GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- GRB240828B: REM optical/NIR upper limits
- Fermi trigger No 746816563: Global MASTER-Net observations report
- GRB 240828B: AbAO optical upper limit
- GRB 240831A: Fermi GBM Final Real-time Localization
- GRB 240825A: SOAR observations
- GRB 240828B: Mephisto optical upper limit
- GRB 240828B: GRANDMA Optical Upper Limit
- LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
- GRB 240829A: Swift-BAT refined analysis
- GRB 240825A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
- GRB 240825A: MeerKAT detection
- GRB 240828B: J-band upper limit from WINTER
- Fermi trigger No 746684112: Global MASTER-Net observations report
- GRB 240828B: GMG Optical Upper Limit
- GRB 240828A: KAIT continued optical observations
- GRB 240828B: GWAC-F50A optical upper limit
- GRB 240828B: SVOM/C-GFT optical upper limit
- GRB 240828B: SAO RAS optical upper limit
- GRB 240828B: KAIT optical upper limit
- GRB 240828A: SAO RAS optical observations
- Fermi trigger No 746587425: Global MASTER-Net observations report
- GRB 240829B: Fermi GBM Final Localization
- GRB 240828A: Fermi GBM Observation
- GRB 240629A: First GRB Detected by BurstCube
- GRB 240828A: KAIT Optical Afterglow Candidate
- GRB 240825A: SVOM/VT optical detection
- GRB 240828A: Swift-XRT afterglow detection
- GRB 240825A: further SAO RAS optical observations
- GRB 240825A: iTelescope optical observations
- GRB 240828B: Swift-XRT afterglow detection
- GRB 240829A: Swift detection of a burst
- Swift GRB240829.16: Global MASTER-Net observations report
- GRB 240828A: Fermi-LAT detection
- GRB 240828A: Tiled Swift observations
- LAT GRB240828.62: Global MASTER-Net observations report
- GRB 240828A: AstroSat CZTI detection of a long burst
- Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
- GRB 240825A: Upper limits from a neutrino search with IceCube
- GRB 240819A as a likely X-Ray Flash
- GRB 240828B: Swift ToO observations
- GRB 240821A: PRIME near-infrared observations
- GRB 240825A: VLA detection
- Fermi GRB 240828A: Global MASTER-Net observations report
- Fermi trigger No 746438824: Global MASTER-Net observations report
- SVOM GRB 240821A: optical afterglow discovery
- GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
- GRB 240828A: Fermi GBM Final Real-time Localization
- GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
- GRB 240825A: GECAM detection
- GRB 240825A: ALMA detection
- GRB 240825A: SAO RAS optical observations
- GRB 240824A: GIT optical upper limit
- GRB 240819A: Swift afterglow confirmation
- GRB 240825A: TNG optical photometry and spectroscopy
- LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
- LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
- GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
- GRB 240825A: GMG Continued Optical Observation on the Second Night
- GRB 240824B: Ondrejov D50 optical limit
- GRB 240825A: KAIT optical observations
- GRB 240825A: PRIME near-infrared detection
- Konus-Wind detection of GRB 240825A (bright/long)
- GRB 240825A: Fermi GBM Observation
- GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
- GRB 240825A: AKO Optical Follow-Up Observations
- GRB 240825A: AstroSat CZTI detection of the long bright burst
- SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
- GRB 240825A: Swift/UVOT Detection
- GRB 240825A: REM detection of the optical/NIR afterglow
- GRB 240825A: Swift-XRT refined Analysis
- GRB 240825A: VLT/X-shooter redshift
- GRB 240825A: SVOM/C-GFT optical observations
- GRB 240825A: Montarrenti Observatory optical observations
- GRB 240825A: Enhanced Swift-XRT position
- GRB 240825A: MASTER optical counterpart observation
- GRB 240825A: Fermi-LAT detection
- GRB 240825A: LCO optical observations
- GRB 240824B: KAIT optical upper limit
- SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
- GRB 240824B: Fermi GBM Observation
- Fermi GRB 240825A: Global MASTER-Net observations report
- SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
- GRB 240824B: NOT optical upper limit
- GRB 240825A: GMG Optical Observation
- Swift GRB 240825A: Global MASTER-Net observations report
- GRB 240825A: 1.6m Mephisto multi-band detection
- GRB 240825A: AKO Optical Afterglow Detection
- GRB 240825A: Skynet Optical Afterglow observations
- GRB 240825A: Nanshan/HMT optical afterglow observations
- GRB 240825A: Swift detection of a burst with a bright optical counterpart
- GRB 240825A: Fermi GBM Final Real-time Localization
- GRB 240824A: Swift-BAT refined analysis
- GRB 240824A: SVOM/C-GFT optical upper limit
- GRB 240824B: Swift-XRT afterglow detection
- GRB 240824A: Swift-XRT observations
- LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
- GRB 240824B: Swift/BAT arcminute localization of a burst
- GRB 240824B: Swift ToO observations