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.
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"12332 results found.
- GRB 090823: Swift XRT possible detection of the X-ray afterglow
- GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
- GRB 090817: aphotometry of USNO-B1.0 341-0096763
- GRB 090817: Liverpool Telescope Observations
- GRB 090817: optical upper limit
- GRB 090815C: Swift refined analysis
- GRB 090817: Swift/UVOT Upper Limits
- GRB 090817: Swift-XRT observations
- GRB 090814B: I-band observations from 1.23m CAHA telescope
- GRB 090814B: Swift/UVOT Upper Limits
- GRB 090814B: Liverpool Telescope Observations
- GRB 090814A: Swift/UVOT Observations
- GRB 090814A, RIMOTS optical upper limits
- GRB 090813: correction to GCN 9787
- GRB090813: Swift/UVOT upper limits
- GRB 090813: Swift detection of a burst
- GRB 090812: WIRO NIR upper limit
- GRB 090812, RIMOTS optical upper limits
- GRB090812: Swift/UVOT observations
- GRB 090812: GROND Observations of the Optical/NIR Afterglow
- VLA radio upper limit on GRB 090809
- GRB 090621B: MAGIC telescope GeV observation
- GRB 090621A: MAGIC telescope GeV observation
- GRB090809: Swift/UVOT observations
- GRB 090807: MITSuME optical upper limit
- GRB 090807: Swift/UVOT Upper Limits
- GRB 090807, RIMOTS optical upper limits
- GRB 090807: Swift detection of a burst
- GRB 090727: GRT Optical Observation
- GRB 090726: GRT Optical Observation
- GRB 090727: Swift/UVOT Upper Limits
- GRB 090728: Swift/UVOT Upper Limits
- GRB 090728, RIMOTS optical upper limits
- GRB 090728: Swift detection of a burst
- GRB090726: Swift/UVOT observations
- Swift XRT and UVOT refned analysis of GRB 090720
- GRB 090715B: Swift/UVOT followup observations
- GRB 090709A: Xinglong TNT optical upper limit
- GRB 090621B: MTM-500 optical observations
- GRB 090709A: Swift UVOT upper limits
- GRB 090709A: evidence for a very red afterglow at low z
- GRB 090709A: P60 Observations
- GRB 090709A: Wyoming Infrared Observatory NIR upper limits
- GRB 090709A, RIMOTS optical upper limits
- GRB 090709: Faulkes Telescope North Upper Limits
- GRB 090709: PAIRITEL NIR Upper Limits
- Possible GRB090705: Swift-XRT observations
- GRB 090705: Swift detection of a possible burst
- XRF 090702 : RTT150 optical observations
- GRB 090529: CrAO optical upper limit
- GRB 090529: MTM-500 optical observations
- GRB 090702: UVOT upper limits
- GRB 090628: Swift/UVOT Upper Limits
- GRB 090628: GROND upper limits
- GRB 090628: Swift/UVOT Finding Chart Observation
- GRB 090625B: Swift/UVOT Upper Limits
- GRB 090625B: GROND upper limits
- GRB 090621B: GRT Optical Observation
- GRB 090621A: GRT Optical Observation
- GRB 090621B: Swift/UVOT Upper Limits
- GRB 090621: Swift/UVOT Upper Limits
- GRB 090621: Swift detection of a burst
- GRB090618: Swift/UVOT bright afterglow detection
- GRB 090618: AGILE observations
- GRB 090607: Swift/UVOT Upper Limits
- GRB 090607: GRAS001 optical observations
- GRB 090530: Further NOT optical observations
- GRB 090530: RTT150 Optical Observation
- GMRT observation of GRB 090424 afterglow
- GRB 090531B: GROND observation
- GRB090529B: ROVOR Upper Limits
- GRB 090531A: SARA upper limit
- Corrections to GRB 090531B Swift/UVOT Upper Limits
- GRB 090531B, RIMOTS optical upper limits
- GRB 090531B: Swift/UVOT Upper Limits
- GRB 090530: GRT Optical Observation
- Initial Swift/UVOT observations of GRB 090531B
- GRB 090531: GROND upper limits
- GRB090530: Swift XRT refined analysis
- GRB090530: Swift/UVOT afterglow detection
- GRB 090530: GRAS002 refined OA analysis
- GRB 090530: GRAS002 optical observations
- GRB090529: UVOT/Swift detection of a brightening optical afterglow
- GRB 090529: Preliminary Swift/UVOT Upper Limit
- GRB 090529: Swift detection of a burst
- GRB 090518 - NOT upper limit
- GRB 090520: GROND upper limits
- GRB 090519: Swift/UVOT Upper Limits
- GRB 090519: Swift detection of a burst
- GRB 090518: Swift/UVOT Upper Limits
- GRB090518: GROND upper limits
- GRB 090516, RIMOTS optical upper limits
- GRB090518 : Optical upper limit by MOA-II telescope
- GRB 090516: Swift/UVOT Observations
- GRB 090516: Swift detection of a burst
- GRB 090515: Lick Upper Limits
- GRB 090515: ROVOR Upper Limit
- GRB 090515: MMT/MMIRS NIR Upper Limit
- GRB 090515: Swift/UVOT Observations
- GRB 090515: Swift-XRT refined analysis