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"26042 results found.
- GRB 061210: MDM Follow-up Observation
- GRB061210: Swift/UVOT observations
- Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
- GRB 061210: Optical sources near XRT positions
- GRB 061210: Swift XRT analysis - Possible counterparts
- GRB 061210 : Faulkes North Telescope optical limit
- GRB 061214(?): ROTSE-III Optical Limits
- GRB 061214(?): Swift detection of a possible burst
- Swift/BAT trigger #250033 is due to a known source during loss of
- GRB 061213: MASTER-VWF-Kislovodsk optical candidate
- GRB 061213: MASTER-VWF-Kislovodsk observations
- GRB 061210: Gemini/GMOS Observations
- GRB 061126: Radio Observations
- GRB061201, VLT optical decay: correction
- GRB 061210: MDM Observation
- GRB 061210, Swift-BAT refined analysis of the SHB
- GRB 061210: Swift-BAT detection of a short burst
- Optical Afterglow observations of GRB 061126
- GRB061126: optical observations
- GRB 060926: MASTER: discovery of the optical flare
- GRB061126: update on the Swift-XRT afterglow light curve
- Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
- GRB 061201: UVOT Observations of a Fading Optical Afterglow
- GRB 061201: VLT optical decay
- GRB 061201: SOAR Confirmation of Candidate Afterglow
- GRB061126 : NMSU 1.0m observations
- GRB 061202: Swift XRT refined analysis
- GRB061202: FRAM early follow-up limit
- GRB061202 optical limit by "Pi of the Sky"
- Konus-Wind observation of GRB 061201
- GRB061202: optical/NIR observations with REM
- GRB061202: Swift/UVOT Upper Limits
- GRB 061202, Swift-BAT refined analysis
- GRB 061202: Swift detection of a burst
- GRB 061201: Swift XRT Team refined analysis
- GRB 061201: VLT optical observations
- GRB 061201: Initial UVOT Observations
- GRB 061201, Swift-BAT refined analysis of the SHB
- GRB 061201: Swift detection of a short hard burst
- GRB 061201: Coincidence with a Galaxy Cluster
- GRB 061122: GETS observation
- GRB 061121, SMARTS optical/IR observations
- GRB 061121: flattening of the decay
- INT+WFC observations of GRB 061126
- GRB 061126: Possible Jet Break
- GRB 061121: Second Epoch ATCA Radio Observations
- GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
- Swift XRT on-board boresight update
- GRB 061121: ATCA & WSRT Radio Observations
- GRB061121: optical observations
- GRB 061126: Early Super-LOTIS Observations
- GRB 061126: optical observation
- GRB 061126: Tautenburg afterglow observations
- GRB061126: Optical afterglow observations from MIRO
- GRB061126: Optical afterglow observations from MIRO
- GRB 061126: Swift-XRT refined analysis
- GRB 061126: Swift/UVOT Observations
- GRB 061126, Swift-BAT refined analysis
- GRB 061126: Early Detection of the IR Afterglow
- GRB 061126: Faulkes Telescope North Optical Observations
- GRB 061126: Swift/UVOT Afterglow Detection
- GRB 061126: XRT position
- GRB 061126: Swift detection of a burst
- GRB 061122: Confirmation of X-ray/Optical Afterglow
- GRB061121: optical observations
- GRB 061122: Candidate Optical Afterglow
- GRB 061121: Ep,i - Eiso correlation
- GRB 061121: MDM Optical Decay
- GRB061122: Swift/UVOT Optical Observations
- GRB 061121: ART detection in Ic
- GRB061121: P60 Observations
- Radio detection of GRB 061121
- GRB061122: Swift-XRT position
- GRB 061121 declared "Burst of Interest" by Swift team
- Konus-Wind and Konus-A observations of GRB 061121
- Swift-BAT trigger 239987 is not a GRB
- GRB 061121: Swift/UVOT Observations
- GRB 061121: Swift-XRT Team Refined Analysis
- GRB 061121, Swift-BAT refined analysis
- GRB061121, optical 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
- 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 061110B: Swift XRT refined analysis
- GRB 061110B, Swift-BAT refined analysis
- GRB 061110B: VLT redshift
- GRB061110B: Optical observations at Crni Vrh
- GRB 061110A: Swift XRT refined analysis