The Fermi-GBM 3-year X-ray Burst Catalog

TL;DR

This paper presents a 3-year catalog of 1084 X-ray bursts detected by Fermi-GBM, classifying them into thermonuclear, accretion, and untriggered gamma-ray bursts, with analysis of their properties and recurrence times.

Contribution

It provides the first comprehensive catalog of Galactic X-ray bursts detected by Fermi-GBM over three years, including spectral and spatial analysis.

Findings

1084 X-ray bursts cataloged and classified

Average of 1.4 PRE bursts per day within 10 kpc

Detection of bursts from specific ultra-compact X-ray binaries

Abstract

The Fermi Gamma Ray Burst Monitor (GBM) is an all sky gamma-ray monitor well known in the gamma-ray burst community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In March 2010, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a 3 year catalog of 1084 X-ray bursts. Using spectral analysis, location and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient events from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expanison (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U~0614+09 and 2S~0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.