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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
3363 results found.
- GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
- Fermi GRB 250128B: Global MASTER-Net observations report
- Fermi GRB 250127B: Global MASTER-Net observations report
- IPN triangulation of GRB 250119C
- GRB 250126A: CALET Gamma-Ray Burst Monitor detection
- GRB 250126A: MAXI/GSC detection
- GRB 250114A: Swift-BAT refined analysis
- GRB 250101A: Terskol Zeiss-2000 optical observations
- EP250111a: Mondy optical observation
- EP250111a: Global MASTER-Net observations report
- GRB 250108B: 1.3m DFOT upper limit
- EP250109a: Global MASTER-Net observations report
- EP250108a: Global MASTER-Net observations report
- Fermi GRB 250107B: Global MASTER-Net observations report
- Fermi trigger No 757753930: Global MASTER-Net observations report
- GRB 250103A: Fermi GBM Observation
- GRB 250103A: SVOM/C-GFT optical upper limit
- GRB 250101A NUTTelA-TAO / BSTI Early Measurements
- GRB 250101A: OASDG optical observations
- LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
- GRB 241228B: SAO RAS optical observations
- Konus-Wind detection of GRB 241228A
- GRB 241229B: Swift-BAT refined analysis
- Fermi GRB 241228B: Global MASTER-Net observations report
- GRB 241228A: Fermi GBM Observation
- GRB 241228B: TRT optical counterpart confirmation
- GRB 241228A: Swift detection of a burst
- Fermi trigger No 756678579: Global MASTER-Net observations report
- GRB 241217A/EP241217b: SOAR afterglow detection
- GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
- EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
- GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
- EP241217a: Liverpool Telescope optical follow-up
- EP241217a: Global MASTER-Net observations report
- GRB 241217A: GMG Optical Upper Limit
- GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
- GRB 241213B: Swift-XRT observations
- GRB 241213B: Tiled Swift observations
- GRB 241213B: CALET Gamma-Ray Burst Monitor detection
- GRB 241213B: MAXI/GSC detection
- EP241208a: Global MASTER-Net observations report
- Fermi GRB 241209E: Global MASTER-Net observations report
- Fermi GRB 241209A: Global MASTER-Net observations report
- GRB 241207C: MASTER optical observations
- GRB 241207C: Tiled Swift observations
- GRB 241207C: MAXI/GSC detection
- Fermi GRB 241206A: Global MASTER-Net observations report
- Fermi GRB 241204A: Global MASTER-Net observations report
- Fermi GRB 241201A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
- GRB 241127A: Swift-BAT refined analysis
- GRB 241026A: radio detection with the VLA
- GRB241120A: OHP/T193 optical observations
- GRB 241120A: Mondy and AbAO optical observations
- Fermi GRB 241118A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
- EP241113a: Global MASTER-Net observations report
- Fermi trigger No 753166198: Global MASTER-Net observations report
- Fermi-GBM Sub-Threshold Detection of GRB 241112B
- GRB 241112B: SVOM/GRM observation
- GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
- Fermi trigger No 752990530: Global MASTER-Net observations report
- Fermi trigger No 752878030: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
- EP241107a: AKO Optical Afterglow Follow-Up Observations
- GRB 240511A: LCO upper limits
- Fermi GRB 241105A: Global MASTER-Net observations report
- Fermi GRB 241104A: Global MASTER-Net observations report
- EP241101a: EP-FXT observations update
- Fermi trigger No 752365806: Global MASTER-Net observations report
- EP241103a: Swift XRT detection and improved X-ray position
- LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
- GRB 241101A: Swift detection of a burst
- Fermi trigger No 752083996: Global MASTER-Net observations report
- EP EP241030a: Global MASTER-Net observations report
- Fermi trigger No 752006065: Global MASTER-Net observations report
- GRB 241030B: Swift detection of a burst
- GRB 240912A: radio detection with the VLA
- Fermi GRB 241030A: Global MASTER-Net observations report
- GRB 241026A: SAO RAS observations of possible optical afterglow
- Fermi GRB 241026A: Global MASTER-Net observations report
- GRB 241026A: Prompt enhanced Swift-XRT position
- EP241021a: optical follow-up observations with Xinglong Observatory
- Fermi GRB 241025A: Global MASTER-Net observations report
- IPN triangulation of GRB 241021A (long)
- GRB241017A: 1.3m DFOT optical upper limit
- Fermi trigger No 750788395: Global MASTER-Net observations report
- GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
- Fermi GRB 241016A: Global MASTER-Net observations report
- GRB 240916A: radio detection with the VLA
- GRB241013A: REM observations
- Fermi trigger No 750211959: Global MASTER-Net observations report
- IceCube Alert 241006.94: Global MASTER-Net observations report
- EP EP240930a: Global MASTER-Net observations report
- Fermi GRB 240929A: Global MASTER-Net observations report
- LIGO/Virgo S240919bn: GOTO optical upper limits
- GRB 240918B: AstroSat CZTI detection
- EP240919a: EP-FXT follow-up observation update
- EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
- GRB 240918B: Fermi GBM Detection