Gamma-ray bursts spectral correlations and their cosmological use

2007 ◽  
Vol 365 (1854) ◽  
pp. 1385-1394 ◽  
Author(s):  
Giancarlo Ghirlanda
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Selection Effects ◽  
Emission Energy ◽  
X Ray ◽  
New Class ◽  
The Universe ◽  
Prompt Emission ◽  
Open Issues

The correlations involving the long-gamma-ray bursts (GRBs) prompt emission energy represent a new key to understand the GRB physics. These correlations have been proved to be the tool that makes long-GRBs a new class of standard candles. Gamma Ray Bursts, being very powerful cosmological sources detected in the hard X-ray band, represent a new tool to investigate the Universe in a redshift range, which is complementary to that covered by other cosmological probes (SNIa and CMB). A review of the , , and correlations is presented. Open issues related to these correlations (e.g. presence of outliers and selection effects) and to their use for cosmographic purposes (e.g. dependence on model assumptions) are discussed. Finally, the relevance of thermal components in GRB spectra is discussed in the light of some of the models recently proposed for the interpretation of the spectral-energy correlations.

scholarly journals Statistical Analyses of the Energies of X-Ray Plateaus and Flares in Gamma-Ray Bursts

2022 ◽  
Vol 924 (2) ◽  
pp. 69
Author(s):  
Shuang-Xi Yi ◽  
Mei Du ◽  
Tong Liu
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Physical Origin ◽  
Radiation Mechanisms ◽  
Gaussian Distributions ◽  
Emission Energy ◽  
X Ray ◽  
Central Engine ◽  
Positive Correlations ◽  
Prompt Emission

Abstract Distinct X-ray plateau and flare phases have been observed in the afterglows of gamma-ray bursts (GRBs), and most of them should be related to central engine activities. In this paper, we collect 174 GRBs with X-ray plateau phases and 106 GRBs with X-ray flares. There are 51 GRBs that overlap in the two selected samples. We analyze the distributions of the proportions of the plateau energy E plateau and the flare energy E flare relative to the isotropic prompt emission energy E γ,iso. The results indicate that they well meet the Gaussian distributions and the medians of the logarithmic ratios are ∼−0.96 and −1.39 in the two cases. Moreover, strong positive correlations between E plateau (or E flare ) and E γ,iso with slopes of ∼0.95 (or ∼0.80) are presented. For the overlapping sample, the slope is ∼0.80. We argue that most of X-ray plateaus and flares might have the same physical origin but appear with different features because of the different circumstances and radiation mechanisms. We also test the applicabilities of two models, i.e., black holes surrounded by fractured hyperaccretion disks and millisecond magnetars, on the origins of X-ray plateaus and flares.

scholarly journals Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Dipole Radiation ◽  
X Ray ◽  
Radiative Efficiency ◽  
Central Engine ◽  
Radiative Losses ◽  
Wave Emission ◽  
Prompt Emission

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.

Gamma-Ray Bursts as X-Ray Depth Gauges of the Universe

2003 ◽  
Vol 591 (2) ◽  
pp. L91-L94 ◽  
Author(s):  
P. Mszros ◽  
M. J. Rees
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
X Ray ◽  
The Universe

scholarly journals Studying stellar explosions with Athena

2015 ◽  
Vol 11 (A29B) ◽  
pp. 243-243
Author(s):  
P. O'Brien ◽  
P. Jonker
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Intermediate Mass ◽  
Tidal Disruption ◽  
X Ray ◽  
Cosmic Vision ◽  
Esa Cosmic Vision ◽  
Supernova Explosions

AbstractAthena is the second large mission selected in the ESA Cosmic Vision plan. With its large collecting area, high spectral-energy resolution (X-IFU instrument) and impressive grasp (WFI instrument), Athena will truly revolutionise X-ray astronomy. The most prodigious sources of high-energy photons are often transitory in nature. Athena will provide the sensitivity and spectral resolution coupled with rapid response to enable the study of the dynamic sky. Potential sources include: distant Gamma-Ray Bursts to probe the reionisation epoch and find missing baryons in the cosmic web; tidal disruption events to reveal dormant supermassive and intermediate-mass black holes; and supernova explosions to understand progenitors and their environments. We illustrate Athenas capabilities and show how it will be able to constrain the nature of explosive transients including gas metallicity and dynamics.

scholarly journals Gamma Ray Bursts Spectral–Energy correlations: recent results

2010 ◽  
Vol 6 (S275) ◽  
pp. 344-348
Author(s):  
Giancarlo Ghirlanda
Keyword(s):  
Gamma Ray ◽  
Direct Proof ◽  
Spectral Energy ◽  
Selection Effects ◽  
Radiation Mechanism ◽  
Isotropic Energy ◽  
Time Resolved ◽  
Open Issue ◽  
Short Grbs ◽  
Prompt Emission

AbstractThe correlations between the rest frame peak of the νFν spectrum of GRBs (Epeak) and their isotropic energy (Eiso) or luminosity (Liso) could have several implications for the understanding of the GRB prompt emission. These correlations are presently founded on the time–averaged spectral properties of a sample of 95 bursts, with measured redshifts, collected by different instruments in the last 13 years (pre–Fermi). One still open issue is wether these correlations have a physical origin or are due to instrumental selection effects. By studying 10 long and 14 short GRBs detected by Fermi we find that a strong time–resolved correlation between Epeak and the luminosity Liso is present within individual GRBs and that it is consistent with the time–integrated correlation. This result is a direct proof of the existence in both short and long GRBs of a similar physical link between the hardness and the luminosity which is not due to instrumental selection effects. The origin of the Epeak – Liso correlation should be searched in the radiation mechanism of the prompt emission.

scholarly journals COSMOLOGY WITH THE Ep,i – Eiso CORRELATION OF GAMMA–RAY BURSTS

2012 ◽  
Vol 12 ◽  
pp. 19-27 ◽  
Author(s):  
LORENZO AMATI
Keyword(s):  
Photon Energy ◽  
Energy Band ◽  
Gamma Ray ◽  
Cosmological Parameters ◽  
Gamma Ray Bursts ◽  
Spectral Peak ◽  
X Ray ◽  
Radiated Energy ◽  
The Universe

Gamma–Ray Bursts (GRBs) are the brightest sources in the universe, emit mostly in the hard X–ray energy band and have been detected at redshifts up to about 8.2. Thus, they are in principle very powerful probes for cosmology. I shortly review the researches aimed to use GRBs for the measurement of cosmological parameters, which are mainly based on the correlation between spectral peak photon energy and total radiated energy or luminosity. In particular, based on an enriched sample of 120 GRBs, I will provide an update of the analysis by Amati et al. (2008) aimed at extracting information on ΩM and, to a less extent, on ΩΛ, from the E p,i – E iso correlation.

scholarly journals A complete sample of long bright Swift gamma ray bursts

2013 ◽  
Vol 371 (1992) ◽  
pp. 20120235 ◽  
Author(s):  
Gianpiero Tagliaferri ◽  
Ruben Salvaterra ◽  
Sergio Campana ◽  
Stefano Covino ◽  
Paolo D’Avanzo ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Cosmic Time ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Complete Sample ◽  
Peak Flux ◽  
S Peak ◽  
Prompt Emission

Complete samples are the basis of any population study. To this end, we selected a complete subsample of Swift long bright gamma ray bursts (GRBs). The sample, made up of 58 bursts, was selected by considering bursts with favourable observing conditions for ground-based follow-up observations and with the 15–150 keV 1 s peak flux above a flux threshold of 2.6 photons cm −2  s −1 . This sample has a redshift completeness level higher than 90 per cent. Using this complete sample, we investigate the properties of long GRBs and their evolution with cosmic time, focusing in particular on the GRB luminosity function, the prompt emission spectral-energy correlations and the nature of dark bursts.

STOCHASTIC WAKEFIELD PLASMA ACCELERATION IN GAMMA-RAY BURSTS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 627-632
Author(s):  
G. BARBIELLINI ◽  
F. LONGO ◽  
N. OMODEI ◽  
D. GIULIETTI ◽  
A. CELOTTI ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Plasma Acceleration ◽  
Gamma Ray Burst ◽  
Initial Burst ◽  
X Ray ◽  
Wake Field ◽  
Prompt Emission

Gamma-Ray Burst (GRB) prompt emission can, for specific conditions, be so powerful and short-pulsed to strongly influence any surrounding plasma. In this paper, we briefly discuss the possibility that a very intense initial burst of radiation produced by GRBs satisfy the intensity and temporal conditions to cause stochastic wake-field particle acceleration in a surrounding plasma of moderate density. We consider a simple but realistic GRB model for which particle wake-field acceleration can first be excited by a very strong low-energy precursor, and then be effective in producing the observed prompt X-ray and gamma-ray GRB emission.

A Comprehensive Study of Multiflare GRB Spectral Lag

2021 ◽  
Vol 922 (1) ◽  
pp. 34
Author(s):  
X. Z. Chang ◽  
Z. Y. Peng ◽  
J. M. Chen ◽  
Y. Yin ◽  
D. Z. Wang ◽  
...  
Keyword(s):  
Correlation Function ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Physical Origin ◽  
X Ray ◽  
Physical Mechanisms ◽  
Spectral Lag ◽  
Prompt Emission ◽  
Comprehensive Study

Abstract We select 48 multiflare gamma-ray bursts (GRBs) (including 137 flares) from the Swift/XRT database and estimate the spectral lag with the discrete correlation function. It is found that 89.8% of the flares have positive lags and only 9.5% of the flares show negative lags when fluctuations are taken into account. The median lag of the multiflares (2.75 s) is much greater than that of GRB pulses (0.18 s), which can be explained by the fact that we confirm that multiflare GRBs and multipulse GRBs have similar positive lag–duration correlations. We investigate the origin of the lags by checking the E peak evolution with the two brightest bursts and find the leading models cannot explain all of the multiflare lags and there may be other physical mechanisms. All of the results above reveal that X-ray flares have the same properties as GRB pulses, which further supports the observation that X-ray flares and GRB prompt-emission pulses have the same physical origin.

The late X-ray afterglow of gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1189-1195 ◽  
Author(s):  
Richard Willingale ◽  
Paul T O'Brien
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Indices ◽  
Plateau Phase ◽  
Start Time ◽  
X Ray ◽  
Temporal Decay ◽  
Decay Parameters ◽  
Steep Decay ◽  
Prompt Emission

We have developed a functional fit which can be used to represent the entire temporal decay of the X-ray afterglow of gamma-ray bursts (GRBs). The fit delineates and parameterizes well-defined phases for the decay: the prompt emission; an initial steep decay; a shallow plateau phase; and finally, a powerlaw afterglow. For 20% of GRBs, the plateau phase is weak, or not seen, and the initial powerlaw decay becomes the final afterglow. We compare the temporal decay parameters and X-ray spectral indices for 107 GRBs discovered by Swift with the expectations of the standard fireball model including a search for possible jet breaks. For approximately 50% of GRBs, the observed afterglow is in accord with the model, but for the rest the temporal and spectral properties are not as expected. We identify a few possible jet breaks, but there are many examples where such breaks are predicted but are absent. We also find that the start time of the final afterglow decay, T a , is associated with the peak of the prompt γ -ray emission spectrum, E peak , just as optical jet-break times, t j , are associated with E peak in the Ghirlanda relation.

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