scholarly journals Time-resolved spectral correlations of long-duration γ-ray bursts

2009 ◽  
Vol 393 (4) ◽  
pp. 1209-1218 ◽  
Author(s):  
C. Firmani ◽  
J. I. Cabrera ◽  
V. Avila-Reese ◽  
G. Ghisellini ◽  
G. Ghirlanda ◽  
...  
Keyword(s):  
2019 ◽  
Vol 486 (2) ◽  
pp. 1781-1795 ◽  
Author(s):  
Bhoomika Rajput ◽  
C S Stalin ◽  
S Sahayanathan ◽  
Suvendu Rakshit ◽  
Amit Kumar Mandal

ABSTRACT Blazars show optical and γ-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical, ultraviolet, X-ray, and γ-ray energies, spanning about 9 yr from 2008 August to 2017 February. We have identified four time intervals (epochs), A, B, D, and E, when the source showed large-amplitude optical flares. In epochs A and B the optical and γ-ray flares are correlated, while in D and E corresponding flares in γ-rays are weak or absent. In epoch B the degree of optical polarization strongly correlates with changes in optical flux during a short-duration optical flare superimposed on one of long duration. In epoch E the optical flux and degree of polarization are anticorrelated during both the rising and declining phases of the optical flare. We carried out broad-band spectral energy distribution (SED) modelling of the source for the flaring epochs A,B, D, and E, and a quiescent epoch, C. Our SED modelling indicates that optical flares with absent or weak corresponding γ-ray flares in epochs D and E could arise from changes in a combination of parameters, such as the bulk Lorentz factor, magnetic field, and electron energy density, or be due to changes in the location of the γ-ray-emitting regions.


Nature ◽  
2006 ◽  
Vol 444 (7122) ◽  
pp. 1047-1049 ◽  
Author(s):  
Johan P. U. Fynbo ◽  
Darach Watson ◽  
Christina C. Thöne ◽  
Jesper Sollerman ◽  
Joshua S. Bloom ◽  
...  
Keyword(s):  

2003 ◽  
Vol 27 (2) ◽  
pp. 152-157
Author(s):  
Shen Rong-feng ◽  
Song Li-ming
Keyword(s):  

Science ◽  
2013 ◽  
Vol 343 (6166) ◽  
pp. 48-51 ◽  
Author(s):  
A. Maselli ◽  
A. Melandri ◽  
L. Nava ◽  
C. G. Mundell ◽  
N. Kawai ◽  
...  

Long-duration gamma-ray bursts (GRBs) are an extremely rare outcome of the collapse of massive stars and are typically found in the distant universe. Because of its intrinsic luminosity (L ∼ 3 × 1053 ergs per second) and its relative proximity (z = 0.34), GRB 130427A reached the highest fluence observed in the γ-ray band. Here, we present a comprehensive multiwavelength view of GRB 130427A with Swift, the 2-meter Liverpool and Faulkes telescopes, and by other ground-based facilities, highlighting the evolution of the burst emission from the prompt to the afterglow phase. The properties of GRB 130427A are similar to those of the most luminous, high-redshift GRBs, suggesting that a common central engine is responsible for producing GRBs in both the contemporary and the early universe and over the full range of GRB isotropic energies.


2010 ◽  
Vol 59 (12) ◽  
pp. 3262-3269 ◽  
Author(s):  
Zachary J. Taylor ◽  
Roi Gurka ◽  
Gregory A. Kopp ◽  
Alex Liberzon

2009 ◽  
Vol 700 (1) ◽  
pp. L47-L50 ◽  
Author(s):  
Davide Lazzati ◽  
Brian J. Morsony ◽  
Mitchell C. Begelman

2007 ◽  
Vol 668 (1) ◽  
pp. 384-391 ◽  
Author(s):  
Hsiao‐Wen Chen ◽  
Jason X. Prochaska ◽  
Joshua S. Bloom
Keyword(s):  

2020 ◽  
Vol 493 (4) ◽  
pp. 4845-4851 ◽  
Author(s):  
Zhongxiang Wang ◽  
Yi Xing ◽  
Jujia Zhang ◽  
Konstantina Boutsia ◽  
Gege Wang ◽  
...  

ABSTRACT 4FGL J0935.3+0901 is a γ-ray source detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope. We have conducted detailed analysis of the LAT data for this source and multiwavelength studies of the source field. Its γ-ray emission can be described with a power law (Γ = 2.0 ± 0.2) with an exponential cut-off (Ec = 2.9 ± 1.6 GeV), while the flux shows significant long-term variations. From analysis of archival Neil Gehrels Swift Observatory X-Ray Telescope data, we find only one X-ray source in the LAT’s 2σ error region. Within a $3.7\,{\rm arcsec}$ radius error circle of the X-ray source, there is only one optical object down to r′ ∼ 23 mag. Time-resolved photometry of the optical object indicates a likely 2.5 h periodic modulation, while its spectrum shows double-peaked hydrogen and helium emission lines (similar to those seen in accretion discs in low-mass X-ray binaries). Combining these results, we conclude that we have discovered a compact X-ray emitting binary in likely association with 4FGL J0935.3+0901, i.e. a millisecond pulsar (MSP) binary. We discuss the implication of the optical spectral features: this binary could be a transitional MSP system at a subluminous disc state, although the other possibility, the binary in a rotation-powered state showing the optical emission lines due to intrabinary interaction processes, cannot be excluded. Further observational studies will help to determine detailed properties of this candidate MSP binary and thus clarify its current state.


Nature ◽  
1994 ◽  
Vol 372 (6507) ◽  
pp. 652-654 ◽  
Author(s):  
K. Hurley ◽  
B. L. Dingus ◽  
R. Mukherjee ◽  
P. Sreekumar ◽  
C. Kouveliotou ◽  
...  

2018 ◽  
Vol 8 (10) ◽  
pp. 1706 ◽  
Author(s):  
Jianhao Wang ◽  
Songbai Xue ◽  
Zhaoping Lv ◽  
Li Wen ◽  
Siyi Liu

Cosmic radiation has always been the most obvious barrier to planetary travels, especially in long-duration deep space exploration missions. Therefore, the reliability of satellite materials and the requirements of satellite miniaturization have received considerable attention. In this paper, the effect of γ-ray irradiation on the reliability of Sn50Pb49Sb1/Cu solder joints was investigated. It was found that the influence of γ-ray irradiation on the thickness and morphology of the intermetallic compound layer in Sn50Pb49Sb1/Cu was not obvious. However, the formation and growth of micro-voids and micro-cracks was observed in Pb-based solid solutions. Due to the Compton effect, the γ-ray photon could knock the electron out of its orbit, which created the energetic electron. The accumulation of dislocated atoms and lattice vacancies generated by energetic electrons could be the main factor that caused the formation of micro-voids and micro-cracks. The pull force of Sn50Pb49Sb1/Cu solder joints was reduced by 22% after being irradiated at the dose rate of 0.25 Gy(Si)/s for 960 h. Fractographic analysis showed that after irradiation, the fracture type of solder joints was still ductile but the ductility of the solder joints decreased with slightly inconspicuous dimples.


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