Short Gamma-Ray Bursts with Extended Emission Observed with Swift/BAT and Fermi/GBM

TL;DR

This study systematically identifies and analyzes short gamma-ray bursts with extended emission using Swift/BAT and Fermi/GBM data, revealing correlations and discussing potential progenitor models.

Contribution

It provides the first comprehensive catalog and analysis of short GRBs with extended emission from multiple detectors, highlighting their properties and possible origins.

Findings

Identified 30 GRBs with extended emission from Swift/BAT and Fermi/GBM data.

Discovered strong correlations among spectral and temporal parameters.

Compared properties with previous BATSE observations, suggesting a two-component jet progenitor scenario.

Abstract

Some short GRBs are followed by longer extended emission, lasting anywhere from ~10 to ~100 s. These short GRBs with extended emission (EE) can possess observational characteristics of both short and long GRBs (as represented by GRB 060614), and the traditional classification based on the observed duration places some of them in the long GRB class. While GRBs with EE pose a challenge to the compact binary merger scenario, they may therefore provide an important link between short and long duration events. To identify the population of GRBs with EE regardless of their initial classifications, we performed a systematic search of short GRBs with EE using all available data (up to February 2013) of both Swift/BAT and Fermi/GBM. The search identified 16 BAT and 14 GBM detected GRBs with EE, several of which are common events observed with both detectors. We investigated their spectral and temporal properties for both the spikes and the EE, and examined correlations among these parameters. Here we present the results of the systematic search as well as the properties of the identified events. Finally, their properties are also compared with short GRBs with EE observed with BATSE, identified through our previous search effort. We found several strong correlations among parameters, especially when all of the samples were combined. Based on our results, a possible progenitor scenario of two-component jet is discussed.