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.

scholarly journals The properties of prompt emission in short gamma-ray bursts with extended emission observed by Fermi/GBM

2020 ◽  
Vol 492 (3) ◽  
pp. 3622-3630
Author(s):  
Lin Lan ◽  
Rui-Jingi Lu ◽  
Hou-Jun Lü ◽  
Jun Shen ◽  
Jared Rice ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Large Scatter ◽  
Intrinsic Properties ◽  
Temporal Properties ◽  
Peak Energy ◽  
Peak Flux ◽  
Short Grbs ◽  
Prompt Emission ◽  
Extended Emission

ABSTRACT Short gamma-ray bursts (GRB) with extended emission (EE) that are composed of an initial short hard spike followed by a long-lasting EE are thought to comprise a sucategory of short GRBs. The narrow energy band available during the Swift era, combined with a lack of spectral information, prevented the discovery of the intrinsic properties of these events. In this paper, we perform a systematic search of short GRBs with EE using all available Fermi/GBM data. The search identified 26 GBM-detected short GRBs with EE that are similar to GRB 060614 observed by Swift/BAT. We focus on investigating the spectral and temporal properties of both the hard spike and the EE component of all 26 GRBs, and explore differences and possible correlations between them. We find that while the peak energy (Ep) of the hard spikes is slightly harder than that of the EE, their fluences are comparable. The harder Ep seems to correspond to a larger fluence and peak flux, with a large scatter for both the hard spike and the EE component. Moreover, the Ep of both the hard spike and the EE are compared with other short GRBs. Finally, we also compare the properties of GRB 170817A with those of short GRBs with EE and find no significant statistical differences between them. We find that GRB 170817A has the lowest Ep, probably because it is off-axis.

scholarly journals RAPID OPTICAL FOLLOW-UP OBSERVATIONS OF GAMMA-RAY BURSTS

2012 ◽  
Vol 12 ◽  
pp. 48-57
Author(s):  
MICHEL BOËR
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
Gamma Ray Burst ◽  
Infrared Wavelengths ◽  
New Instruments ◽  
Prompt Emission

The prompt emission of gamma-ray burst sources is still the main means of detection, and a privilegied access to the souce dynamics. It is detected from radio to GeV energies, and its study is crucial for the overall understanding of the phenomenom. We present here a panorama of the rapid optical observations, and what can be infered from the data. We will discuss also the new instruments which are planned for the observation of the prompt and early afterglow at optical and infrared wavelengths, with spectral capabilities.

scholarly journals The luminosity function and formation rate of a complete sample of long gamma-ray bursts

2019 ◽  
Vol 488 (4) ◽  
pp. 4607-4613 ◽  
Author(s):  
Guang-Xuan Lan ◽  
Hou-Dun Zeng ◽  
Jun-Jie Wei ◽  
Xue-Feng Wu
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Likelihood Method ◽  
Complete Sample ◽  
Empirical Density ◽  
Power Law Function ◽  
Current Sample ◽  
First Time

ABSTRACT We study the luminosity function and formation rate of long gamma-ray bursts (GRBs) by using a maximum likelihood method. This is the first time this method is applied to a well-defined sample of GRBs that is complete in redshift. The sample is composed of 99 bursts detected by the Swift satellite, 81 of them with measured redshift and luminosity for a completeness level of $82\, {\rm per\, cent}$. We confirm that a strong redshift evolution in luminosity (with an evolution index of $\delta =2.22^{+0.32}_{-0.31}$) or in density ($\delta =1.92^{+0.20}_{-0.21}$) is needed in order to reproduce the observations well. But since the predicted redshift and luminosity distributions in the two scenarios are very similar, it is difficult to distinguish between these two kinds of evolutions only on the basis of the current sample. Furthermore, we also consider an empirical density case in which the GRB rate density is directly described as a broken power-law function and the luminosity function is taken to be non-evolving. In this case, we find that the GRB formation rate rises like $(1+z)^{3.85^{+0.48}_{-0.45}}$ for $z\lesssim 2$ and is proportional to $(1+z)^{-1.07^{+0.98}_{-1.12}}$ for $z\gtrsim 2$. The local GRB rate is $1.49^{+0.63}_{-0.64}$ Gpc−3 yr−1. The GRB rate may be consistent with the cosmic star formation rate (SFR) at $z\lesssim 2$, but shows an enhancement compared to the SFR at $z\gtrsim 2$.

scholarly journals A complete sample of brightSwiftlong gamma-ray bursts: testing the spectral-energy correlations

2012 ◽  
Vol 421 (2) ◽  
pp. 1256-1264 ◽  
Author(s):  
L. Nava ◽  
R. Salvaterra ◽  
G. Ghirlanda ◽  
G. Ghisellini ◽  
S. Campana ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Complete Sample

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 Prevalence of Extra Power-Law Spectral Components in Short Gamma-Ray Bursts

2021 ◽  
Vol 922 (2) ◽  
pp. 255
Author(s):  
Qing-Wen Tang ◽  
Kai Wang ◽  
Liang Li ◽  
Ruo-Yu Liu
Keyword(s):  
Power Law ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Spectral Feature ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Spectral Components ◽  
Short Grbs ◽  
Prompt Emission ◽  
Emission Phase

Abstract A prompt extra power-law (PL) spectral component that usually dominates the spectral energy distribution below tens of keV or above ∼10 MeV has been discovered in some bright gamma-ray bursts (GRBs). However, its origin is still unclear. In this paper, we present a systematic analysis of 13 Fermi short GRBs, as of 2020 August, with contemporaneous keV–MeV and GeV detections during the prompt emission phase. We find that the extra PL component is a ubiquitous spectral feature for short GRBs, showing up in all 13 analyzed GRBs. The PL indices are mostly harder than −2.0, which may be well reproduced by considering the electromagnetic cascade induced by ultrarelativistic protons or electrons accelerated in the prompt emission phase. The average flux of these extra PL components positively correlates with that of the main spectral components, which implies they may share the same physical origin.

scholarly journals A COMPLETE SAMPLE OF BRIGHTSWIFTLONG GAMMA-RAY BURSTS. I. SAMPLE PRESENTATION, LUMINOSITY FUNCTION AND EVOLUTION

2012 ◽  
Vol 749 (1) ◽  
pp. 68 ◽  
Author(s):  
R. Salvaterra ◽  
S. Campana ◽  
S. D. Vergani ◽  
S. Covino ◽  
P. D’Avanzo ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Complete Sample ◽  
Sample Presentation

scholarly journals Gamma Ray Bursts in the Fermi era: the spectral energy distribution of the prompt emission

2010 ◽  
Author(s):  
F. Massaro ◽  
J. E. Grindlay ◽  
A. Paggi ◽  
Nobuyuki Kawai ◽  
Shigehiro Nagataki
Keyword(s):  
Energy Distribution ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Prompt Emission

scholarly journals X-ray flares in early GRB afterglows

2007 ◽  
Vol 365 (1854) ◽  
pp. 1213-1226 ◽  
Author(s):  
D.N Burrows ◽  
A Falcone ◽  
G Chincarini ◽  
D Morris ◽  
P Romano ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Late Time ◽  
Emission Mechanism ◽  
Time Activity ◽  
X Ray ◽  
Central Engine ◽  
Prompt Emission

The Swift X-ray Telescope (XRT) has discovered that flares are quite common in early X-ray afterglows of gamma-ray bursts (GRBs), being observed in roughly 50% of afterglows with prompt follow-up observations. The flares range in fluence from a few per cent to approximately 100% of the fluence of the prompt emission (the GRB). Repetitive flares are seen, with more than four successive flares detected by the XRT in some afterglows. The rise and fall times of the flares are typically considerably smaller than the time since the burst. These characteristics suggest that the flares are related to the prompt emission mechanism, but at lower photon energies. We conclude that the most likely cause of these flares is late-time activity of the GRB central engine.

Sign in / Sign up

Export Citation Format

Share Document