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.
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"- GRB 190129B: Tiled Swift observations
- Fermi GBM Observations of IceCube-190124A
- GRB 190129A: Fermi GBM detection
- Konus-Wind observation of extremely bright GRB 190129B
- IPN Triangulation of GRB 190129B (long/extremely bright)
- INTEGRAL observation of IceCube-190124A
- GRB 190129A: MAXI/GSC detection
- Trigger 886496: Another Swift trigger on MAXI J1348-630
- Swift Trigger 886157: MASTER optical observation
- Trigger 886486: Swift detection of MAXI J1631-479
- Trigger 886266: Another Swift trigger on MAXI J1348-630
- Swift Trigger 886157: Swift detection of a new transient Swift J1728.9-3613
- INTEGRAL triggers from 8205 to 8211 are due to MAXI J1348-630, NOT to a GRB
- GRB 190114C: Optical follow-up from HCT
- Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
- Trigger 885845: A second Swift trigger on MAXI J1348-630
- Trigger 885807: Swift detection of MAXI J1348-630
- Search for counterparts to IceCube-190124A with IceCube
- Search for counterpart to IceCube-190124A with ANTARES
- GRB 190117A: AstroSat CZTI detection
- GRB 190122B: AstroSat CZTI detection
- Fermi-LAT Gamma-ray Observations of IceCube-190124A
- GRB 190123A: IKI-GRB-FuN optical upper limit
- GRB 190123A: NEXT-0.6m optical limit
- GRB 190114C: CHILESCOPE optical observations
- GRB 190123A: AROMA-N Optical Observation
- IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
- GRB 190123A: Swift/UVOT Upper Limits
- Konus-Wind observation of GRB 190122A
- Konus-Wind of observation of GRB 190117A
- GRB 190123A: COATLI Optical Observations
- GRB 190123A: Swift-BAT refined analysis
- GRB 190121A: CALET Gamma-Ray Burst Monitor detection of a short burst
- GRB190123A: MITSuME Akeno optical upper limits
- GRB 190123A: GMG observational limit
- Trigger 885456: Swift detection of MAXI J1631-479
- GRB 190123A: Swift-XRT refined Analysis
- GRB 190123A: GOTO optical limit
- GRB 190123A: Fermi GBM observation
- GRB 190123A: BOOTES-4/MET optical limit
- GRB 190123A: Enhanced Swift-XRT position
- GRB 190123A: MASTER Global Robotic Net optical observation
- GRB 190123A: Swift detection of a burst
- GRB 190122A: Fermi GBM observation
- GRB 190122A: Fermi-LAT detection
- GRB 190114C: RTT150 optical observations
- IPN Triangulation of GRB 190118A (long)
- IPN Triangulation of GRB 190117A (long)
- Trigger 884906: Swift detection of MAXI J1631-479
- GRB 190114C: GMRT detection at 1.26GHz
- Swift ToO Instructions Update
- GRB 190114C: MeerKAT radio observation
- GRB 190117A: Insight-HXMT/HE detection
- Swift ToO Website Down
- GRB 190114C: UKIRT JHK observation (CORRECTIONS)
- GRB 190114C: UKIRT JHK observation continuation - steady fading?
- GRB 190114C: Sardinia Radio Telescope observations (CORRECTION)
- GRB 190114C: REM optical/NIR detection (CORRECTION)
- GRB 190114C: Sardinia Radio Telescope observations
- GRB 190117A: AGILE/MCAL detection of a burst
- GRB 190114C: RATIR Optical and NIR Detections
- GRB 190114C: RT-22 detection at 36.8 GHz
- GRB 190114C: COATLI Optical Detection
- GRB 190114C: ePESSTO NTT optical observations
- GRB 190114C: Continued UKIRT JHK observation
- GRB 190114C: continued CHILESCOPE optical obs
- GRB190114C: ATCA detection of the radio afterglow
- GRB 190106A: Discovery Channel Telescope observations
- GRB 190114B: continued optical observations in Mondy
- GRB 190114C: Optical detection from HCT
- GRB 190114C: CHILESCOPE optical observations
- GRB 190114C: UKIRT JHK observation
- GRB 190114A: NOEMA detection of the mm afterglow
- GRB 190114A:DOAO/LOAO optical observation
- Konus-Wind observation of GRB 190114C
- The Swift-XRT WT mode spectrum of GRB190114C
- GRB190114C, Long follow up urged
- GRB 190114C: KMTNet optical observation
- GRB190114C: GRowth-India detection of optical afterglow
- GRB 190114C: LSGT optical observation
- GRB 190114A: DOAO/LOAO optical observation
- GRB 190114B: Swift-XRT refined Analysis
- GRB 190114C: REM optical/NIR detection
- GRB 190114C: ALMA detection of a fading mm counterpart
- GRB 190114C: Mondy optical observations
- GRB 190114C: VLA Detection
- GRB 190114C: Swift/UVOT Detection
- GRB 190114C: Swift-BAT refined analysis
- GRB 190114B: Liverpool Telescope near-IR observations
- GRB 190114B: optical afterglow observations in Mondy and Abastumani observatories
- GRB 190114B, Swift-BAT refined analysis
- GRB 190114B: Swift/UVOT Upper Limits
- GRB 190114A: Swift/UVOT Observations
- GRB 190114A: Mondy optical afterglow detectio
- GRB 190114C: Optical observations
- GRB 190114C:Insight-HXMT/HE detection
- GRB 190114C: A type 1 BdHN with TeV emission
- GRB 190114C: SPI-ACS/INTEGRAL extended emission detection
- GRB 190114B: NOT optical counterpart
- GRB 190114C: AGILE/MCAL detection