Fermi LAT 3FGL: 4-Year Gamma-Ray Point Source Catalog

The Fermi LAT 4-Year Point Source Catalog (3FGL) contains high-energy gamma-ray sources detected by the Fermi Gamma-ray Space Telescope's Large Area Telescope. It covers the first 48 months of the mission, from 2008 August 4, with sources characterized in the 100 MeV to 300 GeV range. The catalog was produced by the Fermi LAT Team and is provided by NASA HEASARC.

Use Cases

• Classifying gamma-ray source populations based on spectral fits and flux measurements.
• Cross-matching and associating LAT sources with counterparts in other astronomical catalogs.
• Analyzing spectral curvature of sources using power-law, log-parabola, and exponential cutoff models.
• Studying the sensitivity of source detection to models of Galactic diffuse gamma-ray emission.

Strengths

• Incorporates twice as much data as the previous 2FGL catalog.
• Includes analysis improvements like improved calibrations and an updated Galactic diffuse emission model.
• Provides source location regions as elliptical fits to 95% confidence regions.
• Contains flux measurements in 5 energy bands for each source.

Limitations

• This catalog (3FGL) has been superseded by the 8-Year Point Source Catalog (4FGL).
• Column-level documentation is absent; field semantics must be inferred after download.
• Some sources at low Galactic latitudes are flagged as having positions strongly dependent on the diffuse emission model.

Provenance

Source

NASA Fermi Science Support Center (FSSC) and NASA HEASARC.

Collection Method

Data collected by the Fermi Gamma-ray Space Telescope's Large Area Telescope.

Time Range

First 48 months of the science mission, beginning 2008 August 4.

Freshness

Last updated 2026-03-13 18:00:36.656452; freshness should be verified as the catalog is superseded.

Geography

All-sky observations.