A statistical classification of the unassociated gamma-ray sources in the second Fermi Large Area Telescope Catalog

TL;DR

This paper uses statistical analysis of known gamma-ray sources to classify the 575 unassociated sources in the Fermi LAT catalog, revealing their likely astrophysical origins.

Contribution

It introduces a method to classify unassociated gamma-ray sources based on their spatial, spectral, and variability properties, improving source identification accuracy.

Findings

Unassociated sources are likely Galactic SNRs/PWNe, BL Lacs, FSRQs, and other active galaxies.

Estimated fractions: 25% SNRs/PWNe, 29% BL Lacs, 41% FSRQs, 5% other AGNs.

Enhanced understanding of gamma-ray source populations.

Abstract

With assistance of the identified/associated sources in the second Fermi Large Area Telescope (LAT) catalog, we analyze and resolve the spatial distribution and the distributions of the gamma-ray spectral and variability indices of the remaining 575 unassociated Fermi LAT sources. Consequently, it is suggested that the unassociated sources could statistically consist of Galactic supernova remnants/pulsar wind nebulae, BL Lacertae objects, flat spectrum radio quasars, and other types of active galaxies with fractions of 25%, 29%, 41%, and 5%, respectively.