共查询到20条相似文献,搜索用时 46 毫秒
1.
Abbasi R Abdou Y Abu-Zayyad T Adams J Aguilar JA Ahlers M Andeen K Auffenberg J Bai X Baker M Barwick SW Bay R Bazo Alba JL Beattie K Beatty JJ Bechet S Becker JK Becker KH Benabderrahmane ML BenZvi S Berdermann J Berghaus P Berley D Bernardini E Bertrand D Besson DZ Bindig D Bissok M Blaufuss E Blumenthal J Boersma DJ Bohm C Bose D Böser S Botner O Braun J Brown AM Buitink S Carson M Chirkin D Christy B Clem J Clevermann F Cohen S Colnard C Cowen DF D'Agostino MV Danninger M Daughhetee J 《Physical review letters》2011,106(14):141101
IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18) eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence. 相似文献
2.
The high energy neutrino signature from proton-proton and photo-meson interactions in a supernova remnant shell ejected prior to a gamma-ray burst provides a test for the precursor supernova, or supranova, model of gamma-ray bursts. Protons in the supernova remnant shell and photons entrapped from a supernova explosion or a pulsar wind from a fast-rotating neutron star remnant provide ample targets for protons escaping the internal shocks of the gamma-ray burst to interact and produce high energy neutrinos. We calculate the expected neutrino fluxes, which can be detected by current and future experiments. 相似文献
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A. S. Lidvansky 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(11):1347-1349
Recent experiments with the Fermi-LAT and AGILE satellite gamma-ray telescopes, in which bursts of gamma-rays from the Crab Nebula were detected in the energy range of ~100 MeV, have aroused keen interest, if not a sensation. However, data on a possible burst in the Crab Nebula at much higher energies of ~100 TeV were published more than 20 years ago. Characteristics of transient and stationary fluxes of gamma rays from the Crab Nebula in various energy ranges are discussed in this work, and it is shown that the old data obtained at ultra-high energies is reasonably consistent with the latest pattern of the source’s burst activity. 相似文献
5.
M. Pamini L. Natalucci D. Dal Fiume F. Frontera E. Costa M. Salvati 《Il Nuovo Cimento C》1990,13(2):337-344
Summary The anticoincidence lateral shields of the high-energy ((15÷200) keV) detector PDS aboard the SAX satellite will be used to
detect celestial gamma-ray bursts. As a gamma-ray burst monitor (GRBM), the shields have a 5σ sensitivity in the (60÷600)
keV nominal energy band about 10−6 erg/cm2, and a capability of determining the burst location to an accuracy of a few tenths of degree to several degrees, depending
on burst direction and strength. The GRBM will be mainly devoted to study the burst time profile with a time resolution down
to 0.5 ms. Its expected performances are evaluated by means of Monte Carlo simulations.
To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee. 相似文献
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We investigate the gravitational collapse of a spherically symmetric, inhomogeneous star, which is described by a perfect fluid with heat flow and satisfies the equation of state p=ρ/3 at its center. In the process of the gravitational collapse, the energy
of the whole star is emitted into space. And the remaining spacetime
is a Minkowski one without a remnant at the end of the process. For a star with a solar mass and solar radius, the total energy emitted is at the
order of 1054 erg, and the time-scale of the process is
about 8 s. These are in the typical values for a gamma-ray burst.
Thus, we suggest the gravitational collapse of a spherical star with
heat flow as a possible energy mechanism of gamma-ray bursts. 相似文献
8.
V. B. Petkov E. V. Bugaev P. A. Klimai M. V. Andreev V. I. Volchenko G. V. Volchenko I. M. Dzaparova D. D. Dzhappuev A. N. Gaponenko Zh. Sh. Guliev N. F. Klimenko A. U. Kudzhaev A. V. Sergeev N. S. Khaerdinov A. B. Chernyaev A. F. Yanin 《Journal of Experimental and Theoretical Physics》2010,110(3):406-416
The energy spectra and temporal characteristics of high-energy gamma-ray bursts from evaporating primordial black holes have been calculated using various evaporation models. The currently existing theoretical uncertainties in the shape of the evaporated photon spectrum are discussed. The data from the Andyrchy and Carpet-2 arrays of the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) obtained in the mode of detection of a single cosmic-ray component are used to search for cosmic gamma-ray bursts with a primary photon energy of about 8 GeV. New upper limits have been obtained for the number density of evaporating black holes in a local region of space with a characteristic size of ~10?3 pc for various evaporation models. 相似文献
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Optical burst switching (OBS) has been proposed as a competitive hybrid switching technology to support the next generation optical Internet. However, due to their one-way resource reservation mechanism, OBS networks experience high bursts (thus packets) loss rate. In OBS networks, the contention is resolved either by dropping one of the contending bursts or more efficiently by dropping from one of the contending bursts only the parts that overlap with the other bursts. In both situations, only one data source will suffer the data loss in favor to the other. In this paper, a new burst flexible and enhancing bandwidth utilization burst dropping technique has been proposed for contention resolution in optical burst switched networks. When contention occurs, any part of a contending burst could be dropped, instead of only the head or tail of bursts. The proposed dropping scheme makes bandwidth utilization more efficient and flexible. Simulation results show that the proposed dropping scheme performs better than existing burst dropping schemes. 相似文献
11.
Ding Linkai Mu Jun Wang Hui Feng Zhenyong Ren Jingru Yu Guangce Zhou Wende Meng Xianru Meng Lie Zhang Chunsheng 《中国物理C(英文版)》1997,21(8):673-679
A search for gamma-ray bursts at 1OTeV energy region was made using data of Yangbajing air shower experiment in Tibet.About 4×108 events were analysed to search for shower clusters appearing in a given time interval and a given small sky bin. An equal-zenith angle method is adopted to estimate the background. Some clusters show excesses over the background but with less significance as the evidence of gamma-ray bursts.The much higher sensitivity of the Yangbajing second phase array to the detection of 1OTeV gamma-ray bursts is discussed. 相似文献
12.
Optical burst switching (OBS) has been proposed as a competitive switching technology to support the next generation optical Internet. However, due to their one-way resource reservation mechanism, OBS networks experience high bursts (thus packets) loss rate. In OBS networks, the contention is resolved either by dropping one of the contending bursts or more efficiently by dropping from one of the contending bursts only the parts that overlap with the other bursts. In both situations, only one data source will suffer the data loss in favor to the other. In this paper, a novel burst dropping policy based on even selection of burst (BDPES) has been proposed in conjunction with an appropriate mechanism to provide differentiated service in order to support the quality of service (QoS) requirements of different applications. In the proposed burst dropping policy, the dropped segments are selected evenly from both contending bursts and the truncated bursts are guaranteed to be larger than the minimum burst-length allowed by the network. Furthermore, the proposed policy is enhanced via a flow control mechanism. Simulation results show that the performance of proposed policy is better than existing burst dropping mechanisms in terms of reducing burst (packets) loss rate. 相似文献
13.
Relativistic beaming effect is an important radiation mechanism in explaining gamma-ray bursts, according to recent observed data by Compton Gamma-ray Observatory (CGRO). Pair production optical depth and relationship between Lorentz factor and spectral index have been calculated in considering non-uniform distribution of beam photons in gamma-ray bursts in this paper. As a comparison, we also calculate the minimum Lorenta factor for 54 observed gamma-ray bursts by CGRO. 相似文献
14.
Xiang-Yu Wang Xiao-Jun Bi Zhen Cao Piero Vallania Han-Rong Wu Da-Hai Yan Qiang Yuan 《中国物理C(英文版)》2022,(3):63-84
Extra-galactic gamma-ray sources,such as gamma-ray bursts,active galactic nuclei,starburst galaxies,are interesting and important targets for LHAASO observation... 相似文献
15.
A. A. Belyanin V. V. Kocharovsky VI. V. Kocharovsky 《Radiophysics and Quantum Electronics》1998,41(1):22-27
It is believed that the detection of gamma-ray bursts from evaporating primordial black holes is highly improbable in the near future since the expected photon flux, consisting mainly of photons with energies ? GeV, is too low. Contrary to this point of view, we show that a large fraction of the black hole power at the final stage of evaporation (the last 103 s) can be liberated as a burst of soft γ-ray emission of duration 10?1–103 s and luminosity 1028–1031 erg/s in the energy range 0.1–1 MeV. According to our calculations of the black hole evaporation rate (within the Standard Model of elementary particles), when the black hole temperature exceeds approximately 10 GeV, the charged particle outflow from a black hole forms a well-defined plasma and can be described in the hydrodynamic approximation. In this case more than half of the rest energy of a black hole can be converted into soft gamma-rays due to the presence of the magnetic field with energy density comparable to that of charged particles. We consider various mechanisms leading to such transformation and estimate their efficiency. It is shown that, at least, some of the gamma-ray bursts detected by BATSE can be associated with evaporating black holes. 相似文献
16.
Hypermassive neutron stars (HMNSs)--equilibrium configurations supported against collapse by rapid differential rotation--are possible transient remnants of binary neutron-star mergers. Using newly developed codes for magnetohydrodynamic simulations in dynamical spacetimes, we are able to track the evolution of a magnetized HMNS in full general relativity for the first time. We find that secular angular momentum transport due to magnetic braking and the magnetorotational instability results in the collapse of an HMNS to a rotating black hole, accompanied by a gravitational wave burst. The nascent black hole is surrounded by a hot, massive torus undergoing quasistationary accretion and a collimated magnetic field. This scenario suggests that HMNS collapse is a possible candidate for the central engine of short gamma-ray bursts. 相似文献
17.
Observations of ground-based telescopes and the Hubble space telescope made it possible to identify a part of gamma-ray bursts with far objects (redshift parameter Z ≥ 1).However, it remains unclear what are other bursts and what are their sources. The possibility of identifying other bursts with close sources known as small-mass flare stars is considered. The coordinates of space gamma-ray bursts (GRBs) for 2008–2013 and close stars (within the radius r < 25 pc) were compared by the correlation analysis method. Six coincidences were found with an accuracy of ~0.1°. The probability of accidental coincidence of GRBs with stars is 4 · 10?8, which undoubtedly proves their stellar origin. 相似文献
18.
With the prompt slewing capability of the X-ray and UV-optical telescopes onboard the Swift mission and with the gamma-ray large area telescope onboard the Fermi mission, gamma-ray bursts (GRBs) are now accessible in a full time window and in all electromagnetic wavelengths for the events. Many observational breakthroughs have been made in recent years. I present here a brief review of some observational breakthroughs with the two missions, focusing on how these breakthroughs have revolutionized our understanding of the nature of this phenomenon and puzzles as well as challenges of confronting the conventional models with data. 相似文献
19.
Mohlin P 《The Journal of the Acoustical Society of America》2011,129(6):3827-3836
This paper reports on listening tests performed to investigate the just audible tonality (JAT) of decaying pure tone bursts. Both exponential and Gaussian functions are used to shape the envelopes of the tone bursts and critical band center frequencies between 150 and 7000 Hz are studied. Loudness compensation is implemented to compensate for the reduced loudness of short tone bursts and attack functions are used for minimizing clicks. By using the method of limits, a sequence of tone bursts with increasing decay times and constant frequencies is presented to the listeners at 0.9 s intervals. The first burst in the sequence which is perceived as being tonal is indicated by the listeners. When that happens, the decay times of the tone bursts decrease and the listeners are asked to select the first tone burst with no audible tonality. The listeners are allowed to freely define tonality. No reference is given. For frequencies above 3.4 kHz, the results indicate that tonality is just audible for tone burst lengths of approximately 2.6-3.0 ms. For the lowest stimuli frequencies, the corresponding burst length is approximately 20-23 ms. 相似文献
20.
I. V. Arkhangelskaja 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(4):419-423
The duration of gamma ray bursts (GRBs) is usually characterized by time interval t 90, in which the total number of registered counts grows from 5 to 95%. Classes of short and long GRBs were first detected in analyzing the BATSE experiment data from the Compton Gamma Ray Observatory (CGRO); burst duration separation point was found to be t 90lim ~2 s. A group of bursts of intermediate duration was first detected in analyzing the data of the same experiment in 1999 in the interval of ~1 to ~40 s with an average event duration of 〈t 90〉 ~ 3.5 s. The results from analyzing the catalog of gamma-ray burst data selected while ground processing BATSE data (i.e., the catalog of nontriggered events) showed that the intensity of intermediate bursts is lower than that of short and long bursts. Preliminary results from investigating the GBM catalog (onboard the Fermi Space Observatory) and the BAT catalog (onboard the Swift satellite) confirm the detection of events with similar properties. 相似文献