scholarly journals Broad band X-ray spectral properties of gamma-ray bursts with BeppoSAX

Author(s):  
F. Frontera ◽  
L. Amati ◽  
E. Costa ◽  
M. Feroci ◽  
J. M. Muller ◽  
...  
1987 ◽  
Vol 125 ◽  
pp. 477-487
Author(s):  
W. Doyle Evans ◽  
John G. Laros

Gamma-ray bursts are generally believed to originate in the vicinity of neutron stars, but the phenomenology is still not understood. In this paper we review the known characteristics of gamma bursts and give new observational results on temporal and spectral properties. We suggest that a class of repeating bursters exists that are spectrally harder than x-ray bursters but significantly softer than “classical” gamma bursts. The March 5, 1979, burst may be the prototype of this class of bursters.


2007 ◽  
Vol 671 (2) ◽  
pp. 1921-1938 ◽  
Author(s):  
A. D. Falcone ◽  
D. Morris ◽  
J. Racusin ◽  
G. Chincarini ◽  
A. Moretti ◽  
...  

2019 ◽  
Vol 486 (2) ◽  
pp. 1741-1762 ◽  
Author(s):  
L Foffano ◽  
E Prandini ◽  
A Franceschini ◽  
S Paiano

ABSTRACT Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of blazars with exceptional spectral properties. The non-thermal emission of the relativistic jet peaks in the spectral energy distribution (SED) plot with the synchrotron emission in X-rays and with the gamma-ray emission in the TeV range or above. These high photon energies may represent a challenge for the standard modelling of these sources. They are important for the implications on the indirect measurements of the extragalactic background light, the intergalactic magnetic field estimate, and the possible origin of extragalactic high-energy neutrinos. In this paper, we perform a comparative study of the multiwavelength spectra of 32 EHBL objects detected by the Swift-BAT telescope in the hard X-ray band and by the Fermi-LAT telescope in the high-energy gamma-ray band. The source sample presents uniform spectral properties in the broad-band SEDs, except for the TeV gamma-ray band where an interesting bimodality seems to emerge. This suggests that the EHBL class is not homogeneous, and a possible subclassification of the EHBLs may be unveiled. Furthermore, in order to increase the number of EHBLs and settle their statistics, we discuss the potential detectability of the 14 currently TeV gamma-ray undetected sources in our sample by the Cherenkov telescopes.


2018 ◽  
Vol 615 ◽  
pp. A80
Author(s):  
A. Pescalli ◽  
M. Ronchi ◽  
G. Ghirlanda ◽  
G. Ghisellini

The prompt emission of gamma-ray bursts extends from the early pulses observed in γ-rays (>15 keV) to very late flares of X-ray photons (0.3–10 keV). The duration of prompt γ-ray pulses is rather constant, while the width of X-ray flares correlates with their peak time, suggesting a possibly different origin. However, pulses and flares have similar spectral properties. Considering internal and external shock scenarios, we derive how the energy and duration of pulses scale with their time of occurrence, and we compare this with observations. The absence of an observed correlation between the prompt emission pulse duration and its time of occurrence favours an “internal” origin and confirms earlier results. We show that the energetic and temporal properties of X-ray flares are also consistent with being produced by internal shocks between slow fireballs with a small contrast between their bulk Lorentz factors. These results relax the requirement of a long-lasting central engine to explain the latest X-ray flares.


2006 ◽  
Vol 367 (4) ◽  
pp. 1473-1477 ◽  
Author(s):  
Y. Tikhomirova ◽  
B. E. Stern ◽  
A. Kozyreva ◽  
J. Poutanen

2021 ◽  
Vol 366 (4) ◽  
Author(s):  
Zhi-Ying Liu ◽  
Fu-Wen Zhang ◽  
Si-Yuan Zhu

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton

ABSTRACT The spin-down energy of millisecond magnetars has been invoked to explain X-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. Here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as $n=4.85^{+0.11}_{-0.15}$ suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission.


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