A Monte Carlo Study of the Irreducible Background in the EGRET Instrument

TL;DR

This study uses Monte Carlo simulations to estimate the irreducible instrumental background in gamma-ray observations, impacting the accuracy of the extragalactic gamma-ray background measurements.

Contribution

It introduces a simulation-based approach to quantify the instrumental background in gamma-ray telescopes, refining previous estimates of the extragalactic gamma-ray background.

Findings

Estimated the magnitude of the irreducible instrumental background

Assessed the impact on current EGRB measurements

Provided preliminary results for future gamma-ray observations

Abstract

The diffuse extragalactic gamma-ray background (EGRB) has been derived by various groups from observations by the Energetic Gamma Ray Experiment Telescope (EGRET) instrument on the Compton Gamma Ray Observatory (CGRO). The derived EGRB consists of gamma rays that may come from astrophysical components, such as from unresolved extragalactic point sources (blazars, normal galaxies, etc.), true extragalactic diffuse emission, misattributed diffuse signals from the Galaxy and other celestial sources, and an irreducible instrumental background due to gamma rays produced by cosmic-ray (CR) interactions in the EGRET instrument. Using the Gamma Ray Large Area Space Telescope (GLAST) simulation and reconstruction software, we have investigated the magnitude of the irreducible instrumental background in the GLAST Large Area Telescope. We re-scale our results to the EGRET and present preliminary results of our study and its effect on current estimates of the EGRB.