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"5046 results found.
- GRB 100814A: Swift detection of a burst with an optical afterglow
- GRB 100814A: ROTSE-III Detection of Optical Counterpart
- Swift-BAT trigger 431582 likely is IGR J17464-2811
- GRB100807A: optical observation in CrAO
- GRB 100807A: P60 Optical Afterglow Discovery
- GRB 100719A: Swift detection of a burst
- GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
- GRB 100628A: Chandra observations
- GRB 100628A: Swift XRT/UVOT refined analysis
- Konus-Wind observation of GRB 100704A
- GRB 100704A: Fermi GBM observation
- GRB 100704A: Swift detection of a burst
- GRB 100615A: Additional Gemini/NIRI observations
- GRB 100701B: Fermi GBM detection
- GRB 100702A: Swift detection of a short burst
- GRB 100213B: Detection of Fading Optical Afterglow
- GRB 100628A: Gemini North Observations
- GRB 100628A: Swift XRT refined position
- GRB 100628A: Magellan near-IR observations
- GRB 100628A: Swift XRT detection of a possible X-ray afterglow
- GRB 100625A : IRSF/SIRIUS NIR upper limit
- GRB 100625A: Gemini candidate afterglow
- Konus-Wind observation of GRB 100621A
- GRB 100619A: Correction to the Fermi GBM trigger time
- GRB 100621A: GROND observation of bright NIR afterglow
- GRB 100621A: ROTSE-III Optical Limits
- GRB 100621A: Swift detection of a burst
- GRB 100619A: Fermi GBM detection
- XRF 100616a : MAXI/GSC detection of a probable XRF
- GRB 100615A: Swift detection of a burst
- GRB 100513A: CrAO optical observations
- Konus-Wind observation of GRB 100522A
- GRB100522A: Suzaku WAM observation of the prompt emission
- GRB 100522A: Fermi GBM observation
- GRB 100522A: Swift detection of a burst
- GRB 100513A: PAIRITEL NIR afterglow candidate
- GRB100503A: Suzaku WAM observation of the prompt emission
- GRB 100503A: Fermi GBM detection
- GRB 100424A: PAIRITEL NIR Upper Limits
- Swift Trigger 420256: BOOTES-2 observations
- Swift Trigger 420256: ROTSE-III Optical Limits
- GRB100420A: MITSuME optical upper limits
- GRB 100414A: GROND Detection of the Optical Afterglow
- GRB 100413: xinglong TNT optical upper limit
- INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
- Short X-ray Transient detected by MAXI/GSC
- GRB 100322A: Suzaku WAM observation of the prompt emission
- XRF 100315A: MAXI/GSC detection of a short X-ray transient
- GRB100305A: Optical upper limits at IAO
- GRB 100305A: PAIRITEL NIR Upper Limits
- GRB 100302A: Ondrejov 65cm limit
- GRB 100302A: Optical observations at Crni Vrh
- GRB 100206A: optical observations in Terskol
- GRB 100216A: Swift/UVOT Observations
- GRB 100206A: WHT candidate afterglow
- GRB 100206A: Pre-explosion imaging and host candidate
- GRB 100203A Detected in Ground Analysis of BAT Data
- Swift/BAT Detects an Outburst from XTE J1901+014
- GRB 091221: Enhanced Swift-XRT position
- GRB 091221: UVOT Confirmation of an Optical Afterglow
- GRB 091221: ROTSE-III Detection of Optical Counterpart
- GRB 091208B: MITSuME Okayama Optical Observation
- GRB 091202: Optical and NIR observations
- GRB 091127: redshift confirmation with X-shooter
- Short X-ray Transient Detection by MAXI/GSC
- GRB 091126B: Fermi GBM detection
- GRB 091130: MASTER observations
- GRB 091127: NOT observations
- GRB 091117: Swift XRT refined analysis
- GRB 091117: XRT source coincident with a DSS galaxy
- GRB 091109B: VLT observations
- GRB 091109B: Swift detection of a short burst
- GRB 091109: BOOTES-3 observations
- GRB 091029: GROND Detection of the Optical/NIR Afterglow
- GRB 091029: Swift detection of a burst with an optical counterpart
- GRB 091003A: Fermi LAT detection
- GRB 091003A: Fermi GBM detection
- GRB 090927: Swift XRT refined analysis
- GRB 090926B: optical object in error circle
- GRB 090926B: MAXI GSC detection
- GRB 090926B: Swift XRT refined analysis
- GRB 090915: Swift-XRT detection of a fading X-ray counterpart
- GRB 090912: Swift detection of a burst
- GRB 090902B: Faulkes Telescope North observations
- GRB 090831B: MITSuME optical upper limits
- GRB 090831B, RIMOTS optical upper limits
- GRB 090831B: Swift detection of a possible burst
- Fermi Gamma-ray Burst Monitor trigger 273123112 is not a GRB
- GRB 090814B: Liverpool Telescope Observations
- GRB 090814A, RIMOTS optical upper limits
- GRB 090813: Liverpool Telescope afterglow confirmation
- GRB 090813: P60 Optical Afterglow Confirmation
- GRB 090812: Liverpool Telescope afterglow confirmation
- GRB 090812: Swift detection of a burst with an optical counterpart
- GRB 090809 X-shooter redshift
- GRB 090807: MITSuME optical upper limit
- GRB 090807: Swift detection of a burst
- GRB 090726: GRT Optical Observation
- GRB 090727: I-band observations from 1.23m CAHA
- GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare