A Remarkable Angular Distribution of the Intermediate Subclass of Gamma‐Ray Bursts

Mészáros, A.; Bagoly, Z.; Horváth, I.; Balázs, L. G.; Vavrek, R.

doi:10.1086/309193

Cited by 65 publications

(74 citation statements)

References 19 publications

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“…However, the physical existence of the third group is still argueable. The sky distribution of the third component is anisotropic as proven by Balázs et al (1998), Balázs et al (1999), Mészáros et al (2000), Litvin et al (2001). The log N− log S distribution may also differ from the other group's distributions (Horváth 1998).…”

Section: Discussionmentioning

confidence: 90%

See 1 more Smart Citation

A further study of the BATSE Gamma-Ray Burst duration distribution

Horváth¹

2002

A&A

111

139

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Abstract. Two classes of gamma-ray bursts have been identified so far, characterized by durations shorter and longer than about 2 s. In 1998 two independent papers indicated the existence of the third class of the bursts with duration between approximately 2 and 10 s. In this paper, using the full BATSE Catalog, the maximum likelihood estimation is presented, which gives a 0.5% probability for having only two subclasses. A Monte-Carlo simulation also confirms this probability.

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Section: Discussionmentioning

confidence: 90%

“…Further, the intermediate subgroup shows a remarkable angular distribution on the sky (Balázs et al 1998;Balázs et al 1999;Mészáros et al 2000;Litvin et al 2001 the existence of this subgroup is a matter of debate. Hence additional studies concerning this subclass are highly desireable.…”

Section: Introductionmentioning

confidence: 99%

A further study of the BATSE Gamma-Ray Burst duration distribution

Horváth¹

2002

A&A

111

139

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“…As a further test, we compare the distribution of the dimmer intermediate bursts with that of the long bursts, because this pair of distributions were found by Mészáros et al (2000) to exhibit the strongest difference. To do this, we select the fainter 50% of the bursts, defined as those bursts with a fluence in the 15−25 keV band lower or equal to the median value of all the intermediate bursts (the same result is obtained by using the 50−100 keV band).…”

Section: Redshift Distributionmentioning

confidence: 99%

Searching for differences inSwift’s intermediate GRBs

Postigo

Horváth²,

Vereš

et al. 2010

A&A

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Context. Gamma-ray bursts are usually classified in terms their high-energy emission into either short-duration or long-duration bursts, which presumably reflect two different types of progenitors. However, it has been shown on statistical grounds that a third, intermediate population is needed in this classification scheme, although an extensive study of the properties of this class has so far not been performed. The large amount of follow-up studies generated during the Swift era allows us to have a sufficient sample to attempt a study of this third population through the properties of their prompt emission and their afterglows. Aims. To understand the differences of the intermediate population, we study a sample of GRBs observed by Swift during its first four years of operation. The sample contains only bursts with measured redshifts since these data help us to derive intrinsic properties. Methods. We search for differences in the properties of the three groups of bursts, which we quantify using a Kolmogorov-Smirnov test whenever possible. Results. Intermediate bursts are found to be less energetic and have dimmer afterglows than long GRBs, especially when considering the X-ray light curves, which are on average one order of magnitude fainter than long bursts. There is a less significant trend in the redshift distribution that places intermediate bursts closer than long bursts. Except for this, intermediate bursts show similar properties to long bursts. In particular, they follow the E peak versus E iso correlation and have, on average, positive spectral lags with a distribution similar to that of long bursts. As for long GRBs, they normally have an associated supernova, although some intermediate bursts have been found to contain no supernova component. Conclusions. This study shows that intermediate bursts differ from short bursts, but exhibit no significant differences from long bursts apart from their lower brightness. We suggest that the physical difference between intermediate and long bursts could be explained by being produced by similar progenitors, of the former being the ejecta thin shells and the latter thick shells.

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“…The large-scale angular isotropy of the sky distribution of GRBs has been well studied over the last few decades. Most of these studies have demonstrated that the sky distribution of GRBs is isotropic Tegmark et al 1996;Balázs et al 1998Balázs et al , 1999Mészáros et al 2000;Magliocchetti et al 2003;Vavrek et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Possible structure in the GRB sky distribution at redshift two

Horváth

Hakkila

Bagoly

2014

A&A

Self Cite

120

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Context. Research over the past three decades has revolutionized cosmology while supporting the standard cosmological model. However, the cosmological principle of Universal homogeneity and isotropy has always been in question, since structures as large as the survey size have always been found each time the survey size has increased. Until 2013, the largest known structure in our Universe was the Sloan Great Wall, which is more than 400 Mpc long located approximately one billion light years away. Aims. Gamma-ray bursts (GRBs) are the most energetic explosions in the Universe. As they are associated with the stellar endpoints of massive stars and are found in and near distant galaxies, they are viable indicators of the dense part of the Universe containing normal matter. The spatial distribution of GRBs can thus help expose the large scale structure of the Universe. Methods. As of July 2012, 283 GRB redshifts have been measured. Subdividing this sample into nine radial parts, each containing 31 GRBs, indicates that the GRB sample having 1.6 < z < 2.1 differs significantly from the others in that 14 of the 31 GRBs are concentrated in roughly 1/8 of the sky. A two-dimensional Kolmogorov-Smirnov test, a nearest-neighbour test, and a Bootstrap Point-Radius Method explore the significance of this clustering. Results. All tests used indicate that there is a statistically significant clustering of the GRB sample at 1.6 < z < 2.1. Furthermore, this angular excess cannot be entirely attributed to known selection biases, making its existence due to chance unlikely. Conclusions. This huge structure lies ten times farther away than the Sloan Great Wall, at a distance of approximately ten billion light years. The size of the structure defined by these GRBs is about 2000-3000 Mpc, or more than six times the size of the largest known object in the Universe, the Sloan Great Wall.

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A Remarkable Angular Distribution of the Intermediate Subclass of Gamma‐Ray Bursts

Cited by 65 publications

References 19 publications

A further study of the BATSE Gamma-Ray Burst duration distribution

A further study of the BATSE Gamma-Ray Burst duration distribution

Searching for differences inSwift’s intermediate GRBs

Possible structure in the GRB sky distribution at redshift two

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