FERMIGTRIG ivo://nasa.heasarc/fermigtrig NASA/GSFC HEASARC HEASARC 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Transient This table lists all of the triggers observed by one or more of the 14 GBM detectors (12 NaI and 2 BGO). Note that there are two Browse catalogs resulting from GBM triggers. All GBM triggers are entered in the Trigger Catalog, but only those triggers classified as bursts are entered in the <a href="/W3Browse/fermi/fermigbrst.html">Fermi GBM Burst Catalog</a>. Thus, a burst will be found in both the Trigger and Burst Catalogs. The Burst Catalog analysis requires human intervention; therefore, GRBs will be entered in the Trigger Catalog before the Burst Catalog. The latency requirements are 1 day for triggers and 3 days for bursts. The GBM consists of an array of 12 sodium iodide (NaI) detectors which cover the lower end of the energy range up to 1 MeV. The GBM triggers off of the rates in the NaI detectors, with some Terrestrial Gamma-ray Flash (TGF)-specific algorithms using the bismuth germanate (BGO) detectors, sensitive to higher energies, up to 40 MeV. The NaI detectors are placed around the Fermi spacecraft with different orientations to provide the required sensitivity and FOV. The cosine-like angular response of the thin NaI detectors is used to localize burst sources by comparing rates from detectors with different viewing angles. The two BGO detectors are placed on opposite sides of the spacecraft so that all sky positions are visible to at least one BGO detector. The signals from all 14 GBM detectors are collected by a central Data Processing Unit (DPU). This unit digitizes and time-tags the detectors' pulse height signals, packages the resulting data into several different types for transmission to the ground (via the Fermi spacecraft), and performs various data processing tasks such as autonomous burst triggering. The information in this table is provided by the Fermi Gamma-ray Burst Monitor Instrument Operations Center (GIOC) and the Fermi Science Support Center (FSSC). The values come from a trigger catalog entry file or a burst catalog entry file provided by the GIOC. These are FITS files which may contain additional data in extensions for bursts (see the spectrum_flag and fit_flag columns) and are available for download. This table is updated automatically within a day or so of new data files being processed and made available. This is a service provided by NASA HEASARC . https://heasarc.gsfc.nasa.gov/W3Browse/all/fermigtrig.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=fermigtrig& GET text/xml 180 99999 true 195 -89.4167 3 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=fermigtrig GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_fermigtrig&Action=More+Options&Action=Parameter+Search&ConeAdd=1 FERMI 3 Gamma-ray public fermigtrig Fermi GBM Trigger Catalog version Current Version of the Catalog Entry File meta.version short nullable trigger_name Fermi Trigger Designation (Assigned for Each New Trigger Detected) meta.id;meta.main char nullable name Source Designation meta.id char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable trigger_time Observation Trigger Time mjd time.epoch;obs double nullable trigger_type Classification of Trigger char nullable reliability Probability of the Trigger Classification, As Assigned by GBM Flight Software double nullable trigger_timescale Timescale (in milliseconds) That Actually Produced the Trigger ms short nullable "time" Observation Start Time mjd time.start;obs double nullable error_radius Uncertainty in the Position (degrees) degree stat.error;pos double nullable theta Angle of Best Localization to the LAT Boresight (degrees) degree double nullable adc_high Highest Detected Energy Channel After Analog-Digital Conversion (0 - 4095) short nullable geo_lat Spacecraft Geographical East Longitude (degrees) degree double nullable bii Galactic Latitude degree pos.galactic.lat double nullable adc_low Lowest Detected Energy Channel After Analog-Digital Conversion (0 - 4095) short nullable localization_source Source Used for Localization Coordinates char nullable end_time Observation End Time mjd time.end;obs double nullable detector_mask Flags [01] Indicate Triggered Detectors by Position char nullable phi Angle of Best Localization in Azimuth +X Axis Toward +Y (degrees) degree double nullable ra_scx Right Ascension of the Pointing of the Spacecraft X-Axis (J2000 degrees) degree double nullable trigger_algorithm Number of the Trigger Algorithm Used by the GBM Flight Software short nullable channel_low Lowest Energy Channel in Which the Trigger Was Detected short nullable ra_scz Right Ascension of the Pointing of the Spacecraft Z-Axis (J2000 degrees) degree double nullable dec_scz Declination of the Pointing of the Spacecraft Z-Axis (J2000 degrees) degree double nullable lii Galactic Longitude degree pos.galactic.lon double nullable geo_long Spacecraft Geographical North Latitude (degrees) degree double nullable dec_scx Declination of the Pointing of the Spacecraft X-Axis (J2000 degrees) degree double nullable channel_high Highest Energy Channel in Which the Trigger Was Detected short nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable