Fermi Large Area Telescope Fourth Source Catalog
(2019)cite arxiv:1902.10045Comment: Second release with SEDs and light curves; high-resolution version at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/8yr_catalog/. arXiv admin note: text overlap with arXiv:1501.02003.Abstract
We distribute a new release of the fourth Fermi Large Area Telescope source
catalog (4FGL) containing spectral energy distributions averaged over 8 years
and light curves with 1-year intervals. This supersedes the FL8Y source list
distributed in 2018. Based on the first eight years of science data from the
Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1
TeV, it is the deepest yet in this energy range. Relative to the 3FGL catalog,
the 4FGL catalog has twice as much exposure as well as a number of analysis
improvements, including an updated model for the Galactic diffuse gamma-ray
emission. The 4FGL catalog includes 5065 sources above 4 sigma significance,
for which we provide localization and spectral properties. Seventy-five sources
are modeled explicitly as spatially extended, and overall 355 sources are
considered as identified based on angular extent, periodicity or correlated
variability observed at other wavelengths. For 1323 sources we have not found
plausible counterparts at other wavelengths. More than 3130 of the identified
or associated sources are active galaxies of the blazar class, and 239 are
pulsars.
Description
Fermi Large Area Telescope Fourth Source Catalog