The Fermi All-sky Variability Analysis: A list of flaring gamma-ray sources and the search for transients in our Galaxy

TL;DR

The paper introduces FAVA, a systematic tool for analyzing gamma-ray sky variability using Fermi LAT data, identifying 215 flaring sources and exploring their Galactic or extragalactic origins.

Contribution

FAVA provides a novel systematic approach to detect and catalog gamma-ray variability and flaring sources across the entire sky.

Findings

Identified 215 flaring gamma-ray sources.

Most low-latitude sources are likely extragalactic.

Demonstrated effectiveness of weekly variability analysis.

Abstract

In this paper we present the Fermi All-sky Variability Analysis (FAVA), a tool to systematically study the variability of the gamma-ray sky measured by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. For each direction on the sky, FAVA compares the number of gamma rays observed in a given time window to the number of gamma rays expected for the average emission detected from that direction. This method is used in weekly time intervals to derive a list of 215 flaring gamma-ray sources. We proceed to discuss the 27 sources found at Galactic latitudes smaller than 10 degrees and show that, despite their low latitudes, most of them are likely of extragalactic origin.