GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"11528 results found.
- Fermi GRB 251214A: Global MASTER-Net observations report
- GRB 251214A: Fermi GBM Final Real-time Localization
- GRB 251211B: AstroSat CZTI detection
- GRB 251209A: NuSTAR detection of prompt emission
- Fermi-LAT Gamma-ray Observations of IceCube-251210A
- Fermi GRB 251211B: Global MASTER-Net observations report
- GRB 251211B: Fermi GBM Final Real-time Localization
- GRB 251211A: Fermi GBM Final Real-time Localization
- GRB 251209A: Fermi GBM observation
- GRB 251209A: AstroSat CZTI detection
- IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 251208A: AstroSat CZTI detection
- Fermi GBM Sub-Threshold Detection of GRB 251205A
- GRB 251208A: Glowbug gamma-ray detection
- GRB 251208B: COLIBRÍ optical upper limits
- GRB 251208C: GECAM-B observation of a short burst
- GRB 251208A: GECAM-B observation of a short burst
- Fermi GRB 251209A: Global MASTER-Net observations report
- Fermi GRB 251208C: Global MASTER-Net observations report
- GRB 251208B: Swift-XRT afterglow detection
- GRB 251209A: Fermi GBM Final Real-time Localization
- GRB 251208B: Fermi GBM Observation
- GRB 251208B: GROWTH-India Telescope optical upper limits
- GRB 251208A: SVOM/GRM observation of a short burst
- GRB 251208C: SVOM/GRM observation of a short burst
- GRB 251208B: Swift ToO observations
- GRB 251208B: Fermi-LAT detection
- GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
- GRB 251208C: Fermi GBM Final Real-time Localization
- GRB 251208B: Fermi GBM Final Real-time Localization
- GRB 251208A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 251118A
- GRB 251126B: Fermi GBM Final Localization
- GRB 251203A: Insight-HXMT/HE detection
- GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
- GRB 251202A: SVOM/GRM observation
- GRB 251203A: GECAM-B observation of a burst
- GRB 251203A: SVOM/GRM observation
- GRB 251201B: SALT spectroscopic redshift z = 1.599
- GRB 251203A: AstroSat CZTI detection
- Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
- GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
- GRB 251201B: Insight-HXMT/HE detection
- EP251202a / GRB 251202A: Insight-HXMT/HE detection
- GRB 251203A: Fermi GBM Final Real-time Localization
- EP251202a / GRB251202A: AstroSat CZTI detection
- GRB 251202A / EP251202a: SVOM/VT optical observation
- GRB 251201B: Fermi GBM Observation
- EP251202a/GRB 251202A: KAIT optical observations
- Fermi GRB 251202B: Global MASTER-Net observations report
- GRB 251202B: Fermi GBM Final Real-time Localization
- GRB 251202A: Fermi GBM Observation
- GRB 251201B: Kilonova-Catcher optical afterglow detection
- GRB 251130B: Glowbug gamma-ray detection
- GRB 251201B: GECAM-B observation of a long burst
- Fermi-LAT Gamma-ray Observations of IceCube-251130A
- EP251202a / GRB 251202A: LCO r- and i-band optical detection
- GRB 251202A: GOTO optical afterglow detection
- EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
- Fermi GRB 251202A: Global MASTER-Net observations report
- EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
- GRB 251202A: Fermi GBM Final Real-time Localization
- GRB 251201B: SVOM/VT optical fading
- Swift GRB 251201B : MASTER optical counterpart detection
- GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
- GRB 251130B: AstroSat CZTI detection
- GRB 251201B: Fermi GBM Final Real-time Localization
- Fermi GRB 251130B: Global MASTER-Net observations report
- GRB 251127A: SVOM/GRM observation
- IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 251130B: Fermi GBM Final Localization Correction
- GRB 251130B: Fermi GBM Final Real-time Localization
- GRB 251130A: Fermi GBM Final Real-time Localization
- GRB 251128A: AstroSat CZTI detection
- GRB 251128A: GECAM-B detection
- GRB 251128A: SVOM/GRM observation of a long burst
- GRB 251128A: Insight-HXMT/HE detection
- GRB 251128A: Fermi GBM Observation
- GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
- Fermi GRB 251128A: Global MASTER-Net observations report
- GRB 251127A: Glowbug gamma-ray detection
- GRB 251128A: Fermi GBM Final Real-time Localization
- GRB 251125B: GECAM-B detection
- Fermi GRB 251127A: Global MASTER-Net observations report
- GRB 251127A: Fermi GBM Final Real-time Localization
- GRB 251121A: Fermi GBM Observation
- GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
- GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
- Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
- Fermi GRB 251125B: Global MASTER-Net observations report
- GRB 251125B: Fermi GBM Final Real-time Localization
- Fermi GRB 251125A: Global MASTER-Net observations report
- GRB 251125A: Fermi GBM Final Real-time Localization
- GRB 251124A: Fermi GBM Localization by automated pipeline
- GRB 251122B: Fermi GBM Final Localization
- Fermi GRB 251124a: Global MASTER-Net observations report
- GRB 251124a: Fermi GBM Final Localization
- GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
- GRB 251121A: Glowbug gamma-ray detection of a likely short burst
- GRB 251115A: Fermi GBM Observation