scholarly journals Gamma-ray bursts from stellar remnants: probing the Universe at high redshift

1998 ◽  
Vol 294 (1) ◽  
pp. L13-L17 ◽  
Author(s):  
R. A. M. J. Wijers ◽  
J. S. Bloom ◽  
J. S. Bagla ◽  
P. Natarajan
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
The Universe

scholarly journals Observations of GRBs at high redshift

2007 ◽  
Vol 365 (1854) ◽  
pp. 1377-1384 ◽  
Author(s):  
Nial R Tanvir ◽  
Páll Jakobsson
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Gamma Ray Bursts ◽  
Star Formation History ◽  
Redshift Distribution ◽  
Formation History ◽  
History Of ◽  
The Universe

The extreme luminosity of gamma-ray bursts and their afterglows means they are detectable, in principle, to very high redshifts. Although the redshift distribution of gamma-ray bursts (GRBs) is difficult to determine, due to incompleteness of present samples, we argue that for Swift-detected bursts, the median redshift is between 2.5 and 3, with a few per cent probably at z >6. Thus, GRBs are potentially powerful probes of the era of reionization and the sources responsible for it. Moreover, it seems probable that they can provide constraints on the star-formation history of the Universe and may also help in the determination of the cosmological parameters.

scholarly journals Constraining the anisotropy of the universe from supernovae and gamma-ray bursts

2014 ◽  
Vol 29 (15) ◽  
pp. 1450067 ◽  
Author(s):  
Zhe Chang ◽  
Xin Li ◽  
Hai-Nan Lin ◽  
Sai Wang
Keyword(s):  
Cosmological Model ◽  
Coordinate System ◽  
Gamma Ray ◽  
Line Element ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
Anisotropic Cosmological Model ◽  
Isotropic Cosmological Model ◽  
The Universe ◽  
Friedmann Robertson Walker

Recently, an anisotropic cosmological model was proposed. An arbitrary one-form, which picks out a privileged axis in the universe, was added to the Friedmann–Robertson–Walker (FRW) line element. The distance-redshift relation was modified such that it is direction-dependent. In this paper, we use the Union2 dataset and 59 high-redshift gamma-ray bursts (GRBs) to give constraints on the anisotropy of the universe. The results show that the magnitude of anisotropy is about D = -0.044±0.018, and the privileged axis points toward the direction (l0, b0) = (306.1°±18.7°, -18.2°±11.2°) in the galactic coordinate system. The anisotropy is small and the isotropic cosmological model is an excellent approximation.

scholarly journals Kinematic constraints beyond z ≃ 0 using calibrated GRB correlations

2020 ◽  
Vol 641 ◽  
pp. A174
Author(s):  
Orlando Luongo ◽  
Marco Muccino
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Systematic Errors ◽  
Gamma Ray Bursts ◽  
Auxiliary Variables ◽  
Confidence Levels ◽  
History Of ◽  
Standard Cosmological Model ◽  
Model Independent ◽  
The Universe

Context. The dynamics of the Universe are revised using high-redshift data from gamma-ray bursts to constrain cosmographic parameters by means of model-independent techniques. Aims. Considering samples from four gamma-ray burst correlations and two hierarchies up to j0 and s0, respectively, we derived limits over the expansion history of the Universe. Since cosmic data span outside z ≃ 0, we investigated additional cosmographic methods such as auxiliary variables and Padé approximations Methods. Beziér polynomials were employed to calibrate our correlations and heal the circularity problem. Several Markov chain Monte Carlo simulations were performed on the model-independently calibrated Amati, Ghirlanda, Yonetoku, and combo correlations to obtain 1 − σ and 2 − σ confidence levels and to test the standard cosmological model. Results. Reasonable results are found up to j0 and s0 hierarchies, respectively, only partially alleviating the tension on local H0 measurements as j0 hierarchy is considered. Discussions on systematic errors have been extensively reported here. Conclusions. Our findings show that the ΛCDM model is not fully confirmed using gamma-ray bursts. Indications against a genuine cosmological constant are summarized and commented on in detail.

scholarly journals Gamma‐Ray Bursts as a Probe of the Very High Redshift Universe

2000 ◽  
Vol 536 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Donald Q. Lamb ◽  
Daniel E. Reichart
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
High Redshift Universe ◽  
Very High

Swift observations of gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1119-1128 ◽  
Author(s):  
Neil Gehrels
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
Nearby Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
Other Information ◽  
Short Grbs

Since its launch on 20 November 2004, the Swift mission has been detecting approximately 100 gamma-ray bursts (GRBs) each year, and immediately (within approx. 90 s) starting simultaneous X-ray and UV/optical observations of the afterglow. It has already collected an impressive database, including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows and a rapid follow-up by other observatories notified through the GCN. Advances in our understanding of short GRBs have been spectacular. The detection of X-ray afterglows has led to accurate localizations and the conclusion that short GRBs can occur in non-star-forming galaxies or regions, whereas long GRBs are strongly concentrated within the star-forming regions. This is consistent with the NS merger model. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z ∼5–6, are approaching the era of reionization. Ground-based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to a much greater distance than other techniques. The localization of GRB 060218 to a nearby galaxy, and the association with SN 2006aj, added a valuable member to the class of GRBs with detected supernova.

Gamma-Ray Bursts as Probes of the Universe

2011 ◽  
Author(s):  
Joshua S. Bloom
Keyword(s):  
Star Formation ◽  
Cosmic Rays ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Ongoing Study ◽  
Observable Universe ◽  
History Of ◽  
Expansion Of The Universe ◽  
The Universe

This chapter focuses on how gamma-ray bursts (GRBs) are emerging as unique tools in the study of broad areas of astronomy and physics by virtue of their special properties. The unassailable fact about GRBs that makes them such great probes is that they are fantastically bright and so can be seen to the farthest reaches of the observable Universe. In parallel with the ongoing study of GRB events and progenitors, new lines of inquiry have burgeoned: using GRBs as unique probes of the Universe in ways that are almost completely divorced from the nature of GRBs themselves. Topics discussed include studies of gas, dust, and galaxies; the history of star formation; measuring reionization and the first objects in the universe; neutrinos, gravitational waves, and cosmic rays; quantum gravity and the expansion of the universe; and the future of GRBs.

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