Anomalies in the GRB spatial distribution

TL;DR

This paper investigates the spatial distribution of gamma-ray bursts detected by Swift, revealing an increasingly pronounced clustering at redshift around 2, which may suggest large-scale universal structure.

Contribution

It provides an updated analysis of gamma-ray burst clustering at z~2, showing the cluster is more prominent with additional data, indicating potential large-scale anisotropies.

Findings

Increased clustering at redshift z~2 compared to previous reports.

Clustering is more pronounced with additional gamma-ray burst data.

Supports the hypothesis of large-scale universal structure.

Abstract

Swift's remarkable ability to quickly localize gamma-ray bursts has led to the accumulation of a sizable burst sample for which both angular locations and redshifts are measured. This sample has become large enough that it can potentially be used to probe angular anisotropies indicative of large-scale universal structure. In a previous work, a large clustering of gamma-ray bursts at redshift z about 2 was reported in the general direction of the constellations of Hercules and Corona Borealis. Since that report, a 42 per cent increase in the number of z about 2 gamma-ray bursts has been observed, warranting an updated analysis. Surprisingly, the cluster is more pronounced now than it was when it was first reported.