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 130206A: Zadko observatory - Gingin optical observations
- Swift GRB 130206A - analysis of Swift/UVOT initial data.
- GRB 130206A: Swift-XRT observations
- GRB 130131A: optical observation in Mondy observatory
- GRB 130206A: Swift detection of a burst
- GRB 130131A: Swift/UVOT Upper Limits
- GRB 130131B: RATIR Upper Limits
- GRB 130131A: RATIR optical and infrared upper limits
- GRB 130131A: RAPTOR Limits During Gamma-Ray Emitting Interval
- GRB 130131B: Swift-XRT refined Analysis
- GRB 130131A - UKIRT confirmation of afterglow
- GRB 130131B: VLT/X-shooter acquisition camera limits
- GRB 130131B: GROND Upper limits
- GRB 130131A: CARMA 3mm Observations
- GRB 130131A: VLA 5.8 Ghz Detection
- GRB 130131B: IAC80 I-band observations
- GRB 130131B: Swift/UVOT Upper Limits
- GRB 130131A: Swift-XRT refined Analysis
- GRB 130131B: MITSuME Okayama optical upper limits
- GRB 130131A: MITSuME Okayama optical upper limits
- GRB 130131B: Enhanced Swift-XRT position
- GRB 130131B: Swift-BAT refined analysis
- GRB 130131A: Swift-BAT refined analysis
- GRB 130131B: TAROT Calern observatory optical observations
- GRB 130131B: Zadko observatory - Gingin optical observations
- GRB 130131A: Enhanced Swift-XRT position
- GRB 130131B: Swift detection of a burst
- GRB 130131A - Faulkes Telescope North Observations
- GRB 130131A - UKIRT afterglow candidate
- GRB 130131A: Swift detection of a burst
- Swift/BAT trigger 547142 is new source Swift J1753.7-2544
- GRB 130127A: Fermi GBM detection
- Swift Trigger 547142: MAXI/GSC upper limit
- GRB 130122A: RTT150 optical observations
- Swift Trigger 547142: a probable Galactic source
- GRB 130122A: CARMA 3mm Observations
- GRB 130122A: Swift/UVOT Detection
- GRB 130122A: optical observations
- GRB 130122A: RATIR Detection
- GRB 130122A: Swift-BAT refined analysis
- GRB 130122A: Swift-XRT refined Analysis
- GRB 130122A: Xinglong optical upper limit
- GRB 130122A: Enhanced Swift-XRT position
- GRB 130122A: MASTER-Net early marginal detection of the OT
- GRB 130122A: T100 observations
- GRB 130122A: Swift detection of a burst with an optical counterpart
- Short GRB 121226A: TNG observation of the host galaxy
- GRB 121225B: Suzaku WAM observation of the prompt emission
- GRB 130102B: MASTER synchronous observations
- GRB 130102A: Swift/UVOT Upper Limits
- Konus-Wind observation of GRB 130102B
- GRB 130102A: P60 Observations
- GRB 130102A: Swift-BAT refined analysis
- GRB 130102A: MASTER-Net optical observations
- GRB 130102A: Swift-XRT refined Analysis
- GRB 130102B: MAXI/GSC detection
- GRB 130102A: Enhanced Swift-XRT position
- GRB 130102A: IAC80 I-band observations
- GRB 130102A: Swift detection of a burst
- GRB 121226A: 5.8 GHz VLA observations
- Swift Trigger 544381 is a noise event
- GRB 121229A: Swift-XRT refined Analysis
- GRB 121229A, Swift-BAT refined analysis
- GRB 121229A: Swift/UVOT Upper Limits
- GRB 121229A: Enhanced Swift-XRT position
- GRB 121229A: VLT/X-shooter redshift
- Swift Trigger 544381 is unlikely to be a GRB
- GRB 121229A: MAXI/GSC detection
- GRB 121229A: GROND detection of the afterglow
- Skynet/PROMPT observations of GRB121229a
- GRB 121229A: Swift detection of a burst
- GRB 121226A: 10.4m GTC optical observations
- GRB 121226A: Swift/UVOT Upper Limits
- GRB 121226A: Swift-XRT refined Analysis
- GRB 121226A, Swift-BAT refined analysis
- GRB 121226A: NOT optical upper limit
- GRB 121226A: Optical Observations
- GRB 121226A: MITSuME Okayama Optical upper limits
- GRB 121226A: Zadko observatory - Gingin optical observations
- GRB 121226A: BOOTES-4/MET optical observations
- GRB 121226A: Swift detection of a burst
- Konus-Wind observation of GRB 121225B
- IPN Triangulation of GRB 121225B
- GRB 121225B: Fermi GBM observation
- GRB 121225B: Fermi LAT Detection
- GRB 121225A: MAXI/GSC detection
- Swift-BAT refined analysis of SGR 1E 1841-045 (Trigger=543763)
- Trigger 543763: SGR 1E 1841-045: Swift detection of a soft gamma repeater burst (aka Kes 73)
- GRB 121217A: ATCA 44GHz upper limit
- GRB 121217A: Swift-BAT refined analysis
- GRB 121217A theoretical estimate of redshift and of supernova occurrence
- GRB 121217A: Fermi GBM observation
- GRB 121217A: Swift-XRT refined Analysis
- GRB 121217A: Swift/UVOT Detection
- GRB 121217A: GROND Detection of the Afterglow
- GRB 121217A: Enhanced Swift-XRT position
- GRB 121217A: Swift detection of a burst
- GRB 121123A: NIKA (New IRAM KID Arrays) millimetre observations at the 30-m Pico Veleta telescope
- GRB 121209A: LOAO Observation
- GRB 121209A: Swift/UVOT Upper Limits