A tool to estimate the Fermi Large Area Telescope background for short-duration observations

TL;DR

This paper introduces a new background estimation tool for the Fermi LAT that accurately accounts for changing observational conditions during short-duration astrophysical observations.

Contribution

The paper presents a publicly available tool that improves background estimation accuracy for short Fermi LAT observations by incorporating dynamic observational parameters.

Findings

Accurately estimates LAT background during rapid spacecraft reorientations

Supports analysis of short-duration events like Gamma Ray Bursts

Enhances data analysis reliability for variable observational conditions

Abstract

The proper estimation of the background is a crucial component of data analyses in astrophysics, such as source detection, temporal studies, spectroscopy, and localization. For the case of the Large Area Telescope (LAT) on board the Fermi spacecraft, approaches to estimate the background for short (less than ~one thousand seconds duration) observations fail if they ignore the strong dependence of the LAT background on the continuously changing observational conditions. We present a (to be) publicly available background-estimation tool created and used by the LAT Collaboration in several analyses of Gamma Ray Bursts. This tool can accurately estimate the expected LAT background for any observational conditions, including, for example, observations with rapid variations of the Fermi spacecraft's orientation occurring during automatic repointings.