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"19407 results found.
- GRB 061217: ROTSE-III Optical Limits
- GRB 061217: Swift detection of a short hard burst
- GRB 061210: MDM Follow-up Observation
- GRB061210: Swift/UVOT observations
- Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
- 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: 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: 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
- 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: 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: 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 061126: RAPTOR Optical Detection During Gamma-Ray Emission
- Swift XRT on-board boresight update
- GRB 061126: Early Super-LOTIS 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: 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
- GRB 061122: Candidate Optical Afterglow
- GRB 061121: Ep,i - Eiso correlation
- GRB061122: Swift/UVOT Optical Observations
- 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: Faulkes Telescope North Optical Observation
- GRB 061121: ROTSE-III Confirmation of Optical Counterpart
- GRB 061121: Swift detection of a bright burst with an optical counterpart
- GRB 060111B: Swift UVOT Refined Magnitudes
- Swift-BAT triggers 238544 and 238546 are not GRBs
- 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
- GRB061110B: Optical observations at Crni Vrh
- GRB 061110A: Swift XRT refined analysis
- GRB 061110B: Swift/XRT position
- 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: ROTSE-III Optical Limits
- GRB 061110: Swift detection of a burst
- Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
- 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 061028: Swift/XRT Astrometry Correction
- GRB 061102: Swift/UVOT Magnitude Upper Limits
- GRB 061102, XRT refined analysis
- 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: MDM Observations
- GRB 061028: SARA upper limit
- GRB061028: XRT refined analysis
- GRB 061028: Swift/UVOT Observations
- GRB 061028, Swift-BAT refined analysis
- GRB 061028: TAROT Calern observatory optical observations
- GRB 061028: Swift detection of a burst
- GRB 061027, Swift refined analysis of a possible burst