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"19042 results found.
- GRB 150727A: Continued RATIR Optical Observations - Fading
- GRB 150728A: AAO optical observations
- GRB 150728A: Swift/UVOT Upper Limits
- GRB 150728A: Swift-BAT refined analysis
- GRB 150728A: FTN observations
- GRB 150727A: RATIR Optical Observations
- GRB 150728A: Enhanced Swift-XRT position
- GRB 150728A: Swift detection of a GRB
- GRB 150727A: Swift-BAT refined analysis
- GRB 150727A: Watcher optical upper limit
- GRB 150727A: Swift/UVOT Detection
- GRB 150727A: Swift-XRT refined Analysis
- GRB 150727A: Enhanced Swift-XRT position
- GRB 150724B: Continued RATIR Optical Observations
- GRB 150727A: Swift detection of a burst with an optical counterpart
- GRB 150724B: Swift/UVOT Detection
- GRB 150724B: RATIR Optical Observations
- GRB 150724B: Swift ToO observations
- GRB 150724B: Fermi GBM detection
- Trigger 650221: Swift detection of a IGR J00291+5934
- GRB 150724A: Swift/UVOT Upper Limits
- GRB 150724A: Enhanced Swift-XRT position
- SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
- GRB 150724A: Swift detection of a burst
- GRB 150722A: Swift/UVOT Upper Limits
- GRB 150720A: Swift/UVOT Upper Limits
- GRB 150722A: Enhanced Swift-XRT position
- GRB 150722A: Swift-XRT observations
- GRB 150720A: Enhanced Swift-XRT position
- Swift Trigger 649706: a possible GRB or bright Galactic transient
- GRB 150711A: Burakan-ISON optical observations
- GRB 150716A: Swift/UVOT Upper Limits
- GRB 150716A: Continued RATIR Optical Observations
- GRB 150716A: P60 Candidate Optical Afterglow
- GRB 150716A: RATIR Optical Observations
- GRB 150716A: Swift detection of a burst
- Trigger 649113: Swift detection of SGR 1E 1841-045
- GRB 150710B: Swift-XRT afterglow detection
- GRB 150710B: Swift-XRT and Swift-UVOT observations
- GRB 150711A: Swift/UVOT Upper Limits
- GRB 150711A: Observations from the 2.5m NOT
- GRB 150711A: Enhanced Swift-XRT position
- GRB 150711A: Swift detection of a burst
- GRB 150710B: Swift ToO observations
- GRB 150710A: Swift/UVOT Upper Limits
- GRB 150710A: Swift-BAT refined analysis
- GRB 150710A: RATIR Observations
- Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
- Swift Trigger 648422: Swift-XRT observations
- IPN Triangulation of GRB 150702A
- GRB 150702A: Swift ToO observations
- GRB 150702A: Fermi-LAT detection
- GRB 150622A: Swift-XRT afterglow detection
- Swift Trigger 647642 is probably not an astrophysical source
- GRB 150627A: Swift/UVOT Detection
- GRB 150626B: Swift-XRT refined Analysis
- GRB 150627A: Swift ToO observations
- GRB 150626B: Swift/UVOT Upper Limits
- GRB 150626B: NOT optical upper limits
- GRB 150626B: Enhanced Swift-XRT position
- GRB 150626B: Swift detection of a burst
- GRB 150626A: Swift/UVOT Upper Limits
- GRB 150626A: Enhanced Swift-XRT position
- GRB 150626A: Swift detection of a burst
- V404 Cyg: MASTER Swift, Integral alert observations
- GRB 150622A: Tiled Swift observations
- GRB 150622A: MAXI/GSC detection
- Swift Trigger 645340: a possible GRB
- GRB 150616A: Watcher optical upper limit
- Swift triggers again on V404 Cyg
- Swift Trigger 644520 is V404 Cyg
- GRB 150616A: Swift/UVOT Upper Limits
- GRB 150616A: Swift-XRT refined Analysis
- GRB 150616A: Enhanced Swift-XRT position
- GRB 150616A: Swift detection of a burst
- V404 Cyg: Swift/UVOT Detection
- Optical follow-up of Swift trigger on V404 Cyg
- Swift trigger 643949 is V404 Cyg
- GRB 150615A: Swift-XRT refined Analysis
- GRB 150608A: Swift-XRT follow-up observations
- GRB 150615A: Swift/UVOT Detection
- GRB 150615A: Enhanced Swift-XRT position
- GRB 150615A: Swift detection of a burst
- GRB 150608A: MITSuME Akeno optical upper limits
- Trigger 643078: Swift detection of H1743-322
- Konus-Wind observation of GRB 150608A
- GRB150607A: AAO and CrAO optical observations
- GRB150607A: Discovery Channel Telescope Optical Observations
- GRB 150608A: Tiled Swift observations
- GRB 150608A: MAXI/GSC detection
- GRB 150607A: Swift-XRT refined Analysis
- GRB 150607A: Swift/UVOT Detection
- GRB 150607A: NOT optical observations
- GRB 150607A: Swift-BAT refined analysis
- GRB 150607A: Enhanced Swift-XRT position
- GRB 150607A: Swift detection of a burst with an optical counterpart
- GRB 150518A: possible SN observations
- Swift trigger 642453 is not an astrophysical source
- Swift Trigger 642453: a possible GRB
- GRB 150530B: Swift-XRT observations