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.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"- RHESSI Spectrum of GRB061121
- Konus-Wind and Konus-A observations of GRB 061121
- INTEGRAL results on GRB 061122
- Swift-BAT trigger 239987 is not a GRB
- GRB 061122A: a long GRB detected by INTEGRAL
- GRB 061121: Swift/UVOT Observations
- GRB 061121: Swift-XRT Team Refined Analysis
- GRB 061121, Swift-BAT refined analysis
- GRB061121, optical observation
- GRB 061121 : Planned XMM-Newton observation
- GRB 061121: Optical observation at the KANATA 1.5m telescope
- GRB 061121: Faulkes Telescope North Optical Observation
- GRB061121: Spectroscopic Redshift
- GRB061121: Keck spectroscopic observations
- GRB 061121: ROTSE-III Confirmation of Optical Counterpart
- GRB 061121: Swift detection of a bright burst with an optical counterpart
- GRB 060605: NIR Observations
- GRB 050915B: optical afterglow
- GRB 060111B: Swift UVOT Refined Magnitudes
- Swift-BAT triggers 238544 and 238546 are not GRBs
- GRB061110A: Correction to GCN5817
- GRB 061110A: refined R-band analysis
- GRB 061110B: NIR Observations
- Swift TOO observations of GRB061110A
- Swift/UVOT Upper Limits for GRB061110b
- Swift/UVOT Upper Limits for GRB061110a
- GRB 061110A - VLT tentative redshift
- GRB 061110B: Swift XRT refined analysis
- GRB 061110B, Swift-BAT refined analysis
- GRB 061110B: VLT redshift
- GRB061110B: Optical observations at Crni Vrh
- GRB 061110B: NOT optical observations
- GRB 061110A: Swift XRT refined analysis
- GRB 061110B: Swift/XRT position
- GRB 061110B : Liverpool Telescope Optical Afterglow Detection
- GRB 061110B: Swift-UVOT Initial Observation
- GRB 061110A, Swift-BAT refined analysis
- GRB 061110B: TAROT Calern observatory optical observations
- GRB 061110B: Swift detection of a burst
- GRB 061110: NOT observations
- GRB 061110: Candidate confirmed
- GRB 061110 : Optical afterglow candidate
- GRB 061110: ROTSE-III Optical Limits
- GRB 061110: Swift detection of a burst
- GRB061110A - Optical Non-detection
- Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
- GRB 061109: optical observation
- GRB 061109: TAROT Calern observatory optical observations
- GRB 061109: Swift detection of a possible burst
- GRB061028: MAGIC telescope GeV observation
- GRB 061027: TAROT La Silla observatory optical observations
- GRB 061007: Third Epoch ATCA Radio Observations
- GRB061019: second epoch CrAO observations
- GRB 061028: Swift/XRT Astrometry Correction
- GRB 061102: Swift/UVOT Magnitude Upper Limits
- GRB 061102, XRT refined analysis
- GRB 061004: Further VLT/NTT observations
- Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
- GRB061102B: Super-LOTIS observations
- GRB 061028: Optical R passband observations
- GRB 061102B: Swift detection of a possible burst
- GRB 061102, Swift-BAT refined analysis
- GRB 061102: Swift detection of a burst
- GRB 061028: VLA Observation
- GRB 061004: Swift/XRT Astrometry Correction
- GRB 060801: Swift/XRT Astrometry Correction
- GRB 061028: Futher P200 Observations
- GRB 061028: MDM Observations
- GRB 061028: P200 Observations
- GRB 061028: SARA upper limit
- GRB 061028: z band imaging
- GRB061028: XRT refined analysis
- GRB 061028: Swift/UVOT Observations
- GRB 061028, Swift-BAT refined analysis
- GRB 061028: TAROT Calern observatory late optical observations
- GRB 061028: TAROT Calern observatory optical observations
- GRB 061028: Swift detection of a burst
- GRB 061027, Swift refined analysis of a possible burst
- GRB 061027: Swift detection of a possible burst
- GRB061025: ROTSE-III Confirmation of Optical Counterpart
- GRB061025: Swift XRT refined analysis
- GRB061025: Swift/UVOT observations
- GRB 061019: MITSuME upper limits
- GRB 061025: REM observations
- GRB 061025: Gemini-S observations
- GRB061025: Swift XRT position
- GRB 061025: ROTSE-III Optical Limits
- GRB 061025: a long GRB detected by INTEGRAL
- Swift XRT boresight update
- GRB 061021, Swift-BAT Lag analysis
- Konus-Wind observation of GRB 061021
- GRB 061021 - VLT spectrum without lines
- GRB 061021: Swift-XRT refined analysis
- GRB 061021: Swift/UVOT Observation
- GRB 061021, Swift-BAT refined analysis
- GRB 061021: Swift detection of a burst
- GRB 061019: Super-LOTIS upper limit
- GRB060904b: optical observations
- GRB061019: optical observations
- GRB061019: optical observations