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"20478 results found.
- GRB 090831A: Suzaku WAM observation of the prompt emission
- GRB 090904B: Swift/UVOT Refined Analysis
- GRB 090902B: Suzaku WAM observation of the prompt emission
- GRB 090829A: Suzaku WAM observation of the prompt emission
- GRB 090904A: Enhanced Swift XRT position
- GRB 090904B: Swift-BAT refined analysis
- GRB 090902B: VLA radio detection
- GRB 090904A: Swift-BAT refined analysis
- GRB 090904B: Enhanced Swift-XRT position
- GRB 090904A: Enhanced Swift-XRT position
- GRB 090904A: NOT observations
- GRB090904B: REM observations
- GRB 090904B: Swift detection of a burst
- GRB 090904A: ROTSE-III Optical Limits
- GRB 090904: Swift detection of a burst
- GRB 090902B: Swift/UVOT refined analysis
- GRB 090902B: GROND NIR Afterglow Observations
- GRB 090902B: Enhanced Swift-XRT position
- GRB090902B: Swift/UVOT observations
- GRB 090902B: Swift/XRT Afterglow Candidate
- GRB 090902B: Fermi LAT detection
- GRB 090831C: GROND upper limits
- Konus-Wind observations of GRB 090831A
- Swift Trigger 361477, called GRB090831B, is probably not real.
- GRB090831C: Swift/UVOT upper limits
- GRB 090831B: MITSuME optical upper limits
- GRB 090831C: Enhanced Swift-XRT position
- GRB 090831C: Swift detection of a burst
- GRB 090831B, RIMOTS optical upper limits
- GRB 090831B: Swift detection of a possible burst
- GRB 090827: Swift XRT and UVOT observations
- GRB 090828: Fermi GBM detection
- GRB 090817 - TLS Observations
- GRB 090823: Swift XRT possible detection of the X-ray afterglow
- GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
- GRB 090820: MASTER-Net optical polarization observations
- GRB 090820: Fermi GBM Detection of a bright burst.
- GRB 090817: optical upper limit
- GRB 090817: Confirmation of the X-ray afterglow
- GRB 090817: Swift/UVOT Upper Limits
- GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
- GRB 090817: Swift-XRT observations
- GRB 090814A: optical observations
- GRB 090813: Suzaku WAM observation of the prompt emission
- GRB 090812: Suzaku WAM observation of the prompt emission
- VLA radio non-detection of GRB 090812
- GRB 090813: CrAO optical obsevations
- GRB090814A: NOT optical follow-ups
- GRB 090814B: I-band observations from 1.23m CAHA telescope
- GRB 090814B: Swift/UVOT Upper Limits
- GRB 090814B: Swift-XRT detection of a possible afterglow.
- GRB 090814A: Swift/UVOT Observations
- GRB 090814A, RIMOTS optical upper limits
- GRB090814A: VLT spectroscopy
- GRB 090814: Enhanced Swift-XRT position
- GRB 090814: GROND Detection of an Optical Afterglow Candidate
- GRB 090814: Swift detection of a burst
- GRB090813: Swift/UVOT upper limits
- GRB 090813: Enhanced Swift-XRT position
- GRB 090813: P60 Optical Afterglow Confirmation
- GRB 090813: Swift detection of a burst
- GRB 090812: Faulkes Telescope South Continued Optical Monitoring
- GRB 090812: RAPTOR detections during the burst
- GRB 090812, RIMOTS optical upper limits
- GRB 090812 Swift-BAT Refined Analysis
- GRB090812: Swift/UVOT observations
- GRB 090812: GROND Observations of the Optical/NIR Afterglow
- GRB 090812: Enhanced Swift-XRT position
- GRB 090812: P60 Confirmation of Optical Afterglow
- GRB 090812: Swift detection of a burst with an optical counterpart
- GRB 090807B: Fermi GBM detection
- GRB 090809: Further NOT optical observations
- VLA radio upper limit on GRB 090809
- GRB 090809: WHT observations
- GRB 090809B: Fermi GBM detection
- GRB090809: Swift/UVOT observations
- GRB 090809: Enhanced Swift-XRT position
- GRB 090809: afterglow confirmation at the NOT
- GRB 090809: Swift detection of a burst with a possible optical counterpart
- GRB 090807: MITSuME optical upper limit
- GRB 090807: Swift/UVOT Upper Limits
- GRB 090807, Swift-BAT refined analysis
- GRB 090807: Enhanced Swift-XRT position
- GRB 090807, RIMOTS optical upper limits
- GRB 090807: Swift detection of a burst
- IPN Triangulation and Konus-Wind observaions of GRB090727B
- GRB 090726: optical observation
- Swift trigger 358760 is probably a noise event
- GRB 090717A: Suzaku WAM observation of the prompt emission
- GRB 090727: GRT Optical Observation
- GRB 090726: GRT Optical Observation
- GRB 090727: Swift/UVOT Upper Limits
- GRB 090728: Swift/UVOT Upper Limits
- GRB 090728: Enhanced Swift-XRT position
- GRB 090728, RIMOTS optical upper limits
- GRB 090728: Swift detection of a burst
- GRB 090727: Swift-BAT refined analysis
- GRB 090727: Enhanced Swift-XRT position
- GRB 090715B: Late-time Lick 3m observations
- GRB 090727: Swift detection of a burst