10-01

    Recombination of H+3 with electrons is studied in a low-temperature plasma containing He, H2 and Ar at different He and H2 densities. The effective plasma recombination rate is driven by binary, H+3 + e-, and ternary, H+3 + e-+ He, processes with the rate coefficients 7.5 × 10-8 cm3 s-1 and 2.8 × 10-25 cm6 s-1 respectively at 260 K. We suggest that the ternary recombination involves formation of neutral highly excited Rydberg H3 followed by an l-changing collision with He. The difference between recombination of para- and ortho-H+3 is discussed.

  1. Afterglow Studies of H3+(v=0) Recombination using Time Resolved cw.Diode Laser Cavity Ring-Down Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macko, P.; Bánó, G.; Hlavenka, P.; Plašil, R.; Poterya, V.; Pysanenko, A.; Votava, Ondřej; Johnsen, R.; Glosík, J.

    2004-01-01

    Roč. 233, 1/3 (2004), s. 299-304 ISSN 1387-3806 R&D Projects: GA ČR GA205/02/0610; GA ČR GA202/02/0948 Institutional research plan: CEZ:AV0Z4040901 Keywords : recombination * H-3(+) ions * cavity ring-down Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.235, year: 2004

  2. Perspectives of observing the color indices of optical afterglows of gamma-ray bursts with ESA Gaia

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, R.; Pizzichini, G.

    2017-01-01

    Roč. 44, č. 1 (2017), s. 129-146 ISSN 0922-6435 Grant - others:GA ČR(CZ) GA13-33324S Institutional support: RVO:67985815 Keywords : radiation mechanisms * astronomical instrumentation * methods and techniques Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.313, year: 2016

  3. Numerical study of active particles creation and evolution in a nitrogen point-to-plane afterglow discharge at low pressure

    International Nuclear Information System (INIS)

    Potamianou, S; Spyrou, N; Held, B; Loiseau, J-F

    2006-01-01

    The last part of a numerical study of low-pressure nitrogen cold plasma created by a pulsed discharge in a point-to-plane geometry at 4 Torr is presented. The present work deals with the discharge and plasma behaviour during the falling part of a rectangular shaped applied voltage pulse and completes our investigation of the discharge under the stress of this voltage shape. The relative model is based on fluid description of the cold plasma, on Poisson's equation for the electric field and on balance equations for the excited population taking into account only the most important generation and decay mechanisms of the radiative B 3 Π g , C 3 Π u and the metastables A 3 Σ μ + states of nitrogen, according to the conclusions of our recent work (Potamianou et al 2003 Eur. Phys. J. Appl. Phys. 22 179-88). Results for space and time evolution of the charged particles densities, electric field, potential and electron current density are reported. According to these results, a non-neutral channel is formed that evolves slowly and ends in the formation of a double layer. Excited particle distributions are presented and the influence of the electron current density discussed. It seems that, in this kind of discharge, creation of active particles is not only due to electron current density but also physicochemical mechanisms. The obtained results will help to determine optimal conditions for polymer surface treatment

  4. Gamma-ray burst afterglows as probes of environment and blast wave physics. II. The distribution of p and structure of the circumburst medium

    NARCIS (Netherlands)

    Starling, R.L.C.; van der Horst, A.J.; Rol, E.; Wijers, R.A.M.J.; Kouveliotou, C.; Wiersema, K.; Curran, P.A.; Weltevrede, P.

    2008-01-01

    We constrain blast wave parameters and the circumburst media of a subsample of 10 BeppoSAX gamma-ray bursts (GRBs). For this sample we derive the values of the injected electron energy distribution index, p, and the density structure index of the circumburst medium, k, from simultaneous spectral

  5. The afterglow of the short/intermediate-duration gamma-ray burst GRB 000301C: A jet at z=2.04

    DEFF Research Database (Denmark)

    Jensen, B.L.; Fynbo, J.U.; Gorosabel, J.

    2001-01-01

    We present Ulysses and NEAR data from the detection of the short or intermediate duration (2 s) gamma-ray burst GRB 000301C (2000 March 1.41 UT). The gamma-ray burst (GRB) was localised by the Inter Planetary Network (IPN) and RXTE to an area of similar to 50 arcmin(2). A fading optical counterpa...

  6. Assessing the Psychedelic "After-Glow" in Ayahuasca Users: Post-Acute Neurometabolic and Functional Connectivity Changes Are Associated with Enhanced Mindfulness Capacities.

    Science.gov (United States)

    Sampedro, Frederic; de la Fuente Revenga, Mario; Valle, Marta; Roberto, Natalia; Domínguez-Clavé, Elisabet; Elices, Matilde; Luna, Luís Eduardo; Crippa, José Alexandre S; Hallak, Jaime E C; de Araujo, Draulio B; Friedlander, Pablo; Barker, Steven A; Álvarez, Enrique; Soler, Joaquim; Pascual, Juan C; Feilding, Amanda; Riba, Jordi

    2017-09-01

    Ayahuasca is a plant tea containing the psychedelic 5-HT2A agonist N,N-dimethyltryptamine and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network, purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here, we investigated in an open-label uncontrolled study in 16 healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications and their association with mindfulness measures. Using 1H-magnetic resonance spectroscopy and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior and anterior cingulate cortex after a single ayahuasca dose. Magnetic resonance spectroscopy showed post-acute reductions in glutamate+glutamine, creatine, and N-acetylaspartate+N-acetylaspartylglutamate in the posterior cingulate cortex. Connectivity was increased between the posterior cingulate cortex and the anterior cingulate cortex, and between the anterior cingulate cortex and limbic structures in the right medial temporal lobe. Glutamate+glutamine reductions correlated with increases in the "nonjudging" subscale of the Five Facets Mindfulness Questionnaire. Increased anterior cingulate cortex-medial temporal lobe connectivity correlated with increased scores on the self-compassion questionnaire. Post-acute neural changes predicted sustained elevations in nonjudging 2 months later. These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the posterior cingulate cortex, a key region within the default mode network, and increased connectivity between the anterior cingulate cortex and medial temporal lobe structures involved in emotion and memory potentially underlie the post-acute psychological effects of ayahuasca. © The Author 2017. Published by Oxford University Press on behalf of CINP.

  7. Effect of nitrogen plasma afterglow on the surface charge effect resulted during XPS surface analysis of amorphous carbon nitride thin films

    Science.gov (United States)

    Kayed, Kamal

    2018-06-01

    The aim of this paper is to investigate the relationship between the micro structure and the surface charge effect resulted during XPS surface analysis of amorphous carbon nitride thin films prepared by laser ablation method. The study results show that the charge effect coefficient (E) is not just a correction factor. We found that the changes in this coefficient value due to incorporation of nitrogen atoms into the carbon network are related to the spatial configurations of the sp2 bonded carbon atoms, order degree and sp2 clusters size. In addition, results show that the curve E vs. C(sp3)-N is a characteristic curve of the micro structure. This means that using this curve makes it easy to sorting the samples according to the micro structure (hexagonal rings or chains).

  8. Erratum: "Low-Resolution Spectroscopy of Gamma-Ray Burst Optical Afterglows: Biases in the Swift Sample and Characterization of the Absorbers" (2009, ApJS, 185, 526)

    Science.gov (United States)

    Fynbo, J. P. U.; Jakobsson, P.; Prochaska, J. X.; Malesani, D.; Ledoux, C.; de Ugarte Postigo, A.; Nardini, M.; Vreeswijk, P. M.; Wiersema, K.; Hjorth, J.; Sollerman, J.; Chen, H.-W.; Thöne, C. C.; Björnsson, G.; Bloom, J. S.; Castro-Tirado, A.; Christensen, L.; De Cia, A.; Fruchter, A. S.; Gorosabel, J. U.; Graham, J. F.; Jaunsen, A. O.; Jensen, B. L.; Kann, D. A.; Kouveliotou, C.; Levan, A.; Maund, J.; Masetti, N.; Milvang-Jensen, B.; Palazzi, E.; Perley, D. A.; Pian, E.; Rol, E.; Schady, P.; Starling, R.; Tanvir, N.; Watson, D. J.; Xu, D.; Augusteijn, T.; Grundahl, F.; Telting, J.; Quirion, P.-O.

    2010-02-01

    In this paper, Figure 14 is incomplete due to an error during production. We here provide the missing sub-figures. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under programs 275.D-5022, 075.D-0270, 077.D-0661, 077.D-0805, 078.D-0416, 079.D-0429, 080.D-0526, 081.A-0135, 281.D-5002, and 081.A-0856. Also based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Some of the data obtained herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  9. The Prompt-afterglow Connection in Gamma-ray Bursts: a Comprehensive Statistical Analysis of Swift X-ray Light-curves

    Science.gov (United States)

    Margutti, R.; Zaninoni, E.; Bernardini, M. G.; Chincarini, G.; Pasotti, F.; Guidorzi, C.; Angelini, Lorella; Burrows, D. N.; Capalbi, M.; Evans, P. A.; hide

    2012-01-01

    We present a comprehensive statistical analysis of Swift X-ray light-curves of Gamma- Ray Bursts (GRBs) collecting data from more than 650 GRBs discovered by Swift and other facilities. The unprecedented sample size allows us to constrain the rest-frame X-ray properties of GRBs from a statistical perspective, with particular reference to intrinsic time scales and the energetics of the different light-curve phases in a common rest-frame 0.3-30 keV energy band. Temporal variability episodes are also studied and their properties constrained. Two fundamental questions drive this effort: i) Does the X-ray emission retain any kind of "memory" of the prompt ?-ray phase? ii) Where is the dividing line between long and short GRB X-ray properties? We show that short GRBs decay faster, are less luminous and less energetic than long GRBs in the X-rays, but are interestingly characterized by similar intrinsic absorption. We furthermore reveal the existence of a number of statistically significant relations that link the X-ray to prompt ?-ray parameters in long GRBs; short GRBs are outliers of the majority of these 2-parameter relations. However and more importantly, we report on the existence of a universal 3-parameter scaling that links the X-ray and the ?-ray energy to the prompt spectral peak energy of both long and short GRBs: E(sub X,iso)? E(sup 1.00+/-0.06)(sub ?,iso) /E(sup 0.60+/-0.10)(sub pk).

  10. Dispersal kinetics of deuterated water in the lungs and airways following mouth inhalation: real-time breath analysis by flowing afterglow mass spectrometry (FA-MS)

    Czech Academy of Sciences Publication Activity Database

    Tan, B. K.; Smith, D.; Španěl, Patrik; Davies, S. J.

    2010-01-01

    Roč. 4, č. 1 (2010), 017109 ISSN 1752-7155 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * breath analysis * pulmonary-edema Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.828, year: 2010

  11. Low-resolution VLT spectroscopy of GRBs 991216, 011211 and 021211

    NARCIS (Netherlands)

    Vreeswijk, P.M.; Smette, A.; Fruchter, A.S.; Palazzi, E.; Rol, E.; Wijers, R.A.M.J.; Kouveliotou, C.; Kaper, L.; Pian, E.; Masetti, N.; Frontera, F.; Hjorth, J.; Gorosabel, J.; Piro, L.; Fynbo, J.P.U.; Jakobsson, P.; Watson, D.; O'Brien, P.T.; Ledoux, C.

    2006-01-01

    We present low-resolution VLT spectroscopy of the afterglow of the gamma-ray bursts (GRBs) 991216, 011211 and 021211. Our spectrum of GRB 991216 is the only optical spectrum for this afterglow. It shows two probable absorption systems at z=0.80 and z=1.02, where the highest redshift most likely

  12. Multiwavelength analysis of the intriguing GRB 061126: The reverse shock scenario and magnetization

    NARCIS (Netherlands)

    Gomboc, A.; Kobayashi, S.; Guidorzi, C.; Melandri, A.; Mangano, V.; Sbarufatti, B.; Mundell, C.G.; Schady, P.; Smith, R.J.; Updike, A.C.; Kann, D.A.; Misra, K.; Rol, E.; Pozanenko, A.; Castro-Tirado, A.J.; Anupama, G.C.; Bersier, D.; Bode, M.F.; Carter, D.; Curran, P.; Fruchter, A.; Graham, J.; Hartmann, D.H.; Ibrahimov, M.; Levan, A.; Monfardini, A.; Mottram, C.J.; O'Brien, P.T.; Prema, P.; Sahu, D.K.; Steele, I.A.; Tanvir, N.R.; Wiersema, K.

    2008-01-01

    We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT, UVOT data and multicolor optical imaging from 10 ground-based telescopes. GRB 061126 was a long burst (T90 = 191 s) with four overlapping peaks in its γ-ray light curve. The X-ray afterglow,

  13. IDENTIFYING THE LOCATION IN THE HOST GALAXY OF THE SHORT GRB 111117A WITH THE CHANDRA SUBARCSECOND POSITION

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, T.; Troja, E. [Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Aoki, K. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Guiriec, S.; Barthelmy, S. D. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Im, M.; Jeon, Y. [Center for the Exploration of the Origin of the Universe (CEOU), Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of); Leloudas, G.; Malesani, D.; De Ugarte Postigo, A.; Andersen, M. I. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Melandri, A.; D' Avanzo, P. [INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy); Urata, Y. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Xu, D. [Department of Particle Physics and Astronomy, The Weizmann Institute of Science, Rehovot 76100 (Israel); Gorosabel, J.; Sanchez-Ramirez, R. [Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Bai, J. [Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan Province, 650011 (China); Briggs, M. S. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Foley, S. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); and others

    2013-03-20

    We present our successful Chandra program designed to identify, with subarcsecond accuracy, the X-ray afterglow of the short GRB 111117A, which was discovered by Swift and Fermi. Thanks to our rapid target of opportunity request, Chandra clearly detected the X-ray afterglow, though no optical afterglow was found in deep optical observations. The host galaxy was clearly detected in the optical and near-infrared band, with the best photometric redshift of z=1.31{sub -0.23}{sup +0.46} (90% confidence), making it one of the highest known short gamma-ray burst (GRB) redshifts. Furthermore, we see an offset of 1.0 {+-} 0.2 arcsec, which corresponds to 8.4 {+-} 1.7 kpc, between the host and the afterglow position. We discuss the importance of using Chandra for obtaining subarcsecond X-ray localizations of short GRB afterglows to study GRB environments.

  14. Relaxation rates studies in an argon cylindrical plasma

    International Nuclear Information System (INIS)

    Hernandez, M.A.; Dengra, A.; Colomer, V.

    1986-01-01

    The single Langmuir probe method has been used to determine the relaxation rates of the electron density and temperature in an argon afterglow dc cylindrical plasma. The ion-electron recombination was found to be the fundamental mechanism of density decay during the early afterglow while the ambipolar diffusion controlles the density decay for later afterglow. Electron temperature cooling curves have been interpreted via electron-neutral collisons. Measurements of the electron-ion recombination and the ambipolar diffusion coefficients have been made, as well as of the electron-neutral collision frequency and the momentum transfer cross sections. Good agreement is obtained with previously published data. (author)

  15. VizieR Online Data Catalog: GRB 160509A VLA monitoring campain results (Laskar+, 2016)

    Science.gov (United States)

    Laskar, T.; Alexander, K. D.; Berger, E.; Fong, W.-F.; Margutti, R.; Shivvers, I.; Williams, P. K. G.; Kopac, D.; Kobayashi, S.; Mundell, C.; Gomboc, A.; Zheng, W.; Menten, K. M.; Graham, M. L.; Filippenko, A. V.

    2017-04-01

    GRB 160509A was discovered by the Fermi LAT on 2016 May 09 at 08:59:04.36 UTC (Longo+ 2016GCN..19403...1L). We observed the afterglow with the VLA starting at 0.36 days. We tracked the flux density of the afterglow over multiple epochs spanning 1.2-33.5GHz, using 3C48, 3C286, and 3C147 as flux and bandpass calibrators, and J2005+7752 as the gain calibrator. Our VLA observations spanning 0.36-20 days after the burst clearly reveal the presence of multiple spectral components in the radio afterglow. (1 data file).

  16. Gamma-ray burst theory after Swift.

    Science.gov (United States)

    Piran, Tsvi; Fan, Yi-Zhong

    2007-05-15

    Afterglow observations in the pre-Swift era confirmed to a large extend the relativistic blast wave model for gamma-ray bursts (GRBs). Together with the observations of properties of host galaxies and the association with (type Ic) SNe, this has led to the generally accepted collapsar origin of long GRBs. However, most of the afterglow data was collected hours after the burst. The X-ray telescope and the UV/optical telescope onboard Swift are able to slew to the direction of a burst in real time and record the early broadband afterglow light curves. These observations, and in particular the X-ray observations, resulted in many surprises. While we have anticipated a smooth transition from the prompt emission to the afterglow, many observed that early light curves are drastically different. We review here how these observations are changing our understanding of GRBs.

  17. Multi-band Observations of Gamma Ray Bursts

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    A statistical analysis to estimate the probable redshifts of host galaxies using the luminosity function ... shown that fading Optical Transient (OT) is observable over a couple of months from ... 99% confidence level) come from afterglow analysis.

  18. Injection of deuterated water into the pulmonary/alveolar circulation; measurement of HDO in exhaled breath and implications to breath analysis

    Czech Academy of Sciences Publication Activity Database

    Tan, B. K.; Davies, S. J.; Španěl, Patrik; Smith, D.

    2012-01-01

    Roč. 6, č. 3 (2012), 036005 ISSN 1752-7155 Institutional support: RVO:61388955 Keywords : total body water * afterglow mass spectrometry * deuterium abundance Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.571, year: 2012

  19. Method and system for improving the definition of a scintillation detector

    International Nuclear Information System (INIS)

    Wilson, J.B.

    1977-01-01

    The definition of a tomographic readout image is highly sharpened and improved by minimizing or eliminating the effects of persisting images in the electronic scintillating circuit resulting from phosphorescent afterglow, by utilizing a special filter network in the detecting circuit

  20. Low lag luminescent phosphors

    International Nuclear Information System (INIS)

    1976-01-01

    The addition of potassium or rubidium salts to europium-activated fluorohalide phosphors produces X-ray screens with low lag, even at very low europium concentrations. The chemical preparation and afterglow test results are described

  1. Centre de Physique atomique de Toulouse

    International Nuclear Information System (INIS)

    Blanc, Daniel.

    The following topics are covered by the researches in progress: atomic collisions, afterglow in gases, dc discharges in gases at intermediate and high pressures, electric arcs, dielectrics, radiation transport in matter, and aerosol physics and exchanges in the atmosphere [fr

  2. GRB 170817A as a jet counterpart to gravitational wave trigger GW 170817

    Science.gov (United States)

    Lamb, Gavin P.; Kobayashi, Shiho

    2018-05-01

    Fermi/GBM (Gamma-ray Burst Monitor) and INTEGRAL (the International Gamma-ray Astrophysics Laboratory) reported the detection of the γ-ray counterpart, GRB 170817A, to the LIGO (Light Interferometer Gravitational-wave Observatory)/Virgo gravitational wave detected binary neutron star merger, GW 170817. GRB 170817A is likely to have an internal jet or another origin such as cocoon emission, shock-breakout, or a flare from a viscous disc. In this paper we assume that the γ-ray emission is caused by energy dissipation within a relativistic jet and we model the afterglow synchrotron emission from a reverse- and forward-shock in the outflow. We show the afterglow for a low-luminosity γ-ray burst (GRB) jet with a high Lorentz-factor (Γ); a low-Γ and low-kinetic energy jet; a low-Γ, high kinetic energy jet; structured jets viewed at an inclination within the jet-half-opening angle; and an off-axis `typical' GRB jet. All jet models will produce observable afterglows on various timescales. The late-time afterglow from 10-110 days can be fit by a Gaussian structured jet viewed at a moderate inclination, however the GRB is not directly reproduced by this model. These jet afterglow models can be used for future GW detected NS merger counterparts with a jet afterglow origin.

  3. Defect Engineering by Codoping in KCaI3 :Eu2 + Single-Crystalline Scintillators

    Science.gov (United States)

    Wu, Yuntao; Li, Qi; Jones, Steven; Dun, Chaochao; Hu, Sheng; Zhuravleva, Mariya; Lindsey, Adam C.; Stand, Luis; Loyd, Matthew; Koschan, Merry; Auxier, John; Hall, Howard L.; Melcher, Charles L.

    2017-09-01

    Eu2 + -doped alkali or alkali earth iodide scintillators with energy resolutions ≤3 % at 662 keV promise the excellent discrimination ability for radioactive isotopes required for homeland-security and nuclear-nonproliferation applications. To extend their applications to x-ray imaging, such as computed tomography scans, the intense afterglow which delays the response time of such materials is an obstacle that needs to be overcome. However, a clear understanding of the origin of the afterglow and feasible solutions is still lacking. In this work, we present a combined experimental and theoretical investigation of the physical insights of codoping-based defect engineering which can reduce the afterglow effectively in KCaI3:Eu2 + single-crystal scintillators. We illustrate that Sc3 + codoping greatly suppresses the afterglow, whereas Y3 + , Gd3 + , or La3 + codoping enhances the afterglow. Meanwhile, a light yield of 57 000 photons / MeV and an energy resolution of 3.4% at 662 keV can be maintained with the appropriate concentration of Sc3 + codoping, which makes the material promising for medical-imaging applications. Through our thermoluminescence techniques and density-functional-theory calculations, we are able to identify the defect structures and understand the mechanism by which codoping affects the scintillation performance of KCaI3:Eu2 + crystals. The proposed defect-engineering strategy is further validated by achieving afterglow suppression in Mg2 + codoped KCaI3:Eu2 + single crystals.

  4. GRB 130603B: No Compelling Evidence for Neutron Star Merger

    Directory of Open Access Journals (Sweden)

    Shlomo Dado

    2015-01-01

    Full Text Available The near infrared (NIR flare/rebrightening in the afterglow of the short hard gamma ray burst (SHB 130603B measured with the Hubble Space Telescope (HST and an alleged late-time X-ray excess were interpreted as possible evidence of a neutron star merger origin of SHBs. However, the X-ray afterglow that was measured with the Swift XRT and Newton XMM has the canonical behaviour of a synchrotron afterglow produced by a highly relativistic jet. The H-band flux observed with HST 9.41 days after burst is that expected from the measured late-time X-ray afterglow. The late-time flare/rebrightening of the NIR-optical afterglow of SHB 130603B could have been produced also by jet collision with an interstellar density bump. Moreover, SHB plus a kilonova can be produced also by the collapse of a compact star (neutron star, strange star, or quark star to a more compact object due to cooling, loss of angular momentum, or mass accretion.

  5. Luminescence properties of Sm{sup 3+}-doped Sr{sub 3}Sn{sub 2}O{sub 7} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Lei Bingfu, E-mail: tleibf@jnu.edu.cn [Department of Physics, Jinan University, Guangzhou 510632 (China); Department of Chemistry and Nanochemistry Institute, Jinan University, Guangzhou 510632 (China); Man Shiqing [Department of Chemistry and Nanochemistry Institute, Jinan University, Guangzhou 510632 (China); Department of Electronic Engineering, Jinan University, Guangzhou 510632 (China); Liu Yingliang [Department of Chemistry and Nanochemistry Institute, Jinan University, Guangzhou 510632 (China); Yue Song [Department of Physics, Jinan University, Guangzhou 510632 (China)

    2010-12-01

    We report on a luminescent phenomenon in Sm{sup 3+}-doped Sr{sub 3}Sn{sub 2}O{sub 7} afterglow phosphor. XRD, photoluminescence, afterglow emission spectra and long-lasting phosphorescence decay curve are used to characterize this phosphor. After irradiation by a 267-nm UV light for 5 min, the Sm{sup 3+}-doped Sr{sub 3}Sn{sub 2}O{sub 7} phosphor emits intense reddish-orange emitting afterglow from the {sup 4}G{sub 5/2} to {sup 6}H{sub J} (J = 5/2, 7/2, 9/2) transitions, and its afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source. Photoluminescence spectra reveal that the reddish-orange light-emitting long-lasting phosphorescence originate from the mixture of Sm{sup 3+} characteristic transitions. The afterglow decay curve of the Sm{sup 3+}-doped Sr{sub 3}Sn{sub 2}O{sub 7} phosphor contains a fast decay component and another slow decay one. The possible mechanism of this reddish-orange light-emitting LLP phosphor is also discussed based on the experiment results.

  6. Identifying the Location in the Host Galaxy of Short GRB 1111l7A with the Chandra Sub- Arcsecond Position

    Science.gov (United States)

    Sakamoto, Takanori; Troja, E.; Aoki, K.; Guiriec, S.; Im, M.; Leloudas, G.; Malesani, D.; Melandri, A.; deUgartePostigo, A.; Urata, Y.; hide

    2012-01-01

    We present our successful program using Chandra for identifying the X-ray afterglow with sub-arcsecond accuracy for the short GRB 111117A d iscovered by Swift and Fermi. Thanks to our rapid target of opportuni ty request, Chandra clearly detected the X-ray afterglow, whereas no optical afterglow was found in deep optical observations. Instead, we clearly detect the host galaxy in optica; and also in near-infrared b ands. We found that the best photometric redshift fitofthe host is z = 1.31:(+0.46/-0.23) (90% confidence), making it one of the highest redshift short GRBs. Furthermore, we see an offset of 1.0+/-O.2 arcseco nds, which corresponds to 8.4+/-1.7 kpc aSBuming z= 1.31, between the host and the afterglow position. We discuss the importance of using Chandra for obtaining sub-arcsecond localization of the afterglow in X -rays for short GRBs to study GRB environments in great detail.

  7. Direct current plasma jet at atmospheric pressure operating in nitrogen and air

    Science.gov (United States)

    Deng, X. L.; Nikiforov, A. Yu.; Vanraes, P.; Leys, Ch.

    2013-01-01

    An atmospheric pressure direct current (DC) plasma jet is investigated in N2 and dry air in terms of plasma properties and generation of active species in the active zone and the afterglow. The influence of working gases and the discharge current on plasma parameters and afterglow properties are studied. The electrical diagnostics show that discharge can be sustained in two different operating modes, depending on the current range: a self-pulsing regime at low current and a glow regime at high current. The gas temperature and the N2 vibrational temperature in the active zone of the jet and in the afterglow are determined by means of emission spectroscopy, based on fitting spectra of N2 second positive system (C3Π-B3Π) and the Boltzmann plot method, respectively. The spectra and temperature differences between the N2 and the air plasma jet are presented and analyzed. Space-resolved ozone and nitric oxide density measurements are carried out in the afterglow of the jet. The density of ozone, which is formed in the afterglow of nitrogen plasma jet, is quantitatively detected by an ozone monitor. The density of nitric oxide, which is generated only in the air plasma jet, is determined by means of mass-spectroscopy techniques.

  8. The X-ray Telescope for the SWIFT Gamma-Ray Burst Mission

    International Nuclear Information System (INIS)

    Wells, A.; Abbey, A.F.; Beardmore, A.; Mukerjee, K.; Osborne, J.P.; Watson, D.J.; Willingale, R.; Burrows, D. N.; Hill, J. E.; Nousek, J.A.; Miles, B.J.; Mori, K.; Morris, D.C.; Zugger, M.; Chincarini, G.; Campana, S.; Citterio, O.; Moretti, A.; Tagliaferri, G.; Bosworth, J.

    2004-01-01

    The X-ray Telescope (XRT) for the SWIFT mission, built by the international consortium from Pennsylvania State University (United States), University of Leicester (UK) and Osservatorio Astronomico di Brera (Italy), is already installed on the SWIFT spacecraft. The XRT has two key functions on SWIFT; to determine locations of GRBs to better than 5 arc seconds within 100 seconds of initial detection of a burst and to measure spectra and light curves of the X-ray afterglow over around four orders of magnitude of decay in the afterglow intensity. This paper summarises the XRT performance, operating modes and sensitivity for the detection of prompt and extended X-ray afterglows from gamma-ray bursts. The performance characteristics have been determined from data taken during the ground calibration campaign at MPE's Panter facility in September 2002

  9. Chameleon fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Brax, Philippe [Institut de Physique Théorique, CEA, IPhT, CNRS, URA 2306, F-91191Gif/Yvette Cedex (France); Upadhye, Amol, E-mail: philippe.brax@cea.fr, E-mail: aupadhye@anl.gov [Institute for the Early Universe, Ewha University, International Education, Building #601, 11-1, Daehyun-Dong Seodaemun-Gu, Seoul 120-750 (Korea, Republic of)

    2014-02-01

    A scalar field dark energy candidate could couple to ordinary matter and photons, enabling its detection in laboratory experiments. Here we study the quantum properties of the chameleon field, one such dark energy candidate, in an ''afterglow'' experiment designed to produce, trap, and detect chameleon particles. In particular, we investigate the possible fragmentation of a beam of chameleon particles into multiple particle states due to the highly non-linear interaction terms in the chameleon Lagrangian. Fragmentation could weaken the constraints of an afterglow experiment by reducing the energy of the regenerated photons, but this energy reduction also provides a unique signature which could be detected by a properly-designed experiment. We show that constraints from the CHASE experiment are essentially unaffected by fragmentation for φ{sup 4} and 1/φ potentials, but are weakened for steeper potentials, and we discuss possible future afterglow experiments.

  10. Application prospects of cadmium-containing crystals based on tungstates and double tungstates

    CERN Document Server

    Nagornaya, L; Apanasenko, A; Tupitsyna, I; Chernikov, V; Vostretsov, V

    2002-01-01

    Tungstate and double tungstate crystals of high scintillation efficiency and detectors based on them are applied widely in the medical imaging and radiation monitoring because of their high sensitivity to the ionizing radiation, small radiation length, high radiation hardness, low afterglow level. In this work a possibility to broaden the application field of CWO crystals have been investigated by improvement of their spectrometric quality and decreasing of their afterglow level. CWO crystals with improved characteristics have been obtained (resolution for sup 1 sup 3 sup 7 Cs <8%, afterglow <0.02% after 20 ms). A possibility is considered to use these crystals for spectrometry of thermal and resonance neutrons, which is possible due to the presence of nuclei with large cross-section for these neutrons in the crystal lattice. Compounds of a new type based on Cd, La-containing double tungstates doped with rare earth elements have been synthesized, and their luminescent characteristics have been studied. ...

  11. Intense source of spin-polarized electrons using laser-induced optical pumping

    International Nuclear Information System (INIS)

    Gray, L.G.; Giberson, K.W.; Cheng, C.; Keiffer, R.S.; Dunning, F.B.; Walters, G.K.

    1983-01-01

    A source of spin-polarized electrons based on a laser-pumped flowing helium afterglow is described. He(2 3 S) atoms contained in the afterglow are optically pumped using circularly polarized 1.08-μm (2 3 S→2 3 P) radiation provided by a NaF (F 2+ )( color-center laser. Spin angular momentum conservation in subsequent chemi-ionization reactions with CO 2 produces polarized electrons that are extracted from the afterglow. At low currents, < or approx. =1 μA, polarizations of approx.70%--80% are achieved. At higher currents the polarization decreases, falling to approx.40% at 50 μA. The spin polarization can be simply reversed (P→-P) and the source is suitable for use in the majority of low-energy spin-dependent scattering experiments proposed to date

  12. Chameleon fragmentation

    International Nuclear Information System (INIS)

    Brax, Philippe; Upadhye, Amol

    2014-01-01

    A scalar field dark energy candidate could couple to ordinary matter and photons, enabling its detection in laboratory experiments. Here we study the quantum properties of the chameleon field, one such dark energy candidate, in an ''afterglow'' experiment designed to produce, trap, and detect chameleon particles. In particular, we investigate the possible fragmentation of a beam of chameleon particles into multiple particle states due to the highly non-linear interaction terms in the chameleon Lagrangian. Fragmentation could weaken the constraints of an afterglow experiment by reducing the energy of the regenerated photons, but this energy reduction also provides a unique signature which could be detected by a properly-designed experiment. We show that constraints from the CHASE experiment are essentially unaffected by fragmentation for φ 4 and 1/φ potentials, but are weakened for steeper potentials, and we discuss possible future afterglow experiments

  13. Heterogeneity in Short Gamma-Ray Bursts

    Science.gov (United States)

    Norris, Jay P.; Gehrels Neil; Scargle, Jeffrey D.

    2011-01-01

    We analyze the Swift/BAT sample of short gamma-ray bursts, using an objective Bayesian Block procedure to extract temporal descriptors of the bursts' initial pulse complexes (IPCs). The sample comprises 12 and 41 bursts with and without extended emission (EE) components, respectively. IPCs of non-EE bursts are dominated by single pulse structures, while EE bursts tend to have two or more pulse structures. The medians of characteristic timescales - durations, pulse structure widths, and peak intervals - for EE bursts are factors of approx 2-3 longer than for non-EE bursts. A trend previously reported by Hakkila and colleagues unifying long and short bursts - the anti-correlation of pulse intensity and width - continues in the two short burst groups, with non-EE bursts extending to more intense, narrower pulses. In addition we find that preceding and succeeding pulse intensities are anti-correlated with pulse interval. We also examine the short burst X-ray afterglows as observed by the Swift/XRT. The median flux of the initial XRT detections for EE bursts (approx 6 X 10(exp -10) erg / sq cm/ s) is approx > 20 x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts (approx 60,000 s) is approx 30 x longer than for non-EE bursts. The tendency for EE bursts toward longer prompt-emission timescales and higher initial X-ray afterglow fluxes implies larger energy injections powering the afterglows. The longer-lasting X-ray afterglows of EE bursts may suggest that a significant fraction explode into more dense environments than non-EE bursts, or that the sometimes-dominant EE component efficiently p()wers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  14. HETEROGENEITY IN SHORT GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Norris, Jay P.; Gehrels, Neil; Scargle, Jeffrey D.

    2011-01-01

    We analyze the Swift/BAT sample of short gamma-ray bursts, using an objective Bayesian Block procedure to extract temporal descriptors of the bursts' initial pulse complexes (IPCs). The sample is comprised of 12 and 41 bursts with and without extended emission (EE) components, respectively. IPCs of non-EE bursts are dominated by single pulse structures, while EE bursts tend to have two or more pulse structures. The medians of characteristic timescales-durations, pulse structure widths, and peak intervals-for EE bursts are factors of ∼2-3 longer than for non-EE bursts. A trend previously reported by Hakkila and colleagues unifying long and short bursts-the anti-correlation of pulse intensity and width-continues in the two short burst groups, with non-EE bursts extending to more intense, narrower pulses. In addition, we find that preceding and succeeding pulse intensities are anti-correlated with pulse interval. We also examine the short burst X-ray afterglows as observed by the Swift/X-Ray Telescope (XRT). The median flux of the initial XRT detections for EE bursts (∼6x10 -10 erg cm -2 s -1 ) is ∼>20x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts (∼60,000 s) is ∼30x longer than for non-EE bursts. The tendency for EE bursts toward longer prompt-emission timescales and higher initial X-ray afterglow fluxes implies larger energy injections powering the afterglows. The longer-lasting X-ray afterglows of EE bursts may suggest that a significant fraction explode into denser environments than non-EE bursts, or that the sometimes-dominant EE component efficiently powers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  15. Optical observations of Gamma-Ray Bursts

    International Nuclear Information System (INIS)

    Hjorth, J.; Pian, E.; Fynbo, J.P.U.

    2004-01-01

    We briefly review the status and recent progress in the field of optical observations of gamma-ray burst afterglows. We will focus on the fundamental observational evidence for the relationship between gamma-ray bursts and the final evolutionary phases of massive stars. In particular, we will address (i) gamma-ray burst host galaxies, (ii) optically dark gamma-ray burst afterglows, (iii) the gamma-ray burst-supernova connection, and (iv) the relation between X-ray flashes, gamma-ray bursts, and supernovae

  16. Alpenglow: A signature for chameleons in axionlike particle search experiments

    International Nuclear Information System (INIS)

    Ahlers, M.; Lindner, A.; Ringwald, A.; Schrempp, L.; Weniger, C.

    2008-01-01

    We point out that chameleon field theories might reveal themselves as an afterglow effect in axionlike particle search experiments due to chameleon-photon conversion in a magnetic field. We estimate the parameter space which is accessible by currently available technology and find that afterglow experiments could constrain this parameter space in a way complementary to gravitational and Casimir force experiments. In addition, one could reach photon-chameleon couplings which are beyond the sensitivity of common laser polarization experiments. We also sketch the idea of a Fabry-Perot cavity with chameleons which could increase the experimental sensitivity significantly

  17. GRBs optical follow-up observation at Lunin observatory, Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Huang, K.Y.; Ip, W.H. [Chung-Li Univ., Taiwan (China). Institute of astronomy; Urata, Y. [RIKEN, Saitama (Japan); Tokyo Institute of Technology, Tokyo (Japan). Department of Physics; Tamagawa, T.; Onda, K. [RIKEN, Saitama (Japan); Makishima, K. [RIKEN, Saitama (Japan); Tokyo Univ., Tokyo (Japan). Department of Physics

    2005-07-15

    The Lulin GRB program, using the Lulin One-meter Telescope (LOT) in Taiwan started in July 2003. Its scientific aims are to discover optical counterparts of XRFs and short and long GRBs, then to quickly observe them in multiple bands. Thirteen follow-up observations were provided by LOT between July 2003 and Feb. 2005. One host galaxy was found at GRB 031203. Two optical afterglows were detected for GRB 040924 and GRB 041006. In addition, the optical observations of GRB 031203 and a discussion of the non-detection of the optical afterglow of GRB 031203 are also reported in this article.

  18. GRBs optical follow-up observation at Lunin observatory, Taiwan

    International Nuclear Information System (INIS)

    Huang, K.Y.; Ip, W.H.; Makishima, K.; Tokyo Univ., Tokyo

    2005-01-01

    The Lulin GRB program, using the Lulin One-meter Telescope (LOT) in Taiwan started in July 2003. Its scientific aims are to discover optical counterparts of XRFs and short and long GRBs, then to quickly observe them in multiple bands. Thirteen follow-up observations were provided by LOT between July 2003 and Feb. 2005. One host galaxy was found at GRB 031203. Two optical afterglows were detected for GRB 040924 and GRB 041006. In addition, the optical observations of GRB 031203 and a discussion of the non-detection of the optical afterglow of GRB 031203 are also reported in this article

  19. Kiso observations of 20 GRBs in the HETE-2 era

    International Nuclear Information System (INIS)

    Urata, Y.; Tamagawa, T.; Makishima, K.; Tokyo Univ., Tokyo

    2005-01-01

    We established a GRB follow-up observation system at the Kiso observatory (Japan) in 2001. Since prior to this the east Asian area has been a blank for a GRB follow-up observational network, this observational system is very important for studying the temporal and spectral evolution of early afterglows. We have thus been able to make quick observations of early phase optical afterglows based on HETE-2 and INTEGRAL alerts. Thanks to this quick follow-up observational system, we have so far been able to use the Kiso observatory to monitor 20 events, and conduct follow-up observations in the optical and near-infrared wavelengths

  20. Kiso observations of 20 GRBs in the HETE-2 era

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Y. [RIKEN, Saitama (Japan); Tokyo Institute of Technology, Tokyo (Japan). Department of Physics; Nakada, Y.; Miyata, T.; Aoki, T.; Soyano, T.; Tarusawa, K.; Mito, H. [Kiso Observatory, Nagano (Japan); Tamagawa, T. [RIKEN, Saitama (Japan); Makishima, K. [RIKEN, Saitama (Japan); Tokyo Univ., Tokyo (Japan). Department of Physics

    2005-07-15

    We established a GRB follow-up observation system at the Kiso observatory (Japan) in 2001. Since prior to this the east Asian area has been a blank for a GRB follow-up observational network, this observational system is very important for studying the temporal and spectral evolution of early afterglows. We have thus been able to make quick observations of early phase optical afterglows based on HETE-2 and INTEGRAL alerts. Thanks to this quick follow-up observational system, we have so far been able to use the Kiso observatory to monitor 20 events, and conduct follow-up observations in the optical and near-infrared wavelengths.

  1. Alpenglow. A signature for chameleons in axion-like particle search experiments

    International Nuclear Information System (INIS)

    Ahlers, M.; Lindner, A.; Ringwald, A.; Schrempp, L.; Weniger, C.

    2007-10-01

    We point out that chameleon field theories might reveal themselves as an ''afterglow'' effect in axion-like particle search experiments due to chameleon-photon conversion in a magnetic field. We estimate the parameter space which is accessible by currently available technology and find that afterglow experiments could constrain this parameter space in a way complementary to gravitational and Casimir force experiments.In addition, one could reach photon-chameleon couplings which are beyond the sensitivity of common laser polarization experiments. We also sketch the idea of a Fabry-Perot cavity with chameleons which could increase the experimental sensitivity significantly. (orig.)

  2. Investigations of Townsend discharges in neon by mass spectrometry

    International Nuclear Information System (INIS)

    Dielis, J.W.H.

    1979-01-01

    The decay frequency of Ne( 3 P 2 )-atoms has been determined at 77 K and 295 K as a function of gas density from time sampling analysis of a N + 2 -ion impurity in the afterglow of a Townsend discharge in neon. From the sampling spectra of ions in the afterglow of a Townsend discharge, mobilities of positive ions in neon have been determined as a function of the reduced electric field strength at 77 K and 295 K. From mobility data the interaction potential as a function of intermolecular distance between a N + 2 -ion and a neon atom is evaluated. (Auth.)

  3. Alpenglow. A signature for chameleons in axion-like particle search experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers, M.; Lindner, A.; Ringwald, A.; Schrempp, L.; Weniger, C.

    2007-10-15

    We point out that chameleon field theories might reveal themselves as an ''afterglow'' effect in axion-like particle search experiments due to chameleon-photon conversion in a magnetic field. We estimate the parameter space which is accessible by currently available technology and find that afterglow experiments could constrain this parameter space in a way complementary to gravitational and Casimir force experiments.In addition, one could reach photon-chameleon couplings which are beyond the sensitivity of common laser polarization experiments. We also sketch the idea of a Fabry-Perot cavity with chameleons which could increase the experimental sensitivity significantly. (orig.)

  4. Short duration gamma ray bursts

    Indian Academy of Sciences (India)

    Observations have revealed that long bursts, with recorded afterglow, tend to reside in the star forming regions of normal galaxies. Moreover, GRB 980425 ... observer is negligible due to the special relativistic time dilation. However, because of deceleration, eventually Γ−1 > θj and thereafter, sideways expansion becomes.

  5. Forming a constant density medium close to long gamma-ray burst

    NARCIS (Netherlands)

    Marle, A.J.; Langer, N.; Achterberg, A; Garia-Segura, G.

    2006-01-01

    Aims. The progenitor stars of long Gamma-Ray Bursts (GRBs) are thought to be Wolf-Rayet stars, which generate a massive and energetic wind. Nevertheless, about 25 percent of all GRB afterglows light curves indicate a constant density medium close to the exploding star. We explore various ways to

  6. Constraints on gamma-ray burst and supernova progenitors through circumstellar absorption lines : II. Post-LBV Wolf-Rayet stars

    NARCIS (Netherlands)

    Marle, A.J.; Langer, N.; Garcia-Segura, G.

    2007-01-01

    Van Marle et al. (2005) showed that circumstellar absorption lines in early Type Ib/c supernova and gamma-ray burst afterglow spectra may reveal the progenitor evolution of the exploding Wolf-Rayet star. While the quoted paper deals with Wolf-Rayet stars which evolved through a red supergiant stage,

  7. INTEGRAL and XMM-Newton observations of the weak gamma-ray burst GRB 030227

    DEFF Research Database (Denmark)

    Mereghetti, S.; Gotz, D.; Tiengo, A.

    2003-01-01

    We present International Gamma-Ray Astrophysical Laboratory ( INTEGRAL) and XMM-Newton observations of the prompt gamma-ray emission and the X-ray afterglow of GRB 030227, the first gamma-ray burst for which the quick localization obtained with the INTEGRAL Burst Alert System has led...

  8. The metallicity and dust content of a redshift 5 gamma-ray burst host galaxy

    DEFF Research Database (Denmark)

    Sparre, M.; Hartoog, O. E.; Krühler, T.

    2014-01-01

    Observations of the afterglows of long gamma-ray bursts (GRBs) allow the study of star-forming galaxies across most of cosmic history. Here we present observations of GRB 111008A from which we can measure metallicity, chemical abundance patterns, dust-to-metals ratio and extinction of the GRB host...

  9. Enhancement of CdSiO3: Tb3+ green long-lasting phosphors by co-doping with Re3+ (Re3+=Gd3+, Y3+, La3+) ions

    International Nuclear Information System (INIS)

    Zeng, Wei; Wang, Yuhua; Han, Shaochun; Chen, Wenbo; Li, Gen

    2014-01-01

    CdSiO 3 : Tb 3+ , Re 3+ long-lasting phosphors were synthesized by the conventional high temperature solid-state method. A green-light phosphorescence phenomenon, which was associated with the 5 D 4 → 7 F J (J=6, 5, 4, 3) transitions of the Tb 3+ ion, was observed. Introduction of Re 3+ (Re 3+ =Gd 3+ , Y 3+ , La 3+ ) ions, which deepens the depth (E t ) or/and increases the density (n 0 ) of traps, greatly improved the afterglow properties of CdSiO 3 : Tb 3+ . Possible mechanism of CdSiO 3 : Tb 3+ , Re 3+ was discussed in this work. - Highlights: • CdSiO 3 : Tb 3+ , Re 3+ samples enrich the color of long-lasting afterglow phosphors in CdSiO 3 host. • Both the afterglow intensity and the lasting time are greatly enhanced for the co-doped samples, especially for Cd 0.96 SiO 3 : Tb 0.03 3+ , La 0.01 3+ . • Introduction of Re 3+ (Re 3+ =Gd 3+ , Y 3+ , La 3+ ) ions, which deepens the depth (E t ) or increase density(n 0 ) of traps, greatly improved the afterglow properties of CdSiO 3 : Tb 3+

  10. Detection of GRB 060927 at z = 5.47: Implications for the Use of Gamma-Ray Bursts as Probes of the End of the Dark Ages

    NARCIS (Netherlands)

    Ruiz-Velasco, A.E.; Swan, H.; Troja, E.; Malesani, D.; Fynbo, J.P.U.; Starling, R.L.C.; Xu, D.; Aharonian, F.; Akerlof, C.; Andersen, M.I.; Ashley, M.C.B.; Barthelmy, S.D.; Bersier, D.F.; Cerón, J.M.; Castro-Tirado, A.J.; Gehrels, N.; Gögüs, E.; Gorosabel, J.; Guidorzi, C.; Güver, T.; Hjorth, J.; Horns, D.; Huang, K.Y.; Jakobsson, P.; Jensen, B.L.; Kiziloglu, Ü.; Kouveliotou, C.; Krimm, H.A.; Ledoux, C.; Levan, A.J.; Marsh, T.; McKay, T.; Melandri, A.; Milvang-Jensen, B.; Mundell, C.G.; O'Brien, P.T.; Özel, M.; Phillips, A.; Quimby, R.; Rowell, G.; Rujopakarn, W.; Rykoff, E.S.; Schaefer, B.E.; Sollerman, J.; Tanvir, N.R.; Thöne, C.C.; Urata, Y.; Vestrand, W.T.; Vreeswijk, P.M.; Watson, D.; Wheeler, J.C.; Wijers, R.A.M.J.; Wren, J.; Yost, S.A.; Yuan, F.; Zhai, M.; Zheng, W.K.

    2007-01-01

    We report on follow-up observations of the gamma-ray burst GRB 060927 using the robotic ROTSE-IIIa telescope and a suite of larger aperture ground-based telescopes. An optical afterglow was detected 20 s after the burst, the earliest rest-frame detection of optical emission from any GRB.

  11. New semiconductor scintillators ZnSe(Te,O) and integrated radiation detectors based thereon

    NARCIS (Netherlands)

    Ryzhikov, [No Value; Starzhinskiy, N; Gal'chinetskii, L; Gashin, P; Kozin, D; Danshin, E

    Data are presented on properties of a new type of scintillator based on isovalently doped crystals of zinc selenide. Depending upon concentration of activating dopants Te and O, the wavelength of the luminescence maximum is 590-640 nm, response time is 1-50 mus, and afterglow level after 5 ms is not

  12. Scintillator materials

    International Nuclear Information System (INIS)

    1976-01-01

    The invention describes the chemical preparation of inorganic phosphors, i.e. cerium- and praseodymium pentaphosphate. The advantages, as compared to usual phosphors, are improved optical properties and a shorter duration (12 ns) of the afterglow. A discussion of various applications, e.g. in diode tubes, cathode ray tubes, gas discharge tubes, in electroluminescence, and in electron microscopes are given

  13. Hydrothermal synthesis of CdWO nanorods and their ...

    African Journals Online (AJOL)

    NICO

    CdWO4 has a high refractive index, a high X-ray absorption coefficient, low radiation damage, high luminescence intensity and low afterglow to .... atomic number ratio of the elements of Cd, W and O is approxi- mately 1:1:4 and is consistent ...

  14. Influence of the collisional recombination on the electrostatic fluctuation spectrum in an helium plasma

    International Nuclear Information System (INIS)

    Baravian, G.; Bretagne, J.; Godart, J.; Sultan, G.

    1975-01-01

    The collisional recombination, in the afterglow of a dense plasma, is regarded as a source process for an overpopulation of the high energy tail of the electron velocity distribution function. The perturbation of the distribution function leads to an important enhancement of the fluctuations of the electrostatic field in a narrow range near the plasma frequency ωsub(p). (orig.) [de

  15. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Even though radio band is the least explored of the afterglow spectrum, it has played an important role in the progress of GRB physics, specifically in confirming the hypothesized relativistic effects. Currently radio astronomy is in the beginning of a revolution. The high sensitive Square Kilometer Array (SKA) is being planned ...

  16. Solving the Mystery of the Short-Hard Gamma-Ray Bursts

    Science.gov (United States)

    Fox, Derek

    2005-07-01

    Eight years after the afterglow detections that revolutionized studies of the long-soft gamma-ray bursts, not even one afterglow of a short-hard GRB has been seen, and the nature of these events has become one of the most important problems in GRB research. The Swift satellite, expected to be in full operation throughout Cycle 14, will report few-arcsecond localizations for short-hard bursts in minutes, enabling prompt, deep optical afterglow searches for the first time. Discovery and observation of the first short-hard optical afterglows will answer most of the critical questions about these events: What are their distances and energies? Do they occur in distant galaxies, and if so, in which regions of those galaxies? Are they the result of collimated or quasi-spherical explosions? In combination with an extensive rapid-response ground-based campaign, we propose to make the critical high-sensitivity HST TOO observations that will allow us to answer these questions. If theorists are correct in attributing the short-hard bursts to binary neutron star coalescence events, then they will serve as signposts to the primary targeted source population for ground-based gravitational-wave detectors, and short-hard burst studies will have a vital role to play in guiding those observations.

  17. Some remarks on the microdischarge development in dielectric barrier discharges

    International Nuclear Information System (INIS)

    Kozlov, K.; Pietsch, G.

    1998-01-01

    In addition to the microdischarge development phases which have been known before, two other, optically observable phases can be distinguished, viz. (i) pre-breakdown anode glow, and (ii) afterglow phase. The latter can be interpreted as resulting from recombination processes. (author)

  18. A non-invasive, on-line deuterium dilution technique for the measurement of total body water in haemodialysis patients

    Czech Academy of Sciences Publication Activity Database

    Chan, C.; Smith, D.; Španěl, Patrik; McIntyre, Ch. W.; Davies, S. J.

    2008-01-01

    Roč. 23, č. 6 (2008), s. 2064-2070 ISSN 0931-0509 Institutional research plan: CEZ:AV0Z40400503 Keywords : flowing after-glow mass spectrometer (FA-MS) * body composition * deuterium dilution Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.568, year: 2008

  19. Testing and Performance of UFFO Burst Alert & Trigger Telescope

    DEFF Research Database (Denmark)

    Rípa, Jakub; Bin Kim, Min; Lee, Jik

    2014-01-01

    The Ultra-Fast Flash Observatory pathfinder (UFFO-p) is a new space mission dedicated to detect Gamma-Ray Bursts (GRBs) and rapidly follow their afterglows in order to provide early optical/ultraviolet measurements. A GRB location is determined in a few seconds by the UFFO Burst Alert & Trigger t...

  20. Kinetics of Ar+*(2G9/2) metastable ions and transport of argon ions in ICP reactor

    NARCIS (Netherlands)

    Sadeghi, N.; Derouard, J.; Grift, van de M.; Kroesen, G.M.W.; Hoog, de F.J.; Tachibana, K.; Watanabe, Y.

    1997-01-01

    The decay time of the argon Ar~~(2G912) metastable ions was measured in the afterglow of a low pressure pulsed helicon reactor. From the argon pressure and electron density dependence of this decay time, rate coefficients for quenching of these ions by argon atoms and by plasma electrons have been

  1. Millimetre observations of gamma-ray bursts at IRAM

    DEFF Research Database (Denmark)

    Castro-Tirado, A. J.; Bremer, M.; Winters, J. M.

    2013-01-01

    Since 1997, and following our detection of the first mm afterglow, we have followed-up 70 GRBs, mainly with the IRAMÅ Plateau de Bure Interferometer, what can be considered as the IRAM Legacy GRB Sample. 66 events were observed at 3 mm, with 19 of them being detected (with another 3 having margin...

  2. A metal-rich molecular cloud surrounds GRB 050904 at redshift 6.3

    NARCIS (Netherlands)

    Campana, S.; Lazzati, D.; Ripamonti, Emanuele; Perna, R.; Covino, S.; Tagliaferri, G.; Moretti, A.; Romano, P.; Cusumano, G.; Chincarini, G.

    2007-01-01

    GRB 050904 is the gamma-ray burst with the highest measured redshift. We performed time-resolved X-ray spectroscopy of the late GRB and early afterglow emission. We find robust evidence for a decrease with time of the soft X-ray-absorbing column. We model the evolution of the column density due to

  3. Intumescent all-polymer multilayer nanocoating capable of extinguishing flame on fabric

    Science.gov (United States)

    Cotton fabric was treated with flame-retardant coatings composed of poly (sodium phosphate), PSP, which acts as the acid source, and poly (allylamine), PAAm, which is used as the blowing agent, prepared via layer-by-layer (LbL) assembly. By applying these thin coating on fabric, after-glow is elimi...

  4. Clustering of galaxies around gamma-ray burst sight-lines

    DEFF Research Database (Denmark)

    Sudilovsky, V.; Greiner, J.; Rau, A.

    2013-01-01

    -lines, as strong MgII tends to trace these sources. In this work, we test this expectation by calculating the two point angular correlation function of galaxies within 120'' (~470 h Kpc470h71-1Kpc at z ~ 0.4) of GRB afterglows. We compare the gamma-ray burst optical and near-infrared detector (GROND) GRB afterglow.......3. This result is contrary to the expectations from the MgII excess derived from GRB afterglow spectroscopy, although many confirmed galaxy counterparts to MgII absorbers may be too faint to detect in our sample-especially those at z > 1. We note that the addition of higher sensitivity Spitzer/IRAC or HST/WFC3......There is evidence of an overdensity of strong intervening MgII absorption line systems distributed along the lines of sight toward gamma-ray burst (GRB) afterglows relative to quasar sight-lines. If this excess is real, one should also expect an overdensity of field galaxies around GRB sight...

  5. Metal-atom fluorescence from the quenching of metastable rare gases by metal carbonyls

    International Nuclear Information System (INIS)

    Hollingsworth, W.E.

    1982-11-01

    A flowing afterglow apparatus was used to study the metal fluorescence resulting from the quenching of metastable rare-gas states by metal carbonyls. The data from the quenching or argon, neon, and helium by iron and nickel carbonyl agreed well with a restricted degree of freedom model indicating a concerted bond-breaking dissociation

  6. Very high column density and small reddening toward GRB 020124 at z=3.20

    DEFF Research Database (Denmark)

    Hjorth, J.; Møller, Per; Gorosabel, J.

    2003-01-01

    We present optical and near-infrared observations of the dim afterglow of GRB 020124, obtained between 2 and 68 hr after the gamma-ray burst. The burst occurred in a very faint (Rgreater than or similar to29.5) damped Lyalpha absorber (DLA) at a redshift of z=3.198+/-0.004. The derived column...

  7. A Bulk Comptonization Model for the Prompt GRM Emission

    Science.gov (United States)

    Kazanas, Demos; Mastichiadis, A.

    2010-01-01

    The "Supercritical Pile" is a very economical GRB model that provides for the efficient conversion of the energy stored in the protons of a Relativistic Blast Wave (RBW) into radiation and at the same time produces - in the prompt GRB phase, even in the absence of any particle acceleration - a spectral peak at energy approximately 1 MeV. We extend this model to include the evolution of the RBW Lorentz factor F and thus follow its spectral and temporal features into the early GRB afterglow stage. One of the novel features of the present treatment is the inclusion of the feedback of the GRB produced radiation on the evolution of Gamma with radius. This feedback and the presence of kinematic and dynamic thresholds in the model are sources of potentially very rich time evolution which we have began to explore. In particular, one can this way obtain afterglow light curves with steep decays followed by the more conventional flatter afterglow slopes, while at the same time preserving the desirable features of the model, i.e. the well defined relativistic electron source and radiative processes that produce the proper peak in the nu F(sub nu) spectra. In this note we present the results of a specific set of parameters of this model with emphasis on the multiwavelength prompt emission and transition to the early afterglow.

  8. Activation of Methane by FeO+: Determining Reaction Pathways through Temperature-Dependent Kinetics and Statistical Modeling (Postprint)

    Science.gov (United States)

    2014-02-25

    reacting species, and α is the isotropic polarizability of the neutral. One can show that the approximation L ≈ J under the present conditions is...Afterglow Studies of Organic Positive Ions Generated by Penning Ionization Using Metastable Argon Atoms. Int. J. Mass Spectrom. 1983, 52, 65−94. (44

  9. Progress report of 1974

    International Nuclear Information System (INIS)

    Blanc, Daniel.

    1974-01-01

    Research work carried out at the CPAT is presented. It covers the following fields: atomic collisions, afterglow in gases, d.c. electric discharges in gases at intermediate and high pressures, electric arcs, dielectrics, and radiation transport in matter. The physics of aerosols and atmospheric exchanges is also studied [fr

  10. Time-dependent excitation and ionization modelling of absorption-line variability due to GRB080310

    DEFF Research Database (Denmark)

    Vreeswijk, P.M.; De Cia, A.; Jakobsson, P.

    2013-01-01

    .42743. To estimate the rest-frame afterglow brightness as a function of time, we use a combination of the optical VRI photometry obtained by the RAPTOR-T telescope array, which is presented in this paper, and Swift's X-Ray Telescope (XRT) observations. Excitation alone, which has been successfully applied...

  11. Suppression of Tritium Retention in Remote Areas of ITER by Nonperturbative Reactive Gas Injection

    NARCIS (Netherlands)

    Tabares, F. L.; Ferreira, J. A.; Ramos, A.; van Rooij, G. J.; Westerhout, J.; Al, R.; Rapp, J.; Drenik, A.; Mozetic, M.

    2010-01-01

    A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4 nm/min

  12. 235U isotope enrichment in the metastable levels of UI

    International Nuclear Information System (INIS)

    Gagne, J.M.; Demers, Y.; Dreze, C.; Pianarosa, P.

    1983-01-01

    We have used optical pumping to produce a substantial 235 U enrichment in the metastable levels of UI in the discharge afterglow of a hollow-cathode vapor generator. The measured isotope-enrichment factor for the level at 3800 cm -1 is approximately 20

  13. GRB follow-up observations in the East-Asian region

    International Nuclear Information System (INIS)

    Tamagawa, T.; Urata, Y.; Tokyo Institute of Technology, Tokyo; Huang, K. Y.; Ip, W.H.; Qiu, Y.; Hu, J.Y.; Zhou, Xn.; Onda, K.; Tokyo Univ. of Sciences, Tokyo; Makishima, K.; Tokyo Univ., Tokyo

    2005-01-01

    In 2004, we established a Japan-Taiwan-China collaboration for GBR study in the East-Asian region. This serves as a valuable addiction to the world-wide optical and infrared follow-up network, because the East-Asia region would otherwise be blank. We have been carrying out imaging and spectroscopy follow-up observations at Lulin (Taiwan), Kiso (Japan), WIDGET (Japan) and Xinglong (China). From Xinglong and Kiso, we can locate candidates and obtain early time spectra for afterglows. While WIDGET provides early time observations before the bursts, the high-time resolution for multi-band light curves can be obtained at Lulin. With the data from these sites, we can obtain detailed information about the light curve and redshift of GRBs, which are important to understand the mechanism of the afterglows. Up to March 2005, ten follow-up observations have been provided by this East-Asia cooperation. Two optical afterglows were detected, GRB 040924 and GRB 041006. The results of the two detected afterglows are reported in this paper

  14. GRB follow-up observations in the East-Asian region

    Energy Technology Data Exchange (ETDEWEB)

    Tamagawa, T. [RIKEN, Saitama (Japan); Urata, Y. [RIKEN, Saitama (Japan); Tokyo Institute of Technology, Tokyo (Japan). Department of Physics; Huang, K. Y.; Ip, W.H. [National Centre University, Tokyo (Japan). Institute of Astronomy; Qiu, Y.; Hu, J.Y.; Zhou, Xn. [Chinese Academy of Sciences, Beijing (China). National Astronomical Observatoires; Onda, K. [RIKEN, Saitama (Japan); Tokyo Univ. of Sciences, Tokyo (Japan). Department of Physics; Makishima, K. [RIKEN, Saitama (Japan); Tokyo Univ., Tokyo (Japan). Department of Physics

    2005-07-15

    In 2004, we established a Japan-Taiwan-China collaboration for GBR study in the East-Asian region. This serves as a valuable addiction to the world-wide optical and infrared follow-up network, because the East-Asia region would otherwise be blank. We have been carrying out imaging and spectroscopy follow-up observations at Lulin (Taiwan), Kiso (Japan), WIDGET (Japan) and Xinglong (China). From Xinglong and Kiso, we can locate candidates and obtain early time spectra for afterglows. While WIDGET provides early time observations before the bursts, the high-time resolution for multi-band light curves can be obtained at Lulin. With the data from these sites, we can obtain detailed information about the light curve and redshift of GRBs, which are important to understand the mechanism of the afterglows. Up to March 2005, ten follow-up observations have been provided by this East-Asia cooperation. Two optical afterglows were detected, GRB 040924 and GRB 041006. The results of the two detected afterglows are reported in this paper.

  15. Using gamma-ray bursts to probe the cosmic intergalactic medium

    International Nuclear Information System (INIS)

    Sudilovsky, Vladimir

    2014-01-01

    Gamma-ray bursts (GRBs) rapidly liberate enormous amounts of energy through the cataclysmic destruction of an individual massive object. GRBs are the most energetic events in the Universe, boasting isotropic equivalent energy releases of E∝10 51-54 erg in time scales of seconds - more energy than even active galaxies in the same time-frame. These transient events represent the ultimate high energy laboratories, and their afterglows are readily detectable from ground-based observatories out to cosmological distances out to z∝8. For this reason, GRBs are a natural tool to probe the early universe. To this end, programs to quickly measure the photometric and spectroscopic properties of GRB afterglows are providing a wealth of data that enable us to characterize the physical properties of both the burst itself and its host environment. In addition to providing extremely poignant information on the burst and its medium, GRB afterglow spectra show the presence of matter intervening along the line of sight. MgII, an important tracer of α-element processes and thus of star formation and galaxies, has been measured in ∝ 60% of GRB afterglow spectra. Surprisingly, MgII is only found in ∝30% of quasar spectra. This discrepancy in the number density dn/dz of intervening MgII absorbers implies that there are significant observational biases in either the spectroscopic samples of either GRB afterglows or quasars. In this work, we review the MgII issue and the biases proposed to explain it. We find that observations of other tracer systems (namely CIV) do not show the same overdensity, and thus conclude that solution to the MgII problem is related to the geometry of the sight-line relative to the absorbers. We conclude that an observational bias stemming from dust extinction arising from MgII cannot explain such a large discrepancy. Finally, we search for a signal of the MgII discrepancy in the transverse direction by computing the GRB-galaxy two point correlation

  16. Using gamma-ray bursts to probe the cosmic intergalactic medium

    Energy Technology Data Exchange (ETDEWEB)

    Sudilovsky, Vladimir

    2014-05-28

    Gamma-ray bursts (GRBs) rapidly liberate enormous amounts of energy through the cataclysmic destruction of an individual massive object. GRBs are the most energetic events in the Universe, boasting isotropic equivalent energy releases of E∝10{sup 51-54} erg in time scales of seconds - more energy than even active galaxies in the same time-frame. These transient events represent the ultimate high energy laboratories, and their afterglows are readily detectable from ground-based observatories out to cosmological distances out to z∝8. For this reason, GRBs are a natural tool to probe the early universe. To this end, programs to quickly measure the photometric and spectroscopic properties of GRB afterglows are providing a wealth of data that enable us to characterize the physical properties of both the burst itself and its host environment. In addition to providing extremely poignant information on the burst and its medium, GRB afterglow spectra show the presence of matter intervening along the line of sight. MgII, an important tracer of α-element processes and thus of star formation and galaxies, has been measured in ∝ 60% of GRB afterglow spectra. Surprisingly, MgII is only found in ∝30% of quasar spectra. This discrepancy in the number density dn/dz of intervening MgII absorbers implies that there are significant observational biases in either the spectroscopic samples of either GRB afterglows or quasars. In this work, we review the MgII issue and the biases proposed to explain it. We find that observations of other tracer systems (namely CIV) do not show the same overdensity, and thus conclude that solution to the MgII problem is related to the geometry of the sight-line relative to the absorbers. We conclude that an observational bias stemming from dust extinction arising from MgII cannot explain such a large discrepancy. Finally, we search for a signal of the MgII discrepancy in the transverse direction by computing the GRB-galaxy two point correlation

  17. Go Long, Go Deep: Finding Optical Jet Breaks for Swift-Era GRBs with the LBT

    Science.gov (United States)

    Dai, X.; Garnavich, P. M.; Prieto, J. L.; Stanek, K. Z.; Kochanek, C. S.; Bechtold, J.; Bouche, N.; Buschkamp, P.; Diolaiti, E.; Fan, X.; Giallongo, E.; Gredel, R.; Hill, J. M.; Jiang, L.; McClelland, C.; Milne, P.; Pedichini, F.; Pogge, R. W.; Ragazzoni, R.; Rhoads, J.; Smareglia, R.; Thompson, D.; Wagner, R. M.

    2008-08-01

    Using the 8.4 m Large Binocular Telescope, we observed six GRB afterglows from 2.8 hr to 30.8 days after the burst triggers to systematically probe the late-time behaviors of afterglows including jet breaks, flares, and supernova bumps. We detected five afterglows with Sloan r' magnitudes ranging from 23.0 to 26.3 mag. The depth of our observations allows us to extend the temporal baseline for measuring jet breaks by another decade in timescale. We detected two jet breaks and a third candidate, all of which are not detectable without deep, late-time optical observations. In the other three cases, we do not detect the jet breaks either because of contamination from the host galaxy light, the presence of a supernova bump, or the intrinsic faintness of the optical afterglow. This suggests that the basic picture that GRBs are collimated is still valid and that the apparent lack of Swift jet breaks is due to poorly sampled afterglow light curves, particularly at late times. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; the Ohio State University; and the Research Corporation, on behalf of the University of Notre Dame, the University of Minnesota, and the University of Virginia.

  18. Gamma Ray Bursts - Observations

    Science.gov (United States)

    Gehrels, N.; Cannizzo, J. K.

    2010-01-01

    We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high energy emission.

  19. Polarized Emission from Gamma-Ray Burst Jets

    Directory of Open Access Journals (Sweden)

    Shiho Kobayashi

    2017-11-01

    Full Text Available I review how polarization signals have been discussed in the research field of Gamma-Ray Bursts (GRBs. I mainly discuss two subjects in which polarimetry enables us to study the nature of relativistic jets. (1 Jet breaks: Gamma-ray bursts are produced in ultra-relativistic jets. Due to the relativistic beaming effect, the emission can be modeled in a spherical model at early times. However, as the jet gradually slows down, we begin to see the edge of the jet together with polarized signals at some point. (2 Optical flash: later time afterglow is known to be insensitive to the properties of the original ejecta from the GRB central engine. However, a short-lived, reverse shock emission would enable us to study the nature of of GRB jets. I also briefly discuss the recent detection of optical circular polarization in GRB afterglow.

  20. A short gamma-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225.

    Science.gov (United States)

    Gehrels, N; Sarazin, C L; O'Brien, P T; Zhang, B; Barbier, L; Barthelmy, S D; Blustin, A; Burrows, D N; Cannizzo, J; Cummings, J R; Goad, M; Holland, S T; Hurkett, C P; Kennea, J A; Levan, A; Markwardt, C B; Mason, K O; Meszaros, P; Page, M; Palmer, D M; Rol, E; Sakamoto, T; Willingale, R; Angelini, L; Beardmore, A; Boyd, P T; Breeveld, A; Campana, S; Chester, M M; Chincarini, G; Cominsky, L R; Cusumano, G; de Pasquale, M; Fenimore, E E; Giommi, P; Gronwall, C; Grupe, D; Hill, J E; Hinshaw, D; Hjorth, J; Hullinger, D; Hurley, K C; Klose, S; Kobayashi, S; Kouveliotou, C; Krimm, H A; Mangano, V; Marshall, F E; McGowan, K; Moretti, A; Mushotzky, R F; Nakazawa, K; Norris, J P; Nousek, J A; Osborne, J P; Page, K; Parsons, A M; Patel, S; Perri, M; Poole, T; Romano, P; Roming, P W A; Rosen, S; Sato, G; Schady, P; Smale, A P; Sollerman, J; Starling, R; Still, M; Suzuki, M; Tagliaferri, G; Takahashi, T; Tashiro, M; Tueller, J; Wells, A A; White, N E; Wijers, R A M J

    2005-10-06

    Gamma-ray bursts (GRBs) come in two classes: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z approximately 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars. In contrast, no short GRB had been accurately (burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

  1. Early optical emission from the gamma-ray burst of 4 October 2002.

    Science.gov (United States)

    Fox, D W; Yost, S; Kulkarni, S R; Torii, K; Kato, T; Yamaoka, H; Sako, M; Harrison, F A; Sari, R; Price, P A; Berger, E; Soderberg, A M; Djorgovski, S G; Barth, A J; Pravdo, S H; Frail, D A; Gal-Yam, A; Lipkin, Y; Mauch, T; Harrison, C; Buttery, H

    2003-03-20

    Observations of the long-lived emission--or 'afterglow'--of long-duration gamma-ray bursts place them at cosmological distances, but the origin of these energetic explosions remains a mystery. Observations of optical emission contemporaneous with the burst of gamma-rays should provide insight into the details of the explosion, as well as into the structure of the surrounding environment. One bright optical flash was detected during a burst, but other efforts have produced negative results. Here we report the discovery of the optical counterpart of GRB021004 only 193 seconds after the event. The initial decline is unexpectedly slow and requires varying energy content in the gamma-ray burst blastwave over the course of the first hour. Further analysis of the X-ray and optical afterglow suggests additional energy variations over the first few days.

  2. The bright gamma-ray burst of 2000 February 10: A case study of an optically dark gamma-ray burst

    DEFF Research Database (Denmark)

    Piro, L.; Frail, D.A.; Gorosabel, J.

    2002-01-01

    The gamma-ray burst GRB 000210 had the highest gamma-ray peak flux of any event localized by BeppoSAX as yet, but it did not have a detected optical afterglow, despite prompt and deep searches down to R-lim approximate to 23.5. It is therefore one of the events recently classified as dark GRBs......, whose origin is still unclear. Chandra observations allowed us to localize the X-ray afterglow of GRB 000210 to within approximate to1", and a radio transient was detected with the Very Large Array. The precise X-ray and radio positions allowed us to identify the likely host galaxy of this burst...

  3. Broadband Study of GRB 091127: A Sub-energetic Burst at Higher Redshift?

    Science.gov (United States)

    Troja, E.; Sakamoto, T.; Guidorzi, C.; Norris, J. P.; Panaitescu, A.; Kobayashi, S.; Omodei, N.; Brown, J. C.; Burrows, D. N.; Evans, P. A.; Gehrels, N.; Marshall, F. E.; Mawson, N.; Melandri, A.; Mundell, C. G.; Oates, S. R.; Pal'shin, V.; Preece, R. D.; Racusin, J. L.; Steele, I. A.; Tanvir, N. R.; Vasileiou, V.; Wilson-Hodge, C.; Yamaoka, K.

    2012-12-01

    GRB 091127 is a bright gamma-ray burst (GRB) detected by Swift at a redshift z = 0.49 and associated with SN 2009nz. We present the broadband analysis of the GRB prompt and afterglow emission and study its high-energy properties in the context of the GRB/SN association. While the high luminosity of the prompt emission and standard afterglow behavior are typical of cosmological long GRBs, its low-energy release (E γ < 3 × 1049 erg), soft spectrum, and unusual spectral lag connect this GRB to the class of sub-energetic bursts. We discuss the suppression of high-energy emission in this burst, and investigate whether this behavior could be connected with the sub-energetic nature of the explosion.

  4. BROADBAND STUDY OF GRB 091127: A SUB-ENERGETIC BURST AT HIGHER REDSHIFT?

    Energy Technology Data Exchange (ETDEWEB)

    Troja, E.; Sakamoto, T.; Brown, J. C.; Gehrels, N.; Marshall, F. E.; Racusin, J. L. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guidorzi, C. [Physics Department, University of Ferrara, via Saragat 1, I-44122, Ferrara (Italy); Norris, J. P. [Physics Department, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Panaitescu, A. [Space Science and Applications, MS D466, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kobayashi, S.; Mawson, N.; Melandri, A.; Mundell, C. G.; Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, CH41 1LD Birkenhead (United Kingdom); Omodei, N. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Burrows, D. N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Evans, P. A. [X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Oates, S. R. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Pal' shin, V. [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St Petersburg 194021 (Russian Federation); Preece, R. D. [Department of Physics, University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); and others

    2012-12-10

    GRB 091127 is a bright gamma-ray burst (GRB) detected by Swift at a redshift z = 0.49 and associated with SN 2009nz. We present the broadband analysis of the GRB prompt and afterglow emission and study its high-energy properties in the context of the GRB/SN association. While the high luminosity of the prompt emission and standard afterglow behavior are typical of cosmological long GRBs, its low-energy release (E{sub {gamma}} < 3 Multiplication-Sign 10{sup 49} erg), soft spectrum, and unusual spectral lag connect this GRB to the class of sub-energetic bursts. We discuss the suppression of high-energy emission in this burst, and investigate whether this behavior could be connected with the sub-energetic nature of the explosion.

  5. Time-dependent plasma behavior triggered by a pulsed electron gun under conditions of beam-plasma-discharge

    International Nuclear Information System (INIS)

    Szuszczewicz, E.P.; Lin, C.S.

    1982-01-01

    This chapter reports on experiments whose purpose was to simulate spaceborne applications of energetic electron guns while exploring the ''in situ'' diagnostics of time-dependent beam-plasma behavior under pulsed electron gun conditions. Beam-plasma-discharge (BPD), the BPD afterglow that exists after gun-pulse termination, and the plasma decay process are considered. It is concluded that there is a rapid enhancement in plasma density as the gas turns on; that during the pulse-ON time a quasi-steady-state BPD can be maintained with characteristics identical with its dc counterpart; that in the period immediately following gun-pulse termination the plasma loss process is dominated by cross-field radial diffusion; and that the afterglow plasma is within + or -10% of being an isodensity contour

  6. Nuclear spin state-resolved cavity ring-down spectroscopy diagnostics of a low-temperature H3+ -dominated plasma

    International Nuclear Information System (INIS)

    Hejduk, Michal; Dohnal, Petr; Varju, Jozef; Rubovič, Peter; Plašil, Radek; Glosík, Juraj

    2012-01-01

    We have applied a continuous-wave near-infrared cavity ring-down spectroscopy method to study the parameters of a H 3 + -dominated plasma at temperatures in the range 77–200 K. We monitor populations of three rotational states of the ground vibrational state corresponding to para and ortho nuclear spin states in the discharge and the afterglow plasma in time and conclude that abundances of para and ortho states and rotational temperatures are well defined and stable. The non-trivial dependence of a relative population of para- H 3 + on a relative population of para-H 2 in a source H 2 gas is described. The results described in this paper are valuable for studies of state-selective dissociative recombination of H 3 + ions with electrons in the afterglow plasma and for the design of sources of H 3 + ions in a specific nuclear spin state. (paper)

  7. Nuclear spin state-resolved cavity ring-down spectroscopy diagnostics of a low-temperature H_3^+ -dominated plasma

    Science.gov (United States)

    Hejduk, Michal; Dohnal, Petr; Varju, Jozef; Rubovič, Peter; Plašil, Radek; Glosík, Juraj

    2012-04-01

    We have applied a continuous-wave near-infrared cavity ring-down spectroscopy method to study the parameters of a H_3^+ -dominated plasma at temperatures in the range 77-200 K. We monitor populations of three rotational states of the ground vibrational state corresponding to para and ortho nuclear spin states in the discharge and the afterglow plasma in time and conclude that abundances of para and ortho states and rotational temperatures are well defined and stable. The non-trivial dependence of a relative population of para- H_3^+ on a relative population of para-H2 in a source H2 gas is described. The results described in this paper are valuable for studies of state-selective dissociative recombination of H_3^+ ions with electrons in the afterglow plasma and for the design of sources of H_3^+ ions in a specific nuclear spin state.

  8. An experimental study of the combustion characteristics of groundnut shell and waste paper admixture briquettes

    Directory of Open Access Journals (Sweden)

    O. A. Oyelaran

    2015-12-01

    Full Text Available The study was undertaken to assess the heat released of briquettes produced from waste paper and groundnut shell admixture in five mixing ratios (90:10; 80:20; 70:30; 60:40; and 50:50. The briquettes were prepared on an existing motorized briquetting machine. The suitability of briquetted fuel as domestic fuel was studied in terms of flame propagation, afterglow, calorific value, and utilized heat, after sun drying the prepared briquettes for nineteen (19 days. The results of propagation rate and afterglow obtained for all the six compositions are satisfactory they range between 0.13 to 0.14 and 365 to 380 respectively. These energy values obtained for the whole samples are sufficient enough to produce heat required for household cooking and small scale industrial cottage applications. Finally it was observed that composition variation affects the properties of the briquettes.

  9. SHORT-DURATION GAMMA-RAY BURSTS FROM OFF-AXIS COLLAPSARS

    International Nuclear Information System (INIS)

    Lazzati, Davide; Morsony, Brian J.; Begelman, Mitchell C.

    2010-01-01

    We present two-dimensional (2D) high-resolution hydrodynamic simulations of the relativistic outflows of long-duration gamma-ray burst (GRB) progenitors. We analyze the properties of the outflows at wide off-axis angles, produced by the expansion of the hot cocoon that surrounds the jet inside the progenitor star. We find that the cocoon emission at wide angles may have properties similar to those of the subclass of short-duration GRBs with persistent X-ray emission. We compute the predicted duration distribution, redshift distribution, and afterglow brightness, and we find that they are all in agreement with the observed properties of short GRBs with persistent emission. We suggest that a supernova component, the properties of the host galaxies, and late afterglow observations can be used as a crucial test to verify this model.

  10. Improvements in phosphors

    International Nuclear Information System (INIS)

    Rabatin, J.G.

    1981-01-01

    For X-ray image converter applications, especially when used in medical radiography, it is desirable to improve the speed and brightness of response for conversion of X-rays in phosphors. The rare earth oxyhalide phosphors coactivated with a combination of rare earth activators described in this patent are capable of exhibiting low afterglow with high ultraviolet emission. They have the general formula Lnsub(1-y-w)OX:Tbsub(y)Tmsub(w) where Ln is lanthanum or gadolinium, X is chlorine and/or bromine, y is from 0.0005 to 0.010 moles per mole and w is from 0.00005 to 0.005 moles per mole of the Lnsub(1-y-w)OX host. The method of preparation and characteristics of speed, afterglow and UV emission are described. (U.K.)

  11. KSC-04PD-2187

    Science.gov (United States)

    2004-01-01

    KENNEDY SPACE CENTER, FLA. Technicians at NASAs Hangar AE, Cape Canaveral Air Force Station (CCAFS), help guide the Swift spacecraft being lowered onto a payload attach fitting, the interface between the spacecraft and the second stage of the Boeing Delta II rocket. Swift is a first-of-its-kind multi- wavelength observatory dedicated to the study of gamma-ray burst (GRB) science. Its three instruments will work together to observe GRBs and afterglows in the gamma ray, X-ray, ultraviolet and optical wavebands. Swift is expected to observe more than 200 gamma-ray bursts the most comprehensive study of GRB afterglows to date during its 2-year mission. Swift is scheduled to launch in November from Launch Pad 17-A at CCAFS.

  12. KSC-04PD-2186

    Science.gov (United States)

    2004-01-01

    KENNEDY SPACE CENTER, FLA. Technicians at NASAs Hangar AE, Cape Canaveral Air Force Station (CCAFS), help guide the Swift spacecraft being lowered onto a payload attach fitting, the interface between the spacecraft and the second stage of the Boeing Delta II rocket. Swift is a first-of-its-kind multi- wavelength observatory dedicated to the study of gamma-ray burst (GRB) science. Its three instruments will work together to observe GRBs and afterglows in the gamma ray, X-ray, ultraviolet and optical wavebands. Swift is expected to observe more than 200 gamma-ray bursts the most comprehensive study of GRB afterglows to date during its 2-year mission. Swift is scheduled to launch in November from Launch Pad 17-A at CCAFS.

  13. DR Experiments in the 60 years since the Bates paper

    International Nuclear Information System (INIS)

    Johnsen, Rainer

    2011-01-01

    About 60 years have passed since David Bates in a 1950 Physical Review Letter to the Editor first clarified the dissociative recombination mechanism (DR) of molecular ions and provided the conceptual basis for the process that plays an important role in the ionospheres of Earth and other planets, the interstellar medium, and electrical discharges. His visionary (and characteristically 'terse') thumbnail sketch of the DR mechanism only hinted at the subtleties that have kept atomic theorists and experimentalists busy for many years. In my talk, I will focus on experiments on N 2 + recombination, beginning with plasma afterglows, and then move on to the 'after'-afterglow period that is now dominated by the powerful storage-ring methods.

  14. Comparison of functional parameters of CsI:Tl crystals and thick films

    International Nuclear Information System (INIS)

    Fedorov, A.; Gektin, A.; Lebedynskiy, A.; Mateychenko, P.; Shkoropatenko, A.

    2013-01-01

    500 mkm thick CsI:Tl columnar films can be produced using thermal evaporation in vacuum by sublimation of the same bulk crystal. Comparison of afterglow and radiation stability of deposited CsI:Tl films with source crystal was the aim of current work. It is shown that the afterglow in the films is always below its level in initial single crystal. It was ascertained that the annealing atmospheres influence the processes leading to the activator depletion of the films during the thermal processing. -- Highlights: ► Thick CsI:Tl columnar films were obtained by thermal evaporation in vacuum. ► Radiation stability of such CsI:Tl films appears to be better than that of crystal. ► CsI:Tl film parameters can be modified by annealing in different atmospheres

  15. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

    OpenAIRE

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2017-01-01

    In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on ...

  16. Synchrotron self-inverse Compton radiation from reverse shock on GRB 120326A

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Yuji [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun; Takahashi, Satoko [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106, Taiwan (China); Im, Myungshin; Kim, Jae-Woo; Jang, Minsung [Center for the Exploration of the Origin of the Universe, Department of Physics and Astronomy, FPRD, Seoul National University, Shillim-dong, San 56-1, Kwanak-gu, Seoul (Korea, Republic of); Yamaoka, Kazutaka [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Tashiro, Makoto [Department of Physics, Saitama University, Shimo-Okubo, Saitama 338-8570 (Japan); Pak, Soojong, E-mail: urata@astro.ncu.edu.tw [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2014-07-10

    We present multi-wavelength observations of a typical long duration GRB 120326A at z = 1.798, including rapid observations using a Submillimeter Array (SMA) and a comprehensive monitoring in the X-ray and optical. The SMA observation provided the fastest detection to date among seven submillimeter afterglows at 230 GHz. The prompt spectral analysis, using Swift and Suzaku, yielded a spectral peak energy of E{sub peak}{sup src}=107.8{sub −15.3}{sup +15.3} keV and an equivalent isotropic energy of E{sub iso} as 3.18{sub −0.32}{sup +0.40}×10{sup 52} erg. The temporal evolution and spectral properties in the optical were consistent with the standard forward shock synchrotron with jet collimation (6.°69 ± 0.°16). The forward shock modeling, using a two-dimensional relativistic hydrodynamic jet simulation, was also determined by the reasonable burst explosion and the synchrotron radiation parameters for the optical afterglow. The X-ray light curve showed no apparent jet break and the temporal decay index relation between the X-ray and optical (αo – α{sub X} = –1.45 ± 0.10) indicated different radiation processes in each of them. Introducing synchrotron self-inverse Compton radiation from reverse shock is a possible solution, and the detection and slow decay of the afterglow in submillimeter supports that this is a plausible idea. The observed temporal evolution and spectral properties, as well as forward shock modeling parameters, enabled us to determine reasonable functions to describe the afterglow properties. Because half of the events share similar properties in the X-ray and optical as the current event, GRB 120326A will be a benchmark with further rapid follow-ups, using submillimeter instruments such as an SMA and the Atacama Large Millimeter/submillimeter Array.

  17. Synchrotron self-inverse Compton radiation from reverse shock on GRB 120326A

    International Nuclear Information System (INIS)

    Urata, Yuji; Huang, Kuiyun; Takahashi, Satoko; Im, Myungshin; Kim, Jae-Woo; Jang, Minsung; Yamaoka, Kazutaka; Tashiro, Makoto; Pak, Soojong

    2014-01-01

    We present multi-wavelength observations of a typical long duration GRB 120326A at z = 1.798, including rapid observations using a Submillimeter Array (SMA) and a comprehensive monitoring in the X-ray and optical. The SMA observation provided the fastest detection to date among seven submillimeter afterglows at 230 GHz. The prompt spectral analysis, using Swift and Suzaku, yielded a spectral peak energy of E peak src =107.8 −15.3 +15.3 keV and an equivalent isotropic energy of E iso as 3.18 −0.32 +0.40 ×10 52 erg. The temporal evolution and spectral properties in the optical were consistent with the standard forward shock synchrotron with jet collimation (6.°69 ± 0.°16). The forward shock modeling, using a two-dimensional relativistic hydrodynamic jet simulation, was also determined by the reasonable burst explosion and the synchrotron radiation parameters for the optical afterglow. The X-ray light curve showed no apparent jet break and the temporal decay index relation between the X-ray and optical (αo – α X = –1.45 ± 0.10) indicated different radiation processes in each of them. Introducing synchrotron self-inverse Compton radiation from reverse shock is a possible solution, and the detection and slow decay of the afterglow in submillimeter supports that this is a plausible idea. The observed temporal evolution and spectral properties, as well as forward shock modeling parameters, enabled us to determine reasonable functions to describe the afterglow properties. Because half of the events share similar properties in the X-ray and optical as the current event, GRB 120326A will be a benchmark with further rapid follow-ups, using submillimeter instruments such as an SMA and the Atacama Large Millimeter/submillimeter Array.

  18. Sol–gel synthesis of long-lasting phosphors CdSiO3: Mn2+, RE3+ (RE = Tb, Eu, Nd) and luminescence mechanism research

    International Nuclear Information System (INIS)

    Qu, Xiaofei; Cao, Lixin; Liu, Wei; Su, Ge; Wang, Pingping; Schultz, Isabel

    2012-01-01

    Highlights: ► New long-lasting CdSiO 3 : Mn 2+ , RE 3+ (RE = Tb, Eu, Nd) phosphors were synthesized by a sol–gel method. ► The afterglow performance of the CdSiO 3 : Mn 2+ , Eu 3+ phosphor was the best. ► The role of RE 3+ co-doped into the CdSiO 3 : Mn 2+ matrix was discussed in this paper. -- Abstract: Mn 2+ and RE 3+ (RE = Tb, Eu, Nd) co-doped CdSiO 3 orange phosphors were prepared at 1050 °C by a sol–gel method. The phase and crystallinity of the synthesized materials were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The luminescence characteristics were analyzed using photoluminescence (PL) spectra, afterglow decay curves, long-lasting phosphorescence spectra, and thermoluminescence (TL) spectra. Due to the difference in co-doped rare earth ionic radii, it varied greatly in trap density and trap depth caused by the different defects deriving from RE 3+ ions co-doping into the CdSiO 3 : Mn 2+ host. The afterglow intensity and time for these samples increased as follows: CdSiO 3 : Mn 2+ 0.2%, Nd 3+ 0.8% 3 : Mn 2+ 0.4%, Tb 3+ 0.8% 3 : Mn 2+ 0.4%, Eu 3+ 0.3%. CdSiO 3 : Mn 2+ 0.4%, Eu 3+ 0.3% had the best afterglow properties, which could be due to the proper traps formed by Eu 3+ ions co-doping into the host. The role of RE 3+ co-doped into the CdSiO 3 : Mn 2+ matrix and the possible long-lasting phosphorescence process was also discussed in this paper.

  19. A MATURE DUSTY STAR-FORMING GALAXY HOSTING GRB 080607 AT z = 3.036

    International Nuclear Information System (INIS)

    Chen, Hsiao-Wen; Perley, Daniel A.; Cenko, S. Bradley; Bloom, Joshua S.; Wilson, Christine D.; Levan, Andrew J.; Prochaska, Jason X.; Tanvir, Nial R.; Dessauges-Zavadsky, Miroslava; Pettini, Max

    2010-01-01

    We report the discovery of the host galaxy of Swift dark burst GRB 080607 at z GRB = 3.036. GRB 080607 is a unique case of a highly extinguished (A V ∼ 3 mag) afterglow that was yet sufficiently bright for high-quality absorption-line spectroscopy. The host galaxy is clearly resolved in deep Hubble Space Telescope (HST) WF3/IR F160W images and well detected in the Spitzer IRAC 3.5 μm and 4.5 μm channels, while displaying little/no fluxes in deep optical images from Keck and Magellan. The extremely red optical-infrared colors are consistent with the large extinction seen in the afterglow light, suggesting that the large amount of dust and gas surface mass density seen along the afterglow sight line is not merely local but likely reflects the global dust content across the entire host galaxy. Adopting the dust properties and metallicity of the host interstellar medium derived from studies of early-time afterglow light and absorption-line spectroscopy, we perform a stellar population synthesis analysis of the observed spectral energy distribution to constrain the intrinsic luminosity and stellar population of this dark burst host. The host galaxy is best described by an exponentially declining star formation rate of e-folding time τ = 2 Gyr and an age of ∼2 Gyr. We also derive an extinction-corrected star formation rate of SFR ∼ 125 h -2 M sun yr -1 and a total stellar mass of M * ∼ 4 x 10 11 h -2 M sun . Our study provides an example of massive, dusty star-forming galaxies contributing to the γ-ray burst (GRB) host galaxy population, supporting the notion that long-duration GRBs trace the bulk of cosmic star formation.

  20. Laboratory constraints on chameleon dark energy and power-law fields

    OpenAIRE

    Steffen, Jason H.; Upadhye, Amol; Baumbaugh, Al; Chou, Aaron S.; Mazur, Peter O.; Tomlin, Ray; Weltman, Amanda; Wester, William

    2010-01-01

    We report results from the GammeV Chameleon Afterglow Search---a search for chameleon particles created via photon/chameleon oscillations within a magnetic field. This experiment is sensitive to a wide class of chameleon power-law models and dark energy models not previously explored. These results exclude five orders of magnitude in the coupling of chameleons to photons covering a range of four orders of magnitude in chameleon effective mass and, for individual chameleon models, exclude betw...

  1. The latest two GRB detected by Hete-2: GRB 051022 and GRB 051028

    International Nuclear Information System (INIS)

    Castro-Tirado, A. J.; Jelinek, M.; Pandey, S. B.; Ugarte Postigo, A. de; Gorosabel, J.; McBreen, S.; Bremer, M.; Guziy, S.; Bihain, G.; Caballero, J. A.; Ferrero, P.; Jong, J de; Misra, K.; Sahu, D. K.

    2006-01-01

    We present multiwavelength observations of the latest two GRB detected by Hete-2 in 2005. For GRB 051022, no optical/nIR afterglow has been detected, in spite of the strong gamma-ray emission and the reported X-ray afterglow discovered by Swift. A mm afterglow was discovered at PdB confirming the association of this event with a luminous (MV = - 21.5) galaxy within the X-ray error box. Spectroscopy of this galaxy shows strong a strong [O II] emission line at z = 0.807, besides weaker [O III] emission. The X-ray spectrum showed evidence of considerable absorption by neutral gas with NH,X-ray = 4.5 x 1022 cm2 (at rest frame). ISM absorption by dust in the host galaxy at z = 0.807 cannot certainly account for the non-detection of the optical afterglow, unless the dust-to-gas ratio is quite different than that seen in our Galaxy. It is possible then that GRB 051022 was produced in an obscured, stellar forming region in its parent host galaxy.For GRB 051028, the data can be interpreted by collimated emission (a jet model with p = 2.4) moving in an homogeneous ISM and with a cooling frequency vc still above the X-rays at 0.5 days after the burst onset. GRB 051028 can be classified as a 'gray' or 'potentially dark' GRB. The Swift/XRT data are consistent with the interpretation that the reason for the optical dimness is not extra absorption in the host galaxy, but rather the GRB taking place at high-redshift

  2. Image construction

    International Nuclear Information System (INIS)

    1976-01-01

    An image processing system fitting in an X-ray television circuit for tomography is described. The profiles registered by the X-ray television circuit are projected on the screen of an afterglow cathode ray tube which registration is convoluted in an analogue system with the help of either a one-dimensional or a two-dimensional convolution function after which it is stored or processed further such that a clear tomogram is obtained

  3. Plasma Assisted Ignition and Combustion at Low Initial Gas Temperatures: Development of Kinetic Mechanism

    Science.gov (United States)

    2016-10-05

    voltage J. Phys. D: Appl. Phys. 36 2683 [25] Soloviev V, Krivtsov V 2009 SDBD discharge modelling for aerodynamic applications J. Phys. D: Appl. Phys...effects. Plasma Sources Sci. Technol. 18 034018 (13pp). [14] Soloviev V, Krivtsov V. 2009. Surface barrier discharge modelling for aerodynamic applications...Lempert W and Gundersen MA. 2012. Vi- brational and rotational CARS measurements of nitrogen in afterglow of streamer discharge in atmospheric

  4. Selected ion flow tube mass spectrometry for on-line trace gas analysis in biology and medicine

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Smith, D.

    2007-01-01

    Roč. 13, č. 1 (2007), s. 77-82 ISSN 1469-0667 R&D Projects: GA ČR GA202/06/0776 Institutional research plan: CEZ:AV0Z40400503 Keywords : selected ion flow tube mass spectroscopy (SIFT-MS) * breath analysis * breath metabolities * flowing afterglow mass spectrometry (FA-MS) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.198, year: 2007

  5. Recombination of cluster ions

    Science.gov (United States)

    Johnsen, Rainer

    1993-01-01

    Some of our recent work on molecular band emissions from recombination of molecular dimer ions (N4(+) and CO(+) CO) is discussed. Much of the experimental work was done by Y. S. Cao; the results on N4(+) recombination have been published. A brief progress report is given on our ongoing measurements of neutral products of recombination using the flowing-afterglow Langmuir-probe technique in conjunction with laser-induced fluorescence.

  6. An Artificial Intelligence Classification Tool and Its Application to Gamma-Ray Bursts

    Science.gov (United States)

    Hakkila, Jon; Haglin, David J.; Roiger, Richard J.; Giblin, Timothy; Paciesas, William S.; Pendleton, Geoffrey N.; Mallozzi, Robert S.

    2004-01-01

    Despite being the most energetic phenomenon in the known universe, the astrophysics of gamma-ray bursts (GRBs) has still proven difficult to understand. It has only been within the past five years that the GRB distance scale has been firmly established, on the basis of a few dozen bursts with x-ray, optical, and radio afterglows. The afterglows indicate source redshifts of z=1 to z=5, total energy outputs of roughly 10(exp 52) ergs, and energy confined to the far x-ray to near gamma-ray regime of the electromagnetic spectrum. The multi-wavelength afterglow observations have thus far provided more insight on the nature of the GRB mechanism than the GRB observations; far more papers have been written about the few observed gamma-ray burst afterglows in the past few years than about the thousands of detected gamma-ray bursts. One reason the GRB central engine is still so poorly understood is that GRBs have complex, overlapping characteristics that do not appear to be produced by one homogeneous process. At least two subclasses have been found on the basis of duration, spectral hardness, and fluence (time integrated flux); Class 1 bursts are softer, longer, and brighter than Class 2 bursts (with two second durations indicating a rough division). A third GRB subclass, overlapping the other two, has been identified using statistical clustering techniques; Class 3 bursts are intermediate between Class 1 and Class 2 bursts in brightness and duration, but are softer than Class 1 bursts. We are developing a tool to aid scientists in the study of GRB properties. In the process of developing this tool, we are building a large gamma-ray burst classification database. We are also scientifically analyzing some GRB data as we develop the tool. Tool development thus proceeds in tandem with the dataset for which it is being designed. The tool invokes a modified KDD (Knowledge Discovery in Databases) process, which is described as follows.

  7. Thermoluminescent phosphors for ultraviolet radiation dosimetry - a review

    International Nuclear Information System (INIS)

    Nagpal, J.S.

    2001-01-01

    Intrinsic TL response of CaSO 4 , CaF 2 , Al 2 O 3 (Si,Ti), Mg 2 SiO 4 : Tb and lamp phosphors to ultraviolet radiation is reviewed. Taking into consideration the characteristics such as afterglow at RT, rate/flux dependence, linearity of response, useful range, spectral dependence and effect of sequential/tandem UV exposures CaF 2 :Eu 2+ is an ideal TL dosemeter for UV radiation dosimetry. (author)

  8. Experiments on Ion-Ion Plasmas From Discharges

    Science.gov (United States)

    Leonhardt, Darrin; Walton, Scott; Blackwell, David; Murphy, Donald; Fernsler, Richard; Meger, Robert

    2001-10-01

    Use of both positive and negative ions in plasma processing of materials has been shown to be advantageous[1] in terms of better feature evolution and control. In this presentation, experimental results are given to complement recent theoretical work[2] at NRL on the formation and decay of pulsed ion-ion plasmas in electron beam generated discharges. Temporally resolved Langmuir probe and mass spectrometry are used to investigate electron beam generated discharges during the beam on (active) and off (afterglow) phases in a variety of gas mixtures. Because electron-beam generated discharges inherently[3] have low electron temperatures (<0.5eV in molecular gases), negative ion characteristics are seen in the active as well as afterglow phases since electron detachment increases with low electron temperatures. Analysis of temporally resolved plasma characteristics deduced from these measurements will be presented for pure O_2, N2 and Ar and their mixtures with SF_6. Oxygen discharges show no noticeable negative ion contribution during the active or afterglow phase, presumably due to the higher energy electron attachment threshold, which is well above any electron temperature. In contrast, SF6 discharges demonstrate ion-ion plasma characteristics in the active glow and are completely ion-ion in the afterglow. Comparison between these discharges with published cross sections and production mechanisms will also be presented. [1] T.H. Ahn, K. Nakamura & H. Sugai, Plasma Sources Sci. Technol., 5, 139 (1996); T. Shibyama, H. Shindo & Y. Horiike, Plasma Sources Sci. Technol., 5, 254 (1996). [2] See presentation by R. F. Fernsler, at this conference. [3] D. Leonhardt, et al., 53rd Annual GEC, Houston, TX.

  9. Optical emissions from the dissociative recombination of N{sub 2}H{sup +}, HCO{sup +}, HOC{sup +}, and HNC{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, R [Department of Physics and Astronomy University of Pittsburgh, Pittsburgh, PA 15260 (United States); Golde, M F [Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Rosati, R E [Smithsonian Astrophysical Observatory, 60 Garden St. MS-50 Cambridge, MA, 02138 (United States); Pappas, D [Army Research Laboratory, 4600 Deer Creek Loop, Aberdeen Proving Ground, MD (United States); Skrzypkowski, M P, E-mail: rj@pitt.ed [Prometheus Energy Company, 3311 S. 120th Place Suite 100, Seattle, WA 98168 (United States)

    2009-11-15

    We present recent flowing-afterglow measurements of branching fractions for electronically and vibrationally excited products arising from the dissociative recombination of N{sub 2}H{sup +}, HCO{sup +}, HOC{sup +}, and HNC{sup +} ions with thermal electrons. State-specific yields were derived by fitting the observed, spatially resolved emission band intensities to models that simulate all ion-chemical processes, recombination, diffusion, and gas mixing.

  10. Force-free electromagnetic pulses in a laboratory plasma

    Science.gov (United States)

    Stenzel, R. L.; Urrutia, J. M.

    1990-01-01

    A short, intense current pulse is drawn from an electrode immersed in a magnetized afterglow plasma. The induced magnetic field B(r,t) assumes the shape of a helical double vortex which propagates along B(0) through the uniform plasma as a whistler mode. The observations support a prediction of force-free (J x B + neE = 0) electromagnetic fields and solitary waves. Energy and helicity are approximately conserved.

  11. A Decade of GRB Follow-Up by BOOTES in Spain (2003–2013

    Directory of Open Access Journals (Sweden)

    Martin Jelínek

    2016-01-01

    Full Text Available This article covers ten years of GRB follow-ups by the Spanish BOOTES stations: 71 follow-ups providing 23 detections. Follow-ups by BOOTES-1B from 2005 to 2008 were given in a previous article and are here reviewed and updated, and additional detection data points are included as the former article merely stated their existence. The all-sky cameras CASSANDRA have not yet detected any GRB optical afterglows, but limits are reported where available.

  12. GRB 120521C at z ∼ 6 and the properties of high-redshift γ-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Laskar, Tanmoy; Berger, Edo; Zauderer, B. Ashley; Margutti, Raffaella; Fong, Wen-fai [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tanvir, Nial; Wiersema, Klaas [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Levan, Andrew [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Perley, Daniel [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Menten, Karl [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Hrudkova, Marie [Isaac Newton Group of Telescopes, Apartado de Correos 321, E-387 00 Santa Cruz de la Palma, Canary Islands (Spain)

    2014-01-20

    We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength data set, we derive a photometric redshift of z ≈ 6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of n ≲ 0.05 cm{sup –3}. The radio observations reveal the presence of a jet break at t {sub jet} ≈ 7 d, corresponding to a jet opening angle of θ{sub jet} ≈ 3°. The beaming-corrected γ-ray and kinetic energies are E {sub γ} ≈ E{sub K} ≈ 3 × 10{sup 50} erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z ≳ 6 with radio detections (GRBs 050904 and 090423). We find a jet break at t {sub jet} ≈ 15 d for GRB 090423, in contrast to previous work. Based on these three events, we find that γ-ray bursts (GRBs) at z ≳ 6 appear to explode in constant-density environments, and exhibit a wide range of energies and densities that span the range inferred for lower redshift bursts. On the other hand, we find a hint for narrower jets in the z ≳ 6 bursts, potentially indicating a larger true event rate at these redshifts. Overall, our results indicate that long GRBs share a common progenitor population at least to z ∼ 8.

  13. A Case Study of On-the-fly Wide-field Radio Imaging Applied to the Gravitational Wave Event GW151226

    Science.gov (United States)

    Mooley, K. P.; Frail, D. A.; Myers, S. T.; Kulkarni, S. R.; Hotokezaka, K.; Singer, L. P.; Horesh, A.; Kasliwal, M. M.; Cenko, S. B.; Hallinan, G.

    2018-04-01

    We apply a newly developed on-the-fly mosaicing technique on the Jansky Very Large Array (VLA) at 3 GHz in order to carry out a sensitive search for an afterglow from the Advanced LIGO binary black hole merger event GW151226. In three epochs between 1.5 and 6 months post-merger, we observed a 100 deg2 region, with more than 80% of the survey region having an rms sensitivity of better than 150 μJy/beam, in the northern hemisphere with a merger containment probability of 10%. The data were processed in near real time and analyzed to search for transients and variables. No transients were found but we have demonstrated the ability to conduct blind searches in a time-frequency phase space where the predicted afterglow signals are strongest. If the gravitational wave event is contained within our survey region, the upper limit on any late-time radio afterglow from the merger event at an assumed mean distance of 440 Mpc is about 1029 erg s‑1 Hz‑1. Approximately 1.5% of the radio sources in the field showed variability at a level of 30%, and can be attributed to normal activity from active galactic nuclei. The low rate of false positives in the radio sky suggests that wide-field imaging searches at a few Gigahertz can be an efficient and competitive search strategy. We discuss our search method in the context of the recent afterglow detection from GW170817 and radio follow-up in future gravitational wave observing runs.

  14. Space-Charge Effects in a Gas Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D.D.

    2010-12-03

    Discussion of space-charge effects in a photoluminescence cell that will be used as a nondisruptive total energy monitor at the LCLS facility is presented. Regimes where primary photoelectrons will be confined within the X-ray beam aperture are identified. Effects of the space-charge on the further evolution of the electron and ion populations are discussed. Parameters of the afterglow plasma are evaluated. Conditions under which the detector output will be proportional to the pulse energy are defined.

  15. Temperature Dependences for the Reactions of Ar+, O2+, and C7H7+ with Toluene and Ethylbenzene

    Science.gov (United States)

    2013-07-01

    Pi-Pi-Interactions; Flowing Afterglow; Charge-Transfer; Gas -Phase; Electronic-Structure; Mass-Spectrometry; Gaseous Benzene; Tropylium Ion; Cations...filter and the desired mass ion was selected. he ions enter the flow tube through a Venturi inlet and are car- ied downstreamby a heliumbuffer. After...9 cm of the flow tube, and subsequently the flow was sampled hrough a small orifice in a rounded nose cone. The remainder of he flow was pumped away

  16. Gamma-ray bursts - a critical review

    International Nuclear Information System (INIS)

    Tudose, Valeriu; Biermann, Peter

    2003-01-01

    We present a short general introduction into the field of gamma-ray bursts (GRBs) research, summarizing the past and the present status. We give an general view of the GRBs observations to date, both in the prompt emission phase as well as in the afterglow phase, and a brief primer into the theory, mainly in the frame-work of the fireball model. (authors)

  17. XRED

    DEFF Research Database (Denmark)

    Krumpe, Mirko; Coffey, Deirdre; Egger, Georg

    2005-01-01

    to detect high redshift gamma-rays, an x-ray focussing telescope to determine accurate coordinates and extract spectra, and an infrared spectrograph to observe the high redshift optical afterglow. The mission is expected to detect and identify for the first time GRBs with z > 10, thereby providing...... constraints on properties of the first generation of stars and the history of the early Universe....

  18. The Futility of Force and the Preservation of Power: British Strategic Failure in America, 1780-83

    Science.gov (United States)

    2012-01-01

    afterglow of decisive victory in the Seven Years War, presided over a vast and unprecedented global empire. The small island nation seemingly, and rather...the American militia.10 Second, most, if not all, of these same men , severely misjudged the extent and veracity of popular support the patriot...the government’s planning and conduct of the war and unleashed a torrent of political blame and recrimination that very nearly toppled the North

  19. Understanding British Strategic Failure in America: 1780-1783

    Science.gov (United States)

    2012-03-17

    basking in the warm afterglow of decisive victory in the Seven Years War, presided over a vast and unprecedented global Empire. The small island nation...prowess of the American militia.11 Second, most, if not all, of these same men , severely misjudged the extent and veracity of popular support the...conduct of the war and unleashed a torrent of political blame and recrimination that very nearly toppled the North Ministry.25 The government’s

  20. Method for producing metallic nanoparticles

    Science.gov (United States)

    Phillips, Jonathan; Perry, William L.; Kroenke, William J.

    2004-02-10

    Method for producing metallic nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating non-oxidizing plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone to metal vapor. The metal vapor is directed away from the hot zone and to the plasma afterglow where it cools and condenses to form solid metallic nanoparticles.

  1. Method for producing metallic microparticles

    Science.gov (United States)

    Phillips, Jonathan; Perry, William L.; Kroenke, William J.

    2004-06-29

    Method for producing metallic particles. The method converts metallic nanoparticles into larger, spherical metallic particles. An aerosol of solid metallic nanoparticles and a non-oxidizing plasma having a portion sufficiently hot to melt the nanoparticles are generated. The aerosol is directed into the plasma where the metallic nanoparticles melt, collide, join, and spheroidize. The molten spherical metallic particles are directed away from the plasma and enter the afterglow where they cool and solidify.

  2. VizieR Online Data Catalog: Polarimetry & photometry of GRB with RINGO2 (Steele+, 2017)

    Science.gov (United States)

    Steele, I. A.; Kopac, D.; Arnold, D. M.; Smith, R. J.; Kobayashi, S.; Jermak, H. E.; Mundell, C. G.; Gomboc, A.; Guidorzi, C.; Melandri, A.; Japelj, J.

    2018-03-01

    Between 2010 and 2012, 19 optical afterglows were observed with the RINGO2 polarimeter on the Liverpool Telescope (LT) at La Palma. Table 2 shows observational properties of the complete sample. In addition to the RINGO2 observations, optical band photometry of each burst was carried out using the RATCam CCD imaging camera on the same telescope, using either g'r'i' or r'i'z' filter sequences, in intervals between and after the RINGO2 observations. (3 data files).

  3. Influence of Mo impurity on the spectroscopic and scintillation properties of PbWO4 crystals

    International Nuclear Information System (INIS)

    Boehm, M.; Hofstaetter, A.; Luh, M.; Meyer, B.K.; Scharmann, A.; Drobychev, G.Yu.; Grenoble-1 Univ., 74 - Annecy; Peigneux, J.P.

    1997-12-01

    The influence of molybdenum doping on the spectroscopic and scintillation properties of lead tungstate crystals has been investigated. From the results the slow scintillation component as well as the afterglow are found to be due to the Mo impurity. In addition the blue luminescence from excited (WO 4 ) 2- -complex seems to be increasingly suppressed as the doping concentration goes on. Possible mechanisms for the effects have been discussed. (author)

  4. High energy particles from {gamma}-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Waxman, E [Weizmann Institute of Science, Rehovot (Israel)

    2001-11-15

    A review is presented of the fireball model of {gamma}-ray bursts (GRBs), and of the production in GRB fireballs of high energy protons and neutrinos. Constraints imposed on the model by recent afterglow observations, which support the association of GRB and ultra-high energy cosmic-ray (UHECR) sources, are discussed. Predictions of the GRB model for UHECR production, which can be tested with planned large area UHECR detectors and with planned high energy neutrino telescopes, are reviewed. (author)

  5. Optimization of decay kinetics of YAG:Ce single crystal scintillators for S(T)EM electron detectors

    Czech Academy of Sciences Publication Activity Database

    Schauer, Petr

    2011-01-01

    Roč. 269, č. 21 (2011), s. 2572-2577 ISSN 0168-583X R&D Projects: GA ČR GAP102/10/1410 Institutional research plan: CEZ:AV0Z20650511 Keywords : scintillation detector * electron microscope * cathodoluminescence * YAG:Ce single crystal scintillator * decay time * afterglow * kinetic model * SEM * STEM Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.211, year: 2011

  6. Composition and properties tailoring in Mg.sup.2+./sup. codoped non-stoichiometric LuAG:Ce,Mg scintillation ceramics

    Czech Academy of Sciences Publication Activity Database

    Liu, S.; Mareš, Jiří A.; Babin, Vladimir; Hu, C.; Kou, H.; D'Ambrosio, C.; Li, J.; Pan, Y.; Nikl, Martin

    2017-01-01

    Roč. 37, č. 4 (2017), s. 1689-1694 ISSN 0955-2219 R&D Projects: GA ČR GA16-15569S Institutional support: RVO:68378271 Keywords : non-stoichiometric ceramic s * LuAG:Ce * Mg scintillator * Mg 2+ codopant * antisite defects * afterglow Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.411, year: 2016

  7. Discovery of the short gamma-ray burst GRB 050709.

    Science.gov (United States)

    Villasenor, J S; Lamb, D Q; Ricker, G R; Atteia, J-L; Kawai, N; Butler, N; Nakagawa, Y; Jernigan, J G; Boer, M; Crew, G B; Donaghy, T Q; Doty, J; Fenimore, E E; Galassi, M; Graziani, C; Hurley, K; Levine, A; Martel, F; Matsuoka, M; Olive, J-F; Prigozhin, G; Sakamoto, T; Shirasaki, Y; Suzuki, M; Tamagawa, T; Vanderspek, R; Woosley, S E; Yoshida, A; Braga, J; Manchanda, R; Pizzichini, G; Takagishi, K; Yamauchi, M

    2005-10-06

    Gamma-ray bursts (GRBs) fall into two classes: short-hard and long-soft bursts. The latter are now known to have X-ray and optical afterglows, to occur at cosmological distances in star-forming galaxies, and to be associated with the explosion of massive stars. In contrast, the distance scale, the energy scale and the progenitors of the short bursts have remained a mystery. Here we report the discovery of a short-hard burst whose accurate localization has led to follow-up observations that have identified the X-ray afterglow and (for the first time) the optical afterglow of a short-hard burst; this in turn led to the identification of the host galaxy of the burst as a late-type galaxy at z = 0.16 (ref. 10). These results show that at least some short-hard bursts occur at cosmological distances in the outskirts of galaxies, and are likely to be caused by the merging of compact binaries.

  8. Observations of short gamma-ray bursts.

    Science.gov (United States)

    Fox, Derek B; Roming, Peter W A

    2007-05-15

    We review recent observations of short-hard gamma-ray bursts and their afterglows. The launch and successful ongoing operations of the Swift satellite, along with several localizations from the High-Energy Transient Explorer mission, have provoked a revolution in short-burst studies: first, by quickly providing high-quality positions to observers; and second, via rapid and sustained observations from the Swift satellite itself. We make a complete accounting of Swift-era short-burst localizations and proposed host galaxies, and discuss the implications of these observations for the distances, energetics and environments of short bursts, and the nature of their progenitors. We then review the physical modelling of short-burst afterglows: while the simplest afterglow models are inadequate to explain the observations, there have been several notable successes. Finally, we address the case of an unusual burst that threatens to upset the simple picture in which long bursts are due to the deaths of massive stars, and short bursts to compact-object merger events.

  9. A cannonball model of gamma-ray bursts superluminal signatures

    CERN Document Server

    Dar, Arnon; Dar, Arnon; Rujula, Alvaro De

    2000-01-01

    Recent observations suggest that the long-duration gamma ray bursts (GRBs) and their afterglows are produced by highly relativistic jets emitted in supernova explosions. We propose that the result of the event is not just a compact object plus the ejecta: within a day, a fraction of the parent star falls back to produce a thick accretion disk. The subsequent accretion generates jets and constitutes the GRB ``engine'', as in the observed ejection of relativistic ``cannonballs'' of plasma by microquasars and active galactic nuclei. The GRB is produced as the jetted cannonballs exit the supernova shell reheated by the collision, re-emitting their own radiation and boosting the light of the shell. They decelerate by sweeping up interstellar matter, which is accelerated to cosmic-ray energies and emits synchrotron radiation: the afterglow. We emphasize here a smoking-gun signature of this model of GRBs: the superluminal motion of the afterglow, that can be searched for ---the sooner the better--- in the particular...

  10. GRB 071112C: A CASE STUDY OF DIFFERENT MECHANISMS IN X-RAY AND OPTICAL TEMPORAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Huang, K. Y.; Tung, Y. H.; Lin, H. M.; Wang, S. Y.; Lehner, M. J.; Wang, J. H.; Wen, C. Y. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Urata, Y.; Ip, W. H. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Xin, L. P.; Qiu, Y.; Wei, J. [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Yoshida, M. [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Zheng, W.; Akerlof, C. [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Bianco, F. B. [Department of Physics, University of California Santa Barbara, Mail Code 9530, Santa Barbara, CA 93106-9530 (United States); Kawai, N. [Department of Physics, Tokyo Institute of Technology, 2-21-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Kuroda, D. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Asakuchi, Okayama 719-0232 (Japan); Marshall, S. L. [Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, MS 29, Menlo Park, CA 94025 (United States); Schwamb, M. E. [Department of Physics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); and others

    2012-03-20

    We present a study on GRB 071112C X-ray and optical light curves. In these two wavelength ranges, we have found different temporal properties. The R-band light curve showed an initial rise followed by a single power-law decay, while the X-ray light curve was described by a single power-law decay plus a flare-like feature. Our analysis shows that the observed temporal evolution cannot be described by the external shock model in which the X-ray and optical emission are produced by the same emission mechanism. No significant color changes in multi-band light curves and a reasonable value of the initial Lorentz factor ({Gamma}{sub 0} = 275 {+-} 20) in a uniform interstellar medium support the afterglow onset scenario as the correct interpretation for the early R band rise. The result suggests that the optical flux is dominated by afterglow. Our further investigations show that the X-ray flux could be created by an additional feature related to energy injection and X-ray afterglow. Different theoretical interpretations indicate the additional feature in X-ray can be explained by either late internal dissipation or local inverse-Compton scattering in the external shock.

  11. ENERGETIC FERMI/LAT GRB 100414A: ENERGETIC AND CORRELATIONS

    International Nuclear Information System (INIS)

    Urata, Yuji; Tsai, Patrick P.; Huang, Kuiyun; Yamaoka, Kazutaka; Tashiro, Makoto S.

    2012-01-01

    This study presents multi-wavelength observational results for energetic GRB 100414A with GeV photons. The prompt spectral fitting using Suzaku/WAM data yielded spectral peak energies of E src peak of 1458.7 +132.6 –106.6 keV and E iso of 34.5 +2.0 –1.8 × 10 52 erg with z = 1.368. The optical afterglow light curves between 3 and 7 days were effectively fitted according to a simple power law with a temporal index of α = –2.6 ± 0.1. The joint light curve with earlier Swift/UVOT observations yields a temporal break at 2.3 ± 0.2 days. This was the first Fermi/LAT detected event that demonstrated the clear temporal break in the optical afterglow. The jet opening angle derived from this temporal break was 5. 0 8, consistent with those of other well-observed long gamma-ray bursts (GRBs). The multi-wavelength analyses in this study showed that GRB 100414A follows E src peak -E iso and E src peak -E γ correlations. The late afterglow revealed a flatter evolution with significant excesses at 27.2 days. The most straightforward explanation for the excess is that GRB 100414A was accompanied by a contemporaneous supernova. The model light curve based on other GRB-SN events is marginally consistent with that of the observed light curve.

  12. Modelling of time delay of electrical breakdown for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar in the increase region of the memory curve

    International Nuclear Information System (INIS)

    Nesic, N T; Ristic, G S; Pejovic, M M; Karamarkovic, J P

    2008-01-01

    Experimentally measured electrical breakdown time delay data versus the afterglow period (representing 'memory curves') for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar have been shown. The influence of N( 4 S) nitrogen atoms on secondary electron emission from the cathode (the SEE process) in late afterglow has been discussed. N( 4 S) atom concentration decay over relaxation time τ, N( 4 S)(τ), has been analysed by a numerical model and two analytical models. N( 4 S) decay analytical models are combined with different yield models that describe the SEE process by N( 4 S) and these combinations are employed to fit the experimental data. It has been shown that in late afterglow solving of very simple analytical equations instead of numerical solving of partial differential equations for N( 4 S)(τ) fitting can be used and that the combination of the first and the second order of the SEE process by N( 4 S) in yield modelling should be used in the case of 13.3 mbar pressure.

  13. Gamma-ray Burst X-ray Flares Light Curve Fitting

    Science.gov (United States)

    Aubain, Jonisha

    2018-01-01

    Gamma Ray Bursts (GRBs) are the most luminous explosions in the Universe. These electromagnetic explosions produce jets demonstrated by a short burst of prompt gamma-ray emission followed by a broadband afterglow. There are sharp increases of flux in the X-ray light curves known as flares that occurs in about 50% of the afterglows. In this study, we characterized all of the X-ray afterglows that were detected by the Swift X-ray Telescope (XRT), whether with flares or without. We fit flares to the Norris function (Norris et al. 2005) and power laws with breaks where necessary (Racusin et al. 2009). After fitting the Norris function and power laws, we search for the residual pattern detected in prompt GRB pulses (Hakkila et al. 2014, 2015, 2017), that may indicate a common signature of shock physics. If we find the same signature in flares and prompt pulses, it provides insight into what causes them, as well as, how these flares are produced.

  14. CONSTRAINTS ON OBSCURED STAR FORMATION IN HOST GALAXIES OF GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Hatsukade, Bunyo; Ohta, Kouji; Hashimoto, Tetsuya; Nakanishi, Kouichiro; Tamura, Yoichi; Kohno, Kotaro

    2012-01-01

    We present the results of the 16 cm wave band continuum observations of four host galaxies of gamma-ray bursts (GRBs) 990705, 021211, 041006, and 051022 using the Australia Telescope Compact Array. Radio emission was not detected in any of the host galaxies. The 2σ upper limits on star formation rates derived from the radio observations of the host galaxies are 23, 45, 27, and 26 M ☉ yr –1 , respectively, which are less than about 10 times those derived from UV/optical observations, suggesting that they have no significant dust-obscured star formation. GRBs 021211 and 051022 are known as the so-called dark GRBs and our results imply that dark GRBs do not always occur in galaxies enshrouded by dust. Because large dust extinction was not observed in the afterglow of GRB 021211, our result suggests the possibility that the cause of the dark GRB is the intrinsic faintness of the optical afterglow. On the other hand, by considering the high column density observed in the afterglow of GRB 051022, the likely cause of the dark GRB is the dust extinction in the line of sight of the GRB.

  15. A Fe K Line in GRB 970508

    Science.gov (United States)

    Protassov, R.; van Dyk, D.; Connors, A.; Kashyap, V.; Siemiginowska, A.

    2000-12-01

    We examine the x-ray spectrum of the afterglow of GRB 970508, analyzed for Fe line emission by Piro et al (1999, ApJL, 514, L73). This is a difficult and extremely important measurement: the detection of x-ray afterglows from γ -ray bursts is at best a tricky business, relying on near-real satellite time response to unpredictable events; and a great deal of luck in catching a burst bright enough for a useful spectral analysis. Detecting a clear atomic (or cyclotron) line in the generally smooth and featureless afterglow (or burst) emission not only gives one of the few very specific keys to the physics local to the emission region, but also provides clues or confirmation of its distance (via redshift). Unfortunately, neither the likelihood ratio test or the related F-statistic commonly used to detect spectral lines adhere to their nominal Chi square and F-distributions. Thus we begin by calibrating the F-statistic used in Piro et al (1999, ApJL, 514, L73) via a simulation study. The simulation study relies on a completely specified source model, i.e. we do Monte Carlo simulations with all model parameters fixed (so--called ``parametric bootstrapping''). Second, we employ the method of posterior predictive p-values to calibrate a LRT statistic while accounting for the uncertainty in the parameters of the source model. Our analysis reveals evidence for the Fe K line.

  16. Unveiling the Progenitors of Short-duration Gamma-ray Bursts

    Science.gov (United States)

    Fong, Wen-Fai

    2016-03-01

    Gamma-ray bursts (GRBs) are relativistic explosions which originate at cosmological distances, and are among the most luminous transients in the universe. Following the prompt gamma-ray emission, a fading synchrotron ``afterglow'' is detectable at lower energies. While long-duration GRBs (duration >2 sec) are linked to the deaths of massive stars, the progenitors of short-duration GRBs (duration black hole. Such merging systems are also important to understand because they are premier candidates for gravitational wave detections with current facilities and are likely sites of heavy element nucleosynthesis. The launch of NASA's Swift satellite in 2004, with its rapid multi-wavelength monitoring and localization capabilities, led to the first discoveries of short GRB afterglows and therefore robust associations to host galaxies. At a detection rate of roughly 10 events per year, the growing number of well-localized short GRBs has enabled comprehensive population studies of their afterglows and environments for the first time. In this talk, I describe my multi-wavelength observational campaign to address testable predictions for the progenitors of short GRBs. My work comprises several lines of independent evidence to demonstrate that short GRBs originate from the mergers of two compact objects, and also provides the first constraints on the explosion properties for a large sample of events. With the direct detection of gravitational waves from compact object mergers on the horizon, these studies provide necessary inputs to inform the next decade of joint electromagnetic-gravitational wave search strategies.

  17. Polarimetry and Photometry of Gamma-Ray Bursts with RINGO2

    Science.gov (United States)

    Steele, I. A.; Kopač, D.; Arnold, D. M.; Smith, R. J.; Kobayashi, S.; Jermak, H. E.; Mundell, C. G.; Gomboc, A.; Guidorzi, C.; Melandri, A.; Japelj, J.

    2017-07-01

    We present a catalog of early-time (˜ {10}2-{10}4 s) photometry and polarimetry of all gamma-ray burst (GRB) optical afterglows observed with the RINGO2 imaging polarimeter on the Liverpool Telescope. Of the 19 optical afterglows observed, the following nine were bright enough to perform photometry and attempt polarimetry: GRB 100805A, GRB 101112A, GRB 110205A, GRB 110726A, GRB 120119A, GRB 120308A, GRB 120311A, GRB 120326A, and GRB 120327A. We present multiwavelength light curves for these 9 GRBs, together with estimates of their optical polarization degrees and/or limits. We carry out a thorough investigation of detection probabilities, instrumental properties, and systematics. Using two independent methods, we confirm previous reports of significant polarization in GRB 110205A and 120308A, and report the new detection of P={6}-2+3% in GRB101112A. We discuss the results for the sample in the context of the reverse- and forward-shock afterglow scenario, and show that GRBs with detectable optical polarization at early time have clearly identifiable signatures of reverse-shock emission in their optical light curves. This supports the idea that GRB ejecta contain large-scale magnetic fields, and it highlights the importance of rapid-response polarimetry.

  18. Modeling Gamma-Ray Bursts in the Swift-Fermi era

    International Nuclear Information System (INIS)

    Hascoet, Romain

    2012-01-01

    Gamma-Ray Bursts (GRBs) are short flashes (≅ 10 ms-100 s) of gamma-rays (keV-MeV). These very bright and variable events are followed by an afterglow detected from the X-ray to the optical and radio domains, which decays rapidly and vanishes in a few days/weeks. Their extreme luminosity make them detectable up to cosmological distances (at least to a redshift of 9). They are produced by relativistic jets launched by a newborn compact object. The gamma-ray emission is attributed to internal mechanisms occurring within the jet and the afterglow to the deceleration by the circum-burst medium. The Swift satellite launched in 2004 has improved our knowledge of the afterglow (especially the early phase), while the Fermi satellite launched in 2008 has opened a new spectral window at high energy (above 100 MeV). My research work is in line with these recent observational breakthroughs which challenge the 'standard' GRB model that was established in the 90's. I have developed numerical tools that are well adapted to model in a consistent way the different emission phases experienced by the relativistic jet, from the photosphere to the deceleration. Using these tools, I have obtained several results that contribute to a better understanding of GRB physics. Regarding the GRB itself, I developed a new approach to compute precisely the opacity seen by a high-energy photon that propagates within a ultra-relativistic jet. By comparing predictions to Fermi observations, I obtain critical constraints on the physical conditions in the relativistic jet (especially the Lorentz factor). I have also tried to identify observational signatures that could help to discriminate between different emission models: spectral (optical and high energy emission, thermal component) and temporal (transition to the afterglow) signatures. Regarding the afterglow, I have carried on the development of an alternative model - the 'reverse shock' model - recently proposed to explain the phenomenological

  19. Gamma-Ray Bursts: Lighting Up the High-Redshift Universe

    Science.gov (United States)

    Toy, Vicki Louise

    Gamma-ray bursts (GRBs) are the most luminous events in the Universe with Egamma,iso ˜ 1048-54 erg. Leading models hypothesize that GRBs are created from inter- nal collisions within collimated and ultrarelativistic jets. The jets then shock-heat the surrounding material (e.g. interstellar medium) to create GRB afterglows. These afterglows are extremely useful probes of the Universe because long GRBs are (1) bright events that can be used as backlights for absorption studies, (2) able to probe at all redshifts massive stars exist, and (3) transient events that allow us to follow- up on the host galaxies at late times. In this thesis we study the environments of GRBs. We first explore the relationship between GRB and supernova (SN) using a nearby GRB-SN (GRB 130702A/SN 2013dx) at z = 0.145. There are only nine other GRB-SNe that were close enough to have extensive spectroscopic and photometric follow-up of the SN at late times. We create a quasi-bolometic light curve of SN 2013dx and fit an analytical equation to the quasi-bolometric light curve combined with measurements of the photospheric velocity to determine SN parameters: mass of 56Ni, kinetic energy, and ejecta mass. We examine the relationship between SN parameters and E gamma,iso for the 10 well-studied GRB-SNe, but find no correlations despite numerical simulation predictions that the mass of 56Ni should correlate with the degree of asymmetry. We then move to larger distance scales and use GRB afterglows as bright back- lights to study distant galaxies. We examine the galactic environments of Damped Lyman-alpha systems (DLAs; NHI ≥ 1020.3 cm-2 ) identified with GRB afterglows at z ˜ 2 - 6. We use late-time photometry after the GRB afterglow has faded to determine star formation rates (SFRs) from rest-frame ultraviolet measurements or spectral energy distribution (SED) models from multiband photometry. We com- pare our sample's SFRs to a sample of quasars (QSOs) DLA host galaxies. Despite the

  20. What did we learn from gamma-ray burst 080319B?

    International Nuclear Information System (INIS)

    Panaitescu, Alin; Kumar, Pawan

    2008-01-01

    The optical and gamma-ray observations of GRB 080319B allow us to provide a broad-brush picture for this remarkable burst. The data indicate that the prompt optical and gamma-ray photons were possibly produced at the same location but by different radiation processes: synchrotron and synchrotron self-Compton, respectively (but we note that this interpretation of the gamma-ray data faces some difficulties). We find that the burst prompt optical emission was produced at a distance of 10 16.3 cm by an ultrarelativistic source moving at Lorentz factor of -500. A straightforward inference is that about 10 times more energy must have been radiated at tens of GeV than that released at 1 MeV. Assuming that the GRB outflow was baryonic and the gamma-ray source was shock-heated plasma, the collimation-corrected kinetic energy of the jet powering GRB 080319B was larger than 10 52.3 erg. The decay of the early afterglow optical emission (up to 1 ks) is too fast to be attributed to the reverse-shock crossing the GRB ejecta but is consistent with the expectations for the 'large-angle' emission released during the burst. The pure power-law decay of the optical afterglow flux from 1 ks to 10 d is most naturally identified with the (synchrotron) emission from the shock propagating into a wind-like medium. However, the X-ray afterglow requires a departure from the standard blast-wave model.

  1. ENERGETIC FERMI/LAT GRB 100414A: ENERGETIC AND CORRELATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Yuji; Tsai, Patrick P. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106, Taiwan (China); Yamaoka, Kazutaka [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1, Fuchinobe, Sayamihara 229-8558 (Japan); Tashiro, Makoto S., E-mail: urata@astro.ncu.edu.tw [Department of Physics, Saitama University, Shimo-Okubo, Saitama 338-8570 (Japan)

    2012-03-20

    This study presents multi-wavelength observational results for energetic GRB 100414A with GeV photons. The prompt spectral fitting using Suzaku/WAM data yielded spectral peak energies of E{sup src}{sub peak} of 1458.7{sup +132.6}{sub -106.6} keV and E{sub iso} of 34.5{sup +2.0}{sub -1.8} Multiplication-Sign 10{sup 52} erg with z = 1.368. The optical afterglow light curves between 3 and 7 days were effectively fitted according to a simple power law with a temporal index of {alpha} = -2.6 {+-} 0.1. The joint light curve with earlier Swift/UVOT observations yields a temporal break at 2.3 {+-} 0.2 days. This was the first Fermi/LAT detected event that demonstrated the clear temporal break in the optical afterglow. The jet opening angle derived from this temporal break was 5.{sup 0}8, consistent with those of other well-observed long gamma-ray bursts (GRBs). The multi-wavelength analyses in this study showed that GRB 100414A follows E{sup src}{sub peak}-E{sub iso} and E{sup src}{sub peak}-E{sub {gamma}} correlations. The late afterglow revealed a flatter evolution with significant excesses at 27.2 days. The most straightforward explanation for the excess is that GRB 100414A was accompanied by a contemporaneous supernova. The model light curve based on other GRB-SN events is marginally consistent with that of the observed light curve.

  2. A JET BREAK IN THE X-RAY LIGHT CURVE OF SHORT GRB 111020A: IMPLICATIONS FOR ENERGETICS AND RATES

    International Nuclear Information System (INIS)

    Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Czekala, I.; Chornock, R.; Troja, E.; Gehrels, N.; Sakamoto, T.; Fox, D. B.; Podsiadlowski, P.

    2012-01-01

    We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning ∼100 s to 10 days after the burst, reveals a significant break at δt ≈ 2 days with pre- and post-break decline rates of α X,1 ≈ –0.78 and α X,2 ∼ j ≈ 3°-8°. The resulting beaming-corrected γ-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) × 10 48 erg and (0.3-2) × 10 49 erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of c X , constrains the circumburst density to n 0 ∼ 0.01-0.1 cm –3 . Optical observations provide an afterglow limit of i ∼> 24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i ≈ 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0.''80 ± 0.''11 (1σ) from this galaxy corresponding to an offset of 5-7 kpc for z 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5 ± 2.0) × 10 21 cm –2 (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of ∼> 100-1000 Gpc –3 yr –1 , in good agreement with the NS-NS merger rate of ≈200-3000 Gpc –3 yr –1 . This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

  3. AN INDEPENDENT MEASUREMENT OF THE INCIDENCE OF Mg II ABSORBERS ALONG GAMMA-RAY BURST SIGHT LINES: THE END OF THE MYSTERY?

    International Nuclear Information System (INIS)

    Cucchiara, A.; Prochaska, J. X.; Zhu, G.; Ménard, B.; Fynbo, J. P. U.; Fox, D. B.; Chen, H.-W.; Cooksey, K. L.; Cenko, S. B.; Bloom, J. S.; Perley, D.; Berger, E.; Chornock, R.; Tanvir, N. R.; D'Elia, V.; Lopez, S.; De Jaeger, T.

    2013-01-01

    In 2006, Prochter et al. reported a statistically significant enhancement of very strong Mg II absorption systems intervening the sight lines to gamma-ray bursts (GRBs) relative to the incidence of such absorption along quasar sight lines. This counterintuitive result has inspired a diverse set of astrophysical explanations (e.g., dust, gravitational lensing) but none of these has obviously resolved the puzzle. Using the largest set of GRB afterglow spectra available, we reexamine the purported enhancement. In an independent sample of GRB spectra with a survey path three times larger than Prochter et al., we measure the incidence per unit redshift of ≥1 Å rest-frame equivalent width Mg II absorbers at z ≈ 1 to be l(z) = 0.18 ± 0.06. This is fully consistent with current estimates for the incidence of such absorbers along quasar sight lines. Therefore, we do not confirm the original enhancement and suggest those results suffered from a statistical fluke. Signatures of the original result do remain in our full sample (l(z) shows an ≈1.5 enhancement over l(z) QSO ), but the statistical significance now lies at ≈90% c.l. Restricting our analysis to the subset of high-resolution spectra of GRB afterglows (which overlaps substantially with Prochter et al.), we still reproduce a statistically significant enhancement of Mg II absorption. The reason for this excess, if real, is still unclear since there is no connection between the rapid afterglow follow-up process with echelle (or echellette) spectrographs and the detectability of strong Mg II doublets. Only a larger sample of such high-resolution data will shed some light on this matter

  4. AN EXPLANATION FOR THE DIFFERENT X-RAY TO OPTICAL COLUMN DENSITIES IN THE ENVIRONMENTS OF GAMMA RAY BURSTS: A PROGENITOR EMBEDDED IN A DENSE MEDIUM

    International Nuclear Information System (INIS)

    Krongold, Yair; Prochaska, J. Xavier

    2013-01-01

    We study the ∼> 10 ratios in the X-ray to optical column densities inferred from afterglow spectra of gamma ray bursts (GRBs) due to gas surrounding their progenitors. We present time-evolving photoionization calculations for these afterglows and explore different conditions of their environment. We find that homogenous models of the environment (constant density) predict X-ray columns similar to those found in the optical spectra, with the bulk of the opacity being produced by neutral material at large distances from the burst. This result is independent of gas density or metallicity. Only models assuming a progenitor immersed in a dense (∼10 2-4 cm –3 ) cloud of gas (with radius ∼10 pc), with a strong, declining gradient of density for the surrounding interstellar medium (ISM) are able to account for the large X-ray to optical column density ratios. However, to avoid an unphysical correlation between the size of this cloud and the size of the ionization front produced by the GRB, the models also require that the circumburst medium is already ionized prior to the burst. The inferred cloud masses are ∼ 6 M ☉ , even if low metallicities in the medium are assumed (Z ∼ 0.1 Z ☉ ). These cloud properties are consistent with those found in giant molecular clouds and our results support a scenario in which the progenitors reside within intense star formation regions of galaxies. Finally, we show that modeling over large samples of GRB afterglows may offer strong constraints on the range of properties in these clouds, and the host galaxy ISM

  5. Influence of an additional ballast volume on a pulsed ICP discharge

    International Nuclear Information System (INIS)

    Bogdanov, E A; Jr, C A DeJoseph; Demidov, V I; Kudryavtsev, A A; Serditov, K Yu

    2007-01-01

    A spatial and temporal numerical simulation has been carried out of a pulsed (100% modulated), rf inductively coupled plasma discharge in argon, connected to an additional (ballast) diffusion chamber of much larger volume. It is demonstrated that during the active phase, the presence of the large ballast volume has a small impact on the parameters of the plasma in the smaller discharge chamber. In this case the plasma parameters in the discharge chamber can be estimated separately from the diffusion chamber by a standard method using the characteristic ambipolar diffusion time (for example, using a global model). However, during the afterglow phase, the situation is changed significantly. In the afterglow, the densities of charged particles in the discharge chamber become lower than in the large ballast chamber due to more rapid diffusion loss. As a result, the reverse of the active phase situation occurs, namely, the plasma does not flow from the small to the large chamber, but in the opposite direction, from diffusive to discharge volume, and both the plasma density gradient and the self-consistent ambipolar electric field in the small chamber change directions. This phenomenon leads to new effects in the discharge volume, in particular a decreasing rate of decay of densities of charged particles and electron temperature. Thus, in the afterglow the presence of a large additional ballast volume has a significant impact on the plasma transport. In this case, a simple treatment of the plasma in the discharge chamber in the framework of a spatially averaged model (for example, the global model) is inadequate

  6. Dust reddening and extinction curves toward gamma-ray bursts at z > 4

    Science.gov (United States)

    Bolmer, J.; Greiner, J.; Krühler, T.; Schady, P.; Ledoux, C.; Tanvir, N. R.; Levan, A. J.

    2018-01-01

    Context. Dust is known to be produced in the envelopes of asymptotic giant branch (AGB) stars, the expanded shells of supernova (SN) remnants, and in situ grain growth within the interstellar medium (ISM), although the corresponding efficiency of each of these dust formation mechanisms at different redshifts remains a topic of debate. During the first Gyr after the Big Bang, it is widely believed that there was not enough time to form AGB stars in high numbers, hence the dust at this epoch is expected to be purely from SNe or subsequent grain growth in the ISM. The time period corresponding to z 5-6 is thus expected to display the transition from SN-only dust to a mixture of both formation channels as is generally recognized at present. Aims: Here we aim to use afterglow observations of gamma-ray bursts (GRBs) at redshifts larger than z > 4 to derive host galaxy dust column densities along their line of sight and to test if a SN-type dust extinction curve is required for some of the bursts. Methods: We performed GRB afterglow observations with the seven-channel Gamma-Ray Optical and Near-infrared Detector (GROND) at the 2.2 m MPI telescope in La Silla, Chile (ESO), and we combined these observations with quasi-simultaneous data gathered with the XRT telescope on board the Swift satellite. Results: We increase the number of measured AV values for GRBs at z > 4 by a factor of 2-3 and find that, in contrast to samples at mostly lower redshift, all of the GRB afterglows have a visual extinction of AV different scenarios. For the first time we also report a photometric redshift of zphot = 7.88-0.94+0.75 for GRB 100905A, making it one of the most distant GRBs known to date.

  7. AN INDEPENDENT MEASUREMENT OF THE INCIDENCE OF Mg II ABSORBERS ALONG GAMMA-RAY BURST SIGHT LINES: THE END OF THE MYSTERY?

    Energy Technology Data Exchange (ETDEWEB)

    Cucchiara, A.; Prochaska, J. X. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Zhu, G.; Menard, B. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Fynbo, J. P. U. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Fox, D. B. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Chen, H.-W. [Department of Astronomy and Astrophysics, Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Cooksey, K. L. [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-685, Cambridge, MA 02139 (United States); Cenko, S. B.; Bloom, J. S. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Perley, D. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Berger, E.; Chornock, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); D' Elia, V. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Roma, Via di Frascati 33, I-00040 Monte Porzio Catone (RM) (Italy); Lopez, S.; De Jaeger, T., E-mail: acucchia@ucolick.org [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile)

    2013-08-20

    In 2006, Prochter et al. reported a statistically significant enhancement of very strong Mg II absorption systems intervening the sight lines to gamma-ray bursts (GRBs) relative to the incidence of such absorption along quasar sight lines. This counterintuitive result has inspired a diverse set of astrophysical explanations (e.g., dust, gravitational lensing) but none of these has obviously resolved the puzzle. Using the largest set of GRB afterglow spectra available, we reexamine the purported enhancement. In an independent sample of GRB spectra with a survey path three times larger than Prochter et al., we measure the incidence per unit redshift of {>=}1 A rest-frame equivalent width Mg II absorbers at z Almost-Equal-To 1 to be l(z) = 0.18 {+-} 0.06. This is fully consistent with current estimates for the incidence of such absorbers along quasar sight lines. Therefore, we do not confirm the original enhancement and suggest those results suffered from a statistical fluke. Signatures of the original result do remain in our full sample (l(z) shows an Almost-Equal-To 1.5 enhancement over l(z){sub QSO}), but the statistical significance now lies at Almost-Equal-To 90% c.l. Restricting our analysis to the subset of high-resolution spectra of GRB afterglows (which overlaps substantially with Prochter et al.), we still reproduce a statistically significant enhancement of Mg II absorption. The reason for this excess, if real, is still unclear since there is no connection between the rapid afterglow follow-up process with echelle (or echellette) spectrographs and the detectability of strong Mg II doublets. Only a larger sample of such high-resolution data will shed some light on this matter.

  8. ALMA and GMRT Constraints on the Off-axis Gamma-Ray Burst 170817A from the Binary Neutron Star Merger GW170817

    Science.gov (United States)

    Kim, S.; Schulze, S.; Resmi, L.; González-López, J.; Higgins, A. B.; Ishwara-Chandra, C. H.; Bauer, F. E.; de Gregorio-Monsalvo, I.; De Pasquale, M.; de Ugarte Postigo, A.; Kann, D. A.; Martín, S.; Oates, S. R.; Starling, R. L. C.; Tanvir, N. R.; Buchner, J.; Campana, S.; Cano, Z.; Covino, S.; Fruchter, A. S.; Fynbo, J. P. U.; Hartmann, D. H.; Hjorth, J.; Jakobsson, P.; Levan, A. J.; Malesani, D.; Michałowski, M. J.; Milvang-Jensen, B.; Misra, K.; O’Brien, P. T.; Sánchez-Ramírez, R.; Thöne, C. C.; Watson, D. J.; Wiersema, K.

    2017-12-01

    Binary neutron-star mergers (BNSMs) are among the most readily detectable gravitational-wave (GW) sources with the Laser Interferometer Gravitational-wave Observatory (LIGO). They are also thought to produce short γ-ray bursts (SGRBs) and kilonovae that are powered by r-process nuclei. Detecting these phenomena simultaneously would provide an unprecedented view of the physics during and after the merger of two compact objects. Such a Rosetta Stone event was detected by LIGO/Virgo on 2017 August 17 at a distance of ∼44 Mpc. We monitored the position of the BNSM with Atacama Large Millimeter/submillimeter Array (ALMA) at 338.5 GHz and the Giant Metrewave Radio Telescope (GMRT) at 1.4 GHz, from 1.4 to 44 days after the merger. Our observations rule out any afterglow more luminous than 3× {10}26 {erg} {{{s}}}-1 {{Hz}}-1 in these bands, probing >2–4 dex fainter than previous SGRB limits. We match these limits, in conjunction with public data announcing the appearance of X-ray and radio emission in the weeks after the GW event, to templates of off-axis afterglows. Our broadband modeling suggests that GW170817 was accompanied by an SGRB and that the γ-ray burst (GRB) jet, powered by {E}{AG,{iso}}∼ {10}50 erg, had a half-opening angle of ∼ 20^\\circ , and was misaligned by ∼ 41^\\circ from our line of sight. The data are also consistent with a more collimated jet: {E}{AG,{iso}}∼ {10}51 erg, {θ }1/2,{jet}∼ 5^\\circ ,{θ }{obs}∼ 17^\\circ . This is the most conclusive detection of an off-axis GRB afterglow and the first associated with a BNSM-GW event to date. We use the viewing angle estimates to infer the initial bulk Lorentz factor and true energy release of the burst.

  9. Nonlocal effects in a bounded low-temperature plasma with fast electrons

    International Nuclear Information System (INIS)

    DeJoseph, C. A. Jr.; Demidov, V. I.; Kudryavtsev, A. A.

    2007-01-01

    Effects associated with nonlocality of the electron energy distribution function (EEDF) in a bounded, low-temperature plasma containing fast electrons, can lead to a significant increase in the near-wall potential drop, leading to self-trapping of fast electrons in the plasma volume, even if the density of this group is only a small fraction (∼0.001%) of the total electron density. If self-trapping occurs, the fast electrons can substantially increase the rate of stepwise excitation, supply additional heating to slow electrons, and reduce their rate of diffusion cooling. Altering the source terms of these fast electrons will, therefore, alter the near-wall sheath and, through modification of the EEDF, a number of plasma parameters. Self-trapping of fast electrons is important in a variety of plasmas, including hollow-cathode discharges and capacitive rf discharges, and is especially pronounced in an afterglow plasma, which is a key phase of any pulse-modulated discharge. In the afterglow, the electron temperature is less than a few tenths of an electron volt, and the fast electrons will have energies typically greater than an electron volt. It is shown that in the afterglow plasma of noble gases, fast electrons, arising from Penning ionization of metastable atoms, can lead to the above condition and significantly change the plasma and sheath properties. Similar effects can be important in technologically relevant electronegative gas plasmas, where fast electrons can arise due to electron detachment in collisions of negative ions with atomic species. Both experimental and modeling results are presented to illustrate these effects

  10. Magnetar giant flares in multipolar magnetic fields. II. Flux rope eruptions with current sheets

    International Nuclear Information System (INIS)

    Huang, Lei; Yu, Cong

    2014-01-01

    We propose a physical mechanism to explain giant flares and radio afterglows in terms of a magnetospheric model containing both a helically twisted flux rope and a current sheet (CS). With the appearance of a CS, we solve a mixed boundary value problem to get the magnetospheric field based on a domain decomposition method. We investigate properties of the equilibrium curve of the flux rope when the CS is present in background multipolar fields. In response to the variations at the magnetar surface, it quasi-statically evolves in stable equilibrium states. The loss of equilibrium occurs at a critical point and, beyond that point, it erupts catastrophically. New features show up when the CS is considered. In particular, we find two kinds of physical behaviors, i.e., catastrophic state transition and catastrophic escape. Magnetic energy would be released during state transitions. This released magnetic energy is sufficient to drive giant flares, and the flux rope would, therefore, go away from the magnetar quasi-statically, which is inconsistent with the radio afterglow. Fortunately, in the latter case, i.e., the catastrophic escape, the flux rope could escape the magnetar and go to infinity in a dynamical way. This is more consistent with radio afterglow observations of giant flares. We find that the minor radius of the flux rope has important implications for its eruption. Flux ropes with larger minor radii are more prone to erupt. We stress that the CS provides an ideal place for magnetic reconnection, which would further enhance the energy release during eruptions.

  11. Plasma Decontamination of Space Equipment for Planetary Protection

    Science.gov (United States)

    Thomas, Hubertus; Barczyk, Simon; Rettberg, Petra; Shimizu, Satoshi; Shimizu, Tetsuji; Klaempfl, Tobias; Morfill, Gregor; Zimmermann, Julia; Weber, Peter

    The search for extraterrestrial life is one of the most challenging science topics for the next decades. Space missions, like ExoMars, plan to land and search for biological remnants on planets and moons in our nearby Solar system. Planetary protection regulations defined by COSPAR prevent that during the mission biological contamination of the bodies occur through the space probes. Therefore decontamination of the probes and more general space equipment is necessary before the launch. The up-to-date accepted decontamination procedure originate from the old NASA Viking missions and use dry heat (T>110°C for 30h) - a technology not well suited for sensitive equipment nowadays. We investigated in a study financed by the German Space Agency* cold atmospheric plasma (CAP) as an alternative for such decontamination. It is well known that CAP can kill bacteria or spores within seconds or minutes, respectively, if the plasma is in direct contact with the treated sample. This procedure might also be quite aggressive to the treated surface materials. Therefore, we developed an afterglow CAP device specially designed for the soft treatment of space equipment. Afterglow plasma produced by a SMD device in air is transported into a “larger” treatment chamber where the samples are positioned. It could be shown that samples of different bacteria and spores, the latter defined by COSPAR as a means to show the effectiveness of the decontamination process, positioned on different materials (steel, Teflon, quartz) could be effectively inactivated. The surface materials were investigated after the plasma treatment to identify etching or deposition problems. The afterglow in the treatment chamber could even overcome obstacles (tubes of different height and diameter) which simulate more complicated structures of the relevant surfaces. Up to now, CAP looks like a quite promising alternative to decontaminate space equipment and need to be studied in greater detail in the near future

  12. Highly polarized light from stable ordered magnetic fields in GRB 120308A.

    Science.gov (United States)

    Mundell, C G; Kopač, D; Arnold, D M; Steele, I A; Gomboc, A; Kobayashi, S; Harrison, R M; Smith, R J; Guidorzi, C; Virgili, F J; Melandri, A; Japelj, J

    2013-12-05

    After the initial burst of γ-rays that defines a γ-ray burst (GRB), expanding ejecta collide with the circumburst medium and begin to decelerate at the onset of the afterglow, during which a forward shock travels outwards and a reverse shock propagates backwards into the oncoming collimated flow, or 'jet'. Light from the reverse shock should be highly polarized if the jet's magnetic field is globally ordered and advected from the central engine, with a position angle that is predicted to remain stable in magnetized baryonic jet models or vary randomly with time if the field is produced locally by plasma or magnetohydrodynamic instabilities. Degrees of linear polarization of P ≈ 10 per cent in the optical band have previously been detected in the early afterglow, but the lack of temporal measurements prevented definitive tests of competing jet models. Hours to days after the γ-ray burst, polarization levels are low (P < 4 per cent), when emission from the shocked ambient medium dominates. Here we report the detection of P =28(+4)(-4) per cent in the immediate afterglow of Swift γ-ray burst GRB 120308A, four minutes after its discovery in the γ-ray band, decreasing to P = 16(+5)(-4) per cent over the subsequent ten minutes. The polarization position angle remains stable, changing by no more than 15 degrees over this time, with a possible trend suggesting gradual rotation and ruling out plasma or magnetohydrodynamic instabilities. Instead, the polarization properties show that GRBs contain magnetized baryonic jets with large-scale uniform fields that can survive long after the initial explosion.

  13. The first gamma-ray bursts in the universe

    International Nuclear Information System (INIS)

    Mesler, R. A.; Pihlström, Y. M.; Whalen, Daniel J.; Smidt, Joseph; Fryer, Chris L.; Lloyd-Ronning, N. M.

    2014-01-01

    Gamma-ray bursts (GRBs) are the ultimate cosmic lighthouses, capable of illuminating the universe at its earliest epochs. Could such events probe the properties of the first stars at z ∼ 20, the end of the cosmic Dark Ages? Previous studies of Population III (Pop III) GRBs only considered explosions in the diffuse relic H II regions of their progenitors or bursts that are far more energetic than those observed to date. However, the processes that produce GRBs at the highest redshifts likely reset their local environments, creating much more complicated structures than those in which relativistic jets have been modeled so far. These structures can greatly affect the luminosity of the afterglow and hence the redshift at which it can be detected. We have now simulated Pop III GRB afterglows in H II regions, winds, and dense shells ejected by the star during the processes that produce the burst. We find that GRBs with E iso,γ = 10 51 -10 53 erg will be visible at z ≳ 20 to the next generation of near infrared and radio observatories. In many cases, the environment of the burst, and hence progenitor type, can be inferred from the afterglow light curve. Although some Pop III GRBs are visible to Swift and the Very Large Array now, the optimal strategy for their detection will be future missions like the proposed EXIST and JANUS missions with large survey areas and onboard X-ray and infrared telescopes that can track their near-infrared flux from the moment of the burst, thereby identifying their redshifts.

  14. X-Ray Spectral Diagnostics of Gamma-Ray Burst Environments.

    Science.gov (United States)

    Paerels; Kuulkers; Heise; Liedahl

    2000-05-20

    Recently, detection of discrete features in the X-ray afterglow spectra of GRB 970508 and GRB 970828 was reported. The most natural interpretation of these features is that they are redshifted Fe K emission complexes. The identification of the line emission mechanism has drastic implications for the inferred mass of radiating material and hence the nature of the burst site. X-ray spectroscopy provides a direct observational constraint on these properties of gamma-ray bursters. We briefly discuss how these constraints arise in the context of an application to the spectrum of GRB 970508.

  15. Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; hide

    2013-01-01

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  16. Probing Pre-Galactic Metal Enrichment with High-Redshift Gamma-Ray Bursts

    Science.gov (United States)

    Wang, F. Y.; Bromm, Volker; Greif, Thomas H.; Stacy, Athena; Dai, Z. G.; Loeb, Abraham; Cheng, K. S.

    2012-01-01

    We explore high-redshift gamma-ray bursts (GRBs) as promising tools to probe pre-galactic metal enrichment. We utilize the bright afterglow of a Population III (Pop III) GRB exploding in a primordial dwarf galaxy as a luminous background source, and calculate the strength of metal absorption lines that are imprinted by the first heavy elements in the intergalactic medium (IGM). To derive the GRB absorption line diagnostics, we use an existing highly resolved simulation of the formation of a first galaxy which is characterized by the onset of atomic hydrogen cooling in a halo with virial temperature approximately greater than10(exp 4) K.We explore the unusual circumburst environment inside the systems that hosted Pop III stars, modeling the density evolution with the self-similar solution for a champagne flow. For minihalos close to the cooling threshold, the circumburst density is roughly proportional to (1 + z) with values of about a few cm(exp -3). In more massive halos, corresponding to the first galaxies, the density may be larger, n approximately greater than100 cm(exp -3). The resulting afterglow fluxes are weakly dependent on redshift at a fixed observed time, and may be detectable with the James Webb Space Telescope and Very Large Array in the near-IR and radio wavebands, respectively, out to redshift z approximately greater than 20. We predict that the maximum of the afterglow emission shifts from near-IR to millimeter bands with peak fluxes from mJy to Jy at different observed times. The metal absorption line signature is expected to be detectable in the near future. GRBs are ideal tools for probing the metal enrichment in the early IGM, due to their high luminosities and featureless power-law spectra. The metals in the first galaxies produced by the first supernova (SN) explosions are likely to reside in low-ionization stages (C II, O I, Si II and Fe II). We show that, if the afterglow can be observed sufficiently early, analysis of the metal lines may

  17. Search for chameleon particles via photon regeneration

    International Nuclear Information System (INIS)

    Chou, Aaron S.; CCPP, New York U.

    2008-01-01

    We report the first results from the GammeV search for chameleon particles, which may be created via photon-photon interactions within a strong magnetic field. The chameleons are assumed to have matter effects sufficiently strong that they reflect from all solid surfaces of the apparatus, thus evading detection in our previous search for weakly-interacting axion-like particles. We implement a novel technique to create and trap the reflective particles within a jar and to detect them later via their afterglow as they slowly convert back into photons. These measurements provide the first experimental constraints on the couplings of chameleons to photons

  18. Search for Chameleon Particles Using a Photon-Regeneration Technique

    International Nuclear Information System (INIS)

    Chou, A. S.; Wester, W.; Baumbaugh, A.; Irizarry-Valle, Y.; Mazur, P. O.; Steffen, J. H.; Tomlin, R.; Yang, X.; Yoo, J.; Gustafson, H. R.; Upadhye, A.; Weltman, A.

    2009-01-01

    We report the first results from the GammeV search for chameleon particles, which may be created via photon-photon interactions within a strong magnetic field. Chameleons are hypothesized scalar fields that could explain the dark energy problem. We implement a novel technique to create and trap the reflective particles within a jar and to detect them later via their afterglow as they slowly convert back into photons. These measurements provide the first experimental constraints on the couplings of chameleons to photons

  19. Laboratory constraints on chameleon dark energy and power-law fields

    International Nuclear Information System (INIS)

    Steffen, Jason H.; Upadhye, Amol; Baumbaugh, Al; Chou, Aaron S.; Mazur, Peter O.; Tomlin, Ray; Weltman, Amanda; Wester, William

    2010-01-01

    We report results from the GammeV Chameleon Afterglow Search - a search for chameleon particles created via photon/chameleon oscillations within a magnetic field. This experiment is sensitive to a wide class of chameleon power-law models and dark energy models not previously explored. These results exclude five orders of magnitude in the coupling of chameleons to photons covering a range of four orders of magnitude in chameleon effective mass and, for individual chameleon models, exclude between 4 and 12 orders of magnitude in chameleon couplings to matter.

  20. Absolute measurements of light emission from CO2/+/ and CO in the interaction of He/2 super 3 S/ with CO2.

    Science.gov (United States)

    Wauchop, T. S.; Broida, H. P.

    1972-01-01

    A flowing afterglow has been used to produce metastable He(2 super 3 S). It is shown that when He(2 super 3 S) interacts with a diatomic or triatomic molecule, its electronic excitation energy can be transferred to electronic and vibrational excitation of the molecule. To examine this mechanism, the rates for the production of electronically excited molecules, observed spectroscopically between 190 and 750 nm in the reaction of He(2 super 3 S) with CO2, have been measured. Results are tabulated.

  1. Production and loss of HC3N in interstellar clouds: some relevant laboratory measurements

    International Nuclear Information System (INIS)

    Knight, J.S.; Freeman, C.G.; McEwan, M.J.; Smith, S.C.; Adams, N.G.; Smith, D.

    1986-01-01

    The results of recent selected ion flow tube (SIFT) experiments on the ion-molecule chemistry of cyanoacetylene are considered in the context of the chemistry of HC 3 N in the interstellar environment. Important errors revealed by this SIFT investigation, following an earlier flowing afterglow study in the authors' laboratory, have led to a different perception of the ion-molecule chemistry that HC 3 N may undergo in interstellar clouds. It is now evident that insertion and association occur in the reactions of hydrocarbon ions with HC 3 N. (author)

  2. Program and abstracts

    International Nuclear Information System (INIS)

    1978-01-01

    This volume contains the program and abstracts of the conference. The following topics are included: metal vapor molecular lasers, magnetohydrodynamics, rare gas halide and nuclear pumped lasers, transfer mechanisms in arcs, kinetic processes in rare gas halide lasers, arcs and flows, XeF kinetics and lasers, fundamental processes in excimer lasers, electrode effects and vacuum arcs, electron and ion transport, ion interactions and mobilities, glow discharges, diagnostics and afterglows, dissociative recombination, electron ionization and excitation, rare gas excimers and group VI lasers, breakdown, novel laser pumping techniques, electrode-related discharge phenomena, photon interactions, attachment, plasma chemistry and infrared lasers, electron scattering, and reactions of excited species

  3. Search for Chameleon Scalar Fields with the Axion Dark Matter Experiment

    International Nuclear Information System (INIS)

    Rybka, G.; Hotz, M.; Rosenberg, L. J; Asztalos, S. J.; Carosi, G.; Hagmann, C.; Kinion, D.; van Bibber, K.; Hoskins, J.; Martin, C.; Sikivie, P.; Tanner, D. B.; Bradley, R.; Clarke, J.

    2010-01-01

    Scalar fields with a 'chameleon' property, in which the effective particle mass is a function of its local environment, are common to many theories beyond the standard model and could be responsible for dark energy. If these fields couple weakly to the photon, they could be detectable through the afterglow effect of photon-chameleon-photon transitions. The ADMX experiment was used in the first chameleon search with a microwave cavity to set a new limit on scalar chameleon-photon coupling β γ excluding values between 2x10 9 and 5x10 14 for effective chameleon masses between 1.9510 and 1.9525 μeV.

  4. Binary recombination of para- and ortho-H3+ with electrons at low temperatures.

    Science.gov (United States)

    Dohnal, P; Hejduk, M; Varju, J; Rubovic, P; Roucka, S; Kotrík, T; Plasil, R; Johnsen, R; Glosík, J

    2012-11-13

    Results of an experimental study of binary recombination of para- and ortho-H(3)(+) ions with electrons are presented. Near-infrared cavity-ring-down absorption spectroscopy was used to probe the lowest rotational states of H(3)(+) ions in the temperature range of 77-200 K in an H(3)(+)-dominated afterglow plasma. By changing the para/ortho abundance ratio, we were able to obtain the binary recombination rate coefficients for pure and para-H(3)(+) and ortho-H(3)(+). The results are in good agreement with previous theoretical predictions.

  5. Studium rekombinace H3+ ve vybranych kvantových stavech

    OpenAIRE

    Varju, Jozef

    2011-01-01

    Title: Study of H3 + recombination in selected quantum states Author: Jozef Varju Department : Department of Surface and Plasma Science Supervisor of the doctoral thesis: Prof. RNDr. Juraj Glosík, DrSc., Department of Surface and Plasma Science Abstract: In this work measurement of the effective recombination rate coefficient of H3 + dominated and recombination governed afterglow plasma at 77 K and 145 K are presented. Population of para-H3 + in the studied plasma has been varied by using par...

  6. Enhanced luminescent properties of long-persistent Sr{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+}, Dy{sup 3+} phosphor prepared by the co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Pan Wen [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Zhongshan Road 158-43, Dalian Liaoning 116012 (China); Ning Guiling [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Zhongshan Road 158-43, Dalian Liaoning 116012 (China)], E-mail: ninggl@dlut.edu.cn; Zhang Xu; Wang Jing; Lin Yuan; Ye Junwei [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Zhongshan Road 158-43, Dalian Liaoning 116012 (China)

    2008-12-15

    Sr{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+}, Dy{sup 3+} phosphors were prepared by the (aminopropyl)-triethoxysilane (APTES) co-precipitation method. Effects of synthesis temperature on the crystal characteristics, luminescent properties and afterglow performance of Sr{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+}, Dy{sup 3+} phosphors have been discussed in detail and compared with the corresponding commercial product. The experimental results indicated that the sample could be synthesized at a relatively lower temperature and had better performance on the above-mentioned properties using the co-precipitation method.

  7. X-ray astronomy 2000: Wide field X-ray monitoring with lobster-eye telescopes

    International Nuclear Information System (INIS)

    Inneman, A.; Hudec, R.; Pina, L.; Gorenstein, P.

    2001-01-01

    The recently available first prototypes of innovative very wide field X-ray telescopes of Lobster-Eye type confirm the feasibility to develop such flight instruments in a near future. These devices are expected to allow very wide field (more than 1000 square degrees) monitoring of the sky in X-rays (up to 10 keV and perhaps even more) with faint limits. We will discuss the recent status of the development of very wide field X-ray telescopes as well as related scientific questions including expected major contributions such as monitoring and study of X-ray afterglows of Gamma Ray Bursts

  8. Trapping processes in CaS:Eu2+,Tm3+

    International Nuclear Information System (INIS)

    Jia, Dongdong; Jia, Weiyi; Evans, D. R.; Dennis, W. M.; Liu, Huimin; Zhu, Jing; Yen, W. M.

    2000-01-01

    CaS:Eu 2+ ,Tm 3+ is a persistent red phosphor. Thermoluminescence was measured under different excitation and thermal treatment conditions. The results reveal that the charge defects, created by substituting Tm 3+ for Ca 2+ , serve as hole traps for the afterglow at room temperature. Tm 3+ plays the role of deep electron trapping centers, capturing electrons either through the conduction band or directly from the excited Eu 2+ ions. These two processes, in which two different sites of Tm 3+ are involved, correspond to two traps with different depths. (c) 2000 American Institute of Physics

  9. The recombination of a helium plasma

    International Nuclear Information System (INIS)

    Hollenstein, C.; Sayasov, Y.; Schneider, H.

    1975-01-01

    A helium plasma (Tsub(e) 15 cm -3 ) in the afterglow without magnetic field was investigated. The measurements of the electron density and temperature are presented. Laser interferometry and radiowave diagnostics were used. The measured exponential decay of the electron density and temperature was explained with the collisional-radiative recombination and the thermal conduction of the electrons towards the wall of the discharge vessel. The measured recombination coefficients were compared with measurements and calculations of other authors. The best agreement was found with the calculations by Drawin. (Auth.)

  10. Recombination of H(3+) and D(3+) ions with electrons

    Science.gov (United States)

    Johnsen, R.; Gougousi, T.; Golde, M. F.

    1994-01-01

    Flowing-afterglow measurements in decaying H3(+) or D3(+) plasmas suggest that de-ionization does not occur by simple binary recombination of a single ion species. We find that vibrational excitation of the ions fails to provide an explanation for the effect, contrary to an earlier suggestion. Instead, we suggest that collisional stabilization of H3** Rydberg molecules by ambient electrons introduces an additional dependence on electron density. The proposed mechanism would permit plasma de-ionization to occur without the need for dissociative recombination by the mechanism of potential-surface crossings.

  11. Ions and light

    CERN Document Server

    Bowers, Michael T

    2013-01-01

    Gas Phase Ion Chemistry, Volume 3: Ions and Light discusses how ions are formed by electron impact, ion-molecule reactions, or electrical discharge. This book discusses the use of light emitted by excited molecules to characterize either the chemistry that formed the excited ion, the structure of the excited ion, or both.Organized into 10 chapters, this volume begins with an overview of the extension of the classical flowing afterglow technique to include infrared and chemiluminescence and laser-induced fluorescence detection. This text then examines the experiments involving molecules that ar

  12. The slewing mirror telescope of the Ultra Fast Flash Observatory Pathfinder

    DEFF Research Database (Denmark)

    Jeong, S.; Ahmad, S.; Barrillon, P.

    2012-01-01

    The Slewing Mirror Telescope (SMT) is a key telescope of Ultra-Fast Flash Observatory (UFFO) space project to explore the first sub-minute or sub-seconds early photons from the Gamma Ray Bursts (GRBs) afterglows. As the realization of UFFO, 20kg of UFFO-Pathfinder (UFFO-P) is going to be on board...... the Russian Lomonosov satellite in November 2012 by Soyuz-2 rocket. Once the UFFO Burst Alert & Trigger Telescope (UBAT) detects the GRBs, Slewing mirror (SM) will slew to bring new GRB into the SMT’s field of view rather than slewing the entire spacecraft. SMT can give a UV/Optical counterpart position...

  13. Possible Correlations between the Emission Properties of SGRBs and Their Offsets from the Host Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuai; Jin, Zhi-Ping; Li, Xiang; Fan, Yi-Zhong; Wei, Da-Ming [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, 210008 (China); Zhang, Fu-Wen, E-mail: jin@pmo.ac.cn, E-mail: yzfan@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [College of Science, Guilin University of Technology, Guilin 541004 (China)

    2017-07-20

    Short gamma-ray bursts (SGRBs) are widely believed to be from mergers of binary compact objects involving at least one neutron star and hence have a broad range of spatial offsets from their host galaxies. In this work, we search for possible correlations between the emission properties of 18 SGRBs and their offsets from the host galaxies. The SGRBs with and without extended emission do not show significant differences between their offset distributions, in agreement with some previous works. There are, however, possible correlations between the optical and X-ray afterglow emission and the offsets. The underlying physical origins are examined.

  14. Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

    DEFF Research Database (Denmark)

    Canulescu, Stela; Molchan, Igor S.; Tauziede, C.

    2010-01-01

    A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime...... be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible...... for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed....

  15. Observational tests of the Electro-Magnetic Black Hole Theory in Gamma-Ray Bursts

    OpenAIRE

    Ruffini, Remo

    2002-01-01

    The Relative Space-Time Transformation (RSTT) Paradigm and the Interpretation of the Burst Structure (IBS) Paradigm are applied to the analysis of the structure of the burst and afterglow of Gamma-Ray Bursts within the theory based on the vacuum polarization process occurring in an Electro-Magnetic Black Hole, the EMBH theory. This framework is applied to the study of the GRB991216 which is used as a prototype. The GRB-Supernova Time Sequence (GSTS) Paradigm, which introduces the concept of i...

  16. Impact of intense x-ray pulses on a NaI(Tl)-based gamma camera

    Science.gov (United States)

    Koppert, W. J. C.; van der Velden, S.; Steenbergen, J. H. L.; de Jong, H. W. A. M.

    2018-03-01

    In SPECT/CT systems x-ray and γ-ray imaging is performed sequentially. Simultaneous acquisition may have advantages, for instance in interventional settings. However, this may expose a gamma camera to relatively high x-ray doses and deteriorate its functioning. We studied the NaI(Tl) response to x-ray pulses with a photodiode, PMT and gamma camera, respectively. First, we exposed a NaI(Tl)-photodiode assembly to x-ray pulses to investigate potential crystal afterglow. Next, we exposed a NaI(Tl)-PMT assembly to 10 ms LED pulses (mimicking x-ray pulses) and measured the response to flashing LED probe-pulses (mimicking γ-pulses). We then exposed the assembly to x-ray pulses, with detector entrance doses of up to 9 nGy/pulse, and analysed the response for γ-pulse variations. Finally, we studied the response of a Siemens Diacam gamma camera to γ-rays while exposed to x-ray pulses. X-ray exposure of the crystal, read out with a photodiode, revealed 15% afterglow fraction after 3 ms. The NaI(Tl)-PMT assembly showed disturbances up to 10 ms after 10 ms LED exposure. After x-ray exposure however, responses showed elevated baselines, with 60 ms decay-time. Both for x-ray and LED exposure and after baseline subtraction, probe-pulse analysis revealed disturbed pulse height measurements shortly after exposure. X-ray exposure of the Diacam corroborated the elementary experiments. Up to 50 ms after an x-ray pulse, no events are registered, followed by apparent energy elevations up to 100 ms after exposure. Limiting the dose to 0.02 nGy/pulse prevents detrimental effects. Conventional gamma cameras exhibit substantial dead-time and mis-registration of photon energies up to 100 ms after intense x-ray pulses. This is due PMT limitations and due to afterglow in the crystal. Using PMTs with modified circuitry, we show that deteriorative afterglow effects can be reduced without noticeable effects on the PMT performance, up to x-ray pulse doses of 1 nGy.

  17. Atomic and molecular sciences. Progress report No. 8, April 1, 1981-March 31, 1982

    International Nuclear Information System (INIS)

    Walters, G.K.; Lane, N.F.

    1981-01-01

    The atomic and molecular physics program at Rice University addresses fundamental problems in structure, radiation-induced gas- and condensed-phase reaction kinetics and dynamics, and the mutual interactions of radiation, atoms, molecules, electrons and ions, particularly in highly unusual or exotic environments. The program emphasizes fundamental studies relating to new sources of energy, with close interaction between experimental and theoretical aspects of the research. Progress in the experimental program is reported in two principal areas, A) time resolved spectroscopy, and B) reactions in a flowing helium afterglow

  18. Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local

    Science.gov (United States)

    Heintz, K. E.; Fynbo, J. P. U.; Jakobsson, P.; Krühler, T.; Christensen, L.; Watson, D.; Ledoux, C.; Noterdaeme, P.; Perley, D. A.; Rhodin, H.; Selsing, J.; Schulze, S.; Tanvir, N. R.; Møller, P.; Goldoni, P.; Xu, D.; Milvang-Jensen, B.

    2017-05-01

    We present the spectroscopic and photometric late-time follow-up of the host galaxy of the long-duration Swift γ-ray burst GRB 140506A at z = 0.889. The optical and near-infrared afterglow of this GRB had a peculiar spectral energy distribution (SED) with a strong flux-drop at 8000 Å (4000 Å rest-frame) suggesting an unusually steep extinction curve. By analysing the contribution and physical properties of the host galaxy, we here aim at providing additional information on the properties and origin of this steep, non-standard extinction. We find that the strong flux-drop in the GRB afterglow spectrum at contamination by the host galaxy light at short wavelengths so that the scenario with an extreme 2175 Å extinction bump can be excluded. We localise the GRB to be at a projected distance of approximately 4 kpc from the centre of the host galaxy. Based on emission-line diagnostics of the four detected nebular lines, Hα, Hβ, [O II] and [O III], we find the host to be a modestly star forming (SFR = 1.34 ± 0.04 M⊙ yr-1) and relatively metal poor (Z=0.35+0.15-0.11 Z⊙) galaxy with a large dust content, characterised by a measured visual attenuation of AV = 1.74 ± 0.41 mag. We compare the host to other GRB hosts at similar redshifts and find that it is unexceptional in all its physical properties. We model the extinction curve of the host-corrected afterglow and show that the standard dust properties causing the reddening seen in the Local Group are inadequate in describing the steep drop. We thus conclude that the steep extinction curve seen in the afterglow towards the GRB is of exotic origin and issightline-dependent only, further confirming that this type of reddening is present only at very local scales and that it is solely a consequence of the circumburst environment. Based on observations carried out under programme IDs 095.D-0043(A, C) and 095.A-0045(A) with the X-shooter spectrograph and the FOcal Reducer and low dispersion Spectrograph 2 (FORS2

  19. Time evolution of plasma potential in pulsed operation of ECRIS

    International Nuclear Information System (INIS)

    Tarvainen, O.; Koivisto, H.; Ropponen, T.; Toivanen, V.; Higurashi, Y.; Nakagawa, T.

    2012-01-01

    The time evolution of plasma potential has been measured with a retarding field analyzer in pulsed operation mode with electron cyclotron resonance ion sources at JYFL and RIKEN. Three different ion sources with microwave frequencies ranging from 6.4 to 18 GHz were employed for the experiments. The plasma potential was observed to increase 10-75 % during the Pre-glow and 10-30 % during the afterglow compared to steady state. The paper is followed by the slides of the presentation. (authors)

  20. Calculation of rate coefficients of some proton-transfer ion-molecule reactions in weakly ionized gases

    International Nuclear Information System (INIS)

    Stiller, W.

    1985-01-01

    A classical collision theory is used to describe thermal bimolecular rate coefficeints for reaction between positive and negative ions and polar molecules in a carrier gas. Special attention is paid to ion-molecule reaction in which proton transfer occurs. These reactions play an important role in terrestrial plasma devices, in ionosphere, in planetary atmospheres and in interstellar matter. The equilibrium rate coefficients of the reactions are calculated based on a microscopic reactive cross section derived from a long distance polar molecule-ion potential. The results are compared with experimental values of afterglow measurements. (D.Gy.)

  1. Atomic physics center in 1972. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, D

    1973-12-31

    The activities of the Toulouse Atomic Physics Center in 1972 are presented. Each research group of the atomic physics section is dealt with separately: atomic collisions, afterglow in gases, dc discharges in medium and high pressure gases, electric arcs, the physics of dielectrics, transport of radiation in matter, stimulated electronic emission, and pn semiconductor junctions. Because of its size, the aerosol and atmospheric exchanges section was not divided into different research groups; the work carried out by this section is presented as a single overall account. (auth)

  2. Apparent wavelength shifts of H-like ions caused by the spectral fine structure observed in CHS plasmas

    International Nuclear Information System (INIS)

    Nishimura, Shin; Ida, Katsumi

    1998-01-01

    A new charge exchange spectroscopy (CXS) system viewing the plasma from the upside and the downside simultaneously was installed on the Compact Helical System (CHS) to detect the absolute value of Doppler shift due to poloidal rotation velocity ( i ∼ 100 eV) and in the after-glow recombining phase (T i ∼ 30 eV). The apparent Doppler shift is always red-shift regardless the direction of plasma rotation and is explained as the effect of the spectral fine structure of hydrogen-like ions. (author)

  3. Re-ionization of a partially ionized plasma by an Alfven wave of moderate amplitude

    International Nuclear Information System (INIS)

    Brennan, M.H.; Sawley, M.L.

    1980-01-01

    The use of forced magnetic-acoustic oscillations to investigate the effect of a torsional hydromagnetic (Alfven) wave pulse of moderate amplitude on the properties of a partially ionized afterglow helium plasma is reported. Observations of the magnetic flux associated with the oscillations, measured at a number of frequencies are used to determine radial density profiles and to provide estimates of plasma temperature. The torsional wave is shown to cause significant re-ionization of the plasma with no corresponding increase in the plasma temperature. The presence of a number of energetic particles is evidenced by the production of a significant number of doubly charged helium ions. (author)

  4. Development of scintillators on the basis of AIIBVI compounds for radiation instruments used in medical and technical applications

    Directory of Open Access Journals (Sweden)

    Starzhinskiy N. G.

    2009-06-01

    Full Text Available Physico-technological problems of preparation and main properties of scintillation materials based on zinc selenide and other AIIBVI compounds are considered. Effects have been determined of dopant properties on formation processes of complex lattice defects playing the role of luminescence centers. It is shown that such property features as high light output and very low afterglow level, as well as a unique combination of scintillation and semiconductor properties allow application of these materials in different fields of radiation instrument technologies.

  5. Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  6. Report on the scientific activity for the CRP on data for molecular processes in edge plasmas

    International Nuclear Information System (INIS)

    Schneider, I.F.; Crumeyrolle, O.; Suzor-Weiner, A.; Florescu, A.I.; Motapon, O.; Nana Ngassam, V.; Waffeu Tamo, F.O.; Fifirig, M.; Stroe, M.C.

    2006-01-01

    Reactive collisions between electrons and molecular ions of hydrogen and oxides, relevant for fusion plasma kinetics have been investigated. The main results (advances in modelling and computed rates) achieved are: Reactive collisions between electrons and H 2 + ions at low energy (0.0001-1 eV): dissociative recombination, superelastic collisions, inelastic collisions and elastic collisions; Computation and comparison with TSR storage ring experimental data; Rigorous theory for intermediate energy; Critical update of molecular data (states and interactions) for H 2 and isotopes; computation and comparison with flowing afterglow Langmuir probe plasma experiments

  7. Recombination in deuterium plasma at cryogenic temperatures (down to 130 K)

    Energy Technology Data Exchange (ETDEWEB)

    Novotny, O.; Glosik, J.; Pysanenko, A.; Zakouril, P.; Plasil, R.; Tichy, M. [Prague Charles Univ., Faculty of Mathematics and Physics (Czech Republic)

    2004-07-01

    The ions H{sub 3}{sup +} and D{sub 3}{sup +} play an important role in the kinetics of media of astrophysical interest but also in laboratory produced plasmas (discharges, fusion plasmas). In the presented study variable temperature flowing afterglow with Langmuir probe (VT-FALP) was used to study plasma decay in D{sub 2}/He mixture at temperatures down to 130 K and total pressure up to 10 Torr. Large extend of partial number densities of D{sub 2} (10{sup 12} - 3 x 10{sup 15} cm{sup -3}) were used in the experiments. Langmuir probes and mass spectrometers were applied to monitor decay of the plasma during the afterglow. The study is a continuation of our previous measurements of recombination rate coefficients of D{sub 3}{sup +} and D{sub 5}{sup +} ions. In these studies we observed dependence of the recombination rate coefficient on partial pressure of deuterium indicating that third-body assisted recombination is efficient and significantly contributes to recombination in decaying deuterium-containing plasma. (authors)

  8. MAGNETIC FIELDS AND COSMIC RAYS IN GRBs: A SELF-SIMILAR COLLISIONLESS FORESHOCK

    International Nuclear Information System (INIS)

    Medvedev, Mikhail V.; Zakutnyaya, Olga V.

    2009-01-01

    Cosmic rays accelerated by a shock form a streaming distribution of outgoing particles in the foreshock region. If the ambient fields are negligible compared to the shock and cosmic ray energetics, a stronger magnetic field can be generated in the shock upstream via the streaming (Weibel-type) instability. Here we develop a self-similar model of the foreshock region and calculate its structure, e.g., the magnetic field strength, its coherence scale, etc., as a function of the distance from the shock. Our model indicates that the entire foreshock region of thickness ∼R/(2Γ 2 sh ), being comparable to the shock radius in the late afterglow phase when Γ sh ∼ 1, can be populated with large-scale and rather strong magnetic fields (of subgauss strengths with the coherence length of order 10 16 cm) compared with the typical interstellar medium magnetic fields. The presence of such fields in the foreshock region is important for high efficiency of Fermi acceleration at the shock. Radiation from accelerated electrons in the foreshock fields can constitute a separate emission region radiating in the UV/optical through radio band, depending on time and shock parameters. We also speculate that these fields being eventually transported into the shock downstream can greatly increase radiative efficiency of a gamma-ray burst afterglow shock.

  9. Simulation of pulsed dielectric barrier discharge xenon excimer lamp

    International Nuclear Information System (INIS)

    Bogdanov, E A; Kudryavtsev, A A; Arslanbekov, R R; Kolobov, V I

    2004-01-01

    Recently, it has been shown that the efficiency of excimer lamps can be drastically increased in a pulsed regime. A one-dimensional simulation of pulsed excimer lamps has been performed by Carman and Mildren (2003 J. Phys. D: Appl. Phys. 36 19) (C and M). However, some computational results of the work of C and M are questionable and need to be revisited. In this paper, a dielectric barrier discharge (DBD) in xenon has been simulated for operating conditions similar to those of C and M to better understand plasma dynamics in a pulsed regime. Our simulation results differ considerably from the computational results of C and M. Although these differences do not affect profoundly the plasma macro parameters measured in the C and M experiments, they offer a better understanding of plasma dynamics in pulsed DBDs and form a solid foundation for computational optimization of excimer lamps. It was found that the dynamics of breakdown and the current pulse depend significantly on the initial densities of species after a previous pulse, and so it is important to accurately simulate the plasma evolution in both the afterglow and active stages. It seems possible to modify the power deposition in the plasma by varying external discharge parameters such as the amplitude and the rise time of the applied voltage, and to modify the plasma composition by changing the pulse repetition rate and plasma decay in the afterglow stage

  10. The metallicity and dust content of a redshift 5 gamma-ray burst host galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Sparre, M.; Krühler, T.; Fynbo, J. P. U.; Watson, D. J.; De Ugarte Postigo, A.; Hjorth, J.; Malesani, D. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark); Hartoog, O. E.; Kaper, L. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands); Wiersema, K. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); D' Elia, V. [INAF/Rome Astronomical Observatory, via Frascati 33, I-00040 Monteporzio Catone (Roma) (Italy); Zafar, T. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Afonso, P. M. J. [Physics and Astronomy Department, American River College, 4700 College Oak Drive, Sacramento, CA 95841 (United States); Covino, S. [INAF, Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy); Flores, H. [Laboratoire GEPI, Observatoire de Paris, CNRS-UMR8111, Universite Paris Diderot 5 place Jules Janssen, F-92195 Meudon (France); Goldoni, P. [APC, Astroparticule et Cosmologie, Universite Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cité, 10, Rue Alice Domon et Léonie Duquet, F-75205 Paris, Cedex 13 (France); Greiner, J. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, IS-107 Reykjavik (Iceland); Klose, S. [Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg (Germany); Levan, A. J., E-mail: sparre@dark-cosmology.dk [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); and others

    2014-04-20

    Observations of the afterglows of long gamma-ray bursts (GRBs) allow the study of star-forming galaxies across most of cosmic history. Here we present observations of GRB 111008A, from which we can measure metallicity, chemical abundance patterns, dust-to-metals ratio (DTM), and extinction of the GRB host galaxy at z = 5.0. The host absorption system is a damped Lyα absorber with a very large neutral hydrogen column density of log N(H I)/cm{sup −2}=22.30±0.06 and a metallicity of [S/H] = –1.70 ± 0.10. It is the highest-redshift GRB with such a precise metallicity measurement. The presence of fine-structure lines confirms the z = 5.0 system as the GRB host galaxy and makes this the highest redshift where Fe II fine-structure lines have been detected. The afterglow is mildly reddened with A{sub V} = 0.11 ± 0.04 mag, and the host galaxy has a DTM that is consistent with being equal to or lower than typical values in the Local Group.

  11. The Zone of Avoidance as an X-ray absorber - the role of the galactic foreground modelling Swift XRT spectra

    Science.gov (United States)

    Racz, I. I.; Bagoly, Z.; Tóth, L. V.; Balázs, L. G.; Horvath, I.; Zahorecz, S.

    2018-05-01

    Gamma-ray bursts (GRBs) are the most powerful explosive events in the Universe. The prompt gamma emission is followed by an X-ray afterglow that is also detected for over nine hundred GRBs by the Swift BAT and XRT detectors. The X-ray afterglow spectrum bears essential information about the burst, and the surrounding interstellar medium (ISM). Since the radiation travels through the line of sight intergalactic medium and the ISM in the Milky Way, the observed emission is influenced by extragalactic and galactic components. The column density of the Galactic foreground ranges several orders of magnitudes, due to both the large scale distribution of ISM and its small scale structures. We examined the effect of local HI column density on the penetrating X-ray emission, as the first step towards a precise modeling of the measured X-ray spectra. We fitted the X-ray spectra using the Xspec software, and checked how the shape of the initially power low spectrum changes with varying input Galactic HI column density. The total absorbing HI column is a sum of the intrinsic and Galactic component. We also investigated the model results for the intrinsic component varying the Galactic foreground. We found that such variations may alter the intrinsic hydrogen column density up to twenty-five percent. We will briefly discuss its consequences.

  12. A gamma-ray burst with a high-energy spectral component inconsistent with the synchrotron shock model.

    Science.gov (United States)

    González, M M; Dingus, B L; Kaneko, Y; Preece, R D; Dermer, C D; Briggs, M S

    2003-08-14

    Gamma-ray bursts are among the most powerful events in nature. These events release most of their energy as photons with energies in the range from 30 keV to a few MeV, with a smaller fraction of the energy radiated in radio, optical, and soft X-ray afterglows. The data are in general agreement with a relativistic shock model, where the prompt and afterglow emissions correspond to synchrotron radiation from shock-accelerated electrons. Here we report an observation of a high-energy (multi-MeV) spectral component in the burst of 17 October 1994 that is distinct from the previously observed lower-energy gamma-ray component. The flux of the high-energy component decays more slowly and its fluence is greater than the lower-energy component; it is described by a power law of differential photon number index approximately -1 up to about 200 MeV. This observation is difficult to explain with the standard synchrotron shock model, suggesting the presence of new phenomena such as a different non-thermal electron process, or the interaction of relativistic protons with photons at the source.

  13. GRB 110205A: ANATOMY OF A LONG GAMMA-RAY BURST

    International Nuclear Information System (INIS)

    Gendre, B.; Stratta, G.; Atteia, J. L.; Klotz, A.; Boër, M.; Colas, F.; Vachier, F.; Kugel, F.; Rinner, C.; Laas-Bourez, M.; Strajnic, J.

    2012-01-01

    The Swift burst GRB 110205A was a very bright burst visible in the Northern Hemisphere. GRB 110205A was intrinsically long and very energetic and it occurred in a low-density interstellar medium environment, leading to delayed afterglow emission and a clear temporal separation of the main emitting components: prompt emission, reverse shock, and forward shock. Our observations show several remarkable features of GRB 110205A: the detection of prompt optical emission strongly correlated with the Burst Alert Telescope light curve, with no temporal lag between the two; the absence of correlation of the X-ray emission compared to the optical and high-energy gamma-ray ones during the prompt phase; and a large optical re-brightening after the end of the prompt phase, that we interpret as a signature of the reverse shock. Beyond the pedagogical value offered by the excellent multi-wavelength coverage of a gamma-ray burst with temporally separated radiating components, we discuss several questions raised by our observations: the nature of the prompt optical emission and the spectral evolution of the prompt emission at high energies (from 0.5 keV to 150 keV); the origin of an X-ray flare at the beginning of the forward shock; and the modeling of the afterglow, including the reverse shock, in the framework of the classical fireball model.

  14. Polarization of the prompt gamma-ray emission from the gamma-ray burst of 6 December 2002.

    Science.gov (United States)

    Coburn, Wayne; Boggs, Steven E

    2003-05-22

    Observations of the afterglows of gamma-ray bursts (GRBs) have revealed that they lie at cosmological distances, and so correspond to the release of an enormous amount of energy. The nature of the central engine that powers these events and the prompt gamma-ray emission mechanism itself remain enigmatic because, once a relativistic fireball is created, the physics of the afterglow is insensitive to the nature of the progenitor. Here we report the discovery of linear polarization in the prompt gamma-ray emission from GRB021206, which indicates that it is synchrotron emission from relativistic electrons in a strong magnetic field. The polarization is at the theoretical maximum, which requires a uniform, large-scale magnetic field over the gamma-ray emission region. A large-scale magnetic field constrains possible progenitors to those either having or producing organized fields. We suggest that the large magnetic energy densities in the progenitor environment (comparable to the kinetic energy densities of the fireball), combined with the large-scale structure of the field, indicate that magnetic fields drive the GRB explosion.

  15. Gamma-ray bursts and their use as cosmic probes

    Science.gov (United States)

    2017-01-01

    Since the launch of the highly successful and ongoing Swift mission, the field of gamma-ray bursts (GRBs) has undergone a revolution. The arcsecond GRB localizations available within just a few minutes of the GRB alert has signified the continual sampling of the GRB evolution through the prompt to afterglow phases revealing unexpected flaring and plateau phases, the first detection of a kilonova coincident with a short GRB, and the identification of samples of low-luminosity, ultra-long and highly dust-extinguished GRBs. The increased numbers of GRB afterglows, GRB-supernova detections, redshifts and host galaxy associations has greatly improved our understanding of what produces and powers these immense, cosmological explosions. Nevertheless, more high-quality data often also reveal greater complexity. In this review, I summarize some of the milestones made in GRB research during the Swift era, and how previous widely accepted theoretical models have had to adapt to accommodate the new wealth of observational data. PMID:28791158

  16. A very energetic supernova associated with the gamma-ray burst of 29 March 2003.

    Science.gov (United States)

    Hjorth, Jens; Sollerman, Jesper; Møller, Palle; Fynbo, Johan P U; Woosley, Stan E; Kouveliotou, Chryssa; Tanvir, Nial R; Greiner, Jochen; Andersen, Michael I; Castro-Tirado, Alberto J; Castro Cerón, José María; Fruchter, Andrew S; Gorosabel, Javier; Jakobsson, Páll; Kaper, Lex; Klose, Sylvio; Masetti, Nicola; Pedersen, Holger; Pedersen, Kristian; Pian, Elena; Palazzi, Eliana; Rhoads, James E; Rol, Evert; van den Heuvel, Edward P J; Vreeswijk, Paul M; Watson, Darach; Wijers, Ralph A M J

    2003-06-19

    Over the past five years evidence has mounted that long-duration (>2 s) gamma-ray bursts (GRBs)-the most luminous of all astronomical explosions-signal the collapse of massive stars in our Universe. This evidence was originally based on the probable association of one unusual GRB with a supernova, but now includes the association of GRBs with regions of massive star formation in distant galaxies, the appearance of supernova-like 'bumps' in the optical afterglow light curves of several bursts and lines of freshly synthesized elements in the spectra of a few X-ray afterglows. These observations support, but do not yet conclusively demonstrate, the idea that long-duration GRBs are associated with the deaths of massive stars, presumably arising from core collapse. Here we report evidence that a very energetic supernova (a hypernova) was temporally and spatially coincident with a GRB at redshift z = 0.1685. The timing of the supernova indicates that it exploded within a few days of the GRB, strongly suggesting that core-collapse events can give rise to GRBs, thereby favouring the 'collapsar' model.

  17. The sub-energetic gamma-ray burst GRB 031203 as a cosmic analogue to the nearby GRB 980425.

    Science.gov (United States)

    Soderberg, A M; Kulkarni, S R; Berger, E; Fox, D W; Sako, M; Frail, D A; Gal-Yam, A; Moon, D S; Cenko, S B; Yost, S A; Phillips, M M; Persson, S E; Freedman, W L; Wyatt, P; Jayawardhana, R; Paulson, D

    2004-08-05

    Over the six years since the discovery of the gamma-ray burst GRB 980425, which was associated with the nearby (distance approximately 40 Mpc) supernova 1998bw, astronomers have debated fiercely the nature of this event. Relative to bursts located at cosmological distance (redshift z approximately 1), GRB 980425 was under-luminous in gamma-rays by three orders of magnitude. Radio calorimetry showed that the explosion was sub-energetic by a factor of 10. Here we report observations of the radio and X-ray afterglow of the recent GRB 031203 (refs 5-7), which has a redshift of z = 0.105. We demonstrate that it too is sub-energetic which, when taken together with the low gamma-ray luminosity, suggests that GRB 031203 is the first cosmic analogue to GRB 980425. We find no evidence that this event was a highly collimated explosion viewed off-axis. Like GRB 980425, GRB 031203 appears to be an intrinsically sub-energetic gamma-ray burst. Such sub-energetic events have faint afterglows. We expect intensive follow-up of faint bursts with smooth gamma-ray light curves (common to both GRB 031203 and 980425) to reveal a large population of such events.

  18. The diverse broad-band light-curves of Swift GRBs reproduced with the cannonball model

    CERN Document Server

    Dado, Shlomo; De Rújula, A

    2009-01-01

    Two radiation mechanisms, inverse Compton scattering (ICS) and synchrotron radiation (SR), suffice within the cannonball (CB) model of long gamma ray bursts (LGRBs) and X-ray flashes (XRFs) to provide a very simple and accurate description of their observed prompt emission and afterglows. Simple as they are, the two mechanisms and the burst environment generate the rich structure of the light curves at all frequencies and times. This is demonstrated for 33 selected Swift LGRBs and XRFs, which are well sampled from early time until late time and well represent the entire diversity of the broad band light curves of Swift LGRBs and XRFs. Their prompt gamma-ray and X-ray emission is dominated by ICS of glory light. During their fast decline phase, ICS is taken over by SR which dominates their broad band afterglow. The pulse shape and spectral evolution of the gamma-ray peaks and the early-time X-ray flares, and even the delayed optical `humps' in XRFs, are correctly predicted. The canonical and non-canonical X-ra...

  19. An origin for short gamma-ray bursts unassociated with current star formation.

    Science.gov (United States)

    Barthelmy, S D; Chincarini, G; Burrows, D N; Gehrels, N; Covino, S; Moretti, A; Romano, P; O'Brien, P T; Sarazin, C L; Kouveliotou, C; Goad, M; Vaughan, S; Tagliaferri, G; Zhang, B; Antonelli, L A; Campana, S; Cummings, J R; D'Avanzo, P; Davies, M B; Giommi, P; Grupe, D; Kaneko, Y; Kennea, J A; King, A; Kobayashi, S; Melandri, A; Meszaros, P; Nousek, J A; Patel, S; Sakamoto, T; Wijers, R A M J

    2005-12-15

    Two short (gamma-ray bursts (GRBs) have recently been localized and fading afterglow counterparts detected. The combination of these two results left unclear the nature of the host galaxies of the bursts, because one was a star-forming dwarf, while the other was probably an elliptical galaxy. Here we report the X-ray localization of a short burst (GRB 050724) with unusual gamma-ray and X-ray properties. The X-ray afterglow lies off the centre of an elliptical galaxy at a redshift of z = 0.258 (ref. 5), coincident with the position determined by ground-based optical and radio observations. The low level of star formation typical for elliptical galaxies makes it unlikely that the burst originated in a supernova explosion. A supernova origin was also ruled out for GRB 050709 (refs 3, 31), even though that burst took place in a galaxy with current star formation. The isotropic energy for the short bursts is 2-3 orders of magnitude lower than that for the long bursts. Our results therefore suggest that an alternative source of bursts--the coalescence of binary systems of neutron stars or a neutron star-black hole pair--are the progenitors of short bursts.

  20. ESTIMATING LONG GRB JET OPENING ANGLES AND REST-FRAME ENERGETICS

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, Adam [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Connaughton, Valerie [Science and Technology Institute, Universities Space Research Association, Huntsville, AL 35805 (United States); Briggs, Michael S.; Burns, Eric, E-mail: adam.m.goldstein@nasa.gov [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States)

    2016-02-10

    We present a method to estimate the jet opening angles of long duration gamma-ray bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the time-integrated peak energy of the GRB prompt spectrum and the collimation-corrected energy in gamma-rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate the probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies.