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"- GRB 150413A: additional P60 observations
- GRB 150413A : Virtual Telescope optical observations
- GRB 150413A
- GRB 150413A: Bassano Bresciano Observatory optical observations
- Konus-Wind observation of a bright burst from SGR 1935+2154
- GRB 150413A: T7 and T18 optical observations
- GRB 150413A: Swift-BAT refined analysis
- GRB150413A, optical observations
- IPN Triangulation of a bright burst from SGR 1935+2154
- GRB 150413A: optical observations
- GRB 150413A: redshift determination with the 2.2m CAHA
- GRB 150413A: P60 photometry
- GRB 150413A: Khureltogot optical observations
- GRB 150413A: Tautenburg observations
- GRB 150413A: Nanshan optical and radio follow-ups
- GRB 150413A: Khureltogot optical observations
- GRB 150413A: MAXI/GSC detection
- GRB 150413A: MASTER very bright unusual OT observations
- GRB 150413A: MASTER bright OT detection
- GRB 150413A: Swift detection of a burst
- Swift trigger 637807 is probably not an astrophysical source
- Swift detection of SAX J1808.4-3658
- Swift GRB150402A: further XRT observations
- GRB 150407A: Swift-XRT observations
- GRB 150407A: optical observations
- GRB 150407A: Swift detection of a possible burst
- GRB 150407A: Swift ToO observations
- GRB 150403A: MASTER-net optical observation
- Swift triggered on a source in Terzan 5 (trigger=637212)
- GRB 150404A: Fermi GBM detection
- Konus-Wind observation of GRB 150403A
- Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
- GRB 150403A: Swift-BAT refined analysis
- GRB 150403A: Fermi GBM Detection
- GRB 150403A: Swift/UVOT Detection
- GRB 150403A: VLT/X-shooter redshift
- GRB 150323C: CrAO optical observations
- GRB 150323C: additional optical observations in Mondy
- GRB 150323C: Khureltogot optical observations
- GRB 150403A: Swift-XRT refined Analysis
- GRB 150403A: Fermi-LAT detection
- GRB 150403A: Enhanced Swift-XRT position
- GRB 150403A: Swift detection of a burst with an optical counterpart
- GRB 150402A: results of Swift observations
- GRB 150402A: RATIR Optical Observations
- GRB 150402A: Swift ToO observations
- GRB 150402A detected in ground analysis of Swift-BAT data
- Konus-Wind observation of GRB 150330A
- IPN Triangulation of GRB 150330A (long/very intense)
- GRB 150330A: Fermi GBM detection
- GRB 150323B: Swift-XRT afterglow detection
- GRB 141121A: GMG observation
- GRB 150323C: possible host galaxy detection
- GRB 141212A: GMG observation limit
- GRB 141220A: GMG observation limit
- GRB 141225A: GMG observation limit
- GRB 150120B: GMG observation
- GRB 150317A: likely host galaxy detection
- GRB 150323B: Khureltogot optical observations
- GRB 150323C: Nishi-Harima NIR Observations
- GRB 150323A: AAO optical observations
- GRB 150323C: MITSuME Akeno Optical observation
- GRB 150220A: Optical observations at Kyiv comet station
- GRB 150323C; Konkoly optical observations
- GRB 150323B; Konkoly optical observations
- GRB 150323A; Konkoly optical observations
- Konus-Wind observation of GRB 150323B
- Konus-Wind observation of GRB 150323A
- GRB 150323C: Mondy optical observations
- GRB 150323B : Xinglong TNT upper limit
- GRB 150323C, Swift-BAT refined analysis
- GRB 150323C: RATIR Optical Afterglow Observations - Errata
- GRB 150323C: Swift/UVOT Upper Limits
- GRB 150323B: Swift-XRT observations
- GRB 150323C: Enhanced Swift-XRT position
- GRB 150323C: RATIR Optical Afterglow Observations
- GRB 150323C : Xinglong TNT optical observation
- GRB 150323C: Swift-XRT refined Analysis
- GRB 150323C: Xingming upper limit
- GRB 150323A, Swift-BAT refined analysis
- GRB150323C: Fermi GBM detection
- GRB 150323A: KAIT Optical Observations
- GRB 150323C: Nanshan optical afterglow detection
- GRB 150323C: Prompt enhanced Swift-XRT position
- GRB 150323B: Fermi GBM observation
- GRB 150323C: MASTER-net optical observation
- GRB 150323C: Swift detection of a burst
- GRB 150323B: Swift ToO observations
- GRB 150323B detected in ground analysis of Swift-BAT data
- GRB 150323A: Swift-XRT refined Analysis
- GRB150323A: Swift-UVOT detection of the afterglow
- GRB 150323A: Keck redshift
- GRB 150323A: Enhanced Swift-XRT position
- GRB 150314A: GMG observation limit
- GRB 150323A: RATIR Optical Afterglow Observations
- GRB 150323A: P60 Optical Afterglow Candidate
- GRB 150323A: Swift detection of a burst
- Swift Triggers 635788-635794 are probably not real.
- Fermi GBM trigger 150319666 is not a GRB
- GRB 150318A: Swift-XRT refined Analysis