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"21451 results found.
- GRB 061210: Swift/XRT Astrometry Correction
- GRB 050826: MDM Redshift
- GRB 061222A: MITSuME Akeno optical upper limits
- GRB 061222A: Gemini Afterglow Candidate
- GRB 061222B, Swift-BAT refined analysis
- GRB061222A Swift/UVOT: Upper Limits
- GRB 061222B: Swift/UVOT Upper limits
- GRB061222B: Swift-XRT Refined Analysis
- GRB 061222A: Observation with the KANATA 1.5m telescope
- 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 061222b: optical afterglow
- GRB 061222A: Prompt ROTSE-III Optical Limits
- GRB 061222: Swift detection of a burst
- GRB 061217: Astrometry-Corrected XRT Position
- GRB 061217: Confirmation of host candidate
- GRB 061217: Object ib GCN 5948 is a star
- GRB 061217: Extended object in the revised XRT error circle
- GRB 061217, Candidate host galaxy
- GRB 061217 - Swift/XRT position correction
- GRB 061210: Possible Host Galaxy (S2-G2) Keck Spectrum
- GRB 061218: TAROT La Silla observatory optical observations
- GRB 061217: TAROT Calern observatory optical observations
- GRB 061218, Swift-BAT refined analysis
- GRB061217: VLT NIR observations
- 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: 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: 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
- 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
- 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 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 050915B: optical afterglow
- GRB 060111B: Swift UVOT Refined Magnitudes