Fermi LAT Monitored Source List: Daily and Weekly Gamma-Ray Fluxes

NASA's Fermi Gamma-ray Space Telescope provides daily and weekly flux measurements for monitored astronomical sources. The data is produced via a 'quick look' analysis to facilitate rapid multi-wavelength follow-up of flaring sources, with updates occurring about once per week. These preliminary flux estimates are released by the NASA HEASARC from tables created by the Fermi Science Support Center.

Use Cases

• Monitoring gamma-ray source activity over time based on daily and weekly flux measurements.
• Identifying and studying flaring events based on the described photon flux threshold of 2x10^-6 photons cm^-2 s^-1.
• Correlating gamma-ray flux changes with observations from other telescopes for multi-wavelength astrophysics.
• Analyzing the temporal behavior of sources until their flux drops below the specified 2x10^-7 photons cm^-2 s^-1 level.

Strengths

• Data is updated approximately weekly, providing relatively current monitoring.
• Includes flux measurements for sources that flare above a specific, defined threshold (2x10^-6 photons cm^-2 s^-1).
• Produced by NASA's Fermi Science Support Center and HEASARC, indicating an authoritative space agency origin.

Limitations

• The description explicitly states the early flux estimates do not include systematic uncertainties and lack absolute flux calibration.
• Source fluxes may have variations of up to 10% due to uncorrected dependencies on particle background.
• Row count and specific column definitions are unknown, limiting pre-download assessment of structure.

Provenance

Source

National Aeronautics and Space Administration (NASA), Fermi Science Support Center (FSSC), HEASARC.

Collection Method

Derived from 'quick look' analysis of Fermi Large Area Telescope (LAT) data by the LAT Instrument Science Operations Center (LISOC).

Time Range

Ongoing daily and weekly monitoring from the Fermi telescope's survey mode.

Freshness

Last metadata update was 2026-03-13; data is updated about once per week.

Geography

Covers the entire sky, as the Fermi telescope observes the whole sky every day.