Fermi LAT Long-Term Transient Source Catalog: 142 Monthly-Detected Gamma-Ray Sources

The Fermi LAT Long-Term Transient Source Catalog contains 142 unique transient sources detected by the Fermi Large Area Telescope on monthly time intervals. NASA HEASARC ingested this catalog in September 2021, based on data from the Space Science Data Center. The catalog focuses on extragalactic regions and lists sources with a statistical significance above 4 sigma in at least one monthly bin.

Use Cases

• Identify and analyze monthly gamma-ray variability patterns based on the catalog's transient source detections.
• Cross-match transient sources with other astronomical catalogs based on the extragalactic sky coverage mentioned in the description.
• Study the population and characteristics of high-significance (4 sigma) transient events based on the catalog's selection criteria.
• Apply time-series analysis methods to the monthly detection intervals described for the catalog sources.

Strengths

• Contains 142 unique transient sources, providing a specific population for study.
• Sources were detected with a statistical significance above 4 sigma, indicating a high-confidence sample.
• Data is provided by NASA HEASARC and originates from the Fermi Large Area Telescope, a major space observatory.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• The search was limited to extragalactic regions, excluding potential transient sources at low Galactic latitudes.

Provenance

Source

National Aeronautics and Space Administration (NASA), Space Science Data Center (SSDC), NASA HEASARC.

Collection Method

Monthly datasets analyzed using a wavelet-based source detection algorithm, followed by standard Fermi-LAT maximum likelihood analysis.

Time Range

Covers monthly time intervals during Fermi-LAT operations (specific dates not provided).

Freshness

Last updated 2026-03-13 18:59:04.652091; freshness should be verified.

Geography

Extragalactic regions of the sky.