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 180914B: RTT150 optical observations
- GRB 180914B: RTT150 optical observations
- GRB 180930A: Swift-BAT refined analysis
- GRB 180930A: Swift-XRT refined Analysis
- GRB 180930A: NOT optical upper limits
- GRB 180930A: Swift/UVOT Upper Limits
- GRB 180930A: Enhanced Swift-XRT position
- GRB 180930A: KAIT Optical Upper Limit
- GRB 180930A: Prompt enhanced Swift-XRT position
- GRB 180930A: Swift detection of a burst
- INTEGRAL detections of the prompt gamma-ray emission of GRB 180914B
- GRB 180924A: Swift/UVOT Upper Limits
- GRB 180925A: VLT optical observations
- GRB 180925A: Insight-HXMT/HE detection
- GRB 180925A: Swift/UVOT Detection
- GRB 180925A: Swift-BAT refined analysis
- GRB 180925A: Swift-XRT refined Analysis
- GRB 180925A: Enhanced Swift-XRT position
- GRB 180925A: Prompt enhanced Swift-XRT position
- Konus-Wind observation of GRB 180923A
- GRB 180925A: Swift detection of a burst
- GRB 180924A: MASTER inspection
- GRB 180924A: Swift-XRT refined Analysis
- GRB 180923B - GBM Correction to GCN 23263
- GRB 180924A: Swift-BAT refined analysis
- GRB 180923B: Fermi GBM detection
- GRB 180924A: Enhanced Swift-XRT position
- GRB 180924A: Swift detection of a burst
- Swift Trigger 863053 is not an astrophysical event
- GRB 180923A: CALET Gamma-Ray Burst Monitor detection
- GRB 180923A: MASTER inspection MAXI/GSC error box
- GRB 180923A: MAXI/GSC detection
- GRB 180914B: OSN Detection and light curve/SED analysis
- GRB 180914B: OAJ multi-color follow-up
- Konus-Wind observation of GRB 180914A
- GRB 180914B: DDOTI/OAN Detection and Confirmation of Fading
- GRB 180914B: GOTO optical detection
- GRB180914B: Swift UVOT position correction to circ. 23241
- GRB 180914B: AstroSat CZTI detection
- GRB 180914B : continued TSHAO optical observations
- GRB 180914A: AstroSat CZTI detection
- IPN Triangulation of GRB 180914A (long)
- GRB 180914B: VLT/X-shooter spectroscopic redshift
- GRB 180914B: MASTER OT automatic dtection
- GRB 180914B : TSHAO optical observations
- GRB 180914B: Continued RATIR Optical and NIR Observations
- GRB 180914B: AGILE/MCAL refined analysis
- GRB180914B: Swift UVOT detection of an optical afterglow
- Konus-Wind of the very bright GRB 180914B
- GRB 180914B: Optical counterpart observation from OAJ
- GRB 180914B: RATIR Optical and NIR Observations
- GRB 180914B: KAIT Optical Afterglow Candidate
- GRB 180914B: Swift-XRT afterglow detection
- GRB 180914A: RATIR Optical and NIR Observations
- GRB 180914B: Tiled Swift observations
- GRB 180914B: Fermi-LAT detection
- GRB 180914B: AGILE/GRID detection
- GRB 180914A: MASTER automatic inspection
- GRB 180914A: Swift-XRT observations
- GRB 180914A: Tiled Swift observations
- GRB 180914A: Fermi GBM detection
- GRB 180914B: AGILE/MCAL detection of a burst
- GRB 180914A: Fermi-LAT detection
- IceCube-180908A: CALET Gamma-Ray Burst Monitor upper limits
- Fermi-LAT Gamma-ray Observations of IceCube-180908A
- INTEGRAL observation of IceCube-180908A
- Search for counterparts to IceCube-180908A with IceCube
- IceCube-180908A: HAWC follow-up
- Search for counterpart to IceCube-180908A with ANTARES
- GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
- GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
- GRB 180905A: Swift/UVOT Upper Limits
- IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
- GRB 180905A, Swift-BAT refined analysis
- GRB 180905A: RATIR Optical and NIR Observations
- GRB 180905A: MITSuME Akeno optical upper limits
- GRB 180905A: Swift-XRT refined Analysis
- GRB 180904A: BOOTES-2/TELMA early observations
- GRB 180905A: BOOTES-3/YA optical observations
- GRB 180905A: Enhanced Swift-XRT position
- GRB 180904A: AbAO optical upper limit
- GRB 180904A: Swift/UVOT Upper Limits
- GRB 180904A: RATIR Optical and NIR Observations
- GRB 180904A: Swift-BAT refined analysis
- Fermi GBM trigger 557852757/180905629 is not a GRB
- GRB 180905A: Swift detection of a burst
- GRB 180904A: Swift-XRT refined Analysis
- GRB 180904A: LT early observations
- GRB 180904A: SAO RAS optical observations
- GRB 180904A: OSN observations
- GRB 180904A: Enhanced Swift-XRT position
- GRB 180904A: NOT optical observations, candidate host galaxy
- GRB 180904A: Swift detection of a burst
- Konus-Wind observation of GRB 180828A
- GRB 180829A: Swift-XRT observations
- GRB 180828A: AstroSat CZTI detection
- GRB 180828A: Swift/UVOT Upper Limits
- GRB 180828A: RATIR Optical and NIR Observations
- GRB 180828A: Swift-BAT refined analysis
- GRB 180829A: Tiled Swift observations