juliensimon/fermi-gbm-triggers

Fermi GBM All-Trigger Catalog

Credit: NASA/JPL-Caltech/STScI/CXC/SAO

Part of the Astronomy Datasets collection on Hugging Face.

Complete catalog of all triggers from the Fermi Gamma-ray Burst Monitor (GBM), sourced from NASA HEASARC. Currently 12,089 triggers (4,249 GRBs, 7,840 non-GRB triggers).

Dataset description

The Fermi GBM detects transient events across the full unocculted sky in the 8 keV to 40 MeV energy range. While the confirmed GRB catalog (fermigbrst) contains only verified gamma-ray bursts, this all-trigger catalog (fermigtrig) includes every trigger the instrument recorded: GRBs, solar flares, soft gamma repeaters (SGRs), terrestrial gamma-ray flashes, particle events, and unclassified triggers.

This broader view is valuable for studying the full population of high-energy transients, training trigger classifiers, and analyzing detection statistics.

The GBM trigger system operates continuously on multiple timescales (16 ms to 4.096 s), flagging statistically significant count-rate increases above background in any of its 12 NaI detectors (8 keV - 1 MeV) or 2 BGO detectors (200 keV - 40 MeV). The resulting trigger population is a rich zoo of astrophysical and non-astrophysical transients. Beyond confirmed GRBs, the catalog contains solar flares (ranging from C-class microflares to X-class events that saturate the detectors), soft gamma repeaters (SGRs) and anomalous X-ray pulsars (magnetars emitting repeated bursts from magnetic field reconfiguration in neutron star crusts), terrestrial gamma-ray flashes (TGFs — millisecond bursts of bremsstrahlung radiation from thunderstorm electrical discharges), Cygnus X-1 flares, and charged particle events from passages through the South Atlantic Anomaly or solar energetic particle events.

The classification of GBM triggers is itself an active area of research. Ground-based analysis refines the initial on-board classification using spectral and temporal properties, localization quality, and coincidence with known sources. Machine learning classifiers trained on this catalog can automate real-time triage of triggers, enabling faster alerts for genuine astrophysical events. The trigger significance, timescale, and localization metadata provide the feature space for such classification tasks, while the human-assigned classifications serve as training labels.

For multi-messenger astrophysics, the complete trigger catalog is essential because sub-threshold events — triggers that fall below the formal GRB detection criteria — can become significant when combined with external coincidences. The landmark GW170817 / GRB 170817A detection demonstrated that even a weak, off-axis GRB can produce a marginal GBM trigger that becomes unambiguous only in the context of a gravitational-wave detection. Systematic searches through this catalog for temporal and spatial coincidences with gravitational-wave candidates, neutrino events, and fast radio bursts are a key component of multi-messenger pipelines.

Schema

Column	Type	Description
__row	mixed	HEASARC column
version	mixed	HEASARC column
trigger_name	mixed	HEASARC column
name	string	Trigger name / identifier
ra	float	Right ascension (degrees)
dec	float	Declination (degrees)
galactic_lon	float	Galactic longitude (degrees)
galactic_lat	float	Galactic latitude (degrees)
error_radius	float	Localization error radius (degrees)
time	mixed	HEASARC column
end_time	mixed	HEASARC column
trigger_time	datetime	Trigger time (UTC, converted from MJD)
trigger_type	string	Trigger classification type
reliability	float	Trigger reliability flag
trigger_timescale	float	Trigger timescale (ms)
trigger_algorithm	mixed	HEASARC column
channel_low	mixed	HEASARC column
channel_high	mixed	HEASARC column
adc_low	mixed	HEASARC column
adc_high	mixed	HEASARC column
detector_mask	mixed	HEASARC column
geo_long	mixed	HEASARC column
geo_lat	mixed	HEASARC column
ra_scx	mixed	HEASARC column
dec_scx	mixed	HEASARC column
ra_scz	mixed	HEASARC column
dec_scz	mixed	HEASARC column
theta	mixed	HEASARC column
phi	mixed	HEASARC column
localization_source	string	Source of localization (e.g. ground, flight)
__x_ra_dec	mixed	HEASARC column
__y_ra_dec	mixed	HEASARC column
__z_ra_dec	mixed	HEASARC column
is_grb	bool	True if trigger is classified as a GRB

Quick stats

• 12,089 triggers (2008-07-14 to 2026-04-04)
• 4,249 classified as GRBs
• 7,840 non-GRB triggers (solar flares, SGRs, particles, etc.)

Trigger type breakdown

• 4,249 GRB
• 2,682 SFLARE
• 1,725 LOCLPAR
• 1,616 TGF
• 788 UNCERT
• 680 SGR
• 214 TRANSNT
• 129 DISTPAR

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/fermi-gbm-triggers", split="train")
df = ds.to_pandas()

# Filter to confirmed GRBs
grbs = df[df["is_grb"] == True]
print(f"{len(grbs):,} GRBs out of {len(df):,} total triggers")

# Non-GRB triggers
non_grb = df[df["is_grb"] == False]
print(non_grb["trigger_type"].value_counts())

# Triggers per year
df["year"] = df["trigger_time"].dt.year
df.groupby("year").size().plot(kind="bar", title="Fermi GBM Triggers per Year")

# Sky map of triggers
import matplotlib.pyplot as plt
plt.scatter(df["ra"], df["dec"], s=1, alpha=0.3)
plt.xlabel("RA (deg)")
plt.ylabel("Dec (deg)")
plt.title("Fermi GBM Trigger Sky Distribution")

Data source

All data comes from the Fermi GBM Trigger Catalog hosted by NASA's High Energy Astrophysics Science Archive Research Center (HEASARC), accessed via the TAP protocol.

Update schedule

Daily at 20:00 UTC via GitHub Actions.

Related datasets

• gamma-ray-bursts — Fermi GBM confirmed GRB Catalog
• fermi-4fgl — Fermi LAT 4FGL Source Catalog
• solar-flare-events — GOES X-ray flare detections

Pipeline

Source code: juliensimon/space-datasets

Support

If you find this dataset useful, please give it a ❤️ on the dataset page and share feedback in the Community tab! Also consider giving a ⭐️ to the space-datasets repo.

Citation

@dataset{fermi_gbm_triggers,
  author = {Simon, Julien},
  title = {Fermi GBM All-Trigger Catalog},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/fermi-gbm-triggers},
  note = {Based on NASA HEASARC Fermi GBM Trigger Catalog data}
}

License

CC-BY-4.0