scholarly journals The Correlation between Isotropic Energy and Duration of Gamma-Ray Bursts

2018 ◽  
Vol 869 (2) ◽  
pp. L23 ◽  
Author(s):  
Z. L. Tu ◽  
F. Y. Wang
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Isotropic Energy

scholarly journals The Maximum Isotropic Energy of Gamma-Ray Bursts

2017 ◽  
Vol 837 (2) ◽  
pp. 119 ◽  
Author(s):  
J.-L. Atteia ◽  
V. Heussaff ◽  
J.-P. Dezalay ◽  
A. Klotz ◽  
D. Turpin ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Isotropic Energy

The isotropic energy function and formation rate of short gamma-ray bursts

2021 ◽  
Vol 21 (10) ◽  
pp. 254
Author(s):  
Zhi-Ying Liu ◽  
Fu-Wen Zhang ◽  
Si-Yuan Zhu
Keyword(s):  
Energy Function ◽  
Gamma Ray ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Local Formation ◽  
Isotropic Energy ◽  
Energy Functions ◽  
Cosmic Evolution ◽  
First Time ◽  
The Universe

Abstract Gamma-ray bursts (GRBs) are brief, intense, gamma-ray flashes in the universe, lasting from a few milliseconds to a few thousand seconds. For short gamma-ray bursts (sGRBs) with duration less than 2 seconds, the isotropic energy (E iso) function may be more scientifically meaningful and accurately measured than the luminosity (L p) function. In this work we construct, for the first time, the isotropic energy function of sGRBs and estimate their formation rate. First, we derive the L p – E p correlation using 22 sGRBs with known redshifts and well-measured spectra and estimate the pseduo redshifts of 334 Fermi sGRBs. Then, we adopt the Lynden-Bell c − method to study isotropic energy functions and formation rate of sGRBs without any assumption. A strong evolution of isotropic energy E iso ∝ (1+z)5.79 is found, which is comparable to that between L p and z. After removing effect of the cosmic evolution, the isotropic energy function can be reasonably fitted by a broken power law, which is ϕ ( E iso , 0 ) ∝ E iso , 0 − 0.45 for dim sGRBs and ϕ ( E iso , 0 ) ∝ E iso , 0 − 1.11 for bright sGRBs, with the break energy 4.92 × 1049 erg. We obtain the local formation rate of sGRBs is about 17.43 events Gpc−3 yr−1. If assuming a beaming angle is 6° to 26°, the local formation rate including off-axis sGRBs is estimated as ρ 0,all = 155.79 – 3202.35 events Gpc−3 yr−1.

scholarly journals HIGH ENERGETIC GAMMA RAY BURSTS AND THEIR SPECTRAL PROPERTIES WITHIN THE FIRESHELL MODEL

2012 ◽  
Vol 12 ◽  
pp. 385-389
Author(s):  
B. PATRICELLI ◽  
M.G. BERNARDINI ◽  
C.L. BIANCO ◽  
L. CAITO ◽  
G. DE BARROS ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Observational Data ◽  
Spectral Properties ◽  
Gamma Ray ◽  
Emission Spectra ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Isotropic Energy ◽  
Thermal Spectrum ◽  
Prompt Emission

The analysis of various Gamma Ray Bursts (GRBs) characterized by an isotropic energy Eiso ≲ 1053 ergs within the fireshell model has shown how that the observed N(E) spectrum of their prompt emission can be reproduced in a satisfactory way by assuming a thermal spectrum in the comoving frame of the fireshell. Nevertheless, from the study of higher energetic bursts (Eiso ≳ 1054 ergs ) such as, for example, GRB 080319B, some discrepancies between the numerical simulations and the observational data have been observed. We investigate a different spectrum of photons in the comoving frame of the fireshell in order to better reproduce the spectral properties of GRB prompt emission within the fireshell model. We introduce a phenomenologically modified comoving thermal spectrum: a spectrum characterized by a different asymptotic low energy slope with respect to the thermal one. We test this spectrum by comparing the numerical simulations with the observed prompt emission spectra of various GRBs; we present, as an exaple, the case of GRB 080319B.

Erratum: “The Maximum Isotropic Energy of Gamma-Ray Bursts” (2017, ApJ, 837, 119)

2018 ◽  
Vol 852 (2) ◽  
pp. 144
Author(s):  
J.-L. Atteia ◽  
V. Heussaff ◽  
J.-P. Dezalay ◽  
A. Klotz ◽  
D. Turpin ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Isotropic Energy

scholarly journals Cosmology with Gamma-Ray Bursts Using k-correction

10.14311/1324 ◽  
2011 ◽  
Vol 51 (1) ◽  
Author(s):  
A. Kovács ◽  
Z. Bagoly ◽  
L. G. Balázs ◽  
I. Horváth ◽  
P. Veres
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Hubble Diagram ◽  
Isotropic Energy ◽  
The Universe ◽  
Comoving System

In the case of Gamma Ray Bursts with measured redshift, we can calculate the k-correction to get the fluence and energy that were actually produced in the comoving system of the GRB. To achieve this we have to use well-fitted parameters of GRB spectrum, available in the GCN database. The output of the calculations is the comoving isotropic energy Eiso, but this is not the endpoint: this data can be useful forestimating the ΩM parameter of the Universe and for making a GRB Hubble diagram usig Amati’s relation.

scholarly journals Bulk Lorentz factors of gamma-ray bursts

2018 ◽  
Vol 609 ◽  
pp. A112 ◽  
Author(s):  
G. Ghirlanda ◽  
F. Nappo ◽  
G. Ghisellini ◽  
A. Melandri ◽  
G. Marcarini ◽  
...  
Keyword(s):  
Density Profile ◽  
Rest Frame ◽  
Gamma Ray ◽  
Lorentz Factor ◽  
Gamma Ray Bursts ◽  
Opening Angle ◽  
Isotropic Energy ◽  
Upper Limits ◽  
Peak Energy ◽  
Short Event

Knowledge of the bulk Lorentz factor Γ0 of gamma-ray bursts (GRBs) allows us to compute their comoving frame properties shedding light on their physics. Upon collisions with the circumburst matter, the fireball of a GRB starts to decelerate, producing a peak or a break (depending on the circumburst density profile) in the light curve of the afterglow. Considering all bursts with known redshift and with an early coverage of their emission, we find 67 GRBs (including one short event) with a peak in their optical or GeV light curves at a time tp. For another 106 GRBs we set an upper limit tpUL. The measure of tp provides the bulk Lorentz factor Γ0 of the fireball before deceleration. We show that tp is due to the dynamics of the fireball deceleration and not to the passage of a characteristic frequency of the synchrotron spectrum across the optical band. Considering the tp of 66 long GRBs and the 85 most constraining upper limits, we estimate Γ0 or a lower limit Γ0LL. Using censored data analysis methods, we reconstruct the most likely distribution of tp. All tp are larger than the time Tp,γ when the prompt γ-ray emission peaks, and are much larger than the time Tph when the fireball becomes transparent, that is, tp>Tp,γ>Tph. The reconstructed distribution of Γ0 has median value ~300 (150) for a uniform (wind) circumburst density profile. In the comoving frame, long GRBs have typical isotropic energy, luminosity, and peak energy ⟨ Eiso ⟩ = 3(8) × 1050 erg, ⟨ Liso ⟩ = 3(15) × 1047 erg s-1, and ⟨ Epeak ⟩ = 1(2) keV in the homogeneous (wind) case. We confirm that the significant correlations between Γ0 and the rest frame isotropic energy (Eiso), luminosity (Liso), and peak energy (Ep) are not due to selection effects. When combined, they lead to the observed Ep−Eiso and Ep−Liso correlations. Finally, assuming a typical opening angle of 5 degrees, we derive the distribution of the jet baryon loading which is centered around a few 10-6M⊙.

scholarly journals Accounting for Selection Bias and Redshift Evolution in GRB Radio Afterglow Data

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 95
Author(s):  
Maria Dainotti ◽  
Delina Levine ◽  
Nissim Fraija ◽  
Poonam Chandra
Keyword(s):  
Rest Frame ◽  
Gamma Ray ◽  
High Redshift ◽  
Theoretical Models ◽  
Gamma Ray Bursts ◽  
Selection Effects ◽  
Isotropic Energy ◽  
X Ray ◽  
Optical Wavelengths ◽  
Observational Bias

Gamma-ray Bursts (GRBs) are highly energetic events that can be observed at extremely high redshift. However, inherent bias in GRB data due to selection effects and redshift evolution can significantly skew any subsequent analysis. We correct for important variables related to the GRB emission, such as the burst duration, T90*, the prompt isotropic energy, Eiso, the rest-frame end time of the plateau emission, Ta,radio*, and its correspondent luminosity La,radio, for radio afterglow. In particular, we use the Efron–Petrosian method presented in 1992 for the correction of our variables of interest. Specifically, we correct Eiso and T90* for 80 GRBs, and La,radio and Ta,radio* for a subsample of 18 GRBs that present a plateau-like flattening in their light curve. Upon application of this method, we find strong evolution with redshift in most variables, particularly in La,radio, with values similar to those found in past and current literature in radio, X-ray and optical wavelengths, indicating that these variables are susceptible to observational bias. This analysis emphasizes the necessity of correcting observational data for evolutionary effects to obtain the intrinsic behavior of correlations to use them as discriminators among the most plausible theoretical models and as reliable cosmological tools.

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