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.
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 090621B: MAGIC telescope GeV observation
- GRB 090621A: MAGIC telescope GeV observation
- GRB 090809: WHT observations
- GRB 090809 X-shooter redshift
- GRB 090809B: Fermi GBM detection
- GRB 090809: Swift-XRT refined analysis
- GRB090809: Swift/UVOT observations
- GRB 090809: Enhanced Swift-XRT position
- GRB 090809: Swift-BAT refined analysis
- GRB 090809: afterglow confirmation at the NOT
- GRB 090809: Swift detection of a burst with a possible optical counterpart
- GRB 090807: Liverpool Telescope observations
- GRB 090807: MITSuME optical upper limit
- GRB 090807: Swift/UVOT Upper Limits
- GRB 090807: Swift-XRT refined analysis
- GRB 090807, Swift-BAT refined analysis
- GRB 090807: Enhanced Swift-XRT position
- GRB 090807, RIMOTS optical upper limits
- GRB 090807: Swift detection of a burst
- Fermi Gamma-ray Burst Monitor trigger 271275771 is not a GRB
- GRB 090802B: Fermi GBM detection
- IPN Triangulation and Konus-Wind observaions of GRB090727B
- GRB 090802: Fermi GBM detection
- GRB 090726: optical observation
- Swift-BAT trigger 358760 is most likely not a GRB
- Swift trigger 358760 is probably a noise event
- GRB 090717A: Suzaku WAM observation of the prompt emission
- GRB 090709A : Quick look analysis of the Suzaku observation
- GRB 090728: Swift-BAT refined analysis
- GRB 090727: GRT Optical Observation
- GRB 090728: Swift XRT refined analysis
- GRB 090727: optical observations
- GRB 090726: GRT Optical Observation
- GRB 090727: Swift/UVOT Upper Limits
- GRB 090728: Swift/UVOT Upper Limits
- GRB 090728: Enhanced Swift-XRT position
- GRB 090727: I-band observations from 1.23m CAHA
- GRB 090728, RIMOTS optical upper limits
- GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
- GRB 090728: Swift detection of a burst
- GRB 090727: Swift-BAT refined analysis
- GRB 090727: Swift-XRT refined analysis
- GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
- GRB 090727: Enhanced Swift-XRT position
- GRB 090715B: Late-time Lick 3m observations
- GRB 090727: Liverpool Telescope possible OT candidate
- GRB 090727: Swift detection of a burst
- GRB090726: Swift/UVOT observations
- GRB 090726, Swift-BAT refined analysis
- GRB 090726: Afterglow candidate photometryfrom Crni Vrh
- GRB 090726: D50 optical observations
- GRB 090711: Fermi GBM detection
- GRB090726: 6-meter telescope redshift
- GRB 090726: Swift-XRT Team refined analysis
- GRB 090726: Enhanced Swift-XRT position
- GRB 090726: optical transient candidate
- GRB 090726: Swift/UVOT Finding Chart Observation
- GRB 090726: Swift-XRT position of probable counterpart
- GRB 090726: Swift detection of a burst
- Swift Trigger 358354 is not a GRB
- Konus-Wind and Konus-RF observations of GRB 090719
- Konus-RF and Konus-Wind observations of GRB 090718B
- Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
- Konus-Wind observations of bright hard GRB 090720B
- IPN Triangulation of bright GRB 090720B
- GRB 090720: Gemini-North Imaging and Optical Afterglow
- GRB 090720B: Fermi GBM detection
- Swift XRT and UVOT refned analysis of GRB 090720
- GRB 090709A: Swift XRT Timing Analysis
- GRB 090715B: VLA radio detection
- GRB 090720 Source found in ground processing of Swift-BAT data
- GRB 090717B: Fermi GBM detection
- GRB 090717: Fermi GBM detection
- GRB 090719: Fermi GBM detection
- GRB 090718B: Fermi GBM detection
- GRB 090718: Fermi GBM detection
- GRB 090720: Fermi GBM detection
- GRB 090715B: further NOT optical observations
- GRB 090715A: Suzaku WAM observation of the prompt emission
- GRB 090709A - CARMA mm Observations
- GRB 090715B: Lick observations
- GRB 090715A: VLA observations
- Konus-Wind observations of short/hard GRB 090715A
- GRB 090715B: MASTER optical limit
- GRB 090715A: Swift-BAT refined analysis
- Konus-Wind and Konus-RF observations of GRB 090715B
- GRB 090715B: Swift/UVOT followup observations
- GRB 090715B: break in the optical afterglow decay
- GRB 090715B: Enhanced Swift-XRT position
- GRB 090715B: Observation of the optical afterglow
- GRB 090715B: Swift XRT Refined Analysis
- GRB090715B: WHT redshift
- GRB 090715B: Swift-BAT refined analysis
- GRB 090715B: NOT optical observations
- GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
- Swift problem fixed
- GRB 090715B: Swift detection of a burst with a possible optical counterpart
- GRB 090715A: ROTSE-III Optical Limits
- GRB 090715: Swift detection of a short hard burst
- Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite