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 101024A: GRAS06 optical observations
- GRB 101024A: Enhanced Swift-XRT position
- Swift/UVOT observations of GRB101023A
- GRB 101024A: Swift detection of a burst with an optical afterglow
- GGRB 101023A: GROND detection of the optical-NIR afterglow
- GRB 101023A: Swift-XRT Team Refined Analysis
- GRB 101023A: Swift-BAT refined analysis
- GRB 101023A: Gemini discovery of optical afterglow
- GRB 101023A: Enhanced Swift-XRT position
- GRB 101023A: REM NIR observations
- GRB 101023A: Swift detection of a burst
- GRB 101011A: miniTAO/ANIR NIR upper limits
- GRB 101020A: MASTER prompt and afterglow limit
- GRB 101020A: BOOTES2 follow-up and limit
- GRB 101020A: MASTER polarization optical observations
- GRB 101020A, Swift-BAT refined analysis
- GRB 101020A: Swift detection of a burst
- GRB 101017A: miniTAO/ANIR NIR upper limits
- GRB 101017A: Swift XRT refined analysis
- GRB 101017A: Swift/UVOT Observations
- GRB 101008A: correction to the GCN 11352
- GRB 101008A: optical observations
- GRB101017A: MITSuME Okayama optical upper limits
- Konus-Wind observation of GRB 101017A
- GRB 101014A: Fermi LAT detection
- GRB 101017A: Enhanced Swift-XRT position
- GRB 101017A: Swift-BAT refined analysis
- GRB 101017A: ROTSE-III Optical Limits
- GRB 101017A: Swift detection of a burst with optical counterpart
- GRB 101011A: Fermi GBM detection
- GRB 101011A: BOOTES-3 Upper Limit
- Konus-Wind observation of GRB 101014A
- GRB 101014A: Fermi GBM detection
- GRB 100906A: D50 optical detection
- GRB 100902A: D50 optical limit
- GRB 101011A: Swift/UVOT observations
- GRB 101011A, GROND upper limits
- GRB 101011A: Zadko observatory - Gingin optical observations
- GRB 101011A: XRT Refined Analysis
- GRB 101011A: Swift/UVOT Observations of a Possible Optical Afterglow
- GRB 101011A: Enhanced Swift-XRT position
- GRB 101011A: Swift-BAT refined analysis
- GRB 101011A: Swift detection of a burst
- GRB 101008A: Fermi GBM observation
- GRB 101008A: MASTER prompt optical observations (correction to GCN#11328)
- GRB 101008A: MASTER prompt optical observations
- GRB 101008A: Swift-BAT refined analysis
- GRB101008A, GROND detection of a fading afterglow
- GRB 101008A: Swift-XRT refined analysis
- GRB 101008A: SAO RAS optical observations
- GRB 100915 optical upper limit
- GRB 101008: Swift/UVOT Upper Limits
- GRB 101008A: Enhanced Swift-XRT position
- GRB 101008A: 1.23m CAHA optical observations
- GRB 101008A: Swift/XRT Detection of an Afterglow with no UVOT Counterpart
- GRB 101008A: Swift detection of a burst
- GRB 100728B: X-shooter redshift
- Refined analysis shows Swift Trigger 435520 is not a GRB
- Swift Trigger 435520 is probably not a GRB
- GRB 100925A / MAXI J1659-152: MASTER optical observations
- GRB 100924A: Suzaku WAM observation of the prompt emission
- GRB 100928A, Swift-BAT refined analysis
- GRB 100924A: Fermi GBM observation
- GRB 100928A: Swift detection of a burst
- GRB 100925A / MAXI J1659-152: WSRT Radio and Polarization Detection
- GRB 100925A / MAXI J1659-152: Optical observation with the Kottamia 188cm telescope
- GRB100925A/MAXI J1659-152: X-shooter identification as an X-ray binary
- GRB100925A/MAXI J1659-152 MITSuME Ishigakijima and Okayama Optical Observation
- GRB 100925A / MAXI J1659-152: SARA-S Observations
- GRB 100925A/MAXI J1659-152: Submm observations from APEX
- GRB100925A/MAXI J1659-152: Galactic origin from SED analysis
- GRB 100925A/MAXI J1659-152 - NOT optical observations
- GRB 100925A / MAXI J1659-152: BOOTES-2/TELMA and IAC80 optical observations
- MAXI J1659-152: Swift-BAT refined analysis (triggers 434928 and 434931)
- GRB 100925A: Nearby DSS Source - SN-GRB or new Galactic transient?
- GRB100925A UVOT afterglow
- GRB 100924A: GROND detection of an optical/NIR afterglow
- GRB 100925A: Swift detection of a burst
- GRB 100924A: Swift-BAT refined analysis
- GRB 100924A: Swift detection of a burst
- GRB 100917A: TAROT La Silla observatory optical observations
- GRB 100915A: TAROT Calern observatory optical observations
- GRB100906A: Ashra-1 observation of early optical emission
- GRB 100916A: Fermi GBM detection
- GRB 100917A: Swift-BAT refined analysis
- GRB 100917A: Swift detection of a burst
- GRB100915A: MITSuME Ishigakijima Optical upper limits
- GRB 100915B: GRT Optical Observation
- GRB 100915A: GRT Optical Observation
- GRB 100915B: Fermi GBM observation
- GRB 100915A: Correction to Swift-BAT refined analysis
- GRB 100915A: Swift/UVOT Upper Limits
- GRB 100915A: Swift-BAT refined analysis
- GRB 100915A: Swift-XRT refined analysis
- GRB 100915A: Enhanced Swift-XRT position
- GRB 100915B: a long GRB detected by INTEGRAL
- GRB 100915A: Swift detection of a likely burst
- GRB 100910A: Fermi GBM detection
- Swift-BAT trigger 433953 is not a burst
- Swift BAT Trigger 433953 probably not a GRB