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"8482 results found.
- GRB 070406: Astrometrically Refined XRT Position, Unfading Source
- GRB 070406: Correction to the optical candidate in GCN6253
- GRB 070406: further analysis of NOT images.
- GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
- GRB 070406: NOT observations
- GRB 070406: Optical candidate
- GRB 070406: SARA upper limit
- GRB 070330, Swift-BAT refined analysis
- GRB 070330: Swift detection of a burst
- GRB 070328: Swift/UVOT Upper Limits
- long burst from SGR 1806-20 detected on March 26
- GRB 070328: Swift detection of a burst
- GRB070318: Swift-XRT refined analysis
- GRB 070318: Swift detection of a burst with an optical afterglow
- GRB 070309: variability of the XRT afterglow candidate
- GRB 070311: PAIRITEL confirmation of variability of REM candidate
- GRB 070311: REM candidate afterglow
- GRB060901: Candidate optical afterglow
- GRB 070125: Chandra X-ray Confirmation of Jet Break
- GRB070306: confirmation of near infrared afterglow
- GRB 070306: ART-3 early optical and near infrared constraints
- GRB 070306: IR observations and candidate afterglow
- GRB 070306: Swift detection of a burst
- GRB070227: Swift-XRT refined analysis
- GRB 070223: Optical Observations
- GRB 920925C: optical afterglow candidate
- GRB 070224: Optical afterglow confirmation
- GRB070224: Swift-XRT Astrometrically Corrected Position
- VLA observation of GRB 070223
- GRB 070224: WHT K-band imaging
- GRB 070224: optical afterglow candidate
- GRB 070224: MASTER-Net refind analysis
- GRB 070224: MASTER observations
- GRB 070224: Swift detection of a burst
- GRB 070223: Optical observations
- GRB 070223: Swift-XRT Refined Analysis
- GRB 070223: Liverpool Telescope Possible Afterglow Candidate
- GRB070223: Swift burst
- GRB 070220: MITSuME Okayama Optical Observation
- GRB 070220: Swift detection of a burst
- GRB 070219, Swift-BAT refined analysis
- GRB 070219: Swift detection of a burst
- GRB 070209: Swift detection of a short hard burst
- GRB 070208, Swift-BAT refined analysis
- GRB 070208: Afterglow confirmation from P60
- GRB070208: Faulkes Telescope North Afterglow Identification
- GRB 070208: Swift detection of a burst
- GRB070126: Swift-XRT Observation
- GRB 070125: WSRT Radio Detection
- GRB 070125: An IR Point Source and an Apparent Host Galaxy
- GRB 070129: Swift detection of a burst
- GRB 070125: MITSuME Okayama optical observation
- GRB 070125: PROMPT detections
- GRB 070125: WSRT Radio Observations
- Possible GRB 070126: Swift/UVOT Upper Limit
- GRB 070125: Continued P60 Observations
- GRB 070125: SARA detection in R
- GRB 070125: P60 Optical Afterglow Candidate
- GRB 070110: Continued Detection and Request for Ground Followup
- GRB 070110: UVOT Observations of a Candidate Afterglow
- 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, Swift-BAT refined analysis
- GRB 070107: Swift detection of a burst
- GRB070103: KPNO 4m+FLAMINGOS J limit
- GRB 070103: Swift detection of a burst
- Retractions of previous Swift-BAT triggers
- erratum : SDSS Pre-burst Observations of GRB061126
- GRB 061222A: Confirmation of Gemini Afterglow Candidate
- GRB 061222A: Xinglong Optical Limit
- GRB 061222A: Gemini Afterglow Candidate
- GRB061222A Swift/UVOT: Upper Limits
- GRB 061222B: Swift/UVOT Upper limits
- GRB061222B: Swift-XRT Refined Analysis
- GRB 061222B: SARA upper limit
- GRB 061222B: Swift detection of a burst
- GRB 061222: Swift detection of a burst
- GRB 061217: Astrometry-Corrected XRT Position
- GRB 061217: Confirmation of host candidate
- GRB 061217, Candidate host galaxy
- GRB061217: VLT NIR observations
- Swift triggers (#251863) on a possible burst
- GRB061217: Swift/UVOT refined analysis.
- GRB 061210: MDM Follow-up Observation
- GRB061210: Swift/UVOT observations
- GRB 061214(?): Swift detection of a possible burst
- GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
- GRB 061213: MASTER-VWF-Kislovodsk optical candidate
- GRB 061210, Swift-BAT refined analysis of the SHB
- GRB 061201: SOAR Confirmation of Candidate Afterglow
- GRB061202: Swift/UVOT Upper Limits
- GRB 061202: Swift detection of a burst
- GRB 061201: Swift detection of a short hard burst
- GRB 061121: Second Epoch ATCA Radio Observations
- GRB 061121: ATCA & WSRT Radio Observations
- GRB 061126: Swift/UVOT Afterglow Detection
- GRB 061122: Candidate Optical Afterglow
- GRB 061121: ROTSE-III Confirmation of Optical Counterpart
- GRB 061121: Swift detection of a bright burst with an optical counterpart