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 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: RATIR Optical Observations
- GRB 150402A: Swift ToO observations
- IPN Triangulation of GRB 150330A (long/very intense)
- 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
- GRB 150323C: Mondy optical observations
- GRB 150323C: Swift/UVOT Upper Limits
- GRB 150323C: Enhanced Swift-XRT position
- GRB 150323C: RATIR Optical Afterglow Observations
- GRB 150323C: Swift-XRT refined Analysis
- GRB 150323C: Xingming upper limit
- GRB150323C: Fermi GBM detection
- GRB 150323C: Nanshan optical afterglow detection
- GRB 150323C: Swift detection of a burst
- GRB 150323B: Swift ToO observations
- GRB 150323A: Swift-XRT refined Analysis
- GRB150323A: Swift-UVOT detection of the afterglow
- 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
- GRB 150318A: Skynet PROMPT-CTIO Observations
- GRB 150318A: Swift/UVOT Upper Limits
- GRB 150318A : GROND upper limits
- Swift Trigger 635306 is probably not an astrophysical source
- GRB 150318A: Enhanced Swift-XRT position
- GRB 150318A: Swift detection of a burst
- GRB 150317A: Swift/UVOT Upper Limits
- GRB 150317A: Swift-XRT refined Analysis
- GRB 150317A: RATIR Optical Afterglow Detection
- GRB 150317A: Enhanced Swift-XRT position
- GRB 150317A: NOT optical observations
- GRB 150317A: Swift detection of a burst
- GRB 150314A: Early RAPTOR Detection
- GRB 150314A: NOT further optical observations
- GRB 150314A: NOT optical observations
- GRB 150314A: Swift/UVOT Detection
- GRB 150314A: Skynet Yerkes-41 Observations of the Optical Afterglow
- GRB 150314A: Enhanced Swift-XRT position
- GRB 150314A: Swift detection of a bright burst
- GRB 150309A: AAO optic upper limit
- GRB 150222A: CrAO optical observation
- GRB 150309A: CrAO optic upper limit
- GRB 150309A: ISON-Kislovodsk optic upper limit
- GRB 150309A: Swift-BAT refined analysis
- GRB150309A: Optical observations at Crni Vrh
- GRB 150309A: Swift/UVOT Upper Limits
- GRB 150309A: Swift-XRT refined Analysis
- GRB 150309A: Enhanced Swift-XRT position
- GRB 150309A: Swift detection of a burst
- Chandra X-ray observations of SWIFT J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka p[PFH2005] 622)
- Further UVOT Observations of Swift J0045.2+4151
- Further X-ray observations of Swift J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka [PFH2005] 622)
- BAT trigger 633105 (GRB 150301C): NOT r-band upper limit
- GRB 150302A: BOOTES-2/TELMA upper limit
- Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
- GRB 150302A: Mondy optical upper limit
- GRB 150302A: Swift/UVOT Upper Limits
- GRB 150302A: MITSuME Okayama upper limits
- GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
- GRB 150302A: Enhanced Swift-XRT position
- GRB 150220A: further Swift-XRT observations
- GRB 150301B: Swift/UVOT Observations
- GRB 150302A: UVOT Observations
- GRB 150302A: NOT afterglow candidate
- GRB 150302A: Swift detection of a burst
- GRB 150301B: GROND afterglow observations
- GRB 150301A: Swift/UVOT Upper Limits
- GRB 150301B: Enhanced Swift-XRT position
- GRB 150301A: Swift-BAT refined analysis
- GRB 150301C : (Swift trigger 633105) Swift observations
- GRB 150301B: Swift detection of a burst with an optical afterglow
- Swift Trigger 633173 is probably not an astrophysical source
- GRB 150301A: GROND Observations
- Trigger 633105 is likely not a GRB
- GRB 150301A: Swift detection of a short burst or new SGR
- Fermi GBM Observations of Magnetar 4U 0142+61
- Trigger 632888: Swift detection of the magnetar 4U 0142+61
- GRB 150222A: Further GROND Observations
- GRB 150220A: Swift ToO observations