共查询到20条相似文献，搜索用时 125 毫秒
1.
C. Barat G. Chambon K. Hurley M. Niel G. Vedrenne I. V. Estulin A. V. Kuznetsov V. M. Zenchenko 《Astrophysics and Space Science》1981,75(1):83-91
The three-satellite SIGNE network has observed 26 confirmed gamma-ray bursts in the period September 1978–June 1979. Burst time histories may be used to define several classes of events, with a strong resemblance between events in a given class, but different arrival directions. The spectra of two gamma-ray bursts have been found to evolve from shapes which turn over at low energy during the start of the event, to near power law spectra at the end of the event.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts held at Toulouse, France, 26–29 November, 1979. 相似文献
2.
The observation of infrared bursts from the globular cluster Liller I has been reported by Kulkarniet al. (1979) and confirmed by Joneset al. (1980). The infrared bursts which resemble Type I X-ray bursts in their characteristics are plausibly attributed to a cyclotron maser instability operating at few tens of neutron star radii above the poles of a magnetized neutron star in a binary system. It is suggested that similar infrared bursts should in general be observable from Type I X-ray burst sources. 相似文献
3.
Observations of 85 gamma bursts by the KONUS instruments on the Venera 11 and Venera 12 spacecraft in the period September 1978 to May 1979 inclusive have provided proof of a galactic localization of the gamma-burst sources based on an analysis of the logN-logS plot and the revealed anisotropy in the angular distribution of sources over the celestial sphere. Evaluation of the energy released in the sources yields 1040–1041 erg. There apparently exist several types of gamma bursts differing in time profile, duration and shape of their energy spectrum. In some cases, extensive evolution of the energy spectrum is observed during a burst. The discovery of a flaring X-ray pulsar in Dorado has provided the first observational evidence for a connection of gamma bursts with neutron stars. Repeated short bursts from this source have revealed for the first time the recurrent features of this phenomenon. Repeated bursts have been detected from one more source in the short burst class. The data obtained thus far impose a number of restrictions on the applicability of many theoretical suggestions concerning the nature of the gamma bursts. The most plausible model for the gamma-burst source appears to be a binary with a neutron star with strongly non-stationary accretion involving, possibly, non-stationary thermonuclear fusion of matter falling onto the surface of a degenerate star.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts, held at Toulouse, France, 26–29 November, 1979. 相似文献
4.
W. D. Evans E. E. Fenimore R. W. Klebesadel J. G. Laros N. J. Terrell 《Astrophysics and Space Science》1981,75(1):35-46
The LASL Pioneer Venus Orbiter Gamma Burst Detector (OGBD) is a vital element in the long base-line array of similar instruments intended to precisely locate sources of gamma-ray bursts. Results of early observations are described. The source of the gamma-ray burst of 5 March, 1979 (the first to be located with precision) has been determined to be consistent with the direction of supernova remnant N49 within the LMC. Approximate locations defined for a small number of events suggest no departure from an isotropic distribution.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts held at Toulouse, France, 26–29 November 1979. 相似文献
5.
The peculiar -ray burst phenomenon of 5 March, 1979, and the other subsequent bursts on 6 March, 4 April, and 24 April, 1979, are studied, using the physically more realistic exponentially increasing accretion rate on a highly magnetized neutron star from its companion, and the conclusions that pycnonuclear reaction flash for the first and thermonuclear flashes for the subsequent bursts as the most probable model for this series of bursts, are made.We further conclude that a huge -ray burst is a sequel to rapid X-ray transient or type-I X-ray bursts, i.e., an almost exactly similar burst as on 5 April, 1979 will never repeat from the same source, instead rapid X-ray transient burst, or type-I X-ray burst will be occured. A rough estimate gives that the next burst will occur within 0.5 yr since 24 April, 1979. 相似文献
6.
F. Frontera F. Fuligni E. Morelli G. Pizzichini G. Ventura 《Astrophysics and Space Science》1981,75(1):211-217
It is known that the counting rate of both Nai and Csi hard X-ray detectors can have intense enhancements of brief (<1 s) duration, which appear like very short cosmic gamma-ray bursts but probably are due to phosphorescence in the detector itself. Unfortunately, this problem is not limited to short bursts. We present here three much longer (up to 80 s) pseudo-gamma-ray bursts observed during a transatlantic ballon flight. We conclude that detections of gamma-ray bursts (and probably also of hard X-ray source flares) based only on a rate increase by a single scintillator should always be confirmed by at least one other instrument.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts held at Toulouse, France, 26–29 November, 1979. 相似文献
7.
Measurements made during 1976–1979 at the Aarne Karjalainen Observatory show slight east-west asymmetry of Saturn's ring B. 相似文献
8.
Fifteen type II solar radio events have been identified in the 2 MHz to 30 kHz frequency range by the radio astronomy experiment on the ISEE-3 satellite over the period from September 1978 to December 1979. These data provide the most comprehensive sample of type II radio bursts hitherto observed at kilometer wavelengths. Dynamic spectra of a number of events are presented. Where possible, the 15 events have been associated with an initiating flare, ground-based radio data, the passage of a shock at the spacecraft and the sudden commencement of a geomagnetic storm. The general characteristics of kilometric type II bursts are discussed.Research Associate, University of Maryland, U.S.A. 相似文献
9.
Jorma J. Riihimaa 《Astrophysics and Space Science》1977,51(2):363-383
Dynamic spectra of Jupiter's S-bursts are observed with sweep-frequency and multi-channel receivers operating at frequency ranges 21–30 and 20.85–23.20 MHz, respectively. Spectra obtained with time resolutions of 0.2, 0.02, and 0.004 s are compared, the frequency resolution being 50 kHz. The most normal appearance of S-bursts is in trains with a frequency range of the order of 1 MHz. Narrow-band Strains also occur. Narrow-band L-emissions in region B are often associated with S-bursts, obviously in the manner described by Flagget al. (1976). Synoptic spectral observations indicate that region B for S-bursts exhibits a drift in longitude similar to that for L-bursts. The Io phase profile for S-bursts has a maximum in the vicinity of 80° in region B and 230° in region C. S-bursts observed in 1976 have higher drift rates than those compiled by Krauscheet al. (1976). Region C bursts have simpler spectra and lower drift rates than region B bursts. 相似文献
10.
J. -L. Puget 《Astrophysics and Space Science》1981,75(1):109-116
A review of recent theoretical work on gamma-ray bursts is given. The emphasis is put on the localization of sources. It is concluded that sources of gamma-ray bursts must be either old Population I or Population II objects with a mechanism implying that the sources are not too far from the galactic plane. According to this conclusion the more relevant models are probably flare stars or accretion on old neutron stars, radiation of the gravitational energy of the accretion, or thermonuclear explosions.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts, held at Toulouse, France, 26–29 November, 1979. 相似文献
11.
R. Guerriero D. W. Fox J. Kommers W. H. G. Lewin R. Rutledge C. B. Moore E. Morgan J. Van Paradijs M. Van der Klis L. Bildsten T. Dotani 《Monthly notices of the Royal Astronomical Society》1999,307(1):179-189
We describe the evolutionary progression of an outburst of the Rapid Burster. Four outbursts have been observed with the Rossi X-Ray Timing Explorer between 1996 February and 1998 May, and our observations are consistent with a standard evolution over the course of each. An outburst can be divided into two distinct phases. Phase I is dominated by type I bursts, with a strong persistent emission component; it lasts for 15–20 d. Phase II is characterized by type II bursts, which occur in a variety of patterns. The light curves of time-averaged luminosity for the outbursts show some evidence for reflares, similar to those seen in soft X-ray transients. The average recurrence time for Rapid Burster outbursts during this period was 218 d, in contrast to an average ∼180‐d recurrence period observed during 1976–1983. 相似文献
12.
Simultaneous observations of type III radio bursts from spacecraft separated by 0.43 AU have been made using the solar orbiters HELIOS-A and HELIOS-B. The burst beginning at 19:22 UT on March 28, 1976 has been located from the intersection of the source directions measured at each spacecraft, and from burst arrival time differences. The source positions range from 0.03 AU from the Sun at 3000 kHz to 0.08 AU at 585 kHz. The electron density along the burst trajectory, and the exciter velocity (=0.13c) were determined directly, without the need to assume a density model as has been done with single-spacecraft observations. The separation of HELIOS-A and -B has also provided the first measurements of burst directivity at low frequencies. For the March 28 burst the intensity observed from near the source longitude (HELIOS-B) was 3–10 dB greater than that from 60° west of the source (HELIOS-A). 相似文献
13.
E. P. Mazets S. V. Golenetskii Yu. A. Guryan V. N. Ilyinskii 《Astrophysics and Space Science》1982,84(1):173-189
A comparison of the 5 March 1979 event and other short gamma-ray bursts reveals considerable similarities in their features. This implies their common origin. 相似文献
14.
Gamma-ray burst observations performed by LASL began with the identification and initial report of the phenomenon from data acquired by the Vela satellites. The Vela instruments have recorded responses to 73 gamma-ray bursts over a ten-year interval, and are continuing to contribute toward these observations. Similar instrumentation was included aboard the NRL SOLRAD 11 spacecraft. These performed well but suffered an early demise. Recently, the LASL gamma-ray burst astronomy program has been enhanced through the implementation of experiments aboard the Pioneer Venus Orbiter and ISEE-C spacecraft. Both of these experiments are continuing to contribute data vital to trigonometric directional analyses.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts, held at Toulouse, France, 26–29 November, 1979. 相似文献
15.
V. A. Sergeev A. G. Yahnin R. A. Rakhmatulin S. I. Solovjev F. S. Mozer D. J. Williams C. T. Russell 《Planetary and Space Science》1986,34(12):1169-1188
Auroral, magnetic variation and pulsation data from the dense network in the nearmidnight portion of the auroral zone are used together with the measurements of suprathermal particles and electromagnetic fields by the IMP-8 and ISEE-1 spacecraft within the plasma sheet to study the characteristics of activity during two magnetically quiet periods on 3 March 1976 and 23 March 1979. Contrary to existing beliefs, we found clear signatures of numerous (5–10 events per hour) transient events, characterized by plasma flows, energetic particle bursts and E−B field variations. A close association of these events in the plasma sheet with the local auroral flares (LAFs) in the conjugate sector of the auroral zone is established for many events. We conclude that LAF (local auroral arc activation with associated Pi pulsations but extremely weak magnetic bays) have the same plasma sheet manifestations (apparently, the same physics) as the individual substorm intensifications during strong substorm expansion events, which differ from the studied quiet periods mainly by the strength and number of these intensifications. These transient phenomena seem to play an important role in the energetics of the quiet time magnetotail. 相似文献
16.
太阳射电爆发(Solar Radio Burst, SRB)是太阳高能电子与背景等离子体相互作用产生的感应辐射现象,其多样的动力学谱类型及其复杂的精细结构反映了辐射源区磁等离子体结构状态丰富的物理信息,而相关辐射机制则是解读相关物理信息的关键工具.长期以来,在SRB辐射机制的研究中一直存在着争议不决的两种主要机制,即等离子体辐射机制和电子回旋脉泽(Electron Cyclotron Maser, ECM)辐射机制.近年来,针对传统的ECM辐射机制应用到SRB现象时遇到的一些主要困难,发展了由幂律谱电子低能截止驱动和包含快电子束自生阿尔文波效应的新型ECM驱动模型,并成功应用于解释各类不同SRB动力学谱的形成机制.基于这些新型的ECM辐射模型,系统地总结了ECM辐射机制在各种不同类型SRB现象中的应用,并对它们不同动力学谱结构的形成给出了一致统一的物理解释. 相似文献
17.
Graziella Pizzichini 《Astrophysics and Space Science》1981,75(1):205-210
One of the most recent discoveries on gamma-ray bursts was the fact that one, or possibly two, of them had a pulsed emission with a periodicity of 8 and 4 s. The intensity of successive peaks decreased exponentially with time. We can speculate that the energy range and/or the lack of sensitivity are probably the reasons why periodicities were not discoverded in some other bursts. In fact, many time-histories show a double or multiple peak structure. If they were periodic, the distance between successive peaks would be equal to the period. Based on this extremely simplified assumption, a search on all available gamma-ray burst time-histories shows that most the periodicities above 1 s should be contained within an interval between 1 and 9 s, with a maximum at approximately 3 s.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts held at Toulouse, France, 26–29 November, 1979. 相似文献
18.
E. P. Mazets S. V. Golenetskii V. N. Ilyinskii V. N. Panov R. L. Aptekar Yu. A. Guryan M. P. Proskura I. A. Sokolov Z. Ya. Sokolova T. V. Kharitonova A. V. Dyatchkov N. G. Khavenson 《Astrophysics and Space Science》1981,80(1):3-83
Data are presented on the temporal structure, fluxes, energy spectra and coordinates of the sources of gamma-ray bursts detected in the KONUS experiment on Venera 11 and Venera 12 space probes in the period September 1978 to May 1979. The statistical distributions of gamma bursts in duration, intensity, and peak power, as well as the distribution of the burst sources over the celestial sphere presented are based on the updated KONUS information obtained until February 1980. 相似文献
19.
Takeo Kosugi 《Solar physics》1981,71(1):91-105
A well-developed multiple impulsive microwave burst occurred on February 17, 1979 simultaneously with a hard X-ray burst and a large group of type III bursts at metric wavelengths. The whole event is composed of several subgroups of elementary spike bursts. Detailed comparisons between these three classes of emissions with high time resolution of 0.5 s reveal that individual type III bursts coincide in time with corresponding elementary X-ray and microwave spike bursts. It suggests that a non-thermal electron pulse generating a type III spike burst is produced simultaneously with those responsible for the corresponding hard X-ray and microwave spike bursts. The rise and decay characteristic time scales of the elementary spike burst are 1 s, 1 s and 3 s for type III, hard X-ray and microwave emissions respectively. Radio interferometric observations made at 17 GHz reveal that the spatial structure varies from one subgroup to others while it remains unchanged in a subgroup. Spectral evolution of the microwave burst seems to be closely related to the spatial evolution. The spatial evolution together with the spectral evolution suggests that the electron-accelerating region shifts to a different location after it stays at one location for several tens of seconds, duration of a subgroup of elementary spike bursts. We discuss several requirements for a model of the impulsive burst which come out from these observational results, and propose a migrating double-source model. 相似文献
20.
Miloslav Zejda Zdeněk Mikulášek Marek Wolf Ondřej Pejcha 《Astrophysics and Space Science》2006,304(1-4):161-163
We have re-analyzed old photometric UBV data obtained by Papoušek et al. at Skalnaté Pleso, Slovakia (1967–1980) and Brno, Czech Republic (1976–1979) observatories and analyzed new own CCD measurements (Brno, 2003–2005). In both set of photometric data the oscillations in the vicinity of the primary minimum were found. The detected periods are compatible with the previously published ones. 相似文献