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 100522A: NIR observations from CAHA
- GRB 100522A: BOOTES-2 optical limit
- GRB 100522A: Swift detection of a burst
- GRB 100418A: CrAO optical observations
- GRB 100518A: GROND afterglow observation and photo-z
- GRB 100518A: Swift/UVOT Upper Limits
- GRB 100518A: Swift-XRT refined analysis
- GRB 100518A: optical afterglow decay
- GRB 100518A: BOOTES-3 optical observations
- Update to the configuration of the Fermi-LAT onboard GRB search
- GRB 100518A: Faulkes Telescope North Afterglow Candidate
- GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
- GRB 100513A: MITSuME Akeno Optical Observation
- Swift-BAT trigger 422437 is not anything astrophysical
- GRB 100518A: a long GRB detected with INTEGRAL
- Swift Trigger 422437 is probably not a GRB
- Fermi/GBM trigger 295791986 - unreliable location
- GRB 100517A: MASTER-Net wide field camera prompt optical observations
- GRB 100513A: EVLA radio observation
- GRB 100514A: optical afterglow confirmation
- GRB 100514A: Swift/UVOT Observations
- GRB 100514A: YNAO-GMG observations
- GRB 100514A: Swift XRT refined analysis
- GRB 100514A: MASTER-Net optical observations
- GRB 100514A: Enhanced Swift-XRT position
- GRB 100514A: Swift-BAT refined analysis
- GRB 100514A: Faulkes Telescope South observations
- GRB 100514A: Swift detection of a burst
- GRB 100513A: Faulkes Telescope South observations
- GRB 100513A: Swift/UVOT upper limits
- GRB 100513A, RIMOTS optical upper limits
- GRB 100513A: Swift XRT refined analysis
- GRB 100513A: Swift-BAT refined analysis
- GRB 100513A: Gemini/GMOS Spectroscopic Redshift
- GRB 100513A: Enhanced Swift-XRT position
- GRB 100513A: Lick observations and R-band dropout
- GRB 100513A: PAIRITEL continued observations and confirmation of fading
- GRB 100513A: SARA-N Upper Limit
- GRB 100513A: PAIRITEL NIR afterglow candidate
- GRB 100513A: Swift detection of a burst
- GRB 100510A: Fermi GBM detection/observation
- GRB 100511A: Fermi GBM detection/observation
- GRB 100511A: Super-LOTIS early observations
- Swift-BAT trigger 421695 is likely not astrophysical
- GRB100504A: Optical upper limits at IAO
- GRB 100510A: MAXI/GSC detection
- GRB 100511A, RIMOTS optical upper limits
- Trigger 421695: Swift detection of a possible burst
- GRB100508A: Further Swift/UVOT Observations
- GRB100503A: Suzaku WAM observation of the prompt emission
- GRB 100508A: GROND Detection of the optical afterglow
- GRB 100508A: Swift-XRT Refined analysis
- GRB 100508A: Swift-BAT refined analysis
- GRB 100508A: Enhanced Swift-XRT position
- GRB100508A: Swift/UVOT Detection of the Afterglow
- GRB 100508A: ROTSE-III Optical Limits
- GRB 100508A: Swift detection of a burst
- GRB 100418A: Keck imaging
- GRB 100418A: RTT150 optical observations
- Fermi Gamma-ray Burst Monitor trigger 294712621 is not a GRB
- Swift-BAT refined analysis of trigger 421262
- GRB 100504A: Fermi GBM observation
- An SGR-like burst from the magnetar 1E 1841-04.5 in Kes 73
- GRB 100504A: Swift/UVOT Observations
- GRB 100418A: Flattening of the Swift/UVOT Optical Light Curve
- GRB 100504A: Swift-XRT refined analysis
- GRB 100504A: Enhanced Swift-XRT position
- GRB 100504A: GROND Upper limits
- GRB 100504A: Swift-BAT refined analysis
- GRB 100504A: SARA-South Upper Limit
- GRB 100503A: Fermi GBM detection
- GRB 100504A: UVOT-enhanced XRT position
- GRB 100504A: Swift detection of a burst
- Swift-BAT trigger 421072 is not astrophyical
- INTEGRAL observations of Swift GRB trigger 421072
- GRB100423A : Suzaku WAM observation of the prompt emission
- Trigger 421072: Possible Swift detection of a GRB or transient
- GRB 100420A: EVLA radio observations
- GRB 100420A: Gemini discovery of infrared afterglow
- GRB 100423A: xinglong TNT optical upper limit
- GRB 100420A: Terskol optical upper limit
- GRB 100427A: Swift XRT and UVOT Upper Limits
- GRB 100427A: Fermi GBM detection
- GRB 100424a. Radio observations
- GRB 100418A: RTT150 optical observations
- GRB 100427A detected in ground analysis of Swift BAT data
- GRB 100414A : EVLA Radio Detection
- GRB 100414A : WSRT Radio Detection
- Konus-Wind observation of GRB 100423A
- GRB 100423A: CrAO optical observations
- GRB 100418A: Terskol optical observations
- GRB 100424A: CrAO optical observations
- GRB 100424A: NIR Afterglow Confirmation
- GRB 100425A: Swift XRT refined analysis
- GRB 100424A: Gemini/NIRI H-band observations
- GRB100425A: Swift/UVOT Upper Limits
- GRB 100424A: Swift/UVOT Upper Limits
- GRB 100424A: Liverpool Telescope Upper Limits
- GRB 100425A: Enhanced Swift-XRT position
- GRB 100425A: Swift-BAT refined analysis