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"14824 results found.
- EP240913A / GRB 240913C: AstroSat CZTI detection
- GRB 240914A: SVOM/GRM observation
- EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
- EP240913a: EP-WXT detection of a fast X-ray transient
- GRB 240913B: Fermi GBM Final Real-time Localization
- GRB 240912A: Swift/UVOT Detection
- GRB 240912A: SVOM/GRM observation
- GRB 240913A: Fermi GBM Final Real-time Localization
- GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
- GRB 240912A : INTEGRAL SPI ACS LIGHT CURVE
- GRB 240912B: Fermi GBM Final Real-time Localization
- GRB 240912A: Swift detection of a burst with an optical counterpart
- GRB 240912A: Fermi GBM Final Real-time Localization
- GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
- EP240908a: Optical afterglow confirmation
- GRB 240710A: SVOM/GRM observation
- IPN triangulation of GRB 240905B (short)
- GRB 240825A: 7DT Optical Upper Limit
- GRB 240910A: GRBAlpha detection
- GRB 240910B: Fermi GBM Final Real-time Localization
- GRB 240910A: SVOM/GRM observation
- EP240908a: Updates on the WXT detection result around the trigger time
- GRB 240910A: Fermi GBM Final Real-time Localization
- EP240908a: optical afterglow candidate
- EP240908a: EP detection of a fast X-ray transient
- GRB 240908A: Fermi GBM Final Real-time Localization
- GRB 240801A: SVOM/GRM observation
- GRB 240905E: GIT optical upper limit
- GRB 240905B: Fermi-LAT detection
- GRB 240902B: AstroSat CZTI detection of a long burst
- GRB 240902A: AstroSat CZTI detection of a long burst
- GRB 240905E: SVOM/GRM observation
- GRB 240905E: Swift detection of a burst
- GRB 240905D: AstroSat CZTI detection
- GRB 240905A: SVOM/GRM observation
- GRB 240905D: Fermi GBM Final Real-time Localization
- GRB 240905B: AstroSat CZTI detection and localization
- GRB 240905C: Fermi GBM Final Real-time Localization
- GRB 240905B: Fermi GBM Final Real-time Localization
- GRB 240825A: ATCA Detection of Radio Counterpart
- GRB 240905A: Fermi GBM Final Real-time Localization
- GRB 240904A: Swift detection of a burst
- GRB 240828A: SVOM/GRM observation
- GRB 240828A: GECAM detection
- GRB 240831B: Fermi GBM Final Localization
- GRB 240825A: MeerLICHT afterglow detection
- GRB 240821A: VLT spectroscopic observations
- GRB 240829B: GRBAlpha detection
- GRB 240831A: Fermi GBM Final Real-time Localization
- GRB 240825A: MeerKAT detection
- GRB 240829B: Fermi GBM Final Localization
- GRB 240825A: SVOM/VT optical detection
- GRB 240828A: Swift-XRT afterglow detection
- GRB 240828B: Swift-XRT afterglow detection
- GRB 240829A: Swift detection of a burst
- GRB 240828A: Fermi-LAT detection
- GRB 240828A: AstroSat CZTI detection of a long burst
- GRB 240819A as a likely X-Ray Flash
- GRB 240825A: VLA detection
- 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 240825A: PRIME near-infrared detection
- Konus-Wind detection of GRB 240825A (bright/long)
- 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: VLT/X-shooter redshift
- GRB 240825A: Fermi-LAT detection
- GRB 240824B: Fermi GBM Observation
- GRB 240825A: 1.6m Mephisto multi-band detection
- GRB 240825A: AKO Optical Afterglow Detection
- GRB 240825A: Skynet Optical Afterglow observations
- GRB 240825A: Swift detection of a burst with a bright optical counterpart
- GRB 240825A: Fermi GBM Final Real-time Localization
- GRB 240824B: Swift-XRT afterglow detection
- GRB 240824C: Fermi GBM Final Localization
- GRB 240824B: MAXI/GSC detection
- GRB 240824B: Fermi GBM Final Real-time Localization
- GRB 240824A: Retraction of GCN 37255
- GRB 240824A: Swift detection of a burst
- EP240820a: PRIME J-band Observations
- GRB 240822A: AstroSat CZTI detection of a short burst
- GRB 240821A: LCO optical observations
- GRB 240821A: SVOM/VT follow-up and optical upper limit
- GRB 240821A: GMG Optical Upper Limit
- GRB 240821A: Fermi GBM Observation
- GRB240821A: EIRSAT-1 GMOD Detection
- GRB240821B: First GRB Detected by EIRSAT-1 GMOD
- GRB 240821A: EP-FXT follow-up observation and afterglow candidates
- EP240801a: Keck/LRIS spectroscopic redshift confirmation
- GRB 240821A: SVOM/GRM observation
- GRB 240821A: SVOM/GRM observation
- GRB 240821B: Fermi GBM Final Localization
- Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73