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"19357 results found.
- GRB 070110: Continued Detection and Request for Ground Followup
- GRB 070110: Ep,i - Eiso correlation
- GRB 070110 declared a "Burst of Interest" by Swift team
- Further Retractions of previous Swift-BAT triggers
- Swift-BAT Trigger 255685 is not a GRB
- Trigger 255685: Swift detection of a possible burst
- GRB 070110: UVOT Observations of a Candidate Afterglow
- GRB070110: Swift XRT Team refined analysis
- GRB 070110, Swift-BAT refined analysis
- GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
- GRB 070110: Swift detection of a burst with a possible optical afterglow
- GRB070107: Swift/XRT refined analysis
- GRB 070107: Possible UVOT Afterglow
- GRB 070107, Swift-BAT refined analysis
- GRB 070107: Swift/XRT position
- GRB 070107: Swift detection of a burst
- GRB070103: APO SPIcam i' and z' limits
- GRB 070103: Swift/UVOT Upper limits
- GRB070103: Swift XRT refined analysis
- GRB 070103, Swift-BAT refined analysis
- GRB 070103: TAROT Calern observatory optical observations
- GRB 070103: Swift detection of a burst
- Retractions of previous Swift-BAT triggers
- Konus-Wind observation of GRB 061222A
- GRB 061210: Swift/XRT Astrometry Correction
- GRB 050826: MDM Redshift
- GRB 061222B, Swift-BAT refined analysis
- GRB061222A Swift/UVOT: Upper Limits
- GRB 061222B: Swift/UVOT Upper limits
- GRB061222B: Swift-XRT Refined Analysis
- GRB 061222B: BOOTES-IR optical observations
- GRB 061222B: SARA upper limit
- GRB 061222A: Swift-XRT refined analysis
- GRB 061222A, Swift-BAT refined analysis
- GRB 061222B: TAROT La Silla observatory optical observations
- GRB 061222B: Swift detection of a burst
- GRB 061222A: Prompt ROTSE-III Optical Limits
- GRB 061222: Swift detection of a burst
- GRB 061217: Astrometry-Corrected XRT Position
- GRB 061217, Candidate host galaxy
- GRB 061217 - Swift/XRT position correction
- GRB 061218: TAROT La Silla observatory optical observations
- GRB 061217: TAROT Calern observatory optical observations
- GRB 061218, Swift-BAT refined analysis
- Swift triggers (#251863) on a possible burst
- GRB061217: Swift/UVOT refined analysis.
- GRB 061217: optical observations at Calar Alto
- GRB061217 - Swift/XRT refined analysis
- GRB 061217, Further Swift-BAT refined analysis of the short hard burst
- GRB 061217, Swift-BAT refined analysis
- 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