WorldWideScience

Sample records for superluminal source grs

  1. Infrared spectroscopy of the superluminal Galactic source GRS 1915+105 during the 1994 September outburst

    DEFF Research Database (Denmark)

    CastroTirado, A.J.; Geballe, T.R.; Lund, Niels

    1996-01-01

    We have obtained K-band IR spectra of the superluminal Galactic source GRS 1915+105 on two different dates. The second spectrum, obtained immediately after a bright X-ray outburst in 1994 September, has shown prominent H and He emission lines. The lines are not Doppler shifted, as are those obser...

  2. On the Lorentz Factor of Superluminal Sources

    CERN Document Server

    Onuchukwu, Chika Christian

    2013-01-01

    We investigate the properties of features seen within superluminal sources often referred to as components. Our result indicates a fairly strong correlation of r=0.6 for quasars, r=0.4 for galaxies, and r=0.8 for BL Lac objects in our sample between component sizes and distances from the stationary core. Assumption of free adiabatic expanding plasma enabled us to constrain in general the Lorentz factor for superluminal sources. Ourestimated Lorentz factor of 7 - 17 for quasars, 6 - 13 for galaxies and 4- 9 for BL Lac objects indicate that BL Lac have the lowest range of Lorentz factor.

  3. On the Lorentz factor of superluminal sources

    Institute of Scientific and Technical Information of China (English)

    Chika Christian Onuchukwu; Augustine A.Ubachukwu

    2013-01-01

    We investigate the properties of features seen within superluminal sources often referred to as components.Our result indicates a fairly strong correlation of r ~ 0.5 for quasars,r ~ 0.4 for galaxies and r ~ 0.7 for BL Lac objects in our sample between component sizes and distances from the stationary core.The assumption of free adiabatic expanding plasma enables us to constrain the Lorentz factor for superluminal sources.Our estimated Lorentz factor of γ ~ 9-13 for quasars,γ ~ 7-11for galaxies and γ ~ 4-9 for BL Lac objects indicates that BL Lacs have the lowest range of Lorentz factors.

  4. Observation of image pair creation and annihilation from superluminal scattering sources

    CERN Document Server

    Clerici, Matteo; Warburton, Ryan E; Lyons, Ashley; Aniculaesei, Constantin; Richards, Joseph M; Leach, Jonathan; Henderson, Robert; Faccio, Daniele

    2015-01-01

    The invariance of the speed of light implies a series of consequences related to our perception of simultaneity and of time itself. Whilst these consequences are experimentally well studied for subluminal speeds, the kinematics of superluminal motion lack direct evidence. Using high temporal resolution imaging techniques, we demonstrate that if a source approaches an observer at superluminal speeds, the temporal ordering of events is inverted and its image appears to propagate backwards. If the source changes its speed, crossing the interface between sub- and super-luminal propagation, we observe image pair annihilation and creation. These results show that it is not possible to unambiguously determine the kinematics of an event from imaging and time-resolved measurements alone.

  5. Observation of image pair creation and annihilation from superluminal scattering sources.

    Science.gov (United States)

    Clerici, Matteo; Spalding, Gabriel C; Warburton, Ryan; Lyons, Ashley; Aniculaesei, Constantin; Richards, Joseph M; Leach, Jonathan; Henderson, Robert; Faccio, Daniele

    2016-04-01

    The invariance of the speed of light is one of the foundational pillars of our current understanding of the universe. It implies a series of consequences related to our perception of simultaneity and, ultimately, of time itself. Whereas these consequences are experimentally well studied in the case of subluminal motion, the kinematics of superluminal motion lack direct evidence or even a clear experimental approach. We investigate kinematic effects associated with the superluminal motion of a light source. By using high-temporal-resolution imaging techniques, we directly demonstrate that if the source approaches an observer at superluminal speeds, the temporal ordering of events is inverted and its image appears to propagate backward. Moreover, for a source changing its speed and crossing the interface between subluminal and superluminal propagation regions, we observe image pair annihilation and creation, depending on the crossing direction. These results are very general and show that, regardless of the emitter speed, it is not possible to unambiguously determine the kinematics of an event from imaging and time-resolved measurements alone. This has implications not only for light, but also, for example, for sound and other wave phenomena.

  6. The superluminal radio source 4c 39. 25 as relativistic jet prototype. El cuasar superluminal 4C 93. 25 como prototipo de jet relativistia

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, A.; Gomez, J.L.; Marcaide, J.M.

    1993-01-01

    We have developed a numerical code which solves the synchrotron radiation transfer equations to compute the total and polarized emission of bent shocked relativistic jets, and we have applied it to reproduce the compact structure, kinematic evolution of the superluminal radio source 4C 39.25 contains a bent relativistic jet which is misaligned relative to the observer near the core region, leading to a relatively low core brightness. (Author) 12 refs.

  7. Superluminal motion in a compact steep spectrum radio source 3C 138

    CERN Document Server

    Shen, Z Q; Kameno, S; Chen, Y J

    2001-01-01

    We present the results of 5 GHz VLBI observations of a compact steep spectrum source 3C 138. The data are consistent with the western end being the location of the central activity. The observed offset between different frequencies in the central region of 3C 138 can be accounted for by a frequency dependent shift of the synchrotron self-absorbed core. Our new measurements confirm the existence of a superluminal motion, but its apparent velocity of 3.3c is three times slower than the reported one. This value is consistent with the absence of parsec-scale counter-jet emission in the inner region, but seems still too high to allow the overall counter-jet to be seen in terms of Doppler boosting of an intrinsically identical jet. Either an interaction of jet with central dense medium, or an intrinsically asymmetrical jet must be invoked to reconcile the detected superluminal speed with the observed large scale asymmetry in 3C 138.

  8. 3D Simulations of Relativistic Precessing Jets Probing the Structure of Superluminal Sources

    CERN Document Server

    Aloy, M A; Gómez, J L; Agudo, I; Müller, E; Ibanyez, J M; Aloy, Miguel Angel; Marti, Jose Maria; Gomez, Jose Luis; Agudo, Ivan; Mueller, Ewald; Ibanyez, Jose Maria

    2003-01-01

    We present the results of a three-dimensional, relativistic, hydrodynamic simulation of a precessing jet into which a compact blob of matter is injected. A comparison of synthetic radio maps computed from the hydrodynamic model, taking into account the appropriate light travel time delays, with those obtained from observations of actual superluminal sources shows that the variability of the jet emission is the result of a complex combination of phase motions, viewing angle selection effects, and non-linear interactions between perturbations and the underlying jet and/or the external medium. These results question the hydrodynamic properties inferred from observed apparent motions and radio structures, and reveal that shock-in-jet models may be overly simplistic.

  9. The discovery and preliminary results of observations of the transient X-ray source GRS 0834 - 43 with the Watch instrument of the GRANAT observatory

    DEFF Research Database (Denmark)

    Lapshov, I. Yu.; Dremin, V. V.; Syunyaev, R. A.;

    1992-01-01

    The history of discovery and localization of the GRS 0834-430 source with the Watch instrument on Granat is described. The Light curve of this source for the period January 1990-October 1991 is presented. Outbursts with a period of 114 days are discussed......The history of discovery and localization of the GRS 0834-430 source with the Watch instrument on Granat is described. The Light curve of this source for the period January 1990-October 1991 is presented. Outbursts with a period of 114 days are discussed...

  10. A Triple-energy-source Model for Superluminous Supernova iPTF13ehe

    Science.gov (United States)

    Wang, S. Q.; Liu, L. D.; Dai, Z. G.; Wang, L. J.; Wu, X. F.

    2016-09-01

    Almost all superluminous supernovae (SLSNe) whose peak magnitudes are ≲ -21 mag can be explained by the 56Ni-powered model, the magnetar-powered (highly magnetized pulsar) model, or the ejecta-circumstellar medium (CSM) interaction model. Recently, iPTF13ehe challenged these energy-source models, because the spectral analysis shows that ˜ 2.5{M}⊙ of 56Ni have been synthesized, but are inadequate to power the peak bolometric emission of iPTF13ehe, while the rebrightening of the late-time light curve (LC) and the Hα emission lines indicate that the ejecta-CSM interaction must play a key role in powering the late-time LC. Here we propose a triple-energy-source model, in which a magnetar together with some amount (≲ 2.5{M}⊙ ) of 56Ni may power the early LC of iPTF13ehe, while the late-time rebrightening can be quantitatively explained by an ejecta-CSM interaction. Furthermore, we suggest that iPTF13ehe is a genuine core-collapse supernova rather than a pulsational pair-instability supernova candidate. Further studies on similar SLSNe in the future would eventually shed light on their explosion and energy-source mechanisms.

  11. X-ray Measurements of Black Hole X-ray Binary Source GRS 1915+105 and the Evolution of Hard X-ray Spectrum

    Indian Academy of Sciences (India)

    R. K. Manchanda

    2000-06-01

    We report the spectral measurement of GRS 1915+105 in the hard X-ray energy band of 20-140keV. The observations were made on March 30th, 1997 during a quiescent phase of the source. We discuss the mechanism of emission of hard X-ray photons and the evolution of the spectrum by comparing the data with earlier measurements and an axiomatic model for the X-ray source.

  12. Superluminal antenna

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, John; Earley, Lawrence M.; Krawczyk, Frank L.; Potter, James M.; Romero, William P.; Wang, Zhi-Fu

    2017-03-28

    A superluminal antenna element integrates a balun element to better impedance match an input cable or waveguide to a dielectric radiator element, thus preventing stray reflections and consequent undesirable radiation. For example, a dielectric housing material can be used that has a cutout area. A cable can extend into the cutout area. A triangular conductor can function as an impedance transition. An additional cylindrical element functions as a sleeve balun to better impedance match the radiator element to the cable.

  13. Superluminality in the Bi- and Multi Galileon

    CERN Document Server

    de Fromont, Paul; Heisenberg, Lavinia; Matas, Andrew

    2013-01-01

    We re-explore the Bi- and Multi-Galileon models with trivial asymptotic conditions at infinity and show that propagation of superluminal fluctuations is a common and unavoidable feature of these theories, unlike previously claimed in the literature. We show that all Multi-Galileon theories containing a Cubic Galileon term exhibit superluminalities at large distances from a point source, and that even if the Cubic Galileon is not present one can always find sensible matter distributions in which there are superluminal modes at large distances. In the Bi-Galileon case we explicitly show that there are always superluminal modes around a point source even if the Cubic Galileon is not present. Finally, we briefly comment on the possibility of avoiding superluminalities by modifying the asymptotic conditions at infinity.

  14. Relativistic jet with shock waves like model of superluminal radio source. Jet relativista con ondas de choque como modelo de radio fuentes superluminales

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, A.; Gomez, J.L.; Marcaide, J.M.

    1993-01-01

    The structure of the compact radio sources at milliarcsecond angular resolution can be explained in terms of shock waves propagating along bent jets. These jets consist of narrow-angle cones of plasma flowing at bulk relativistic velocities, within tangled magnetic fields, emitting synchrotron radiation. We have developed a numerical code which solves the synchrotron radiation transfer equations to compute the total and polarized emission of bent shocked relativistic jets, and we have applied it to reproduce the compact structure, kenimatic evolution and time flux density evolution of the superluminal radio source 4C 39.25 and to obtain its jet physical parameters. (Author) 23 ref.

  15. Anti-correlated hard X-ray time lag in GRS 1915+105: evidence for a truncated accretion disc

    CERN Document Server

    Choudhury, M; Das-Gupta, S; Pendharkar, J; Sriram, K; Agrawal, V K; Choudhury, Manojendu; Dasgupta, Surajit

    2005-01-01

    Multi-wavelength observations of Galactic black hole candidate sources indicate a close connection between the accretion disk emission and the jet emission. The recent discovery of an anti-correlated time lag between the soft and hard X-rays in Cygnus X-3 (Choudhury & Rao 2004) constrains the geometric picture of the disk-jet connection into a truncated accretion disk, the truncation radius being quite close to the black hole. Here we report the detection of similar anti-correlated time lag in the superluminal jet source GRS 1915+105. We show the existence of the pivoting in the X-ray spectrum during the delayed anti-correlation and we also find that the QPO parameters change along with the spectral pivoting. We explore theoretical models to understand this phenomenon.

  16. Superluminal Motion Found In Milky Way

    Science.gov (United States)

    1994-08-01

    subatomic particles from its poles, and it is in these jets that the rapidly-moving material was tracked. The object, known as GRS 1915+105, also is a strong emitter of X-Rays, sometimes becoming the strongest source of X-Rays in the Milky Way. The X-rays, they think, are emitted from the system's accretion disk. The VLA observations, along with other evidence the researchers have uncovered, leads them to believe that, despite being much less massive than galactic cores, other double-star systems may be capable of ejecting material at speeds near that of light. The researchers reported their discovery in the September 1 issue of the journal Nature. "This discovery is one of the most valuable results of more than a decade and a half of observations at the VLA," said Dr. Miller Goss, assistant director of NRAO for VLA/VLBA operations. "We see these fast-moving jets of material throughout the universe, and they represent an important physical process. However, they're usually so far away that it's difficult to study them. This object, relatively nearby, offers the best opportunity yet to build a good understanding of how such jets actually work," Goss added. GRS 1915+105 was discovered in 1992 by an orbiting French- Russian X-ray observatory called SIGMA-GRANAT. It had not been found before because its X-rays are highly-energetic "hard" X-rays not regularly observed by satellites before then. Since its discovery, it has repeatedly been seen as a source of "hard" X- rays. Despite searching, the scientists have been unable to observe the object in visible light. Observations with the VLA in 1992 and 1993 showed that the object changed both its radio "brightness" and its apparent position in the sky, but it was then too faint at radio wavelengths for precise measurements. In March of 1994, the object began an outburst of strong radio emission just as the VLA had entered a configuration capable of its most precise positional measurements. Through March and April of 1994, Mirabel

  17. Superluminal neutrinos and quantum cross-correlation theory of neutrino source location

    CERN Document Server

    Rusov, V D; Tarasov, V A; Sharph, I V; Smolyar, V P; Zelentsova, T N; Merkotan, K K; Linnik, E P; Beglaryan, M E

    2012-01-01

    Based on the developed cross-correlation theory for remote location of neutrino source with two-detector setup for neutrino detection the modification of arrangement of the OPERA experiment is suggested. Within the framework of computing experiment based on the OPERA experimental data we show that the use of this theory makes it possible not only to determine with high accuracy the delay time between neutrino signals but to eliminate the errors of blind analysis by which all necessary time corrections for determination of signal "technologically unremovable" delay time between CERN and GSL are performed.

  18. First INTEGRAL observations of GRS 1915+105

    DEFF Research Database (Denmark)

    Hannikainen, D.C.; Vilhu, O.; Rodriguez, J.

    2003-01-01

    We present data from the first of six monitoring Open Time observations of GRS 1915+105 undertaken with the orbiting INTEGRAL satellite. The source was clearly detected with all three X-ray and gamma-ray instruments on board. GRS 1915+105 was in a highly variable state, as demonstrated by the JEMX...

  19. Great Red Spot (GRS)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    A huge permanent anticyclone in Jupiter's southern hemisphere, visible as a reddish oval at just over 20 °S. The earliest unequivocal observation was by Heinrich Schwabe in 1831 (the often-quoted sighting by Robert Hooke in 1664 now seems to have been of a similar but different spot). The GRS became a striking feature around 1880, when it developed a deep red coloration. It was also prominent in ...

  20. TOUGH2-GRS version 1. User manual

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Martin; Eckel, Jens

    2016-07-15

    TOUGH2 is a code for the simulation of multi-phase flow processes in porous media that has been developed by the Lawrence Berkeley National Laboratory, California, USA. Since 1991, GRS has been using the code for process analyses and safety assessments for deep geological repositories and has extended the code by several processes that are relevant for repository systems. The TOUGH2 source code that has been developed further by GRS is referred to as TOUGH2-GRS. The present report presents code version 1.1.g, which was developed in project UM13 A 03400 sponsored by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB).

  1. Superluminality in the Bi- and Multi-Galileon

    Science.gov (United States)

    de Fromont, Paul; de Rham, Claudia; Heisenberg, Lavinia; Matas, Andrew

    2013-07-01

    We re-explore the Bi- and Multi-Galileon models with trivial asymptotic conditions at infinity and show that propagation of superluminal fluctuations is a common and unavoidable feature of these theories, unlike previously claimed in the literature. We show that all Multi-Galileon theories containing a Cubic Galileon term exhibit superluminalities at large distances from a point source, and that even if the Cubic Galileon is not present one can always find sensible matter distributions in which there are superluminal modes at large distances. In the Bi-Galileon case we explicitly show that there are always superluminal modes around a point source even if the Cubic Galileon is not present. Finally, we briefly comment on the possibility of avoiding superluminalities by modifying the asymptotic conditions at infinity.

  2. The Shape of Superluminous Supernovae

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    What causes the tremendous explosions of superluminous supernovae? New observations reveal the geometry of one such explosion, SN 2015bn, providing clues as to its source.A New Class of ExplosionsImage of a type Ia supernova in the galaxy NGC 4526. [NASA/ESA]Supernovae are powerful explosions that can briefly outshine the galaxies that host them. There are several different classifications of supernovae, each with a different physical source such as thermonuclear instability in a white dwarf, caused by accretion of too much mass, or the exhaustion of fuel in the core of a massive star, leading to the cores collapse and expulsion of its outer layers.In recent years, however, weve detected another type of supernovae, referred to as superluminous supernovae. These particularly energetic explosions last longer months instead of weeks and are brighter at their peaks than normal supernovae by factors of tens to hundreds.The physical cause of these unusual explosions is still a topic of debate. Recently, however, a team of scientists led by Cosimo Inserra (Queens University Belfast) has obtained new observations of a superluminous supernova that might help address this question.The flux and the polarization level (black lines) along the dominant axis of SN 2015bn, 24 days before peak flux (left) and 28 days after peak flux (right). Blue lines show the authors best-fitting model. [Inserra et al. 2016]Probing GeometryInserra and collaborators obtained two sets of observations of SN 2015bn one roughly a month before and one a month after the superluminous supernovas peak brightness using a spectrograph on the Very Large Telescope in Chile. These observations mark the first spectropolarimetric data for a superluminous supernova.Spectropolarimetry is the practice of obtaining information about the polarization of radiation from an objects spectrum. Polarization carries information about broken spatial symmetries in the object: only if the object is perfectly symmetric can it

  3. Nonlinearity without Superluminality

    CERN Document Server

    Kent, A

    2002-01-01

    Quantum theory is compatible with special relativity. In particular, though measurements on entangled systems are correlated in a way that cannot be reproduced by local hidden variables, they cannot be used for superluminal signalling. As Gisin and Polchinski first pointed out, this is not true for general nonlinear modifications of the Schroedinger equation. Excluding superluminal signalling has thus been taken to rule out most nonlinear versions of quantum theory. The no superluminal signalling constraint has also been used for alternative derivations of the optimal fidelities attainable for imperfect quantum cloning and other operations. These results apply to theories satisfying the rule that their predictions for widely separated and slowly moving entangled systems can be approximated by non-relativistic equations of motion with respect to a preferred time coordinate. This paper describes a natural way in which this rule might fail to hold. In particular, it is shown that quantum readout devices which di...

  4. Cosmology with Superluminous Supernovae

    CERN Document Server

    Scovacricchi, Dario; Bacon, David; Sullivan, Mark; Prajs, Szymon

    2015-01-01

    We predict cosmological constraints for forthcoming surveys using Superluminous Supernovae (SLSNe) as standardisable candles. Due to their high peak luminosity, these events can be observed to high redshift (z~3), opening up new possibilities to probe the Universe in the deceleration epoch. We describe our methodology for creating mock Hubble diagrams for the Dark Energy Survey (DES), the "Search Using DECam for Superluminous Supernovae" (SUDSS) and a sample of SLSNe possible from the Large Synoptic Survey Telescope (LSST), exploring a range of standardisation values for SLSNe. We include uncertainties due to gravitational lensing and marginalise over possible uncertainties in the magnitude scale of the observations (e.g. uncertain absolute peak magnitude, calibration errors). We find that the addition of only ~100 SLSNe from SUDSS to 3800 Type Ia Supernovae (SNe Ia) from DES can improve the constraints on w and Omega_m by at least 20% (assuming a flat wCDM universe). Moreover, the combination of DES SNe Ia a...

  5. Superluminal Recession Velocities

    CERN Document Server

    Davis, T M; Davis, Tamara M.; Lineweaver, Charles H.

    2000-01-01

    Hubble's Law, v=HD (recession velocity is proportional to distance), is a theoretical result derived from the Friedmann-Robertson-Walker metric. v=HD applies at least as far as the particle horizon and in principle for all distances. Thus, galaxies with distances greater than D=c/H are receding from us with velocities greater than the speed of light and superluminal recession is a fundamental part of the general relativistic description of the expanding universe. This apparent contradiction of special relativity (SR) is often mistakenly remedied by converting redshift to velocity using SR. Here we show that galaxies with recession velocities faster than the speed of light are observable and that in all viable cosmological models, galaxies above a redshift of three are receding superluminally.

  6. Superluminal Black Holes

    CERN Document Server

    Dolgov, D S

    1993-01-01

    The new solution of the Einstein equations in empty space is presented. The solution is constructed using Schwarzschild solution but essentially differs from it. The basic properties of the solution are: the existence of a horizon which is a hyperboloid of one sheet moving along its axis with superluminal velocity, right signature of the metric outside the horizon and Minkovsky-flatness of it at infinity outside the horizon. There is also a discussion in the last chapter, including comparing with recent astronomical observations.

  7. Superluminality and UV Completion

    CERN Document Server

    Shore, G M

    2007-01-01

    The idea that the existence of a consistent UV completion satisfying the fundamental axioms of local quantum field theory or string theory may impose positivity constraints on the couplings of the leading irrelevant operators in a low-energy effective field theory is critically discussed. Violation of these constraints implies superluminal propagation, in the sense that the low-frequency limit of the phase velocity $v_{\\rm ph}(0)$ exceeds $c$. It is explained why causality is related not to $v_{\\rm ph}(0)$ but to the high-frequency limit $v_{\\rm ph}(\\infty)$ and how these are related by the Kramers-Kronig dispersion relation, depending on the sign of the imaginary part of the refractive index $\\Ima n(\\w)$ which is normally assumed positive. Superluminal propagation and its relation to UV completion is investigated in detail in three theories: QED in a background electromagnetic field, where the full dispersion relation for $n(\\w)$ is evaluated numerically for the first time and the role of the null energy con...

  8. INTEGRAL observation of GRS 1739-278 in outburst

    DEFF Research Database (Denmark)

    Filippova, E.; Kuulkers, E.; Alfonso-Garzon, J.;

    2014-01-01

    During the Galactic bulge monitoring observation (Atel #438) performed on 2014 March 19 from 11.00 to 14:42 (UTC), the black-hole candidate GRS 1739-278 (ATel #5986) was also seen by INTEGRAL. The source is detected by IBIS/ISGRI up to an energy of about 200 keV. The estimated ISGRI flux is 143...

  9. Statistics of Superluminal Motion in Active Galactic Nuclei

    Institute of Scientific and Technical Information of China (English)

    Yong-Wei Zhang; Jun-Hui Fan

    2008-01-01

    We have collected an up-to-date sample of 123 superluminal sources (84 quasars, 27 BL Lac objects and 12 galaxies) and calculated the apparent velocities (βapp) for 224 components in the sources with the A-CDM model. We checked the relationships between their proper motions, redshifts,βapp and 5 GHz flux densities. Our analysis shows that the radio emission is strongly boosted by the Doppler effect. The superluminal motion and the relativistic beaming boosting effect are, to some extent, the same in active galactic nuclei.

  10. Superluminal Neutrinos and Monopoles

    CERN Document Server

    Wang, Peng; Yang, Haitang

    2011-01-01

    In this letter, we show that superluminal neutrinos announced by OPERA could be explained by the existence of a monopole, which is left behind after the spontaneous symmetry braking (SSB) phase transition of some scalar fields in the universe. We assume the 't Hooft-Polyakov monopole couples to the neutrinos but not photon fields. The monopole causes effective metric to the neutrinos, different from the Minkovski one. We find that the monopoles have influences on neutrinos only within the range about $10^3$ cm. Neutrinos always arrive earlier than photons by the same amount of time, once there exists a monopole on or close to their trajectories. This result reconciles the contradiction between OPERA and supernova neutrinos.

  11. Cosmology with superluminous supernovae

    Science.gov (United States)

    Scovacricchi, D.; Nichol, R. C.; Bacon, D.; Sullivan, M.; Prajs, S.

    2016-02-01

    We predict cosmological constraints for forthcoming surveys using superluminous supernovae (SLSNe) as standardizable candles. Due to their high peak luminosity, these events can be observed to high redshift (z ˜ 3), opening up new possibilities to probe the Universe in the deceleration epoch. We describe our methodology for creating mock Hubble diagrams for the Dark Energy Survey (DES), the `Search Using DECam for Superluminous Supernovae' (SUDSS) and a sample of SLSNe possible from the Large Synoptic Survey Telescope (LSST), exploring a range of standardization values for SLSNe. We include uncertainties due to gravitational lensing and marginalize over possible uncertainties in the magnitude scale of the observations (e.g. uncertain absolute peak magnitude, calibration errors). We find that the addition of only ≃100 SLSNe from SUDSS to 3800 Type Ia Supernovae (SNe Ia) from DES can improve the constraints on w and Ωm by at least 20 per cent (assuming a flat wCDM universe). Moreover, the combination of DES SNe Ia and 10 000 LSST-like SLSNe can measure Ωm and w to 2 and 4 per cent, respectively. The real power of SLSNe becomes evident when we consider possible temporal variations in w(a), giving possible uncertainties of only 2, 5 and 14 per cent on Ωm, w0 and wa, respectively, from the combination of DES SNe Ia, LSST-like SLSNe and Planck. These errors are competitive with predicted Euclid constraints, indicating a future role for SLSNe for probing the high-redshift Universe.

  12. Challenges Confronting Superluminal Neutrino Models

    Science.gov (United States)

    Evslin, Jarah

    2012-12-01

    This talk opens the CosPA2011 session on OPERA's superluminal neutrino claim. I summarize relevant observations and constraints from OPERA, MINOS, ICARUS, KamLAND, IceCube and LEP as well as observations of SN1987A. I selectively review some models of neutrino superluminality which have been proposed since OPERA's announcement, focusing on a neutrino dark energy model. Powerful theoretical constraints on these models arise from Cohen-Glashow bremsstrahlung and from phase space requirements for the initial neutrino production. I discuss these constraints and how they might be evaded in models in which the maximum velocities of both neutrinos and charged leptons are equal but only superluminal inside of a dense medium.

  13. Challenges Confronting Superluminal Neutrino Models

    CERN Document Server

    Evslin, Jarah

    2011-01-01

    This talk opens the CosPA2011 session on OPERA's superluminal neutrino claim. I summarize relevant observations and constraints from OPERA, MINOS, ICARUS, KamLAND, IceCube and LEP as well as observations of SN1987A. I selectively review some models of neutrino superluminality which have been proposed since OPERA's announcement, focusing on a neutrino dark energy model. Powerful theoretical constraints on these models arise from Cohen-Glashow bremsstrahlung and from phase space requirements for the initial neutrino production. I discuss these constraints and how they might be evaded in models in which the maximum velocities of both neutrinos and charged leptons are equal but only superluminal inside of a dense medium.

  14. Superluminal travel requires negative energies

    OpenAIRE

    Olum, Ken D.

    1998-01-01

    I investigate the relationship between faster-than-light travel and weak-energy-condition violation, i.e., negative energy densities. In a general spacetime it is difficult to define faster-than-light travel, and I give an example of a metric which appears to allow superluminal travel, but in fact is just flat space. To avoid such difficulties, I propose a definition of superluminal travel which requires that the path to be traveled reach a destination surface at an earlier time than any neig...

  15. A note on superluminal neutrinos

    Science.gov (United States)

    Cutolo, A.

    2012-05-01

    Although characterized by a possible experimental error, the first results of the Opera experiment at CERN have opened up a hot discussion on the possibility of superluminal neutrinos already observed in some space events. In particular, Cohen and Glashow (CG) have considered it simply an error justifying their position on the basis of the bremsstrahlung of electron-positron pairs. In this paper, we would like to discuss this position also in view of the recent derivation of the superluminal limit as a consequence of the classical causality principle. Even if the final answer is related only to the review of all the experimental results, we believe that neutral particles (neutrinos, photons, etc.) might exhibit superluminal behavior also in view of the fact that the analysis performed by Cohen and Glashow does not contain any absolute limit, like that present in the case of the Cherenkov effect in vacuum, which is absolutely impossible, as its violation would require an infinite energy amount. CG conclusions are not in contrast with superluminal neutrinos, which, in turn, are fully compatible with the theoretical analysis reported as well.

  16. Invisibility cloaking without superluminal propagation

    Energy Technology Data Exchange (ETDEWEB)

    Perczel, Janos; Leonhardt, Ulf [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Tyc, Tomas, E-mail: jp394@st-andrews.ac.uk, E-mail: tomtyc@physics.muni.cz, E-mail: ulf@st-andrews.ac.uk [Faculty of Science, Kotlarska 2 and Faculty of Informatics, Botanicka 68a, Masaryk University, 61137 Brno (Czech Republic)

    2011-08-15

    Conventional cloaking based on Euclidean transformation optics requires that the speed of light should tend to infinity on the inner surface of the cloak. Non-Euclidean cloaking still needs media with superluminal propagation. Here we show by giving an example that this is no longer necessary.

  17. Popper's Experiment and Superluminal Communication

    CERN Document Server

    Gerjuoy, E; Gerjuoy, Edward; Sessler, Andrew M.

    2005-01-01

    We comment on Tabesh Qureshi, "Understanding Popper's Experiment," AJP 73, 541 (June 2005), in particular on the implications of its section IV. We show, in the situation envisaged by Popper, that analysis solely with conventional non-relativistic quantum mechanics suffices to exclude the possibility of superluminal communication.

  18. Probing Superluminal Neutrinos Via Refraction

    OpenAIRE

    Stebbins, Albert

    2011-01-01

    One phenomenological explanation of superluminal propagation of neutrinos, which may have been observed by OPERA and MINOS, is that neutrinos travel faster inside of matter than in vacuum. If so neutrinos exhibit refraction inside matter and should exhibit other manifestations of refraction, such as deflection and reflection. Such refraction would be easily detectable through the momentum imparted to appropriately shaped refractive material inserted into the neutrino beam. For NuMI this could...

  19. Neutrino oscillations and superluminal propagation

    CERN Document Server

    Magueijo, Joao

    2011-01-01

    We digress on the implications of recent claims of superluminal neutrino propagation. No matter how we turn it around such behaviour is very odd and sits uncomfortably even within "far-fetched" theories. In the context of non-linear realizations of the Lorentz group (where superluminal misbehaviour is run of the mill) one has to accept rather contrived constructions to predict superluminal properties for the neutrino. The simplest explanation is to require that at least one of the mass states be tachyonic. We show that due to neutrino mixing, the flavor energy does not suffer from the usual runaway pathologies of tachyons. For non-tachyonic mass states the theories become more speculative. A neutrino specific dispersion relation is exhibited, rendering the amplitude of the effect reasonable for a standard Planck energy. This uses the fact that the beam energy is close to the geometrical average of the neutrino and Planck mass; or, seen in another way, the beam energy is unexceptional but its gamma factor is v...

  20. Relativistic solitons and superluminal signals

    Energy Technology Data Exchange (ETDEWEB)

    Maccari, Attilio [Technical Institute ' G. Cardano' , Piazza della Resistenza 1, Monterotondo, Rome 00015 (Italy)]. E-mail: solitone@yahoo.it

    2005-02-01

    Envelope solitons in the weakly nonlinear Klein-Gordon equation in 1 + 1 dimensions are investigated by the asymptotic perturbation (AP) method. Two different types of solitons are possible according to the properties of the dispersion relation. In the first case, solitons propagate with the group velocity (less than the light speed) of the carrier wave, on the contrary in the second case solitons always move with the group velocity of the carrier wave, but now this velocity is greater than the light speed. Superluminal signals are then possible in classical relativistic nonlinear field equations.

  1. Multi-Epoch Spectroscopy of Hydrogen-Poor Superluminous Supernovae

    Science.gov (United States)

    Quimby, Robert; De Cia, Annalisa; Gal-Yam, Avishay; Leloudas, Giorgos; Lunnan, Ragnhild; Perley, Daniel A.; Vreeswijk, Paul; Yan, Lin

    2016-06-01

    A growing sample of intrinsically rare supernovae is being uncovered by wide-field synoptic surveys, such as the Palomar Transient Factory (PTF). A fraction of these events have been labeled "superluminous supernovae" due to their peak luminosities, which can exceed normal supernovae by factors of 10 to 100. The power sources for these events and thus their connection to normal luminosity supernovae remains uncertain. Here we present results from 134 spectroscopic observations of 17 hydrogen-poor superluminous supernovae (SLSN-I) discovered by PTF. We select our targets from the full PTF sample using only spectroscopic information; we do not employ the traditional cut in absolute magnitude (e.g. M physical insights into the nature of these explosions offered by this unique dataset.

  2. X-Ray Transient in Musca (GRS 1121-68 = GS 1124-683)

    DEFF Research Database (Denmark)

    Lund, Niels; Brandt, Søren; Makino, F.

    1991-01-01

    Research Institute, Lyngby; and Space Research Institute, Moscow), report: "A new x-ray source in Musca, GRS 1121-68, has been discovered in data obtained by the WATCH detectors on Jan. 9. The spectrum of the source was harder than that of the Crab nebula, and the flux was about twice that from...

  3. Torsion pendulum facility for direct force measurements of LISA GRS related disturbances

    CERN Document Server

    Carbone, L; Ciani, G; Dolesi, R; Hüller, M; Tombolato, D; Vitale, S; Weber, W J

    2007-01-01

    A four mass torsion pendulum facility for testing of the LISA GRS is under development in Trento. With a LISA-like test mass suspended off-axis with respect to the pendulum fiber, the facility allows for a direct measurement of surface force disturbances arising in the GRS. We present here results with a prototype pendulum integrated with very large-gap sensors, which allows an estimate of the intrinsic pendulum noise floor in the absence of sensor related force noise. The apparatus has shown a torque noise near to its mechanical thermal noise limit, and would allow to place upper limits on GRS related disturbances with a best sensitivity of 300 fN/Hz^(1/2) at 1mHz, a factor 50 from the LISA goal. Also, we discuss the characterization of the gravity gradient noise, one environmental noise source that could limit the apparatus performances, and report on the status of development of the facility.

  4. Wave Scattering by Superluminal Spacetime Slab

    CERN Document Server

    Deck-Léger, Zoé-Lise

    2016-01-01

    Spacetime media offers new opportunities for wave manipulation. Here we study superluminal slabs, and show that the amplitudes of the reflected waves are controlled by the velocity of the medium. In addition, the backward wave continuously scans from the specular to the collinear angle. A diagrammatic method is provided for insight into the deflection angles. A fundamental symmetry between sub- and superluminal scattering is derived from this diagrammatic description.

  5. Disk-Wind Connection During the Heartbeats of GRS 1915+105

    DEFF Research Database (Denmark)

    Zoghbi, Abderahmen; Miller, M. C.; King, A. L.

    2016-01-01

    Disk and wind signatures are seen in the soft state of Galactic black holes, while the jet is seen in the hard state. Here we study the disk–wind connection in the ρ class of variability in GRS 1915+105 using a joint NuSTAR–Chandra observation. The source shows 50 s limit cycle oscillations. By i...

  6. Is OPERA Neutrino Superluminal Propagation similar to Gain-Assisted Superluminal Light Propagation

    CERN Document Server

    Pankovic, Vladan

    2011-01-01

    In this work we consider a possible conceptual similarity between recent, amazing OPERA experiment of the superluminal propagation of neutrino and experiment of the gain-assisted superluminal light propagation realized about ten years ago. Last experiment refers on the propagation of the light, precisely laser pulse through a medium, precisely caesium atomic gas, with characteristic anomalous dispersion and corresponding negative group-velocity index that implies superluminal propagation of the light through this medium. Nevertheless all this, at it has been pointed out by authors, "is not at odds with causality or special relativity", since it simply represents "a direct consequence of the classical interference between ... different frequency components". We observe that OPERA experiment is in many aspects conceptually very similar to the gain-assisted superluminal light propagation, including superposition of the neutrinos component and superluminality magnitudes. For this reason we suppose that OPERA expe...

  7. RXTE Observations of the Microquasar GRS 1915+105

    CERN Document Server

    Rodríguez, J; Tagger, M

    2001-01-01

    We analyse a set of three RXTE Target of Opportunity observations of the Galactic microquasar GRS 1915+105, observed in April 2000. We concentrate on the timing properties of the source, and examine the properties of a low frequency QPO, with its harmonic, in several energy ranges. The source was found in two different states of the spectro/temporal classification of Belloni et al. (2000), and exhibited in the three observations a strong, low frequency QPO together with a strong harmonic. We discuss the properties of the QPO, of its harmonic and of their spectral behaviour in the framework of the Accretion Ejection Instability (AEI) (Tagger & Pellat, 1999; Varni\\`ere, Rodriguez & Tagger, 2001; Rodriguez et al., 2001).

  8. INTEGRAL observation of GRS 1739-278 in outburst

    DEFF Research Database (Denmark)

    Filippova, E.; Kuulkers, E.; Alfonso-Garzon, J.

    2014-01-01

    During the Galactic bulge monitoring observation (Atel #438) performed on 2014 March 19 from 11.00 to 14:42 (UTC), the black-hole candidate GRS 1739-278 (ATel #5986) was also seen by INTEGRAL. The source is detected by IBIS/ISGRI up to an energy of about 200 keV. The estimated ISGRI flux is 143......). The 3-200 keV X-ray flux derived from the spectral fit is 5E-9 ergs/cm^2/s (not corrected for absorption). This spectral shape is reminiscent of that displayed by black-hole candidates in the canonical hard state. Further observations of the source with INTEGRAL are planned for March 28....

  9. Nuclear knowledge management: The GRS realisation

    Energy Technology Data Exchange (ETDEWEB)

    Beraha, D. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Wissensmanagement in der Anlagen- und Reaktorsicherheit, Forschungsgelaende, 85748 Garching (Germany)]. E-mail: David.Beraha@grs.de; Heigl, T.; Puhr-Westerheide, P. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Wissensmanagement in der Anlagen- und Reaktorsicherheit, Forschungsgelaende, 85748 Garching (Germany)

    2005-07-01

    The paper describes the set-up of a knowledge management system at GRS. A knowledge model has been used as a guideline through the stages of knowledge-related activities, including specification of the knowledge goals, knowledge identification, acquisition, development, use, dissemination, preservation and assessment of the knowledge management system. The activities related to these stages are described. In addition, process-oriented knowledge management as a means to integrate knowledge-related activities into everyday work, and semantic technologies for modelling knowledge domains and for improving search for relevant documents are presented. (author)

  10. Tachyons, Lamb shifts and superluminal chaos

    Science.gov (United States)

    Tomaschitz, R.

    2000-10-01

    An elementary account on the origins of cosmic chaos in an open and multiply connected universe is given; there is a finite region in the open 3-space in which the world-lines of galaxies are chaotic, and the mixing taking place in this chaotic nucleus of the universe provides a mechanism to create equidistribution. The galaxy background defines a distinguished frame of reference and a unique cosmic time order; in this context superluminal signal transfer is studied. Tachyons are described by a real Proca field with negative mass square, coupled to a current of subluminal matter. Estimates on tachyon mixing in the geometric optics limit are derived. The potential of a static point source in this field theory is a damped periodic function. We treat this tachyon potential as a perturbation of the Coulomb potential, and study its effects on energy levels in hydrogenic systems. By comparing the induced level shifts to high-precision Lamb shift measurements and QED calculations, we suggest a tachyon mass of 2.1 keV/c2 and estimate the tachyonic coupling strength to subluminal matter. The impact of the tachyon field on ground state hyperfine transitions in hydrogen and muonium is investigated. Bounds on atomic transition rates effected by tachyon radiation as well as estimates on the spectral energy density of a possible cosmic tachyon background radiation are derived.

  11. The asymmetric compact jet of GRS 1915+105

    CERN Document Server

    Ribó, M; Mirabel, I F

    2004-01-01

    We present multiepoch VLBA observations of the compact jet of GRS 1915+105 conducted at 15.0 and 8.4 GHz during a {\\it plateau} state of the source in 2003 March-April. These observations show that the compact jet is clearly asymmetric. Assuming an intrinsically symmetric continuous jet flow, using Doppler boosting arguments and an angle to the line of sight of $\\theta=70\\degr$, we obtain values for the velocity of the flow in the range 0.3--0.5$c$. These values are much higher than in previous observations of such compact jet, although much lower than the highly relativistic values found during individual ejection events. These preliminary results are compatible with current ideas on the jet flow velocity for black holes in the low/hard state.

  12. NEW SUPERLUMINAL QUASAR-1633+382 AND THE BLAZAR-GAMMA-RAY CONNECTION

    NARCIS (Netherlands)

    BARTHEL, PD; CONWAY, JE; MYERS, ST; PEARSON, TJ; READHEAD, ACS

    1995-01-01

    We report detection of superluminal motion in the core of 4C 38.41, associated with the z = 1.814 quasar 1633+382. The dominant nucleus in the similar to 30 kpc triple morphology of the radio source displays a core-jet structure on the milliarcsecond scale, and a jet component is found moving

  13. The Phantom of the OPERA: Superluminal Neutrinos

    CERN Document Server

    Ma, Bo-Qiang

    2011-01-01

    This report presents a brief review on the experimental measurements of the muon neutrino velocities from the OPERA, Fermilab and MINOS experiments and that of the (anti)-electron neutrino velocities from the supernova SN1987a, and consequently on the theoretical aspects to attribute the data as signals for superluminality of neutrinos. Different scenarios on how to understand and treat the background fields in the standard model extension frameworks are pointed out. Challenges on interpreting the OPERA result as a signal of neutrino superluminality are briefly reviewed and discussed. It is also pointed out that a covariant scenario of Lorentz violation can avoid the refutation on the OPERA experiment.

  14. Spectroscopy of superluminous supernova host galaxies

    DEFF Research Database (Denmark)

    Leloudas, G.; Kruehler, T.; Schulze, S

    2015-01-01

    Superluminous supernovae (SLSNe) are very bright explosions that were only discovered recently and that show a preference for occurring in faint dwarf galaxies. Understanding why stellar evolution yields different types of stellar explosions in these environments is fundamental in order to both...... uncover the elusive progenitors of SLSNe and to study star formation in dwarf galaxies. In this paper, we present the first results of our project to study SUperluminous Supernova Host galaxIES, focusing on the sample for which we have obtained spectroscopy. We show that SLSNe-I and SLSNe-R (hydrogen...

  15. The Relationship Between X-ray Luminosity and Major Flare Launching in GRS 1915+105

    CERN Document Server

    Punsly, Brian

    2012-01-01

    We perform the most detailed analysis to date of the X-ray state of the Galactic black hole candidate GRS 1915+105 just prior to (0 to 4 hours) and during the brief (1 to 7 hour) ejection of major (superluminal) radio flares. A very strong model independent correlation is found between the 1.2 keV - 12 keV X-ray flux 0 to 4 hours before flare ejections with the peak optically thin 2.3 GHz emission of the flares. This suggests a direct physical connection between the energy in the ejection and the luminosity of the accretion flow preceding the ejection. In order to quantify this concept, we develop techniques to estimate the intrinsic (unabsorbed) X-ray luminosity, $L_{\\mathrm{intrinsic}}$, from RXTE ASM data and to implement known methods to estimate the time averaged power required to launch the radio emitting plasmoids, $Q$ (sometimes called jet power). We find that the distribution of intrinsic luminosity from 1.2 keV - 50 keV, $L_{\\mathrm{intrinsic}}(1.2 - 50)$, is systematically elevated just before ejec...

  16. Pair Production Constraints on Superluminal Neutrinos Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.

    2012-02-16

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  17. Superluminality, Black Holes and Effective Field Theory

    CERN Document Server

    Goon, Garrett

    2016-01-01

    Under the assumption that a UV theory does not display superluminal behavior, we ask what constraints on superluminality are satisfied in the effective field theory (EFT). We study two examples of effective theories: quantum electrodynamics (QED) coupled to gravity after the electron is integrated out, and the flat-space galileon. The first is realized in nature, the second is more speculative, but they both exhibit apparent superluminality around non-trivial backgrounds. In the QED case, we attempt, and fail, to find backgrounds for which the superluminal signal advance can be made larger than the putative resolving power of the EFT. In contrast, in the galileon case it is easy to find such backgrounds, indicating that if the UV completion of the galileon is (sub)luminal, quantum corrections must become important at distance scales of order the Vainshtein radius of the background configuration, much larger than the naive EFT strong coupling distance scale. Such corrections would be reminiscent of the non-per...

  18. Revealing the binary origin of Type Ic superluminous supernovae through nebular hydrogen emission

    Science.gov (United States)

    Moriya, Takashi J.; Liu, Zheng-Wei; Mackey, Jonathan; Chen, Ting-Wan; Langer, Norbert

    2015-12-01

    We propose that nebular Hα emission, as detected in the Type Ic superluminous supernova iPTF13ehe, stems from matter that is stripped from a companion star when the supernova ejecta collide with it. The temporal evolution, the line broadening, and the overall blueshift of the emission are consistent with this interpretation. We scale the nebular Hα luminosity predicted for Type Ia supernovae in single-degenerate systems to derive the stripped mass required to explain the Hα luminosity of iPTF13ehe. We find a stripped mass of 0.1-0.9 solar masses, assuming that the supernova luminosity is powered by radioactivity or magnetar spin down. Because a central heating source is required to excite the Hα emission, an interaction-powered model is not favored for iPTF13ehe if the Hα emission is from stripped matter. We derive a companion mass of more than 20 solar masses and a binary separation of less than about 20 companion radii based on the stripping efficiency during the collision, indicating that the supernova progenitor and the companion formed a massive close binary system. If Type Ic superluminous supernovae generally occur in massive close binary systems, the early brightening observed previously in several Type Ic superluminous supernovae may also be due to the collision with a close companion. Observations of nebular hydrogen emission in future Type Ic superluminous supernovae will enable us to test this interpretation.

  19. OPERA superluminal neutrinos and Kinematics in Finsler spacetime

    CERN Document Server

    Chang, Zhe; Wang, Sai

    2011-01-01

    The OPERA collaboration recently reported that muon neutrinos could be superluminal. More recently, Cohen and Glashow pointed that such superluminal neutrinos would be suppressed since they lose their energies rapidly via bremsstrahlung. In this Letter, we propose that Finslerian nature of spacetime could account for the superluminal phenomena of particles. The Finsler spacetime permits the existence of superluminal behavior of particles while the casuality still holds. A new dispersion relation is obtained in a class of Finsler spacetime. It is shown that the superluminal speed is linearly dependent on the energy per unit mass of the particle. We find that such a superluminal speed formula is consistent with data of OPERA, MINOS and Fermilab-1979 neutrino experiments as well as observations on neutrinos from SN1987a.

  20. Symmetry, causal structure and superluminality in Finsler spacetime

    CERN Document Server

    Chang, Zhe; Wang, Sai

    2012-01-01

    The superluminal behaviors of neutrinos were reported by the OPERA collaboration recently. It was also noticed by Cohen and Glashow that, in standard quantum field theory, the superluminal neutrinos would lose their energy via the Cherenkov-like process rapidly. Finslerian special relativity may provide a framework to cooperate with the OPERA neutrino superluminality without Cherenkov-like process. We present clearly the symmetry, causal structure and superluminality in Finsler spacetime. The principle of relativity and the causal law are preserved. The energy and momentum are well defined and conserved in Finslerian special relativity. The Cherenkov-like process is proved to be forbidden kinematically and the superluminal neutrinos would not lose energy in their distant propagations from CERN to the Gran Sasso Laboratory. The energy dependence of neutrino superluminality is studied based on the reported data of the OPERA collaboration as well as other groups.

  1. GRS 1758–258: RXTE Monitoring of a Rare Persistent Hard State Black Hole

    Directory of Open Access Journals (Sweden)

    M. Obst

    2011-01-01

    Full Text Available GRS 1758–258 is the least studied of the three persistent black hole X-ray binaries in our Galaxy. It is also one of only two known black hole candidates, including all black hole transients, which shows a decrease of its 3-10 keV flux when entering the thermally dominated soft state, rather than an increase.We present the spectral evolution of GRS 1758–258 from RXTE-PCA observations spanning a time of about 11 years from 1996 to 2007. During this time, seven dim soft states are detected. We also consider INTEGRAL monitoring observations of the source and compare the long-term behavior to that of the bright persistent black hole X-ray binary Cygnus X-1. We discuss the observed state transitions in the light of physical scenarios for black hole transitions.

  2. Field signature for apparently superluminal particle motion

    Science.gov (United States)

    Land, Martin

    2015-05-01

    In the context of Stueckelberg's covariant symplectic mechanics, Horwitz and Aharonovich [1] have proposed a simple mechanism by which a particle traveling below light speed almost everywhere may exhibit a transit time that suggests superluminal motion. This mechanism, which requires precise measurement of the particle velocity, involves a subtle perturbation affecting the particle's recorded time coordinate caused by virtual pair processes. The Stueckelberg framework is particularly well suited to such problems, because it permits pair creation/annihilation at the classical level. In this paper, we study a trajectory of the type proposed by Horwitz and Aharonovich, and derive the Maxwell 4-vector potential associated with the motion. We show that the resulting fields carry a signature associated with the apparent superluminal motion, providing an independent test for the mechanism that does not require direct observation of the trajectory, except at the detector.

  3. Field signature for apparently superluminal particle motion

    CERN Document Server

    Land, Martin

    2016-01-01

    In the context of Stueckelberg's covariant symplectic mechanics, Horwitz and Aharonovich have proposed a simple mechanism by which a particle traveling below light speed almost everywhere may exhibit a transit time that suggests superluminal motion. This mechanism, which requires precise measurement of the particle velocity, involves a subtle perturbation affecting the particle's recorded time coordinate caused by virtual pair processes. The Stueckelberg framework is particularly well suited to such problems, because it permits pair creation/annihilation at the classical level. In this paper, we study a trajectory of the type proposed by Horwitz and Aharonovich, and derive the Maxwell 4-vector potential associated with the motion. We show that the resulting fields carry a signature associated with the apparent superluminal motion, providing an independent test for the mechanism that does not require direct observation of the trajectory, except at the detector.

  4. Superluminal propagation: Light cone and Minkowski spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Mugnai, D. [' Nello Carrara' Institute of Applied Physics, CNR Florence Research Area, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)]. E-mail: d.mugnai@ifac.cnr.it

    2007-05-14

    Superluminal behavior has been extensively studied in recent years, especially with regard to the topic of superluminality in the propagation of a signal. Particular interest has been devoted to Bessel-X waves propagation, since some experimental results showed that these waves have both phase and group velocities greater that light velocity c. However, because of the lack of an exact definition of signal velocity, no definite answer about the signal propagation (or velocity of information) has been found. The present Letter is a short note that deals in a general way with this vexed question. By analyzing the field of existence of the Bessel X-pulse in pseudo-Euclidean spacetime, it is possible to give a general description of the propagation, and to overcome the specific question related to a definition of signal velocity.

  5. Superluminal radiation by uniformly moving charges

    Science.gov (United States)

    Tomaschitz, Roman

    2003-03-01

    The emission of superluminal quanta (tachyons) by freely propagating particles is scrutinized. Estimates are derived for spontaneous superluminal radiation from electrons moving close to the speed of the Galaxy in the microwave background. This is the threshold velocity for tachyon radiation to occur, a lower bound. Quantitative estimates are also given for the opposite limit, tachyon radiation emitted by ultra-relativistic electrons in linear colliders and supernova shock waves. The superluminal energy flux is studied and the spectral energy density of the radiation is derived, classically as well as in second quantization. There is a transversal bosonic and a longitudinal fermionic component of the radiation. We calculate the power radiated, its angular dependence, the mean energy of the radiated quanta, absorption and emission rates, as well as tachyonic number counts. We explain how the symmetry of the Einstein /A-coefficients connects to time-symmetric wave propagation and to the Wheeler-Feynman absorber theory. A relation between the tachyon mass and the velocity of the Local Group of galaxies is suggested.

  6. Silicon distribution on the lunar surface obtained by Kaguya GRS

    Science.gov (United States)

    Kim, Kyeong Ja; Kobayashi, Masanori; Elphic, Richard; Karouji, Yuzuru; Hamara, Dave; Kobayashi, Shingo; Nagaoka, Hiroshi; Rodriguez, Alexis; Yamashita, Naoyuki; Reedy, Robert; Hasebe, Nobuyuki

    Gamma ray spectrometry (GRS) provides a powerful tool to map and characterize the elemental composition of the upper tens centimeters of solid planetary surfaces. Elemental maps generated by the Kaguya GRS (KGRS) include natural radioactive as well as major elements maps (e.g., Fe, Ca, and Ti). Analysis of the Si gamma ray has been investigated using the 4934 keV Si peak produced by the thermal neutron interaction (28) Si(n,gammag) (29) Si, generated during the interaction of galactic cosmic rays and surface material containing Si. The emission rate of gamma rays is directly proportional to the abundance of Si from the lunar surface; however, it is also affected by the thermal neutron density in the lunar surface. Thus, we corrected the Si GRS data by a low energy neutron data (appear to consist of primarily of mafic rocks. Our elemental map of Si using Kaguya GRS data shows that the highland areas of both near side and far side of the Moon have higher abundance of Si, and the mare regions of the near side of the Moon have the lowest Si abundance on the Moon. Our study clearly shows that there are a number of Si enriched areas compared to that of Apollo 16 site. This result is similar to the mineralogical data obtained by Diviner. The feldspathic highland areas are confirmed through the elemental map of Si by the Kaguya GRS data. When the Si map of Kaguya GRS data is compared with the LRO’s mineralogical map, a reasonable agreement in understanding of the dichotomy between lunar mafic and feldspathic regions of the moon is confirmed. On the other hand, compositional matches between the surface rocks and GRS data may represent the dominant rock composition for a given region.

  7. Constraints and tests of the OPERA superluminal neutrinos.

    Science.gov (United States)

    Bi, Xiao-Jun; Yin, Peng-Fei; Yu, Zhao-Huan; Yuan, Qiang

    2011-12-09

    The superluminal neutrinos detected by OPERA indicate Lorentz invariance violation (LIV) of the neutrino sector at the order of 10(-5). We study the implications of the result in this work. We find that such a large LIV implied by OPERA data will make the neutrino production process π → μ + ν(μ) kinematically forbidden for a neutrino energy greater than about 5 GeV. The OPERA detection of neutrinos at 40 GeV can constrain the LIV parameter to be smaller than 3×10(-7). Furthermore, the neutrino decay in the LIV framework will modify the neutrino spectrum greatly. The atmospheric neutrino spectrum measured by the IceCube Collaboration can constrain the LIV parameter to the level of 10(-12). The future detection of astrophysical neutrinos of galactic sources is expected to be able to give an even stronger constraint on the LIV parameter of neutrinos.

  8. Resolving 7 problems with OPERA's superluminal neutrino experiment

    CERN Document Server

    Ehrlich, Robert

    2011-01-01

    Physicists have raised many troubling inconsistencies with the OPERA claim of superluminal neutrinos that cast doubt on its validity. This paper examines ways that 7 of these inconsistencies can be resolved. It also discusses evidence that the electron neutrino is superluminal, based on previously published cosmic ray observations, and secondarily a re-examination of tritium beta decay data.

  9. On the Superluminal Motion of Radio-Loud AGNs

    Indian Academy of Sciences (India)

    Zhi-Bin Zhang; Yi-Zhen Zhang

    2011-03-01

    Apparent superluminal motion of different radio-loud AGNs are similarly related with beaming effect. The cosmological expanding effect would play no part in the superluminal motion of radio galaxies, BL Lacertae objects as well as quasars.Meanwhile, we confirm that estimates for apparent velocity app and Doppler boosting factor based on multi-wavelength combination and variability are comparable.

  10. GRS - Guarantee of results for grid-connected solar photovoltaic systems; GRS - Garantierte Resultate von Solarstromanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Ch.; Frei, R.

    2001-07-01

    This final report for the Swiss Federal Office of Energy describes the development of a performance guarantee for the power delivered by grid-connected photovoltaic (PV) power plant. This is important for investors, who need to be able to calculate the price of the energy produced by the PV plant. The report examines the results of various case studies and experience gained with GRS contracts developed in different countries including Switzerland, the Netherlands, France and Germany. The problems encountered, which provided feedback for the further development of the contract presented in the report, are discussed. The model contract, which proposes a framework which provides many possible variations and adaptations, is presented in detail. Various problem areas such as guaranteed energy yield, meteorological references, correction methods, failure detection, dispute settlement and many other points are covered.

  11. Modelling Oscillations in GRS 1915+105 Jet Emission

    CERN Document Server

    Collins, R S; Cox, S J; Collins, Ross S.; Kaiser, Christian R.; Cox, Simon J.

    2002-01-01

    We have studied time variability in the flux from the flat spectrum synchrotron radiation of the Blandford & Konigl (1979) model for relativistic, conical jets. The resulting model has been applied to the flux variation of the flat spectrum of GRS 1915+105 observed by Fender & Pooley (2000). This comparison has highlighted a fundamental problem of the Blandford & Konigl (1979) model in that it requires unphysically large electron densities to explain the flux levels observed from the flat spectrum of GRS 1915+105.

  12. Has superluminal light propagation been observed?

    OpenAIRE

    Zhang, Yuan-Zhong

    2000-01-01

    It says in the report$^1$ by Wang et al. that a negative group velocity $u=-c/310$ is obtained and that a pulse advancement shift 62-ns is measured. The authors claim that the negative group velocity is associated with superluminal light propagation and that the pulse advancement is not at odds with causality or special relativity. However, it is shown here that their conclusions above are not true. Furthermore, I give some suggestion concerning a re-definition of group-velocity and a new exp...

  13. Simultaneous integral/rxte observations of grs 1915+105

    Directory of Open Access Journals (Sweden)

    j. Rodriguez

    2004-01-01

    Full Text Available Presentamos los primeros resultados de observaciones INTEGRAL y RXTE simult aneas del microcuasar GRS 1915+105. Nos enfocamos en el an alisis de la unica observaci on altamente variable, mostrando que pudimos haber observado una nueva clase de variabilidad. Luego estudiamos la dependencia energ etica de una QPO con base en nuestras observaciones regulares.

  14. Identification of the donor in GRS 1915+105

    CERN Document Server

    Greiner, J; Cuby, J G; Castro-Tirado, A J; Mennickent, R E

    2000-01-01

    We report on the results of medium-resolution spectroscopy of GRS 1915+105 in the H and K band using the 8m VLT at ESO. We clearly identify absorption bandheads from CO12 and CO13. Together with other features this results in a classification of the donor as a K-M III star.

  15. Accretion-Ejection Instability and a "Magnetic Flood" scenario for GRS 1915+105

    CERN Document Server

    Tagger, M

    1999-01-01

    We present an instability, occurring in the inner region of magnetized accretion disks, which seems to be a good candidate to explain the low-frequency QPO observed in many X-ray binaries. We then briefly show how, in the remarkable case of the microquasar GRS 1915+105, identifying this QPO with our instability leads to a scenario for the $\\sim$ 30 mn cycles of this source. In this scenario the cycles are controlled by the build-up of magnetic flux in the disk.

  16. The Accretion-Ejection Instability and a "Magnetic Flood" scenario for GRS 1915+105

    CERN Document Server

    Tagger, M

    2000-01-01

    I present a global view of recent results on the Accretion-Ejection Instability (AEI), described in more details in other contributions to this workshop. These results address essentially the characteristics of the AEI as a good candidate to explain the low-frequency QPO of X-ray binaries, in particular (at $\\sim 1-10$ Hz) of micro-quasars. I then discuss how, if the AEI is considered as the source of the QPO, a possible scenario can be considered where the $\\sim 30$ mn. cycles of GRS 1915+105 are controlled by the evolution of magnetic flux in the disk.

  17. Properties of Magnetars Mimicking 56Ni-powered Light Curves in Type IC Superluminous Supernovae

    Science.gov (United States)

    Moriya, Takashi J.; Chen, Ting-Wan; Langer, Norbert

    2017-02-01

    Many Type Ic superluminous supernovae have light-curve decline rates after their luminosity peak, which are close to the nuclear decay rate of {}56{Co}, consistent with the interpretation that they are powered by {}56{Ni} and possibly pair-instability supernovae. However, their rise times are typically shorter than those expected from pair-instability supernovae, and Type Ic superluminous supernovae are often suggested to be powered by magnetar spin-down. If magnetar spin-down is actually a major mechanism to power Type Ic superluminous supernovae, it should be able to produce decline rates similar to the {}56{Co} decay rate rather easily. In this study, we investigate the conditions for magnetars under which their spin-down energy input can behave like the {}56{Ni} nuclear decay energy input. We find that an initial magnetic field strength within a certain range is sufficient to keep the magnetar energy deposition within a factor of a few of the {}56{Co} decay energy for several hundreds of days. Magnetar spin-down needs to be by almost pure dipole radiation with the braking index close to three to mimic {}56{Ni} in a wide parameter range. Not only late-phase {}56{Co}-decay-like light curves, but also rise time and peak luminosity of most {}56{Ni}-powered light curves can be reproduced by magnetars. Bolometric light curves for more than 700 days are required to distinguish the two energy sources solely by them. We expect that more slowly declining superluminous supernovae with short rise times should be found if they are mainly powered by magnetar spin-down.

  18. Superluminal Radio Features in the M87 Jet and the Site of Flaring TeV Gamma-ray Emission

    CERN Document Server

    Cheung, C C; Stawarz, L

    2007-01-01

    Superluminal motion is a common feature of radio jets in powerful gamma-ray emitting active galactic nuclei. Conventionally, the variable emission is assumed to originate near the central supermassive black-hole where the jet is launched on parsec scales or smaller. Here, we report the discovery of superluminal radio features within a distinct flaring X-ray emitting region in the jet of the nearby radio galaxy M87 with the Very Long Baseline Array. This shows that these two phenomenological hallmarks -- superluminal motion and high-energy variability -- are associated, and we place this activity much further (>=120 pc) from the ``central engine'' in M87 than previously thought in relativistic jet sources. We argue that the recent excess very high-energy TeV emission from M87 reported by the H.E.S.S. experiment originates from this variable superluminal structure, thus providing crucial insight into the production region of gamma-ray emission in more distant blazars.

  19. On Superluminal Particles and the Extended Relativity Theories

    Science.gov (United States)

    Castro, Carlos

    2012-09-01

    Superluminal particles are studied within the framework of the Extended Relativity theory in Clifford spaces ( C-spaces). In the simplest scenario, it is found that it is the contribution of the Clifford scalar component π of the poly-vector-valued momentum which is responsible for the superluminal behavior in ordinary spacetime due to the fact that the effective mass {M} = sqrt{ M2 - π2 } is imaginary (tachyonic). However, from the point of view of C-space, there is no superluminal (tachyonic) behavior because the true physical mass still obeys M 2>0. Therefore, there are no violations of the Clifford-extended Lorentz invariance and the extended Relativity principle in C-spaces. It is also explained why the charged muons (leptons) are subluminal while its chargeless neutrinos may admit superluminal propagation. A Born's Reciprocal Relativity theory in Phase Spaces leads to modified dispersion relations involving both coordinates and momenta, and whose truncations furnish Lorentz-violating dispersion relations which appear in Finsler Geometry, rainbow-metrics models and Double (deformed) Special Relativity. These models also admit superluminal particles. A numerical analysis based on the recent OPERA experimental findings on alleged superluminal muon neutrinos is made. For the average muon neutrino energy of 17 GeV, we find a value for the magnitude |{M } | = 119.7 MeV that, coincidentally, is close to the mass of the muon m μ =105.7 MeV.

  20. Renewable Energy: Solar Fuels GRC and GRS

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Nathan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Gray, Nancy Ryan [Gordon Research Conferences, West Kingston, RI (United States)

    2010-02-26

    This Gordon Research Conference seeks to bring together chemists, physicists, materials scientists and biologists to address perhaps the outstanding technical problem of the 21st Century - the efficient, and ultimately economical, storage of energy from carbon-neutral sources. Such an advance would deliver a renewable, environmentally benign energy source for the future. A great technological challenge facing our global future is energy. The generation of energy, the security of its supply, and the environmental consequences of its use are among the world's foremost geopolitical concerns. Fossil fuels - coal, natural gas, and petroleum - supply approximately 90% of the energy consumed today by industrialized nations. An increase in energy supply is vitally needed to bring electric power to the 25% of the world's population that lacks it, to support the industrialization of developing nations, and to sustain economic growth in developed countries. On the geopolitical front, insuring an adequate energy supply is a major security issue for the world, and its importance will grow in proportion to the singular dependence on oil as a primary energy source. Yet, the current approach to energy supply, that of increased fossil fuel exploration coupled with energy conservation, is not scaleable to meet future demands. Rising living standards of a growing world population will cause global energy consumption to increase significantly. Estimates indicate that energy consumption will increase at least two-fold, from our current burn rate of 12.8 TW to 28 - 35 TW by 2050. - U.N. projections indicate that meeting global energy demand in a sustainable fashion by the year 2050 will require a significant fraction of the energy supply to come carbon free sources to stabilize atmospheric carbon dioxide levels at twice the pre-anthropogenic levels. External factors of economy, environment, and security dictate that this global energy need be met by renewable and sustainable

  1. The X-ray nova GRS 1739-278 near the Galactic center

    Science.gov (United States)

    Borozdin, K. N.; Revnivtsev, M. G.; Trudolyubov, S. P.; Aleksandrovich, N. L.; Sunyaev, R. A.; Skinner, G. K.

    1998-07-01

    The soft X-ray nova GRS 1739-278 flared up in 1996 near the Galactic center. We present the observations of this interesting source, a black-hole candidate, with the instruments on board the Mir-Kvant module and the RXTE satellite. The TTM data allow the spectrum of the X-ray nova to be studied during the rise in its brightness. The source's spectrum in this period is satisfactorily described by a power law with a gradually increasing index. The RXTE spectra after the source passed its maximum brightness have the appearance that is typical of the high and very high states of black-hole candidates; they are described by a two-component model. The broad-band spectra of the source are discussed in terms of the processes that proceed near an accreting black hole in a binary system.

  2. The X-ray Nova GRS 1739-278 near the Galactic Center

    CERN Document Server

    Borozdin, K N; Trudolyubov, S P; Aleksandrovich, N L; Sunyaev, R A; Skinner, G K

    1999-01-01

    The soft X-ray nova GRS 1739-278 flared up in 1996 near the Galactic center. We present the observations of this interesting source, a black-hole candidate, with the instruments on board the Mir-Kvant module and the RXTE satellite. The TTM data allow the spectrum of the X-ray nova to be studied during the rise in its brightness. The source's spectrum in this period is satisfactorily described by a power law with a gradually increasing index. The RXTE spectra after the source passed its maximum brightness have the appearance that is typical of the high and ultrahigh states of black-hole candidates; they are described by a two-component model. The broad-band spectra of the source are discussed in terms of the processes that proceed near an accreting black hole in a binary system.

  3. Hard X-ray observations of GRS/KS 1730-312 with GRANAT/SIGMA.

    Science.gov (United States)

    Trudolyubov, S.; Gilfanov, M.; Churazov, E.; Sunyaev, R.; Borozdin, K.; Alexandrovich, N.; Khavenson, N.; Novikov, B.; Vargas, M.; Goldwurm, A.; Paul, J.; Denis, M.; Mandrou, P.; Roques, J.-P.; Jourdain, E.; Borrel, V.

    1996-02-01

    The results of transient X-ray source KS/GRS 1730-312 observations with GRANAT/SIGMA are reported. The source was discovered on September 23, 1994 and at the maximum of the light curve was the brightest one in the Galactic Center region in the 35-200 keV energy domain. Within ≡5 d the hard X-ray flux from GRS/KS 1730-312 declined below the SIGMA sensitivity limit. The average 35-200 keV spectrum can be approximated by the power law spectrum with photon index ≡2.5 or by bremsstrahlung model with temperature ≡70 keV. Some steepening of the 35-200 keV spectrum with time was marginally detected. According to the TTM (Mir-KVANT) data the decline of hard X-ray flux was accompanied by notable increase of the flux in the standard X-ray band (2-10 keV). During 5 d the 2-10 keV band contribution to the 2-300 keV luminosity increased from ≡20-25% to ≡80-90%. Combined TTM and SIGMA data indicate that the broad band (2-300 keV) spectrum evolution may be described in terms of appearance and fast increase of the soft spectral component accompanied with decrease and possible steepening of the hard component.

  4. Simultaneous multi-wavelength observations of GRS 1915+105

    DEFF Research Database (Denmark)

    Fuchs, Y.; Rodriguez, Cayo Juan Ramos; Mirabel, I.F.;

    2003-01-01

    We present the result of multi-wavelength observations of the microquasar GRS 1915 + 105 in a plateau state with a luminosity of similar to7.5 x 10(38) erg s(-1) (similar to40% L-Edd), conducted simultaneously with the INTEGRAL and RXTE satellites, the ESOstarstar/NTT, the Ryle Telescope, the NRAO......(starstarstar) VLA and VLBA, in 2003 April 2-3. For the first time were observed concurrently in GRS 1915 + 105 all of the following properties: a strong steady optically thick radio emission corresponding to a powerful compact jet resolved with the VLBA, bright near-IR emission, a strong QPO at 2.5 Hz in the X...

  5. Scientific codes developed and used at GRS. Nuclear simulation chain

    Energy Technology Data Exchange (ETDEWEB)

    Schaffrath, Andreas; Sonnenkalb, Martin; Sievers, Juergen; Luther, Wolfgang; Velkov, Kiril [Gesellschaft fuer Anlagen und Reaktorsicherheit (GRS) gGmbH, Garching/Muenchen (Germany). Forschungszentrum

    2016-05-15

    Over 60 technical experts of the reactor safety research division of the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH are developing and validating reliable methods and computer codes - summarized under the term nuclear simulation chain - for the safety-related assessment for all types of nuclear power plants (NPP) and other nuclear facilities considering the current state of science and technology. This nuclear simulation chain has to be able to simulate and assess all relevant physical processes and phenomena for all operating states and (severe) accidents. In the present contribution, the nuclear simulation chain developed and applied by GRS as well as selected examples of its application are presented. The latter demonstrate impressively the width of its scope and its performance. The GRS codes can be passed on request to other (national as well as international) organizations. This contributes to a worldwide increase of the nuclear safety standards. The code transfer is especially important for developing and emerging countries lacking the financial means and/or the necessary know-how for this purpose. At the end of this contribution, the respective course of action is described.

  6. The 2:3:6 QPO structure in GRS 1915+105 and cubic subharmonics in the context of relativistic diskoseismology

    CERN Document Server

    Ortega-Rodr\\'\\iguez, Manuel; López-Barquero, Vanessa; Matamoros-Alvarado, Bryan; Venegas-Li, Ariadna

    2013-01-01

    We propose a simple toy model to explain the 2:3:6 QPO structure in GRS 1915+105 and, more generally, the 2:3 QPO structure in XTE J1550-564, GRO J1655-40, and H 1743-322. The model exploits the onset of subharmonics in the context of diskoseismology. The results include the prediction that, as better data become available, a QPO with a frequency of twice the higher twin frequency and a large quality factor will be observed in twin peak sources, as it might already have been observed in the especially active GRS 1915+105.

  7. Nonlocal Quantum Information Transfer Without Superluminal Signalling and Communication

    Science.gov (United States)

    Walleczek, Jan; Grössing, Gerhard

    2016-09-01

    It is a frequent assumption that—via superluminal information transfers—superluminal signals capable of enabling communication are necessarily exchanged in any quantum theory that posits hidden superluminal influences. However, does the presence of hidden superluminal influences automatically imply superluminal signalling and communication? The non-signalling theorem mediates the apparent conflict between quantum mechanics and the theory of special relativity. However, as a `no-go' theorem there exist two opposing interpretations of the non-signalling constraint: foundational and operational. Concerning Bell's theorem, we argue that Bell employed both interpretations, and that he finally adopted the operational position which is associated often with ontological quantum theory, e.g., de Broglie-Bohm theory. This position we refer to as "effective non-signalling". By contrast, associated with orthodox quantum mechanics is the foundational position referred to here as "axiomatic non-signalling". In search of a decisive communication-theoretic criterion for differentiating between "axiomatic" and "effective" non-signalling, we employ the operational framework offered by Shannon's mathematical theory of communication, whereby we distinguish between Shannon signals and non-Shannon signals. We find that an effective non-signalling theorem represents two sub-theorems: (1) Non-transfer-control (NTC) theorem, and (2) Non-signification-control (NSC) theorem. Employing NTC and NSC theorems, we report that effective, instead of axiomatic, non-signalling is entirely sufficient for prohibiting nonlocal communication. Effective non-signalling prevents the instantaneous, i.e., superluminal, transfer of message-encoded information through the controlled use—by a sender-receiver pair —of informationally-correlated detection events, e.g., in EPR-type experiments. An effective non-signalling theorem allows for nonlocal quantum information transfer yet—at the same time

  8. Astronomy. ASASSN-15lh: A highly super-luminous supernova.

    Science.gov (United States)

    Dong, Subo; Shappee, B J; Prieto, J L; Jha, S W; Stanek, K Z; Holoien, T W-S; Kochanek, C S; Thompson, T A; Morrell, N; Thompson, I B; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Brown, J S; Bufano, F; Chen, Ping; Conseil, E; Danilet, A B; Falco, E; Grupe, D; Kiyota, S; Masi, G; Nicholls, B; Olivares E, F; Pignata, G; Pojmanski, G; Simonian, G V; Szczygiel, D M; Woźniak, P R

    2016-01-15

    We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu ,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10(45) ergs s(-1), which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10(52) ergs, challenging the magnetar model for its engine. Copyright © 2016, American Association for the Advancement of Science.

  9. The Volumetric Rate of Superluminous Supernovae at z~1

    CERN Document Server

    Prajs, S; Smith, M; Levan, A; Karpenka, N V; Edwards, T D P; Walker, C R; Wolf, W M; Balland, C; Carlberg, R; Howell, A; Lidman, C; Pain, R; Pritchet, C; Ruhlmann-Kleider, V

    2016-01-01

    We present a measurement of the volumetric rate of superluminous supernovae (SLSNe) at z~1, measured using archival data from the first four years of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We develop a method for the photometric classification of SLSNe to construct our sample. Our sample includes two previously spectroscopically-identified objects, and a further new candidate selected using our classification technique. We use the point-source recovery efficiencies from Perrett et.al. (2010) and a Monte Carlo approach to calculate the rate based on our SLSN sample. We find that the three identified SLSNe from SNLS give a rate of 91 (+76/-36) SNe/Yr/Gpc^3 at a volume-weighted redshift of z=1.13. This is equivalent to 2.2 (+1.8/-0.9) x10^-4 of the volumetric core collapse supernova rate at the same redshift. When combined with other rate measurements from the literature, we show that the rate of SLSNe increases with redshift in a manner consistent with that of the cosmic star formati...

  10. GRS defective axonal distribution as a potential contributor to distal spinal muscular atrophy type V pathogenesis in a new model of GRS-associated neuropathy.

    Science.gov (United States)

    Seo, Ah Jung; Park, Byung Sun; Jung, Junyang

    2014-11-01

    Distal spinal muscular atrophy type V (dSMA-V), a hereditary axonal neuropathy, is a glycyl-tRNA synthetase (GRS)-associated neuropathy caused by a mutation in GRS. In this study, using an adenovirus vector system equipped with a neuron-specific promoter, we constructed a new GRS-associated neuropathy mouse model. We found that wild-type GRS (WT) is distributed in peripheral axons, dorsal root ganglion (DRG) cell bodies, central axon terminals and motor neuron cell bodies in the mouse model. In contrast, the L129P mutant GRS was localized in DRG and motor neuron cell bodies. Thus, we propose that the disease-causing L129P mutant is linked to a distribution defect in peripheral nerves in vivo.

  11. Superluminal Motion and Polarization in Blazars

    Institute of Scientific and Technical Information of China (English)

    Jun-Hui Fan; Yong-Jiu Wang; Jiang-He Yang; Cheng-Yue Su

    2004-01-01

    A relativistic beaming model has been successfully used to explain the observed properties of active galactic nuclei (AGNs). In this model there are two emission components, a boosted one and an unbeamed one, shown up in the radio band as the core and lobe components. The luminosity ratio of the core to the lobe is defined as the core-dominance parameter (R = LCore/LLobe) The de-beamed radio luminosity (Ldbjet) in the jet is assumed to be proportional to the unbeamed luminosity (Lub) in the co-moving frame, i.e., f = Ldbjet/Lub and f is determined in our previous paper. We further discuss the relationship between BL Lacertae objects(BLs) and flat spectrum radio quasars (FSRQs), which are subclasses of blazars with different degrees of polarization, using the calculated values of the ratio f for a sample of superluminal blazars. We found 1) that the BLs show smaller averaged Doppler factors and Lorentz factors, larger viewing angles and higher coredominance parameters than do the FSRQs, and 2) that in the polarization-core dominance parameter plot (P - log R) the BLs and FSRQs occupy a scattered region, but in a revised plot (logP/c(m) - logR), they gather around two different lines, suggesting that they have some different intrinsic properties.

  12. Spectrum formation in Superluminous Supernovae (Type I)

    CERN Document Server

    Mazzali, P A; Pian, E; Greiner, J; Kann, D A; ARI-LJMU,; UK,; Garching, MPA; Germany,; Southampton, Univ; INAF-IASFBO,; Italy,; Pisa, SNS; Garching, MPE; Tautenburg,; Germany),

    2016-01-01

    The near-maximum spectra of most superluminous supernovae that are not dominated by interaction with a H-rich CSM (SLSN-I) are characterised by a blue spectral peak and a series of absorption lines which have been identified as OII. SN2011kl, associated with the ultra-long gamma-ray burst GRB111209A, also had a blue peak but a featureless optical/UV spectrum. Radiation transport methods are used to show that the spectra (not including SN2007bi, which has a redder spectrum at peak, like ordinary SNe Ic) can be explained by a rather steep density distribution of the ejecta, whose composition appears to be typical of carbon-oxygen cores of massive stars which can have low metal content. If the photospheric velocity is ~10000-15000 km/s, several lines form in the UV. OII lines, however, arise from very highly excited lower levels, which require significant departures from Local Thermodynamic Equilibrium to be populated. These SLSNe are not thought to be powered primarily by 56Ni decay. An appealing scenario is th...

  13. Super-luminous supernovae from PESSTO

    CERN Document Server

    Nicholl, M; Jerkstrand, A; Inserra, C; Chen, T -W; Kotak, R; Valenti, S; Howell, D A; McCrum, M; Margheim, S; Rest, A; Benetti, S; Fraser, M; Gal-Yam, A; Smith, K W; Sullivan, M; Young, D R; Baltay, C; Hadjiyska, E; McKinnon, R; Rabinowitz, D; Walker, E S; Feindt, U; Nugent, P; Lawrence, A; Mead, A; Anderson, J P; Sollerman, J; Taddia, F; Leloudas, G; Mattila, S; Elias-Rosa, N

    2014-01-01

    We present optical spectra and light curves for three hydrogen-poor super-luminous supernovae followed by the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). Time series spectroscopy from a few days after maximum light to 100 days later shows them to be fairly typical of this class, with spectra dominated by Ca II, Mg II, Fe II and Si II, which evolve slowly over most of the post-peak photospheric phase. We determine bolometric light curves and apply simple fitting tools, based on the diffusion of energy input by magnetar spin-down, \\Ni decay, and collision of the ejecta with an opaque circumstellar shell. We investigate how the heterogeneous light curves of our sample (combined with others from the literature) can help to constrain the possible mechanisms behind these events. We have followed these events to beyond 100-200 days after peak, to disentangle host galaxy light from fading supernova flux and to differentiate between the models, which predict diverse behaviour at this phase. Models p...

  14. Superluminous Supernovae: No Threat from Eta Carinae

    Science.gov (United States)

    Thomas, Brian; Melott, A. L.; Fields, B. D.; Anthony-Twarog, B. J.

    2008-05-01

    Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of 1044 Joules. It was proposed that the progenitor may have been a massive evolved star similar to η Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. η Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, η Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over 104 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous” for other reasons. However, due to reddening and extinction by the interstellar medium, η Carinae is unlikely to trigger such effects to any significant degree.

  15. Superluminous supernovae: No threat from Eta Carinae

    CERN Document Server

    Thomas, Brian C; Fields, Brian D; Anthony-Twarog, Barbara J

    2007-01-01

    Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of ~10^44 Joules. It was proposed that the progenitor may have been a massive evolved star similar to Eta Carinae, which resides in our own galaxy at a (poorly determined) distance of ~2.5 kpc. Eta Carinae appears ready to detonate, and in fact had an outburst in 1843. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma Ray Burst oriented toward the Earth, Eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over ~10^4 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possib...

  16. First stars, hypernovae, and superluminous supernovae

    Science.gov (United States)

    Nomoto, Ken'Ichi

    2016-07-01

    After the big bang, production of heavy elements in the early universe takes place starting from the formation of the first (Pop III) stars, their evolution, and explosion. The Pop III supernova (SN) explosions have strong dynamical, thermal, and chemical feedback on the formation of subsequent stars and evolution of galaxies. However, the nature of Pop III stars/supernovae (SNe) have not been well-understood. The signature of nucleosynthesis yields of the first SN can be seen in the elemental abundance patterns observed in extremely metal-poor (EMP) stars. We show that the abundance patterns of EMP stars, e.g. the excess of C, Co, Zn relative to Fe, are in better agreement with the yields of hyper-energetic explosions (Hypernovae, (HNe)) rather than normal supernovae. We note the large variation of the abundance patterns of EMP stars propose that such a variation is related to the diversity of the GRB-SNe and posssibly superluminous supernovae (SLSNe). For example, the carbon-enhanced metal-poor (CEMP) stars may be related to the faint SNe (or dark HNe), which could be the explosions induced by relativistic jets. Finally, we examine the various mechanisms of SLSNe.

  17. Extended Lorentz code of a superluminal particle

    CERN Document Server

    Ter-Kazarian, G

    2012-01-01

    While the OPERA experimental scrutiny is ongoing in the community, in the present article we construct a toy model of {\\it extended Lorentz code} (ELC) of the uniform motion, which will be a well established consistent and unique theoretical framework to explain the apparent violations of the standard Lorentz code (SLC), the possible manifestations of which arise in a similar way in all particle sectors. We argue that in the ELC-framework the propagation of the superluminal particle, which implies the modified dispersion relation, could be consistent with causality. Furthermore, in this framework, we give a justification of forbiddance of Vavilov-Cherenkov (VC)-radiation/or analog processes in vacuum. To be consistent with the SN1987A and OPERA data, we identify the neutrinos from SN1987A and the light as so-called {\\it 1-th type} particles carrying the {\\it individual Lorentz motion code} with the velocity of light $c_{1}\\equiv c$ in vacuum as maximum attainable velocity for all the 1-th type particles. Ther...

  18. Simultaneous Observations of GRS 1758-258 in 1997 by VLA, IRAM, SEST, RXTE and OSSE Spectroscopy and Timing

    CERN Document Server

    Lin, D; Liang, E P; Bridgman, T; Smith, D M; Martí, J; Durouchoux, P; Mirabel, I F; Rodríguez, L F; Durouchoux, Ph.

    1999-01-01

    We report the results of our multi-wavelength observations of GRS 1758-258 made in August 1997. The energy bands include radio, millimeter, X-ray, and gamma-ray. The observations enable us to obtain a complete spectrum of the source over an energy range of 2 - 500 keV. The spectrum shows that GRS 1758-258 was in its hard state. It is well fitted by the Sunyaev-Titarchuk (ST) Compton scattering model. The spectrum is also fit by a power law with an exponential cutoff (PLE) plus a soft black-body component. The temperature of the soft component is about 1.2 keV, and the energy flux is less than 1.5% of the total X- and gamma-ray flux. The deduced hydrogen column density is in the range of (0.93 - 2.0) 10^{22} cm^{-2}. No significant iron lines are detected. The radio emission has a flat energy spectrum. The daily radio, X-ray and gamma-ray light curves show that GRS 1758-258 was stable during the observation period, but was highly variable on smaller time scales in X- and gamma-rays. The power density spectra a...

  19. How superluminal motion can lead to backward time travel

    CERN Document Server

    Nemiroff, Robert J

    2015-01-01

    It is commonly asserted that superluminal particle motion can enable backward time travel, but little has been written providing details. It is shown here that the simplest example of a "closed loop" event -- a twin paradox scenario where a single spaceship both traveling out and returning back superluminally -- does {\\it not} result in that ship straightforwardly returning to its starting point before it left. However, a more complicated scenario -- one where the superluminal ship first arrives at an intermediate destination moving subluminally -- can result in backwards time travel. This intermediate step might seem physically inconsequential but is shown to break Lorentz-invariance and be oddly tied to the sudden creation of a pair of spacecraft, one of which remains and one of which annihilates with the original spacecraft.

  20. The GRS/GRC from the perspective of a graduate student and first time attendee.

    Science.gov (United States)

    Russo, Corey D

    2013-05-01

    The networking and collaborative opportunities afforded to the attendees of the Ocean and Human Health Gordon Research Seminar (GRS) and the Gordon Research Conference (GRC) are vast and great. The GRS/GRC, in particular, has the capability of facilitating interlaboratory and interdisciplinary collaborations. The following article highlights the benefits associated with attending the GRS/GRC as a graduate student and first time attendee.

  1. HESS upper limits on very high energy gamma-ray emission from the microquasar GRS 1915+105

    Science.gov (United States)

    H.E.S.S. Collaboration; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Boutelier, T.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Conrad, J.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'c.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fiasson, A.; Förster, A.; Fontaine, G.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jung, I.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Keogh, D.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J.-P.; Lohse, T.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Orford, K. J.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schönwald, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sushch, I.; Sikora, M.; Skilton, J. L.; Sol, H.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Superina, G.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Venter, L.; Vialle, J. P.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.

    2009-12-01

    Context: High energy particles reside in the relativistic jets of microquasars, making them possible sources of very high energy radiation (VHE, >100 GeV). Detecting this emission would provide a new handle on jet physics. Aims: Observations of the microquasar GRS 1915+105 with the HESS telescope array were undertaken in 2004-2008 to search for VHE emission. Methods: Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and direction of the incident gamma rays. Results: There is no evidence for a VHE gamma-ray signal either from the direction of the microquasar or its vicinity. An upper limit of 6.1× 10-13 ph cm-2 s-1 (99.9% confidence level) is set on the photon flux above 410 GeV, equivalent to a VHE luminosity of ˜ 1034 erg s-1 at 11 kpc. Conclusions: The VHE to X-ray luminosity ratio in GRS 1915+105 is at least four orders of magnitude lower than the ratio observed in gamma-ray binaries. The VHE radiative efficiency of the compact jet is less than 0.01% based on its estimated total power of 1038 erg s-1. Particle acceleration in GRS 1915+105 is not efficient at high energies and/or the magnetic field is too strong. It is also possible that VHE gamma-rays are produced by GRS 1915+105, but the emission is highly time-dependent. Supported by CAPES Foundation, Ministry of Education of Brazil.

  2. Jet Stability and the Generation of Superluminal and Stationary Components

    Science.gov (United States)

    Agudo, Ivan; Gomez, Jose-Luis; Marti, Jose-Maria; Ibanez, Jose-Maria; Marscher, Alan P.; Alberdi, Antonio; Aloy, Miguel-Angel; Hardee, Philip E.

    2001-01-01

    We present a numerical simulation of the response of an expanding relativistic jet to the ejection of a superluminal component. The simulation has been performed with a relativistic time-dependent hydrodynamical code from which simulated radio maps are computed by integrating the transfer equations for synchrotron radiation. The interaction of the superluminal component with the underlying jet results in the formation of multiple conical shocks behind the main perturbation. These trailing components can be easily distinguished because they appear to be released from the primary superluminal component instead of being ejected from the core. Their oblique nature should also result in distinct polarization properties. Those appearing closer to the core show small apparent motions and a very slow secular decrease in brightness and could be identified as stationary components. Those appearing farther downstream are weaker and can reach superluminal apparent motions. The existence of these trailing components indicates that not all observed components necessarily represent major perturbations at the jet inlet; rather, multiple emission components can be generated by a single disturbance in the jet. While the superluminal component associated with the primary perturbation exhibits a rather stable pattern speed, trailing components have velocities that increase with distance from the core but move at less than the jet speed. The trailing components exhibit motion and structure consistent with the triggering of pinch modes by the superluminal component. The increase in velocity of the trailing components is an indirect consequence of the acceleration of the expanding fluid, which is assumed to be relativistically hot; if observed, such accelerations would therefore favor an electron-positron (as opposed to proton rest mass) dominated jet.

  3. Propagation of Superluminous L-O Mode Waves During Geomagnetic Activities

    Institute of Scientific and Technical Information of China (English)

    XIAO Fuliang; CHEN Lunjin; ZHENG Huinan; ZHOU Qinghua; WANG Shui

    2008-01-01

    The effect of the azimuthal angle ψ of the wave vector k on the propagation characteristics of the superluminous L-O mode waves (together with a case of the R-X mode) during different geomagnetic activities using a three-dimensional (3D) ray-tracing method is investigated.This work is primarily an extension of our previous two-dimensional study in which the wave azimuthal angle was not considered.We present numerical simulations for this mode which is generated in the source cavity along a 70° night geomagnetic field line at the specific altitude of 1.5RE (where RE is the Earth's radius).It is found that,as in the two-dimensional case,the trajectory of L-O mode starting in the source meridian plane (or the wave azimuthal angle ψ=180°) can reach the lowest latitude;whereas it basically stays at relatively higher latitudes starting off the source meridian plane (or ψ≠180°).The results reveal that under appropriate conditions,the superluminous L-O mode waves may exist in the radiation belts of the Earth,but this remains to be supplemented by observational data.

  4. A Blind Pilot: Who is a Super-Luminal Observer?

    Directory of Open Access Journals (Sweden)

    Rabounski D.

    2008-04-01

    Full Text Available This paper discusses the nature of a hypothetical super-luminal observer who, as well as a real (sub-light speed observer, perceives the world by light waves. This consideration is due to that fact that the theory of relativity permits different frames of reference, including light-like and super-luminal reference frames. In analogy with a blind pilot on board a supersonic jet aeroplane (or missile, perceived by blind people, it is concluded that the light barrier is observed in the framework of only the light signal exchange experiment.

  5. Control of superluminal transit through a heterogeneous medium

    CERN Document Server

    Kulkarni, M; Rao, V S C Manga; Gupta, S Dutta

    2004-01-01

    We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneous medium is shown to lead to subluminal-to-superluminal transmission depending on the volume fraction of the metal inclusions. The predictions of phase time calculations are verified by explicit calculations of the transmitted pulse shapes. We also demonstrate the independence of the phase time on system width and the volume fraction under specific conditions.

  6. The EOS module SALTREP for the code TOUGH2-GRS; Das EOS-Modul SALTREP fuer den Code TOUGH2-GRS

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Martin

    2014-02-15

    TOUGH2 is a code for the simulation of multi-phase flow processes in porous media which was developed by the Lawrence Berkeley National Laboratory, California, USA. TOUGH2 uses EOS modules to introduce phases and phase components and to cal-culate their thermodynamic state. For the simulation of NaCl dissolution and precipita-tion as well as transport of multiple volatile components, GRS has developed the EOS module SALTREP. The module belongs to the code TOUGH2-GRS.00a, which is an extended version of the TOUGH2 code developed by GRS. The manual describes the module SALTREP in its current state of development.

  7. There is Neither Classical Bug with a Superluminal Shadow Nor Quantum Absolute Collapse Nor (Subquantum) Superluminal Hidden Variable

    CERN Document Server

    Pankovic, V; Krmar, M; Radovanovic, M; Pankovic, Vladan; Predojevic, Milan; Krmar, Miodrag; Radovanovic, Milan

    2005-01-01

    In this work we analyse critically Griffiths's example of the classical superluminal motion of a bug shadow. Griffiths considers that this example is conceptually very close to quantum nonlocality or superluminality,i.e. quantum breaking of the famous Bell inequality. Or, generally, he suggests implicitly an absolute asymmetric duality (subluminality vs. superluminality) principle in any fundamental physical theory.It, he hopes, can be used for a natural interpretation of the quantum mechanics too. But we explain that such Griffiths's interpretation retires implicitly but significantly from usual, Copenhagen interpretation of the standard quantum mechanical formalism. Within Copenhagen interpretation basic complementarity principle represents, in fact, a dynamical symmetry principle (including its spontaneous breaking, i.e. effective hiding by measurement). Similarly, in other fundamental physical theories instead of Griffiths's absolute asymmetric duality principle there is a dynamical symmetry (including it...

  8. Spectrum formation in superluminous supernovae (Type I)

    Science.gov (United States)

    Mazzali, P. A.; Sullivan, M.; Pian, E.; Greiner, J.; Kann, D. A.

    2016-06-01

    The near-maximum spectra of most superluminous supernovae (SLSNe) that are not dominated by interaction with a H-rich circum-stellar medium (SLSN-I) are characterized by a blue spectral peak and a series of absorption lines which have been identified as O II. SN 2011kl, associated with the ultra-long gamma-ray burst GRB111209A, also had a blue peak but a featureless optical/ultraviolet (UV) spectrum. Radiation transport methods are used to show that the spectra (not including SN 2007bi, which has a redder spectrum at peak, like ordinary SNe Ic) can be explained by a rather steep density distribution of the ejecta, whose composition appears to be typical of carbon-oxygen cores of massive stars which can have low metal content. If the photospheric velocity is ˜10 000-15 000 km s-1, several lines form in the UV. O II lines, however, arise from very highly excited lower levels, which require significant departures from local thermodynamic equilibrium to be populated. These SLSNe are not thought to be powered primarily by 56Ni decay. An appealing scenario is that they are energized by X-rays from the shock driven by a magnetar wind into the SN ejecta. The apparent lack of evolution of line velocity with time that characterizes SLSNe up to about maximum is another argument in favour of the magnetar scenario. The smooth UV continuum of SN 2011kl requires higher ejecta velocities (˜20 000 km s-1): line blanketing leads to an almost featureless spectrum. Helium is observed in some SLSNe after maximum. The high-ionization near-maximum implies that both He and H may be present but not observed at early times. The spectroscopic classification of SLSNe should probably reflect that of SNe Ib/c. Extensive time coverage is required for an accurate classification.

  9. Searching for X-ray luminous 'normal' galaxies in 2dfGRS

    CERN Document Server

    Tzanavaris, P; Georgakakis, A

    2006-01-01

    We cross-correlated the Chandra XASSIST and XMM-Newton Serendipitous Source Catalogues with the 2 degree Field Galaxy Redshift Survey (2dfGRS) database. Our aim was to identify the most X-ray luminous (L_X > 10^42 erg s^-1) examples of galaxies in the local Universe whose X-ray emission is dominated by stellar processes rather than AGN activity ('normal' galaxies) as well as to test the empirical criterion log(f_X/f_O) -2. We performed a similar search in two nearby-galaxy samples from the literature. All 44 galaxies in the Zezas (2001) sample have log(f_X/f_O) -2, the majority of which are massive ellipticals. Three of these have L_X > 10^42 erg s^-1 .

  10. The evolution of superluminous supernova LSQ14mo and its interacting host galaxy system

    CERN Document Server

    Chen, T -W; Smartt, S J; Mazzali, P A; Yates, R M; Moriya, T J; Inserra, C; Langer, N; Kruehler, T; Pan, Y -C; Kotak, R; Galbany, L; Schady, P; Wiseman, P; Greiner, J; Schulze, S; Man, A W S; Jerkstrand, A; Smith, K W; Dennefeld, M; Baltay, C; Bolmer, J; Kankare, E; Knust, F; Maguire, K; Rabinowitz, D; Rostami, S; Sullivan, M; Young, D R

    2016-01-01

    We present and analyse an extensive dataset of the superluminous supernova LSQ14mo (z = 0.256), consisting of a multi-colour lightcurve from -30 d to +70 d in the rest-frame and a series of 6 spectra from PESSTO covering -7 d to +50 d. This is among the densest spectroscopic coverage, and best-constrained rising lightcurve, for a fast-declining hydrogen-poor superluminous supernova. The bolometric lightcurve can be reproduced with a millisecond magnetar model with ~ 4 M_sol ejecta mass, and the temperature and velocity evolution is also suggestive of a magnetar as the power source. Spectral modelling indicates that the SN ejected ~ 6 M_sol of CO-rich material with a kinetic energy of ~ 7 x 10^51 erg, and suggests a partially thermalised additional source of luminosity between -2 d and +22 d. This may be due to interaction with a shell of material originating from pre-explosion mass loss. We further present a detailed analysis of the host galaxy system of LSQ14mo. PESSTO and GROND imaging show three spatially ...

  11. Accretion States of the Galactic Micro Quasar GRS 1758-258

    Science.gov (United States)

    Soria, Roberto; Mehdipour, Missagh; Broderick, Jess W.; Hao, JingFang; Hannikainen, Diana C.; Pottschmidt, Katja; Zhang, Shuang-Nan

    2011-01-01

    We present the results of a radio and X-ray study of the Galactic micro quasar GRS 1758-258, using unpublished archival data and new observations. We focus in particular on the 2000-2002 state transitions, and on its more quiet behaviour in 2008-2009. Our spectral and timing analysis of the XMM-Newton data shows that the source was in the canonical intermediate, soft and hard states in 2000 September 19,2001 March 22 and 2002 September 28, respectively. We estimate the disk size, luminosity and temperature, which are consistent with a black hole mass approx.10 Solar Mass, There is much overlap between the range of total X-ray luminosities (on average approx. 0.02L(sub Edd)) in the hard and soft states, and probably between the corresponding mass accretion rates; in fact, the hard state is often more luminous. The extended radio lobes seen in 1992 and 1997 are still present in 2008-2009. The 5-GHz radio core flux density has shown variability between approx. 0.1-0.5 mJy over the last two decades. This firmly places GRS 1758-258 in the radio-quiet sequence of Galactic black holes, in the radio/X-ray plane. We note that this dichotomy is similar to the dichotomy between the radio/X-ray sequences of Seyfert and radio galaxies. We propose that the different radio efficiency of the two sequences is due to relativistic electron/positron jets in radio-loud black holes, and sub-relativistic, thermally dominated outflows in radio-quiet sources.

  12. The volumetric rate of superluminous supernovae at z ˜ 1

    Science.gov (United States)

    Prajs, S.; Sullivan, M.; Smith, M.; Levan, A.; Karpenka, N. V.; Edwards, T. D. P.; Walker, C. R.; Wolf, W. M.; Balland, C.; Carlberg, R.; Howell, D. A.; Lidman, C.; Pain, R.; Pritchet, C.; Ruhlmann-Kleider, V.

    2017-01-01

    We present a measurement of the volumetric rate of superluminous supernovae (SLSNe) at z ˜ 1.0, measured using archival data from the first four years of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We develop a method for the photometric classification of SLSNe to construct our sample. Our sample includes two previously spectroscopically identified objects, and a further new candidate selected using our classification technique. We use the point-source recovery efficiencies from Perrett et al. and a Monte Carlo approach to calculate the rate based on our SLSN sample. We find that the three identified SLSNe from SNLS give a rate of 91^{+76}_{-36} SNe yr-1 Gpc-3 at a volume-weighted redshift of z = 1.13. This is equivalent to 2.2^{+1.8}_{-0.9}× 10^{-4} of the volumetric core-collapse supernova rate at the same redshift. When combined with other rate measurements from the literature, we show that the rate of SLSNe increases with redshift in a manner consistent with that of the cosmic star formation history. We also estimate the rate of ultra-long gamma-ray bursts based on the events discovered by the Swift satellite, and show that it is comparable to the rate of SLSNe, providing further evidence of a possible connection between these two classes of events. We also examine the host galaxies of the SLSNe discovered in SNLS, and find them to be consistent with the stellar-mass distribution of other published samples of SLSNe.

  13. Superluminal Physics and Instantaneous Physics as New Trends in Research

    Directory of Open Access Journals (Sweden)

    Smarandache F.

    2012-01-01

    Full Text Available In a similar way as passing from Euclidean Geometry to Non-Euclidean Geometry, we can pass from Subluminal Physics to Superluminal Physics, and further to Instantaneous Physics. In the lights of two consecutive successful CERN experiments with superlumi- nal particles in the Fall of 2011, we believe that these two new fields of research should begin developing.

  14. X-Ray Transient in Musca (GRS 1121-68 = GS 1124-683)

    DEFF Research Database (Denmark)

    Lund, Niels; Brandt, Søren; Makino, F.

    1991-01-01

    Research Institute, Lyngby; and Space Research Institute, Moscow), report: "A new x-ray source in Musca, GRS 1121-68, has been discovered in data obtained by the WATCH detectors on Jan. 9. The spectrum of the source was harder than that of the Crab nebula, and the flux was about twice that from...... the Crab and increasing slowly during the observation. The source remained at a constant intensity level on Jan. 10. On Jan. 5 this source was not bright enough to be detectable by WATCH. The preliminary position is R.A. = 11h21m, Decl. = -68.1 deg (equinox 1950.0; uncertainty about 1 deg). We have...... not found any catalogued hard x-ray sources within our error circle; however, close to the given position, we have noted the existence of a radio pulsar (at R.A. = 11h10m, Decl. = -69 deg) with a period of 0.8 s, and a gamma-ray burst source, GRB 820829B, detected by Venera 13/14 in 1982. We have...

  15. Multifrequency observations of the superluminal quasar 3C 345

    Science.gov (United States)

    Bregman, J. N.; Glassgold, A. E.; Huggins, P. J.; Neugebauer, G.; Soifer, B. T.; Matthews, K.; Roellig, T. P. L.; Bregman, J. D.; Witteborn, F. C.; Lester, D. F.

    1986-01-01

    Attention is given to the continuum properties of the superluminal quasar 3C 345, on the basis of radio, optical, IR, and X-ray frequency monitorings, as well as by means of simultaneous multifrequency spectra extending from the radio through the X-ray bands. Radio outbursts, which appear to follow IR-optical outbursts by about one year, first occur at the highest frequencies, as expected from optical depth effects; the peak flux is nevertheless often reached at several frequencies at once. The beginning of outbursts, as defined by mm-measurements, corresponds to the appearance of the three known 'superluminal' components. An increase in the X-ray flux during 1979-1980 corresponds to increased radio flux, while the IR flux changes in the opposite sense.

  16. The hypothesis of superluminal neutrinos: Comparing OPERA with other data

    DEFF Research Database (Denmark)

    Drago, A.; Masina, I.; Pagliara, G.

    2012-01-01

    The OPERA Collaboration reported evidence for muonic neutrinos traveling slightly faster than light in vacuum. While waiting further checks from the experimental community, here we aim at exploring some theoretical consequences of the hypothesis that muonic neutrinos are superluminal, considering...... in particular the tachyonic and the Coleman-Glashow cases. We show that a tachyonic interpretation is not only hardly reconciled with OPERA data on energy dependence, but that it clashes with neutrino production from pion and with neutrino oscillations. A Coleman-Glashow superluminal neutrino beam would also...... have problems with pion decay kinematics for the OPERA setup; it could be easily reconciled with SN1987a data, but then it would be very problematic to account for neutrino oscillations. Copyright (C) EPLA, 2012...

  17. Superluminal Spot Pair Events in Astronomical Settings: Sweeping Beams

    CERN Document Server

    Nemiroff, Robert J

    2014-01-01

    Sweeping beams of light can cast spots moving with superluminal speeds across scattering surfaces. Such faster-than-light speeds are well-known phenomena that do not violate special relativity. It is shown here that under certain circumstances, superluminal spot pair creation and annihilation events can occur that provide unique information to observers. These spot pair events are {\\it not} particle pair events -- they are the sudden creation or annihilation of a pair of relatively illuminated spots on a scattering surface. Real spot pair illumination events occur unambiguously on the scattering surface when spot speeds diverge, while virtual spot pair events are observer dependent and perceived only when real spot radial speeds cross the speed of light. Specifically, a virtual spot pair creation event will be observed when a real spot's speed toward the observer drops below $c$, while a virtual spot pair annihilation event will be observed when a real spot's radial speed away from the observer rises above $c...

  18. The hypothesis of superluminal neutrinos: Comparing OPERA with other data

    DEFF Research Database (Denmark)

    Drago, A.; Masina, I.; Pagliara, G.

    2012-01-01

    The OPERA Collaboration reported evidence for muonic neutrinos traveling slightly faster than light in vacuum. While waiting further checks from the experimental community, here we aim at exploring some theoretical consequences of the hypothesis that muonic neutrinos are superluminal, considering...... in particular the tachyonic and the Coleman-Glashow cases. We show that a tachyonic interpretation is not only hardly reconciled with OPERA data on energy dependence, but that it clashes with neutrino production from pion and with neutrino oscillations. A Coleman-Glashow superluminal neutrino beam would also...... have problems with pion decay kinematics for the OPERA setup; it could be easily reconciled with SN1987a data, but then it would be very problematic to account for neutrino oscillations. Copyright (C) EPLA, 2012...

  19. Limiting Superluminal Electron and Neutrino Velocities Using the 2010 Crab Nebula Flare and the IceCube PeV Neutrino Events

    Science.gov (United States)

    Stecker, Floyd W.

    2014-01-01

    The observation of two PetaelectronVolt (PeV)-scale neutrino events reported by Ice Cube allows one to place constraints on Lorentz invariance violation (LIV) in the neutrino sector. After first arguing that at least one of the PetaelectronVolt IceCube events was of extragalactic origin, I derive an upper limit for the difference between putative superluminal neutrino and electron velocities of less than or equal to approximately 5.6 x 10(exp -19) in units where c = 1, confirming that the observed PetaelectronVolt neutrinos could have reached Earth from extragalactic sources. I further derive a new constraint on the superluminal electron velocity, obtained from the observation of synchrotron radiation from the Crab Nebula flare of September, 2010. The inference that the greater than 1 GigaelectronVolt gamma-rays from synchrotron emission in the flare were produced by electrons of energy up to approx. 5.1 PetaelectronVolt indicates the nonoccurrence of vacuum Cerenkov radiation by these electrons. This implies a new, strong constraint on superluminal electron velocities delta(sub e) less than or equal to approximately 5 x 10(exp -21). It immediately follows that one then obtains an upper limit on the superluminal neutrino velocity alone of delta(sub v) less than or equal to approximately 5.6 x 10(exp -19), many orders of magnitude better than the time-of-flight constraint from the SN1987A neutrino burst. However, if the electrons are subluminal the constraint on the absolute value of delta(sub e) less than or equal to approximately 8 x 10(exp -17), obtained from the Crab Nebula gamma-ray spectrum, places a weaker constraint on superluminal neutrino velocity of delta(sub v) less than or equal to approximately 8 x 10(exp -17).

  20. Subluminal and Superluminal Phenomena in a Four-Level Atom

    Institute of Scientific and Technical Information of China (English)

    HAN Ding-An; ZENG Ya-Guang; CAO Hui

    2008-01-01

    In a four-level atomic system,we investigate the light pulse propagation properties interacting with only one laser field.It is shown that in the steady state,the group velocity of the light pulse can be changed from subluminal to superluminal by varying the field detuning.Meanwhile,the effects of the field intensity on the group velocity are also shown.At last,with special parameters,the analytical solution for the group index is also obtained.

  1. Superluminal light propagation via quantum interference in decay channels

    OpenAIRE

    Arun, R.

    2016-01-01

    We examine the propagation of a weak probe light through a coherently driven $Y$-type system. Under the condition that the excited atomic levels decay via same vacuum modes, the effects of quantum interference in decay channels are considered. It is found that the interference in decay channels results in a lossless anomalous dispersion between two gain peaks. We demonstrate that the probe pulse propagation can in principle be switched from subluminal to superluminal due to the decay-induced ...

  2. Unified interpretation of superluminal behaviors in wave propagation

    Energy Technology Data Exchange (ETDEWEB)

    Ranfagni, A. [Istituto di Fisica Applicata ' Nello Carrara' , Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze (Italy); Viliani, G. [Dipartimento di Fisica, Universita di Trento, 38050 Povo, Trento (Italy); Ranfagni, C. [Facolta di Scienze Matematiche Fisiche e Naturali, Corso di Laurea in Fisica dell' Universita di Firenze, Firenze (Italy); Mignani, R. [Dipartimento di Fisica ' Edoardo Amaldi' , Universita degli Studi di Roma ' Roma Tre' , Via della Vasca Navale 84, 00146 Roma (Italy); Ruggeri, R. [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Sezione di Firenze, Firenze (Italy)], E-mail: rocco.ruggeri@isc.cnr.it; Ricci, A.M. [Istituto per le Telecomunicazioni e l' Elettronica della Marina Militare ' Giancarlo Vallauri' (Mariteleradar), Viale Italia 72, 57100 Livorno (Italy)

    2007-10-29

    By using two approaches, we demonstrate that superluminal behaviors in wave propagation can be attributed to mechanisms acting in the near-field limit. One approach is based on complex waves, while the other relies on a path-integral treatment of stochastic motion. The results of the two approaches are comparable, and suitable for interpreting the data obtained in microwave experiments; these experiments, over a wide range of distances, show a time advance which, in any case, is limited to nanoseconds.

  3. INTEGRAL/JEM-X detection of a possible new outburst from GRS 1747-312

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Bozzo, E.; Bordas, P.

    2013-01-01

    -ray binary GRS 1747-312 is active again (as also reported by the MAXI transient alert on 2013-03-11 12:45:25 UT), although it cannot be fully excluded that another X-ray binary has become active in this cluster. The source is detected in the combined JEM-X mosaic at 25 sigma (effective exposure time 12.......5 ksec) with average fluxes of 41+/-3 mCrab in the 3-10 keV energy band and 23+/-4 mCrab in the 10-25 keV energy band. The JEM-X spectrum is well fit by using a black-body model with a temperature of 1.7+/-0.2 keV and an absorption column density fixed to the Galactic value in the direction...... to the cluster, i.e. 6E21 cm^(-2). This gives a 3-10 keV flux of 6.0x10^(-10) ergs/cm^2/s. No type-I X-ray bursts are visible in the JEM-X light-curve. The source is not detected by IBIS/ISGRI. We estimated an upper limit on the source flux in the 20-40 keV energy band of 8 mCrab at 3 sigma confidence level...

  4. The outburst of the X-ray nova GRS 1739-278 in September, 2016

    CERN Document Server

    Mereminskiy, I A; Krivonos, R A; Grebenev, S A; Burenin, R A; Sunyaev, R A

    2016-01-01

    During the scanning observations of the Galactic Center region in August - September 2016 we detected the new outburst of the historical X-ray nova GRS 1739-278, the black hole candidate LMXB system. In this letter we present results of INTEGRAL and Swift-XRT observations taken during the outburst. In hard X-ray band (20-60 keV) the flux from the source raised from $\\sim$11 to $\\sim$30 mCrab between 3 and 14 of September. For nearly 8 days the source has been observed at this flux level and then faded to $\\sim$15 mCrab. The broadband quasi-simultaneous spectrum obtained during the outburst is well described by the absorbed powerlaw with the photon index $\\Gamma=1.86\\pm0.07$ in broad energy range 0.5-150 keV, with absorption corresponding to ${N_{H}}=2.3\\times10^{22}$ cm$^{-2}$ assuming solar abundance. Based on this we can conclude that the source was in the low/hard state. From the lightcurve and spectra we propose that this outburst was `failed', i.e. amount of accreted matter was not sufficient to achieve ...

  5. Long-Term X-ray Monitoring of 1E 1740.7-2942 and GRS 1758-258

    CERN Document Server

    Main, D S; Heindl, W A; Swank, J H; Leventhal, M; Mirabel, I F; Rodríguez, L F

    1999-01-01

    We report on long-term observations of the Galactic-bulge black hole candidates 1E 1740.7-2942 and GRS 1758-258 with the Rossi X-Ray Timing Explorer. 1E 1740.7-2942 has been observed 77 times and GRS 1758-258 has been observed 82 times over the past 1000 days. The flux of each object has varied by no more than a factor of 2.5 during this period, and the indices of the energy spectra have varied by no more than 0.4. The power spectra are similar to other black-hole candidates: flat-topped noise, breaking to a power law. Each object has exhibited a brightening that lasted for several months, and we have a found a time lag between the photon power-law index and the count rate. In both sources, the spectrum is softest during the decline from the brightening. This behavior can be understood in the context of thin-disk and advection-dominated accretion flows coexisting over a wide range of radii, with the implication that both sources have low-mass companions and accrete via Roche-lobe overflow.

  6. Monitoring the Black Hole Binary GRS 1758-258 with INTEGRAL and RXTE

    Science.gov (United States)

    Pottschmidt, Katja; Chernyakova, Masha; Lubinski, Piotr; Migliari, Simone; Smith, David M.; Zdziarski, Andrzej A.; Tomsick, John A.; Bezayiff, N.; Kreykenbohm, Ingo; Kretschmar, Peter; hide

    2008-01-01

    The microquasar GRS 1758-258 is one of only three persistent black hole binaries that spend most of their time in the hard spectral state, the other two being Cyg X-l and 1E 1741.7-2942. It therefore provides the rare opportunity for an extensive long term study of this important black hole state which is associated with strong variability and radio jet emission. INTEGRAL has been monitoring the source since the first Galactic Center Deep Exposure season in spring 2003 during two 2-3 months long Galactic Center viewing epochs each year, amounting to 11 epochs including spring of 2008. With the exception of the last epoch quasi-simultaneous RXTE monitoring observations are available as well. Here we present an analysis of the epoch averaged broad band spectra which display considerable long term variability, most notably the occurrence of two soft/off states, extreme examples for the hysteretic behavior of black hole binaries. The hard source spectrum and long exposures allow us to extend the analysis for several epochs to approximately 800 keV using PICsIT data and address the question of the presence of a non-thermal Comptonization component.

  7. THE SUPERLUMINAL CHARACTER OF THE COMPACT STEEP SPECTRUM QUASAR 3C-216

    NARCIS (Netherlands)

    VENTURI, T; PEARSON, TJ; BARTHEL, PD; HERBIG, T

    We report the results of fourth epoch VLBI observations at 4990.99 MHz, with a resolution of approximately 1 mas, of the compact steep-spectrum quasar 3C 216. Superluminal motion in this object is confirmed. Although a constant superluminal expansion at upsilon(app) = 3.9c +/- 0.6 is not ruled out,

  8. Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS). Annual report 2013/14; Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS). Jahresbericht 2013/14

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-02-15

    The annual report 2013/14 of the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) includes projects and key activities on the following issues: reactor safety, waste disposal, radiation protection, environmental protection and the support of foreign authorities and TSO. The project executing organizations, the governmental funding, share holding and subsidiaries are summarized.

  9. LWR decay heat calculations using a GRS improved ENDF/B-6 based ORIGEN data library

    Energy Technology Data Exchange (ETDEWEB)

    Hesse, U.; Hummelsheim, K.I.; Kilger, R.; Moser, F.E.; Langenbuch, S. [Gesellschaft fur Anlagen- und Reaktorsicherheit (GRS) mbH, Forschungsinstitute, Garching (Germany)

    2008-07-01

    The known ORNL ORIGEN code is widely spread over the world for inventory, activity and decay heat tasks and is used stand-alone or implemented in activation, shielding or burn-up systems. More than 1000 isotopes with more than six coupled neutron capture and radioactive decay channels are handled simultaneously by the code. The characteristics of the calculated inventories, e.g., masses, activities, neutron and photon source terms or the decay heat during short or long decay time steps are achieved by summing over all isotopes, characterized in the ORIGEN libraries. An extended nuclear GRS-ORIGENX data library is now developed for practical appliance. The library was checked for activation tasks of structure material isotopes and for actinide and fission product burn-up calculations compared with experiments and standard methods. The paper is directed to the LWR decay heat calculation features of the new library and shows the differences of dynamical and time integrated results of Endf/B-6 based and older Endf/B-5 based libraries for decay heat tasks compared to fission burst experiments, ANS curves and some other published data. A multi-group time exponential evaluation is given for the fission burst power of {sup 235}U, {sup 238}U, {sup 239}Pu and {sup 241}Pu, to be used in quick LWR reactor accident decay heat calculation tools. (authors)

  10. A Temporal Analysis Indicates a Mildly Relativistic Compact Jet in GRS~1915+105

    CERN Document Server

    Punsly, Brian

    2016-01-01

    Most of our knowledge of the radio morphology and kinematics of X-ray binary partially synchrotron self-absorbed compact jets (hereafter compact jets) is based on the observations of GRS~1915+105 which has the most prominent compact jet. Yet, the compact jet bulk velocity, $v$, is poorly constrained in the literature, $0.07 10$s) X-ray activity associated with 15 GHz flux density $>70$ mJy for $>7$ consecutive days. The radio emission is associated with compact jet emission. Two HPS were monitored at 15 GHz during their termination with e-folding times of 3.8 hrs and 8.6 hrs. We combine this time scale with the scale of spatial variation of the linear source of a VLBA image preceding the fade of one of these HPS in order to estimate the jet speed. Our assumption that the reduction in radio emissivity propagates as an approximate discontinuity down the HPS jet (leaving a weak jet in its wake) indicates $0.17

  11. Disk-Wind Connection During the Heartbeats of GRS 1915+105

    CERN Document Server

    Zoghbi, Abderahmen; King, A L; Miller, M C; Proga, D; Kallman, T; Fabian, A C; Harrison, F A; Kaastra, J; Raymond, J; Reynolds, C S; Boggs, S E; Christensen, F E; Craig, W; Hailey, C J; Stern, D; Zhang, W W

    2016-01-01

    Disk and wind signatures are seen in the soft state of Galactic black holes, while the jet is seen in the hard state. Here we study the disk-wind connection in the $\\rho$ class of variability in GRS 1915+105 using a joint NuSTAR-Chandra observation. The source shows 50 sec limit cycle oscillations. By including new information provided by the reflection spectrum, and using phase-resolved spectroscopy, we find that the change in the inner disk inferred from the blackbody emission is not matched by reflection measurements. The latter is almost constant, independent of the continuum model. The two radii are comparable only if the disk temperature color correction factor changes, an effect that could be due to the changing opacity of the disk caused by changes in metal abundances. The disk inclination is similar to that inferred from the jet axis, and oscillates by ~10 deg. The simultaneous Chandra data show the presence of two wind components with velocities between 500-5000 km/s, and possibly two more with velo...

  12. A timing view of the heartbeat state of GRS 1915+105

    CERN Document Server

    Yan, Shu-Ping; Méndez, Mariano; Liu, Si-Ming; Wang, Na; Li, Xiang-Dong; Ge, Ming-Yu; Liao, Jin-Yuan; Niu, Shu; Qu, Jin-Lu; Ding, Guo-Qiang; Liu, Qing-Zhong; Sun, Wei

    2016-01-01

    We present a timing analysis of two Rossi X-ray Timing Explorer observations of the microquasar GRS 1915+105 during the heartbeat state. The phase-frequency-power maps show that the intermediate-frequency aperiodic X-ray variability weakens as the source softens in the slow rise phase, and when the quasi-periodic oscillation disappears in the rise phase of the pulse of the double-peaked class its sub-harmonic is still present with a hard phase lag. In the slow rise phase, the energy-frequency-power maps show that most of the aperiodic variability is produced in the corona, and may also induce the aperiodic variability observed at low energies from an accretion disk, which is further supported by the soft phase lag especially in the intermediate-frequency range (with a time delay up to 20 ms). In the rise phase of the pulse, the low-frequency aperiodic variability is enhanced significantly and there is a prominent hard lag (with a time delay up to 50 ms), indicating that the variability is induced by extension...

  13. The outburst of the X-ray nova GRS 1739-278 in September 2016

    Science.gov (United States)

    Mereminskiy, I. A.; Filippova, E. V.; Krivonos, R. A.; Grebenev, S. A.; Burenin, R. A.; Sunyaev, R. A.

    2017-03-01

    During the scanning observations of the Galactic center region in late August-September 2016 we detected a new (third) outburst of the historical X-ray nova GRS 1739-278, a presumed black hole in a low-mass X-ray binary. This was reported in the Astronomer's Telegrams (Mereminskiy et al. 2016). In this paper we present the results of INTEGRAL and Swift observations of the outburst development. According to these observations, the flux from the source in the hard X-ray band (20-60 keV) rose from 11 (September 3) to 30 mCrab (September 14), was at the attained level for 8 days, and then returned to 15 mCrab. The spectrum of the source taken at its peak brightness in the energy range 0.5-150 keV could be fitted by a single power law with a photon index of 1.86 ± 0.07 distorted only by photoabsorption corresponding to the hydrogen column density log10 ( N H) = 22.37 under the assumption of a solar abundance. This means that the source at this time was in the low/hard state. Infrared observations with the RTT-150 telescope near the X-ray brightness peak of the source revealed no emission down to 22_ \\cdot ^m 0 (in the r' band) and 20_ \\cdot ^m 9 (in the i' band). At the time of writing the paper we do not yet know whether this outburst ended or only its initial stage was observed. If it ended, then based on the light curve and spectra, we can state that it was a "failed" outburst, i.e., the amount of accreted matter in this episode was insufficient to reach the high or very high state with a soft blackbody component in the spectrum characteristic of developed outbursts.

  14. Would Superluminal Influences Violate the Principle of Relativity?

    CERN Document Server

    Peacock, Kent A

    2013-01-01

    It continues to be alleged that superluminal influences of any sort would be inconsistent with special relativity for the following three reasons: (i) they would imply the existence of a distinguished' frame; (ii) they would allow the detection of absolute motion; and (iii) they would violate the relativity of simultaneity. This paper shows that the first two objections rest upon very elementary misunderstandings of Minkowski geometry and lingering Newtonian intuitions about instantaneity. The third objection has a basis, but rather than invalidating the notion of faster than light influences it points the way to more general conceptions of simultaneity that could allow for quantum nonlocality in a natural way.

  15. Superluminal neutrinos at OPERA confront pion decay kinematics.

    Science.gov (United States)

    Cowsik, Ramanath; Nussinov, Shmuel; Sarkar, Utpal

    2011-12-16

    Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits α=(ν(ν)-c)/c<4×10(-6). We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (ν-c)/c<10(-12).

  16. Similarilies in accretion dynamics in IGR J17091-3624 and GRS 1915+105 as revealed by the study of Comptonizing Efficiency

    Science.gov (United States)

    Sarathi Pal, Partha; Chakrabarti, Sandip Kumar

    2016-07-01

    Variability classes in the enigmatic black hole candidate GRS 1915+105 are known to be correlated with the variation of the Comptonizing Efficiency (CE) which is defined to be the ratio between the number of power-law (hard) photons and seed (soft) photons injected into the Compton cloud. Similarities of light curves of several variability classes of GRS 1915+105 and IGR J17091-3624, some of which are already reported in the literature, motivated us to compute CE for IGR J17091-3624 as well. We find that they are similar to what were reported earlier for GRS 1915+105, even though masses of these objects could be different. The reason is that the both the sizes of the sources of the seed photons and of the Comptonizing corona scale in the same way as the mass of the black hole. This indicates that characterization of variability classes based on CE is likely to be black hole mass independent, in general.

  17. Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects Connection between Superluminal Ejections and Gamma-Ray Flares in Blazars

    CERN Document Server

    Jorstad, S G; Mattox, J R; Aller, M F; Aller, H D; Wehrle, A E; Bloom, S D; Jorstad, Svetlana G; Marscher, Alan P; Mattox, John R; Aller, Margo F; Aller, Hugh D; Wehrle, Ann E; Bloom, Steven D

    2001-01-01

    We examine the coincidence of times of high $\\gamma$-ray flux and ejections of superluminal components from the core in EGRET blazars based on a VLBA monitoring program at 22 and 43 GHz from November 1993 to July 1997. In 23 cases of $\\gamma$-ray flares for which sufficient VLBA data exist, 16 of the flares (in 14 objects) fall within 3$\\sigma$ and 9 of these within 1$\\sigma$ uncertainties of the extrapolated epoch of zero separation from the core of a superluminal radio component. In each of two sources (0528+134 and 1730-130) two successive $\\gamma$-ray flares were followed by the appearance of new superluminal components. We carried out statistical simulations which show that if the number of coincidences $\\ge$ 7 the radio and $\\gamma$-ray events are associated with each other at >99.999% confidence. Our analysis of the observed behavior, including variability of the polarized radio flux, of the sources before, during, and after the $\\gamma$-ray flares suggests that the $\\gamma$-ray events occur in the sup...

  18. H i Absorption in the Steep-Spectrum Superluminal Quasar 3C 216.

    Science.gov (United States)

    Pihlström; Vermeulen; Taylor; Conway

    1999-11-01

    The search for H i absorption in strong compact steep-spectrum sources is a natural way to probe the neutral gas contents in young radio sources. In turn, this may provide information about the evolution of powerful radio sources. The recently improved capabilities of the Westerbork Synthesis Radio Telescope have made it possible to detect a 0.31% (19 mJy) deep neutral atomic hydrogen absorption line associated with the steep-spectrum superluminal quasar 3C 216. The redshift (z=0.67) of the source shifts the frequency of the 21 cm line down to the ultra-high-frequency (UHF) band (850 MHz). The exact location of the H i-absorbing gas remains to be determined by spectral line VLBI observations at 850 MHz. We cannot exclude that the gas might be extended on galactic scales, but we think it is more likely to be located in the central kiloparsec. Constraints from the lack of X-ray absorption probably rule out obscuration of the core region, and we argue that the most plausible site for the H i absorption is in the jet-cloud interaction observed in this source.

  19. Extreme Supernova Models for the Superluminous Transient ASASSN-15lh

    CERN Document Server

    Chatzopoulos, E; Vinko, J; Nagy, A P; Wiggins, B K; Even, W P

    2016-01-01

    The recent discovery of the unprecedentedly superluminous transient ASASSN-15lh (or SN 2015L) challenges all the power-input models that have been proposed for superluminous supernovae. Here we examine some of the few viable interpretations of ASASSN-15lh in the context of a stellar explosion, involving combinations of one or more power inputs. We model the lightcurve of ASASSN-15lh with a hybrid model that includes contributions from magnetar spin-down energy and hydrogen-poor circumstellar interaction. We also investigate models of pure circumstellar interaction with a massive hydrogen-deficient shell and discuss about the lack of interaction features in the observed spectra. We find that ASASSN-15lh can be best modeled by the energetic core-collapse of a ~40 Msun supernova interacting with a hydrogen-poor shell of ~20 Msun. The circumstellar shell and progenitor mass are consistent with a rapidly rotating pulsational pair-instability supernova progenitor as required for strong interaction following the fin...

  20. Extended Linear and Nonlinear Lorentz Transformations and Superluminality

    Directory of Open Access Journals (Sweden)

    Dara Faroughy

    2013-01-01

    Full Text Available Two broad scenarios for extended linear Lorentz transformations (ELTs are modeled in Section 2 for mixing subluminal and superluminal sectors resulting in standard or deformed energy-momentum dispersions. The first scenario is elucidated in the context of four diverse realizations of a continuous function f ( v , with 0 ≤ f ( v ≤ 1 and f ( 0 = f ( c = 1 , which is fitted in the ELT. What goes in the making of the ELT in this scenario is not the boost speed v , as ascertained by two inertial observers in uniform relative motion (URM, but v × f ( v . The second scenario infers the preexistence of two rest-mass-dependent superluminal speeds whereby the ELTs are finite at the light speed c . Particle energies are evaluated in this scenario at c for several particles, including the neutrinos, and are auspiciously found to be below the GKZ energy cutoff and in compliance with a host of worldwide ultrahigh energy cosmic ray data. Section 3 presents two broad scenarios involving a number of novel nonlinear LTs (NLTs featuring small Lorentz invariance violations (LIVs, as well as resurrecting the notion of simultaneity for limited spacetime events as perceived by two observers in URM. These inquiries corroborate that NLTs could be potent tools for investigating LIVs past the customary LTs.

  1. Space-time measures for subluminal and superluminal motions

    CERN Document Server

    Calvo-Mozo, Benjam\\'\\in

    2014-01-01

    In present work we examine the implications on both, space-time measures and causal structure, of a generalization of the local causality postulate by asserting its validity to all motion regimes, the subluminal and superluminal ones. The new principle implies the existence of a denumerable set of metrical null cone speeds, \\{$c_k\\}$, where $c_1$ is the speed of light in vacuum, and $c_k/c \\simeq \\epsilon^{-k+1}$ for $k\\geq2$, where $\\epsilon^2$ is a tiny dimensionless constant which we introduce to prevent the divergence of the $x, t$ measures in Lorentz transformations, such that their generalization keeps $c_k$ invariant and as the top speed for every regime of motion. The non divergent factor $\\gamma_k$ equals $k\\epsilon^{-1}$ at speed $c_k$. We speak then of $k-$timelike and $k-$null intervals and of k-timelike and k-null paths on space-time, and construct a causal structure for each regime. We discuss also the possible transition of a material particle from the subluminal to the first superluminal regim...

  2. Superluminal two-color light in a multiple Raman gain medium

    KAUST Repository

    Kudriašov, V.

    2014-09-17

    We investigate theoretically the formation of two-component light with superluminal group velocity in a medium controlled by four Raman pump fields. In such an optical scheme only a particular combination of the probe fields is coupled to the matter and exhibits superluminal propagation; the orthogonal combination is uncoupled. The individual probe fields do not have a definite group velocity in the medium. Calculations demonstrate that this superluminal component experiences an envelope advancement in the medium with respect to the propagation in vacuum.

  3. Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay.

    Science.gov (United States)

    Qu, Tianliang; Yang, Kaiyong; Han, Xiang; Wu, Suyong; Huang, Yun; Luo, Hui

    2014-01-01

    We propose and analyze a superluminal ring laser gyroscope (RLG) using multilayer optical coatings with huge group delay (GD). This GD assisted superluminal RLG can measure the absolute rotation with a giant sensitivity-enhancement factor of ~10(3); while, the broadband FWHM of the enhancement factor can reach 20 MHz. This superluminal RLG is based on a traditional RLG with minimal re-engineering, and beneficial for miniaturization according to theoretical calculation. The idea of using GD coatings as a fast-light medium will shed lights on the design and application of fast-light sensors.

  4. XMM-Newton Spectroscopy of the Galactic Microquasar GRS 1758-258 in the Peculiar Off/Soft State

    Science.gov (United States)

    Miller, J. M.; Wunands, R.; Rodriguez-Pascual, P. M.; Ferrando, P.; Gaensler, B. M.; Goldwurm, A.; Lewin, W. H. G.; Pooley, D.

    2002-01-01

    We report on an XMM-Newton Reflection Grating Spectrometer observation of the black hole candidate and Galactic microquasar GRS 1758-258. The source entered a peculiar "off/soft" state in 2001 late February in which the spectrum softened while the X-ray flux-and the inferred mass accretion rate-steadily decreased. We find no clear evidence for emission or absorption lines in the dispersed spectra, indicating that most of the observed soft flux is likely from an accretion disk and not from a cool plasma. The accretion disk strongly dominates the spectrum in this lower luminosity state and is only mildly recessed from the marginally stable orbit. These findings may be di8licult to explain in terms of advection-dominated accretion flow (ADAF) models. We discuss these results within the context of ADAF models, simultaneous two-flow models, and observed correlations between hard X-ray flux and jet production.

  5. Preservation of competence within the framework of knowledge management of GRS; Kompetenzerhalt im Rahmen des Wissensmanagements in der Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH

    Energy Technology Data Exchange (ETDEWEB)

    Beraha, D.; Erven, U.; Puhr-Westerheide, P. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Forschungsinstitute, Garching bei Muenchen (Germany)

    2006-06-15

    As a consequence of the loss of competence threatening to arise from the retirement of many experts, countermeasures in the form of expanded and improved training schemes and the development of knowledge management have been introduced by the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH. The new modules of basic as well as specialized training are described. A brief outline is given of the GRS Intranet portal with its integrated document management. The development of a portal for each project allows all project-related information to be combined. An account is presented of initial experience in using methods of knowledge representation and display, and an outlook is given into expected further developments. (orig.)

  6. Identification of the donor in the X-ray binary GRS 1915+105

    CERN Document Server

    Greiner, J; McCaughrean, M J; Castro-Tirado, A J; Mennickent, R E

    2001-01-01

    We report on the results of medium-resolution spectroscopy of GRS 1915+105 in the near-infrared H and K band using the 8m VLT at ESO. We clearly identify absorption bandheads from 12CO and 13CO. Together with other features this results in a classification of the mass-donating star in this binary as a K-M III star, clearly indicating that GRS 1915+105 belongs to the class of low-mass X-ray binaries (LMXB).

  7. 2 years of integral monitoring of GRS 1915+105. II. X-ray spectro-temporal analysis

    DEFF Research Database (Denmark)

    Rodriguez, J.; Shaw, S.E.; Hannikainen, D.C.;

    2008-01-01

    This is the second paper presenting the results of 2 yr of monitoring of GRS 1915+105 with INTEGRAL, RXTE, and the Ryle Telescope. We present the X-ray spectral and temporal analysis of four observations showing strong radio to X-ray correlations. During one observation GRS 1915+105 was in a steady...

  8. Neutrino superluminality without Cherenkov-like processes in Finslerian special relativity

    CERN Document Server

    Chang, Zhe; Wang, Sai; 10.1016/j.physletb.2012.03.002

    2012-01-01

    Recently, Cohen and Glashow [A.G. Cohen, S.L. Glashow, Phys. Rev. Lett. {\\bf 107}, 181803 (2011)] pointed out that the superluminal neutrinos reported by the OPERA would lose their energy rapidly via the Cherenkov-like process. The Cherenkov-like process for the superluminal particles would be forbidden if the principle of special relativity holds in any frame instead violated with a preferred frame. We have proposed that the Finslerian special relativity could account for the data of the neutrino superluminality (arXiv:1110.6673[hep-ph]). The Finslerian special relativity preserves the principle of special relativity and involves a preferred direction while consists with the causality. In this paper, we prove that the energy-momentum conservation is preserved and the energy-momentum is well defined in Finslerian special relativity. The Cherenkov-like process is forbidden in the Finslerian special relativity. Thus, the superluminal neutrinos would not lose energy in their distant propagation.

  9. Superluminal solutions to the Klein-Gordon equation and a causality problem

    CERN Document Server

    Borghardt, A A; Karpenko, D Y

    2003-01-01

    We present a new axially symmetric monochromatic free-space solution to the Klein-Gordon equation propagating with a superluminal group velocity and show that it gives rise to an imaginary part of the causal propagator outside the light cone. We address the question about causality of the spacelike paths and argue that the signal with a well-defined wavefront formed by the superluminal modes would propagate in vacuum with the light speed.

  10. Bessel-X waves: superluminal propagation and the Minkowski space-time

    OpenAIRE

    Mugnai, D.

    2006-01-01

    Superluminal behavior has been extensively studied in recent years, especially with regard to the topic of superluminality in the propagation of a signal. Particular interest has been devoted to Bessel-X waves propagation, since some experimental results showed that these waves have both phase and group velocities greater that light velocity c. However, because of the lack of an exact definition of signal velocity, no definite answer about the signal propagation (or velocity of information) h...

  11. Superluminal Velocities in the Synchronized Space-Time

    Directory of Open Access Journals (Sweden)

    Medvedev S. Yu.

    2014-07-01

    Full Text Available Within the framework of the non-gravitational generalization of the special relativity, a problem of possible superluminal motion of particles and signals is considered. It has been proven that for the particles with non-zero mass the existence of anisotropic light barrier with the shape dependent on the reference frame velocity results from the Tangherlini transformations. The maximal possible excess of neutrino velocity over the absolute velocity of light related to the Earth (using th e clock with instantaneous synchronization has been estimated. The illusoriness of t he acausality problem has been illustrated and conclusion is made on the lack of the upper limit of velocities of signals of informational nature.

  12. On the impossibility of superluminal travel: the warp drive lesson

    CERN Document Server

    Barceló, Carlos; Liberati, Stefano

    2010-01-01

    The question of whether it is possible or not to surpass the speed of light is already centennial. The special theory of relativity took the existence of a speed limit as a principle, the light postulate, which has proven to be enormously predictive. Here we discuss some of its twists and turns when general relativity and quantum mechanics come into play. In particular, we discuss one of the most interesting proposals for faster than light travel: warp drives. Even if one succeeded in creating such spacetime structures, it would be still necessary to check whether they would survive to the switching on of quantum matter effects. Here, we show that the quantum back-reaction to warp-drive geometries, created out of an initially flat spacetime, inevitably lead to their destabilization whenever superluminal speeds are attained. We close this investigation speculating the possible significance of this further success of the speed of light postulate.

  13. "OPERA superluminal neutrinos explained by spontaneous emission and stimulated absorption"

    CERN Document Server

    Torrealba, Rafael

    2011-01-01

    In this work it is shown, that for short 3ns neutrino pulses reported by OPERA, a relativistic shape deforming effect of the neutrino distribution function due to spontaneous emission, produces an earlier arrival of 65.8ns in agreement with the reported 62.1ns\\pm 3.7ns, with a RMS of 16.4ns explaining the apparent superluminal effect. It is also shown, that early arrival of long 10500ns neutrinos pulse to Gran Sasso, by 57.8ns with respect to the speed of light, could be explained by a shape deforming effect due to a combination of stimulated absorption and spontaneous emission, while traveling by the decay tunnel that acts as a LASER tube.

  14. Detection of X-ray spectral state transitions in mini-outbursts of black hole transient GRS 1739-278

    Science.gov (United States)

    Yan, Zhen; Yu, Wenfei

    2017-10-01

    We report the detection of the state transitions and hysteresis effect in the two mini-outbursts of the black hole (BH) transient GRS 1739-278 following its 2014 major outburst. The X-ray spectral evolutions in these two mini-outbursts are similar to the major outburst in spite of their peak luminosities and the outburst durations are one order of magnitude lower. We found L_hard{-to-soft} and Lpeak,soft of the mini-outbursts also follow the correlation previously found in other X-ray binaries. L_hard{-to-soft} of the mini-outbursts is still higher than that of the persistent BH binary Cyg X-1, which supports that there is a link between the maximum luminosity a source can reach in the hard state and the corresponding non-stationary accretion represented by substantial rate of change in the mass accretion rate during flares/outbursts. The detected luminosity range of these two mini-outbursts is roughly in 3.5 × 10-5 to 0.015 (D/7.5 kpc)2(M/8M⊙) LEdd. The X-ray spectra of other BH transients at such low luminosities are usually dominated by a power-law component, and an anti-correlation is observed between the photon index and the X-ray luminosity below 1 per cent LEdd. So, the detection of X-ray spectral state transitions indicates that the accretion flow evolution in these two mini-outbursts of GRS 1739-278 are different from other BH systems at such low-luminosity regime.

  15. GRS 1915+105 as a Galactic Analog of a Fanaroff-Riley II Quasar

    CERN Document Server

    Punsly, Brian

    2013-01-01

    We study the long term time averaged kinetic luminosity, $\\bar{Q}$, of the major flares of the Galactic microquasar GRS 1915+105 and the relationship to the intrinsic X-ray (bolometric) luminosity, $L_{\\mathrm{bol}}$, and scale it to that of a complete sample of SDSS/FIRST FR II quasars. If the scale invariance hypothesis for black holes (BHs) holds then we show that the expected distribution in the $\\bar{Q}$ - $L_{\\mathrm{bol}}$ scatter plane of GRS 1915+105 is consistent with FR II quasars for distances D = 10.7 - 11 kpc. We compare the specific values of kinetic luminosity and $L_{\\mathrm{bol}}$ during flares of GRS 1915+105 to that predicted by several 3-D MHD simulations of BH accretion flows with relativistic ejections. If FR II quasars are a scaled up version of GRS 1915+105, the data are consistent with numerical models when they contain an ergospheric disk jet and the BH spin is $a/M= 0.99$ or $a/M=0.998$ (we estimate $a/M>0.984$). In the framework of scale invariance of BHs, our results may imply th...

  16. GRS 1915+105 AS A GALACTIC ANALOG OF A FANAROFF-RILEY II QUASAR

    Energy Technology Data Exchange (ETDEWEB)

    Punsly, Brian [1415 Granvia Altamira, Palos Verdes Estates, CA 90274 (United States); Rodriguez, Jerome, E-mail: brian.punsly1@verizon.net, E-mail: brian.punsly@comdev-usa.com [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU SAp, F-91191 Gif-sur-Yvette (France)

    2013-06-20

    We study the long-term time-averaged kinetic luminosity, Q-bar , of the major flares of the Galactic microquasar GRS 1915+105 and the relationship to the intrinsic X-ray (bolometric) luminosity, L{sub bol}, and scale it to that of a complete sample of SDSS/FIRST Fanaroff-Riley (FR) II quasars. If the scale invariance hypothesis for black holes (BHs) holds then we show that the expected distribution in the Q-bar -L{sub bol} scatter plane of GRS 1915+105 is consistent with FR II quasars for distances D = 10.7-11 kpc. We compare the specific values of kinetic luminosity and L{sub bol} during flares of GRS 1915+105 to that predicted by several three-dimensional MHD simulations of BH accretion flows with relativistic ejections. If FR II quasars are a scaled up version of GRS 1915+105, the data are consistent with numerical models when they contain an ergospheric disk jet and the BH spin is a/M = 0.99 or a/M = 0.998 (we estimate a/M > 0.984). In the framework of scale invariance of BHs, our results may imply that FR II quasars also hold rapidly rotating BHs.

  17. Modelling Oscillations in the Jet Emission from Microquasar GRS 1915+105

    CERN Document Server

    Collins, R S; Cox, S J; Collins, Ross S.; Kaiser, Christian R.; Cox, Simon J.

    2003-01-01

    The variability in the infrared to millimetre emission from microquasar GRS 1915+105 is believed to be dominated by the system's relativistic jet. In this paper we develop a time-dependent version of the Blandford & Konigl (1979) jet emission model and apply it to the oscillations in the infrared and millimetre emission from GRS 1915+105 observed by Fender & Pooley (2000). The resulting model provides a reasonable description of the observed flux oscillations from GRS 1915+105. From a fit of the observed time lag between the flux peaks in the infrared and millimetre emission together with the flux normalisation we were able to determine the model parameters for the GRS 1915+105 jet. We find that to achieve the observed flux levels with the model requires an unphysically large electron density within the jet. We therefore conclude that the Blandford & Konigl (1979) model cannot explain these observations, either because it does not provide the correct description of the emission from microquasar je...

  18. NuSTAR spectroscopy of GRS 1915+105: Disk reflection, spin, and connections to jets

    DEFF Research Database (Denmark)

    Miller, J. M.; Parker, M. L.; Fuerst, F.

    2013-01-01

    We report on the results of spectral fits made to a NuSTAR observation of the black hole GRS 1915+105 in a “plateau” state. This state is of special interest because it is similar to the “low/hard” state seen in other black holes, especially in that compact, steady jets are launched in this phase...

  19. Measuring the Spin of GRS 1915+105 with Relativistic Disk Reflection

    Science.gov (United States)

    Blum, J. L.; Miller, J. M.; Fabian, A. C.; Miller, M. C.; Homan, J.; van der Klis, M.; Cackett, E. M.; Reis, R. C.

    2009-11-01

    GRS 1915+105 harbors one of the most massive known stellar black holes in the Galaxy. In 2007 May, we observed GRS 1915+105 for ~117 ks in the low/hard state using Suzaku. We collected and analyzed the data with the Hard X-ray Detector/Positive Intrinsic Negative and X-ray Spectrometer cameras spanning the energy range from 2.3 to 55 keV. Fits to the spectra with simple models reveal strong disk reflection through an Fe K emission line and a Compton backscattering hump. We report constraints on the spin parameter of the black hole in GRS 1915 + 105 using relativistic disk reflection models. The model for the soft X-ray spectrum (i.e., hat{a} = 0.56^{+0.02}_{-0.02} and excludes zero spin at the 4σ level of confidence. The model for the full broadband spectrum suggests that the spin may be higher, \\hat{a} = 0.98^{+0.01}_{-0.01} (1σ confidence), and again excludes zero spin at the 2σ level of confidence. We discuss these results in the context of other spin constraints and inner disk studies in GRS 1915 + 105.

  20. Experimental demonstration of a new radiation mechanism: emission by an oscillating, accelerated, superluminal polarization current

    CERN Document Server

    Ardavan, A; Ardavan, H; Fopma, J; Halliday, D; Hayes, W

    2004-01-01

    We describe the experimental implementation of a superluminal ({\\it i.e.} faster than light {\\it in vacuo}) polarization current distribution that both oscillates and undergoes centripetal acceleration. Theoretical treatments lead one to expect that the radiation emitted from each volume element of such a polarization current will comprise a \\v{C}erenkov-like envelope with two sheets that meet along a cusp. The emission from the experimental machine is in good agreement with these expectations, the combined effect of the volume elements leading to tightly-defined beams of a well-defined geometry, determined by the source speed and trajectory. In addition, over a restricted range of angles, we detect the presence of cusps in the emitted radiation. These are due to the detection over a short time period (in the laboratory frame) of radiation emitted over a considerably longer period of source time. Consequently, the intensity of the radiation at these angles was observed to decline more slowly with increasing d...

  1. GRO J0422+32 = GRS 0417+335

    DEFF Research Database (Denmark)

    Castro-Tirado, A. J.; Brandt, Søren; Lund, Niels;

    1992-01-01

    A. J. Castro-Tirado, S. Brandt, and N. Lund, Granat WATCH team (Danish Space Research Institute, Lyngby; and Space Research Institute, Moscow), report: "The hard x-ray transient reported by Paciesas et al. on IAUC 5580 has been observed by the WATCH all-sky monitor on Granat. The source intensity...

  2. Revealing the binary origin of Type Ic superluminous supernovae through nebular hydrogen emission

    CERN Document Server

    Moriya, Takashi J; Mackey, Jonathan; Chen, Ting-Wan; Langer, Norbert

    2015-01-01

    We propose that nebular Halpha emission as detected in the Type Ic superluminous supernova iPTF13ehe stems from matter which is stripped from a companion star when the supernova ejecta collide with it. The temporal evolution, the line broadening, and the overall blueshift of the emission are consistent with this interpretation. We scale the nebular Halpha luminosity predicted for Type Ia supernovae in single-degenerate systems to derive the stripped mass required to explain the Halpha luminosity of iPTF13ehe. We find a stripped mass of 0.1 - 0.9 solar masses, assuming that the supernova luminosity is powered by radioactivity or magnetar spin down. Because a central heating source is required to excite the Halpha emission, an interaction-powered model is not favored for iPTF13ehe. We derive a companion mass of more than 20 solar masses and a binary separation of less than about 20 companion radii based on the stripping efficiency during the collision, indicating that the supernova progenitor and the companion ...

  3. Superluminal non-ballistic jet swing in the quasar NRAO 150 revealed by mm-VLBI

    CERN Document Server

    Agudo, I; Krichbaum, T P; Marscher, A P; Gonidakis, I; Diamond, P J; Perucho, M; Alef, W; Graham, D A; Witzel, A; Zensus, J A; Bremer, M; Acosta-Pulido, J A; Barrena, R

    2007-01-01

    NRAO 150 -a compact and bright radio to mm source showing core/jet structure- has been recently identified as a quasar at redshift z=1.52 through a near-IR spectral observation. To study the jet kinematics on the smallest accessible scales and to compute the first estimates of its basic physical properties, we have analysed the ultra-high-resolution images from a new monitoring program at 86 GHz and 43 GHz with the GMVA and the VLBA, respectively. An additional archival and calibration VLBA data set, covering from 1997 to 2007, has been used. Our data shows an extreme projected counter-clock-wise jet position angle swing at an angular rate of up to ~11 deg./yr within the inner ~31 pc of the jet, which is associated with a non-ballistic superluminal motion of the jet within this region. The results suggest that the magnetic field could play an important role in the dynamics of the jet in NRAO 150, which is supported by the large values of the magnetic field strength obtained from our first estimates. The extre...

  4. Pulsational Pair-instability Model for Superluminous Supernova PTF12dam: Interaction and Radioactive Decay

    Science.gov (United States)

    Tolstov, Alexey; Nomoto, Ken’ichi; Blinnikov, Sergei; Sorokina, Elena; Quimby, Robert; Baklanov, Petr

    2017-02-01

    Being a superluminous supernova, PTF12dam can be explained by a 56Ni-powered model, a magnetar-powered model, or an interaction model. We propose that PTF12dam is a pulsational pair-instability supernova, where the outer envelope of a progenitor is ejected during the pulsations. Thus, it is powered by a double energy source: radioactive decay of 56Ni and a radiative shock in a dense circumstellar medium. To describe multicolor light curves and spectra, we use radiation-hydrodynamics calculations of the STELLA code. We found that light curves are well described in the model with 40 M⊙ ejecta and 20–40 M⊙ circumstellar medium. The ejected 56Ni mass is about 6 M⊙, which results from explosive nucleosynthesis with large explosion energy (2–3) × 1052 erg. In comparison with alternative scenarios of pair-instability supernova and magnetar-powered supernova, in the interaction model, all the observed main photometric characteristics are well reproduced: multicolor light curves, color temperatures, and photospheric velocities.

  5. GRO J0422+32 = GRS 0417+335

    DEFF Research Database (Denmark)

    Castro-Tirado, A. J.; Brandt, Søren; Lund, Niels

    1992-01-01

    , and three times brighter than, the black-hole candidate Cygnus X-1 as observed by OSSE in 1991 June. Significant emission is observed up to about 600 keV, with an average source flux of 1.8 photons cmE-2 sE-1 MeVE-1 at 100 keV. The continuum spectrum between 60 and 600 keV is not compatible with a single...

  6. A sub-solar metallicity is required for superluminous supernova progenitors

    CERN Document Server

    Chen, T -W; Yates, R M; Nicholl, M; Krühler, T; Schady, P; Dennefeld, M; Inserra, C

    2016-01-01

    Host galaxy properties provide strong constraints on the stellar progenitors of superluminous supernovae. By comparing a sample of 18 low-redshift superluminous supernova hosts to a volume-limited galaxy population in the local Universe, we show that sub-solar metallici- ties seems to be a requirement. All superluminous supernovae in hosts with high measured gas-phase metallicities are found to explode at large galactocentric radii, indicating that the metallicity at the explosion site is likely lower than the integrated host value. We also confirm that high specific star-formation rates are a feature of superluminous supernova host galaxies, but interpret this as simply a consequence of the anti-correlation between gas-phase metallic- ity and specific star-formation rate and the requirement of on-going star formation to produce young, massive stars greater than ~ 10-20 M_sun . Based on our sample, we propose an upper limit of ~ 0.5 Z_sun for forming superluminous supernova progenitors (assuming an N2 metal- ...

  7. Superluminal reflection and transmission of light pulses via resonant four-wave mixing in cesium vapor.

    Science.gov (United States)

    Jiang, Qichang; Zhang, Yan; Wang, Dan; Ahrens, Sven; Zhang, Junxiang; Zhu, Shiyao

    2016-10-17

    We report the experimental manipulation of the group velocities of reflected and transmitted light pulses in a degenerate two-level atomic system driven by a standing wave, which is created by two counter-propagating light beams of equal frequencies but variable amplitudes. It is shown that the light pulse is reflected with superluminal group velocity while the transmitted pulse propagates from subluminal to superluminal velocities via changing the power of the backward coupling field. We find that the simultaneous superluminal light reflection and transmission can be reached when the power of the backward field becomes closer or equal to the forward power, in this case the periodical absorption modulation for photonic structure is established in atoms. The theoretical discussion shows that the anomalous dispersion associated with a resonant absorption dip within the gain peak due to four-wave mixing leads to the superluminal reflection, while the varying dispersion from normal to anomalous at transparency, transparency within absorption, and electromagnetically induced absorption windows leads to the subluminal to superluminal transmission.

  8. Gain-assisted superluminal propagation and rotary drag of photon and surface plasmon polaritons

    Science.gov (United States)

    Khan, Naveed; Amin Bacha, Bakht; Iqbal, Azmat; Ur Rahman, Amin; Afaq, A.

    2017-07-01

    Superluminal propagation of light is a well-established phenomenon and has motivated immense research interest that has led to state-of-the-art knowledge and potential applications in the emerging technology of quantum optics and photonics. This study presents a theoretical analysis of the gain-assisted superluminal light propagation in a four-level N -type atomic system by exploiting the scheme of electromagnetically induced gain and superluminal propagation of surface plasmon polaritons (SPPs) along the gain-assisted atomic-metal interface simultaneously. In addition, a theoretical demonstration is presented on the comparison between Fresnel's rotary photon drag and SPP drag in view of light polarization state rotation by rotating the coherent atomic medium and the atomic-metal interface, respectively. Analogous to photon drag in the superluminal anomalous dispersion region where light polarization rotation occurs opposite the rotation of the gain-assisted atomic medium, the rotation of the atomic-metal interface also rotates the polarization state of SPPs opposite the rotation of the interface. This further confirms the superluminal nature of SPPs propagating along the interface with negative group velocity. Rabi frequencies of the control and pump fields considerably modify both photon and SPP drag coefficients. Metal conductivity also controls SPP propagation.

  9. Swift broad band observations of the Black Hole transient GRS 1716-249

    Science.gov (United States)

    Del Santo, Melania; D'Ai', Antonino; Bassi, Tiziana; Segreto, Alberto; Belloni, Tomaso; Cusumano, Giancarlo; La Parola, Valentina

    2017-02-01

    We report on Swift observations of the ongoing outburst of the Black Hole Transient (BHT) GRS 1716-249 (ATel #9876, #9895). We analyzed both XRT and BAT data of three Swift ToO pointings performed on 2017 January 28, 29 and 30 (Target ID 34924, segments 1, 2, 3). The XRT count rate is about 90 count/s and therefore the observations have been performed in window-timing mode.

  10. GRS constraints on the character of possible ancient oceans on Mars: consistencies with Earth analogues

    OpenAIRE

    James M. Dohm; Baker, Victor R.; Boynton, William V.; González Fairén, Alberto; Ferris, Justin C.; Finch, Michael; Furfaro, Roberto; Hare, Trent M.; Janes, Daniel M.; Kargel, Jeffrey S.; Karunatillake, Suniti; Keller, John; Kerry, Kris; Kim, Kyeong; Komatsu, Goro

    2007-01-01

    The Gamma Ray Spectrometer (GRS) has revealed elemental distributions of potassium (K), thorium (Th), and iron (Fe) on Mars that require fractionation of K (and possibly the others) consistent with aqueous weathering, transport, sorting, and deposition in the northern plains basins, as well as first-order geomorphological boundaries identified as putative shorelines. The elemental abundances occur in patterns consistent with deposition of weathered materials (salts and clastic minerals) and w...

  11. Optical spectroscopy of the microquasar GRS 1758-258: a possible intermediate mass system?

    Science.gov (United States)

    Martí, Josep; Luque-Escamilla, Pedro L.; Muñoz-Arjonilla, Álvaro J.

    2016-11-01

    Context. GRS 1758-258 is one of two prototypical microquasars towards the Galactic center direction discovered almost a quarter of a century ago. The system remains poorly studied in the optical domain due to its counterpart being a very faint and absorbed target in a crowded region of the sky. Aims: Our aim is to investigate GRS 1758-258 in order to shed light on the nature of the stellar binary components. In particular, the main physical parameters of the donor star, such as the mass or the spectral type, are not yet well constrained. Methods: GRS 1758-258 has remained so far elusive to optical spectroscopy owing to its observational difficulties. Here, we use this traditional tool of stellar astronomy at low spectral resolution with a 10 m class telescope and a long slit spectrograph. Results: An improved spectrum is obtained as compared to previous work. The quality of the data does not allow the detection of emission or absorption features but, nevertheless, we manage to partially achieve our aims comparing the de-reddened continuum with the spectral energy distribution expected from an irradiated disc model and different donor star templates. Conclusions: We tentatively propose that GRS 1758-258 does not host a giant star companion. Instead, a main sequence star with mid-A spectral type appears to better agree with our data. The main impacts of this finding are the possibility that we are dealing with an intermediate mass system and, in this case, the prediction of an orbital period significantly shorter than previously proposed.

  12. Swift broad band observations of the Black Hole transient GRS 1716-249

    Science.gov (United States)

    Del Santo, Melania; D'Ai', Antonino; Bassi, Tiziana; Segreto, Alberto; Belloni, Tomaso; Cusumano, Giancarlo; Parola, Valentina La

    2017-02-01

    We report on Swift observations of the ongoing outburst of the Black Hole Transient (BHT) GRS 1716-249 (ATel #9876, #9895). We analyzed both XRT and BAT data of three Swift ToO pointings performed on 2017 January 28, 29 and 30 (Target ID 34924, segments 1, 2, 3). The XRT count rate is about 90 count/s and therefore the observations have been performed in window-timing mode.

  13. Super-luminous supernovae: 56Ni power versus magnetar radiation

    CERN Document Server

    Dessart, Luc; Waldman, Roni; Livne, Eli; Blondin, Stephane

    2012-01-01

    Much uncertainty surrounds the origin of super-luminous supernovae (SNe). Motivated by the discovery of the Type Ic SN2007bi, we study its proposed association with a pair-instability SN (PISN). We compute stellar-evolution models for primordial ~200Msun stars, simulating the implosion/explosion due to the pair-production instability, and use them as inputs for detailed non-LTE time-dependent radiative-transfer simulations that include non-local energy deposition and non-thermal processes. We retrieve the basic morphology of PISN light curves from red-supergiant, blue-supergiant, and Wolf-Rayet (WR) star progenitors. Although we confirm that a progenitor 100Msun helium core (PISN model He100) fits well the SN2007bi light curve, the low ratios of its kinetic energy and 56Ni mass to the ejecta mass, similar to standard core-collapse SNe, conspire to produce cool photospheres, red spectra subject to strong line blanketing, and narrow line profiles, all conflicting with SN2007bi observations. He-core models of in...

  14. Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap

    CERN Document Server

    Arcavi, Iair; Howell, D Andrew; Bildsten, Lars; Leloudas, Giorgos; Hardin, Delphine; Prajs, Szymon; Perley, Daniel A; Svirski, Gilad; Gal-Yam, Avishay; Katz, Boaz; McCully, Curtis; Cenko, S Bradley; Lidman, Chris; Sullivan, Mark; Valenti, Stefano; Astier, Pierre; Balland, Cristophe; Carlberg, Ray G; Conley, Alex; Fouchez, Dominique; Guy, Julien; Pain, Reynald; Palanque-Delabrouille, Nathalie; Perrett, Kathy; Pritchet, Chris J; Regnault, Nicolas; Rich, James; Ruhlmann-Kleider, Vanina

    2015-01-01

    We present observations of four rapidly rising (t_{rise}~10d) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (M_{peak}~-20) - one discovered and followed by the Palomar Transient Factory (PTF) and three by the Supernova Legacy Survey (SNLS). The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as a Type II SN due to broad Halpha emission, but an unusual absorption feature, which can be interpreted as either high velocity Halpha (though deeper than in previously known cases) or Si II (as seen in Type Ia SNe), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM) and magnetar spindown can not r...

  15. Spectropolarimetry of Superluminous Supernovae: Insight into Their Geometry

    Science.gov (United States)

    Inserra, C.; Bulla, M.; Sim, S. A.; Smartt, S. J.

    2016-11-01

    We present the first spectropolarimetric observations of a hydrogen-free superluminous supernova (SLSN) at z = 0.1136, namely SN 2015bn. The transient shows significant polarization at both of the observed epochs: one 24 days before maximum light in the rest-frame, and the other at 27 days after peak luminosity. Analysis of the Q - U plane suggests the presence of a dominant axis and no physical departure from the main axis at either epoch. The polarization spectrum along the dominant axis is characterized by a strong wavelength dependence and an increase in the signal from the first to the second epoch. We use a Monte Carlo code to demonstrate that these properties are consistent with a simple toy model that adopts an axisymmetric ellipsoidal configuration for the ejecta. We find that the wavelength dependence of the polarization is possibly due to a strong wavelength dependence in the line opacity, while the higher level of polarization at the second epoch is a consequence of the increase in the asphericity of the inner layers of the ejecta or the fact that the photosphere recedes into less spherical layers. The geometry of the SLSN is similar to that of stripped-envelope core-collapse SNe connected to GRB, while the overall evolution of the ejecta shape could be consistent with a central engine.

  16. Spectral evolution of superluminal components in parsec-scale jets

    CERN Document Server

    Mimica, P; Agudo, I; Martí, J M; Gómez, J L; Miralles, J A

    2008-01-01

    (Abridged) We present numerical simulations of the spectral evolution and radio emission of superluminal components in relativistic jets. We have developed an algorithm (SPEV) for the transport of a population of non-thermal particles (NTPs). For very large values of the ratio of gas pressure to magnetic field energy density ($\\sim 6\\times 10^4$), quiescent over-pressured jet models show substantial spectral evolution compared to models whithout radiative losses. Larger values of the magnetic field yield much shorter jets. Larger magnetic fields result in shorter losses-dominated regimes, with a rapid and intense radiation of energy. We also show that jets with a positive photon spectral index may result if the lower limit $\\gamma_min$ of the NTP energy distribution is placed close or above a threshold $\\gamma_M$, where the synchrotron function R has its maximum. A temporary increase of the Lorentz factor at the jet inlet produces a traveling perturbation that appears in the synthetic maps as a radio componen...

  17. The Trails of Superluminal Jet Components in 3C 111

    Science.gov (United States)

    Kadler, M.; Ros, E.; Perucho, M.; Kovalev, Y. Y.; Homan, D. C.; Agudo, I.; Kellermann, K. I.; Aller, M. F.; Aller, H. D.; Lister, M. L.; Zensus, J. A.

    2007-01-01

    The parsec-scale radio jet of the broad-line radio galaxy 3C 111 has been monitored since 1995 as part of the 2cm Survey and MOJAVE monitoring observations conducted with the VLBA. Here, we present results from 18 epochs of VLBA observations of 3C 111 and from 18 years of radio flux density monitoring observations conducted at the University of Michigan. A major radio flux-density outburst of 3C 111 occurred in 1996 and was followed by a particularly bright plasma ejection associated with a superluminal jet component. This major event allows us to study a variety of processes associated with outbursts of radio-loud AGN in much greater detail than possible in other cases: the primary perturbation gives rise to the formation of a forward and a backward-shock, which both evolve in characteristically different ways and allow us to draw conclusions about the workflow of jet-production events; the expansion, acceleration and recollimation of the ejected jet plasma in an environment with steep pressure and density gradients are revealed; trailing components are formed in the wake of the primary perturbation as a result of Kelvin- Helmholtz instabilities from the interaction of the jet with the external medium. The jet-medium interaction is further scrutinized by the linear-polarization signature of jet components traveling along the jet and passing a region of steep pressure/density gradients.

  18. The Trails of Superluminal Jet Components in 3C111

    CERN Document Server

    Kadler, M; Perucho, M; Kovalev, Y Y; Homan, D C; Agudo, I; Kellermann, K I; Aller, M F; Aller, H D; Lister, M L; Zensus, J A

    2008-01-01

    In 1996, a major radio flux-density outburst occured in the broad-line radio galaxy 3C111. It was followed by a particularly bright plasma ejection associated with a superluminal jet component, which has shaped the parsec-scale structure of 3C111 for almost a decade. Here, we present results from 18 epochs of Very Long Baseline Array (VLBA) observations conducted since 1995 as part of the VLBA 2 cm Survey and MOJAVE monitoring programs. This major event allows us to study a variety of processes associated with outbursts of radio-loud AGN in much greater detail than has been possible in other cases: the primary perturbation gives rise to the formation of a leading and a following component, which are interpreted as a forward and a backward-shock. Both components evolve in characteristically different ways and allow us to draw conclusions about the work flow of jet-production events; the expansion, acceleration and recollimation of the ejected jet plasma in an environment with steep pressure and density gradien...

  19. Zooming In on the Progenitors of Superluminous Supernovae With HST

    CERN Document Server

    Lunnan, R; Berger, E; Rest, A; Fong, W; Scolnic, D; Jones, D; Soderberg, A M; Challis, P M; Drout, M R; Foley, R J; Huber, M E; Kirshner, R P; Leibler, C; Marion, G H; McCrum, M; Milisavljevic, D; Narayan, G; Sanders, N E; Smartt, S J; Smith, K W; Tonry, J L; Burgett, W S; Chambers, K C; Flewelling, H; Kudritzki, R -P; Wainscoat, R J; Waters, C

    2014-01-01

    We present Hubble Space Telescope rest-frame ultraviolet imaging of the host galaxies of 16 hydrogen-poor superluminous supernovae (SLSNe), including 11 events from the Pan-STARRS Medium Deep Survey. Taking advantage of the superb angular resolution of HST, we characterize the galaxies' morphological properties, sizes and star formation rate densities. We determine the SN locations within the host galaxies through precise astrometric matching, and measure physical and host-normalized offsets, as well as the SN positions within the cumulative distribution of UV light pixel brightness. We find that the host galaxies of H-poor SLSNe are irregular, compact dwarf galaxies, with a median half-light radius of just 0.9 kpc. The UV-derived star formation rate densities are high ( ~ 0.1 M_sun/yr/kpc^2), suggesting that SLSNe form in overdense environments. Their locations trace the UV light of their host galaxies, with a distribution intermediate between that of LGRBs (which are strongly clustered on the brightest regi...

  20. On the nature of Hydrogen-rich Superluminous Supernovae

    CERN Document Server

    Inserra, C; Gall, E E E; Leloudas, G; Chen, T -W; Schulze, S; Jerkstarnd, A; Nicholl, M; Anderson, J P; Arcavi, I; Benetti, S; Cartier, R A; Childress, M; Della Valle, M; Flewelling, H; Fraser, M; Gal-Yam, A; Gutierrez, C P; Hosseinzadeh, G; Howell, D A; Huber, M; Kankare, E; Magnier, E A; Maguire, K; McCully, C; Prajs, S; Primak, N; Scalzo, R; Schmidt, B P; Smith, K W; Tucker, B E; Valenti, S; Wilman, M; Young, D R; Yuan, F

    2016-01-01

    We present observational data for two hydrogen-rich superluminous supernovae (SLSNe), namely SN 2013hx and PS15br. These objects, together with SN 2008es are the only SLSNe showing a distinct, broad H$\\alpha$ feature during the photospheric phase and also do not show any clear sign of interaction between fast moving ejecta and circumstellar shells in their early spectra. Therefore we classify them as SLSN II as distinct from the known class of SLSN IIn. Both transients show a slow decline at later times, and monitoring of SN 2013hx out to 300 days after explosion indicates that the luminosity in this later phase does have a contribution from interaction. We detect strong, multi-component H$\\alpha$ emission at 240 days past maximum which we interpret as an indication of interaction of the ejecta with an asymmetric, clumpy circumstellar material. The spectra and photometric evolution of the two objects are similar to some bright type II (or type IIL) supernovae, although they have much higher luminosity and evo...

  1. 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...

  2. Spectropolarimetry of superluminous supernovae: insight into their geometry

    CERN Document Server

    Inserra, C; Sim, S A; Smartt, S J

    2016-01-01

    We present the first spectropolarimetric observations of a hydrogen-free superluminous supernova at z=0.1136, namely SN 2015bn. The transient shows significant polarization at both the observed epochs: one 24 days before maximum light in the rest-frame, and the subsequent at 27 days after peak luminosity. Analysis of the Q-U plane suggests the presence of a dominant axis and no physical departure from the main axis at either epoch. The polarization spectrum along the dominant axis is characterized by a strong wavelength dependence and an increase in the signal from the first to the second epoch. We use a Monte Carlo code to demonstrate that these properties are consistent with a simple toy model that adopts an axi-symmetric ellipsoidal configuration for the ejecta. We find that the wavelength dependence of the polarisation is possibly due to a strong wavelength dependence in the line opacity, while the higher level of polarisation at the second epoch is a consequence of the increase in the asphericity of the ...

  3. Long-duration superluminous supernovae at late times

    CERN Document Server

    Jerkstrand, A; Inserra, C; Nicholl, M; Chen, T -W; Krühler, T; Sollerman, J; Taubenberger, S; Gal-Yam, A; Kankare, E; Maguire, K; Fraser, M; Valenti, S; Sullivan, M; Cartier, R; Young, D R

    2016-01-01

    We present nebular-phase observations and spectral models of Type Ic superluminous supernovae. LSQ14an and SN 2015bn both display late-time spectra similar to SN 2007bi, and the class shows strong similarity with broad-lined Type Ic SNe such as SN 1998bw. Near-infrared observations of SN 2015bn at +315d show a strong Ca II triplet, O I 9263, O I 1.13 micron and Mg I 1.50 micron, but no strong He, Si, or S emission. The high Ca II NIR/[Ca II] 7291, 7323 ratio of 2 indicates a high electron density of n_e >~ 10^8 cm^{-3}. Spectral models of oxygen-zone emission are investigated to put constraints on the emitting region. Models require M(O) >~ 10 Msun to produce enough [O I] 6300, 6364 luminosity to match observed levels, irrespective of the powering situation and the density. This is an argument against shell collisions from pair-instability pulsations for explaining the powering, as these shells are limited to a few solar masses in published models. The high oxygen-zone mass, supported by high estimated magnes...

  4. Rates of Superluminous Supernovae at z~0.2

    CERN Document Server

    Quimby, Robert M; Akerlof, Car; Wheeler, J Craig

    2013-01-01

    We calculate the volumetric rate of superluminous supernovae (SLSNe) based on 5 events discovered with the ROTSE-IIIb telescope. We gather light curves of 19 events from the literature and our own unpublished data and employ crude k-corrections to constrain the pseudo-absolute magnitude distributions in the rest frame ROTSE-IIIb (unfiltered) band pass for both the hydrogen poor (SLSN-I) and hydrogen rich (SLSN-II) populations. We find that the peak magnitudes of the available SLSN-I are narrowly distributed ($M = -21.7 \\pm 0.4$) in our unfiltered band pass and may suggest an even tighter intrinsic distribution when the effects of dust are considered, although the sample may be skewed by selection and publication biases. The presence of OII features near maximum light may uniquely signal a high luminosity event, and we suggest further observational and theoretical work is warranted to assess the possible utility of such SN 2005ap-like SLSN-I as distance indicators. Using the pseudo-absolute magnitude distribut...

  5. RAPIDLY RISING TRANSIENTS IN THE SUPERNOVA—SUPERLUMINOUS SUPERNOVA GAP

    Energy Technology Data Exchange (ETDEWEB)

    Arcavi, Iair; Howell, D. Andrew [Las Cumbres Observatory Global Telescope, 6740 Cortona Dr., Suite 102, Goleta, CA 93111 (United States); Wolf, William M. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Bildsten, Lars; McCully, Curtis; Valenti, Stefano [Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States); Leloudas, Giorgos; Gal-Yam, Avishay; Katz, Boaz [Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot, 76100 (Israel); Hardin, Delphine; Astier, Pierre; Balland, Cristophe [LPNHE, CNRS-IN2P3 and University of Paris VI and VII, F-75005 Paris (France); Prajs, Szymon; Sullivan, Mark [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Perley, Daniel A. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Svirski, Gilad [Racah Institute for Physics, The Hebrew University, Jerusalem 91904 (Israel); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Lidman, Chris [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Carlberg, Ray G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada); Conley, Alex, E-mail: iarcavi@lcogt.net [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-389 (United States); and others

    2016-03-01

    We present observations of four rapidly rising (t{sub rise} ≈ 10 days) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (M{sub peak} ≈ −20)—one discovered and followed by the Palomar Transient Factory (PTF) and three by the Supernova Legacy Survey. The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma-ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as an SN II due to broad Hα emission, but an unusual absorption feature, which can be interpreted as either high velocity Hα (though deeper than in previously known cases) or Si ii (as seen in SNe Ia), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM), and magnetar spin down cannot readily explain the observations. We consider the possibility that a “Type 1.5 SN” scenario could be the origin of our events. More detailed models for these kinds of transients and more constraining observations of future such events should help to better determine their nature.

  6. What do the remnants of superluminous supernovae look like?

    Science.gov (United States)

    Leloudas, G.

    2016-06-01

    The remnants of core-collapse supernovae often present significant asymmetries while those of thermonuclear supernovae are, more or less, spherically symmetric. As superluminous supernovae (SLSN) do not occur in Milky Way-type galaxies (they prefer metal-poor starburst dwarfs), our chances of studying directly a SLSN remnant are very limited, except perhaps in the Magellanic clouds. Therefore, the only way of probing the SLSN geometry, and thus identifying potential SLSN remnant candidates, is through polarimetry of the explosions themselves. I will present the first polarimetric observations of SLSNe obtained through a dedicated ToO program at the VLT. LSQ14mo is a SLSN-I that showed only a very limited degree of polarisation (P = 0.52%), which corresponds to an upper limit of 10% in the photosphere asphericity. In addition, this signal can be entirely due to interstellar polarisation in the host galaxy. This is perhaps surprising as the leading models for H-poor SLSNe involve a magnetar or CSM interaction, i.e. configurations that are not expected to be spherically symmetric. Observations of a SLSN-II yielded a more significant degree of polarisation, while preliminary analysis for a SLSN-R reveals similarly low levels of asphericity as for LSQ14mo.

  7. PETER: A Hardware Simulator for the Test Mass-GRS System of LISA Pathfinder

    Science.gov (United States)

    Marconi, L.; Stanga, R.; Bassan, M.; De Marchi, F.; Pucacco, G.; Visco, M.; Di Fiore, L.; De Rosa, R.; Garufi, F.

    2013-01-01

    Each LISA PathFinder test mass (TM) will be sensitive to forces along all its 6 Degrees of Freedom (DoFs). Extensive ground testing is required in order to evaluate the influence of cross-talks from the read-out and actuator channels. In the INFN laboratory of Firenze we have developed a facility for a good representation of the free fall conditions of the TM on flight. A hollow replica of a TM hanging from a double torsion pendulum can move inside a Gravitational Reference Sensor (GRS) with quasi free fall condition on two Dofs, in the frequency band (0.1 ÷ 100)mHz. On both DoFs, the target residual accelerations (yet to be achieved) at the low end frequency range are ≤ 3 × 10-13ms-2, limited by the thermal noise of the fibres. At higher frequencies, the sensitivity is limited by the readout noise of the readout, a replica of the flight electronics. After a long commissioning, we are now in operating conditions, and can carry out a series of experiments to better qualify the interaction between TM and GRS. In this paper we will show some significant qualification measurements and a first scientific measurements, i.e. the measurement and compensation of the DC bias in the GRS using two independent channels, as well as a measurement of the residual acceleration of the translational DoF, with the feedback loop closed on the rotational one, and viceversa.

  8. Optical spectroscopy of the microquasar GRS 1758-258: a possible intermediate mass system?

    CERN Document Server

    Martí, Josep; Muñoz-Arjonilla, Álvaro J

    2016-01-01

    Context. GRS 1758-258 is one of two prototypical microquasars towards the Galactic Center direction discovered almost a quarter of a century ago. The system remains poorly studied in the optical domain due to its counterpart being a very faint and absorbed target in a crowded region of the sky. Aims. Our aim is to investigate GRS 1758-258 in order to shed light on the nature of the stellar binary components. In particular, the main physical parameters of the donor star, such as the mass or the spectral type, are not yet well constrained. Methods. GRS 1758-258 has remained so far elusive to optical spectroscopy owing to its observational difficulties. Here, we use this traditional tool of stellar astronomy at low spectral resolution with a 10 m class telescope and a long slit spectrograph. Results. An improved spectrum is obtained as compared to previous work. The quality of the data does not allow the detection of emission or absorption features but, nevertheless, we manage to partially achieve our aims compa...

  9. NuSTAR OBSERVATION OF A TYPE I X-RAY BURST FROM GRS 1741.9-2853

    Energy Technology Data Exchange (ETDEWEB)

    Barrière, Nicolas M.; Krivonos, Roman; Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Bachetti, Matteo [Institut de Recherche en Astrophysique et Plantologie, UMR 5277, Toulouse (France); Chakrabarty, Deepto [MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Christensen, Finn E. [National Space Institute, Technical University of Denmark, Copenhagen (Denmark); Hailey, Charles J.; Mori, Kaya [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Harrison, Fiona A. [Cahill Center for Astronomy and Astrophysics, Caltech, Pasadena, CA 91125 (United States); Hong, Jaesub [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, William W., E-mail: barriere@ssl.berkeley.edu [X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2015-02-01

    We report on two NuSTAR observations of GRS 1741.9-2853, a faint neutron star (NS) low-mass X-ray binary burster located 10' away from the Galactic center. NuSTAR detected the source serendipitously as it was emerging from quiescence: its luminosity was 6 × 10{sup 34} erg s{sup –1} on 2013 July 31 and 5 × 10{sup 35} erg s{sup –1} in a second observation on 2013 August 3. A bright, 800 s long, H-triggered mixed H/He thermonuclear Type I burst with mild photospheric radius expansion (PRE) was present during the second observation. Assuming that the luminosity during the PRE was at the Eddington level, an H mass fraction X = 0.7 in the atmosphere, and an NS mass M = 1.4 M {sub ☉}, we determine a new lower limit on the distance for this source of 6.3 ± 0.5 kpc. Combining with previous upper limits, this places GRS 1741.9-2853 at a distance of 7 kpc. Energy independent (achromatic) variability is observed during the cooling of the NS, which could result from the disturbance of the inner accretion disk by the burst. The large dynamic range of this burst reveals a long power-law decay tail. We also detect, at a 95.6% confidence level (1.7σ), a narrow absorption line at 5.46 ± 0.10 keV during the PRE phase of the burst, reminiscent of the detection by Waki et al. We propose that the line, if real, is formed in the wind above the photosphere of the NS by a resonant Kα transition from H-like Cr gravitationally redshifted by a factor 1 + z = 1.09, corresponding to a radius range of 29.0-41.4 km for a mass range of 1.4-2.0 M {sub ☉}.

  10. Comment on: Gain-assisted superluminal light propagation through a Bose-Einstein condensate cavity system

    Science.gov (United States)

    Macke, Bruno; Ségard, Bernard

    2016-09-01

    In a recent theoretical article [S.H. Kazemi, S. Ghanbari, M. Mahmoudi, Eur. Phys. J. D 70, 1 (2016)], Kazemi et al. claim to have demonstrated superluminal light transmission in an optomechanical system where a Bose-Einstein condensate serves as the mechanical oscillator. In fact the superluminal propagation is only inferred from the existence of a minimum of transmission of the system at the probe frequency. This condition is not sufficient and we show that, in all the cases where superluminal propagation is claimed by Kazemi et al., the propagation is in reality subluminal. Moreover, we point out that the system under consideration is not minimum-phase-shift. The Kramers-Kronig relations then only fix a lower limit to the group delay and we show that these two quantities have sometimes opposite signs.

  11. Inverse Doppler shift and control field as coherence generators for the stability in superluminal light

    Science.gov (United States)

    Ghafoor, Fazal; Bacha, Bakht Amin; Khan, Salman

    2015-05-01

    A gain-based four-level atomic medium for the stability in superluminal light propagation using control field and inverse Doppler shift as coherence generators is studied. In regimes of weak and strong control field, a broadband and multiple controllable transparency windows are, respectively, identified with significantly enhanced group indices. The observed Doppler effect for the class of high atomic velocity of the medium is counterintuitive in comparison to the effect of the class of low atomic velocity. The intensity of each of the two pump fields is kept less than the optimum limit reported in [M. D. Stenner and D. J. Gauthier, Phys. Rev. A 67, 063801 (2003), 10.1103/PhysRevA.67.063801] for stability in the superluminal light pulse. Consequently, superluminal stable domains with the generated coherence are explored.

  12. Comment on "Gain-assisted superluminal light propagation through a Bose-Einstein condensate cavity system"

    CERN Document Server

    Macke, Bruno

    2016-01-01

    In a recent theoretical article [Eur. Phys. J. D 70, 1 (2016)], Kazemi et al. claim to have demonstrated superluminal light transmission in an optomechanical system where a Bose-Einstein condensate serves as the mechanical oscillator. In fact the superluminal propagation is only inferred from the existence of a minimum of transmission of the system at the probe frequency. This condition is not sufficient and we show that, in all the cases where superluminal propagation is claimed by Kazemi et al., the propagation is in reality subluminal. Moreover, we point out that the system under consideration is not minimum-phase-shift. The Kramers-Kronig relations then only fix a lower limit to the group delay and we show that these two quantities have sometimes opposite signs.

  13. Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects Superluminal Motion of Gamma-Ray Bright Blazars

    CERN Document Server

    Jorstad, S G; Mattox, J R; Wehrle, A E; Bloom, S D; Yurchenko, A V; Jorstad, Svetlana G; Marscher, Alan P; Mattox, John R; Wehrle, Ann E; Bloom, Steven D; Yurchenko, Alexei V

    2001-01-01

    We present the results of a program to monitor the structure of the radio emission in 42 $\\gamma$-ray bright blazars (31 quasars and 11 BL Lac objects) with the VLBA at 43, 22, and occasionally 15 and 8.4 GHz, over the period from November 1993 to July 1997. We determine proper motions in 33 sources and find that the apparent superluminal motions in $\\gamma$-ray sources are much faster than for the general population of bright compact radio sources. This follows the strong dependence of the $\\gamma$-ray flux on the level of relativistic beaming for both external-radiation Compton and synchrotron self-Compton emission. There is a positive correlation (correlation coefficient $r$=0.45) between the flux density of the VLBI core and the $\\gamma$-ray flux and a moderate correlation (partial correlation coefficient $r$=0.31) between $\\gamma$-ray apparent luminosity and superluminal velocities of jet components, as expected if the $\\gamma$-ray emission originates in a very compact region of the relativistic jet and ...

  14. Superluminal motions? A bird-eye view of the experimental situation

    CERN Document Server

    Recami, E

    2001-01-01

    In this article (after some brief theoretical considerations) a bird-eye view is presented -with the help of nine figures- of the various experimental sectors of physics in which Superluminal motions seem to appear. In particular, a panorama is presented of the experiments with evanescent waves and/or tunnelling photons, and with the "localized Superluminal solutions" to the Maxwell equations (e.g., with the so-called X-shaped ones). The present paper is sketchy, but is followed by a large enough bibliography to allow the interested reader deepening the preferred topic.

  15. GRS 1915+105 in "Soft State": Nature of Accretion Disk Wind and Origin of X-Ray Emission

    CERN Document Server

    Ueda, Yoshihiro; Remillard, Ronald

    2009-01-01

    We present the results from simultaneous Chandra HETGS and RXTE observations of the microquasar GRS 1915+105 in its quasi-stable "soft state" (or State A) performed on 2007 August 14, several days after the state transition from "hard state" (State C). The X-ray flux increased with spectral hardening around the middle of the Chandra observation, after which the 67 Hz QPO became significant. The HETGS spectra reveal at least 32 narrow absorption lines from highly ionized ions including Ne, Mg, Si, S, Ar, Ca, Cr, Mn, Fe, whose features are the deepest among those ever observed with Chandra from this source. We find that the absorber has outflow velocities of ~150 and ~500 km s^{-1} with a line-of-sight velocity dispersion of ~70 and ~200 km s^{-1} for the Si XIV and Fe XXVI ions, respectively. The larger velocity and its dispersion in heavier ions indicate that the wind has a non-uniform dynamical structure along the line-of-sight. The location of the absorber is estimated at ~(1-3)x10^5 r_g (r_g is the gravita...

  16. Comparison of time/phase lags in the hard state and plateau state of GRS 1915+105

    CERN Document Server

    Pahari, Mayukh; Yadav, J S; Misra, Ranjeev; Uttley, Phil

    2013-01-01

    We investigate the complex behavior of energy- and frequency-dependent time/phase lags in the plateau state and the radio-quiet hard state of GRS 1915+105. In our timing analysis, we find that when the source is faint in the radio, QPOs are observed above 2 Hz and typically exhibit soft lags (soft photons lag hard photons), whereas QPOs in the radio-bright plateau state are found below 2.2 Hz and consistently show hard lags. The phase lag at the QPO frequency is strongly anti-correlated with the QPO frequency, changing sign at 2.2 Hz. However, the phase lag at the frequency of the first harmonic is positive and nearly independent of frequency at at ~0.172 rad, regardless of the radio emission. The lag-energy dependence at the first harmonic is also independent of radio flux. However, the lags at the QPO frequency are negative at all energies during the radio-quiet state, but lags at the QPO frequency during the plateau state are positive at all energies and show a 'reflection-type' evolution of the lag-energy...

  17. AstroSat/LAXPC reveals the high energy variability of GRS 1915+105 in the chi class

    CERN Document Server

    Yadav, J S; Chauhan, Jai Verdhan; Agrawal, P C; Antia, H M; Pahari, Mayukh; Dedhia, Dhiraj; Katoch, Tilak; Madhwani, P; Manchanda, R K; Paul, B; Shah, Parag; Ishwara-Chandra, C H

    2016-01-01

    We present the first quick look analysis of data from nine {\\it AstroSat}'s LAXPC observations of GRS 1915+105 during March 2016 when the source had the characteristics of being in Radio-quiet $\\chi$ class. We find that a simple empirical model of a disk blackbody emission, with Comptonization and a broad Gaussian Iron line can fit the time averaged 3--80 keV spectrum with a systematic uncertainty of 1.5\\% and a background flux uncertainty of 4\\%. A simple deadtime-corrected Poisson noise level spectrum matches well with the observed high frequency power spectra till 50 kHz and as expected the data show no significant high frequency ($> 20$ Hz) features. Energy dependent power spectra reveal a strong low frequency (2 - 8 Hz) Quasi-periodic oscillation (LFQPO) and its harmonic along with broad band noise. The QPO frequency changes rapidly with flux (nearly 4 Hz in ~ 5 hours). With increasing QPO frequency, an excess noise component appears significantly in the high energy regime (> 8 keV). At the QPO frequenci...

  18. Tunable THz Generation by the Interaction of a Super-luminous Laser Pulse with Biased Semiconductor Plasma

    Science.gov (United States)

    Papadopoulos, K.; Zigler, A.

    2006-01-01

    Terahertz (THz) radiation is electromagnetic radiation in the range between several hundred and a few thousand GHz. It covers the gap between fast-wave electronics (millimeter waves) and optics (infrared). This spectral region offers enormous potential for detection of explosives and chemical/biological agents, non-destructive testing of non-metallic structural materials and coatings of aircraft structures, medical imaging, bio-sensing of DNA stretching modes and high-altitude secure communications. The development of these applications has been hindered by the lack of powerful, tunable THz sources with controlled waveform. The need for such sources is accentuated by the strong, but selective absorption of THz radiation during transmission through air with high vapor content. The majority of the current experimental work relies on time-domain spectroscopy using fast electrically biased photoconductive sources in conjunction with femto-second mode-locked Ti:Sapphire lasers. These sources known as Large Aperture Photoconductive Antennas (LAPA) have very limited tunability, relatively low upper bound of power and no bandwidth control. The paper presents a novel source of THz radiation known as Miniature Photoconductive Capacitor Array (MPCA). Experiments demonstrated tunability between .1 - 2 THz, control of the relative bandwidth Δf/f between .5-.01, and controlled pulse length and pulse waveform (temporal shape, chirp, pulse-to-pulse modulation etc.). Direct scaling from the current device indicates efficiency in excess of 30% at 1 THz with 1/f2 scaling at higher frequencies, peak power of 100 kW and average power between .1-1 W. The physics underlying the MPCA is the interaction of a super-luminous ionization front generated by the oblique incidence of a Ti:Sapphire laser pulse on a semiconductor crystal (ZnSe) biased with an alternating electrostatic field, similar to that of a frozen wave generator. It is shown theoretically and experimentally that the

  19. An Ultraviolet Excess in the Superluminous Supernova Gaia16apd Reveals a Powerful Central Engine

    Science.gov (United States)

    Nicholl, M.; Berger, E.; Margutti, R.; Blanchard, P. K.; Milisavljevic, D.; Challis, P.; Metzger, B. D.; Chornock, R.

    2017-01-01

    Since the discovery of superluminous supernovae (SLSNe) in the last decade, it has been known that these events exhibit bluer spectral energy distributions than other supernova subtypes, with significant output in the ultraviolet. However, the event Gaia16apd seems to outshine even the other SLSNe at rest-frame wavelengths below ∼3000 Å. Yan et al. have recently presented HST UV spectra and attributed the UV flux to low iron-group abundance in the outer ejecta, and hence reduced line blanketing. Here, we present UV and optical light curves over a longer baseline in time, revealing a rapid decline at UV wavelengths despite a typical optical evolution. Combining the published UV spectra with our own optical data, we demonstrate that Gaia16apd has a much hotter continuum than virtually any SLSN at maximum light, but it cools rapidly thereafter and is indistinguishable from the others by ∼10–15 days after peak. Comparing the equivalent widths of UV absorption lines with those of other events, we show that the excess UV continuum is a result of a more powerful central power source, rather than a lack of UV absorption relative to other SLSNe or an additional component from interaction with the surrounding medium. These findings strongly support the central-engine hypothesis for hydrogen-poor SLSNe. An explosion ejecting Mej = 4.8(0.2/κ) M⊙, where κ is the opacity in cm2 g‑1, and forming a magnetar with spin period P = 2 ms, and B = 2 × 1014 G (lower than other SLSNe with comparable rise times) can consistently explain the light curve evolution and high temperature at peak. The host metallicity, Z = 0.18 Z⊙, is comparable to other SLSNe.

  20. Study on the Superluminal Group Velocity in a Coaxial Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    LuGuizhen; HuangZhixun; GuanJian

    2004-01-01

    In this paper, the superluminal group velocity in a coaxial photonic crystal is studied. The simulation of the effective refraction index in coaxial photonic crystal is performed. The group velocity is calculated based on the transmission line equations and compared with experimental results.

  1. Superluminal neutrinos and extra dimensions: constraints from the null energy condition

    OpenAIRE

    Gubser, Steven S.

    2011-01-01

    In light of the recent results from the OPERA collaboration, indicating that neutrinos can travel superluminally, I review a simple extra-dimensional strategy for accommodating such behavior; and I also explain why it is hard in this strategy to avoid violating the null energy condition somewhere in the extra dimensions.

  2. Accretion disc geometry evolution of GRS 1915+105 during its plataeu states

    Science.gov (United States)

    Sarathi Pal, Partha; Gopal Dutta, Broja; Chakrabarti, Sandip Kumar

    2016-07-01

    The evolution of Time-lags are correlated with the accretion geometry during Plateau states of GRS 1915+105. We find that the lag spectrum for the χ_3 class is different from that of χ_1, χ_2 and χ_4 classes. Hard lags occur only when Comptonizing efficiency (CE) is about 0.9% for different plateau states and its evolution follows the sequence of class transitions suggested on the basis of CE parameter. We conclude that the variation of time lags could be due to change of size of the CENBOL which is often triggered by Compton cooling process.

  3. Evidence for a relativistic iron line in GRS 1915+105

    CERN Document Server

    Martocchia, A; Karas, V; Belloni, T; Feroci, M

    2002-01-01

    We report on the discovery of a relativistic iron K\\alpha fluorescent emission line in the BeppoSAX spectrum of the microquasar GRS 1915+105, taken on April 19, 1998, when the line was unusually intense. The feature is broad and skewed, clearly indicating emission from the innermost regions of the accretion disc. The inner emitting orbit is larger than the innermost stable orbit, even in Schwarzschild metric: thus, a non-zero BH spin is not required by these data.

  4. Exploring the Long-Term Evolution of GRS 1915+105

    CERN Document Server

    Huppenkothen, D; Hogg, D W; Müller, A

    2016-01-01

    Among the population of known galactic black hole X-ray binaries, GRS 1915+105 stands out in multiple ways. It has been in continuous outburst since 1992, and has shown a wide range of different states that can be distinguished by their timing and spectral properties. These states, also observed in IGR J17091-3624, have in the past been linked to accretion dynamics. Here, we present the first comprehensive study into the long-term evolution of GRS 1915+105, using the entire data set observed with RXTE over its sixteen-year lifetime. We develop a set of descriptive features allowing for automatic separation of states, and show that supervised machine learning in the form of logistic regression and random forests can be used to efficiently classify the entire data set. For the first time, we explore the duty cycle and time evolution of states over the entire sixteen-year time span, and find that the temporal distribution of states has significantly changed over the span of the observations. We connect the machi...

  5. Using machine learning to explore the long-term evolution of GRS 1915+105

    Science.gov (United States)

    Huppenkothen, Daniela; Heil, Lucy M.; Hogg, David W.; Mueller, Andreas

    2017-04-01

    Among the population of known Galactic black hole X-ray binaries, GRS 1915+105 stands out in multiple ways. It has been in continuous outburst since 1992, and has shown a wide range of different states that can be distinguished by their timing and spectral properties. These states, also observed in IGR J17091-3624, have in the past been linked to accretion dynamics. Here, we present the first comprehensive study into the long-term evolution of GRS 1915+105, using the entire data set observed with Rossi X-ray Timing Explorer over its 16-yr lifetime. We develop a set of descriptive features allowing for automatic separation of states, and show that supervised machine learning in the form of logistic regression and random forests can be used to efficiently classify the entire data set. For the first time, we explore the duty cycle and time evolution of states over the entire 16-yr time span, and find that the temporal distribution of states has likely changed over the span of the observations. We connect the machine classification with physical interpretations of the phenomenology in terms of chaotic and stochastic processes.

  6. NuSTAR Spectroscopy of GRS 1915+105: Disk Reflection, Spin, and Connections to Jets

    CERN Document Server

    Miller, J M; Fuerst, F; Bachetti, M; Harrison, F A; Barret, D; Boggs, S E; Chakrabarty, D; Christensen, F E; Craig, W W; Fabian, A C; Grefenstette, B W; Hailey, C J; King, A L; Stern, D K; Tomsick, J A; Walton, D J; Zhang, W W

    2013-01-01

    We report on the results of spectral fits made to a NuSTAR observation of the black hole GRS 1915+105 in a "plateau" state. This state is of special interest because it is similar to the "low/hard" state seen in other black holes, especially in that compact, steady jets are launched in this phase. The 3-79 keV bandpass of NuSTAR, and its ability to obtain moderate-resolution spectra free from distortions such as photon pile-up, are extremely well suited to studies of disk reflection in X-ray binaries. In only 15 ks of net exposure, an extraordinarily sensitive spectrum of GRS 1915+105 was measured across the full bandpass. Ionized reflection from a disk around a rapidly-spinning black hole is clearly required to fit the spectra; even hybrid Comptonization models including ionized reflection from a disk around a Schwarzschild black hole proved inadequate. A spin parameter of a = 0.98 +/- 0.01 (1-sigma statistical error) is measured via the best-fit model; low spins are ruled out at a high level of confidence. ...

  7. High-Frequency Quasi-Periodic Oscillations from GRS 1915+105

    CERN Document Server

    Belloni, Tomaso M

    2013-01-01

    We report the results of a systematic timing analysis of all archival Rossi X-Ray Timing Explorer (RXTE) observations of the bright black-hole binary GRS 1915+105 in order to detect high-frequency quasi-periodic oscillations (HFQPO). We produced power-density spectra in two energy bands and limited the analysis to the frequency range 30-1000 Hz. We found 51 peaks with a single trial significance larger than 3 sigma. As all but three have centroid frequencies that are distributed between 63 and 71 Hz, we consider most of them significant regardless of the number of trials involved. The average centroid frequency and FWHM are 67.3 +/- 2.0 Hz and 4.4 +/- 2.4 Hz respectively. Their fractional rms varies between 0.4% and 2% (total band detections) and between 0.5% and 3% (hard ban detections). As GRS 1915+105 shows large variability on time scales longer than 1s, we analysed the data in 16s intervals and found that the detections are limited to a specific region in the colour-colour diagram, corresponding to state...

  8. X-ray Spectral Analysis of the Steady States of GRS 1915+105

    CERN Document Server

    Peris, Charith S; Steiner, James F; Vrtilek, Saeqa D; Varniere, Peggy; Rodriguez, Jerome; Pooley, Guy

    2015-01-01

    We report on the X-ray spectral behavior within the steady states of GRS 1915+105. Our work is based on a vast data set obtained using the Proportional Counter Array on the Rossi X-ray Timing Explorer (RXTE/PCA) during the course of its entire mission (1996-2012). We also utilized 15 GHz radio data obtained using the Ryle Telescope from 1995 to 2006. The steady observations within the X-ray data set naturally separated into two regions in the color-color diagram and we refer to them as steady-soft and steady-hard. GRS 1915+105 displays significant curvature in the coronal component in both the soft and hard data within the RXTE/PCA bandpass. We fit both steady-soft and steady-hard observations with a model comprised of 'simplcut' in tandem with a multicolor disk model 'ezdiskbb' with the steady-soft observations requiring a slightly more complex overall model. A majority of the steady-soft observations displays a roughly constant inner disk radius, reminiscent of canonical soft state black hole binaries. On t...

  9. Compressive Creep Response of T1000G/RS-14 Graphite/Polycyanate Composite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Starbuck, J.M.

    1998-01-01

    The response of a T1000G/RS-14 graphite/polycyanate composite material system to transverse compressive loads is quantified via experimentation. The primary objective of the work was to quantify the effects of process environment and test environment on the T1000G/RS-14 compressive creep response. Tests were conducted on both the neat resin and the composite material system. In addition to the creep tests, static compressive strength tests were conducted to define the stress-strain response. The creep behavior for the RS-14 resin was quantified by conducting a series of tests to study the effects of different process environments (air and nitrogen), different cure temperatures, and different test environments (air and vacuum). The combined effect on the RS-14 resin compressive creep of processing in nitrogen and testing under vacuum versus processing in air and testing in air was a 47% decrease in the creep strain after 2177 hr. The test environment appeared to have a greater effect on the resin creep than the process environment. Following the conclusion of the resin creep tests, composite transverse compressive creep tests were conducted. The composite creep test cylinder was post-cured in a nitrogen environment prior to machining test specimens and all tests were conducted in a vacuum environment. The series of tests investigated the effects of initial stress level and test temperature on the creep behavior. At the end of the 2000-hr tests at 275{degrees}F on specimens stressed at 10,000 psi, the nitrogen-processed and vacuum-tested conditions reduced the composite transverse compressive creep strain by 19% compared to processing in air and testing in air. The effects of process and test environment on the creep behavior are not as great for the composite system as they were for the neat resin, primarily because of the low resin content in the composite material system. At the 275{degrees}F test temperature there was a significant increase in the composite

  10. Astrosat/LAXPC Reveals the High-energy Variability of GRS 1915+105 in the X Class

    Science.gov (United States)

    Yadav, J. S.; Misra, Ranjeev; Verdhan Chauhan, Jai; Agrawal, P. C.; Antia, H. M.; Pahari, Mayukh; Dedhia, Dhiraj; Katoch, Tilak; Madhwani, P.; Manchanda, R. K.; Paul, B.; Shah, Parag; Ishwara-Chandra, C. H.

    2016-12-01

    We present the first quick look analysis of data from nine AstroSat's Large Area X-ray Proportional Counter (LAXPC) observations of GRS 1915+105 during 2016 March when the source had the characteristics of being in the Radio-quiet χ class. We find that a simple empirical model of a disk blackbody emission, with Comptonization and a broad Gaussian Iron line can fit the time-averaged 3-80 keV spectrum with a systematic uncertainty of 1.5% and a background flux uncertainty of 4%. A simple dead time corrected Poisson noise level spectrum matches well with the observed high-frequency power spectra till 50 kHz and as expected the data show no significant high-frequency (\\gt 20 {Hz}) features. Energy dependent power spectra reveal a strong low-frequency (2-8 Hz) quasi-periodic oscillation and its harmonic along with broadband noise. The QPO frequency changes rapidly with flux (nearly 4 Hz in ˜5 hr). With increasing QPO frequency, an excess noise component appears significantly in the high-energy regime (\\gt 8 keV). At the QPO frequencies, the time-lag as a function of energy has a non-monotonic behavior such that the lags decrease with energy till about 15-20 keV and then increase for higher energies. These first-look results benchmark the performance of LAXPC at high energies and confirms that its data can be used for more sophisticated analysis such as flux or frequency-resolved spectro-timing studies.

  11. Simulation approaches for the two-phase flow in saline repositories using the code TOUGH2-GRS. Report in the frame of the project ZIESEL. Two-phase flow in a saline repository using the example ERAM; Ansaetze zur Simulation der Zweiphasenstroemung in salinaren Endlagern mit dem Code TOUGH2-GRS. Bericht im Vorhaben ZIESEL. Zweiphasenfluss in einem salinaren Endlager am Beispiel des ERAM

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Martin; Fischer, Heidemarie; Seher, Holger; Weyand, Torben

    2016-10-15

    The simulation approaches for the two-phase flow in saline repositories using the code TOUGH2-GRS cover the following issues: simulation of gravitational flows in horizontal galleries without vertical discretization, homogenization approach for the simulation of the two-phase flow in converging partly backfilled galleries, qualification of the convergence approach implemented by GRS into the code TOUGH2-GRS, discretization effects during replacement of liquid by gas, consequences for the system analyses in the frame of the project ZIESEL.

  12. A Non-Mainstream Viewpoint on Apparent Superluminal Phenomena in AGN Jet

    Indian Academy of Sciences (India)

    Wen-Po Liu; Li-Yan Liu; Chun-Cheng Wang

    2014-09-01

    The group velocity of light in material around the AGN jet is acquiescently one ( as a unit), but this is only a hypothesis. Here, we re-derive apparent superluminal and Doppler formulas for the general case (it is assumed that the group velocity of light in the uniform and isotropic medium around a jet (a beaming model) is not necessarily equal to one, e.g., Araudo et al. (2010) thought that there may be dense clouds around AGN jet base), and show that the group velocity of light close to one could seriously affect apparent superluminal phenomena and Doppler effect in the AGN jet (when the viewing angle and Lorentz factor take some appropriate values).

  13. Diffusion Simulation of Outer Radiation Belt Electron Dynamics Induced by Superluminous L-O Mode Waves

    Institute of Scientific and Technical Information of China (English)

    XIAO Fu-Liang; HE Zhao-Guo; ZHANG Sai; SU Zhen-Peng; CHEN Liang-Xu

    2011-01-01

    Temporal evolution of outer radiation belt electron dynamics resulting from superluminous L-O mode waves is simulated at L=6.5. Diffusion rates are evaluated and then used as inputs to solve a 2D momentum-pitch-angle diffusion equation, particularly with and without cross diffusion terms. Simulated results demonstrate that phase space density(PSD) of energetic electrons due to L-O mode waves can enhance significantly within 24 h, covering a broader pitch-angle range in the absence of cross terms than that in the presence of cross terms. PSD evolution is also determined by the peak wave frequency, particularly at high kinetic energies. This result indicates that superluminous waves can be a potential candidate responsible for outer radiation belt electron dynamics.

  14. Dynamic evolution of outer radiation belt electrons driven by superluminous R-X mode waves

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We present initial results on the temporal evolution of the phase space density (PSD) of the outer radiation belt energetic electrons driven by the superluminous R-X mode waves. We calculate diffusion rates in pitch angle and momentum assuming the standard Gaussian distributions in both wave frequency and wave normal angle at the location L=6.5. We solve a 2D momentum-pitch-angle Fokker-Planck equation using those diffusion rates as inputs. Numerical results show that R-X mode can produce significant acceleration of relativistic electrons around geostationary orbit,supporting previous findings that superluminous waves potentially contribute to dramatic variation in the outer radiation belt electron dynamics.

  15. Emission of correlated photon pairs from superluminal perturbations in dispersive media

    CERN Document Server

    Piazza, Francesco Dalla; Cacciatori, Sergio Luigi; Faccio, Daniel

    2012-01-01

    We develop a perturbative theory that describes a superluminal refractive perturbation propagating in a dispersive medium and the subsequent excitation of the quantum vacuum zero-point fluctuations. We find a process similar to the anomalous Doppler effect: photons are emitted in correlated pairs and mainly within a Cerenkov-like cone, one on the forward and the other in backward directions. The number of photon pairs emitted from the perturbation increases strongly with the degree of superluminality and under realizable experimental conditions, it can reach up to ~0.01 photons per pulse. Moreover, it is in principle possible to engineer the host medium so as to modify the effective group refractive index. In the presence of "fast light" media, e.g. a with group index smaller than unity, a further ~10x enhancement may be achieved and the photon emission spectrum is characterized by two sharp peaks that, in future experiments would clearly identify the correlated emission of photon pairs.

  16. Gain-assisted superluminal light propagation through a Bose-Einstein condensate cavity system

    Science.gov (United States)

    Hamide Kazemi, S.; Ghanbari, S.; Mahmoudi, M.

    2016-01-01

    The propagation of a probe laser field in a cavity optomechanical system with a Bose-Einstein condensate is studied. The transmission properties of the system are investigated and it is shown that the group velocity of the probe pulse field can be controlled by Rabi frequency of the pump laser field. The effect of the decay rate of the cavity photons on the group velocity is studied and it is demonstrated that for small values of the decay rates, the light propagation switches from subluminal to superluminal just by changing the Rabi frequency of the pump field. Then, the gain-assisted superluminal light propagation due to the cross-Kerr nonlinearity is established in cavity optomechanical system with a Bose-Einstein condensate. Such behavior can not appear in the pump-probe two-level atomic systems in the normal phase. We also find that the amplification is achieved without inversion in the population of the quantum energy levels.

  17. Causal ubiquity in quantum physics. A superluminal and local-causal physical ontology

    Energy Technology Data Exchange (ETDEWEB)

    Neelamkavil, Raphael

    2014-07-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly [non-causal] processes, something exists processually in extension-motion, between the causal and the [non-causal]. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That is, the QM world is sub-luminally, luminally and superluminally local-causal throughout, and the Law of Causality is ubiquitous in the micro-world. Thus, ''probabilistic causality'' is a merely epistemic term.

  18. Sub- and super-luminal light propagation using a Rydberg state

    CERN Document Server

    Bharti, Vineet

    2016-01-01

    We present a theoretical study to investigate sub- and super-luminal light propagation in a rubidium atomic system consisting of a Rydberg state by using density matrix formalism. The analysis is performed in a 4-level vee+ladder system interacting with a weak probe, and strong control and switching fields. The dispersion and absorption profiles are shown for stationary atoms as well as for moving atoms by carrying out Doppler averaging at room temperature. We also present the group index variation with control Rabi frequency and observe that a transparent medium can be switched from sub- to super-luminal propagation in the presence of switching field. Finally, the transient response of the medium is discussed, which shows that the considered 4-level scheme has potential applications in absorptive optical switching.

  19. Self-accelerating Massive Gravity: Superluminality, Cauchy Surfaces and Strong Coupling

    CERN Document Server

    Motloch, Pavel; Joyce, Austin; Motohashi, Hayato

    2015-01-01

    Self-accelerating solutions in massive gravity provide explicit, calculable examples that exhibit the general interplay between superluminality, the well-posedness of the Cauchy problem, and strong coupling. For three particular classes of vacuum solutions, one of which is new to this work, we construct the conformal diagram for the characteristic surfaces on which isotropic stress-energy perturbations propagate. With one exception, all solutions necessarily possess spacelike characteristics, indicating perturbative superluminality. Foliating the spacetime with these surfaces gives a pathological frame where kinetic terms of the perturbations vanish, confusing the Hamiltonian counting of degrees of freedom. This frame dependence distinguishes the vanishing of kinetic terms from strong coupling of perturbations or an ill-posed Cauchy problem. We give examples where spacelike characteristics do and do not originate from a point where perturbation theory breaks down and where spacelike surfaces do or do not inte...

  20. GRS' research on clay rock in the Mont Terri underground laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Wieczorek, Klaus; Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit gGmbH, Braunschweig (Germany)

    2016-07-15

    For constructing a nuclear waste repository and for ensuring the safety requirements are met over very long time periods, thorough knowledge about the safety-relevant processes occurring in the coupled system of waste containers, engineered barriers, and the host rock is indispensable. For respectively targeted research work, the Mont Terri rock laboratory is a unique facility where repository research is performed in a clay rock environment. It is run by 16 international partners, and a great variety of questions are investigated. Some of the work which GRS as one of the Mont Terri partners is involved in is presented in this article. The focus is on thermal, hydraulic and mechanical behaviour of host rock and/or engineered barriers.

  1. Comptonization efficiencies of the variability classes of GRS 1915+105

    CERN Document Server

    Pal, Partha Sarathi; Nandi, Anuj

    2013-01-01

    The Galactic microquasar GRS 1915+105 exhibits at least seventeen types of variability classes. Intra and inter class transitions are reported to be observed within seconds to hours. Since the observation was not continuous, these classes appeared to be exhibited in a random order. Our goal is to predict a sequence of these classes. In this paper, we compute the ratio of the photon counts obtained from the power-law component and the blackbody component of each class and call this ratio as the `Comptonizing efficiency' (CE) of that class. We sequence the classes in the ascending order of CE and find that this sequence matches with a few class transitions observed by RXTE satellite and IXAE instruments on board IRS-P3. A change in CE corresponds to a change in the optical depth of the Compton cloud. Our result implies that the optical depth of the Compton cloud gradually rises as the variability class becomes harder.

  2. GRS Method for Uncertainties Evaluation of Parameters in a Prospective Fast Reactor

    Science.gov (United States)

    Peregudov, A.; Andrianova, O.; Raskach, K.; Tsibulya, A.

    2014-04-01

    A number of recent studies have been devoted to the uncertainty estimation of reactor calculation parameters by the GRS (Generation Random Sampled) method. This method is based on direct sampling input data resulting in formation of random sets of input parameters which are used for multiple calculations. Once these calculations are performed, statistical processing of the calculation results is carried out to determine the mean value and the variance of each calculation parameter of interest. In our study this method is used to estimate the uncertainty of calculation parameters (keff, power density, dose rate) of a prospective sodium-cooled fast reactor. Neutron transport calculations were performed by the nodal diffusion code TRIGEX and Monte Carlo code MMK.

  3. Revisiting Evidence of Chaos in X-ray Light Curves: The Case of GRS 1915+105

    CERN Document Server

    Mannattil, Manu; Chakraborty, Sagar

    2016-01-01

    Nonlinear time series analysis has been widely used to search for signatures of low-dimensional chaos in light curves emanating from astrophysical bodies. A particularly popular example is the microquasar GRS 1915+105, whose irregular but systematic X-ray variability has been well studied using data acquired by the Rossi X-ray Timing Explorer (RXTE). With a view to building simpler models of X-ray variability, attempts have been made to classify the light curves of GRS 1915+105 as chaotic or stochastic. Contrary to some of the earlier suggestions, after careful analysis, we find no evidence for chaos or determinism in any of the GRS 1915+105 classes. The dearth of long and stationary data sets representing all the different variability classes of GRS 1915+105 make it a poor candidate for analysis using nonlinear time series techniques. We conclude that either very exhaustive data analysis with sufficiently long and stationary light curves should be performed keeping all the pitfalls of nonlinear time series a...

  4. On determination of the geometric cosmological constant from the OPERA experiment of superluminal neutrinos

    OpenAIRE

    Yan, Mu-Lin; Hu, Sen; Huang, Wei; Xiao, Neng-Chao

    2011-01-01

    The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant $\\Lambda_{eff}$ which is the sum of the quantum zero point energy $\\Lambda_{dark energy}$ and the geometric cosmological constant $\\Lambda$. The OPERA experiment can be applied to determine the geometric cosmological constant $\\Lambda$. It is the first time to distingui...

  5. Swift and LT UV and optical observations of type IIn superluminous supernova 2017gir

    Science.gov (United States)

    Cano, Zach; Kuin, Paul; Chandra, Poonam; Ashall, Chris; Malesani, Daniele; Pastorello, Andrea

    2017-09-01

    We observed the field of the type IIn superluminous supernova 2017gir (ATLAS17jsb, Tonry et al. 2017; Lyman et al. 2017, ATel 10674) with Swift via a target-of-opportunity for three epochs (6th, 16th and 19th of September, 2017) in the three UVOT UV filters (w1, m1, w2). The SN is clearly detected in all three filters, and it is seen that its brightness fades over this timescale.

  6. Superluminal Neutrinos from Special Relativity with de Sitter Space-time Symmetry

    OpenAIRE

    Yan, Mu-Lin; Xiao, Neng-Chao; Huang, Wei; Hu, Sen

    2011-01-01

    We explore the recent OPERA experiment of superluminal neutrinos in the framework of Special Relativity with de Sitter space-time symmetry (dS-SR). According to Einstein a photon is treated as a massless particle in the framework of Special Relativity. In Special Relativity (SR) we have the universal parameter $c$, the photon velocity $c_{photon}$ and the phase velocity of a light wave in vacuum $c_{wave}=\\lambda\

  7. Considerations about the apparent ''superluminal expansions'' observed in astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Recami, E.; Castellino, A.; Maccarrone, G.D.; Rodono, M.

    1986-06-11

    The orthodox models devised to explain the apparent ''superluminal expansions'' observed in astrophysics - and here briefly summarized and discussed together with the experimental data - do not seem to be too much successful, especially when confronted with the most recent observations, suggesting complicated expansion patterns, even with possible accelerations. At this point it may be, therefore, of some interest to explore the possible alternative models in which actual Superluminal motions take place. To prepare the ground, we start from a variational principle, introduce the elements of a tachyon mechanics within special relativity, and argue about the expected behaviour of tachyonic objects when interacting (gravitationally, for instance) among themselves or with ordinary matter. We then review and develop the simplet ''Superluminal models'', paying particular attention to the observations which they would give rise to. We conclude that some of them appear to be physically acceptable and are statistically favoured with respect to the orthodox ones.

  8. Ionization Break-Out from Millisecond Pulsar Wind Nebulae: an X-ray Probe of the Origin of Superluminous Supernovae

    CERN Document Server

    Metzger, Brian D; Hascoet, Romain; Beloborodov, Andrei M

    2013-01-01

    Magnetic spin-down of a millisecond neutron star has been proposed as the power source of hydrogen-poor "superluminous" supernovae (SLSNe-I). However, producing an unambiguous test that can distinguish this model from alternatives, such as circumstellar interaction, has proven challenging. After the supernova explosion, the pulsar wind inflates a hot cavity behind the expanding stellar ejecta: the nascent millisecond pulsar wind nebula. Electron/positron pairs injected by the wind cool through inverse Compton scattering and synchrotron emission, producing a pair cascade and hard X-ray spectrum inside the nebula. These X-rays ionize the inner exposed side of the ejecta, driving an ionization front that propagates outwards with time. Under some conditions this front can breach the ejecta surface within months after the optical supernova peak, allowing ~0.1-1 keV photons to escape the nebula unattenuated with a characteristic luminosity L_X ~ 1e43-1e45 erg/s. This "ionization break-out" may explain the luminous ...

  9. Aspects of Quantum Non-Locality I: Superluminal Signalling, Action-at-a-Distance, Non-Separability and Holism

    Science.gov (United States)

    Berkovitz, Joseph

    In this paper and its sequel, I consider the significance of Jarrett's and Shimony's analyses of the so-called factorisability (Bell-locality) condition for clarifying the nature of quantum non-locality. In this paper, I focus on four types of non-locality: superluminal signalling, action-at-a-distance, non-separability and holism. In the second paper, I consider a fifth type of non-locality: superluminal causation according to 'logically weak' concepts of causation, where causal dependence requires neither action nor signalling. In this connection, I pay special attention to the difficulties that superluminal causation raises in relativistic space-time. I conclude by evaluating the relevance of Jarrett's and Shimony's analyses for clarifying the question of the compatibility of quantum non-locality with relativity theory. My main conclusions are, first: these analyses are significant for clarifying the questions of superluminal signalling in quantum phenomena and for the compatibility of these phenomena with relativity. But, second, by contrast: these analyses are not very significant for the study of action-at-a distance, superluminal causation, non-separability and holism in quantum phenomena.

  10. A proposal for a feasible quantum-optical scheme to test for the existence of superluminal signals via quantum mechanical entanglement

    CERN Document Server

    Kalamidas, Demetrios A

    2011-01-01

    Motivated by a proposal from Greenberger [Physica Scripta T76, p.57 (1998) ] for superluminal signaling, and inspired by an experiment from Mandel [Phys. Rev. Lett. 67, p.318 (1991) ] showing interference effects within multi-particle entanglement without coincidence detection, we propose a feasible quantum-optical scheme that purports to manifest the capacity for superluminal transfer of information between distant parties.

  11. Immobilization of alpha-amylase produced by Bacillus circulans GRS 313

    Directory of Open Access Journals (Sweden)

    Gargi Dey

    2003-03-01

    Full Text Available A maltooligosaccharide-forming amylase from B circulans GRS 313 was immobilized by entrapment in calcium alginate beads. The immobilized activity was affected by the size of the bead and bead size of 2mm was found to be most effective for hydrolysis. Kinetics constants, Km and Vmax were estimated and were found to be affected by the bead size. The catalytic activity of the enzyme was studied in presence of various starchy residues and metal ions. HgCl2, CuSO4 and FeCl3 caused inhibition of the enzyme. The reaction conditions, pH and temperature, was optimized using response surface methodology. At the optimum pH and temperature of 4.9 and 57ºC, the apparent activity was 25.6U/g of beads, resulting in almost 2-fold increase in activity. The immobilized enzyme showed a high operational stability by retaining almost 85% of the initial activity after seventh use.Um maltooligossacarideo obtido a partir de amilase produzida por B. circulans GRS 313 foi imobilizada em alginato de sódio. A atividade enzimática foi afetada pelo tamanho da partícula. Partículas com 2mm foram as mais efetivas na hidrólise. Constantes cinética Km e Vmax foram estimadas e afetadas pelo tamanho das partículas. A atividade catalítica da enzima foi estuda na presença de diferentes tipos de amido e íons metálicos. HgCl2, CuSO4 e FeCl3 provocaram inibição na enzima. As condições de reação (temperatura e pH foram otimizadas utilizando a metodologia da superfície de resposta. Em pH ótimo de 4,9 e temperatura de 57 ºC, a atividade aparente foi de 25.6 U/g de partículas, resultando num acréscimo de mais de 2 vezes na atividade da enzima. A imobilização da enzima mostrou uma alta estabilidade operacional pela retenção de 85% de sua atividade inicial após sete ciclos de utilização.

  12. A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS

    CERN Document Server

    Antonello, M.; Baibussinov, B.; Baldo Ceolin, M.; Benetti, P.; Calligarich, E.; Canci, N.; Carbonara, F.; Centro, S.; Cesana, A.; Cieslik, K.; Cline, D.B.; Cocco, A.G.; Dabrowska, A.; Dequal, D.; Dermenev, A.; Dolfini, R.; Farnese, C.; Fava, A.; Ferrari, A.; Fiorillo, G.; Gibin, D.; Gigli Berzolari, A.; Gninenko, S.; Guglielmi, A.; Haranczyk, M.; Holeczek, J.; Ivashkin, A.; Kisiel, J.; Kochanek, I.; Lagoda, J.; Mania, S.; Mannocchi, G.; Menegolli, A.; Meng, G.; Montanari, C.; Otwinowski, S.; Periale, L.; Piazzoli, A.; Picchi, P.; Pietropaolo, F.; Plonski, P.; Rappoldi, A.; Raselli, G.L.; Rossella, M.; Rubbia, C.; Sala, P.R.; Scantamburlo, E.; Scaramelli, A.; Segreto, E.; Sergiampietri, F.; Stefan, D.; Stepaniak, J.; Sulej, R.; Szarska, M.; Terrani, M.; Varanini, F.; Ventura, S.; Vignoli, C.; Wang, H.; Yang, X.; Zalewska, A.; Zaremba, K.; Cohen, A.

    2012-01-01

    The OPERA collaboration [1] has claimed evidence of superluminal propagation between CERN and the LNGS with . We find that the neutrino energy distribution of the ICARUS events in LAr agrees with the expectations from the Monte Carlo predictions from an unaffected energy distribution of beam from CERN. Our results therefore refute a superluminal interpretation of the OPERA result according to the Cohen and Glashow prediction [2] for a weak currents analog to Cherenkov radiation. In particular no events with a superluminal Cherenkov like e+e- pair or gamma emission have been directly observed inside the fiducial volume of the "bubble chamber like" ICARUS TPC-LAr detector, setting much stricter limits to the value of delta comparable with the one due to the observations from the SN1987A.

  13. Discovery of a 34 Hz Quasi-Periodic Oscillation in the X-ray emission of GRS 1915+105

    CERN Document Server

    Belloni, Tomaso M; -,

    2013-01-01

    We report the discovery in the Rossi X-Ray Timing Explorer data of GRS 1915+105 of a second quasi-periodic oscillation at 34 Hz, simultaneous with that observed at 68 Hz in the same observation. The data corresponded to those observations from 2003 where the 68-Hz oscillation was very strong. The significance of the detection is 4.2 sigma. These observations correspond to a very specific position in the colour-colour diagram for GRS 1915+105, corresponding to a harder spectrum compared to those where a 41 Hz oscillation was discovered. We discuss the possible implications of the new pair of frequencies comparing them with the existing theoretical models.

  14. The Accretion Disk Wind in the Black Hole GRS 1915+105

    CERN Document Server

    Miller, J M; Fabian, A C; Gallo, E; Kaastra, J; Kallman, T; King, A L; Proga, D; Reynolds, C S; Zoghbi, A

    2016-01-01

    We report on a 120 ks Chandra/HETG spectrum of the black hole GRS 1915+105. The observation was made during an extended and bright soft state in June, 2015. An extremely rich disk wind absorption spectrum is detected, similar to that observed at lower sensitivity in 2007. The very high resolution of the third-order spectrum reveals four components to the disk wind in the Fe K band alone; the fastest has a blue-shift of v = 0.03c. Broadened re-emission from the wind is also detected in the first-order spectrum, giving rise to clear accretion disk P Cygni profiles. Dynamical modeling of the re-emission spectrum gives wind launching radii of r ~ 10^(2-4) GM/c^2. Wind density values of n ~ 10^(13-16) cm^-3 are then required by the ionization parameter formalism. The small launching radii, high density values, and inferred high mass outflow rates signal a role for magnetic driving. With simple, reasonable assumptions, the wind properties constrain the magnitude of the emergent magnetic field to B ~ 10^(3-4) Gauss ...

  15. Calibrated Estimates of the Energy in Major Flares of GRS 1915+105

    CERN Document Server

    Punsly, Brian

    2013-01-01

    We analyze the energetics of the major radio flare of October 8 2005 in GRS 1915+105. The flare is of particular interest because it is one of the most luminous and energetic radio flares from a Galactic black hole that has ever been observed. The motivation is two-fold. One, to learn more about the energetics of this most extreme phenomenon and its relationship to the accretion state. The second is to verify if the calibrated estimates of the energy of major radio flares (based on the peak low frequency optically thin flux) derived from flares in the period 1996-2001 in Punsly & Rodriguez (2013), PR13 hereafter, can be used to estimate plasmoid energy beyond this time period. We find evidence that the calibrated curves are still accurate for this strong flare. Furthermore, the physically important findings of PR13 are supported by the inclusion of this flare: the flare energy is correlated with both the intrinsic bolometric X-ray luminosity, $L_{\\mathrm{bol}}$, $\\sim 1$ hour before ejection and $L_{\\math...

  16. The Accretion Flow - Discrete Ejection Connection in GRS 1915+105

    CERN Document Server

    Punsly, Brian; Trushkin, Sergei A

    2016-01-01

    The microquasar GRS~1915+105 is known for its spectacular discrete ejections. They occur unexpectedly, thus their inception escapes direct observation. It has been shown that the X-ray flux increases in the hours leading up to a major ejection. In this article, we consider the serendipitous interferometric monitoring of a modest version of a discrete ejection described in Reid et al. (2014) that would have otherwise escaped detection in daily radio light curves. The observation begins $\\sim 1$ hour after the onset of the ejection, providing unprecedented accuracy on the estimate of the ejection time. The astrometric measurements allow us to determine the time of ejection as $\\rm{MJD}\\, 56436.274^{+0.016}_{-0.013}$, i.e., within a precision of 41 minutes (95\\% confidence). Just like larger flares, we find that the X-ray luminosity increases in last 2 - 4 hours preceding ejection. Our finite temporal resolution indicates that this elevated X-ray flux persists within $21.8^{+22.6}_{-19.1}$ minutes of the ejectio...

  17. Accretion disk winds as the jet suppression mechanism in the microquasar GRS 1915+105.

    Science.gov (United States)

    Neilsen, Joseph; Lee, Julia C

    2009-03-26

    Stellar-mass black holes with relativistic jets, also known as microquasars, mimic the behaviour of quasars and active galactic nuclei. Because timescales around stellar-mass black holes are orders of magnitude smaller than those around more distant supermassive black holes, microquasars are ideal nearby 'laboratories' for studying the evolution of accretion disks and jet formation in black-hole systems. Whereas studies of black holes have revealed a complex array of accretion activity, the mechanisms that trigger and suppress jet formation remain a mystery. Here we report the presence of a broad emission line in the faint, hard states and narrow absorption lines in the bright, soft states of the microquasar GRS 1915+105. ('Hard' and 'soft' denote the character of the emitted X-rays.) Because the hard states exhibit prominent radio jets, we argue that the broad emission line arises when the jet illuminates the inner accretion disk. The jet is weak or absent during the soft states, and we show that the absorption lines originate when the powerful radiation field around the black hole drives a hot wind off the accretion disk. Our analysis shows that this wind carries enough mass away from the disk to halt the flow of matter into the radio jet.

  18. The Galactic center X-ray transients AX J1745.6-2901 and GRS 1741-2853

    CERN Document Server

    Degenaar, N; Reynolds, M T; Miller, J M; Kennea, J; Gehrels, N

    2014-01-01

    AX J1745.6-2901 and GRS 1741-2853 are two transient neutron star low-mass X-ray binaries that are located within ~10' from the Galactic center. Multi-year monitoring observations with the Swift/XRT has exposed several accretion outbursts from these objects. We report on their updated X-ray light curves and renewed activity that occurred in 2010-2013.

  19. An integral monitoring of GRS1915+105: simultaneous observations with INTEGRAL, RXTE, the Ryle and Nancay radio telescopes

    CERN Document Server

    Rodríguez, J; Hannikainen, D C; Lehto, H J

    2006-01-01

    Since the launch of INTEGRAL in late 2002 we have monitored the Galactic microquasar GRS 1915+105 with long exposures (~100 ks) pointings. All the observations have been conducted simultaneously with other instruments, in particular RXTE and the Ryle Telescope, and in some cases with others (Spitzer, Nancay, GMRT, Suzaku,...). We report here the results of 3 observations performed simultaneously with INTEGRAL, RXTE, the Ryle and Nancay radio telescopes. These observations show the so-called $\

  20. Environmental measurement-while-drilling-gamma ray spectrometer (EMWD-GRS) system technology demonstration plan for use at the Savannah River Site F-Area Retention Basin

    Energy Technology Data Exchange (ETDEWEB)

    Williams, C.V.; Lockwood, G.J.; Normann, R.A. [Sandia National Labs., Albuquerque, NM (United States); Gruebel, R.D. [Tech Reps, Inc., Albuquerque, NM (United States)

    1996-08-01

    The Environmental Measurement-While-Drilling-Gamma Ray Spectrometer (EMWD-GRS) system represents an innovative blend of new and existing technology that provides the capability of producing real-time environmental and drillbit data during drilling operations. This demonstration plan presents information on the EMWD-GRS technology, demonstration design, Cs-137 contamination at the Savannah River Site F-Area Retention Basin, responsibilities of demonstration participants, and the policies and procedures for the demonstration to be conducted at the Savannah River Site F-Area Retention Basin. The EMWD-GRS technology demonstration will consist of continuously monitoring for gamma-radiation contamination while drilling two horizontal boreholes below the backfilled retention basin. These boreholes will pass near previously sampled vertical borehole locations where concentrations of contaminant levels are known. Contaminant levels continuously recorded by the EMWD-GRS system during drilling will be compared to contaminant levels previously determined through quantitative laboratory analysis of soil samples.

  1. Slowly fading super-luminous supernovae that are not pair-instability explosions

    Science.gov (United States)

    Nicholl, M.; Smartt, S. J.; Jerkstrand, A.; Inserra, C.; McCrum, M.; Kotak, R.; Fraser, M.; Wright, D.; Chen, T.-W.; Smith, K.; Young, D. R.; Sim, S. A.; Valenti, S.; Howell, D. A.; Bresolin, F.; Kudritzki, R. P.; Tonry, J. L.; Huber, M. E.; Rest, A.; Pastorello, A.; Tomasella, L.; Cappellaro, E.; Benetti, S.; Mattila, S.; Kankare, E.; Kangas, T.; Leloudas, G.; Sollerman, J.; Taddia, F.; Berger, E.; Chornock, R.; Narayan, G.; Stubbs, C. W.; Foley, R. J.; Lunnan, R.; Soderberg, A.; Sanders, N.; Milisavljevic, D.; Margutti, R.; Kirshner, R. P.; Elias-Rosa, N.; Morales-Garoffolo, A.; Taubenberger, S.; Botticella, M. T.; Gezari, S.; Urata, Y.; Rodney, S.; Riess, A. G.; Scolnic, D.; Wood-Vasey, W. M.; Burgett, W. S.; Chambers, K.; Flewelling, H. A.; Magnier, E. A.; Kaiser, N.; Metcalfe, N.; Morgan, J.; Price, P. A.; Sweeney, W.; Waters, C.

    2013-10-01

    Super-luminous supernovae that radiate more than 1044 ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of `pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of 56Ni are synthesized; this isotope decays to 56Fe via 56Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10-6 times that of the core-collapse rate.

  2. Slowly fading super-luminous supernovae that are not pair-instability explosions.

    Science.gov (United States)

    Nicholl, M; Smartt, S J; Jerkstrand, A; Inserra, C; McCrum, M; Kotak, R; Fraser, M; Wright, D; Chen, T-W; Smith, K; Young, D R; Sim, S A; Valenti, S; Howell, D A; Bresolin, F; Kudritzki, R P; Tonry, J L; Huber, M E; Rest, A; Pastorello, A; Tomasella, L; Cappellaro, E; Benetti, S; Mattila, S; Kankare, E; Kangas, T; Leloudas, G; Sollerman, J; Taddia, F; Berger, E; Chornock, R; Narayan, G; Stubbs, C W; Foley, R J; Lunnan, R; Soderberg, A; Sanders, N; Milisavljevic, D; Margutti, R; Kirshner, R P; Elias-Rosa, N; Morales-Garoffolo, A; Taubenberger, S; Botticella, M T; Gezari, S; Urata, Y; Rodney, S; Riess, A G; Scolnic, D; Wood-Vasey, W M; Burgett, W S; Chambers, K; Flewelling, H A; Magnier, E A; Kaiser, N; Metcalfe, N; Morgan, J; Price, P A; Sweeney, W; Waters, C

    2013-10-17

    Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate.

  3. 超光速佯谬和中微子%Superluminal Paradox and Neutrino

    Institute of Scientific and Technical Information of China (English)

    倪光炯

    2002-01-01

    爱因斯坦的狭义相对论和因果原理意味着任何运动物体的速度不能超过光在真空中的速度.然而,有许多讨论超光速运动粒子的尝试,这些讨论或者是在狭义相对论的框架下进行的,或者是超越了狭义相对论.这些讨论都遇到一系列难以克服的困难,即"超光速佯谬".文中详细分析了这种佯谬,并证明它在与狭义相对论兼容的量子理论中显然是不出现的.在实在世界中,中微子最可能是一种超光速粒子.%Einstein′s theory of special relativity (SR) and the principle of causality imply that the speed of any moving object can not exceed that of light in a vacuum (c). However, there were many attempts in literature discussing the particle moving with speed u>c(called as superluminal particle or tachyon) either in the scheme of SR or beyond it. These theories all encountered a series of insurmountable difficulties which will be named "superluminal paradox"in this paper. We will analyze it in some detail and then prove that the paradox disappears unambiguously in quantum theory, which is compatible with SR. Most likely, the superluminal particle in real world is just a kind of known particle, the neutrino.

  4. Enhanced Sensitivity in a Superluminal Single Mode DPAL Cavity at Room Temperature

    Science.gov (United States)

    Abi-Salloum, Tony; Yablon, Joshua; Tseng, Shih; Shahriar, Selim

    2012-06-01

    The note beat between two counter-propagating beams in a cavity is used to measure the effective change of the length of the cavity or interferometer for applications such as optical gyroscopes, vibrometers, and gravitational wave detectors. We show in this talk how a superluminal single mode laser cavity can enhance the measured note beat dramatically. We consider the inhomogeneous broadening case and study the dependence of the enhancement factor on few key parameters. We also show how Diode Pump Alkali Lasers (DPAL) are excellent candidates for such devices. Using a Rubidium based DPAL, we study the characteristics of these lasers and their effect on the proposed enhanced sensitivity.

  5. Closed timelike curves, superluminal signals, and "free will" in universal quantum mechanics

    CERN Document Server

    Nikolic, H

    2010-01-01

    We explore some implications of the hypothesis that quantum mechanics (QM) is universal, i.e., that QM does not merely describe information accessible to observers, but that it also describes the observers themselves. From that point of view, "free will" (FW) - the ability of experimentalists to make free choices of initial conditions - is merely an illusion. As a consequence, by entangling a part of brain (responsible for the illusion of FW) with a distant particle, one may create nonlocal correlations that can be interpreted as superluminal signals. In addition, if FW is an illusion, then QM on a closed timelike curve can be made consistent even without the Deutch nonlinear consistency constraint.

  6. Superluminal Energy Transmission in the Goos-Hanchen Shift of Total Reflection

    CERN Document Server

    Wang, Z Y

    2011-01-01

    This paper is to give a counter example for the theory of relativity. Firstly, the dispersion relation of surface electromagnetic waves is corresponding to that of a tachyon where the coefficient of proportionality is the squared Planck constant. Then we prove the energy flow velocity S/w of the Goos-Hanchen shift in vacuum is cn.sinI>c as well according to electrodynamics. These two different ways lead to a same conclusion that energy transport in the Goos-Hanchen effect of total reflection is faster than light. It is also helpful to study the tachyon of particle physics and superluminal motion observed in astronomy,etc.

  7. On determination of the geometric cosmological constant from the OPERA experiment of superluminal neutrinos

    CERN Document Server

    Yan, Mu-Lin; Huang, Wei; Xiao, Neng-Chao

    2011-01-01

    The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant $\\Lambda_{eff}$ which is the sum of the quantum zero point energy $\\Lambda_{dark energy}$ and the geometric cosmological constant $\\Lambda$. The OPERA experiment can be applied to determine the geometric cosmological constant $\\Lambda$. It is the first time to distinguish the contributions of $\\Lambda$ and $\\Lambda_{dark energy}$ from each other by experiment. The determination is based on an explanation of the OPERA experiment in the framework of Special Relativity with de Sitter space-time symmetry.

  8. Superluminal Neutrinos from Special Relativity with de Sitter Space-time Symmetry

    CERN Document Server

    Yan, Mu-Lin; Huang, Wei

    2011-01-01

    We explore the recent OPERA experiment of superluminal neutrinos in the framework of Special Relativity with de Sitter space-time symmetry (dS-SR). According to Einstein, the photon is treated as the massless particle in the SR mechanics. The meanings of the universal parameter $c$ and the photon velocity $c_{photon}$ in SR have been analyzed. $c$ can be determined by means of the velocity-composition law in SR kinematically. And $c_{photon}$ is determined by the dispersion relations of SR. It is revealed that $c=c_{photon}$ in Einstein's Special Relativity (E-SR), but $c\

  9. Slow to superluminal light waves in thin 3D photonic crystals.

    Science.gov (United States)

    Galisteo-López, J F; Galli, M; Balestreri, A; Patrini, M; Andreani, L C; López, C

    2007-11-12

    Phase measurements on self-assembled three-dimensional photonic crystals show that the group velocity of light can flip from small positive (slow) to negative (superluminal) values in samples of a few mum size. This phenomenon takes place in a narrow spectral range around the second-order stop band and follows from coupling to weakly dispersive photonic bands associated with multiple Bragg diffraction. The observations are well accounted for by theoretical calculations of the phase delay and of photonic states in the finite-sized systems.

  10. Causal ubiquity in quantum physics a superluminal and local-causal physical ontology

    CERN Document Server

    Neelamkavil, Raphael

    2014-01-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly non-causal processes, something exists processually in extension-motion, between the causal and the non-causal. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That

  11. Diffraction effects in microwave propagation at the origin of superluminal behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Ranfagni, A. [Istituto di Fisica Applicata ' Nello Carrara' , Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze (Italy); Ricci, A.M. [Istituto per le Telecomunicazioni e l' Elettronica della Marina Militare ' Giancarlo Vallauri' (Mariteleradar), Viale Italia 72, 57100 Livorno (Italy); Ruggeri, R. [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Sezione di Firenze, Firenze (Italy)], E-mail: rocco.ruggeri@isc.cnr.it; Agresti, A. [Dipartimento di Fisica dell' Universita di Firenze, Firenze (Italy)

    2008-10-27

    Superluminal behaviors, as evidenced by the presence of forerunners, in advanced position with respect to the main luminal peak, have been revealed in microwave propagation experiments by using a radar technique. The results are interpreted on the basis of (fast) complex waves, usually considered only in the near-field region, but still surviving beyond this limit. Consideration of further diffraction effects, as due to geometrical limitations of the experimental set-up, allows for the obtainment of a plausible description of the results.

  12. SGC Switching Between Subluminal to Superluminal Propagation in V-Type Atom

    Institute of Scientific and Technical Information of China (English)

    HAN Ding-An; GUO Hong; BAI Yan-Feng; SUN Hui; ZENG Ya-Guang

    2006-01-01

    For a V-type three-level atomic system with two closely spaced upper levels, we investigate the light pulse propagation properties with only one laser field. Due to spontaneously generated coherence, the group velocity of the light pulse can be changed from subluminal to superluminal. The effects of the field intensity and the two-upper level splitting on the group velocity are also shown. At last, an analytical expression for the group velocity is given in the case of a weak field.

  13. Visualization of superluminal pulses inside a white light cavity using plane wave spatio temporal transfer functions.

    Science.gov (United States)

    Yum, H N; Jang, Y J; Liu, X; Shahriar, M S

    2012-08-13

    In a white light cavity (WLC), the group velocity is superluminal over a finite bandwidth. For a WLC-based data buffering system we recently proposed, it is important to visualize the behavior of pulses inside such a cavity. The conventional plane wave transfer functions, valid only over space that is translationally invariant, cannot be used for the space inside WLC or any cavity, which is translationally variant. Here, we develop the plane wave spatio temporal transfer function (PWSTTF) method to solve this problem, and produce visual representations of a Gaussian input pulse incident on a WLC, for all times and positions.

  14. Universe of superluminal velocities: tests of astrophysics, from dogma-to reality

    Science.gov (United States)

    Chechelnitsky, A.

    The Barrier of speed of light is the most chained and, perhaps, the most unreasonable Interdiction of the standard (astro) physics and cosmology. Its theoretical bases are speculative and unconvincing, and it actually has not been proved by observations from the very beginning of its promulgations. Moreover, it is gradually increase a stream of the observational data frankly contradicting to the Barrier. This monumental Dogma substantially holds down the initiative of researchers and development of sciences about the Universe. Resolving proofs of absence of the Barrier and real existence of superluminal velocities can come, most likely, from the side of observational astrophysics, when appear fair predictions, based on the alternative theory. Predictions and observational Tests, in particular, are those. The advanced astrophysical researches will lead to accumulation of the precision data and construction of histograms of the velocities observable in the Universe (in the centers of galaxies, AGN, blazàrs, BL Lac, etc), which will show: i) Distribution of the transversal (in a picture plane) superluminal velocities has distinct peaks near to the values specified by the alternative theory: (in G[ -6] Shell) β =v/c: 1.77; 1.48; 1.25; 1.05; 0.88; 0.74; 0.62; 0.52; 0.44; (G[ -7] Shell) β =v/c:: 6.48 ; 5.45; 4.58; 3.85; 3.24; 2.72; 2.29; 1.92; 1.62; (G[ -8] Shell) β =v/c: 23.79; 20.00; 16.82; 14.14; 11.89; 10.00; 8.41; 7.07; 5.95 ii) The same peaks are available (already now, - and it can be shown on the basis of the spectroscopic data) in distribution (histograms) of beam (radial) superluminal velocities (with the same multiplicator M = 2 = 1.1892). iii) The predicted property of discreteness, quantization of superluminal velocities (as well as subluminal) velocities is the exclusive pattern, essentially distinguishing alternative representations (Wave Universe Concept [Chechelnitsky 1980-2004]; see, in particular, the bibliography in Advances in Space Research, v

  15. Fast Transition between High-soft and Low-soft States in GRS 1915+105 Evidence for a Critically Viscous Accretion Flow

    CERN Document Server

    Naik, S; Chakrabarti, S K; Chakrabarti, Sandip K.

    2002-01-01

    We present the results of a detailed analysis of RXTE observations of class $\\omega$ which show an unusual state transition between high-soft and low-soft states in the microquasar GRS 1915+105. Out of about 600 pointed RXTE observations, the source was found to exhibit such state transition only on 16 occasions. An examination of the RXTE/ASM data in conjunction with the pointed observations reveals that these events appeared as a series of quasi-regular dips in two stretches of long duration (about 20 days during each occasions) when hard X-ray and radio flux were very low. The X-ray light curve and color-color diagram of the source during these observations are found to be different from any reported so far. The duration of these dips is found to be of the order of a few tens of seconds with a repetition time of a few hundred seconds. The transition between these dips and non-dips which differ in intensity by a factor of ~ 3.5, is observed to be very fast (~ a few seconds). It is observed that the low-freq...

  16. Geometry of Superluminal Light-Echo Pair Events

    Science.gov (United States)

    Nemiroff, Robert J.

    2017-01-01

    Light echoes, shadows, and ionization fronts can and do move faster than light, both in the lab and out in the cosmos. In general, though, a single observer cannot tell the speed of such echoes without distance information -- unless a very specific geometry arises: the radial component crosses c. The observer then sees this crossing location as the site where a pair of bright light echoes is created or annihilated. This pair event tells the observer that a precise speed occurs, a speed that does not scale with distance and so can potentially be leveraged to reveal geometry and distance information. A few simple scattering surface geometries are shown illuminated by a point flash, including linear and circular filaments. In practice, useful astronomical flash sources include novae and supernovae, although in theory any uniquely varying source of stellar variability could be sufficient.

  17. Discovery of a Super-Luminous Supernova, PTF12dam

    Science.gov (United States)

    Quimby, R. M.; Arcavi, I.; Sternberg, A.; Ben-Ami, S.; Yaron, O.; Gal-Yam, A.; Graham, M.; Cenko, S. B.; Filippenko, A. V.; Perley, D.; Cao, Y.; Kulkarni, S. R.

    2012-05-01

    The Palomar Transient Factory (harvard.edu/abs/2009PASP..121.1395L'>Law et al., 2009; harvard.edu/abs/2009PASP..121.1334R'>Rau et al., 2009) reports the discovery of an optical transient, PTF12dam. The source is located at RA = 14:24:46.20, Dec. = +46:13:48.3 (J2000), which is offset from a r=19.15 mag galaxy detected by the SDSS.

  18. A MULTI-COMPONENT ANALYSIS INDICATES A POSITRONIC MAJOR FLARE IN GRS 1915+105

    Energy Technology Data Exchange (ETDEWEB)

    Punsly, Brian, E-mail: brian.punsly@verizon.net, E-mail: brian.punsly@comdev-usa.com [4014 Emerald Street No. 116, Torrance, CA 90503 (United States)

    2012-02-10

    A modeling strategy that is adapted to the study of synchrotron-self-absorbed plasmoids that was developed for the quasar Mrk 231 by Reynolds et al. is applied to the microquasar GRS 1915+105. The major flare from 1993 December shows spectral evidence of three such self-absorbed components. The analysis yields an estimate of the power that is required to eject the plasmoids from the central engine that is independent of other estimates that exist in the literature for different flares. The technique has an advantage since the absorbed spectrum contains an independent constraint provided by the optical depth at each epoch of observation. The modeling procedure presented here self-consistently determines the dimensions of the radio-emitting plasma from the spectral shape. Thus, structural dimensions are determined analytically that can be much smaller than interferometer beamwidths. A synthesis of the time evolution of the components allows one to address the fundamental uncertainties in previous estimates. First, the plasma is not protonic, but comprises an electron-positron gas. The minimum electron energy is determined to be less than six times the electron rest-mass energy. The analysis also indicates that the plasmoids are ejected from the central engine magnetically dominated. The temporal behavior is one of magnetic energy conversion to mechanical energy as the plasmoids approach equipartition. The time-dependent models bound the impulsive energy flux, Q, required to eject the individual major flare plasmoids from the central engine to, 4.1 Multiplication-Sign 10{sup 37} erg s{sup -1} < Q < 6.1 Multiplication-Sign 10{sup 38} erg s{sup -1}.

  19. The superluminous supernova PS1-11ap: bridging the gap between low and high redshift

    CERN Document Server

    McCrum, M; Kotak, R; Rest, A; Jerkstrand, A; Inserra, C; Rodney, S A; Chen, T -W; Howell, D A; Huber, M E; Pastorello, A; Tonry, J L; Bresolin, F; Kudritzki, R -P; Chornock, R; Berger, E; Smith, K; Botticella, M T; Foley, R J; Fraser, M; Milisavljevic, D; Nicholl, M; Riess, A G; Stubbs, C W; Valenti, S; Wood-Vasey, W M; Wright, D; Young, D R; Drout, M; Czekala, I; Burgett, W S; Chambers, K C; Draper, P; Flewelling, H; Hodapp, K W; Kaiser, N; Magnier, E A; Metcalfe, N; Sweeney, W; Wainscoat, R J

    2013-01-01

    We present optical photometric and spectroscopic coverage of the superluminous supernova (SLSN) PS1-11ap, discovered with the Pan-STARRS1 Medium Deep Survey at z = 0.524. This intrinsically blue transient rose slowly to reach a peak magnitude of M_u = -21.4 mag and bolometric luminosity of 8 x 10^43 ergs^-1 before settling onto a relatively shallow gradient of decline. The observed decline is significantly slower than those of the superluminous type Ic SNe which have been the focus of much recent attention. Spectroscopic similarities with the lower redshift SN2007bi and a decline rate similar to 56Co decay timescale initially indicated that this transient could be a candidate for a pair instability supernova (PISN) explosion. Overall the transient appears quite similar to SN2007bi and the lower redshift object PTF12dam. The extensive data set, from 30 days before peak to 230 days after, allows a detailed and quantitative comparison with published models of PISN explosions. We find that the PS1-11ap data do no...

  20. Slowly fading super-luminous supernovae that are not pair-instability explosions

    CERN Document Server

    Nicholl, M; Jerkstrand, A; Inserra, C; McCrum, M; Kotak, R; Fraser, M; Wright, D; Chen, T -W; Smith, K; Young, D R; Sim, S A; Valenti, S; Howell, D A; Bresolin, F; Kudritzki, R P; Tonry, J L; Huber, M E; Rest, A; Pastorello, A; Tomasella, L; Cappellaro, E; Benetti, S; Mattila, S; Kankare, E; Kangas, T; Leloudas, G; Sollerman, J; Taddia, F; Berger, E; Chornock, R; Narayan, G; Stubbs, C W; Foley, R J; Lunnan, R; Soderberg, A; Sanders, N; Milisavljevic, D; Margutti, R; Kirshner, R P; Elias-Rosa, N; Morales-Garoffolo, A; Taubenberger, S; Botticella, M T; Gezari, S; Urata, Y; Rodney, S; Riess, A G; Scolnic, D; Wood-Vasey, W M; Burgett, W S; Chambers, K; Flewelling, H A; Magnier, E A; Kaiser, N; Metcalfe, N; Morgan, J; Price, P A; Sweeney, W; Waters, C

    2013-01-01

    Super-luminous supernovae that radiate more than 10^44 ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-30 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of 56Ni are synthesized; this isotope decays to 56Fe via 56Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae...

  1. Predictions for signatures of the quark-nova in superluminous supernovae

    CERN Document Server

    Ouyed, Rachid; Jaikumar, Prashanth

    2009-01-01

    [Abridged] Superluminous Supernovae (SN2006gy, SN2005gj, SN2005ap, SN2008fz, SN2003ma) have been a challenge to explain by standard models. We present an alternative scenario involving a quark-nova (QN), an explosive transition of the newly born neutron star to a quark star in which a second explosion (delayed) occurs inside the already expanding ejecta of a normal SN. The reheated SN ejecta can radiate at higher levels for longer periods of time primarily due to reduced adiabatic expansion losses, unlike the standard SN case. Our model is successfully applied to SN2006gy, SN2005gj, SN2005ap, SN2008fz, SN2003ma with encouraging fits to the lightcurves. There are four predictions in our model: (i) superluminous SNe optical lightcurves should show a double-hump with the SN hump at weaker magnitudes occurring days to weeks before the QN; (ii) Two shock breakouts should be observed vis-a-vis one for a normal SN. Depending on the time delay, this would manifest as two distinct spikes in the X-ray region or a broad...

  2. ASASSN-15lh: A Superluminous Ultraviolet Rebrightening Observed by Swift and Hubble

    CERN Document Server

    Brown, Peter J; Cooke, Jeff; Olaes, Melanie; Quimby, Robert M; Baade, Dietrich; Gehrels, Neil; Hoeflich, Peter; Maund, Justyn; Mould, Jeremy; Patat, Ferdinando; Wang, Lifan; Wheeler, J Craig

    2016-01-01

    We present and discuss ultraviolet (UV) and optical photometry from the Ultraviolet/Optical Telescope (UVOT) and X-ray limits from the X-Ray Telescope on Swift and imaging polarimetry and UV/optical spectroscopy with the Hubble Space Telescope (HST) of ASASSN-15lh. It has been classified as a hydrogen-poor superluminous supernova (SLSN I) more luminous than any other supernova observed. From the polarimetry we determine that the explosion was only mildly asymmetric. We find the flux of ASASSN-15lh to increase strongly into the UV, with a UV luminosity a hundred times greater than the hydrogen-rich, UV-bright SLSN II SN~2008es. A late rebrightening -- most prominent at shorter wavelengths -- is seen about two months after the peak brightness, which by itself is as bright as a superluminous supernova. ASASSN-15lh is not detected in the X-rays in individual observations or when the data are summed into two separate bins for the early phase and the rebrightening. The HST UV spectrum during the rebrightening is do...

  3. Two superluminous supernovae from the early universe discovered by the Supernova Legacy Survey

    CERN Document Server

    Howell, D A; Lidman, C; Sullivan, M; Conley, A; Astier, P; Carlberg, C Balland R G; Fouchez, D; Guy, J; Hardin, D; Pain, R; Palanque-Delabrouille, N; Perrett, K; Pritchet, C J; Regnault, N; Rich, J; Ruhlmann-Kleider, V

    2013-01-01

    We present spectra and lightcurves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M_U = -22.7 is one of the most luminous SNe ever observed, and gives a rare glimpse into the restframe ultraviolet where these supernovae put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but based on the supernova spectrum, we estimate it to be at z ~ 1.5. Both supernovae have similar observer-frame griz lightcurves, which map to restframe lightcurves in the U-band and UV, rising in ~ 20 restframe days or longer, and declining over a similar timescale. The lightcurves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra to theoretical models, and identify lines of C II, C III, Fe III, and Mg II in the spectrum of SNLS 06D4eu and SCP 06F6...

  4. Special relativity and superluminal motions: a discussion of some recent experiments

    Energy Technology Data Exchange (ETDEWEB)

    Recami, E. [Istituto Nazionale di Fisica Nucleare, Milan (Italy)]|[Bergamo Univ., Bergamo (Italy). Fac. di Ingegneria]|[State Univ. of Campinas, Campinas (Brazil); Fontana, F. [Pirelli Cavi, Milan (Italy). R and D sector; Garavaglia, R. [Milan Univ., Milan (Italy). Dipt. di Scienze dell' Informazione

    2000-03-01

    Some experiments, performed at Berkeley, Cologne, Florence, Vienna, Orsay and Rennes led to the claim that something seems to travel with a group velocity larger than the speed c of light in vacuum. Various other experimental results seem to point in the same direction. For instance, localized wavelet-type solutions of Maxwell equations have been found, both theoretically and experimentally, that travel with superluminal speed. Even mounic and electronic neutrinos - it has been proposed - might be tachyons, since their square mass appears to be negative. With regard to the first mentioned experiments, it was very recently claimed by Guenter Nimtz that those results with evanescent waves or tunnelling photons - implying superluminal signal and impulse transmission - violate Einstein causality. This note, on the contrary, discusses that all such results do not place relativistic causality in jeopardy, even if they refer to actual tachyonic motions. In fact, special relativity can cope even with also the known paradoxes , devised for faster than light motion, even if this is not widely recognized. Here the paper shows, in detail and rigorously, how to solve the oldest casual paradox. originally proposed by Tolman, which is the kernel of many further tachyon paradoxes. The key to the solution is a careful application of tachyon mechanics, as it unambiguously follows from special relativity.

  5. Extensions of Born’s rule to non-linear quantum mechanics, some of which do not imply superluminal communication

    Science.gov (United States)

    Helou, Bassam; Chen, Yanbei

    2017-08-01

    Nonlinear modifications of quantum mechanics have a troubled history. They were initially studied for many promising reasons: resolving the measurement problem, formulating a theory of quantum mechanics and gravity, and understanding the limits of standard quantum mechanics. However, certain non-linear theories have been experimentally tested and failed. More significantly, it has been shown that, in general, deterministic non-linear theories can be used for superluminal communication. We highlight another serious issue: the distribution of measurement results predicted by non-linear quantum mechanics depends on the formulation of quantum mechanics. In other words, Born’s rule cannot be uniquely extended to non-linear quantum mechanics. We present these generalizations of Born’s rule, and then examine whether some exclude superluminal communication. We determine that a large class do not allow for superluminal communication, but many lack a consistent definition. Nonetheless, we find a single extension of Born’s rule with a sound operational definition, and that does not exhibit superluminal communication. The non-linear time-evolution leading to a certain measurement event is driven by the state conditioned on measurements that lie within the past light cone of that event.

  6. INTEGRAL sees transient activity in the Galactic Bulge: XTE J1751-305 and GRS 1741.9-2853 in outburst

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Kuulkers, E.; Beckmann, V.;

    2009-01-01

    Crab in above-mentioned energy ranges. IBIS/ISGRI did also detect GRS 1741.9-2853 with an average intensity of about 10 mCrab and significance of 6.1 sigma in the 18-40 keV range. The accreting millisecond X-ray pulsar XTE J1751-305 (e.g. Markwardt et al. ApJ 575, L21, 2002) is detected with JEM-X at 15 +/- 6 m......, the closeby and recently discovered accreting millisecond X-ray pulsar IGR J17511-3057 (e.g. ATels #2196-2199) has dimmed to below the INTEGRAL detection levels, whereas it was still detected 6 days earlier at about 12 mCrab averaged over the above-mentioned energy bands. The 3-sigma upper limits are now...... about 5 mCrab and about 2 mCrab between 3-10 keV and 10-25 keV, respectively. We further notice that none of the X-ray bursters in the close source pair SLX 1744-299/300 is significantly detected in JEM-X with 3-sigma upper limits of about 6 mCrab (3-10 keV) and about 3 mCrab (10-25 keV). This seems...

  7. Probing the origin of quasi-periodic oscillations: the short-timescale evolution of phase lags in GRS 1915+105

    CERN Document Server

    Eijnden, Jakob van den; Uttley, Phil

    2016-01-01

    We present a model-independent analysis of the short-timescale energy dependence of low frequency quasi-periodic oscillations (QPOs) in the X-ray flux of GRS 1915+105. The QPO frequency in this source has previously been observed to depend on photon energy, with the frequency increasing with energy for observations with a high ($\\gtrsim 2$ Hz) QPO frequency, and decreasing with energy for observations with a low ($\\lesssim 2$ Hz) QPO frequency. As this observed energy dependence is currently unexplained, we investigate if it is intrinsic to the QPO mechanism by tracking phase lags on (sub)second timescales. We find that the phase lag between two broad energy bands systematically increases for $5$ - $10$ QPO cycles, after which the QPO becomes decoherent, the phase lag resets and the pattern repeats. This shows that the band with the higher QPO frequency is running away from the other band on short timescales, providing strong evidence that the energy dependence of the QPO frequency is intrinsic. We also find ...

  8. Fundamental role of the retarded potential in the electrodynamics of superluminal sources: comment.

    Science.gov (United States)

    Hannay, J H

    2009-10-01

    The commented paper [J. Opt. Soc. Am. A 25, 543 (2008] denies the truth of a standard general formula of electrodynamics [Eq. (6.52) of Jackson, Classical Electrodynamics, 3rd ed. (Wiley, 1999)]). The motivation for challenging orthodoxy is that the formula directly disproves the repeated claim of the commented authors that electromagnetic radiation, under some circumstances, can have unusually long range. The formula they challenge is for the magnetic field: B=Integral over all space of (mu0/4pi)[Curl j]/Range. Instead they advocate a (correct) formula for the vector potential: A=Integral over all space of (mu0/4pi)[j]/Range. However, as one might suppose, the former equation follows as a purely mathematical consequence of taking the curl of the latter equation. This is straightforward to make rigorous in the particular circumstances in question (confined smooth current density j). Therefore by their own formula, the standard one of electrodynamics is confirmed, and the disproof of their long range claim stands.

  9. Magnetar-Powered Supernovae in Two Dimensions. I. Superluminous Supernovae

    CERN Document Server

    Chen, Ke-Jung; Sukhbold, Tuguldur

    2016-01-01

    Previous studies have shown that the radiation emitted by a rapidly rotating magnetar embedded in a young supernova can greatly amplify its luminosity. These one-dimensional studies have also revealed the existence of an instability arising from the piling up of radiatively accelerated matter in a thin dense shell deep inside the supernova. Here we examine the problem in two dimensions and find that, while instabilities cause mixing and fracture this shell into filamentary structures that reduce the density contrast, the concentration of matter in a hollow shell persists. The extent of the mixing depends upon the relative energy input by the magnetar and the kinetic energy of the inner ejecta. The light curve and spectrum of the resulting supernova will be appreciably altered, as will the appearance of the supernova remnant, which will be shellular and filamentary. A similar pile up and mixing might characterize other events where energy is input over an extended period by a centrally concentrated source, e.g...

  10. Superluminal Propagation Caused by Radiative Corrections in a Uniform Electromagnetic Field

    CERN Document Server

    Shiba, Noburo

    2012-01-01

    We consider the effect of radiative corrections on the maximum velocity of propagation of neutral scalar fields in a uniform electromagnetic field. The propagator of neutral scalar fields interacting with charged fields depends on the electromagnetic field through charged particle loops. The kinetic terms of the scalar fields are corrected and the maximum velocity of the scalar particle becomes greater or less than unity. We show that the maximum velocity becomes greater than unity in a simple example, a neutral scalar field coupled with two charged Dirac fields by Yukawa interaction. The maximum velocity depends on the frame of reference and causality is not violated. We discuss the possibility of this superluminal propagation in the Standard Model.

  11. Superluminal Neutrinos and a Curious Phenomenon in the Relativistic Quantum Hamilton-Jacobi Equation

    CERN Document Server

    Matone, Marco

    2011-01-01

    OPERA's results, if confirmed, pose the question of superluminal neutrinos. We investigate the kinematics defined by the quantum version of the relativistic Hamilton-Jacobi equation, i.e. E^2=p^2c^2+m^2c^4+2mQc^2, with Q the quantum potential of the free particle. The key point is that the quantum version of the Hamilton-Jacobi equation is a third-order differential equation, so that it has integration constants which are missing in the Schr\\"odinger and Klein-Gordon equations. In particular, a non-vanishing imaginary part of an integration constant leads to a quantum correction to the expression of the velocity which is curiously in agreement with OPERA's results.

  12. `Superluminal' Photon Propagation in QED in Curved Spacetime is Dispersive and Causal

    CERN Document Server

    Hollowood, Timothy J

    2010-01-01

    It is now well-known that vacuum polarisation in QED can lead to superluminal low-frequency phase velocities for photons propagating in curved spacetimes. In a series of papers, we have shown that this quantum phenomenon is dispersive and have calculated the full frequency dependence of the refractive index, explaining in detail how causality is preserved and various familiar results from quantum field theory such as the Kramers-Kronig dispersion relation and the optical theorem are realised in curved spacetime. These results have been criticised in a recent paper by Akhoury and Dolgov arXiv:1003.6110 [hep-th], who assert that photon propagation is neither dispersive nor necessarily causal. In this note, we point out a series of errors in their work which have led to this false conclusion.

  13. Stimulated generation of superluminal light pulses via four-wave mixing.

    Science.gov (United States)

    Glasser, Ryan T; Vogl, Ulrich; Lett, Paul D

    2012-04-27

    We report on the four-wave mixing of superluminal pulses, in which both the injected and generated pulses involved in the process propagate with negative group velocities. Generated pulses with negative group velocities of up to v(g)=-1/880c are demonstrated, corresponding to the generated pulse's peak exiting the 1.7 cm long medium ≈50 ns earlier than if it had propagated at the speed of light in vacuum, c. We also show that in some cases the seeded pulse may propagate with a group velocity larger than c, and that the generated conjugate pulse peak may exit the medium even earlier than the amplified seed pulse peak. We can control the group velocities of the two pulses by changing the seed detuning and the input seed power.

  14. Can pair-instability supernova models match the observations of superluminous supernovae?

    CERN Document Server

    Kozyreva, Alexandra

    2015-01-01

    An increasing number of so-called superluminous supernovae (SLSNe) are discovered. It is believed that at least some of them with slowly fading light curves originate in stellar explosions induced by the pair instability mechanism. Recent stellar evolution models naturally predict pair instability supernovae (PISNe) from very massive stars at wide range of metallicities (up to Z=0.006, Yusof et al. 2013). In the scope of this study we analyse whether PISN models can match the observational properties of SLSNe with various light curve shapes. Specifically, we explore the influence of different degrees of macroscopic chemical mixing in PISN explosive products on the resulting observational properties. We artificially apply mixing to the 250 Msun PISN evolutionary model from Kozyreva et al. (2014) and explore its supernova evolution with the one-dimensional radiation hydrodynamics code STELLA. The greatest success in matching SLSN observations is achieved in the case of an extreme macroscopic mixing, where all r...

  15. Holographic View of the Brain Memory Mechanism Based on Evanescent Superluminal Photons

    Directory of Open Access Journals (Sweden)

    Takaaki Musha

    2012-08-01

    Full Text Available D. Pollen and M. Trachtenberg proposed the holographic brain theory to help explain the existence of photographic memories in some people. They suggested that such individuals had more vivid memories because they somehow could access a very large region of their memory holograms. Hameroff suggested in his paper that cylindrical neuronal microtubule cavities, or centrioles, function as waveguides for the evanescent photons for quantum signal processing. The supposition is that microtubular structures of the brain function as a coherent fiber bundle set used to store holographic images, as would a fiber-optic holographic system. In this paper, the author proposes that superluminal photons propagating inside the microtubules via evanescent waves could provide the access needed to record or retrieve a quantum coherent entangled holographic memory.

  16. Negative and Superluminal Group Velocity Propagation with Narrow Pulse in a Coaxial Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    OU Xiao-Juan; ZHOU Wei; LI Lin; TENG Li-Hu; FENG Bao-Ying; ZHENG Sheng-Feng; WANG Feng-Wei

    2007-01-01

    We investigate the propagation of electric signal along a spatially periodic impedance mismatched transmission line group. Anomalous dispersion is caused by the periodically mismatched impedance structure and a forbidden band appears near 8 MHz in transmission. The group velocity of the amplitude-modulated signal is augmented up to infinity, even -3.89c (c the speed of light in vacuum) in the forbidden region with the amplitude of the modulated signal increasing. When the carrier sinusoid signal is modulated in amplitude by the modulating sinusoid signal, of which the peak is superimposed with a narrow pulse at fivefold frequency, the superluminal group velocity also occurs. The experiment failed to show whether the propagation velocity of narrow pulse exceeds c or not.

  17. SN 2012au: A GOLDEN LINK BETWEEN SUPERLUMINOUS SUPERNOVAE AND THEIR LOWER-LUMINOSITY COUNTERPARTS

    Energy Technology Data Exchange (ETDEWEB)

    Milisavljevic, Dan; Soderberg, Alicia M.; Margutti, Raffaella; Drout, Maria R.; Marion, G. Howie; Sanders, Nathan E.; Lunnan, Ragnhild; Chornock, Ryan; Berger, Edo; Foley, Ryan J.; Challis, Pete; Kirshner, Robert P.; Dittmann, Jason; Bieryla, Allyson; Kamble, Atish; Chakraborti, Sayan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Fesen, Robert A.; Parrent, Jerod T. [6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Levesque, Emily M., E-mail: dmilisav@cfa.harvard.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); and others

    2013-06-20

    We present optical and near-infrared observations of SN 2012au, a slow-evolving supernova (SN) with properties that suggest a link between subsets of energetic and H-poor SNe and superluminous SNe. SN 2012au exhibited conspicuous Type-Ib-like He I lines and other absorption features at velocities reaching Almost-Equal-To 2 Multiplication-Sign 10{sup 4} km s{sup -1} in its early spectra, and a broad light curve that peaked at M{sub B} = -18.1 mag. Models of these data indicate a large explosion kinetic energy of {approx}10{sup 52} erg and {sup 56}Ni mass ejection of M{sub Ni} Almost-Equal-To 0.3 M{sub Sun} on par with SN 1998bw. SN 2012au's spectra almost one year after explosion show a blend of persistent Fe II P-Cyg absorptions and nebular emissions originating from two distinct velocity regions. These late-time emissions include strong [Fe II], [Ca II], [O I], Mg I], and Na I lines at velocities {approx}> 4500 km s{sup -1}, as well as O I and Mg I lines at noticeably smaller velocities {approx}< 2000 km s{sup -1}. Many of the late-time properties of SN 2012au are similar to the slow-evolving hypernovae SN 1997dq and SN 1997ef, and the superluminous SN 2007bi. Our observations suggest that a single explosion mechanism may unify all of these events that span -21 {approx}< M{sub B} {approx}< -17 mag. The aspherical and possibly jetted explosion was most likely initiated by the core collapse of a massive progenitor star and created substantial high-density, low-velocity Ni-rich material.

  18. Extreme Supernova Models for the Super-luminous Transient ASASSN-15lh

    Science.gov (United States)

    Chatzopoulos, E.; Wheeler, J. C.; Vinko, J.; Nagy, A. P.; Wiggins, B. K.; Even, W. P.

    2016-09-01

    The recent discovery of the unprecedentedly super-luminous transient ASASSN-15lh (or SN 2015L) with its UV-bright secondary peak challenges all the power-input models that have been proposed for super-luminous supernovae. Here we examine some of the few viable interpretations of ASASSN-15lh in the context of a stellar explosion, involving combinations of one or more power inputs. We model the light curve of ASASSN-15lh with a hybrid model that includes contributions from magnetar spin-down energy and hydrogen-poor circumstellar interaction. We also investigate models of pure circumstellar interaction with a massive hydrogen-deficient shell and discuss the lack of interaction features in the observed spectra. We find that, as a supernova, ASASSN-15lh can be best modeled by the energetic core-collapse of an ˜40 M ⊙ star interacting with a hydrogen-poor shell of ˜20 M ⊙. The circumstellar shell and progenitor mass are consistent with a rapidly rotating pulsational pair-instability supernova progenitor as required for strong interaction following the final supernova explosion. Additional energy injection by a magnetar with an initial period of 1-2 ms and magnetic field of 0.1-1 × 1014 G may supply the excess luminosity required to overcome the deficit in single-component models, but this requires more fine-tuning and extreme parameters for the magnetar, as well as the assumption of efficient conversion of magnetar energy into radiation. We thus favor a single-input model where the reverse shock formed in a strong SN ejecta-circumstellar matter interaction following a very powerful core-collapse SN explosion can supply the luminosity needed to reproduce the late-time UV-bright plateau.

  19. A plausible (overlooked) super-luminous supernova in the Sloan digital sky survey stripe 82 data

    Energy Technology Data Exchange (ETDEWEB)

    Kostrzewa-Rutkowska, Zuzanna; Kozłowski, Szymon; Wyrzykowski, Łukasz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Djorgovski, S. George; Mahabal, Ashish A. [California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States); Glikman, Eilat [Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); Koposov, Sergey, E-mail: zkostrzewa@astrouw.edu.pl, E-mail: simkoz@astrouw.edu.pl, E-mail: wyrzykow@astrouw.edu.pl [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-12-01

    We present the discovery of a plausible super-luminous supernova (SLSN), found in the archival data of Sloan Digital Sky Survey (SDSS) Stripe 82, called PSN 000123+000504. The supernova (SN) peaked at m {sub g} < 19.4 mag in the second half of 2005 September, but was missed by the real-time SN hunt. The observed part of the light curve (17 epochs) showed that the rise to the maximum took over 30 days, while the decline time lasted at least 70 days (observed frame), closely resembling other SLSNe of SN 2007bi type. The spectrum of the host galaxy reveals a redshift of z = 0.281 and the distance modulus of μ = 40.77 mag. Combining this information with the SDSS photometry, we found the host galaxy to be an LMC-like irregular dwarf galaxy with an absolute magnitude of M{sub B} = –18.2 ± 0.2 mag and an oxygen abundance of 12+log [O/H]=8.3±0.2; hence, the SN peaked at M {sub g} < –21.3 mag. Our SLSN follows the relation for the most energetic/super-luminous SNe exploding in low-metallicity environments, but we found no clear evidence for SLSNe to explode in low-luminosity (dwarf) galaxies only. The available information on the PSN 000123+000504 light curve suggests the magnetar-powered model as a likely scenario of this event. This SLSN is a new addition to a quickly growing family of super-luminous SNe.

  20. 2 years of INTEGRAL monitoring of GRS 1915+105. I. Multiwavelength coverage with INTEGRAL, RXTE, and the Ryle radio telescope

    DEFF Research Database (Denmark)

    Rodriguez, J.; Hannikainen, D.C.; Shaw, S.E.;

    2008-01-01

    We report the results of simultaneous monitoring observations of the Galactic microquasar GRS 1915+105 with INTEGRAL and RXTE from 3 up to similar to 300 keV, and the Ryle Telescope at 15 GHz. We first identify the classes of variability in which GRS 1915+105 is found, and report some direct...... generalize the fact that a (nonmajor) discrete ejection always occurs, in GRS 1915+105, as a response to an X-ray sequence composed of a spectrally hard X-ray dip terminated by an X-ray spike marking the disappearance of the emission above 18 keV. We identify the trigger of the ejection as the X-ray spike...

  1. Gain-assisted superluminal microwave pulse propagation via four-wave mixing in superconducting phase quantum circuits

    CERN Document Server

    Sabegh, Z Amini; Maleki, M A; Mahmoudi, M

    2015-01-01

    We study the propagation and amplification of a microwave field in a four-level cascade quantum system which is realized in a superconducting phase quantum circuit. It is shown that by increasing the microwave pump tones feeding the system, the normal dispersion switches to the anomalous and the gain-assisted superluminal microwave propagation is obtained in this system. Moreover, it is demonstrated that the stimulated microwave field is generated via four-wave mixing without any inversion population in the energy levels of the system (amplification without inversion) and the group velocity of the generated pulse can be controlled by the external oscillating magnetic fluxes. We also show that in some special set of parameters, the absorption-free superluminal generated microwave propagation is obtained in superconducting phase quantum circuit system.

  2. Green's function of a massless scalar field in curved space-time and superluminal phase velocity of the retarded potential

    CERN Document Server

    Dai, De-Chang

    2012-01-01

    We study a retarded potential solution of a massless scalar field in curved space-time. In a special ansatz for a particle at rest whose magnitude of the (scalar) charge is changing with time, we found an exact analytic solution. The solution indicates that the phase velocity of the retarded potential of a non-moving scalar charge is position dependent, and may easily be greater than the speed of light at a given point. In the case of the Schwarzschild space-time, at the horizon, the phase velocity becomes infinitely faster than the coordinate speed of light at that point. Superluminal phase velocity is relatively common phenomenon, with the the phase velocity of the massive Klein-Gordon field as the best known example. We discuss why it is possible to have modes with superluminal phase velocity even for a massless field.

  3. 超光速:可能与不可能%On the Superluminal Movement:Possible and Impossible?

    Institute of Scientific and Technical Information of China (English)

    黄政新

    2012-01-01

    The OPERA experimental results indicate that neutrinos move even faster than the speed of light,which triggers extensive skepticism with regards of Einstein's assertion that superluminal movement does not exists in nature.This paper first makes a brief review to the history of tachyon(faster-than-light particle) research home and abroad in the past half-century.It then points out that:(1) there is no solid and sufficient reason in Einstein's assertion that superluminal movement does not exists in nature;(2) so far there is no solid experimental foundation for those currently established superluminal theories;(3) a correct superluminal theory should return to special relativity under extreme conditions(i.e.when the velocity approaches the speed of light).%"奥佩拉"(OPERA)实验结果显示中微子运动得比光速还快。这引起许多人对爱因斯坦关于自然界不存在超光速运动这一断言的怀疑。本文回顾了半个世纪以来国内外快子(超光速粒子)研究的简要历史。接着,本文指出:(1)爱因斯坦断言自然界不存在超光速运动是没有充分理由的;(2)所有已建立的超光速理论都没有坚实的实验基础;(3)一个正确的超光理论在极限条件下(当速度趋于光速时)时应当回归狭义相对论。

  4. Optimization of extraction parameters for recovery of a-amylase from the fermented bran of Bacillus circulans GRS313

    Directory of Open Access Journals (Sweden)

    Palit Soumen

    2001-01-01

    Full Text Available The extraction of alpha-amylase in the solid state fermentation of wheat bran by Bacillus circulans GRS313 was optimized. Among various solvents tested, maximum extraction was achieved when 2.5% (v/v glycerol was added. The optimum conditions for extraction were 2.5 hrs soaking time at 30° C under recirculation and agitated condition, which yielded 590 U/g bran of enzyme activity. Whereas under stationary soaking condition the activity of the enzyme was 439.58U/g bran. With repeated wash under the above optimum conditions showed that 600 U/g and 184.2 U/g of enzyme extracted in the 1st and 2nd washes respectively and only 36.84 U/g was recovered in the 3rd wash

  5. A Selection of Giant Radio Sources from NVSS

    CERN Document Server

    Proctor, D D

    2016-01-01

    Results of the application of pattern recognition techniques to the problem of identifying Giant Radio Sources (GRS) from the data in the NVSS catalog are presented and issues affecting the process are explored. Decision-tree pattern recognition software was applied to training set source pairs developed from known NVSS large angular size radio galaxies. The full training set consisted of 51,195 source pairs, 48 of which were known GRS for which each lobe was primarily represented by a single catalog component. The source pairs had a maximum separation of 20 arc minutes and a minimum component area of 1.87 square arc minutes at the 1.4 mJy level. The importance of comparing resulting probability distributions of the training and application sets for cases of unknown class ratio is demonstrated. The probability of correctly ranking a randomly selected (GRS, non-GRS) pair from the best of the tested classifiers was determined to be 97.8 +/- 1.5%. The best classifiers were applied to the over 870,000 candidate p...

  6. Fast Transition between High-soft and Low-soft States in GRS 1915 + 105: Evidence for a Critically Viscous Accretion Flow

    Indian Academy of Sciences (India)

    S. Naik; A. R. Rao; Sandip K. Chakrabarti

    2002-09-01

    We present the results of a detailed analysis of RXTE observations of class (Klein-Wolt et al. 2002) which show an unusual state transition between high-soft and low-soft states in the Galactic microquasar GRS 1915+105. Out of about 600 pointed RXTE observations, the source was found to exhibit such state transition only on 16 occasions. An examination of the RXTE/ASM data in conjunction with the pointed observations reveals that these events appeared as a series of quasi-regular dips in two stretches of long duration (about 20 days during each occasion) when hard X-ray and radio flux were very low. The X-ray light curve and colour-colour diagram of the source during these observations are found to be different from any reported so far. The duration of these dips is found to be of the order of a few tens of seconds with a repetition time of a few hundred seconds. The transition between these dips and non-dips which differ in intensity by a factor of ∼ 3.5, is observed to be very fast (∼ a few seconds). It is observed that the low-frequency narrow QPOs are absent in the power density spectrum (PDS) of the dip and non-dip regions of class and the PDS is a power law in the 0.1 – 10 Hz frequency range. There is a remarkable similarity in the spectral and timing properties of the source during the dip and non-dip regions in this set of observations. These properties of the source are distinctly different from those seen in the observations of other classes. This indicates that the basic accretion disk structure during both dip and non-dip regions of class is similar, but differ only in intensity. To explain these observations, we invoke a model in which the viscosity is very close to critical viscosity and the shock wave is weak or absent.

  7. Two superluminous supernovae from the early universe discovered by the supernova legacy survey

    Energy Technology Data Exchange (ETDEWEB)

    Howell, D. A. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Kasen, D. [Departments of Physics and Astronomy, University of California, Berkeley, Berkeley, CA 94720-7300 (United States); Lidman, C. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Sullivan, M. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-389 (United States); Astier, P.; Balland, C.; Guy, J.; Hardin, D.; Pain, R.; Regnault, N. [LPNHE, CNRS-IN2P3 and University of Paris VI and VII, F-75005 Paris (France); Carlberg, R. G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada); Fouchez, D. [CPPM, CNRS-IN2P3 and University Aix Marseille II, Case 907, F-13288 Marseille Cedex 9 (France); Palanque-Delabrouille, N.; Rich, J.; Ruhlmann-Kleider, V. [DSM/IRFU/SPP, CEA-Saclay, F-91191 Gif-sur-Yvette (France); Perrett, K. [DRDC Ottawa, 3701 Carling Avenue, Ottawa, ON K1A 0Z4 (Canada); Pritchet, C. J. [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6 (Canada)

    2013-12-20

    We present spectra and light curves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae (SNe) discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M{sub U} = –22.7 it is one of the most luminous SNe ever observed, and it gives a rare glimpse into the rest-frame ultraviolet where these SNe put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but on the basis of the SN spectrum, we estimate it to be at z ∼ 1.5. Both SNe have similar observer-frame griz light curves, which map to rest-frame light curves in the U band and UV, rising in ∼20 rest-frame days or longer and declining over a similar timescale. The light curves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra with theoretical models, and we identify lines of C II, C III, Fe III, and Mg II in the spectra of SNLS 06D4eu and SCP 06F6 and find that they are consistent with an expanding explosion of only a few solar masses of carbon, oxygen, and other trace metals. Thus, the progenitors appear to be related to those suspected for SNe Ic. A high kinetic energy, 10{sup 52} erg, is also favored. Normal mechanisms of powering core-collapse or thermonuclear SNe do not seem to work for these SNe. We consider models powered by {sup 56}Ni decay and interaction with circumstellar material, but we find that the creation and spin-down of a magnetar with a period of 2 ms, a magnetic field of 2 × 10{sup 14} G, and a 3 M {sub ☉} progenitor provides the best fit to the data.

  8. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  9. A plausible (overlooked) super-luminous supernova in the SDSS Stripe 82 data

    CERN Document Server

    Kostrzewa-Rutkowska, Zuzanna; Wyrzykowski, Lukasz; Djorgovski, S George; Glikman, Eilat; Mahabal, Ashish A

    2013-01-01

    We present the discovery of a plausible super-luminous supernova (SLSN), found in the archival data of Sloan Digital Sky Survey (SDSS) Stripe 82, called PSN 000123+000504. The supernova peaked at M_g<-21.3 mag in the second half of September 2005, but was missed by the real-time supernova hunt. The observed part of the light curve (17 epochs) showed that the rise to the maximum took over 30 days, while the decline time lasted at least 70 days (observed frame), closely resembling other SLSNe of SN2007bi type. Spectrum of the host galaxy reveals a redshift of z=0.281 and the distance modulus of \\mu=40.77 mag. Combining this information with the SDSS photometry, we found the host galaxy to be an LMC-like irregular dwarf galaxy with the absolute magnitude of M_B=-18.2+/-0.2 mag and the oxygen abundance of 12+log[O/H]=8.3+/-0.2. Our SLSN follows the relation for the most energetic/super-luminous SNe exploding in low-metallicity environments, but we found no clear evidence for SLSNe to explode in low-luminosity ...

  10. On the early-time excess emission in hydrogen-poor superluminous supernovae

    CERN Document Server

    Vreeswijk, Paul M; Gal-Yam, Avishay; De Cia, Annalisa; Perley, Daniel A; Quimby, Robert M; Waldman, Roni; Sullivan, Mark; Yan, Lin; Ofek, Eran O; Fremling, Christoffer; Taddia, Francesco; Sollerman, Jesper; Valenti, Stefano; Arcavi, Iair; Howell, D Andrew; Filippenko, Alexei V; Cenko, S Bradley; Yaron, Ofer; Kasliwal, Mansi M; Cao, Yi; Ben-Ami, Sagi; Horesh, Assaf; Rubin, Adam; Lunnan, Ragnhild; Nugent, Peter E; Laher, Russ; Rebbapragada, Umaa D; Woźniak, Przemysław; Kulkarni, Shrinivas R

    2016-01-01

    We present the light curves of the hydrogen-poor superluminous supernovae (SLSNe-I) PTF12dam and iPTF13dcc, discovered by the (intermediate) Palomar Transient Factory. Both show excess emission at early times and a slowly declining light curve at late times. The early bump in PTF12dam is very similar in duration (~10 days) and brightness relative to the main peak (2-3 mag fainter) compared to those observed in other SLSNe-I, such as SN2006oz, LSQ14bdq and DES14X3taz. In contrast, the long-duration (>30 days) early excess emission in iPTF13dcc, whose brightness competes with that of the main peak, appears to be of a different nature. We construct bolometric light curves for both targets, and fit a variety of light-curve models to both the early bump and main peak in an attempt to understand the nature of these explosions. Even though the slope of the late-time light-curve decline in both SLSNe is suggestively close to that expected from the radioactive decay of $^{56}$Ni and $^{56}$Co, the amount of nickel req...

  11. An extreme ultraviolet excess in the superluminous supernova Gaia16apd reveals a powerful central engine

    CERN Document Server

    Nicholl, M; Margutti, R; Blanchard, P K; Milisavljevic, D; Challis, P; Metzger, B D; Chornock, R

    2016-01-01

    Since the discovery of superluminous supernovae (SLSNe) in the last decade, it has been known that these events exhibit bluer spectral energy distributions than other supernova subtypes, with significant output in the ultraviolet. However, the event Gaia16apd seems to outshine even the other SLSNe at rest-frame wavelengths below $\\sim 3000$ \\AA. Yan et al (2016) have recently presented HST UV spectra and attributed the UV flux to low metallicity and hence reduced line blanketing. Here we present UV and optical light curves over a longer baseline in time, revealing a rapid decline at UV wavelengths despite a typical optical evolution. Combining the published UV spectra with our own optical data, we demonstrate that Gaia16apd has a much hotter continuum than virtually any SLSN at maximum light, but it cools rapidly thereafter and is indistinguishable from the others by $\\sim 10$-15 days after peak. Comparing the equivalent widths of UV absorption lines with those of other events, we show that the excess UV cont...

  12. Gaia16apd -- a link between fast-and slowly-declining type I superluminous supernovae

    CERN Document Server

    Kangas, T; Mattila, S; Lundqvist, P; Fraser, M; Hardy, L K; Stritzinger, M D; Cappellaro, E; Elias-Rosa, N; Harmanen, J; Hsiao, E Y; Kankare, E; Nielsen, M B; Reynolds, T M; Rhodes, L; Somero, A; Wyrzykowski, L

    2016-01-01

    We present ultraviolet, optical and infrared photometry and optical spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd, covering its evolution from 27 d before the $g$-band peak to the nebular phase, including the latest spectrum ever obtained for a fast-declining type Ic SLSN at 150.9 d. Gaia16apd is one of the closest SLSNe known ($z = 0.102\\pm0.001$), with detailed optical and \\emph{Swift} ultraviolet (UV) band observations covering the peak. Gaia16apd is a spectroscopically typical type Ic SLSN, exhibiting the characteristic blue early spectra with O {\\sc ii} absorption, and reaches a peak $M_{g} = -21.8 \\pm 0.1$ mag. However, photometrically it exhibits an evolution intermediate between the fast- and slowly-declining type Ic SLSNe, with an early evolution closer to the fast-declining events. It is unusually UV-bright even for a SLSN, reaching a non-$K$-corrected $M_{uvm2} \\simeq -23.2$ mag, the only other type Ic SLSN with similar UV brightness being SN 2010gx. This event highlights the...

  13. An Extended Model for Interaction Between Left-hand Superluminous Waves and Magnetospheric Electrons

    Institute of Scientific and Technical Information of China (English)

    Xiao Fuliang; Zheng Huinan; Wang Shui

    2005-01-01

    The left-hand superluminous electromagnetic waves, L-O mode and L-X mode, can be excited and observed in the auroral cavity of the Earth during the magnetic storms. The two modes can propagate into outer radiation zone and encounter enhanced resonant interactions with the trapped energetic electrons over a wide range of magnetosphere. A current first-order resonant model is extended to evaluate the stochastic acceleration of electrons by the L-O mode and L-X mode at the higher-order resonance. Similar to the first-order resonance, L-O mode can produce significant acceleration of electrons at the higher harmonic resonances over a wide range of wave normal angles and spatial regions. However, the higher harmonic resonance's contribution for significant electron acceleration by L-X mode is less than that of the first order resonance,with the requirement of higher minimum energies, e.g., ~1 MeV in the outer radiation belt. This indicates that L-O mode may be one of the efficient mechanisms for the stochastic acceleration of electrons within the outer radiation zone.

  14. Studies of the Jet in BL Lacertae. II. Superluminal Alfv\\'en Waves

    CERN Document Server

    Cohen, M H; Arshakian, T G; Clausen-Brown, E; Homan, D C; Hovatta, T; Kovalev, Y Y; Lister, M L; Pushkarev, A B; Richards, J L; Savolainen, T

    2014-01-01

    Ridge lines on the pc-scale jet of the active galactic nucleus BL Lac display transverse patterns that move superluminally downstream. The patterns are not ballistic, but are analogous to waves on a whip. Their apparent speeds $\\beta_\\mathrm{app}$ (units of $c$) range from 4.2 to 13.5, corresponding to $\\beta_\\mathrm{wave}^\\mathrm{gal}= 0.981 - 0.998$ in the galaxy frame. We show that the magnetic field in the jet is well-ordered with a strong transverse component, and assume that it is helical and that the transverse patterns are longitudinal Alfv\\'en waves. The wave-induced transverse speed of the jet is non-relativistic ($\\beta_\\mathrm{tr}^\\mathrm{gal}\\sim 0.09$) and in agreement with our assumption of low-amplitude waves. In 2010 the wave activity subsided and the jet displayed a mild wiggle that had a complex oscillatory behavior. The waves are excited by changes in the position angle of the recollimation shock, in analogy to exciting a wave on a whip by shaking it. Simple models of the system are presen...

  15. Polarimetry of the Superluminous Supernova LSQ14mo: No Evidence for Significant Deviations from Spherical Symmetry

    Science.gov (United States)

    Leloudas, Giorgos; Patat, Ferdinando; Maund, Justyn R.; Hsiao, Eric; Malesani, Daniele; Schulze, Steve; Contreras, Carlos; de Ugarte Postigo, Antonio; Sollerman, Jesper; Stritzinger, Maximilian D.; Taddia, Francesco; Wheeler, J. Craig; Gorosabel, Javier

    2015-12-01

    We present the first polarimetric observations of a Type I superluminous supernova (SLSN). LSQ14mo was observed with VLT/FORS2 at five different epochs in the V band, with the observations starting before maximum light and spanning 26 days in the rest frame (z = 0.256). During this period, we do not detect any statistically significant evolution (\\lt 2σ ) in the Stokes parameters. The average values we obtain, corrected for interstellar polarization in the Galaxy, are Q = -0.01% (±0.15%) and U = -0.50% (±0.14%). This low polarization can be entirely due to interstellar polarization in the SN host galaxy. We conclude that, at least during the period of observations and at the optical depths probed, the photosphere of LSQ14mo does not present significant asymmetries, unlike most lower-luminosity hydrogen-poor SNe Ib/c. Alternatively, it is possible that we may have observed LSQ14mo from a special viewing angle. Supporting spectroscopy and photometry confirm that LSQ14mo is a typical SLSN I. Further studies of the polarization of Type I SLSNe are required to determine whether the low levels of polarization are a characteristic of the entire class and to also study the implications for the proposed explosion models.

  16. Host-Galaxy Properties of 32 Low-Redshift Superluminous Supernovae from the Palomar Transient Factory

    CERN Document Server

    Perley, Daniel A; Yan, Lin; Vreeswijk, Paul; De Cia, Annalisa; Lunnan, Ragnhild; Gal-Yam, Avishay; Yaron, Ofer; Filippenko, Alexei V; Graham, Melissa L; Nugent, Peter E

    2016-01-01

    We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies of all superluminous supernovae (SLSNe) discovered by the Palomar Transient Factory prior to 2013, and derive measurements of their luminosities, star-formation rates, stellar masses, and gas-phase metallicities. We find that Type I (hydrogen-poor) SLSNe are found almost exclusively in low-mass (M 0.5 Z_sun. Extremely low metallicities are not required, and indeed provide no further increase in the relative SLSN rate. Several SLSN-I hosts are undergoing vigorous starbursts, but this may simply be a side effect of metallicity dependence: dwarf galaxies tend to have bursty star-formation histories. Type-II (hydrogen-rich) SLSNe are found over the entire range of galaxy masses and metallicities, and their integrated properties do not suggest a strong preference for (or against) low-mass/low-metallicity galaxies. Two hosts exhibit unusual properties: PTF 10uhf is a Type I SLSN in a massive, luminous infrared galaxy at re...

  17. SN 2012aa - a transient between Type Ibc core-collapse and superluminous supernovae

    CERN Document Server

    Roy, R; Silverman, J M; Pastorello, A; Fransson, C; Drake, A; Taddia, F; Fremling, C; Kankare, E; Kumar, B; Cappellaro, E; Bose, S; Benetti, S; Filippenko, A V; Valenti, S; Nyholm, A; Ergon, M; Sutaria, F; Kumar, B; Pandey, S B; Nicholl, M; Garcia-Alvarez, D; Tomasella, L; Karamehmetoglu, E; Migotto, K

    2016-01-01

    Context: Research on supernovae (SNe) over the past decade has confirmed that there is a distinct class of events which are much more luminous (by $\\sim2$ mag) than canonical core-collapse SNe (CCSNe). These events with visual peak magnitudes $\\lesssim-21$ are called superluminous SNe (SLSNe). Aims: There are a few intermediate events which have luminosities between these two classes. Here we study one such object, SN 2012aa. Methods: The optical photometric and spectroscopic follow-up observations of the event were conducted over a time span of about 120 days. Results: With V_abs at peak ~-20 mag, the SN is an intermediate-luminosity transient between regular SNe Ibc and SLSNe. It also exhibits an unusual secondary bump after the maximum in its light curve. We interpret this as a manifestation of SN-shock interaction with the CSM. If we would assume a $^{56}$Ni-powered ejecta, the bolometric light curve requires roughly 1.3 M_sun of $^{56}$Ni and an ejected mass of ~14 M_sun. This would also imply a high kin...

  18. Polarimetry of the superluminous supernova LSQ14mo: no evidence for significant deviations from spherical symmetry

    CERN Document Server

    Leloudas, Giorgos; Maund, Justyn R; Hsiao, Eric; Malesani, Daniele; Schulze, Steve; Contreras, Carlos; Postigo, Antonio de Ugarte; Sollerman, Jesper; Stritzinger, Maximilian D; Taddia, Francesco; Wheeler, J Craig; Gorosabel, Javier

    2015-01-01

    We present the first polarimetric observations of a Type I superluminous supernova (SLSN). LSQ14mo was observed with VLT/FORS2 at 5 different epochs in the V band, observations starting before maximum light and spanning 26 days in the rest-frame (z=0.256). During this period, we do not detect any statistically significant evolution (< 2$\\sigma$) in the Stokes parameters. The average values we obtain, corrected for interstellar polarisation in the Galaxy, are Q = -0.01% ($\\pm$ 0.15%) and U = - 0.50% ($\\pm$ 0.14%). This low polarisation can be entirely due to interstellar polarisation in the SN host galaxy. We conclude that, at least during the period of observations and at the optical depths probed, the photosphere of LSQ14mo does not present significant asymmetries, unlike most lower-luminosity hydrogen-poor SNe Ib/c. Alternatively, it is possible that we may have observed LSQ14mo from a special viewing angle. Supporting spectroscopy and photometry confirm that LSQ14mo is a typical SLSN I. Further studies ...

  19. Compared propagation characteristics of superluminal and slow light in SOA and EDFA based on rectangle signals

    Science.gov (United States)

    Wang, Fu; Wang, Zhi; Wu, Chongqing; Sun, Zhenchao; Mao, Yaya; Liu, Lanlan; Li, Qiang

    2015-10-01

    Based on the general mechanism of the coherent population oscillations (CPO) in the Semiconductor optical amplifiers (SOA) and Erbium doped fiber amplifiers (EDFA), the group time delay of rectangle signal propagating in the active media is deduced. Compared with the sinusoidal signal, the time delay difference between the fundamental harmonics (FHFD: fundamental harmonic fractional delay) is first investigated in detail for the rectangle signal which is more popularly used in the digital signal systems. The plenty of simulations based on the propagation equations and some experiments for the sinusoidal and rectangle signals are used to analyze the differences and evaluate the slow and superluminal light effects. Furthermore, the time delay/advance always takes place accompanying with the signal distortion, which is evaluated by the total harmonic distortion (THD). The distortion caused by the SOA is smaller than that by the EDFA. A factor Q which is defined to evaluate the trade-off between the FHFD and the THD, shows that higher input power or higher optical gain is better for optical signal processing and optical telecommunications, and the SOA is more suitable for the higher modulation frequency (>10 GHz).

  20. Constraining the ellipticity of strongly magnetized neutron stars powering superluminous supernovae

    Science.gov (United States)

    Moriya, Takashi J.; Tauris, Thomas M.

    2016-07-01

    Superluminous supernovae (SLSNe) have been suggested to be powered by strongly magnetized, rapidly rotating neutron stars which are often called magnetars. In this process, rotational energy of the magnetar is radiated via magnetic dipole radiation and heats the supernova ejecta. However, if magnetars are highly distorted in their geometric shape, rotational energy is mainly lost as gravitational wave radiation and thus such magnetars cannot power SLSNe. By simply comparing electromagnetic and gravitational wave emission time-scales, we constrain upper limits to the ellipticity of magnetars by assuming that they power the observed SLSNe. We find that their ellipticity typically needs to be less than about a few 10-3. This indicates that the toroidal magnetic field strengths in these magnetars are typically less than a few 1016 G so that their distortions remain small. Because light-curve modelling of SLSNe shows that their dipole magnetic field strengths are of the order of 1014 G, the ratio of poloidal to toroidal magnetic field strengths is found to be larger than ˜0.01 in magnetars powering SLSNe.

  1. Constraining the ellipticity of strongly-magnetized neutron stars powering superluminous supernovae

    CERN Document Server

    Moriya, Takashi J

    2016-01-01

    Superluminous supernovae (SLSNe) have been suggested to be powered by strongly-magnetized, rapidly-rotating neutron stars which are often called magnetars. In this process, rotational energy of the magnetar is radiated via magnetic dipole radiation and heats the supernova ejecta. However, if magnetars are highly distorted in their geometric shape, rotational energy is mainly lost as gravitational wave radiation and thus such magnetars cannot power SLSNe. By simply comparing electromagnetic and gravitational wave emission timescales, we constrain upper limits to the ellipticity of magnetars by assuming that they power the observed SLSNe. We find that their ellipticity typically needs to be less than about a few 1e-3. This indicates that the toroidal magnetic field strengths in these magnetars are typically less than a few 1e16 G so that their distortions remain small. Because light-curve modeling of SLSNe shows that their dipole magnetic field strengths are of the order of 1e14 G, the ratio of poloidal to toro...

  2. DES13S2cmm: The First Superluminous Supernova from the Dark Energy Survey

    CERN Document Server

    Papadopoulos, A; Sullivan, M; Nichol, R C; Barbary, K; Biswas, R; Brown, P J; Covarrubias, R A; Finley, D A; Fischer, J A; Foley, R F; Goldstein, D; Gupta, R R; Kessler, R; Kovacs, E; Kuhlmann, S E; Lidman, C; March, M; Nugent, P E; Sako, M; Smith, R C; Spinka, H; Wester, W; Abbott, T M C; Abdalla, F; Allam, S S; Banerji, M; Bernstein, J P; Bernstein, R A; Carnero, A; da Costa, L N; DePoy, D L; Desai, S; Diehl, H T; Eifler, T; Evrard, A E; Flaugher, B; Frieman, J A; Gerdes, D; Gruen, D; Honscheid, K; James, D; Kuehn, K; Kuropatkin, N; Lahav, O; Maia, M A G; Makler, M; Marshall, J L; Merritt, K W; Miller, C J; Miquel, R; Ogando, R; Plazas, A A; Roe, N A; Romer, A K; Rykoff, E; Sanchez, E; Santiago, B X; Scarpine, V; Schubnell, M; Sevilla, I; Santos, M Soares-; Suchyta, E; Swanson, M; Tarle, G; Thaler, J; Tucker, D L; Wechsler, R H; Zuntz, J

    2015-01-01

    We present DES13S2cmm, the first spectroscopically-confirmed superluminous supernova (SLSN) from the Dark Energy Survey (DES). We briefly discuss the data and search algorithm used to find this event in the first year of DES operations, and outline the spectroscopic data obtained from the European Southern Observatory (ESO) Very Large Telescope to confirm its redshift (z = 0.663 +/- 0.001 based on the host-galaxy emission lines) and likely spectral type (type I). Using this redshift, we find M_U_peak = -21.05 +0.10 -0.09 for the peak, rest-frame U-band absolute magnitude, and find DES13S2cmm to be located in a faint, low metallicity (sub-solar), low stellar-mass host galaxy (log(M/M_sun) = 9.3 +/- 0.3); consistent with what is seen for other SLSNe-I. We compare the bolometric light curve of DES13S2cmm to fourteen similarly well-observed SLSNe-I in the literature and find it possesses one of the slowest declining tails (beyond +30 days rest frame past peak), and is the faintest at peak. Moreover, we find the b...

  3. Comments on Musha's theorem that an evanescent photon in the microtubule is a superluminal particle.

    Science.gov (United States)

    Hari, Syamala D

    2014-07-01

    Takaaki Musha's research of high performance quantum computation in living systems is motivated by the theories of Penrose and Hameroff that microtubules in the brain function as quantum computers, and by those of Jibu and Yasue that the quantum states of microtubules depend upon boson condensates of evanescent photons. His work is based on the assumption that the evanescent photons described by Jibu et al. are superluminal and that they are tachyons defined and discussed by well-known physicists such as Sudarshan, Feinberg and Recami. Musha gives a brief justification for the assumption and sometimes calls it a theorem. However, the assumption is not valid because Jibu et al. stated that the evanescent photons have transmission speed smaller than that of light and that their mass is real and momentum is imaginary whereas a tachyon's mass is imaginary and momentum is real. We show here that Musha's proof of the "theorem" has errors and hence his theorem/assumption is not valid. This article is not meant to further discuss any biological aspects of the brain but only to comment on the consistency of the quantum-physical aspects of earlier work by Musha et al.

  4. SN 2015bn: a detailed multi-wavelength view of a nearby superluminous supernova

    CERN Document Server

    Nicholl, M; Smartt, S J; Margutti, R; Kamble, A; Alexander, K D; Chen, T -W; Inserra, C; Arcavi, I; Blanchard, P K; Cartier, R; Chambers, K C; Childress, M J; Chornock, R; Cowperthwaite, P S; Drout, M; Flewelling, H A; Fraser, M; Gal-Yam, A; Galbany, L; Harmanen, J; Holoien, T W -S; Hosseinzadeh, G; Howell, D A; Huber, M E; Jerkstrand, A; Kankare, E; Kochanek, C S; Lin, Z -Y; Lunnan, R; Magnier, E A; Maguire, K; McCully, C; McDonald, M; Metzger, B D; Milisavljevic, D; Mitra, A; Reynolds, T; Saario, J; Shappee, B J; Smith, K W; Valenti, S; Villar, V A; Waters, C; Young, D R

    2016-01-01

    We present observations of SN 2015bn (= PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at $z=0.1136$. As well as being one of the closest SLSNe, it is intrinsically brighter ($M_U\\approx-23.1$) and in a fainter host ($M_B\\approx-16.0$) than other SLSNe at $z\\sim0.1$. We collected the most extensive dataset for an SLSN I to date, including spectroscopy and UV to NIR photometry from $-$50 to +250 d from maximum light. SN 2015bn is a slowly-declining SLSN, but exhibits surprising undulations in the light curve on a timescale of 30-50 d, which are more pronounced in the UV. The spectrum resembles other SLSNe, but our well-sampled data reveal extraordinarily slow evolution except for a rapid transformation between +7 and +30 d. We detect weak features that we tentatively suggest may be hydrogen and helium. At late times, blue colours and a trio of lines around 6000 \\AA\\ seem to distinguish slowly-declining SLSNe from faster ones. We derive physical properties i...

  5. Discussions of the Quantum Superluminality%论量子超光速性

    Institute of Scientific and Technical Information of China (English)

    黄志洵

    2012-01-01

    A.Einstein held an opposite attitude towards Quantum Mechanics(QM),which first appeared in 1926 and reached the top in 1935 when he,together with B.Podolsky,N.Rosen published the EPR thesis and it promotes science development in an opposite side.The EPR thesis is based on Special Relativity(SR).Both SR and EPR deny the possibility of faster-than-light.But QM allows the existence of faster-than-light,agreeing to non-locality of QM is the premise of researching in faster-than light.In 1965,during the interview John Bell confided that his unequality was the outcome of EPR thinking,which denied ultra-space effect under EPR thesis,conditions resulted in quite peculiar correlations that QM predicted.The results of Aspect’s experiments were within expectation that QM has never been wrong now and will not in the future despite of strict requirements.Undoubtedly,the experiments proved that Einstein’s ideas didn’t hold water.In Bell’s opinion,to get rid of the difficulties after the announcement of the Aspect’s experiments,it intends to go back to Lorentz and Poincarè,and assume that ether existed as a referential system in which matters went faster than light.Bell repeatedly pointed out that be wanted to go back to ether because EPR had predicted there was something faster than light in the background.…… Since 1992,it is reported that there have been many successful faster than light experiments.Some of them are based on quantum tunneling effect;some are based on classic physical phenomena such as evanescent waves,anomalous dispersion.And in 2008,D.Salart et.al.performed a experiment using entangled photons between two villages separated by 18km.In conclusion,the speed of the influence of quantum entanglement would have to exceed than of light by at least four orders of magnitude,i.e.10 4 c ~ 10 7 c.Anyway,this experiment was the summation of discussions about the EPR thesis for a long time.For the past 25 years Quantum Superluminality was one subject of my

  6. THE HOST GALAXY OF THE SUPER-LUMINOUS SN 2010gx AND LIMITS ON EXPLOSIVE {sup 56}Ni PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ting-Wan; Smartt, Stephen J.; Kotak, Rubina; McCrum, Matt; Fraser, Morgan [Astrophysics Research Centre, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Bresolin, Fabio; Kudritzki, Rolf-Peter [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Pastorello, Andrea [INAF-Osservatorio Astronomico di Padova, vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Valenti, Stefano [Las Cumbres Observatory Global Telescope Network, Inc., Santa Barbara, CA 93117 (United States)

    2013-02-01

    Super-luminous supernovae have a tendency to occur in faint host galaxies which are likely to have low mass and low metallicity. While these extremely luminous explosions have been observed from z = 0.1 to 1.55, the closest explosions allow more detailed investigations of their host galaxies. We present a detailed analysis of the host galaxy of SN 2010gx (z = 0.23), one of the best studied super-luminous type Ic supernovae. The host is a dwarf galaxy (M{sub g} = -17.42 {+-} 0.17) with a high specific star formation rate. It has a remarkably low metallicity of 12 + log (O/H) = 7.5 {+-} 0.1 dex as determined from the detection of the [O III] {lambda}4363 line. This is the first reliable metallicity determination of a super-luminous stripped-envelope supernova host. We collected deep multi-epoch imaging with Gemini + GMOS between 240 and 560 days after explosion to search for any sign of radioactive {sup 56}Ni, which might provide further insights on the explosion mechanism and the progenitor's nature. We reach griz magnitudes of m{sub AB} {approx} 26, but do not detect SN 2010gx at these epochs. The limit implies that any {sup 56}Ni production was similar to or below that of SN 1998bw (a luminous type Ic SN that produced around 0.4 M{sub Sun} of {sup 56}Ni). The low volumetric rates of these supernovae ({approx}10{sup -4} of the core-collapse population) could be qualitatively matched if the explosion mechanism requires a combination of low-metallicity (below 0.2 Z{sub Sun }), high progenitor mass (>60 M{sub Sun }) and high rotation rate (fastest 10% of rotators).

  7. The jovian anticyclone BA. I. Motions and interaction with the GRS from observations and non-linear simulations

    Science.gov (United States)

    García-Melendo, E.; Legarreta, J.; Sánchez-Lavega, A.; Hueso, R.; Pérez-Hoyos, S.; González, J.; Gómez-Forrellad, J. M.; IOPW Team

    2009-10-01

    A study of the dynamics of the second largest anticyclone in Jupiter, Oval BA, and its red colour change that occurred in late 2005 is presented in a three part study. The first part, this paper, deals with its long-term kinematical and dynamical behaviour monitored since its formation in 2000 to September 2008 using ground-based observations archived at the public International Outer Planet Watch (IOPW) database. The vortex changed its zonal drift velocity from 1.8 m s -1 in the period 2000-2002 to 0.8 m s -1 in 2002-2003, and to 2.5 m s -1 since late 2003. It also migrated southwards by 1.0 ± 0.5° in latitude between 2000 and 2004, remaining afterwards at an almost fixed latitude position. During the period 2000-2007, the oval also changed its triangular-like shape to a more symmetrical one. No latitudinal change was found in the months before the development of a red annulus in its interior. The colour change took place in less than 5 months in 2005-2006 and no red colour feature was observed to have been present or entrained by BA months before the annulus development. After detailed examination of the four encounters between BA and GRS that took place during this 9 year period, we did not detect any noticeable change in its drift rate or in apparent structure associated with the encounters at cloud level. Also, the area of BA did not significantly change in this period. Additionally, we found that BA displays a long-term oscillation of ˜160 days in its longitude position with peak to peak amplitude of 1.2°. Numerical experiments using the global circulation model EPIC reproduce accurately the shape, connecting it to its latitude migration, and morphology of the oval and confirm that no strong interaction between BA and the GRS is possible at least in the current situation.

  8. The superluminous supernova PS1-11ap: bridging the gap between low and high redshift

    Science.gov (United States)

    McCrum, M.; Smartt, S. J.; Kotak, R.; Rest, A.; Jerkstrand, A.; Inserra, C.; Rodney, S. A.; Chen, T.-W.; Howell, D. A.; Huber, M. E.; Pastorello, A.; Tonry, J. L.; Bresolin, F.; Kudritzki, R.-P.; Chornock, R.; Berger, E.; Smith, K.; Botticella, M. T.; Foley, R. J.; Fraser, M.; Milisavljevic, D.; Nicholl, M.; Riess, A. G.; Stubbs, C. W.; Valenti, S.; Wood-Vasey, W. M.; Wright, D.; Young, D. R.; Drout, M.; Czekala, I.; Burgett, W. S.; Chambers, K. C.; Draper, P.; Flewelling, H.; Hodapp, K. W.; Kaiser, N.; Magnier, E. A.; Metcalfe, N.; Price, P. A.; Sweeney, W.; Wainscoat, R. J.

    2014-01-01

    We present optical photometric and spectroscopic coverage of the superluminous supernova (SLSN) PS1-11ap, discovered with the Pan-STARRS1 Medium Deep Survey at z = 0.524. This intrinsically blue transient rose slowly to reach a peak magnitude of Mu = -21.4 mag and bolometric luminosity of 8 × 1043 erg s-1 before settling on to a relatively shallow gradient of decline. The observed decline is significantly slower than those of the SLSNe-Ic which have been the focus of much recent attention. Spectroscopic similarities with the lower redshift SN2007bi and a decline rate similar to 56Co decay time-scale initially indicated that this transient could be a candidate for a pair instability supernova (PISN) explosion. Overall the transient appears quite similar to SN2007bi and the lower redshift object PTF12dam. The extensive data set, from 30 d before peak to 230 d after, allows a detailed and quantitative comparison with published models of PISN explosions. We find that the PS1-11ap data do not match these model explosion parameters well, supporting the recent claim that these SNe are not pair instability explosions. We show that PS1-11ap has many features in common with the faster declining SLSNe-Ic, and the light-curve evolution can also be quantitatively explained by the magnetar spin-down model. At a redshift of z = 0.524, the observer-frame optical coverage provides comprehensive rest-frame UV data and allows us to compare it with the SLSNe recently found at high redshifts between z = 2 and 4. While these high-z explosions are still plausible PISN candidates, they match the photometric evolution of PS1-11ap and hence could be counterparts to this lower redshift transient.

  9. The unexpected, long-lasting, UV rebrightening of the superluminous supernova ASASSN-15lh

    Science.gov (United States)

    Godoy-Rivera, D.; Stanek, K. Z.; Kochanek, C. S.; Chen, Ping; Dong, Subo; Prieto, J. L.; Shappee, B. J.; Jha, S. W.; Foley, R. J.; Pan, Y.-C.; Holoien, T. W.-S.; Thompson, Todd. A.; Grupe, D.; Beacom, J. F.

    2017-04-01

    Given its peak luminosity and early-time spectra, ASASSN-15lh was classified as the most luminous supernova ever discovered. Here, we report a UV rebrightening of ASASSN-15lh observed with Swift during our follow-up campaign. The rebrightening began at t ≃ 90 d (observer frame) after the primary peak and was followed by a ∼120-d long plateau in the bolometric luminosity, before starting to fade again at t ≃ 210 d. ASASSN-15lh rebrightened in the Swift UV bands by ΔmUVW2 ≃ -1.75 mag, ΔmUVM2 ≃ -1.25 mag and ΔmUVW1 ≃ -0.8 mag, but did not rebrighten in the optical bands. Throughout its initial decline, subsequent rebrightening and renewed decline, the spectra did not show evidence of interactions between the ejecta and circumstellar medium such as narrow emission lines. There are hints of weak Hα emission at late-times, but Margutti et al. have shown that it is narrow line emission consistent with star formation in the host nucleus. By fitting a blackbody, we find that during the rebrightening, the effective photospheric temperature increased from TBB ≃ 11 000 K to TBB ≃ 18 000 K. Over the ∼ 550 d since its detection, ASASSN-15lh has radiated ∼1.7 -1.9 × 1052 erg. Although its physical nature remains uncertain, the evolution of ASASSN-15lh's photospheric radius, its radiated energy and the implied event rate, are all more similar to those of H-poor superluminous supernovae than to tidal disruption events.

  10. On the Early-Time Excess Emission in Hydrogen-Poor Superluminous Supernovae

    Science.gov (United States)

    Vreeswijk, Paul M.; Leloudas, Giorgos; Gal-Yam, Avishay; De Cia, Annalisa; Perley, Daniel A.; Quimby, Robert M.; Waldman, Roni; Sullivan, Mark; Yan, Lin; Ofek, Eran O.; hide

    2017-01-01

    We present the light curves of the hydrogen-poor super-luminous supernovae (SLSNe I) PTF 12dam and iPTF 13dcc, discovered by the (intermediate) Palomar Transient Factory. Both show excess emission at early times and a slowly declining light curve at late times. The early bump in PTF 12dam is very similar in duration (approximately 10 days) and brightness relative to the main peak (23 mag fainter) compared to that observed in other SLSNe I. In contrast, the long-duration (greater than 30 days) early excess emission in iPTF 13dcc, whose brightness competes with that of the main peak, appears to be of a different nature. We construct bolometric light curves for both targets, and fit a variety of light-curve models to both the early bump and main peak in an attempt to understand the nature of these explosions. Even though the slope of the late-time decline in the light curves of both SLSNe is suggestively close to that expected from the radioactive decay of 56Ni and 56Co, the amount of nickel required to power the full light curves is too large considering the estimated ejecta mass. The magnetar model including an increasing escape fraction provides a reasonable description of the PTF 12dam observations. However, neither the basic nor the double-peaked magnetar model is capable of reproducing the light curve of iPTF 13dcc. A model combining a shock breakout in an extended envelope with late-time magnetar energy injection provides a reasonable fit to the iPTF 13dcc observations. Finally, we find that the light curves of both PTF 12dam and iPTF 13dcc can be adequately fit with the model involving interaction with the circumstellar medium.

  11. SN 2015BN: A Detailed Multi-wavelength View of a Nearby Superluminous Supernova

    Science.gov (United States)

    Nicholl, M.; Berger, E.; Smartt, S. J.; Margutti, R.; Kamble, A.; Alexander, K. D.; Chen, T.-W.; Inserra, C.; Arcavi, I.; Blanchard, P. K.; Cartier, R.; Chambers, K. C.; Childress, M. J.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Flewelling, H. A.; Fraser, M.; Gal-Yam, A.; Galbany, L.; Harmanen, J.; Holoien, T. W.-S.; Hosseinzadeh, G.; Howell, D. A.; Huber, M. E.; Jerkstrand, A.; Kankare, E.; Kochanek, C. S.; Lin, Z.-Y.; Lunnan, R.; Magnier, E. A.; Maguire, K.; McCully, C.; McDonald, M.; Metzger, B. D.; Milisavljevic, D.; Mitra, A.; Reynolds, T.; Saario, J.; Shappee, B. J.; Smith, K. W.; Valenti, S.; Villar, V. A.; Waters, C.; Young, D. R.

    2016-07-01

    We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter ({M}U≈ -23.1) and in a fainter galaxy ({M}B≈ -16.0) than other SLSNe at z˜ 0.1. We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning -50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30-50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20-30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a ≳ 10 M {}⊙ stripped progenitor exploding with ˜ {10}51 erg kinetic energy, forming a magnetar with a spin-down timescale of ˜20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario—interaction with ˜20 M {}⊙ of dense, inhomogeneous circumstellar material—can be tested with continuing radio follow-up.

  12. ANALYTICAL LIGHT CURVE MODELS OF SUPERLUMINOUS SUPERNOVAE: {chi}{sup 2}-MINIMIZATION OF PARAMETER FITS

    Energy Technology Data Exchange (ETDEWEB)

    Chatzopoulos, E.; Wheeler, J. Craig; Vinko, J. [Department of Astronomy, University of Texas at Austin, Austin, TX (United States); Horvath, Z. L.; Nagy, A., E-mail: manolis@astro.as.utexas.edu [Department of Optics and Quantum Electronics, University of Szeged (Hungary)

    2013-08-10

    We present fits of generalized semi-analytic supernova (SN) light curve (LC) models for a variety of power inputs including {sup 56}Ni and {sup 56}Co radioactive decay, magnetar spin-down, and forward and reverse shock heating due to supernova ejecta-circumstellar matter (CSM) interaction. We apply our models to the observed LCs of the H-rich superluminous supernovae (SLSN-II) SN 2006gy, SN 2006tf, SN 2008am, SN 2008es, CSS100217, the H-poor SLSN-I SN 2005ap, SCP06F6, SN 2007bi, SN 2010gx, and SN 2010kd, as well as to the interacting SN 2008iy and PTF 09uj. Our goal is to determine the dominant mechanism that powers the LCs of these extraordinary events and the physical conditions involved in each case. We also present a comparison of our semi-analytical results with recent results from numerical radiation hydrodynamics calculations in the particular case of SN 2006gy in order to explore the strengths and weaknesses of our models. We find that CS shock heating produced by ejecta-CSM interaction provides a better fit to the LCs of most of the events we examine. We discuss the possibility that collision of supernova ejecta with hydrogen-deficient CSM accounts for some of the hydrogen-deficient SLSNe (SLSN-I) and may be a plausible explanation for the explosion mechanism of SN 2007bi, the pair-instability supernova candidate. We characterize and discuss issues of parameter degeneracy.

  13. SUPERLUMINOUS SUPERNOVAE POWERED BY MAGNETARS: LATE-TIME LIGHT CURVES AND HARD EMISSION LEAKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. Q.; Wang, L. J.; Dai, Z. G. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, X. F., E-mail: dzg@nju.edu.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2015-01-20

    Recently, research performed by two groups has revealed that the magnetar spin-down energy injection model with full energy trapping can explain the early-time light curves of SN 2010gx, SN 2013dg, LSQ12dlf, SSS120810, and CSS121015 but fails to fit the late-time light curves of these superluminous supernovae (SLSNe). These results imply that the original magnetar-powered model is challenged in explaining these SLSNe. Our paper aims to simultaneously explain both the early- and late-time data/upper limits by considering the leakage of hard emissions. We incorporate quantitatively the leakage effect into the original magnetar-powered model and derive a new semianalytical equation. Comparing the light curves reproduced by our revised magnetar-powered model with the observed data and/or upper limits of these five SLSNe, we found that the late-time light curves reproduced by our semianalytical equation are in good agreement with the late-time observed data and/or upper limits of SN 2010gx, CSS121015, SN 2013dg, and LSQ12dlf and the late-time excess of SSS120810, indicating that the magnetar-powered model might be responsible for these SLSNe and that the gamma-ray and X-ray leakages are unavoidable when the hard photons were down-Comptonized to softer photons. To determine the details of the leakage effect and unveil the nature of SLSNe, more high-quality bolometric light curves and spectra of SLSNe are required.

  14. Host-galaxy Properties of 32 Low-redshift Superluminous Supernovae from the Palomar Transient Factory

    Science.gov (United States)

    Perley, D. A.; Quimby, R. M.; Yan, L.; Vreeswijk, P. M.; De Cia, A.; Lunnan, R.; Gal-Yam, A.; Yaron, O.; Filippenko, A. V.; Graham, M. L.; Laher, R.; Nugent, P. E.

    2016-10-01

    We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies of all superluminous supernovae (SLSNe) discovered by the Palomar Transient Factory prior to 2013 and derive measurements of their luminosities, star formation rates, stellar masses, and gas-phase metallicities. We find that Type I (hydrogen-poor) SLSNe (SLSNe I) are found almost exclusively in low-mass ({M}* \\lt 2× {10}9 {M}ȯ ) and metal-poor (12 + log10[O/H] \\lt 8.4) galaxies. We compare the mass and metallicity distributions of our sample to nearby galaxy catalogs in detail and conclude that the rate of SLSNe I as a fraction of all SNe is heavily suppressed in galaxies with metallicities ≳ 0.5 {Z}ȯ . Extremely low metallicities are not required and indeed provide no further increase in the relative SLSN rate. Several SLSN I hosts are undergoing vigorous starbursts, but this may simply be a side effect of metallicity dependence: dwarf galaxies tend to have bursty star formation histories. Type II (hydrogen-rich) SLSNe (SLSNe II) are found over the entire range of galaxy masses and metallicities, and their integrated properties do not suggest a strong preference for (or against) low-mass/low-metallicity galaxies. Two hosts exhibit unusual properties: PTF 10uhf is an SLSN I in a massive, luminous infrared galaxy at redshift z = 0.29, while PTF 10tpz is an SLSN II located in the nucleus of an early-type host at z = 0.04.

  15. The Unexpected, Long-Lasting, UV Rebrightening of the Super-Luminous Supernova ASASSN-15lh

    Science.gov (United States)

    Godoy-Rivera, D.; Stanek, K. Z.; Kochanek, C. S.; Chen, Ping; Dong, Subo; Prieto, J. L.; Shappee, B. J.; Jha, S. W.; Foley, R. J.; Pan, Y.-C.; Holoien, T. W.-S.; Thompson, Todd. A.; Grupe, D.; Beacom, J. F.

    2017-01-01

    Given its peak luminosity and early-time spectra, ASASSN-15lh was classified as the most luminous supernova (SN) ever discovered (Dong et al. 2016).. Here we report a UV rebrightening of ASASSN-15lh observed with Swift during our follow-up campaign. The rebrightening began at t ≃ 90 days (observer frame) after the primary peak and was followed by a ˜120-day long plateau in the bolometric luminosity, before starting to fade again at t ≃ 210 days. ASASSN-15lh rebrightened in the Swift UV bands by ΔmUVW2 ≃ -1.75 mag, ΔmUVM2 ≃ -1.25 mag, and ΔmUVW1 ≃ -0.8 mag, but did not rebrighten in the optical bands. Throughout its initial decline, subsequent rebrightening, and renewed decline, the spectra did not show evidence of interactions between the ejecta and circumstellar medium (CSM) such as narrow emission lines. There are hints of weak Hα emission at late-times, but Margutti et al. (2016) have shown that it is narrow line emission consistent with star formation in the host nucleus. By fitting a blackbody we find that during the rebrightening the effective photospheric temperature increased from TBB ≃ 11000 K to TBB ≃ 18000 K. Over the ˜ 550 days since its detection, ASASSN-15lh has radiated ˜1.7 - -1.9 × 1052 ergs. Although its physical nature remains uncertain, the evolution of ASASSN-15lh's photospheric radius, its radiated energy, and the implied event rate, are all more similar to those of H-poor superluminous supernovae (SLSNe-I) than to tidal disruption events (TDEs).

  16. Investigating the connection between Quasi Periodic Oscillations and spectral components with NuSTAR data of GRS 1915+105

    CERN Document Server

    Jassal, Anjali Rao; S, Mithun N P; Misra, Ranjeev

    2015-01-01

    The low frequency quasi periodic oscillations (QPOs) are commonly observed during hard states of black hole binaries. Several studies have established various observational/empirical correlations between spectral parameters and QPO properties, indicating a close link between the two. However, the exact mechanism of generation of QPO is not yet well understood. In this paper, we present our attempts to comprehend the connection between the spectral components and the low frequency QPO observed in GRS 1915+105 using the data from NuSTAR. Detailed spectral modeling as well as the presence of the low frequency QPO and its energy dependence during this observation have been reported by Miller et al. (2013) and Zhang et al. (2015) respectively. We investigate the compatibility of the spectral model and energy dependence of the QPO by simulating light curves in various energy bands for small variation of the spectral parameters. The basic concept here is to establish connection, if any, between the QPO and the varia...

  17. GRS 1739-278 observed at very low luminosity with XMM-Newton and NuSTAR

    CERN Document Server

    Fuerst, F; Yamaoka, K; Dauser, T; Miller, J M; Clavel, M; Corbel, S; Fabian, A C; Garcia, J; Harrison, F A; Loh, A; Kaaret, P; Kalemci, E; Migliari, S; Miller-Jones, J C A; Pottschmidt, K; Rahoui, F; Rodriguez, J; Stern, D; Stuhlinger, M; Walton, D J; Wilms, J

    2016-01-01

    We present a detailed spectral analysis of XMM-Newton and NuSTAR observations of the accreting transient black hole GRS 1739-278 during a very faint low hard state at ~0.02% of the Eddington luminosity (for a distance of 8.5 kpc and a mass of 10 M_sun ). The broad-band X-ray spectrum between 0.5-60 keV can be well-described by a power law continuum with an exponential cutoff. The continuum is unusually hard for such a low luminosity, with a photon index of Gamma = 1.39 +/- 0.04. We find evidence for an additional reflection component from an optically thick accretion disk at the 98% likelihood level. The reflection fraction is low with R_refl = 0.043(+0.033,-0.023). In combination with measurements of the spin and inclination parameters made with NuSTAR during a brighter hard state by Miller and co-workers, we seek to constrain the accretion disk geometry. Depending on the assumed emissivity profile of the accretion disk, we find a truncation radius of 15-35 Rg (5-12 R_ISCO ) at the 90% confidence limit. Thes...

  18. Identification of a seventeen-day timescale in X-ray observations of GRS 1915+105

    CERN Document Server

    Greenhough, J; Chaty, S; Dendy, R O; Rowlands, G

    2003-01-01

    Measurement of the energy emitted from accreting astrophysical systems provides an observational constraint on the plasma processes that may be operating within the disk. Here we examine the continual time variation over the past six years of the total X-ray flux from the microquasar GRS 1915+105. The application of differencing and rescaling techniques shows that the small amplitude fluctuations are self-similar on timescales up to 17 +/- 3 days, but not beyond. This is confirmed by the wavelet transform of the X-ray time-series. The newly-observed 17-day timescale in the X-ray fluctuations is half the measured binary orbital period of this system (33.5 +/- 1.5 days). While this may be coincidental, it is possible that these two timescales may be linked by, for example, a turbulent cascade in the accretion disk driven by a tidally-induced two-armed spiral shock corotating with the binary system. Self-similarity is found only in the ever-present small fluctuations, and not in the larger-amplitude fluctuations...

  19. Nonlinear time series analysis of the light curves from the black hole system GRS1915+105

    Institute of Scientific and Technical Information of China (English)

    K.P Harikrishnan; Ranjeev Misra; G.Ambika

    2011-01-01

    GRS 1915+105 is a prominent black hole system exhibiting variability over a wide range of time scales and its observed light curves have been classified into 12 temporal states. Here we undertake a complete analysis of these light curves from all the states using various quantifiers from nonlinear time series analysis, such as the correlation dimension (D2), the correlation entropy (K2), singular value decomposition (SVD) and the multifractal spectrum (f(α) spectrum). An important aspect of our analysis is that, for estimating these quantifiers, we use algorithmic schemes which we have recently proposed and successfully tested on synthetic as well as practical time series from various fields. Though the schemes are based on the conventional delay embedding technique, they are automated so that the above quantitative measures can be computed using conditions prescribed by the algorithm and without any intermediate subjective analysis. We show that nearly half of the 12 temporal states exhibit deviation from randomness and their complex temporal behavior could be approximated by a few (three or four) coupled ordinary nonlinear differential equations. These results could be important for a better understanding of the processes that generate the light curves and hence for modeling the temporal behavior of such complex systems.To our knowledge, this is the first complete analysis of an astrophysical object (let alone a black hole system) using various techniques from nonlinear dynamics.

  20. Economic and Thermodynamic Analysis for Preliminary Design of Dry Steam Geothermal Power Plant (GPP) with Multifarious Gas Removal System (GRS) in Kamojang, West Java, Indonesia

    Science.gov (United States)

    Damar Pranadi, Aloysius; Sihana; Suryopratomo, Kutut; Rahmatika Salis, Fiki

    2016-09-01

    Indonesia has great number of geothermal potential separated by two kind of potential, 16.13 GW for high enthalpy and 7.88 GW for low enthalpy speculative resources [4]. In the end of 2013, Ministry of Energy and Mineral Resources stated that Geothermal Power Plant (GPP) in Indonesia have been built about 1.34 GW in capacity and wanted to seriously develop geothermal potential up to 6.64 GW by 2025 [8]. Cost is one of famous obstacle in Indonesia's GPP Development. To reduce grand total cost of GPP, this paper will present the relation between thermodynamic and economic analysis in purpose to find the most economical gas removal system in GPP. By gleaning data at Kamojang Steam Field on behalf of PT Pertamina Geothermal Energy, this study will thermodynamically analyze and calculate a GPP preliminary design with software, named as Cycle Tempo 5.0. In additional, writers create motive steam calculator (based on C++ language) to enhance thermodynamic analysis for gas removal system (GRS) and adapted the results in Cycle Tempo 5.0. After thermodynamic analysis has been done, economic study will be undertaken by Net Present Value Analysis to compare the utilization cost of three different GRS and find which kind of GRS is more economical for nearly 30 years operation. For the result, Dual LRVP has higher performance than the others, spend less utilization cost and more economical for nearly 30 years operation. Moreover, the economic analysis for replacement of gas removal system shown in this paper too. In conclusion, GPP with Dual LRVP is proper to be developed in the future Geothermal Power Plant or to replace the existing GRS in some existing GPP in Indonesia.

  1. Latest Progress on Propagation Characteristics of Superluminous Waves and their Gyroresonance with Energetic Particles%超光速电磁波的传播特性及与高能粒子相互作用研究的新进展

    Institute of Scientific and Technical Information of China (English)

    肖伏良; 何兆国; 陈良旭; 贺艺华; 杨昶

    2011-01-01

    超光速(相速度大于光速)电磁波是广泛存在于空间等离子中的高频电磁波,总结了超光速电磁波的产生机制-回旋微波激射不稳定性,介绍了超光速波在地球磁层中的传播特性,分析了其从高纬极光源区传播到低纬区域的基本原因:磁暴时由于等离子层硕压缩,超光速波传播时不会遇上反射,从而能向下传播.重点介绍了超光速波产生的地球辐射带区域高能电子的随机加速与投掷角扩散过程.发现超光速波能量扩散过程一般大于投掷角扩散过程,在合适的条件下超光速波对高投掷角的高能电子主要起随机加速作用,而对低投掷角的高能电子主要起投掷角扩散作用.这些最新进展有助于进一步了解超光速电磁波的激发与传播特性,以及地球辐射带高能电子的动力学行为.%Superluminous (the phase speed higher than the speed of light) electromagnetic waves are widely present in the space plasma with high frequencies. Here, we briefly introduce their generation mechanism-Cyclotron Maser Instability ( CMI). We present discussion on the propagating characteristics of superluminous waves in the Earth's magnetosphere. During high geomagnetic activity, since the plasmapause position moves inward closer to the Earth, the superluminous waves can propagate from their source cavity downward and even through the equatorial plane due to no reflection. We focus on pitch angle scattering and stochastic acceleration of energetic electrons induced by superluminous waves in the radiation belts. Current works show that energy diffusion resulting from such waves is generally higher than pitch angle scattering. Under appropriate conditions, superluminous waves may contribute to both the stochastic acceleration of electrons with larger pitch angle and the loss process of electrons with smaller pitch angles. These recent progresses provide further understanding of the instability and propagation of

  2. Investigation on the anisotropic mechanical behaviour of the Callovo-Oxfordian clay rock within the framework of ANDRA/GRS cooperation programme. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chun-Liang [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koeln (Germany); Armand, Gilles; Conil, Nathalie [French Agence Nationale Pour la Gestion de Dechets Radioactifs (ANDRA), Chatenay-Malabry (France)

    2015-01-15

    An underground repository for disposal of radioactive waste is planned to be constructed in the sedimentary Callovo-Oxfordian argillaceous formation (COX) in France /AND 05/. The clay rock exhibits inherent anisotropy with bedding structure, which leads to directional dependences of the rock properties (e.g. mineralogical, physical, mechanical, hydraulic, thermal, etc.) with respect to the bedding planes. For the design of the repository and the assessment of its safety during the operation and post-closure phases it is necessary to characterise and predict the anisotropic properties and processes in the host rock, particularly in the excavation damaged zone (EDZ) near the openings. Within the framework of the bilateral cooperation agreement between the French National Radioactive Waste Management Agency (ANDRA) and the German Federal Ministry of Economics and Technology (BMWi), concerning the research activities in the Meuse/Haute-Marne Underground Research Laboratory (MHM-URL), a joint research programme was initiated by ANDRA and GRS in 2013 to investigate mechanical anisotropy of the COX clay rock for the purpose of precise characterization, better understanding and reliable prediction of the development of EDZ around the repository. This programme was funded by ANDRA under contract number 059844 and performed by GRS during the time period of November 2013 to December 2014. GRS gratefully acknowledges the financial support from and the fruitful cooperation with ANDRA.

  3. Helmholtz theorem and the v-gauge in the problem of superluminal and instantaneous signals in classical electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chubykalo, Andrew; Espinoza, Augusto; Flores, Rolando Alvarado; Rodriguez, Alejandro Gutierrez [Universidad Autonoma de Zacatecas (Mexico). Unidad Academica de Fisica

    2011-07-01

    In this work we substantiate the applying of the Helmholtz vector decomposition theorem (H-theorem) to vector fields in classical electrodynamics. Using the H-theorem, within the framework of the two-parameter Lorentz-like gauge (so called V-gauge), we show that two kinds of magnetic vector potentials exist: one of them (solenoidal) can act exclusively with the velocity of light C and the other one (irrotational) with an arbitrary finite velocity V (including a velocity more than C). We show also that the irrotational component of the electric field has a physical meaning and can propagate exclusively instantaneously. We provide a theoretical rationale (within the framework of classical electrodynamics) of a series of well-known recent experiments, which detected superluminal signals. Finally, we affirm that applying the Helmholtz theorem to classical electrodynamics allows to conclude that in classical electrodynamics so called instantaneous action at a distance with the infinite velocity of interaction can take place as well as (within the framework of the v-gauge-theory) the superluminal action with a finite velocity of interaction. (author)

  4. Superluminous supernova 2015bn in the nebular phase: evidence for the engine-powered explosion of a stripped massive star

    CERN Document Server

    Nicholl, M; Margutti, R; Chornock, R; Blanchard, P K; Jerkstrand, A; Smartt, S J; Arcavi, I; Challis, P; Chambers, K C; Chen, T -W; Cowperthwaite, P S; Gal-Yam, A; Hosseinzadeh, G; Howell, D A; Inserra, C; Kankare, E; Magnier, E A; Maguire, K; Mazzali, P A; McCully, C; Milisavljevic, D; Smith, K W; Taubenberger, S; Valenti, S; Wainscoat, R J; Yaron, O; Young, D R

    2016-01-01

    We present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova SN 2015bn, at redshift z=0.1136, spanning +250-400 d after maximum light. The light curve exhibits a steepening in the decline rate from 1.4 mag/(100 d) to 1.7 mag/(100 d), suggestive of a significant decrease in the opacity. This change is accompanied by a transition from a blue continuum superposed with photospheric absorption lines to a nebular spectrum dominated by emission lines of oxygen, calcium and magnesium. There are no obvious signatures of circumstellar interaction or large nickel mass. We show that the spectrum at +400 d is virtually identical to a number of energetic Type Ic supernovae such as SN 1997dq, SN 2012au, and SN 1998bw, indicating similar core conditions and strengthening the link between `hypernovae'/long gamma-ray bursts and superluminous supernovae. A single explosion mechanism may unify these events that span absolute magnitudes of -22 < M_B < -17. Both the light curve and spectrum...

  5. Spectroscopy of superluminous supernova host galaxies. A preference of hydrogen-poor events for extreme emission line galaxies

    CERN Document Server

    Leloudas, G; Kruehler, T; Gorosabel, J; Christensen, L; Mehner, A; Postigo, A de Ugarte; Amorin, R; Thoene, C C; Anderson, J P; Bauer, F E; Gallazzi, A; Helminiak, K G; Hjorth, J; Ibar, E; Malesani, D; Morell, N; Vinko, J; Wheeler, J C

    2014-01-01

    Superluminous supernovae (SLSNe) were only discovered recently due to their preference for occurring in faint dwarf galaxies. Understanding why stellar evolution yields different types of stellar explosions in these environments is fundamental in order to both uncover the elusive progenitors of SLSNe and to study star formation in dwarf galaxies. In this paper, we present the first results of our project to study SUperluminous Supernova Host galaxIES (SUSHIES), focusing on the sample for which we have obtained spectroscopy. We show that SLSNe-I and SLSNe-R (hydrogen-poor) often (~50% in our sample) occur in a class of galaxies that is known as Extreme Emission Line Galaxies (EELGs). The probability of this happening by chance is negligible and we therefore conclude that the extreme environmental conditions and the SLSN phenomenon are related. In contrast, SLSNe-II (hydrogen-rich) occur in more massive, more metal-rich galaxies with softer radiation fields. Therefore, if SLSNe-II constitute a uniform class, th...

  6. An Infinitesimally Superluminal Neutrino is Left-Handed, Conserves Lepton Number and Solves the Autobahn Paradox (Illustrative Discussion)

    CERN Document Server

    Jentschura, U D

    2012-01-01

    Consider a gedanken experiment in which a massive left-handed neutrino, traveling on an autobahn at a speed of v=0.999c is overtaken by a tuned-up Cagiva V-Raptor 1000 traveling at a speed of 0.999999c. The biker, looking back, would see a right-handed neutrino. Unless one invokes exotic mechanisms like a sterile neutrino, this "autobahn paradox" implies that a massive subluminal (tardyonic) neutrino necessarily has to be a Majorana particle, i.e, equal to its own antiparticle. In turn, this would require us to assign the same lepton number to charged leptons and antileptons, essentially voiding the concept of lepton number. By contrast, an infinitesimally superluminal (tachyonic) neutrino is not equal to its own antiparticle and allows us to assign proper lepton number, just as if the neutrino were a Weyl particle. Furthermore, if Lorentz symmetry holds, then an infinitesimally tachyonic neutrino remains superluminal upon Lorentz transformation, which implies that it is impossible to overtake it in a gedanke...

  7. Sources

    OpenAIRE

    2015-01-01

    SOURCES MANUSCRITES Archives nationales Rôles de taille 1768/71 Z1G-344/18 Aulnay Z1G-343a/02 Gennevilliers Z1G-340/01 Ivry Z1G-340/05 Orly Z1G-334c/09 Saint-Remy-lès-Chevreuse Z1G-344/18 Sevran Z1G-340/05 Thiais 1779/80 Z1G-391a/18 Aulnay Z1G-380/02 Gennevilliers Z1G-385/01 Ivry Z1G-387b/05 Orly Z1G-388a/09 Saint-Remy-lès-Chevreuse Z1G-391a/18 Sevran Z1G-387b/05 Thiais 1788/89 Z1G-451/18 Aulnay Z1G-452/21 Chennevières Z1G-443b/02 Gennevilliers Z1G-440a/01 Ivry Z1G-452/17 Noiseau Z1G-445b/05 ...

  8. SN 2012aa: A transient between Type Ibc core-collapse and superluminous supernovae

    Science.gov (United States)

    Roy, R.; Sollerman, J.; Silverman, J. M.; Pastorello, A.; Fransson, C.; Drake, A.; Taddia, F.; Fremling, C.; Kankare, E.; Kumar, B.; Cappellaro, E.; Bose, S.; Benetti, S.; Filippenko, A. V.; Valenti, S.; Nyholm, A.; Ergon, M.; Sutaria, F.; Kumar, B.; Pandey, S. B.; Nicholl, M.; Garcia-Álvarez, D.; Tomasella, L.; Karamehmetoglu, E.; Migotto, K.

    2016-12-01

    Context. Research on supernovae (SNe) over the past decade has confirmed that there is a distinct class of events which are much more luminous (by 2 mag) than canonical core-collapse SNe (CCSNe). These events with visual peak magnitudes ≲-21 are called superluminous SNe (SLSNe). The mechanism that powers the light curves of SLSNe is still not well understood. The proposed scenarios are circumstellar interaction, the emergence of a magnetar after core collapse, or disruption of a massive star through pair production. Aims: There are a few intermediate events which have luminosities between these two classes. They are important for constraining the nature of the progenitors of these two different populations and their environments and powering mechanisms. Here we study one such object, SN 2012aa. Methods: We observed and analysed the evolution of the luminous Type Ic SN 2012aa. The event was discovered by the Lick Observatory Supernova Search in an anonymous galaxy (z ≈ 0.08). The optical photometric and spectroscopic follow-up observations were conducted over a time span of about 120 days. Results: With an absolute V-band peak of - 20 mag, the SN is an intermediate-luminosity transient between regular SNe Ibc and SLSNe. SN 2012aa also exhibits an unusual secondary bump after the maximum in its light curve. For SN 2012aa, we interpret this as a manifestation of SN-shock interaction with the circumstellar medium (CSM). If we assume a 56Ni-powered ejecta, the quasi-bolometric light curve requires roughly 1.3 M⊙ of 56Ni and an ejected mass of 14M⊙. This also implies a high kinetic energy of the explosion, 5.4 × 1051 erg. On the other hand, the unusually broad light curve along with the secondary peak indicate the possibility of interaction with CSM. The third alternative is the presence of a central engine releasing spin energy that eventually powers the light curve over a long time. The host of SN 2012aa is a star-forming Sa/Sb/Sbc galaxy. Conclusions

  9. Superluminous Supernovae as Standardizable Candles and High-redshift Distance Probes

    Science.gov (United States)

    Inserra, C.; Smartt, S. J.

    2014-12-01

    We investigate the use of type Ic superluminous supernovae (SLSN Ic) as standardizable candles and distance indicators. Their appeal as cosmological probes stems from their remarkable peak luminosities, hot blackbody temperatures, and bright rest-frame ultraviolet emission. We present a sample of 16 published SLSN, from redshifts 0.1 to 1.2, and calculate accurate K corrections to determine uniform magnitudes in 2 synthetic rest-frame filter bandpasses with central wavelengths at 400 nm and 520 nm. At 400 nm, we find an encouragingly low scatter in their uncorrected, raw mean magnitudes with M(400) = -21.86 ± 0.35 mag for the full sample of 16 objects. We investigate the correlation between their decline rates and peak magnitude and find that the brighter events appear to decline more slowly. In a manner similar to the Phillips relation for type Ia SNe (SNe Ia), we define a ΔM 20 decline relation. This correlates peak magnitude and decline over 20 days and can reduce the scatter in standardized peak magnitudes to ±0.22 mag. We further show that M(400) appears to have a strong color dependence. Redder objects are fainter and also become redder faster. Using this peak magnitudecolor evolution relation, a surprisingly low scatter of between ±0.08 mag and ±0.13 mag can be found in peak magnitudes, depending on sample selection. However, we caution that only 8 to 10 objects currently have enough data to test this peak magnitudecolor evolution relation. We conclude that SLSN Ic are promising distance indicators in the high-redshift universe in regimes beyond those possible with SNe Ia. Although the empirical relationships are encouraging, the unknown progenitor systems, how they may evolve with redshift, and the uncertain explosion physics are of some concern. The two major measurement uncertainties are the limited numbers of low-redshift, well-studied objects available to test these relationships and internal dust extinction in the host galaxies.

  10. DES13S2cmm: the first superluminous supernova from the Dark Energy Survey

    Energy Technology Data Exchange (ETDEWEB)

    Papadopoulos, A.; D’Andrea, C. B.; Sullivan, M; Nichol, R. C.; Barbary, K.; Biswas, R.; Brown, P. J.; Covarrubias, R. A.; Finley, D. A.; Fischer, J. A.; Gupta, R. R.; Kovacs, E.; Kuhlmann, S. E.; Spinka, H.; Bernstein, J. P.

    2015-05-11

    We present DES13S2cmm, the first spectroscopically-confirmed superluminous supernova (SLSN) from the Dark Energy Survey (DES). We briefly discuss the data and search algorithm used to find this event in the first year of DES operations, and outline the spectroscopic data obtained from the European Southern Observatory (ESO) Very Large Telescope to confirm its redshift (z = 0.663 +/- 0.001 based on the host-galaxy emission lines) and likely spectral type (Type I). Using this redshift, we find M-U(peak) = -21.05(-0.09)(+0.10) for the peak, rest-frame U-band absolute magnitude, and find DES13S2cmm to be located in a faint, low-metallicity (subsolar), low stellar-mass host galaxy (log (M/M-circle dot) = 9.3 +/- 0.3), consistent with what is seen for other SLSNe-I. We compare the bolometric light curve of DES13S2cmm to 14 similarly well-observed SLSNe-I in the literature and find that it possesses one of the slowest declining tails (beyond +30 d rest-frame past peak), and is the faintest at peak. Moreover, we find the bolometric light curves of all SLSNe-I studied herein possess a dispersion of only 0.2-0.3 mag between +25 and +30 d after peak (rest frame) depending on redshift range studied; this could be important for 'standardizing' such supernovae, as is done with the more common Type Ia. We fit the bolometric light curve of DES13S2cmm with two competing models for SLSNe-I-the radioactive decay of Ni-56, and a magnetar - and find that while the magnetar is formally a better fit, neither model provides a compelling match to the data. Although we are unable to conclusively differentiate between these two physical models for this particular SLSN-I, further DES observations of more SLSNe-I should break this degeneracy, especially if the light curves of SLSNe-I can be observed beyond 100 d in the rest frame of the supernova.

  11. Discussions of the Quantum Superluminality%论量子超光速性

    Institute of Scientific and Technical Information of China (English)

    黄志洵

    2012-01-01

    , the experiments proved that Einstein' s ideas didn' t hold water. In Bell' s opinion, to get rid of the difficulties after the announce- ment of the Aspect' s experiments, it intends to go back to Lorentz and Poincare, and assume that ether existed as a referential system in which matters went faster than light. Bell repeatedly pointed out that be wanted to go back to ether because EPR had predicted there was something faster than light in the back- ground. …… Since 1992, it is reported that there have been many successful faster than light experi-ments. Some of them are based on quantum tunneling effect;some are based on classic physical phenome- na such as evanescent waves, anomalous dispersion. And in 2008, D. Salart et. al. performed a experiment using entangled photons between two villages separated by 18km. In conclusion ,the speed of the influence of quantum entanglement would have to exceed than of light by at least four orders of magnitude, i. e. 10^4c 10^7c. Anyway, this experiment was the summation of discussions about the EPR thesis for a long time. For the past 25 years Quantum Superluminality was one subject of my chief study. In 1985 ,we pro- posed the model of quantum potential barrier equivalent circuit. In 1991, we first indicated that there could be the wave velocity vp 〈 0 and vg 〈 0 in the evanescent waves mode of the waveguide below cut off and the book "An Introduction to the Theory of waveguide Below Cut -off " made me get the First Na- tional Scientific and Technology Book Award of China. Moreover, in 2003 we through an experiment in the coaxial photonic crystal, a superluminal group velocity of ( 1.5 - 2.4) c are observed in the stop - band of frequency. In 2005, we suggested the term of General Information Velocity (GIV) ;and in 2010, we sugges- ted the term of Quantum Superluminality ( QS), and also suggested remodel the existing accelerator to dis- cover the superluminal strange electron. Now,this paper discusses some problems of

  12. Monitoring the activity variations of galactic X-ray sources with WATCH on EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, N.

    1995-01-01

    sources the observation periods extended over more than 100 days. A number of X-ray transients with durations between one and five days were discovered, and, additionally two long duration X-ray transients (GRS 1915+10 and GRO J0422+32) were active and could be monitored. Towards the end of the mission...

  13. Speed of the CERN Neutrinos released on 22.9.2011 - Was stated superluminality due to neglecting General Relativity?

    CERN Document Server

    Kundt, Wolfgang

    2011-01-01

    During the years 2009 to 2011, neutrino beams were fired repeatedly from CERN towards a detector in Italy's Gran Sasso tunnel, some 4 deg south and 7 deg east of CERN, at a distance of 730.5 km, in the shape of short bunches of particles. Their time of flight (2.5 msec) was measured at high accuracy (nsec) with caesium clocks (Reich 2011). Remarkably, the CNGS team found a deficit of 61 nsec compared with propagation at the speed of light, and concluded at superluminal speeds, of order 10$^{-4.6}$. In this communication, I will argue that this is the first experiment to test Einstein's theory for the (weak) gravity field of Earth, with the result that the neutrinos propagated (just) luminally.

  14. Do not mess with time: Probing faster than light travel and chronology protection with superluminal warp drives

    CERN Document Server

    Liberati, Stefano

    2016-01-01

    While General Relativity ranks undoubtedly among the best physics theories ever developed, it is also among those with the most striking implications. In particular, General Relativity admits solutions which allow faster than light motion and consequently time travel. Here we shall consider a "pre-emptive" chronology protection mechanism that destabilises superluminal warp drives via quantum matter back-reaction and hence forbids even the conceptual possibility to use these solutions for building a time machine. This result will be considered both in standard quantum field theory in curved spacetime as well as in the case of a quantum field theory with Lorentz invariance breakdown at high energies. Some lessons and future perspectives will be finally discuss.

  15. Neutrino and the Possibility of Superluminal Phenomenon%中微子和超光速现象的可能性

    Institute of Scientific and Technical Information of China (English)

    韩锋

    2012-01-01

    If the rest mass of the neutrino is not zero, it is required that neutrino be superluminal in order to explain the two - component neutrino theory of parity non - conservation. In the light of this, the paper discusses the superluminal phenomenon under the guidance of the theory of relativity and also the possibility of the existence of tachyon.%如果中微子静止质量不为零,那么为了解释宇称不守恒的二分量中微子理论就要求中微子是超光速的。讨论了在相对论框架内对这种超光速现象的理解,以及存在"快子"的可能性。

  16. Is IGR J17091-3624 a Missing Ling between GRS 1915+105 and other Black Hole Low Mass X-ray Binaries?

    CERN Document Server

    Pahari, Mayukh; Bhattacharyya, Sudip

    2011-01-01

    In this work, we study the timing and spectral evolution of the transient low mass X-ray binary IGR J17091-3624 during its recent outburst. We present the results obtained from the observations with two instruments, Rossi X-ray Timing Explorer (RXTE)/ proportional counter array (PCA) and SWIFT/X-ray telescope (XRT), between 03 February 2011 and 10 April 2011. Apart from the detection of X-ray softening within the SWIFT/XRT energy range, we report the details of a transition from a low irregular variability state, commonly seen from most of the black hole X-ray binaries (BHXBs), to a regular, repetitive and large variability state, seen only from GRS 1915+105 ('rho' class variability). Several evidences such as similarities with GRS 1915+105, power-law dominating spectra, finding of type-B and type-C QPOs indicate that central object is a black hole candidate. Using scaling methods under crude approximations, we estimate the upper limit of the mass of the black hole to be 9.13 +/- 2.25 Msun and its distance to...

  17. A low-order coupled chemistry meteorology model for testing online and offline data assimilation schemes: L95-GRS (v1.0)

    Science.gov (United States)

    Haussaire, J.-M.; Bocquet, M.

    2016-01-01

    Bocquet and Sakov (2013) introduced a low-order model based on the coupling of the chaotic Lorenz-95 (L95) model, which simulates winds along a mid-latitude circle, with the transport of a tracer species advected by this zonal wind field. This model, named L95-T, can serve as a playground for testing data assimilation schemes with an online model. Here, the tracer part of the model is extended to a reduced photochemistry module. This coupled chemistry meteorology model (CCMM), the L95-GRS (generic reaction set) model, mimics continental and transcontinental transport and the photochemistry of ozone, volatile organic compounds and nitrogen oxides. Its numerical implementation is described. The model is shown to reproduce the major physical and chemical processes being considered. L95-T and L95-GRS are specifically designed and useful for testing advanced data assimilation schemes, such as the iterative ensemble Kalman smoother (IEnKS), which combines the best of ensemble and variational methods. These models provide useful insights prior to the implementation of data assimilation methods into larger models. We illustrate their use with data assimilation schemes on preliminary yet instructive numerical experiments. In particular, online and offline data assimilation strategies can be conveniently tested and discussed with this low-order CCMM. The impact of observed chemical species concentrations on the wind field estimate can be quantitatively assessed. The impacts of the wind chaotic dynamics and of the chemical species non-chaotic but highly nonlinear dynamics on the data assimilation strategies are illustrated.

  18. A broad spectral feature detected during the cooling phase of a type I X-ray burst from GRS 1747-312 with Suzaku

    Science.gov (United States)

    Iwai, Masachika; Dotani, Tadayasu; Ozaki, Masanobu; Maeda, Yoshitomo; Mori, Hideyuki; Saji, Shigetaka

    2017-08-01

    We analyzed the Suzaku archive data of a type I X-ray burst from GRS 1747-312, a low-mass X-ray binary located in the globular cluster Terzan 6. During the Galactic bulge mapping observations with Suzaku, which covered Terzan 6, an X-ray burst of long duration and with moderate photospheric-radius expansion was serendipitously detected and was considered to be most probably originating from GRS 1747-312. The time-divided burst spectra were reproduced well with an absorbed blackbody over the majority of the time, but significant deviation was detected late in the cooling phase. The deviation was due to a rolled-off feature, which gradually developed in the cooling phase of the burst, in the energy spectra above ∼7 keV. We tested various models to reproduce the spectral feature and found three types of models (reflection by cold matter, partial-covering absorption, and Doppler-smeared absorption edges due to the rapid spin of a neutron star) gave a statistically acceptable fit. We discussed the feasibility of these models, including a non-Planckian nature of the burst spectra.

  19. X-ray Dips Followed by Superluminal Ejections as Evidence for An Accretion Disc Feeding the Jet in A Radio Galaxy

    Science.gov (United States)

    Marscher, Alan P.; Jorstad, Svetlana G.; Gomez, Jose-Luis; Aller, Margo F.; Terasranta, Harri; Lister, Matthew L.; Stirling, Alastair, M.

    2002-01-01

    Accretion onto black holes is thought to power the relativistic jets and other high-energy phenomena in both active galactic nuclei (AGNs) and the "microquasar" binary systems located in our Galaxy. However, until now there has been insufficient multifrequency monitoring to establish a direct observational link between the black hole and the jet in an AGE. This contrasts with the case of microquasars, in which superluminal features appear and propagate down the radio jet shortly after sudden decreases in the X-ray flux. Such an X-ray dip is most likely caused by the disappearance of a section of the inner accretion disc, part of which falls past the event horizon and the remainder of which is injected into the jet. This infusion of energy generates a disturbance that propagates down the jet, creating the appearance of a superluminal bright spot. Here we report the results of three years of intensive monitoring of the X-ray and radio emission of the Seyfert-like radio galaxy 3C 120. As in the case of microquasars, dips in the X-ray emission are followed by ejections of bright superluminal knots in the radio jet. Comparison of the characteristic length and time scales allows us to infer that the rotational states of the black holes in these two objects are different.

  20. Alternating lags of QPO harmonics: A generic model and its application to the 67 mHz QPO of GRS 1915+105

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Ranjeev [Inter-University Center for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune-411007 (India); Mandal, Soma, E-mail: rmisra@iucaa.ernet.in, E-mail: soma@iucaa.ernet.in [Department of Physics, Taki Government College, Taki, North 24 Parganas-743429, West Bengal (India)

    2013-12-10

    A generic model for alternating lags in quasi-periodic oscillation (QPO) harmonics is presented where variations in the photon spectrum are caused by oscillations in two parameters that characterize the spectrum. It is further assumed that variations in one of the parameters are linearly driven by variations in the other after a time delay t{sub d} . It is shown that alternating lags will be observed for a range of t{sub d} values. A phenomenological model based on this generic one is developed that can explain the amplitude and phase lag variation with energy of the fundamental and the next three harmonics of the 67 mHz QPO observed in GRS 1915+105. The phenomenological model also predicts the variation of the Bicoherence phase with energy, which can be checked by further analysis of the observational data.

  1. LSQ14bdq: A Type Ic super-luminous supernova with a double-peaked light curve

    CERN Document Server

    Nicholl, M; Jerkstrand, A; Sim, S A; Inserra, C; Anderson, J P; Baltay, C; Benetti, S; Chambers, K; Chen, T -W; Elias-Rosa, N; Feindt, U; Flewelling, H A; Fraser, M; Gal-Yam, A; Galbany, L; Huber, M E; Kangas, T; Kankare, E; Kotak, R; Krühler, T; Maguire, K; McKinnon, R; Rabinowitz, D; Rostami, S; Schulze, S; Smith, K W; Sullivan, M; Tonry, J L; Valenti, S; Young, D R

    2015-01-01

    We present data for LSQ14bdq, a hydrogen-poor super-luminous supernova (SLSN) discovered by the La Silla QUEST survey and classified by the Public ESO Spectroscopic Survey of Transient Objects. The spectrum and light curve are very similar to slow-declining SLSNe such as PTF12dam. However, detections within $\\sim1$ day after explosion show a bright and relatively fast initial peak, lasting for $\\sim15$ days, prior to the usual slow rise to maximum light. The broader, main peak can be fit with either central engine or circumstellar interaction models. We discuss the implications of the precursor peak in the context of these models. It is too bright and narrow to be explained as a normal \\Ni-powered SN, and we suggest that interaction models may struggle to fit the precursor and main peak simultaneously. We propose that the initial peak is from the post-shock cooling of an extended stellar envelope, and reheating by a central engine drives the second peak. In this picture, we show that an explosion energy of $\\...

  2. Selecting superluminous supernovae in faint galaxies from the first year of the Pan-STARRS1 Medium Deep Survey

    CERN Document Server

    McCrum, M; Rest, A; Smith, K; Kotak, R; Rodney, S A; Young, D R; Chornock, R; Berger, E; Foley, R J; Fraser, M; Wright, D; Scolnic, D; Tonry, J L; Urata, Y; Huang, K; Pastorello, A; Botticella, M T; Valenti, S; Mattila, S; Kankare, E; Farrow, D J; Huber, M E; Stubbs, C W; Kirshner, R P; Bresolin, F; Burgett, W S; Chambers, K C; Draper, P W; Flewelling, H; Jedicke, R; Kaiser, N; Magnier, E A; Metcalfe, N; Morgan, J S; Price, P A; Sweeney, W; Wainscoat, R J; Waters, C

    2014-01-01

    The Pan-STARRS1 (PS1) survey has obtained imaging in 5 bands (grizy_P1) over 10 Medium Deep Survey (MDS) fields covering a total of 70 square degrees. This paper describes the search for apparently hostless supernovae (SNe) within the first year of PS1 MDS data with an aim of discovering new superluminous supernovae (SLSNe). A total of 249 hostless transients were discovered down to a limiting magnitude of M_AB ~ 23.5, of which 75 were classified as Type Ia SNe. There were 58 SNe with complete light curves that are likely core-collapse SNe (CCSNe) or SLSNe and 13 of these have had spectra taken. Of these 13 hostless, non-Type Ia SNe, 9 were SLSNe of Type I at redshifts between 0.5-1.4. Thus one can maximise the discovery rate of Type I SLSNe by concentrating on hostless transients and removing normal SNe Ia. We present data for three new possible SLSNe; PS1-10pm (z = 1.206), PS1-10ahf (z = 1.16) and PS1-11acn (z ~ 0.61), and estimate the rate of SLSNe-I to be between 0.6pm0.3 * 10^-4 and 1.0pm0.3 * 10^-4 of t...

  3. The hydrogen-poor superluminous supernova iPTF13ajg and its host galaxy in absorption and emission

    CERN Document Server

    Vreeswijk, Paul M; Gal-Yam, Avishay; De Cia, Annalisa; Quimby, Robert M; Sullivan, Mark; Cenko, S Bradley; Perley, Daniel A; Filippenko, Alexei V; Clubb, Kelsey I; Taddia, Francesco; Sollerman, Jesper; Leloudas, Giorgos; Arcavi, Iair; Rubin, Adam; Kasliwal, Mansi M; Cao, Yi; Yaron, Ofer; Tal, David; Ofek, Eran O; Capone, John; Kutyrev, Alexander S; Toy, Vicki; Nugent, Peter E; Laher, Russ; Surace, Jason; Kulkarni, Shrinivas R

    2014-01-01

    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory: iPTF13ajg. At a redshift of z=0.7403, derived from narrow absorption lines, iPTF13ajg peaked at an absolute magnitude M(u,AB)=-22.5, one of the most luminous supernovae to date. The uBgRiz light curves, obtained with the P48, P60, NOT, DCT, and Keck telescopes, and the nine-epoch spectral sequence secured with the Keck and the VLT (covering 3 rest-frame months), are tied together photometrically to provide an estimate of the flux evolution as a function of time and wavelength. The observed bolometric peak luminosity of iPTF13ajg is 3.2x10^44 erg/s, while the estimated total radiated energy is 1.3x10^51 erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the VLT. From Voigt-profile fitting, we derive the column densities log N(Mg I)=11.94+-0.06, log ...

  4. PS1-14bj: A Hydrogen-Poor Superluminous Supernova With a Long Rise and Slow Decay

    CERN Document Server

    Lunnan, R; Berger, E; Milisavljevic, D; Jones, D O; Rest, A; Fong, W; Fransson, C; Margutti, R; Drout, M R; Blanchard, P K; Challis, P; Cowperthwaite, P S; Foley, R J; Kirshner, R P; Morell, N; Riess, A G; Roth, K C; Scolnic, D; Smartt, S J; Smith, K W; Villar, V A; Chambers, K C; Draper, P W; Huber, M E; Kaiser, N; Kudritzki, R -P; Magnier, E A; Metcalfe, N; Waters, C

    2016-01-01

    We present photometry and spectroscopy of PS1-14bj, a hydrogen-poor superluminous supernova (SLSN) at redshift $z=0.5215$ discovered in the last months of the Pan-STARRS1 Medium Deep Survey. PS1-14bj stands out by its extremely slow evolution, with an observed rise to maximum light $\\gtrsim 125$ days in the rest frame, and exponential decline out to $\\sim 250$ days past peak at a measured rate of $9.75\\times 10^{-3}$ mag day$^{-1}$, consistent with fully-trapped $^{56}$Co decay. This is the longest rise time measured in a SLSN to date, and the first SLSN to show a rise time consistent with pair-instability supernova (PISN) models. Compared to other slowly-evolving SLSNe, it is spectroscopically similar to the prototype SN 2007bi at maximum light, though somewhat lower in luminosity ($L_{\\rm peak} \\simeq 4.4 \\times 10^{43}~{\\rm erg~s}^{-1}$) and with a flatter peak than previous events. In addition to its slow evolution, PS1-14bj shows a number of peculiar properties, including a near-constant color temperatur...

  5. DES14X3taz: A Type I Superluminous Supernova Showing a Luminous, Rapidly Cooling Initial Pre-Peak Bump

    CERN Document Server

    Smith, M; D'Andrea, C B; Castander, F J; Casas, R; Prajs, S; Papadopoulos, A; Nichol, R C; Karpenka, N V; Bernard, S R; Brown, P; Cartier, R; Cooke, J; Curtin, C; Davis, T M; Finley, D A; Foley, R J; Gal-Yam, A; Goldstein, D A; González-Gaitán, S; Gupta, R R; Howell, D A; Inserra, C; Kessler, R; Lidman, C; Marriner, J; Nugent, P; Pritchard, T A; Sako, M; Smartt, S; Smith, R C; Spinka, H; Wolf, R C; Zentano, A; Abbott, T M C; Benoit-Lévy, A; Brooks, D; Buckley-Geer, E; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Crocce, M; Cunha, C E; da Costa, L N; Desai, S; Diehl, H T; Doel, P; Estrada, J; Evrard, A E; Flaugher, B; Fosalba, P; Frieman, J; Gerdes, D W; Gruen, D; Gruendl, R A; James, D J; Kuehn, K; Kuropatkin, N; Lahav, O; Li, T S; Marshall, J L; Martini, P; Miller, C J; Miquel, R; Ogando, R; Plazas, A A; Romer, A K; Roodman, A; Rykoff, E S; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla-Noarbe, I; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thomas, R C; Walker, A R; Wester, W

    2015-01-01

    We present DES14X3taz, a new hydrogen-poor super luminous supernova (SLSN-I) discovered by the Dark Energy Survey (DES) supernova program, with additional photometric data provided by the Survey Using DECam for Superluminous Supernovae (SUDSS). Spectra obtained using OSIRIS on the Gran Telescopio CANARIAS (GTC) show DES14X3taz is a SLSN-I at z=0.608. Multi-color photometry reveals a double-peaked light curve: a blue and relatively bright initial peak that fades rapidly prior to the slower rise of the main light curve. Our multi-color photometry allows us, for the first time, to show that the initial peak cools from 22,000K to 8,000K over 15 rest-frame days, and is faster and brighter than any published core-collapse supernova, reaching 30% of the bolometric luminosity of the main peak. No physical Ni-powered model can fit this initial peak. We show that a shock-cooling model followed by a magnetar driving the second phase of the light curve can adequately explain the light curve of DES14X3taz, with the coolin...

  6. Far-Ultraviolet to Near-Infrared Spectroscopy of A Nearby Hydrogen Poor Superluminous Supernova Gaia16apd

    CERN Document Server

    Yan, Lin; Gal-Yam, A; Brown, P; Blagorodnova, N; Ofek, E O; Lunnan, R; Cooke, J; Cenko, S B; Jencson, J; Kasliwal, M

    2016-01-01

    We report the first maximum-light far-Ultraviolet to near-infrared spectra (1000A - 1.62um, rest) of a H-poor superluminous supernova, Gaia16apd. At z=0.1018, it is one of the closest and the UV brightest such events, with 17.4 (AB) magnitude in Swift UV band (1928A) at -11days pre-maximum. Assuming an exponential form, we derived the rise time of 33days and the peak bolometric luminosity of 3x10^{44}ergs^-1. At maximum light, the estimated photospheric temperature and velocity are 17,000K and 14,000kms^-1 respectively. The inferred radiative and kinetic energy are roughly 1x10^{51} and 2x10^{52}erg. Gaia16apd is extremely UV luminous, emitting 50% of its total luminosity at 1000 - 2500A. Compared to the UV spectra (normalized at 3100A) of well studied SN1992A (Ia), SN2011fe(Ia), SN1999em (IIP) and SN1993J (IIb), it has orders of magnitude more far-UV emission. This excess is interpreted primarily as a result of weaker metal line blanketing due to much lower abundance of iron-group elements in the outer eject...

  7. Environmental fifth-force hypothesis for the OPERA superluminal neutrino phenomenology: constraints from orbital motions around the Earth

    CERN Document Server

    Iorio, Lorenzo

    2011-01-01

    It has been recently suggested by Dvali and Vikman [arXiv:1109.5685] that the superluminal neutrino phenomenology of the OPERA experiment may be due to an environmental feature of the Earth, naturally yielding a long-range fifth force of gravitational origin. Its scale length l should not be smaller than one Earth's radius Re, while its upper bound is expected to be slightly smaller than the Earth-Moon distance (60 Re). We analytically work out some orbital effects of a Yukawa-type fifth force for a test particle moving in the modified field of a central body. Our results are quite general since they are not restricted to any particular size of l; moreover, they are valid for an arbitrary orbital configuration of the particle, i.e. for any value of its eccentricity e. We find that the dimensionless strength coupling parameter a is constrained to |a| <= 5\\times10-10 for 1 Re <= l <= 4 Re by the laser data of the Earth's artificial satellite LAGEOS II. The Moon perigee allows to obtain |a| <= 3\\time...

  8. Hole-burning in an Autler-Townes doublet and in superluminal (subluminal) Electromagnetically induced transparency of a light pulse via a joint nonlinear coherent Kerr effect and Doppler broadening

    CERN Document Server

    Bacha, Bakhtt A; Ahmad, Iftikhar

    2013-01-01

    We investigate the behavior of light pulse propagation in a 4-level double Lambda atomic system under condition of electromagnetically induced transparency. The Fano type interference effect and spectral hole burning appears in the the dynamics of the absorption-dispersion spectra caused by the joint nonlinear coherence Kerr effect and Doppler broadening. The coherent Kerr effect exhibits an enhancement (reduction) in superluminal (subluminal) in negative (in positive) group index while the Doppler broadening generates multiple hole burning in the Autler-Townes like spectra of this system. The hole burning in addition with coherent Kerr effect on the spectral profile influences the dynamics of subluminal and superluminal of the probe pulse through the medium. The characteristics of superluminality and subluminality modified by considering cold-Kerr-free medium and hot-Kerr-dependent mediums. The light pulse delays and advances in different regions of dispersion medium with the Doppler broadening and coherent ...

  9. GRS knowledge base ''Safety of pressure-bearing components'' - An example of knowledge management of a technical support organisation; GRS-Wissensbasis ''Sicherheit druckfuehrender Komponenten'' - Ein Beispiel zum Wissensmanagement einer Sachverstaendigenorganisation

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, H.; Michel, F. [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koeln (Germany)

    2005-07-01

    In long-lived technical systems, the main challenge is in preserving knowledge on all technical aspects throughout the plant life as several generations of engineers are involved from projecting to decommissioning. A technical support organisation has access to knowledge on safety requirements and their development with time, relevant damage cases both in Germany and abroad, research projects and analyses as well as expert documentations. A modern working environment enables fast access to, and combination of, distributed parts of knowledge provided that some prestructuring is ensured. The contribution presents an exemplary information system of GRS, whose elements may be of interest to other organisations as well. [German] Fuer technische Anlagen mit langen Lebenszeiten ist es eine besondere Herausforderung, das erforderliche Wissen zu allen technischen Sachverhalten jederzeit verfuegbar zu haben. Von der Projektierung bis zum Betriebsende einer Anlage sind mehrere Generationen von Ingenieuren mit den jeweiligen Sachverhalten befasst. Fuer eine Sachverstaendigenorganisation stehen Kenntnisse zu den sicherheitstechnischen Anforderungen und deren zeitlicher Entwicklung, relevanten Schadensereignissen im In- und Ausland, Erkenntnisse aus Forschungsvorhaben und Analysen sowie die Verfuegbarkeit des weiteren dokumentierten Fachwissens und technischer Experten im Vordergrund. Die moderne Arbeitsumgebung erlaubt heute ein schnelles Auffinden und Zusammenfuehren der vorhandenen Wissensbausteine. Eine sinnvolle Vorstrukturierung als Wegweiser im Dschungel der Informationen ist jedoch unerlaesslich. Ein auf die Beduerfnisse der GRS zugeschnittenes Beispiel wird im Einzelnen vorgestellt. Wesentliche Elemente der Struktur fuer ein praktikables Wissensmanagement sind auch fuer andere Organisationen nutzbar.

  10. Two parameters describing a superluminal neutrino%二参量描述的超光速中微子述的超光速中微子

    Institute of Scientific and Technical Information of China (English)

    倪光炯; 张操

    2002-01-01

    Based on the experimental data that the mass-square of neutrino might be negative, a quantum theory for superluminal neutrino is proposed. Two Weyl equations coupled together via a mass term respecting the maximum parity violation lead to a new equation which describes the superluminal motion of neutrino with permanent helicity. Various strange features of subluminal and superluminal particles can be ascribed to the relative variation of two contradictory fields superposing coherently inside the particle with the change of its speed u in the whole range (0<u<∞). Being compatible with the theory of special relativity, this theory may have various applications.%根据中微子质量平方是负值的实验数据,提出了一个关于超光速中微子的量子理论.用一个和最大宇称破坏相关的质量项将两个Weyl方程耦合在一起,得到一个描述具有永久螺旋度且超光速运动的中微子的新方程.超光速粒子的速度在 (0,∞)范围内变化,其内部相干迭加的两个矛盾场的相对变化导致亚光速粒子和超光速粒子的各种奇异特性.这个理论和狭义相对论是兼容的,因而可以有多方面的应用.

  11. PS1-10bzj: A FAST, HYDROGEN-POOR SUPERLUMINOUS SUPERNOVA IN A METAL-POOR HOST GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Lunnan, R.; Chornock, R.; Berger, E.; Milisavljevic, D.; Drout, M.; Sanders, N. E.; Challis, P. M.; Czekala, I.; Foley, R. J.; Fong, W.; Kirshner, R. P.; Leibler, C.; Marion, G. H.; Narayan, G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Huber, M. E. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); McCrum, M.; Smartt, S. J. [Astrophysics Research Centre, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Rest, A. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Roth, K. C. [Gemini Observatory, 670 N. Aohoku Place, Hilo, HI 96720 (United States); Scolnic, D., E-mail: rlunnan@cfa.harvard.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); and others

    2013-07-10

    We present observations and analysis of PS1-10bzj, a superluminous supernova (SLSN) discovered in the Pan-STARRS Medium Deep Survey at a redshift z = 0.650. Spectroscopically, PS1-10bzj is similar to the hydrogen-poor SLSNe 2005ap and SCP 06F6, though with a steeper rise and lower peak luminosity (M{sub bol} {approx_equal} -21.4 mag) than previous events. We construct a bolometric light curve, and show that while PS1-10bzj's energetics were less extreme than previous events, its luminosity still cannot be explained by radioactive nickel decay alone. We explore both a magnetar spin-down and circumstellar interaction scenario and find that either can fit the data. PS1-10bzj is located in the Extended Chandra Deep Field South and the host galaxy is imaged in a number of surveys, including with the Hubble Space Telescope. The host is a compact dwarf galaxy (M{sub B} Almost-Equal-To -18 mag, diameter {approx}< 800 pc), with a low stellar mass (M{sub *} Almost-Equal-To 2.4 Multiplication-Sign 10{sup 7} M{sub Sun }), young stellar population ({tau}{sub *} Almost-Equal-To 5 Myr), and a star formation rate of {approx}2-3 M{sub Sun} yr{sup -1}. The specific star formation rate is the highest seen in an SLSN host so far ({approx}100 Gyr{sup -1}). We detect the [O III] {lambda}4363 line, and find a low metallicity: 12 + (O/H) = 7.8 {+-} 0.2 ({approx_equal} 0.1 Z{sub Sun }). Together, this indicates that at least some of the progenitors of SLSNe come from young, low-metallicity populations.

  12. Taking stock of superluminous supernovae and long gamma-ray burst host galaxy comparison using a complete sample of LGRBs

    Science.gov (United States)

    Japelj, J.; Vergani, S. D.; Salvaterra, R.; Hunt, L. K.; Mannucci, F.

    2016-10-01

    Long gamma-ray bursts (LGRBs) and superluminous supernovae (SLSNe) are both explosive transients with very massive progenitor stars. Clues about the nature of the progenitors can be found by investigating environments in which such transients occur. While studies of LGRB host galaxies have a long history, dedicated observational campaigns have only recently resulted in a high enough number of photometrically and spectroscopically observed SLSN hosts to allow statistically significant analysis of their properties. In this paper we make a comparison of the host galaxies of hydrogen-poor (H-poor) SLSNe and the Swift/BAT6 sample of LGRBs. In contrast to previous studies, we use a complete sample of LGRBs and we pay special attention to the comparison methodology and the selection of SLSN sample whose data have been compiled from the available literature. At intermediate redshifts (0.3 < z < 0.7) the two classes of transients select galaxies whose properties (stellar mass, luminosity, star formation rate, specific star formation rate and metallicity) do not differ significantly. Moreover, the host galaxies of both classes of objects follow the fundamental metallicity relation and the fundamental plane of metallicity. In contrast to previous studies we show that at intermediate redshifts the emission line equivalent widths of the two populations are essentially the same and that the previous claims regarding the higher fraction of SLSN hosts among the extreme emission line galaxies with respect to LGRBs are mostly due to a larger fraction of strong-line emitters among SLSN hosts at z < 0.3, where samples of LGRB hosts are small and poorly defined.

  13. Hydrogen-poor superluminous supernovae and long-duration gamma-ray bursts have similar host galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Lunnan, R.; Chornock, R.; Berger, E.; Laskar, T.; Fong, W.; Sanders, N. E.; Challis, P. M.; Drout, M. R.; Foley, R. J.; Kirshner, R. P.; Leibler, C.; Marion, G. H.; Milisavljevic, D.; Narayan, G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Huber, M. E. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); McCrum, M.; Smartt, S. J.; Smith, K. W. [Astrophysics Research Centre, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Scolnic, D., E-mail: rlunnan@cfa.harvard.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); and others

    2014-06-01

    We present optical spectroscopy and optical/near-IR photometry of 31 host galaxies of hydrogen-poor superluminous supernovae (SLSNe), including 15 events from the Pan-STARRS1 Medium Deep Survey. Our sample spans the redshift range 0.1 ≲ z ≲ 1.6, and is the first comprehensive host galaxy study of this specific subclass of cosmic explosions. Combining the multi-band photometry and emission-line measurements, we determine the luminosities, stellar masses, star formation rates, and metallicities. We find that, as a whole, the hosts of SLSNe are a low-luminosity ((M{sub B} ) ≈ –17.3 mag), low stellar mass ((M {sub *}) ≈ 2 × 10{sup 8} M {sub ☉}) population, with a high median specific star formation rate ((sSFR) ≈ 2 Gyr{sup –1}). The median metallicity of our spectroscopic sample is low, 12 + log (O/H) ≈ 8.35 ≈ 0.45 Z {sub ☉}, although at least one host galaxy has solar metallicity. The host galaxies of H-poor SLSNe are statistically distinct from the hosts of GOODS core-collapse SNe (which cover a similar redshift range), but resemble the host galaxies of long-duration gamma-ray bursts (LGRBs) in terms of stellar mass, SFR, sSFR, and metallicity. This result indicates that the environmental causes leading to massive stars forming either SLSNe or LGRBs are similar, and in particular that SLSNe are more effectively formed in low metallicity environments. We speculate that the key ingredient is large core angular momentum, leading to a rapidly spinning magnetar in SLSNe and an accreting black hole in LGRBs.

  14. Characterizing a new class of variability in GRS 1915+105 with simultaneous INTEGRAL/RXTE observations

    DEFF Research Database (Denmark)

    Hannikainen, D.C.; Rodriguez, J.; Vilhu, O.

    2005-01-01

    , 271) but not to any previously known variability class. We separated the INTEGRAL data into two subsets covering the maxima and minima of the pulses and fitted the resulting two broadband spectra with a hybrid thermal-non-thermal Comptonization model. The fits show the source to be in a soft state...... characterized by a strong disc component below &SIM; 6 keV and Comptonization by both thermal and non-thermal electrons at higher energies....

  15. A model for the energy-dependent time-lag and rms of the heartbeat oscillations in GRS 1915+105

    CERN Document Server

    Mir, Mubashir Hamid; Pahari, Mayukh; Iqbal, Naseer; Ahmad, Naveel

    2016-01-01

    Energy dependent phase lags reveal crucial information about the causal relation between various spectral components and about the nature of the accretion geometry around the compact objects. The time-lag and the fractional root mean square (rms) spectra of GRS 1915+105 in its heartbeat oscillation class/$\\rho$ state show peculiar behaviour at the fundamental and harmonic frequencies where the lags at the fundamental show a turn around at $\\sim$ 10 keV while the lags at the harmonic do not show any turn around at least till $\\sim$ 20 keV. The magnitude of lags are of the order of few seconds and hence cannot be attributed to the light travel time effects or Comptonization delays. The continuum X-ray spectra can roughly be described by a disk blackbody and a hard X-ray power-law component and from phase resolved spectroscopy it has been shown that the inner disk radius varies during the oscillation. Here, we propose that there is a delayed response of the inner disk radius (DROID) to the accretion rate such th...

  16. Temporal study of GRS 1915+105 with rms-flux relation:The importance of magnetic activities in the corona

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The rms-flux relations for some observations of GRS 1915+105 are studied.The rms-flux relations of the light curves in only one state,state C or state A,can be described by the simple non-linear model provided Zhang;we thus interpret that such a linear relation reflects the relative importance of magnetic instability for X-ray emission in the corona of the system,compared to the thermal viscous instability for the X-ray emission in the accretion disk.The rms-flux relations for state B are very scattered,possibly because of the dominance of thermal viscous instability for the X-ray emission in the accretion disk.The complex rms-flux relations for the observations of transitions between two or three states are caused by the combination of the different rms-flux relations of these states.The underlying physical processes are the combination of magnetic topology in the corona and thermal viscous instability in the accretion disk.

  17. The Unusual Super-luminous Supernovae SN 2011kl and ASASSN-15lh

    Science.gov (United States)

    Bersten, Melina C.; Benvenuto, Omar G.; Orellana, Mariana; Nomoto, Ken'ichi

    2016-01-01

    Two recently discovered very luminous supernovae (SNe) present stimulating cases to explore the extents of the available theoretical models. SN 2011kl represents the first detection of a supernova explosion associated with an ultra-long duration gamma-ray burst. ASASSN-15lh was even claimed as the most luminous SN ever discovered, challenging the scenarios so far proposed for stellar explosions. Here we use our radiation hydrodynamics code in order to simulate magnetar-powered SNe. To avoid explicitly assuming neutron star properties, we adopt the magnetar luminosity and spin-down timescale as free parameters of the model. We find that the light curve (LC) of SN 2011kl is consistent with a magnetar power source, as previously proposed, but we note that some amount of 56Ni (≳ 0.08{M}⊙ ) is necessary to explain the low contrast between the LC peak and tail. For the case of ASASSN-15lh, we find physically plausible magnetar parameters that reproduce the overall shape of the LC provided the progenitor mass is relatively large (an ejecta mass of ≈ 6{M}⊙ ). The ejecta hydrodynamics of this event is dominated by the magnetar input, while the effect is more moderate for SN 2011kl. We conclude that a magnetar model may be used for the interpretation of these events and that the hydrodynamical modeling is necessary to derive the properties of powerful magnetars and their progenitors.

  18. The Unusual Super-Luminous Supernovae SN 2011kl and ASASSN-15lh

    CERN Document Server

    Bersten, Melina C; Orellana, Mariana; Nomoto, Ken'ichi

    2016-01-01

    Two recently discovered very luminous supernovae (SNe) present stimulating cases to explore the extents of the available theoretical models. SN 2011kl represents the first detection of a supernova explosion associated with an ultra-long duration gamma ray burst. ASASSN-15lh was even claimed as the most luminous SN ever discovered, challenging the scenarios so far proposed for stellar explosions. Here we use our radiation hydrodynamics code in order to simulate magnetar powered SNe. To avoid explicitly assuming neutron star properties we adopt the magnetar luminosity and spin-down timescale as free parameters of the model. We find that the light curve (LC) of SN 2011kl is consistent with a magnetar power source, as previously proposed, but we note that some amount of 56^Ni (> 0.08 M_sun) is necessary to explain the low contrast between the LC peak and tail. For the case of ASASSN-15lh we find physically plausible magnetar parameters that reproduce the overall shape of the LC provided the progenitor mass is rel...

  19. DETECTION OF BROAD Hα EMISSION LINES IN THE LATE-TIME SPECTRA OF A HYDROGEN-POOR SUPERLUMINOUS SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Lin; Masci, F. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Quimby, R. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Ofek, E.; Gal-Yam, A.; Vreeswijk, P. M.; Leloudas, G.; Cia, A. de; Yaron, O. [Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Mazzali, P. [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Perley, D. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Cao, Y.; Kulkarni, S. R. [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Nugent, P. E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rebbapragada, Umaa D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Woźniak, P. R., E-mail: lyan@ipac.caltech.edu [Space and Remote Sensing, ISR-2, MS-B244 Los Alamos National Laboratory Los Alamos, NM 87545 (United States)

    2015-12-01

    iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83–148 days to reach a peak bolometric luminosity of ∼1.3 × 10{sup 44} erg s{sup −1}, then decays slowly at 0.015 mag day{sup −1}. The measured ejecta velocity is ∼ 13,000 km s{sup −1}. The inferred explosion characteristics, such as the ejecta mass (70–220 M{sub ⊙}), and the total radiative and kinetic energy (E{sub rad} ∼ 10{sup 51} erg, E{sub kin} ∼ 2 × 10{sup 53} erg), are typical of slow-evolving H-poor SLSN events. However, the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ∼4500 km s{sup −1} and a ∼300 km s{sup −1} blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ∼2 × 10{sup 41} erg s{sup −1} as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ∼4 × 10{sup 16} cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M{sub ⊙}. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M{sub ⊙} H-shell, ejected from a progenitor star with an initial mass of (95–150) M{sub ⊙} about 40 years ago. We estimate that at least ∼15% of all SLSNe-I may have late-time Balmer emission lines.

  20. The hydrogen-poor superluminous supernova iPTF 13ajg and its host galaxy in absorption and emission

    Energy Technology Data Exchange (ETDEWEB)

    Vreeswijk, Paul M.; Gal-Yam, Avishay; De Cia, Annalisa; Rubin, Adam; Yaron, Ofer; Tal, David; Ofek, Eran O. [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001 (Israel); Savaglio, Sandra [Max Planck Institute for Extraterrestrial Physics, D-85748 Garching bei München (Germany); Quimby, Robert M. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8583 (Japan); Sullivan, Mark [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Cenko, S. Bradley; Filippenko, Alexei V.; Clubb, Kelsey I. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Perley, Daniel A.; Cao, Yi [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Taddia, Francesco; Sollerman, Jesper; Leloudas, Giorgos [Department of Astronomy, The Oskar Klein Center, Stockholm University, AlbaNova 10691 Stockholm (Sweden); Arcavi, Iair [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Kasliwal, Mansi M., E-mail: paul.vreeswijk@weizmann.ac.il [The Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); and others

    2014-12-10

    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory, iPTF 13ajg. At a redshift of z = 0.7403, derived from narrow absorption lines, iPTF 13ajg peaked at an absolute magnitude of M {sub u,} {sub AB} = –22.5, one of the most luminous supernovae to date. The observed bolometric peak luminosity of iPTF 13ajg is 3.2 × 10{sup 44} erg s{sup –1}, while the estimated total radiated energy is 1.3 × 10{sup 51} erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the Very Large Telescope. From Voigt profile fitting, we derive the column densities log N(Mg I) =11.94 ± 0.06, log N(Mg II) =14.7 ± 0.3, and log N(Fe II) =14.25 ± 0.10. These column densities, as well as the Mg I and Mg II equivalent widths of a sample of hydrogen-poor SLSNe taken from the literature, are at the low end of those derived for gamma-ray bursts (GRBs) whose progenitors are also thought to be massive stars. This suggests that the environments of hydrogen-poor SLSNe and GRBs are different. From the nondetection of Fe II fine-structure absorption lines, we derive a lower limit on the distance between the supernova and the narrow-line absorbing gas of 50 pc. The neutral gas responsible for the absorption in iPTF 13ajg exhibits a single narrow component with a low velocity width, ΔV = 76 km s{sup –1}, indicating a low-mass host galaxy. No host galaxy emission lines are detected, leading to an upper limit on the unobscured star formation rate (SFR) of SFR{sub [O} {sub II]}<0.07M{sub ⊙}yr{sup −1}. Late-time imaging shows the iPTF 13ajg host galaxy to be faint, with g {sub AB} ≈ 27.0 and R {sub AB} ≥ 26.0 mag, corresponding to M {sub B,} {sub Vega} ≳ –17.7 mag.

  1. 基于聚类NASVD的CE2-GRS月表放射性元素Th计数率分布%Distribution of the Thorium Counting Rate on the Lunar Surface from CE2-GRS Based on Cluster NASVD

    Institute of Scientific and Technical Information of China (English)

    李晓丽; 葛良全; 杨佳; 熊盛青

    2015-01-01

    月表Th元素分布特征对于分析月表岩石成因及化学特征等提供了重要依据。为了减小嫦娥二号伽玛谱(CE2-GRS)噪声对获取Th元素分布特征的影响,提出了一种基于噪声调整的奇异值分解(NASVD)去噪算法。通过伽玛谱预处理、去噪、本底扣除及净峰面积求解等步骤,获得月表放射性元素Th计数率全月分布图。通过与国内外其他方法所获得的Th元素计数率分布图对比有较高的一致性。与传统伽玛谱去噪算法比较,聚类NASVD算法能有效地去除统计涨落噪声影响,提取出嫦娥二号伽玛谱中的特征峰信息。%The distribution of thorium on the lunar surface provides the important evidence for lunar evolution history. It is difficult to obtain the distribution of thorium on the lunar surface from CE2-GRS because of noise in the spectrum. The method for smoothing the spectrum is proposed which is based on cluster NASVD. The counting rate map of thorium on the lunar surface is achieved from CE2-GRS. Counting rate map of thorium gamma-rays shows a surface thorium distribution that is in general agreement with other measurement from LP-GRS and SLENE GRS which have better accuracy. It is more effectively to reduce the noise and get the weak information of characteristic peak used the method of cluster NASVD than other traditional methods for smoothing gamma-ray spectrum.

  2. INVESTIGATING THE CONNECTION BETWEEN QUASI-PERIODIC OSCILLATIONS AND SPECTRAL COMPONENTS WITH NuSTAR DATA OF GRS 1915+105

    Energy Technology Data Exchange (ETDEWEB)

    Jassal, Anjali Rao; Vadawale, Santosh V.; Mithun, N. P. S. [Physical Research Laboratory, Ahmedabad-380009 (India); Misra, Ranjeev, E-mail: anjali@prl.res.in [Inter-University Center for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India)

    2016-01-20

    Low-frequency quasi-periodic oscillations (QPOs) are commonly observed during the hard states of black hole binaries. Several studies have established various observational/empirical correlations between spectral parameters and QPO properties, indicating a close link between the two. However, the exact mechanism of generation of QPOs is not yet well understood. In this paper, we present our attempts to comprehend the connection between the spectral components and the low-frequency QPO (LFQPO) observed in GRS 1915+105 using the data from NuSTAR. Detailed spectral modeling as well as the presence of the LFQPO and its energy dependence during this observation have been reported by Miller et al. and Zhang et al., respectively. We investigate the compatibility of the spectral model and the energy dependence of the QPO by simulating light curves in various energy bands for small variation of the spectral parameters. The basic concept here is to establish the connection, if any, between the QPO and the variation of either a spectral component or a specific parameter, which in turn can shed some light on the origin of the QPO. We begin with the best-fit spectral model of Miller et al. and simulate the light curve by varying the spectral parameters at frequencies close to the observed QPO frequency in order to generate the simulated QPO. Furthermore we simulate similar light curves in various energy bands in order to reproduce the observed energy dependence of the rms amplitude of the QPO. We find that the observed trend of increasing rms amplitude with energy can be reproduced qualitatively if the spectral index is assumed to be varying with the phases of the QPO. Variation of any other spectral parameter does not reproduce the observed energy dependence.

  3. Superluminal advanced transmission of X waves undergoing frustrated total internal reflection: the evanescent fields and the Goos-Hänchen effect.

    Science.gov (United States)

    Shaarawi, Amr M; Tawfik, Bassem H; Besieris, Ioannis M

    2002-10-01

    A study of X waves undergoing frustrated total internal reflection at a planar slab is provided. This is achieved by choosing the spectral plane wave components of the incident X wave to fall on the upper interface at angles greater than the critical angle. Thus, evanescent fields are generated in the slab and the peak of the field tunneling through the slab appears to be transmitted at a superluminal speed. Furthermore, it is shown that for deep barrier penetration, the peak of the transmitted field emerges from the rear interface of the slab before the incident peak reaches the front interface. To understand this advanced transmission of the peak of the pulse, a detailed study of the behavior of the evanescent fields in the barrier region is undertaken. The difference in tunneling behavior between deep and shallow barrier penetrations is shown to be influenced by the sense of the Goos-Hänchen shift.

  4. The superluminal neutrino hypothesis

    CERN Document Server

    Ehrlich, Robert

    2012-01-01

    This paper summarizes five observations suggesting that one of the neutrinos is consistent with being a tachyon. The five observations include: (1) Experiments measuring the neutrino speed, (2) Mass eigenstates claimed for SN 1987A neutrinos, (3) ${m}^2$ values of flavor eigenstates, (4) The shape of the high energy cosmic ray spectrum, and (5) Neutral hadrons in the cosmic rays from Cygnus X-3.

  5. Superluminous Spiral Galaxies

    CERN Document Server

    Ogle, Patrick M; Nader, Cyril; Helou, George

    2015-01-01

    We report the discovery of spiral galaxies that are as optically luminous as elliptical brightest cluster galaxies, with r-band monochromatic luminosity L_r=8-14L* (4.3-7.5E44 erg/s). These super spiral galaxies are also giant and massive, with diameter D=57-134 kpc and stellar mass M_stars=0.3-3.4E11 M_sun. We find 53 super spirals out of a complete sample of 1,616 SDSS galaxies with redshift z8L*. The closest example is found at z=0.089. We use existing photometry to estimate their stellar masses and star formation rates (SFRs). The SDSS and WISE colors are consistent with normal star-forming spirals on the blue sequence. However, the extreme masses and rapid SFRs of 5-65 M_sun/yr place super spirals in a sparsely populated region of parameter space, above the star-forming main sequence of disk galaxies. Super spirals occupy a diverse range of environments, from isolation to cluster centers. We find four super spiral galaxy systems that are late-stage major mergers--a possible clue to their formation. We su...

  6. SUPERLUMINOUS SPIRAL GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Ogle, Patrick M.; Lanz, Lauranne; Nader, Cyril; Helou, George, E-mail: ogle@ipac.caltech.edu [IPAC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States)

    2016-02-01

    We report the discovery of spiral galaxies that are as optically luminous as elliptical brightest cluster galaxies, with r-band monochromatic luminosity L{sub r} = 8–14L* (4.3–7.5 × 10{sup 44} erg s{sup −1}). These super spiral galaxies are also giant and massive, with diameter D = 57–134 kpc and stellar mass M{sub stars} = 0.3–3.4 × 10{sup 11}M{sub ⊙}. We find 53 super spirals out of a complete sample of 1616 SDSS galaxies with redshift z < 0.3 and L{sub r} > 8L*. The closest example is found at z = 0.089. We use existing photometry to estimate their stellar masses and star formation rates (SFRs). The SDSS and Wide-field Infrared Survey Explorer colors are consistent with normal star-forming spirals on the blue sequence. However, the extreme masses and rapid SFRs of 5–65 M{sub ⊙} yr{sup −1} place super spirals in a sparsely populated region of parameter space, above the star-forming main sequence of disk galaxies. Super spirals occupy a diverse range of environments, from isolation to cluster centers. We find four super spiral galaxy systems that are late-stage major mergers—a possible clue to their formation. We suggest that super spirals are a remnant population of unquenched, massive disk galaxies. They may eventually become massive lenticular galaxies after they are cut off from their gas supply and their disks fade.

  7. Progress report within the series of GRS-F progress reports on reactor safety, sponsored by the Federal Ministry of Economics and Labour. Period: 1 July - 31 December 2003; Berichte ueber vom Bundesministerium fuer Wirtschaft und Arbeit gefoerderte Forschungsvorhaben auf dem Gebiet der Reaktorsicherheit. Berichtszeitraum: 01. Juli - 31. Dezember 2003

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, by order of the BMWi, continuously issues information on the status of the investigations into the safety of nuclear power plants by publishing semi-annual and annual progress reports within the series of GRS-F-Fortschrittsberichte (GRS-F-Progress Reports). Each progress report represents a compilation of individual reports about the objectives, work performed, results achieved, next steps of the work etc. The individual reports are prepared in a standard form by the research organisations themselves as documentation of their progress in work and are published by the Research Management Division of GRS within the framework of general information on the progress in reactor safety research. The compilation of the reports is classified according to general topics related to reactor safety research. Further, use is made of the classification system ''Joint Safety Research Index'' of the CEC (commission of the european communities). The reports are arranged in sequence of their project numbers. (orig.) [German] Die Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH informiert im Auftrag des BMWi halbjaehrlich und jaehrlich ueber den Stand der Untersuchungen zur Sicherheit von Kernreaktoren in den Fortschrittsberichten der GRS-F-Berichtsreihe. Jeder Fortschrittsbericht stellt eine Sammlung von Einzelberichten ueber Zielsetzung, durchgefuehrte Arbeiten, erzielte Ergebnisse, geplante Weiterarbeit etc. dar, die von den Forschungsstellen selbst als Dokumentation ihres Arbeitsfortschritts in einheitlicher Form erstellt und von der Forschungsbetreuung (FB) in der GRS im Rahmen der allgemeinen Information ueber die Fortschritte von Untersuchungen zur Reaktorsicherheit herausgegeben werden. Die inhaltliche Gliederung der Berichtssammlung erfolgt durch sachliche Zuordnung der Vorhaben zu uebergeordneten Themenbereichen der Reaktorsicherheitsforschung, ferner nach dem Klassifikationsschema

  8. The multidrug resistance 1 (MDR1 gene polymorphism G-rs3789243-A is not associated with disease susceptibility in Norwegian patients with colorectal adenoma and colorectal cancer; a case control study

    Directory of Open Access Journals (Sweden)

    Hamfjord Julian

    2009-02-01

    Full Text Available Abstract Background Smoking, dietary factors, and alcohol consumption are known life style factors contributing to gastrointestinal carcinogenesis. Genetic variations in carcinogen handling may affect cancer risk. The multidrug resistance 1(MDR1/ABCB1 gene encodes the transport protein P-glycoprotein (a phase III xenobiotic transporter. P-glycoprotein is present in the intestinal mucosal lining and restricts absorption of certain carcinogens, among these polycyclic aromatic hydrocarbons. Moreover, P-glycoprotein transports various endogenous substrates such as cytokines and chemokines involved in inflammation, and may thereby affect the risk of malignity. Hence, genetic variations that modify the function of P-glycoprotein may be associated with the risk of colorectal cancer (CRC. We have previously found an association between the MDR1 intron 3 G-rs3789243-A polymorphism and the risk of CRC in a Danish study population. The aim of this study was to investigate if this MDR1 polymorphism was associated with risk of colorectal adenoma (CA and CRC in the Norwegian population. Methods Using a case-control design, the association between the MDR1 intron 3 G-rs3789243-A polymorphism and the risk of colorectal carcinomas and adenomas in the Norwegian population was assessed in 167 carcinomas, 990 adenomas, and 400 controls. Genotypes were determined by allelic discrimination. Odds ratio (OR and 95 confidence interval (95% CI were estimated by binary logistic regression. Results No association was found between the MDR1 polymorphism (G-rs3789243-A and colorectal adenomas or cancer. Carriers of the variant allele of MDR1 intron 3 had odds ratios (95% CI of 0.97 (0.72–1.29 for developing adenomas, and 0.70 (0.41–1.21 for colorectal cancer, respectively, compared to homozygous wild type carriers. Conclusion The MDR1 intron 3 (G-rs3789243-A polymorphism was not associated with a risk of colorectal adenomas or carcinomas in the present Norwegian study

  9. 3C380: a powerful radio source seen end-on

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, P.N. (Nuffield Radio Astronomy Labs., Jodrell Bank (UK)); Akujor, C.E. (Nuffield Radio Astronomy Labs., Jodrell Bank (UK) Nigeria Univ., Nsukka (Nigeria). Dept of Physics); Cornwell, T.J. (National Radio Astronomy Observatory, Socorro, N.M. (USA)); Saikia, D.J. (Nuffield Radio Astronomy Labs., Jodrell Bank (UK) Tata Inst. of Fundamental Research, GMRT Project, Pune (India))

    1991-01-01

    We present new VLA, MERLIN and VLBI observations of 3C380, a powerful compact steep-spectrum radio source with complex extended structure, and attempt to clarify whether it is a larger source seen end-on or whether is is intrinsically of galactic dimensions and distorted. The extended structure, which could be a pair of overlapping lobes, exhibits a strong depolarization asymmetry of the kind found in powerful double sources, while the core exhibits superluminal motion. 3C380 therefore has features to be expected of a Fanaroff-Riley class II source seen approximately end-on. However, from a detailed consideration of the new evidence we infer that the source is intrinsically small with an overall extent {le}60 kpc. (author).

  10. The DOPAS full-scale demonstation of plugs and seals project and related GRS national RD and D programs. A retrospective view on 24-month of investigation

    Energy Technology Data Exchange (ETDEWEB)

    Czaikowski, Oliver; Meyer, Thorsten; Miehe, Ruediger [GRS mbH, Braunschweig (Germany). Final Repository Safety Div.

    2015-07-01

    The DOPAS Full-Scale Demonstration of Plugs and Seals project consisting of 14 beneficiaries from 8 European countries brings forward important demonstration activities in plugging and sealing. These activities are also a part of each participants national long-term RD and D programm and are therefore jointly funded by Euratom's Seventh Framework Programme and national funding organizations. The Demonstration experiments which will be partially or wholly implemented during the DOPAS project are a full-scale seal (FSS) implemented in Saint-Dizier in France, an experimental pressure sealing plug (EPSP) underground in the Josef Gallery in Czech Republic, a deposition tunnel dome plug (DOMPLU) in the AespoeHard Rock Laboratory in Sweden, a deposition tunnel wedge plug (POPLU) in the underground rock characterization facility ONKALO (future spent fuel repository) in Finland, and components of a shaft sealing system (ELSA) in Germany (Dopas 2012). ELSA is a program of laboratory and in-situ experiments that will be used to further develop the reference shaft seal for the German disposal concept for a repository in rock salt and to develop reference shaft seals for a repository in clay host rocks (Kudla et al. 2013). On behalf of BMWi, the national funding organization for R and D work related to radioactive waste management, facing the ELSA project phase 3, GRS is investigating sealing and backfilling materials planned to be utilized in salt and clay formations. The program aims at providing experimental data needed for the theoretical analysis of the long-term sealing capacity of these sealing materials. According to current R and D work on the salt option, the shaft and drift seal components considered in Germany comprise seal components consisting of MgO and cement based salt concrete (Mueller-Hoeppe et al. 2012). In order to demonstrate hydro-mechanical material stability under representative load scenarios, the sealing capacity of the seal system and the impact

  11. iPTF13ehe in the context of Quark-Novae in massive binaries: double-humped, hydrogen-poor, superluminous Supernovae as standard candles

    CERN Document Server

    Ouyed, Rachid; Koning, Nico

    2015-01-01

    A Quark-Nova (QN; the explosive transition of a Neutron star to a Quark star) occurring in the second common envelope (CE) phase of a massive binary, as described in Ouyed et al. (2015a&b), gives excellent fits to super-luminous, hydrogen-poor, Supernovae (SLSNe) with double-humped light curves including DES13S2cmm, SN 2006oz and LSQ14bdq (see {\\it http://www.quarknova.ca/LCGallery.html}). In our model, the hydrogen envelope of the less massive companion is ejected during the first CE phase while the QN explosion occurs deep inside the He-rich second CE phase after it has expanded to its equilibrium configuration at ~1200Rsun; this yields the first hump in our model. The subsequent merging of the quark star with the CO core leads to black hole formation and accretion explaining the second long-lasting hump in our model, while the collision of the QN-ejected He-rich CE with the H-rich (i.e. first) CE accounts for late emission. Here we show that our model provides an excellent fit to the recently discovere...

  12. Detection of Broad H$\\alpha$ Emission Lines in the Late-time Spectra of a Hydrogen-poor Superluminous Supernova

    CERN Document Server

    Yan, Lin; Ofek, E; Gal-Yam, A; Mazzali, P; Perley, D; Vreeswijk, P; Leloudas, G; de Cia, A; Masci, F; Cenko, S B; Cao, Y; Kulkarni, S R; Nugent, P E; Rebbapragada, Umaa D; Woźniak, P R; Yaron, O

    2015-01-01

    iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z=0.3434, with properties similar to SN2007bi. It rises within (83-148)days (rest-frame) to reach a peak bolometric luminosity of 1.3x$10^{44}$erg/s, then decays very slowly at 0.015mag. per day. The measured ejecta velocity is 13000km/s. The inferred explosion characteristics, such as the ejecta mass (67-220$M_\\odot$), the total radiative and kinetic energy ($10^{51}$ & 2x$10^{53}$erg respectively), is typical of SLSN-R events. However, the late-time spectrum taken at +251days reveals a Balmer Halpha emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ~4500km/s and has a ~300km/s blue-ward shift relative to the narrow component. We interpret this broad Halpha emission line as the interaction between the supernova ejecta and a H-rich circumstellar medium (CSM) shell, located at a distance of ~4x$10^{16}$cm from the explosion site. This eje...

  13. Highly Luminous Supernovae associated with Gamma-Ray Bursts I.: GRB 111209A/SN 2011kl in the Context of Stripped-Envelope and Superluminous Supernovae

    CERN Document Server

    Kann, D A; E., F Olivares; Klose, S; Rossi, A; Perley, D A; Krühler, T; Greiner, J; Guelbenzu, A Nicuesa; Elliott, J; Knust, F; Filgas, R; Pian, E; Mazzali, P; Fynbo, J P U; Leloudas, G; Afonso, P M J; Delvaux, C; Graham, J F; Rau, A; Schmidl, S; Schulze, S; Tanga, M; Updike, A C; Varela, K

    2016-01-01

    We address the question whether GRB 111209A was a special event beyond its extreme duration alone, and whether it is a classical GRB or another kind of high-energy transient. Furthermore, we place SN 2011kl into the context of large samples of SNe, addressing in more detail the question of whether it could be radioactively powered. We present afterglow photometry obtained in seven bands with the GROND imager as well as in further seven bands with the UVOT telescope on-board \\emph{Swift}. The light curve is analysed by multi-band modelling and joint fitting with power-laws and broken power-laws. We model SN 2011kl using SN 1998bw as a template and derive a bolometric light curve including near-infrared data. We compare the optical afterglow and the properties of SN 2011kl to large ensembles we have analysed in earlier works, additional GRB-SNe analysed here, as well as literature results on stripped-envelope and superluminous supernovae. We find a strong, chromatic rebrightening event at $\\approx0.8$ days afte...

  14. Superluminous Supernova SN 2015bn in the Nebular Phase: Evidence for the Engine-powered Explosion of a Stripped Massive Star

    Science.gov (United States)

    Nicholl, M.; Berger, E.; Margutti, R.; Chornock, R.; Blanchard, P. K.; Jerkstrand, A.; Smartt, S. J.; Arcavi, I.; Challis, P.; Chambers, K. C.; Chen, T.-W.; Cowperthwaite, P. S.; Gal-Yam, A.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Kankare, E.; Magnier, E. A.; Maguire, K.; Mazzali, P. A.; McCully, C.; Milisavljevic, D.; Smith, K. W.; Taubenberger, S.; Valenti, S.; Wainscoat, R. J.; Yaron, O.; Young, D. R.

    2016-09-01

    We present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova (SLSN) SN 2015bn, at redshift z = 0.1136, spanning +250-400 days after maximum light. The light curve exhibits a steepening in the decline rate from 1.4 mag (100 days)-1 to 1.7 mag (100 days)-1, suggestive of a significant decrease in the opacity. This change is accompanied by a transition from a blue continuum superposed with photospheric absorption lines to a nebular spectrum dominated by emission lines of oxygen, calcium, and magnesium. There are no obvious signatures of circumstellar interaction or large 56Ni mass. We show that the spectrum at +400 days is virtually identical to a number of energetic SNe Ic such as SN 1997dq, SN 2012au, and SN 1998bw, indicating similar core conditions and strengthening the link between “hypernovae”/long gamma-ray bursts and SLSNe. A single explosion mechanism may unify these events that span absolute magnitudes of -22 < M B < -17. Both the light curve and spectrum of SN 2015bn are consistent with an engine-driven explosion ejecting 7-30 M ⊙ of oxygen-dominated ejecta (for reasonable choices in temperature and opacity). A strong and relatively narrow O i λ7774 line, seen in a number of these energetic events but not in normal supernovae, may point to an inner shell that is the signature of a central engine.

  15. A Selection of Giant Radio Sources from NVSS

    Science.gov (United States)

    Proctor, D. D.

    2016-06-01

    Results of the application of pattern-recognition techniques to the problem of identifying giant radio sources (GRSs) from the data in the NVSS catalog are presented, and issues affecting the process are explored. Decision-tree pattern-recognition software was applied to training-set source pairs developed from known NVSS large-angular-size radio galaxies. The full training set consisted of 51,195 source pairs, 48 of which were known GRSs for which each lobe was primarily represented by a single catalog component. The source pairs had a maximum separation of 20\\prime and a minimum component area of 1.87 square arcmin at the 1.4 mJy level. The importance of comparing the resulting probability distributions of the training and application sets for cases of unknown class ratio is demonstrated. The probability of correctly ranking a randomly selected (GRS, non-GRS) pair from the best of the tested classifiers was determined to be 97.8 ± 1.5%. The best classifiers were applied to the over 870,000 candidate pairs from the entire catalog. Images of higher-ranked sources were visually screened, and a table of over 1600 candidates, including morphological annotation, is presented. These systems include doubles and triples, wide-angle tail and narrow-angle tail, S- or Z-shaped systems, and core-jets and resolved cores. While some resolved-lobe systems are recovered with this technique, generally it is expected that such systems would require a different approach.

  16. No apparent superluminal motion in the first-known jetted tidal disruption event Swift J1644+5734

    CERN Document Server

    Yang, J; Gurvits, L I; Campbell, R M; Giannios, D; An, T; Komossa, S

    2016-01-01

    The first-known tidal disruption event (TDE) with strong evidence for a relativistic jet -- based on extensive multi-wavelength campaigns -- is Swift J1644+5734. In order to directly measure the apparent speed of the radio jet, we performed very long baseline interferometry (VLBI) observations with the European VLBI network (EVN) at 5 GHz. Our observing strategy was to identify a very nearby and compact radio source with the real-time e-EVN, and then utilise this source as a stationary astrometry reference point in the later five deep EVN observations. With respect to the in-beam source FIRST J1644+5736, we have achieved a statistical astrometric precision about 12 micro-arcsecond (68 % confidence level) per epoch. This is one of the best phase-referencing measurements available to date. No proper motion has been detected in the Swift J1644+5734 radio ejecta. We conclude that the apparent average ejection speed between 2012.2 and 2015.2 was less than 0.3c with a confidence level of 99 %. This tight limit is d...

  17. No apparent superluminal motion in the first-known jetted tidal disruption event Swift J1644+5734

    Science.gov (United States)

    Yang, J.; Paragi, Z.; van der Horst, A. J.; Gurvits, L. I.; Campbell, R. M.; Giannios, D.; An, T.; Komossa, S.

    2016-10-01

    The first-known tidal disruption event (TDE) with strong evidence for a relativistic jet - based on extensive multiwavelength campaigns - is Swift J1644+5734. In order to directly measure the apparent speed of the radio jet, we performed very long baseline interferometry (VLBI) observations with the European VLBI network (EVN) at 5 GHz. Our observing strategy was to identify a very nearby and compact radio source with the real-time e-EVN, and then utilize this source as a stationary astrometry reference point in the later five deep EVN observations. With respect to the in-beam source FIRST J1644+5736, we have achieved a statistical astrometric precision about 12 μas (68 per cent confidence level) per epoch. This is one of the best phase-referencing measurements available to date. No proper motion has been detected in the Swift J1644+5734 radio ejecta. We conclude that the apparent average ejection speed between 2012.2 and 2015.2 was less than 0.3c with a confidence level of 99 per cent. This tight limit is direct observational evidence for either a very small viewing angle or a strong jet deceleration due to interactions with a dense circum-nuclear medium, in agreement with some recent theoretical studies.

  18. POSSIBLE DETECTION OF APPARENT SUPERLUMINAL INWARD MOTION IN MARKARIAN 421 AFTER THE GIANT X-RAY FLARE IN 2010 FEBRUARY

    Energy Technology Data Exchange (ETDEWEB)

    Niinuma, K. [Graduate School of Science and Engineering, Yamaguchi University, Yamaguchi 753-8511 (Japan); Kino, M.; Oyama, T. [Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Nagai, H. [ALMA-J Project, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Isobe, N. [Institute of Space and Astronautics, Japan Aerospace Exploration Agency, Yoshinodai, Chuo, Sagamihara 252-5210 (Japan); Gabanyi, K. E. [Hungarian Academy of Sciences, Research Group for Physical Geodesy and Geodynamics, FOMI Satellite Geodetic Observatory Budapest, 1592 Budapest (Hungary); Hada, K. [INAF Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Koyama, S. [Department of Astronomy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8654 (Japan); Asada, K. [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 10617, Taiwan (China); Fujisawa, K., E-mail: niinuma@yamaguchi-u.ac.jp [Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511 (Japan)

    2012-11-10

    We report on the very long baseline interferometry (VLBI) follow-up observations using the Japanese VLBI Network array at 22 GHz for the largest X-ray flare of TeV blazar Mrk 421 that occurred in 2010 mid-February. The total of five epochs of observations were performed at intervals of about 20 days between 2010 March 7 and May 31. No newborn component associated with the flare was seen directly in the total intensity images obtained by our multi-epoch VLBI observations. However, one jet component located at {approx}1 mas northwest from the core was able to be identified, and its proper motion can be measured as -1.66 {+-} 0.46 mas yr{sup -1}, which corresponds to an apparent velocity of -3.48 {+-} 0.97c. Here, this negative velocity indicates that the jet component was apparently moving toward the core. As the most plausible explanation, we discuss that the apparent negative velocity was possibly caused by the ejection of a new component, which could not be resolved with our observations. In this case, the obtained Doppler factor of the new component is around 10-20, which is consistent with the ones typically estimated by model fittings of spectral energy distribution for this source.

  19. PS1-10afx AT z = 1.388: PAN-STARRS1 DISCOVERY OF A NEW TYPE OF SUPERLUMINOUS SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Chornock, R.; Berger, E.; Milisavljevic, D.; Lunnan, R.; Foley, R. J.; Soderberg, A. M.; Challis, P.; Czekala, I.; Drout, M.; Fong, W.; Kirshner, R. P.; McLeod, B.; Marion, G. H.; Narayan, G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Smartt, S. J. [Astrophysics Research Centre, School of Mathematics and Physics, Queen' s University Belfast, Belfast, BT7 1NN (United Kingdom); Burgasser, A. J. [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States); Chomiuk, L. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Huber, M. E. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Leibler, C., E-mail: rchornock@cfa.harvard.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95060 (United States); and others

    2013-04-20

    We present the Pan-STARRS1 discovery of PS1-10afx, a unique hydrogen-deficient superluminous supernova (SLSN) at redshift z = 1.388. The light curve peaked at z{sub P1} = 21.7 mag, making PS1-10afx comparable to the most luminous known SNe, with M{sub u} = -22.3 mag. Our extensive optical and near-infrared observations indicate that the bolometric light curve of PS1-10afx rose on the unusually fast timescale of {approx}12 days to the extraordinary peak luminosity of 4.1 Multiplication-Sign 10{sup 44} erg s{sup -1} (M{sub bol} = -22.8 mag) and subsequently faded rapidly. Equally important, the spectral energy distribution is unusually red for an SLSN, with a color temperature of {approx}6800 K near maximum light, in contrast to previous hydrogen-poor SLSNe, which are bright in the ultraviolet (UV). The spectra more closely resemble those of a normal SN Ic than any known SLSN, with a photospheric velocity of {approx}11, 000 km s{sup -1} and evidence for line blanketing in the rest-frame UV. Despite the fast rise, these parameters imply a very large emitting radius ({approx}> 5 Multiplication-Sign 10{sup 15} cm). We demonstrate that no existing theoretical model can satisfactorily explain this combination of properties: (1) a nickel-powered light curve cannot match the combination of high peak luminosity with the fast timescale; (2) models powered by the spindown energy of a rapidly rotating magnetar predict significantly hotter and faster ejecta; and (3) models invoking shock breakout through a dense circumstellar medium cannot explain the observed spectra or color evolution. The host galaxy is well detected in pre-explosion imaging with a luminosity near L*, a star formation rate of {approx}15 M{sub Sun} yr{sup -1}, and is fairly massive ({approx}2 Multiplication-Sign 10{sup 10} M{sub Sun }), with a stellar population age of {approx}10{sup 8} yr, also in contrast to the young dwarf hosts of known hydrogen-poor SLSNe. PS1-10afx is distinct from known examples of

  20. OPERA超光速中微子与人类对时空观的认识历程%OPERA Superluminal Neutrinos and Evolutions of Spacetime Concepts

    Institute of Scientific and Technical Information of China (English)

    邵立晶; 马伯强

    2011-01-01

    The understanding of space and time is the most important aspect of theoretical physics, and the current foundation of modern physics is based upon Einstein's relativistic spacetime. However, OPERA collaboration recently published their finding that muon neutrinos might travel faster than light, if proved, which will present a big revolution of Einstein's spacetime concepts. In this paper, we discuss OPERA superluminal neutrinos from experimental discoveries, possible theoretical interpretations, its relationship to the concepts of spacetime, and possible directions for experimental and theoretical researches. Since the understanding of spacetime is extremely important, we expect further experimental evidence to support or falsify OPERA result, and improve our knowledge of spacetime.%物理学对于时间与空间的理解,是推动其发展的重要因素。而现代物理学的根基,则是建立在爱因斯坦的相对论时空观上的。最近,OPERA合作研究组却发现了存在超光速中微子的可能性.倘若其被证实,将是对相对论时空观的一次重大挑战。本文从实验发现,可能的理论解释,人们对于时空观的认识等方面入手,较为客观地讨论了OPERA的实验结果,指出了其可能的实验与理论的研究方向。由于对于时空观的认识是个极其重要的过程,所以我们期待更多的实验来证实或者证伪OPERA超光速中微子的结果,从而推动物理学对于时空观的认识。

  1. The Superluminous Supernova SN 2017egm in the Nearby Galaxy NGC 3191: A Metal-rich Environment Can Support a Typical SLSN Evolution

    Science.gov (United States)

    Nicholl, Matt; Berger, Edo; Margutti, Raffaella; Blanchard, Peter K.; Guillochon, James; Leja, Joel; Chornock, Ryan

    2017-08-01

    At redshift z = 0.03, the recently discovered SN 2017egm is the nearest Type I superluminous supernova (SLSN) to date and first near the center of a massive spiral galaxy (NGC 3191). Using SDSS spectra of NGC 3191, we find a metallicity ˜2 {Z}⊙ at the nucleus and ˜1.3 {Z}⊙ for a star-forming region at a radial offset similar to SN 2017egm. Archival radio-to-UV photometry reveals a star formation rate of ˜15 {M}⊙ yr-1 (with ˜70% dust obscured), which can account for a Swift X-ray detection and a stellar mass of ˜ {10}10.7 {M}⊙ . We model the early UV-optical light curves with a magnetar central-engine model, using the Bayesian light curve fitting tool MOSFiT. The fits indicate an ejecta mass of 2-4 {M}⊙ , a spin period of 4-6 ms, a magnetic field of (0.7{--}1.7)× {10}14 G, and a kinetic energy of 1{--}2× {10}51 erg. These parameters are consistent with the overall distributions for SLSNe, modeled by Nicholl et al., although the derived mass and spin are toward the low end, possibly indicating an enhanced loss of mass and angular momentum before explosion. This has two implications: (i) SLSNe can occur at solar metallicity, although with a low fraction of ˜10%, and (ii) metallicity has at most a modest effect on their properties. Both conclusions are in line with results for long gamma-ray bursts. Assuming a monotonic rise gives an explosion date of MJD 57889 ± 1. However, a short-lived excess in the data relative to the best-fitting models may indicate an early-time “bump.” If confirmed, SN 2017egm would be the first SLSN with a spectrum during the bump phase; this shows the same O ii lines seen at maximum light, which may be an important clue for explaining these bumps.

  2. SIGMA discovery of a transient hard X-ray source in the galactic center region.

    Science.gov (United States)

    Vargas, M.; Goldwurm, A.; Paul, J.; Denis, M.; Borrel, V.; Bouchet, L.; Roques, J. P.; Jourdain, E.; Trudolyubov, S.; Gilfanov, M.; Churazov, E.; Sunyaev, R.; Khavenson, N.; Dyachkov, A.; Novikov, B.; Chulkov, I.

    1996-09-01

    A new X-ray transient source, GRS 1730-312 (=KS 1730-312), was discovered by the hard X-ray/soft γ-ray coded mask telescope SIGMA/GRANAT in the Galactic Center region during observations performed in September 1994. The flare started on September 22 and lasted approximately 3days, during which the source became the brightest object of the region at energies above 35keV. The average 35-200keV spectrum can be described by a power law with photon index of -2.5 or by a thermal bremsstrahlung model with kT_e_=~70keV. SIGMA data have been found consistent with the spectral shape and with the spectral evolution observed by the TTM/Mir-Kvant telescope at lower energies. This new source belongs to the population of hard X-ray sources already detected by SIGMA in the direction of the Galactic Bulge region.

  3. A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and \\textit{RXTE} observations

    CERN Document Server

    Abdalla, H; Aharonian, F; Benkhali, F Ait; Akhperjanian, A G; Angüner, E O; Arrieta, M; Aubert, P; Backes, M; Balzer, A; Barnard, M; Becherini, Y; Tjus, J Becker; Berge, D; Bernhard, S; Bernlöhr, K; Birsin, E; Blackwell, R; Böttcher, M; Boisson, C; Bolmont, J; Bordas, P; Bregeon, J; Brun, F; Brun, P; Bryan, M; Bulik, T; Capasso, M; Carr, J; Casanova, S; Chadwick, P M; Chakraborty, N; Chalme-Calvet, R; Chaves, R C G; Chen, A; Chevalier, J; Chrétien, M; Colafrancesco, S; Cologna, G; Condon, B; Conrad, J; Couturier, C; Cui, Y; Davids, I D; Degrange, B; Deil, C; deWilt, P; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Donath, A; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; 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; Grudzińska, M; Hadasch, D; Hahn, J; Hawkes, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hillert, A; Hinton, J A; Hofmann, W; Hoischen, C; Holler, M; Horns, D; Ivascenko, A; Jacholkowska, A; Jamrozy, M; Janiak, M; Jankowsky, D; Jankowsky, F; Jingo, M; Jogler, T; Jouvin, L; Jung-Richardt, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kerszberg, D; Khélifi, B; Kieffer, M; King, J; Klepser, S; Klochkov, D; Kluźniak, W; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Kraus, M; Krayzel, F; Krüger, P P; Laffon, H; Lamanna, G; Lau, J; -P., J; Lefaucheur, J; Lefranc, V; Lemière, A; Lemoine-Goumard, M; Lenain, J -P; Leser, E; Lohse, T; Lorentz, M; Liu, R; Lypova, I; Marandon, V; Marcowith, A; Mariaud, C; Marx, R; Maurin, G; Maxted, N; Mayer, M; Meintjes, P J; Menzler, U; Meyer, M; Mitchell, A M W; Moderski, R; Mohamed, M; Morå, K; Moulin, E; Murach, T; de Naurois, M; Niederwanger, F; Niemiec, J; Oakes, L; Odaka, H; Öttl, S; Ohm, S; Ostrowski, M; Oya, I; Padovani, M; Panter, M; Parsons, R D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Petrucci, P -O; Peyaud, B; Pita, S; Poon, H; Prokhorov, D; Prokoph, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Romoli, C; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Salek, D; Sanchez, D A; Santangelo, A; Sasaki, M; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwemmer, S; Seyffert, A S; Shafi, N; Shilon, I; Simoni, R; Sol, H; Spanier, F; Spengler, G; Spies, F; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Tavernet, J -P; Tavernier, T; Taylor, A M; Terrier, R; Tluczykont, M; Trichard, C; Tuffs, R; van der Walt, J; van Eldik, 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; Zdziarski, A A; Zech, A; Zefi, F; Ziegler, A; Żywucka, N

    2016-01-01

    Microquasars are potential $\\gamma$-ray emitters. Indications of transient episodes of $\\gamma$-ray emission were recently reported in at least two systems: Cyg X-1 and Cyg X-3. The identification of additional $\\gamma$-ray-emitting microquasars is required to better understand how $\\gamma$-ray emission can be produced in these systems. Theoretical models have predicted very high-energy (VHE) $\\gamma$-ray emission from microquasars during periods of transient outburst. Observations reported herein were undertaken with the objective of observing a broadband flaring event in the $\\gamma$-ray and X-ray bands. Contemporaneous observations of three microquasars, GRS 1915+105, Circinus X-1, and V4641 Sgr, were obtained using the High Energy Spectroscopic System (H.E.S.S.) telescope array and the Rossi X-ray Timing Explorer (RXTE) satellite. X-ray analyses for each microquasar were performed and VHE $\\gamma$-ray upper limits from contemporaneous H.E.S.S. observations were derived. No significant $\\gamma$-ray signal ...

  4. 光纤中基于布里渊激光振荡的超光速传输首次在实验上实现%Superluminal Propagation in Optical Fibers Based on Brillouin Lasing Oscillation First Demonstrated

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    上海交通大学物理系詹黎教授(图1)以及其博士研究生张亮(图2)首次在实验上实现了光纤中基于布里渊激光振荡的低损耗长距离超光速传输,其研究成果以"Superluminal propagation at negative groupvelocity in optical fibers based on Brillouin lasing oscillation"为标题发表在物理领域国际顶级期刊物理评论快报( Physical Review Letters)(Phys.Rev.Lett.,Vol.107,093903,2011).

  5. 基于截面和时序GRS检验的流动性定价研究%Liquidity Pricing Research Based on Cross-Section and Time Series GRS Tests

    Institute of Scientific and Technical Information of China (English)

    刘锋; 霍德明

    2012-01-01

    This study explores the role of liquidity in pricing stock returns in the Chinese stock market,by using a sample of A-share listed companies from Jan.1st,1996 to Dec.31st,2010.In the Fama-MacBeth regression,liquidity is significant after controlling for other factors and firm characteristics.In the time-series regression of characteristic-sorted portfolios,all liquidity loadings are almost significant and significant intercepts decrease dramatically.After adding the liquidity in regression models,the extreme ranges and the mean pricing errors decrease monotonically.The significant GRS Tests reveal that there are some other potential risk factors.%以1996年1月1日至2010年12月31日所有A股上市公司为样本,分析了流动性在股票回报定价中的作用。在Fama-MacBeth截面回归分析中,当控制了其他风险因子和特征变量后,流动性的定价作用仍然显著。在按特征变量分组的投资组合时间序列分析中,流动性载荷统计上显著,且显著的回归截距项明显减少。在稳健性检验中,加入流动性因子后,模型截距项的极差和平均定价误差均单调减少。当然GRS统计量的显著性表明,还存在其他潜在的风险定价因子。

  6. 2016 Microbial Stress Response GRC/GRS

    Science.gov (United States)

    2016-09-13

    Holyoke College South Hadley, MA Chairs: Eduardo A. Groisman & Dianne K. Newman Vice Chairs: Petra A. Levin & William W. Navarre Contributors...Wisconsin-Madison, USA) 7:30 pm - 7:55 pm James Williamson (The Scripps Research Institute, USA) "Macroeconomics of the Bacterial Proteome" 7:55 pm - 8...Technology Attendee Registered Levin, Petra A Washington University in St. Louis Vice Chair Registered Libby, Elizabeth Columbia University Speaker

  7. A 5-GHz Southern Hemisphere VLBI Survey of Compact Radio Sources, 2

    CERN Document Server

    Shen, Z Q; Moran, J M; Jauncey, D L; Reynolds, J E; Tzioumis, A K; Gough, R G; Ferris, R H; Sinclair, M W; Jiang, D R; Hong-Xing, Y; Liang, S G; Edwards, P G; Costa, M E; Tingay, S J; McCulloch, P M; Lovell, J E J; King, E A; Nicolson, G D; Murphy, D W; Meier, D L; Van Ommen, T D; White, G L

    1998-01-01

    We report the results of a 5-GHz southern-hemisphere snapshot VLBI observation of a sample of blazars. The observations were performed with the Southern Hemisphere VLBI Network plus the Shanghai station in 1993 May. Twenty-three flat-spectrum, radio-loud sources were imaged. These are the first VLBI images for 15 of the sources. Eight of the sources are EGRET (> 100 MeV) gamma-ray sources. The milliarcsecond morphology shows a core-jet structure for 12 sources, and a single compact core for the remaining 11. No compact doubles were seen. Compared with other radio images at different epochs and/or different frequencies, 3 core-jet blazars show evidence of bent jets, and there is some evidence for superluminal motion in the cases of 2 blazars. The detailed descriptions for individual blazars are given. This is the second part of a survey: the first part was reported by Shen et al. (AJ 114(1997)1999).

  8. Source Water Protection Contaminant Sources

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Simplified aggregation of potential contaminant sources used for Source Water Assessment and Protection. The data is derived from IDNR, IDALS, and US EPA program...

  9. Design of a Free and Open Source Data Processing, Archiving, and Distribution Subsystem for the Ground Receiving Station of the Philippine Scientific Earth Observation Micro-Satellite

    Science.gov (United States)

    Aranas, R. K. D.; Jiao, B. J. D.; Magallon, B. J. P.; Ramos, M. K. F.; Amado, J. A.; Tamondong, A. M.; Tupas, M. E. A.

    2016-06-01

    The Philippines's PHL-Microsat program aims to launch its first earth observation satellite, DIWATA, on the first quarter of 2016. DIWATA's payload consists of a high-precision telescope (HPT), spaceborne multispectral imager (SMI) with liquid crystal tunable filter (LCTF), and a wide field camera (WFC). Once launched, it will provide information about the Philippines, both for disaster and environmental applications. Depending on the need, different remote sensing products will be generated from the microsatellite sensors. This necessitates data processing capability on the ground control segment. Rather than rely on commercial turnkey solutions, the PHL-Microsat team, specifically Project 3:DPAD, opted to design its own ground receiving station data subsystems. This paper describes the design of the data subsystems of the ground receiving station (GRS) for DIWATA. The data subsystems include: data processing subsystem for automatic calibration and georeferencing of raw images as well as the generation of higher level processed data products; data archiving subsystem for storage and backups of both raw and processed data products; and data distribution subsystem for providing a web-based interface and product download facility for the user community. The design covers the conceptual design of the abovementioned subsystems, the free and open source software (FOSS) packages used to implement them, and the challenges encountered in adapting the existing FOSS packages to DIWATA GRS requirements.

  10. DESIGN OF A FREE AND OPEN SOURCE DATA PROCESSING, ARCHIVING, AND DISTRIBUTION SUBSYSTEM FOR THE GROUND RECEIVING STATION OF THE PHILIPPINE SCIENTIFIC EARTH OBSERVATION MICRO-SATELLITE

    Directory of Open Access Journals (Sweden)

    R. K. D. Aranas

    2016-06-01

    Full Text Available The Philippines’s PHL-Microsat program aims to launch its first earth observation satellite, DIWATA, on the first quarter of 2016. DIWATA’s payload consists of a high-precision telescope (HPT, spaceborne multispectral imager (SMI with liquid crystal tunable filter (LCTF, and a wide field camera (WFC. Once launched, it will provide information about the Philippines, both for disaster and environmental applications. Depending on the need, different remote sensing products will be generated from the microsatellite sensors. This necessitates data processing capability on the ground control segment. Rather than rely on commercial turnkey solutions, the PHL-Microsat team, specifically Project 3:DPAD, opted to design its own ground receiving station data subsystems. This paper describes the design of the data subsystems of the ground receiving station (GRS for DIWATA. The data subsystems include: data processing subsystem for automatic calibration and georeferencing of raw images as well as the generation of higher level processed data products; data archiving subsystem for storage and backups of both raw and processed data products; and data distribution subsystem for providing a web-based interface and product download facility for the user community. The design covers the conceptual design of the abovementioned subsystems, the free and open source software (FOSS packages used to implement them, and the challenges encountered in adapting the existing FOSS packages to DIWATA GRS requirements.

  11. Sourcing Excellence

    DEFF Research Database (Denmark)

    Adeyemi, Oluseyi

    2011-01-01

    Sourcing Excellence is one of the key performance indicators (KPIs) in this world of ever changing sourcing strategies. Manufacturing companies need to access and diagnose the reliability and competencies of existing suppliers in order to coordinate and develop them. This would help in managing...

  12. Sourcing Excellence

    DEFF Research Database (Denmark)

    Adeyemi, Oluseyi

    2011-01-01

    Sourcing Excellence is one of the key performance indicators (KPIs) in this world of ever changing sourcing strategies. Manufacturing companies need to access and diagnose the reliability and competencies of existing suppliers in order to coordinate and develop them. This would help in managing...... in manufacturing companies. In addition, an advanced approach to sourcing involves integrating and coordinating suppliers, common materials, processes, designs and technologies across worldwide buying, design and operating locations. However, since most manufacturing companies do not have well-developed suppliers...... for global sourcing strategies in place, improvement opportunities in this area are attractive and as yet largely unrealized. Shifting from a narrow, cost-reduction emphasis with suppliers to an emphasis on globally integrated and coordinated sourcing strategies with well-developed suppliers would improve...

  13. German Support Program for Retrieval and Safe Storage of Disused Radioactive Sealed Sources in Ukraine - 13194

    Energy Technology Data Exchange (ETDEWEB)

    Pretzsch, Gunter; Salewski, Peter; Sogalla, Martin [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Kurfuerstendamm 200, 10719 Berlin (Germany)

    2013-07-01

    The German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) on behalf of the Government of the Federal Republic of Germany supports the State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) in enhancement of nuclear safety and radiation protection and strengthening of the physical protection. One of the main objectives of the agreement concluded by these parties in 2008 was the retrieval and safe interim storage of disused orphan high radioactive sealed sources in Ukraine. At present, the Ukrainian National Registry does not account all high active radiation sources but only for about 70 - 80 %. GRS in charge of BMU to execute the program since 2008 concluded subcontracts with the waste management and interim storage facilities RADON at different regions in Ukraine as well with the waste management and interim storage facility IZOTOP at Kiev. Below selected examples of removal of high active Co-60 and Cs-137 sources from irradiation facilities at research institutes are described. By end of 2012 removal and safe interim storage of 12.000 disused radioactive sealed sources with a total activity of more than 5,7.10{sup 14} Bq was achieved within the frame of this program. The German support program will be continued up to the end of 2013 with the aim to remove and safely store almost all disused radioactive sealed sources in Ukraine. (authors)

  14. Ejector and propeller spin-down: how might a superluminous supernova millisecond magnetar become the 6.67 h pulsar in RCW 103

    Science.gov (United States)

    Ho, Wynn C. G.; Andersson, Nils

    2017-01-01

    The X-ray source 1E 161348-5055 in the supernova remnant RCW 103 recently exhibited X-ray activity typical of magnetars, i.e. neutron stars with magnetic fields ≳ 1014-1015 G. However, 1E 161348-5055 has an observed period of 6.67 h, in contrast to magnetars which have a spin period of seconds. Here we describe a simple model which can explain the spin evolution of 1E 161348-5055, as well as other magnetars, from an initial period of milliseconds that would be required for dynamo generation of magnetar-strength magnetic fields. We propose that the key difference between 1E 161348-5055 and other magnetars is the persistence of a remnant disc of small total mass. This disc caused 1E 161348-5055 to undergo ejector and propeller phases in its life, during which strong torques caused a rapid increase of its spin period. By matching its observed spin period and ≈1-3 kyr age, we find that 1E 161348-5055 has the (slightly) highest magnetic field of all known magnetars, with B ˜ 5 × 1015 G, and that its disc had a mass of ˜1024 g, comparable to that of the asteroid Ceres.

  15. Ejector and propeller spin-down: How might a superluminous supernova millisecond magnetar become the 6.67 hr pulsar in RCW103

    CERN Document Server

    Ho, Wynn C G

    2016-01-01

    The X-ray source 1E 161348-5055 in the supernova remnant RCW 103 recently exhibited X-ray activity typical of magnetars, i.e., neutron stars with magnetic fields > 10^14-10^15 G. However, 1E 161348-5055 has an observed period of 6.67 hr, in contrast to magnetars which have a spin period of seconds. Here we describe a simple model which can explain the spin evolution of 1E 161348-5055, as well as other magnetars, from an initial period of milliseconds that would be required for dynamo generation of magnetar-strength magnetic fields. We propose that the key difference between 1E 161348-5055 and other magnetars is the persistence of a remnant disk of small total mass. This disk caused 1E 161348-5055 to undergo ejector and propeller phases in its life, during which strong torques caused a rapid increase of its spin period. By matching its observed spin period and ~1-3 kyr age, we find that 1E 161348-5055 has the (slightly) highest magnetic field of all known magnetars, with B~5x10^15 G, and that its disk had a ma...

  16. Crowd Sourcing.

    Science.gov (United States)

    Baum, Neil

    2016-01-01

    The Internet has contributed new words and slang to our daily vernacular. A few terms, such as tweeting, texting, sexting, blogging, and googling, have become common in most vocabularies and in many languages, and are now included in the dictionary. A new buzzword making the rounds in industry is crowd sourcing, which involves outsourcing an activity, task, or problem by sending it to people or groups outside a business or a practice. Crowd sourcing allows doctors and practices to tap the wisdom of many instead of relying only on the few members of their close-knit group. This article defines "crowd sourcing," offers examples, and explains how to get started with this approach that can increase your ability to finish a task or solve problems that you don't have the time or expertise to accomplish.

  17. Fracture source

    Directory of Open Access Journals (Sweden)

    2003-07-01

    Full Text Available The fracture properties of many different types of fibers are covered in a timely new book that will prove to be a tremendous source of information and references for researchers in the wide and diverse field of fibers and composites, says Bill Clegg.

  18. Source term assessment with ASTEC and associated uncertainty analysis using SUNSET tool

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier-Jabet, K., E-mail: karine.chevalier-jabet@irsn.fr; Cousin, F.; Cantrel, L.; Séropian, C.

    2014-06-01

    Several accidental scenarios have been simulated using the ASTEC integral IRSN-GRS code for a French 1300 MWe PWR, including several break sizes or locations, highlighting the effect of safety systems and of iodine chemistry in the reactor coolant system (RCS) and in the containment on iodine source term evaluations. Iodine chemistry in the RCS and in the containment is still subject to significant uncertainties and it is thus studied in on-going R and D programs. To assess the impact of uncertainties, ASTEC has been coupled to the IRSN uncertainty propagation and sensitivity analysis tool SUNSET. Focusing on a loss of feed-water of steam generator accident, ASTEC/SUNSET calculations have been performed to assess the effect of remaining uncertainties relative to iodine behaviour on the source term. Calculations show that the postulated lack of knowledge may impact the iodine source term in the environment by at least one decade, confirming the importance of the on-going R and D programs to improve the knowledge on iodine chemistry.

  19. On the source of Faraday rotation in the jet of the radio galaxy 3C120

    CERN Document Server

    Gómez, José L; Agudo, Iván; Marscher, Alan P; Jorstad, Svetlana G

    2011-01-01

    The source of Faraday rotation in the jet of the radio galaxy 3C120 is analyzed through Very Long Baseline Array observations carried out between 1999 and 2007 at 86, 43, 22, 15, 12, 8, 5, 2, and 1.7 GHz. Comparison of observations from 1999 to 2001 reveals uncorrelated changes in the linear polarization of the underlying jet emission and the Faraday rotation screen: while the rotation measure (RM) remains constant between approximately 2 and 5 mas from the core, the RM-corrected electric vector position angles (EVPAs) of two superluminal components are rotated by almost 90 degrees when compared to other components moving through similar jet locations. On the other hand, the innermost 2 mas experiences a significant change in RM -- including a sign reversal -- but without variations in the RM-corrected EVPAs. Similarly, observations in 2007 reveal a double sign reversal in RM along the jet, while the RM-corrected EVPAs remain perpendicular to the jet axis. Although the observed coherent structure and gradient...

  20. Source rock

    OpenAIRE

    Abubakr F. Makky; Mohamed I. El Sayed; Ahmed S. Abu El-Ata; Ibrahim M. Abd El-Gaied; Mohamed I. Abdel-Fattah; Zakaria M. Abd-Allah

    2014-01-01

    West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro), and well log data of some Cretaceous sequences including Abu Roash (E, F and G members), Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history ...

  1. Superluminal Phenomena and the Quantum Preferred Frame

    CERN Document Server

    Rembielinski, J

    2000-01-01

    Motivated by a number of recent experiments, we discuss in this paper a speculative but physically admissible form and solutions of effective Maxwell-like equations describing propagation of electromagnetic field in a medium which ``feels'' a quantum preferred frame.

  2. A Superluminal Subway The Krasnikov Tube

    CERN Document Server

    Everett, A E; Everett, Allen E.; Roman, Thomas A.

    1997-01-01

    The ``warp drive'' metric recently presented by Alcubierre has the problem that an observer at the center of the warp bubble is causally separated from the outer edge of the bubble wall. Hence such an observer can neither create a warp bubble on demand nor control one once it has been created. In addition, such a bubble requires negative energy densities. One might hope that elimination of the first problem might ameliorate the second as well. We analyze and generalize a metric, originally proposed by Krasnikov for two spacetime dimensions, which does not suffer from the first difficulty. As a consequence, the Krasnikov metric has the interesting property that although the time for a one-way trip to a distant star cannot be shortened, the time for a round trip, as measured by clocks on Earth, can be made arbitrarily short. In our four dimensional extension of this metric, a ``tube'' is constructed along the path of an outbound spaceship, which connects the Earth and the star. Inside the tube spacetime is flat...

  3. Anti-correlated hard X-ray time lags in Galactic black hole sources

    CERN Document Server

    Sriram, K; Pendharkar, J K; Rao, A R; Pendharkar, Jayant K.

    2007-01-01

    We investigate the accretion disk geometry in Galactic black hole sources by measuring the time delay between soft and hard X-ray emissions. Similar to the recent discoveries of anti-correlated hard X-ray time lags in Cyg X-3 and GRS 1915+105, we find that the hard X-rays are anti-correlated with soft X-rays with a significant lag in another source: XTE J1550-564. We also find the existence of pivoting in the model independent X-ray spectrum during these observations. We investigate time-resolved X-ray spectral parameters and find that the variation in these parameters is consistent with the idea of a truncated accretion disk. The QPO frequency, which is a measure of the size of truncated accretion disk, too changes indicating that the geometric size of the hard X-ray emitting region changes along with the spectral pivoting and soft X-ray flux. Similar kind of delay is also noticed in 4U 1630-47.

  4. Open Source

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    一场秋雨一场凉,开源社区的气温却丝毫没有降。刚在北京闭幕的“2006中国开源世界高峰论坛”足以让世界侧目。国际大师云集是最大的亮点,很多熟悉的名字:Andrew Morton(Linux内核开发大师及2.6版本监护人)、Brian Behlendorf(Apache创始人)、David Axmark(MySQL创始人)、Marc Fleury(JBoss创始人)、Larry Augustin(Source Forge创始人)等;其次是中国政府、学术界的支持,包括国家信产部陈英司长和中国工程院倪光南院士、沈昌祥院士等;当然.少不了诸多跨国公司和国内知名企业的参与。

  5. Sources manuscrites

    OpenAIRE

    2014-01-01

    I. SOURCES CONSULTÉES AUX ARCHIVES NATIONALES Série E 1. Minutes d’arrêts du Conseil, arrêts simples en finances 1602 : E 4a, E 4b. 1605 : E 8a, E 8b, E 8c-9a, E 9b, E 9c. 1608 : E 16a, E 16b, E 18a, E 18b, E 19a, E 19b. 1620 : E 63a E 63b, E 64a, E 64b-65a, E 65b. 1689 : E 579a, E 579b, E 580, E 581, E 582, E 583, E 584a, E 584b, E 585a, E 585b, E 586a, E 586b 1750 : E 1260a E 1260b, E 1261a E 1261b, E 1262a, E 1262b, E 1262e, E 1263a, E 1263b, E 1264a, E 1264b, E 1265a, E 1265b, E 1266a, E ...

  6. Safety and Security of Radioactive Sealed and Disused/Orphan Sources in Ukraine - German Contribution - 13359

    Energy Technology Data Exchange (ETDEWEB)

    Brasser, Thomas; Hertes, Uwe; Meyer, Thorsten; Uhlenbruck, Hermann [Gesellschaft fuer Anlagen- und Reaktorsicherheit - GRS mbH, Theodor-Heuss-Str. 4, 38122 Braunschweig (Germany); Shevtsov, Alexey [Ukrainian State Production Company IZOTOP 152, Gorky str., 03680 Kiev (Ukraine)

    2013-07-01

    Within the scope of 'Nuclear Security of Radioactive Sources', the German government implemented the modernization of Ukrainian State Production Company's transport and storage facility for radioactive sources (TSF) in Kiev. The overall management of optimizing the physical protection of the storage facility (including the construction of a hot cell for handling the radioactive sources) is currently carried out by the German Federal Foreign Office (AA). AA jointly have assigned Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Germany's leading expert institution in the area of nuclear safety and waste management, to implement the project and to ensure transparency by financial and technical monitoring. Sealed radioactive sources are widely used in industry, medicine and research. Their life cycle starts with the production and finally ends with the interim/long-term storage of the disused sources. In Ukraine, IZOTOP is responsible for all radioactive sources throughout their life cycle. IZOTOP's transport and storage facility (TSF) is the only Ukrainian storage facility for factory-fresh radioactive sources up to an activity of about 1 million Ci (3.7 1016 Bq). The TSF is specially designed for the storage and handling of radioactive sources. Storage began in 1968, and is licensed by the Ukrainian state authorities. Beside the outdated state of TSF's physical protection and the vulnerability of the facility linked with it, the lack of a hot cell for handling and repacking radioactive sources on the site itself represents an additional potential hazard. The project, financed by the German Federal Foreign Office, aims to significantly improve the security of radioactive sources during their storage and handling at the TSF site. Main tasks of the project are a) the modernization of the physical protection of the TSF itself in order to prevent any unauthorized access to radioactive sources as well as b) the construction of a hot

  7. The relationship between the radio core dominance parameter and the spectral index in different classes of extragalactic radio sources

    Institute of Scientific and Technical Information of China (English)

    Jun-Hui Fan; Jiang-He Yang; Jing Pan; Tong-Xu Hua

    2011-01-01

    Active galactic nuclei (AGNs) have two major classes,namely radio loud AGNs and radio quiet AGNs.A small subset of the radio-loud AGNs is called blazars,which display extreme observational properties,such as rapid variability,high Iuminosity,high and variable polarization,and superluminal motion.All of those observational properties are probably due to a relativistic beaming effect with the jet pointing close to the line of sight.Observations suggest that the orientation can be expressed by a core-dominance parameter,R.The R,to some extent,is associated with the beaming effect.Blazars are believed to be unified with Fanaroff & Riley type I/Ⅱ (FRI/Ⅱ)radio galaxies.In this work,we collected relevant observations from the literature for a sample of 1223 AGNs including 77 BL Lacertae objects,495 quasars,460 galaxies,119 FRs and 72 unidentified sources,and calculated the core-dominance parameters and spectral indexes,discussed the relationship between the two parameters,and gave some discussions.Our analysis suggests that the core-dominance parameters in BL Lacertae objects are larger than those in quasars and galaxies,and the radio spectral indexes in BL Lacertae objects are lower than those in quasars and galaxies.We also found that the core-dominance parameter-spectral index correlation exists for a large sample presented in this work,which may come from a relativistic beaming effect.

  8. First Results from Fermi GBM Earth Occultation Monitoring: Observations of Soft Gamma-Ray Sources Above 100 keV

    CERN Document Server

    Case, Gary L; Rodi, James C; Jenke, Peter; Wilson-Hodge, Colleen A; Finger, Mark H; Meegan, Charles A; Camero-Arranz, Ascencion; Beklen, Elif; Bhat, P Narayan; Briggs, Michael S; Chaplin, Vandiver; Connaughton, Valerie; Paciesas, William S; Preece, Robert; Kippen, R Marc; von Kienlin, Andreas; Griener, Jochen

    2010-01-01

    The NaI and BGO detectors on the Gamma-ray Burst Monitor (GBM) on Fermi are now being used for long-term monitoring of the hard X-ray/low energy gamma-ray sky. Using the Earth occultation technique as demonstrated previously by the BATSE instrument on the Compton Gamma-Ray Observatory, GBM can be used to produce multiband light curves and spectra for known sources and transient outbursts in the 8 keV to 1 MeV energy range with its NaI detectors and up to 40 MeV with its BGO detectors. Over 85% of the sky is viewed every orbit, and the precession of the Fermi orbit allows the entire sky to be viewed every ~26 days with sensitivity exceeding that of BATSE at energies below ~25 keV and above ~1.5 MeV. We briefly describe the technique and present preliminary results using the NaI detectors after the first two years of observations at energies above 100 keV. Eight sources are detected with a significance greater than 7 sigma: the Crab, Cyg X-1, SWIFT J1753.5-0127, 1E 1740-29, Cen A, GRS 1915+105, and the transien...

  9. GRS evidence and the possibility of paleooceans on Mars

    Science.gov (United States)

    Dohm, J.M.; Baker, V.R.; Boynton, W.V.; Fairen, A.G.; Ferris, J.C.; Finch, M.; Furfaro, R.; Hare, T.M.; Janes, D.M.; Kargel, J.S.; Karunatillake, S.; Keller, J.; Kerry, K.; Kim, K.J.; Komatsu, G.; Mahaney, W.C.; Schulze-Makuch, D.; Marinangeli, L.; Ori, G.G.; Ruiz, J.; Wheelock, S.J.

    2009-01-01

    The Gamma Ray Spectrometer (Mars Odyssey spacecraft) has revealed elemental distributions of potassium (K), thorium (Th), and iron (Fe) on Mars that require fractionation of K (and possibly Th and Fe) consistent with aqueous activity. This includes weathering, evolution of soils, and transport, sorting, and deposition, as well as with the location of first-order geomorphological demarcations identified as possible paleoocean boundaries. The element abundances occur in patterns consistent with weathering in situ and possible presence of relict or exhumed paleosols, deposition of weathered materials (salts and clastic minerals), and weathering/transport under neutral to acidic brines. The abundances are explained by hydrogeology consistent with the possibly overlapping alternatives of paleooceans and/or heterogeneous rock compositions from diverse provenances (e.g., differing igneous compositions). ?? 2008 Elsevier Ltd.

  10. Multicusp ion sources (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N. (Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States))

    1994-04-01

    During the last decade, different types of multicusp ion sources, such as high current, high concentration H[sup +], H[sup +][sub 2], or N[sup +] ion sources, negative ion sources, radio-frequency-driven sources, and high charge state ion sources have been developed at the Lawrence Berkeley Laboratory. This article reviews the history of the research and development of these ion sources and their applications.

  11. Software testing and source code for the calculation of clearance values. Final report; Erprobung von Software und Quellcode zur Berechnung von Freigabewerten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Artmann, Andreas; Meyering, Henrich

    2016-11-15

    The GRS research project was aimed to the test the appropriateness of the software package ''residual radioactivity'' (RESRAD) for the calculation of clearance values according to German and European regulations. Comparative evaluations were performed with RESRAD-OFFSITE and the code SiWa-PRO DSS used by GRS and the GRS program code ARTM. It is recommended to use RESRAD-OFFSITE for comparative calculations. The dose relevant air-path dispersion of radionuclides should not be modeled using RESRAD-OFFSITE, the use of ARTM is recommended. The sensitivity analysis integrated into RESRAD-OFFSITE allows a fast identification of crucial parameters.

  12. Mesoscale, Sources and Models: Sources for Nitrogen in the Atmosphere

    DEFF Research Database (Denmark)

    Hertel, O.

    1994-01-01

    Projektet Mesoscales, Sources and Models: Sources for Nitrogen in the Atmosphere er opdelt i 3 delprojekter: Sources - farmland, Sources - sea og Sources - biogenic nitrogen.......Projektet Mesoscales, Sources and Models: Sources for Nitrogen in the Atmosphere er opdelt i 3 delprojekter: Sources - farmland, Sources - sea og Sources - biogenic nitrogen....

  13. Sources management; La gestion des sources

    Energy Technology Data Exchange (ETDEWEB)

    Mansoux, H.; Gourmelon; Scanff, P.; Fournet, F. [Institut de Radioprotection et de Surete Nucleaire, 92 - Fontenay-aux-Roses (France); Murith, Ch. [Office Federal de la SantePublique (Switzerland); Saint-Paul, N. [NOVAR, 75 - Paris (France); Colson, P. [Electricite de France (EDF/DPN), 93 - Saint-Denis (France); Jouve, A.; Feron, F. [Direction Generale de al Surete Nucleaire et de la Radioprotection, 75 - Paris (France); Haranger, D. [Electricite de France (EDF), 75 - Paris (France); Mathieu, P. [Institut Pasteur, 75 - Paris (France); Paycha, F. [CHU Louis Mourier, Unitede Medecine Nucleaire Assistance Publique-Hopitaux de Paris, 92 - Colombes (France); Israel, S. [CEGELEC NDT et la gestion des sources radioactives (France); Auboiroux, B. [APAVE (France); Chartier, P. [DRIRE de Basse-Normandie, Div. Surete Nucleaire et Radioprotection, 14 - Caen (France)

    2005-07-01

    Organized by the section of technical protection of the French society of radiation protection ( S.F.R.P.), these two days had for objective to review the evolution of the rule relative to the sources of ionising radiations 'sealed and unsealed radioactive sources, electric generators'. They addressed all the actors concerned by the implementation of the new regulatory system in the different sectors of activities ( research, medicine and industry): Authorities, manufacturers, and suppliers of sources, holders and users, bodies involved in the approval of sources, carriers. (N.C.)

  14. Modeling Frequency Comb Sources

    Directory of Open Access Journals (Sweden)

    Li Feng

    2016-06-01

    Full Text Available Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  15. Ion Source DECRIS-3

    CERN Document Server

    Efremov, A; Lebedev, A N; Loginov, V N; Yazvitsky, N Yu

    1999-01-01

    The ECR ion source DECRIS-3 is the copy of the mVINIS ion source which was designed and built in Dubna for the TESLA Accelerator Installation (Belgrade, Yugoslavia) in 1997. The assembly of the source was completely finished in the end of 1998 and then it was installed at the FLNR ECR test bench. The source was successfully tested with some gases and metals by using the MIVOC technique. In nearest future the source will be capable of ECR plasma heating using two different frequencies simultaneously. We are also going to use the DECRIS-3 ion source to design 1+ -> n+ technique for the DRIBs (Dubna Radioactive Ion Beams) project.

  16. 2011 NATA - Emissions Sources

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes all emissions sources that were modeled in the 2011 National Air Toxics Assessment (NATA), inlcluding point, nonpoint, and mobile sources, and...

  17. Transactional vs. Strategic Sourcing

    National Research Council Canada - National Science Library

    Mark Ware

    2010-01-01

    .... It's frequently a situation of "here's the comparator that's needed. . .find it yesterday." Having to source a comparator in a very short amount of time can impose a transactional approach to sourcing, rather than a strategic one...

  18. Sources of Gluten

    Science.gov (United States)

    ... Gluten-Free Diet › Sources of Gluten Sources of Gluten There are many food items that may contain ... gluten-free” is not specified on the label. Gluten-Containing Grains and Their Derivatives Wheat Varieties and ...

  19. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  20. Sodium and Food Sources

    Science.gov (United States)

    ... Sources Top 10 Sources of Sodium How to Reduce Sodium Sodium Reduction Resources for Everyone Sodium Reduction Fact ... in processed food [PDF-867K] and how to reduce sodium. Sodium Reduction Is Challenging Types of food matter: ...

  1. Electron Beam Ion Sources

    OpenAIRE

    Zschornacka, G.; Schmidt, M.; Thorn, A.

    2014-01-01

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviole...

  2. Open Source Business Solutions

    Directory of Open Access Journals (Sweden)

    Ion IVAN

    2008-01-01

    Full Text Available This analyses the Open source movement. Open source development process and management is seen different from the classical point of view. This focuses on characteristics and software market tendencies for the main Open source initiatives. It also points out the labor market future evolution for the software developers.

  3. Investigating Primary Source Literacy

    Science.gov (United States)

    Archer, Joanne; Hanlon, Ann M.; Levine, Jennie A.

    2009-01-01

    Primary source research requires students to acquire specialized research skills. This paper presents results from a user study testing the effectiveness of a Web guide designed to convey the concepts behind "primary source literacy". The study also evaluated students' strengths and weaknesses when conducting primary source research. (Contains 3…

  4. Noise Source Location Optimization

    Directory of Open Access Journals (Sweden)

    Ed O’Keefe

    1994-01-01

    Full Text Available This article describes a method to determine locations of noise sources that minimize modal coupling in complex acoustic volumes. Using the acoustic source scattering capabilities of the boundary element method, predictions are made of mode shape and pressure levels due to various source locations. Combining knowledge of the pressure field with a multivariable function minimization technique, the source location generating minimum pressure levels can be determined. The analysis also allows for an objective comparison of “best/worst” locations. The technique was implemented on a personal computer for the U.S. Space Station, predicting 5–10 dB noise reduction using optimum source locations.

  5. DC source assemblies

    Science.gov (United States)

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  6. Global Sourcing of Services

    DEFF Research Database (Denmark)

    Ørberg Jensen, Peter D.; Petersen, Bent

    2013-01-01

    The global sourcing of services offers high returns but is also associated with high risks. The extent to which firms engage in ‘transformational’ global sourcing (i.e., global sourcing implying considerable changes in the home organization) chiefly depends on management's comfort zone which......, in turn, is determined by managers' risk perceptions, risk tolerance, and ability to employ risk-reducing measures. Many firms move into transformational global sourcing more or less deliberately. However, as the human asset specificity of the global sourcing operation increases, managers find themselves...

  7. Markov information sources

    Science.gov (United States)

    Massey, J. L.

    1975-01-01

    A regular Markov source is defined as the output of a deterministic, but noisy, channel driven by the state sequence of a regular finite-state Markov chain. The rate of such a source is the per letter uncertainty of its digits. The well-known result that the rate of a unifilar regular Markov source is easily calculable is demonstrated, where unifilarity means that the present state of the Markov chain and the next output of the deterministic channel uniquely determine the next state. At present, there is no known method to calculate the rate of a nonunifilar source. Two tentative approaches to this unsolved problem are given, namely source identical twins and the master-slave source, which appear to shed some light on the question of rate calculation for a nonunifilar source.

  8. Markov information sources

    Science.gov (United States)

    Massey, J. L.

    1975-01-01

    A regular Markov source is defined as the output of a deterministic, but noisy, channel driven by the state sequence of a regular finite-state Markov chain. The rate of such a source is the per letter uncertainty of its digits. The well-known result that the rate of a unifilar regular Markov source is easily calculable is demonstrated, where unifilarity means that the present state of the Markov chain and the next output of the deterministic channel uniquely determine the next state. At present, there is no known method to calculate the rate of a nonunifilar source. Two tentative approaches to this unsolved problem are given, namely source identical twins and the master-slave source, which appear to shed some light on the question of rate calculation for a nonunifilar source.

  9. Neuromagnetic source reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, P.S.; Mosher, J.C. [Los Alamos National Lab., NM (United States); Leahy, R.M. [University of Southern California, Los Angeles, CA (United States)

    1994-12-31

    In neuromagnetic source reconstruction, a functional map of neural activity is constructed from noninvasive magnetoencephalographic (MEG) measurements. The overall reconstruction problem is under-determined, so some form of source modeling must be applied. We review the two main classes of reconstruction techniques-parametric current dipole models and nonparametric distributed source reconstructions. Current dipole reconstructions use a physically plausible source model, but are limited to cases in which the neural currents are expected to be highly sparse and localized. Distributed source reconstructions can be applied to a wider variety of cases, but must incorporate an implicit source, model in order to arrive at a single reconstruction. We examine distributed source reconstruction in a Bayesian framework to highlight the implicit nonphysical Gaussian assumptions of minimum norm based reconstruction algorithms. We conclude with a brief discussion of alternative non-Gaussian approachs.

  10. Wavelength sweepable laser source

    DEFF Research Database (Denmark)

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  11. Neuromagnetic source reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, P.S.; Mosher, J.C. [Los Alamos National Lab., NM (United States); Leahy, R.M. [University of Southern California, Los Angeles, CA (United States)

    1994-12-31

    In neuromagnetic source reconstruction, a functional map of neural activity is constructed from noninvasive magnetoencephalographic (MEG) measurements. The overall reconstruction problem is under-determined, so some form of source modeling must be applied. We review the two main classes of reconstruction techniques-parametric current dipole models and nonparametric distributed source reconstructions. Current dipole reconstructions use a physically plausible source model, but are limited to cases in which the neural currents are expected to be highly sparse and localized. Distributed source reconstructions can be applied to a wider variety of cases, but must incorporate an implicit source, model in order to arrive at a single reconstruction. We examine distributed source reconstruction in a Bayesian framework to highlight the implicit nonphysical Gaussian assumptions of minimum norm based reconstruction algorithms. We conclude with a brief discussion of alternative non-Gaussian approachs.

  12. Global Sourcing Flexibility

    DEFF Research Database (Denmark)

    Ørberg Jensen, Peter D.; Petersen, Bent

    2013-01-01

    sourcing flexibility. Here we draw on prior research in the fields of organizational flexibility, international business and global sourcing as well as case examples and secondary studies. In the second part of the paper, we discuss the implications of global sourcing flexibility for firm strategy......Recent studies show that flexibility is a key concern for firms that engage in the global sourcing of services. In this conceptual paper, we seek to explore two central aspects of global sourcing flexibility: In the first part of the paper, we provide a definition of the construct of global...... and operations against the backdrop of the theory-based definition of the construct. We discuss in particular the importance of global sourcing flexibility for operational performance stability, and the trade-off between specialization benefits, emerging from location and service provider specialization, versus...

  13. Soldier System Power Sources

    Science.gov (United States)

    2006-12-31

    squad level, with the fundamental goal of reducing the total mass of the electric power sources carried by a Marine in the Expeditionary Forces while...still meeting all of his electric power demands. To achieve that goal, this work investigated the effectiveness of hybrid power sources composed...variously of batteries, fuel cells, and super capacitors, it developed control algorithms for those hybrid power sources , it assessed the value of

  14. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  15. Lithium ion sources

    Science.gov (United States)

    Roy, Prabir K.; Greenway, Wayne G.; Grote, Dave P.; Kwan, Joe W.; Lidia, Steven M.; Seidl, Peter A.; Waldron, William L.

    2014-01-01

    A 10.9 cm diameter lithium alumino-silicate ion source has been chosen as a source of ˜100mA lithium ion current for the Neutralized Drift Compression Experiment (NDCX-II) at LBNL. Research and development was carried out on lithium alumino-silicate ion sources prior to NDCX-II source fabrication. Space-charge-limited emission with the current density exceeding 1 mA/cm2 was measured with 0.64 cm diameter lithium alumino-silicate ion sources at 1275 °C. The beam current density is less for the first 10.9 cm diameter NDCX-II source, and it may be due to an issue of surface coverage. The lifetime of a thin coated (on a tungsten substrate) source is varied, roughly 40-50 h, when pulsed at 0.05 Hz and with pulse length of 6μs each, i.e., a duty factor of 3×10-7, at an operating temperature of 1250-1275 °C. The 10.9 cm diameter source lifetime is likely the same as of a 0.64 cm source, but the lifetime of a source with a 2 mm diameter (without a tungsten substrate) is 10-15 h with a duty factor of 1 (DC extraction). The lifetime variation is dependent on the amount of deposition of β-eucryptite mass, and the surface temperature. The amount of mass deposition does not significantly alter the current density. More ion source work is needed to improve the large source performance.

  16. Lithium ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Prabir K., E-mail: pkroy@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), One Cyclotron Road, Berkeley, California CA-94720 (United States); Greenway, Wayne G. [Lawrence Berkeley National Laboratory (LBNL), One Cyclotron Road, Berkeley, California CA-94720 (United States); Grote, Dave P. [Lawrence Livermore National Laboratory LLC, CA-94550 (United States); Kwan, Joe W.; Lidia, Steven M.; Seidl, Peter A.; Waldron, William L. [Lawrence Berkeley National Laboratory (LBNL), One Cyclotron Road, Berkeley, California CA-94720 (United States)

    2014-01-01

    A 10.9 cm diameter lithium alumino-silicate ion source has been chosen as a source of ∼100mA lithium ion current for the Neutralized Drift Compression Experiment (NDCX-II) at LBNL. Research and development was carried out on lithium alumino-silicate ion sources prior to NDCX-II source fabrication. Space-charge-limited emission with the current density exceeding 1 mA/cm{sup 2} was measured with 0.64 cm diameter lithium alumino-silicate ion sources at 1275 °C. The beam current density is less for the first 10.9 cm diameter NDCX-II source, and it may be due to an issue of surface coverage. The lifetime of a thin coated (on a tungsten substrate) source is varied, roughly 40–50 h, when pulsed at 0.05 Hz and with pulse length of 6μs each, i.e., a duty factor of 3×10{sup −7}, at an operating temperature of 1250–1275 °C. The 10.9 cm diameter source lifetime is likely the same as of a 0.64 cm source, but the lifetime of a source with a 2 mm diameter (without a tungsten substrate) is 10–15 h with a duty factor of 1 (DC extraction). The lifetime variation is dependent on the amount of deposition of β-eucryptite mass, and the surface temperature. The amount of mass deposition does not significantly alter the current density. More ion source work is needed to improve the large source performance.

  17. Source tree composition

    OpenAIRE

    Jonge, de, H.J.

    2002-01-01

    Dividing software systems in components improves software reusability as well as software maintainability. Components live at several levels, we concentrate on the implementation level where components are formed by source files, divided over directory structures. Such source code components are usually strongly coupled in the directory structure of a software system. Their compilation is usually controlled by a single global build process. This entangling of source trees and build processes ...

  18. Source and replica calculations

    Energy Technology Data Exchange (ETDEWEB)

    Whalen, P.P.

    1994-02-01

    The starting point of the Hiroshima-Nagasaki Dose Reevaluation Program is the energy and directional distributions of the prompt neutron and gamma-ray radiation emitted from the exploding bombs. A brief introduction to the neutron source calculations is presented. The development of our current understanding of the source problem is outlined. It is recommended that adjoint calculations be used to modify source spectra to resolve the neutron discrepancy problem.

  19. Acoustic emission source modeling

    Directory of Open Access Journals (Sweden)

    Hora P.

    2010-07-01

    Full Text Available The paper deals with the acoustic emission (AE source modeling by means of FEM system COMSOL Multiphysics. The following types of sources are used: the spatially concentrated force and the double forces (dipole. The pulse excitation is studied in both cases. As a material is used steel. The computed displacements are compared with the exact analytical solution of point sources under consideration.

  20. Source SDK development essentials

    CERN Document Server

    Bernier, Brett

    2014-01-01

    The Source Authoring Tools are the pieces of software used to create custom content for games made with Valve's Source engine. Creating mods and maps for your games without any programming knowledge can be time consuming. These tools allow you to create your own maps and levels without the need for any coding knowledge. All the tools that you need to start creating your own levels are built-in and ready to go! This book will teach you how to use the Authoring Tools provided with Source games and will guide you in creating your first maps and mods (modifications) using Source. You will learn ho

  1. Advanced Photon Source (APS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratoryprovides this nation's (in fact, this hemisphere's) brightest storage...

  2. Fifth generation light sources

    Science.gov (United States)

    Romaniuk, Ryszard S.

    2016-12-01

    Coherent light sources are one of the most fundamental research tools in biology, technology and in other areas. Synchrotron light source consists of a few basic parts: energy source - which is an electron beam accelerator, energy converter between electron and photon beams - which is an undulator, and photon user experimental lines. Each of these parts is separately a complex system, which is currently a subject to fast technological development. Future light sources of the fifth generation are based on completely new solutions of these fundamental parts, in comparison with the sources of the previous generations. Energy source is a new generation laser - plasma accelerator with electrical field in the area of multiple GV/m. A miniature undulator is tested in the MEMS technology from new materials. Classical light beam lines, vacuum, and difficult for management and beam distribution, change their meaning in the case of availability of miniature undulators positioned immediately at or even inside the experimental stations. After an introduction concerning the light sources of the previous generations, the article shows current research efforts on the mentioned key components of the fifth generation light sources. In some cases this is a continuation and modernization of the previous technologies, in the majority it is a brave endeavour to apply completely new technologies, like laser - plasma acceleration.

  3. Variability in GPS sources

    NARCIS (Netherlands)

    Jauncey, DL; King, EA; Bignall, HE; Lovell, JEJ; Kedziora-Chudczer, L; Tzioumis, AK; Tingay, SJ; Macquart, JP; McCulloch, PM

    2003-01-01

    Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, similar to10%, vary. Their variability falls

  4. Militarized Thermoelectric Power Sources.

    Science.gov (United States)

    1979-07-01

    Thermoelectric power sources are being developed to provide multifuel, silent, maintenance free tactical power generators for forward area...applications. Recent technology improvements, state of development, and performance characteristics of the 100-Watt and 500-Watt Thermoelectric Power Sources are presented. (Author)

  5. Using Primary Source Documents.

    Science.gov (United States)

    Mintz, Steven

    2003-01-01

    Explores the use of primary sources when teaching about U.S. slavery. Includes primary sources from the Gilder Lehrman Documents Collection (New York Historical Society) to teach about the role of slaves in the Revolutionary War, such as a proclamation from Lord Dunmore offering freedom to slaves who joined his army. (CMK)

  6. Creating Open Source Conversation

    Science.gov (United States)

    Sheehan, Kate

    2009-01-01

    Darien Library, where the author serves as head of knowledge and learning services, launched a new website on September 1, 2008. The website is built with Drupal, an open source content management system (CMS). In this article, the author describes how she and her colleagues overhauled the library's website to provide an open source content…

  7. Open source community organization

    CSIR Research Space (South Africa)

    Molefe, Onkgopotse M

    2009-05-01

    Full Text Available Open Source communities (OSCs), sometimes referred to as virtual or online communities play a significant role in terms of the contribution they continue to make in producing user-friendly Open Source Software (OSS) solutions. Many projects have...

  8. Using Primary Source Documents.

    Science.gov (United States)

    Mintz, Steven

    2003-01-01

    Explores the use of primary sources when teaching about U.S. slavery. Includes primary sources from the Gilder Lehrman Documents Collection (New York Historical Society) to teach about the role of slaves in the Revolutionary War, such as a proclamation from Lord Dunmore offering freedom to slaves who joined his army. (CMK)

  9. PORTABLE SOURCE OF RADIOACTIVITY

    Science.gov (United States)

    Goertz, R.C.; Ferguson, K.R.; Rylander, E.W.; Safranski, L.M.

    1959-06-16

    A portable source for radiogiaphy or radiotherapy is described. It consists of a Tl/sup 170/ or Co/sup 60/ source mounted in a rotatable tungsten alloy plug. The plug rotates within a brass body to positions of safety or exposure. Provision is made for reloading and carrying the device safely. (T.R.H.)

  10. Source tree composition

    NARCIS (Netherlands)

    Jonge, M. de

    2002-01-01

    Dividing software systems in components improves software reusability as well as software maintainability. Components live at several levels, we concentrate on the implementation level where components are formed by source files, divided over directory structures. Such source code components are usu

  11. The Chandra Source Catalog

    CERN Document Server

    Evans, Ian N; Glotfelty, Kenny J; Anderson, Craig S; Bonaventura, Nina R; Chen, Judy C; Davis, John E; Doe, Stephen M; Evans, Janet D; Fabbiano, Giuseppina; Galle, Elizabeth C; Gibbs, Danny G; Grier, John D; Hain, Roger M; Hall, Diane M; Harbo, Peter N; Xiangqun,; He,; Houck, John C; Karovska, Margarita; Kashyap, Vinay L; Lauer, Jennifer; McCollough, Michael L; McDowell, Jonathan C; Miller, Joseph B; Mitschang, Arik W; Morgan, Douglas L; Mossman, Amy E; Nichols, Joy S; Nowak, Michael A; Plummer, David A; Refsdal, Brian L; Rots, Arnold H; Siemiginowska, Aneta; Sundheim, Beth A; Tibbetts, Michael S; Van Stone, David W; Winkelman, Sherry L; Zografou, Panagoula

    2010-01-01

    The Chandra Source Catalog (CSC) is a general purpose virtual X-ray astrophysics facility that provides access to a carefully selected set of generally useful quantities for individual X-ray sources, and is designed to satisfy the needs of a broad-based group of scientists, including those who may be less familiar with astronomical data analysis in the X-ray regime. The first release of the CSC includes information about 94,676 distinct X-ray sources detected in a subset of public ACIS imaging observations from roughly the first eight years of the Chandra mission. This release of the catalog includes point and compact sources with observed spatial extents <~ 30''. The catalog (1) provides access to the best estimates of the X-ray source properties for detected sources, with good scientific fidelity, and directly supports scientific analysis using the individual source data; (2) facilitates analysis of a wide range of statistical properties for classes of X-ray sources; and (3) provides efficient access to ...

  12. Radiation Source Replacement Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, Jeffrey W.; Moran, Traci L.; Bond, Leonard J.

    2010-12-01

    This report summarizes a Radiation Source Replacement Workshop in Houston Texas on October 27-28, 2010, which provided a forum for industry and researchers to exchange information and to discuss the issues relating to replacement of AmBe, and potentially other isotope sources used in well logging.

  13. Variability in GPS sources

    NARCIS (Netherlands)

    Jauncey, DL; King, EA; Bignall, HE; Lovell, JEJ; Kedziora-Chudczer, L; Tzioumis, AK; Tingay, SJ; Macquart, JP; McCulloch, PM

    2003-01-01

    Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, similar to10%, vary. Their variability falls

  14. Radioactive Sources Service

    CERN Multimedia

    2007-01-01

    Please note that the radioactive sources service will be open by appointment only every Monday, Wednesday and Friday during CERN working hours (instead of alternate weeks). In addition, please note that our 2007 schedule is available on our web site: http://cern.ch/service-rp-sources

  15. Radioactive Sources Service

    CERN Multimedia

    2007-01-01

    Please note that the radioactive sources service will be open by appointment only every Monday, Wednesday and Friday during CERN working hours (instead of alternate weeks). In addition, please note that our 2007 schedule is available on our web site. http://cern.ch/service-rp-sources

  16. Creating Open Source Conversation

    Science.gov (United States)

    Sheehan, Kate

    2009-01-01

    Darien Library, where the author serves as head of knowledge and learning services, launched a new website on September 1, 2008. The website is built with Drupal, an open source content management system (CMS). In this article, the author describes how she and her colleagues overhauled the library's website to provide an open source content…

  17. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  18. Nonlinear Source Emulator

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem

    and remains the prime source of energy in non-terrestrial applications such as those in sky-explorers. However, a renewable energy source is expensive, bulky, and its performance is weather dependent, which make testing of downstream converters very difficult. As a result, a nonlinear source emulator (NSE......) is a good solution to solve the problems associated with the use of real nonlinear sources in testing phases. However, a recent technical survey conducted during this work shows that most existing NSEs have only been concerned with simulating nonlinear systems in terrestrial applications. Furthermore......, their dynamic performance were not fast enough in order to imitate how a real nonlinear energy source would react under extreme conditions and operation modes. Particularly, a system in the sky can experience a step change of sunlight irradiation. Moreover, operation modes may include load step between nominal...

  19. Peristaltic ion source

    Energy Technology Data Exchange (ETDEWEB)

    Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.

    1995-08-01

    Conventional ion sources generate energetic ion beams by accelerating the plasma-produced ions through a voltage drop at the extractor, and since it is usual that the ion beam is to propagate in a space which is at ground potential, the plasma source is biased at extractor voltage. For high ion beam energy the plasma source and electrical systems need to be raised to high voltage, a task that adds considerable complexity and expense to the total ion source system. The authors have developed a system which though forming energetic ion beams at ground potential as usual, operates with the plasma source and electronics at ground potential also. Plasma produced by a nearby source streams into a grided chamber that is repetitively pulsed from ground to high positive potential, sequentially accepting plasma into its interior region and ejecting it energetically. They call the device a peristaltic ion source. In preliminary tests they`ve produced nitrogen and titanium ion beams at energies from 1 to 40 keV. Here they describe the philosophy behind the approach, the test embodiment that they have made, and some preliminary results.

  20. Advanced positron sources

    Energy Technology Data Exchange (ETDEWEB)

    Variola, A., E-mail: variola@lal.in2p3.fr

    2014-03-11

    Positron sources are a critical system for the future lepton colliders projects. Due to the large beam emittance at the production and the limitation given by the target heating and mechanical stress, the main collider parameters fixing the luminosity are constrained by the e{sup +} sources. In this context also the damping ring design boundary conditions and the final performance are given by the injected positron beam. At present different schemes are being taken into account in order to increase the production and the capture yield of the positron sources, to reduce the impact of the deposited energy in the converter target and to increase the injection efficiency in the damping ring. The final results have a strong impact not only on the collider performance but also on its cost optimization. After a short introduction illustrating their fundamental role, the basic positron source scheme and the performance of the existing sources will be illustrated. The main innovative designs for the future colliders advanced sources will be reviewed and the different developed technologies presented. Finally the positrons-plasma R and D experiments and the futuristic proposals for positron sources will reviewed.

  1. Microwave Discharge Ion Sources

    CERN Document Server

    Celona, L

    2013-01-01

    This chapter describes the basic principles, design features and characteristics of microwave discharge ion sources. A suitable source for the production of intense beams for high-power accelerators must satisfy the requirements of high brightness, stability and reliability. The 2.45 GHz off-resonance microwave discharge sources are ideal devices to generate the required beams, as they produce multimilliampere beams of protons, deuterons and singly charged ions. A description of different technical designs will be given, analysing their performance, with particular attention being paid to the quality of the beam, especially in terms of its emittance.

  2. Nuclear electric power sources

    Science.gov (United States)

    Singh, J. J.

    1978-01-01

    Measurements on radioactive commercial p-n junction silicon cells show that these units are capable of delivering several hundred microwatts per curie of Am-241 alpha source, indicating their usefulness in such electronic devices as hearing aids, heart pacemakers, electronic watches, delay timers and nuclear dosimeter chargers. It is concluded that the Am-241 sources are superior to the beta sources used previously, because of higher alpha specific ionization and simultaneous production of low energy photons which are easily converted into photoelectrons for additional power.

  3. Characterizing Entanglement Sources

    CERN Document Server

    Lougovski, Pavel

    2009-01-01

    We discuss how to characterize entanglement sources with finite sets of measurements. The measurements do not have to be tomographically complete, and may consist of POVMs rather than von Neumann measurements. Our method yields a probability that the source generates an entangled state as well as estimates of any desired calculable entanglement measures, including their error bars. We apply two criteria, namely Akaike's information criterion and the Bayesian information criterion, to compare and assess different models (with different numbers of parameters) describing entanglement-generating devices. We discuss differences between standard entanglement-verificaton methods and our present method of characterizing an entanglement source.

  4. Thermoelectricity Light Sources

    Institute of Scientific and Technical Information of China (English)

    SHIYongji

    1997-01-01

    A thermoelectricity light source in a gaseous plasma discharge between two electrodes is described,one of which emits electrons thermoionically.The analytical model describing basic physical phenomena is developed.The results are excellent agreement with simulated test.

  5. EPA Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Information on sole source aquifers (SSAs) is widely used in assessments under the National Environmental Policy Act and at the state and local level. A national...

  6. Nonpoint Source: Agriculture

    Science.gov (United States)

    Agricultural runoff as a nonpoint source category of pollution. Resouces to learn more a bout conservation practices to reduce water quality impacts from storm water run off and ground water infiltration

  7. Public Water Sources

    Data.gov (United States)

    Vermont Center for Geographic Information — This GIS layer consists of the geographic location of active and inactive public (Community, non-transient non-community and transient non-community) water sources...

  8. Alternative fuel information sources

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This short document contains a list of more than 200 US sources of information (Name, address, phone number, and sometimes contact) related to the use of alternative fuels in automobiles and trucks. Electric-powered cars are also included.

  9. Casimir light: the source.

    OpenAIRE

    1993-01-01

    The release of Casimir energy in filling a dielectric hole is identified as the source of coherent sonoluminescence. Qualitative agreement with recently acquired data is found for the magnitude and shape of the spectrum.

  10. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  11. Advanced Light Source (ALS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Light Source (ALS), a world leader in soft x-ray science, generates light in the wavelengths needed for examining the atomic and electronic structure of...

  12. Environmental Data Sources

    Data.gov (United States)

    Kansas Data Access and Support Center — This database includes gauging stations, climatic data centers, and storet sites. The accuracy of the locations is dependent on the source data for each of the...

  13. Field emission electron source

    Science.gov (United States)

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  14. Diversification of energy sources

    Science.gov (United States)

    1975-01-01

    The concept of energy source diversification was introduced as a substitution conservation action. The current status and philosophy behind a diversification program is presented in the context of a national energy policy. Advantages, disadvantages (constraints), and methods of implementation for diversification are discussed. The energy source systems for diversification are listed and an example impact assessment is outlined which deals with the water requirements of the specific energy systems.

  15. Cardiomagnetic source imaging

    OpenAIRE

    Pesola, Katja

    2000-01-01

    Magnetocardiographic (MCG) source imaging has received increasing interest in recent years. With a high enough localization accuracy of the current sources in the heart, valuable information can be provided, e.g., for the pre-ablative evaluation of arrhythmia patients. Furthermore, preliminary studies indicate that ischemic areas, i.e. areas which are suffering from lack of oxygen, and infarcted regions could be localized from multichannel MCG recordings. In this thesis, the accuracy of cardi...

  16. Nonpoint Source Pollution.

    Science.gov (United States)

    Mccoy, Nicholas; Chao, Bing; Gang, Daniel Dianchen

    2015-10-01

    The article presents a comprehensive review of research advancing in 2014 on nonpoint source pollution (NPS). The topics presented relate to nonpoint source pollution (NPS) within agricultural and urban areas. NPS pollution from agricultural areas is the main focus in this review. Management of NPS in agricultural, urban and rural areas is presented. Modeling of NPS pollution in different watersheds with various modeling tools is reviewed.

  17. Radio frequency ion source

    CERN Document Server

    Shen Guan Ren; Gao Fu; LiuNaiYi

    2001-01-01

    The study on Radio Frequency Ion Source is mainly introduced, which is used for CIAE 600kV ns Pulse Neutron Generator; and obtained result is also presented. The RF ion source consists of a diameter phi 25 mm, length 200 mm, coefficient of expansion =3.5 mA, beam current on target >=1.5 mA, beam spot =100 h.

  18. Open source molecular modeling.

    Science.gov (United States)

    Pirhadi, Somayeh; Sunseri, Jocelyn; Koes, David Ryan

    2016-09-01

    The success of molecular modeling and computational chemistry efforts are, by definition, dependent on quality software applications. Open source software development provides many advantages to users of modeling applications, not the least of which is that the software is free and completely extendable. In this review we categorize, enumerate, and describe available open source software packages for molecular modeling and computational chemistry. An updated online version of this catalog can be found at https://opensourcemolecularmodeling.github.io.

  19. Magnetron sputtering source

    Science.gov (United States)

    Makowiecki, Daniel M.; McKernan, Mark A.; Grabner, R. Fred; Ramsey, Philip B.

    1994-01-01

    A magnetron sputtering source for sputtering coating substrates includes a high thermal conductivity electrically insulating ceramic and magnetically attached sputter target which can eliminate vacuum sealing and direct fluid cooling of the cathode assembly. The magnetron sputtering source design results in greater compactness, improved operating characteristics, greater versatility, and low fabrication cost. The design easily retrofits most sputtering apparatuses and provides for safe, easy, and cost effective target replacement, installation, and removal.

  20. Diversification of energy sources

    Science.gov (United States)

    1975-01-01

    The concept of energy source diversification was introduced as a substitution conservation action. The current status and philosophy behind a diversification program is presented in the context of a national energy policy. Advantages, disadvantages (constraints), and methods of implementation for diversification are discussed. The energy source systems for diversification are listed and an example impact assessment is outlined which deals with the water requirements of the specific energy systems.

  1. Radio source evolution

    CERN Document Server

    Perucho, Manel

    2015-01-01

    Baldwin (1982) wrote that "the distribution of sources in the radio luminosity, P, overall physical size, D, diagram" could be considered as "the radio astronomer's H-R diagram". However, unlike the case of stars, not only the intrinsic properties of the jets, but also those of the host galaxy and the intergalactic medium are relevant to explain the evolutionary tracks of radio radio sources. In this contribution I review the current status of our understanding of the evolution of radio sources from a theoretical and numerical perspective, using the P-D diagram as a framework. An excess of compact (linear size < 10 kpc) sources could be explained by low-power jets being decelerated within the host galaxy, as shown by recent numerical simulations. These decelerated jets could also explain the population of the radio sources that have been recently classified as FR0. I will discuss the possible tracks that radio sources may follow within this diagram, and some of the physical processes that can explain the d...

  2. Deep source gas

    Energy Technology Data Exchange (ETDEWEB)

    1985-02-01

    Three separate emplacement concepts could explain the occurrence of gas at extreme depths: abiogenesis (a primordial, nonbiologic origin source); subducted, organic-origin gas (involving the deep, tectonic subduction emplacement of hydrocarbon-generating ocean sediments); and deep sedimentary basin gas (the more conventional emplacement of sedimentary rocks by deep downwarping of the Earth's crust). Of these concepts, Deep Source Gas research focuses on the subducted, organic-origin concept. The purpose of Deep Source Gas research is to verify natural gas arising from depths in excess of 30,000 feet, to relate these occurrences to conceptual models, to define the limits of target areas, to quantify the resource, and to determine the significance of the gas to the nation's reserves. The research emphasizes an Earth science study (geology, geochemistry, and geophysics) of the Cordilleran Geologic Province of western North America. This area is considered a prospective source largely because of known and suspected plate tectonic structures and their youthful emplacement, which increase the likelihood of a timely entrapment of deep-source generated hydrocarbons. Detailed geochemical studies indicate that the deep-source-gas generating capacity of the Aleutian Trench area of southern Alaska is high. Furthermore, geophysical studies show that an apparent fossil subduction zone exists in western Washington. This zone appears to have very thick sedimentary rock units, the existence of which will be evaluated through a more detailed seismic study and possibly through drilling activities. Structural observations made in the northern Brooks Range and central Alaskan Range indicate that overthrusting and compressional features may serve as large-scale target areas for deep source gas generation and occurrence. 12 figures, 2 tables.

  3. Characteristics and locations of sources

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, J.; Poellaenen, R.; Toivonen, H. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1997-12-31

    Ten artificial radiation sources were placed in the terrain in order to test the capability of airborne measuring teams to detect them. One of the sources was a line source, others were point sources (three of them collimated). The radionuclides used in the sources were {sup 60}Co, {sup 137}Cs, {sup 99m}Tc and {sup 192}Ir. The source activities ranged from about 26 MBq (one of the cobalt sources) to 0.56 TBq (iridium). (au).

  4. Open Source Telecommunication Companies

    Directory of Open Access Journals (Sweden)

    Peter Liu

    2007-08-01

    Full Text Available Little is known about companies whose core business is selling telecommunications products that lever open source projects. Open source telecommunications (OST companies operate in markets that are very different from typical software product markets. The telecommunications market is regulated, vertically integrated, and proprietary designs and special chips are widely used. For a telecommunications product to be useful, it must interact with both access network products and core network products. Due to specifications in Service Agreements Levels, penalties for failures of telecommunications products are very high. This article shares information that is not widely known, including a list of OST companies and the open source projects on which they depend, the size and diversity of venture capital investment in OST companies, the nature of the commercial product-open source software and company-project relationships, ways in which OST companies make money, benefits and risks of OST companies, and competition between OST companies. Analysis of this information provides insights into the ways in which companies can build business models around open source software. These findings will be of interest to entrepreneurs, top management teams of incumbent companies that sell telecommunications products, and those who care about Ontario's ability to compete globally.

  5. Open source posturography.

    Science.gov (United States)

    Rey-Martinez, Jorge; Pérez-Fernández, Nicolás

    2016-12-01

    The proposed validation goal of 0.9 in intra-class correlation coefficient was reached with the results of this study. With the obtained results we consider that the developed software (RombergLab) is a validated balance assessment software. The reliability of this software is dependent of the used force platform technical specifications. Develop and validate a posturography software and share its source code in open source terms. Prospective non-randomized validation study: 20 consecutive adults underwent two balance assessment tests, six condition posturography was performed using a clinical approved software and force platform and the same conditions were measured using the new developed open source software using a low cost force platform. Intra-class correlation index of the sway area obtained from the center of pressure variations in both devices for the six conditions was the main variable used for validation. Excellent concordance between RombergLab and clinical approved force platform was obtained (intra-class correlation coefficient =0.94). A Bland and Altman graphic concordance plot was also obtained. The source code used to develop RombergLab was published in open source terms.

  6. Optical source transformations.

    Science.gov (United States)

    Kundtz, N; Roberts, D A; Allen, J; Cummer, S; Smith, D R

    2008-12-22

    Transformation optics is a recently appreciated methodology for the design of complex media that control the propagation of electromagnetic and other types of waves. The transformation optical technique involves the use of coordinate transformations applied to some region of space, providing a conceptual means to redirect the flow of waves. Successfully designed devices to date have made use of transformations acting on passive space only; however, the technique can also be applied when source distributions (e.g., current and charge) are included within the space being transformed. In this paper we present examples of source transformations that illustrate the potential of these expanded transformation optical methods. In particular, using finite-element full-wave simulations, we confirm the restoration of dipole radiation patterns from both a distorted 'pin-wheel' antenna and a bent dipole partially occluded by a cylindrical scatterer. We propose the technique of source transformations as a powerful approach for antenna design, especially in relation to conformal antennas.

  7. Studies on seismic source

    Institute of Scientific and Technical Information of China (English)

    李世愚; 陈运泰

    2003-01-01

    During the period of 1999~2002, the Chinese seismologists made a serious of developments in the study on seismic sources including observations, experiments and theory. In the field of observation, the methods of the accuracy location of earthquake sources, the inversion of seismic moment tensor and the mechanism of earthquake source are improved and developed. A lot of important earthquake events are studied by using these methods. The rupture processes of these events are inverted and investigated combined with the local stress fields and the tectonic moment by using the measurements of surface deformation. In the fields of experiments and theory, many developments are obtained in cause of seismic formation, condition of stress and tectonics, dynamics of earthquake rupture, rock fracture and nucleation of strong earthquakes.

  8. Astrophysics Source Code Library

    CERN Document Server

    Allen, Alice; Berriman, Bruce; Hanisch, Robert J; Mink, Jessica; Teuben, Peter J

    2012-01-01

    The Astrophysics Source Code Library (ASCL), founded in 1999, is a free on-line registry for source codes of interest to astronomers and astrophysicists. The library is housed on the discussion forum for Astronomy Picture of the Day (APOD) and can be accessed at http://ascl.net. The ASCL has a comprehensive listing that covers a significant number of the astrophysics source codes used to generate results published in or submitted to refereed journals and continues to grow. The ASCL currently has entries for over 500 codes; its records are citable and are indexed by ADS. The editors of the ASCL and members of its Advisory Committee were on hand at a demonstration table in the ADASS poster room to present the ASCL, accept code submissions, show how the ASCL is starting to be used by the astrophysics community, and take questions on and suggestions for improving the resource.

  9. INEEL Source Water Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Sehlke, Gerald

    2003-03-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) covers approximately 890 mi2 and includes 12 public water systems that must be evaluated for Source water protection purposes under the Safe Drinking Water Act. Because of its size and location, six watersheds and five aquifers could potentially affect the INEEL’s drinking water sources. Based on a preliminary evaluation of the available information, it was determined that the Big Lost River, Birch Creek, and Little Lost River Watersheds and the eastern Snake River Plain Aquifer needed to be assessed. These watersheds were delineated using the United States Geologic Survey’s Hydrological Unit scheme. Well capture zones were originally estimated using the RESSQC module of the Environmental Protection Agency’s Well Head Protection Area model, and the initial modeling assumptions and results were checked by running several scenarios using Modflow modeling. After a technical review, the resulting capture zones were expanded to account for the uncertainties associated with changing groundwater flow directions, a thick vadose zone, and other data uncertainties. Finally, all well capture zones at a given facility were merged to a single wellhead protection area at each facility. A contaminant source inventory was conducted, and the results were integrated with the well capture zones, watershed and aquifer information, and facility information using geographic information system technology to complete the INEEL’s Source Water Assessment. Of the INEEL’s 12 public water systems, three systems rated as low susceptibility (EBR-I, Main Gate, and Gun Range), and the remainder rated as moderate susceptibility. No INEEL public water system rated as high susceptibility. We are using this information to develop a source water management plan from which we will subsequently implement an INEEL-wide source water management program. The results are a very robust set of wellhead protection areas that will

  10. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  11. Sources of Financial Sociability

    DEFF Research Database (Denmark)

    Thompson, Grahame

    2011-01-01

    This article investigates the sources of sociability in modern financial systems as a prelude to assessing the prospects for financial regulation. Three sources are identified: sociality dependent upon contract, upon relational interdependency, and upon the operation of will and passion. Each...... of the article which is to explore further the nature of ‘irrationality’ as manifest in financial crises. When the contours of both these aspects of financial calculation have been elaborated, the article moves on to consider how they might shape regulatory responses to the seeming inevitability of financial...

  12. Valorization of ECR sources

    CERN Document Server

    2003-01-01

    One way to limit the size of particle accelerators is to use intense multicharged ion beams. Thus, compact, low cost and reliable sources have been developed. These sources are based on the electron cyclotron resonance (ECR) principle and need no cathode nor filament. A prototype named Nanogan has been developed for the Spiral project of the Ganil accelerator (Caen, France). Then, this technology has been transferred toward other research domains and industrial applications, like the ion implantation in micro-electronics components. (J.S.)

  13. Hahmosuunnittelu Source Engine -pelimoottorille

    OpenAIRE

    Korpilaakso, Joonas

    2010-01-01

    Tämän opinnäytetyön tarkoitus oli tutkia videopelien hahmosuunnittelua nykypäivänä ja selvittää mitä eri työvaiheita hahmosuunnittelu pitää sisällään sekä suunnitella ja toteuttaa pelihahmo Source Engine-pelimoottorille. Tutkimusten pohjalta suunniteltiin pelihahmo Valve Softwaren kehittämälle Source Engine-pelimoottorille. Hahmo suunniteltiin Half-Life 2-pelin modifikaatioon ”The Keep”, jonka tarinan ympärille hahmo rakennettiin. Työn tavoitteena oli suunnitella ja toteuttaa pelihahmo, joka ...

  14. OLED area illumination source

    Science.gov (United States)

    Foust, Donald Franklin; Duggal, Anil Raj; Shiang, Joseph John; Nealon, William Francis; Bortscheller, Jacob Charles

    2008-03-25

    The present invention relates to an area illumination light source comprising a plurality of individual OLED panels. The individual OLED panels are configured in a physically modular fashion. Each OLED panel comprising a plurality of OLED devices. Each OLED panel comprises a first electrode and a second electrode such that the power being supplied to each individual OLED panel may be varied independently. A power supply unit capable of delivering varying levels of voltage simultaneously to the first and second electrodes of each of the individual OLED panels is also provided. The area illumination light source also comprises a mount within which the OLED panels are arrayed.

  15. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk

    2017-01-01

    winter and spring explained by expansion of the polar dome enabling long-range transport of aerosols from source regions outside the Arctic. This phenomenon is better known as the Arctic haze. Contrary, the summer and fall concentrations were lower due to the retreat of the polar dome. These seasonal...... species. The aerosol concentration decreased during spring as the Arctic haze leveled off. A source apportionment analysis showed that three factors were contributing to organic aerosols. A hydrocarbon-like organic aerosol factor was assigned to fossil fuel combustion and a second factor, less oxygenated...

  16. Open Source Software Acquisition

    DEFF Research Database (Denmark)

    Holck, Jesper; Kühn Pedersen, Mogens; Holm Larsen, Michael

    2005-01-01

    Lately we have seen a growing interest from both public and private organisations to adopt OpenSource Software (OSS), not only for a few, specific applications but also on a more general levelthroughout the organisation. As a consequence, the organisations' decisions on adoption of OSS arebecoming...

  17. Information sources [Chapter 12

    Science.gov (United States)

    Daniel G. Neary; John N. Rinne; Alvin L. Medina

    2012-01-01

    The main information sources for the UVR consist of several web sites with general information and bibliographies. RMRS has publications on its Air, Water, Aquatic Environments (AWAE) Program Flagstaff web site. Another RMRS and University of Arizona website on semi-arid and arid watersheds contains a large, searchable bibliography of supporting information from the...

  18. Open source development

    DEFF Research Database (Denmark)

    Ulhøi, John Parm

    2004-01-01

    This paper addresses innovations based on open source or non-proprietary knowledge. Viewed through the lens of private property theory, such agency appears to be a true anomaly. However, by a further turn of the theoretical kaleidoscope, we will show that there may be perfectly justifiable reason...

  19. Alternative Energy Sources

    CERN Document Server

    Michaelides, Efstathios E (Stathis)

    2012-01-01

    Alternative Energy Sources is designed to give the reader, a clear view of the role each form of alternative energy may play in supplying the energy needs of the human society in the near and intermediate future (20-50 years).   The two first chapters on energy demand and supply and environmental effects, set the tone as to why the widespread use of alternative energy is essential for the future of human society. The third chapter exposes the reader to the laws of energy conversion processes, as well as the limitations of converting one energy form to another. The sections on exergy give a succinct, quantitative background on the capability/potential of each energy source to produce power on a global scale. The fourth, fifth and sixth chapters are expositions of fission and fusion nuclear energy. The following five chapters (seventh to eleventh) include detailed descriptions of the most common renewable energy sources – wind, solar, geothermal, biomass, hydroelectric – and some of the less common sources...

  20. Pulsed Plasma Electron Sources

    Science.gov (United States)

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).