GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"- Swift Trigger 554135 is probably not a GRB or transient
- GRB 130420B: RATIR Optical and NIR Observations
- GRB 130420A: Continued RATIR Optical and NIR Observations
- GRB 130420B: Swift-XRT refined Analysis
- GRB 130420A: Fermi GBM observation
- GRB 130420A: ISON-NM optical observations
- Skynet/GORT observations of GRB130420A
- GRB 130420B: Weihai optical upper limit
- GRB 130420B: Swift/UVOT Upper Limits
- GRB 130420A: Swift/UVOT Detection
- GRB130420B: GMG optical upper limit
- GRB 130420A: Swift-XRT refined Analysis
- GRB 130420B: Enhanced Swift-XRT position
- GRB 130420B, Swift-BAT refined analysis
- GRB 130420A, Swift-BAT refined analysis
- GRB 130420A: GMG optical observation
- Konus-Wind observation of GRB 130418A
- GRB 130420A: Enhanced Swift-XRT position
- GRB130420A : Xinglong TNT optical upper limit
- GRB 130420B: Faulkes Telescope North observations
- GRB 130420A: Weihai Optical Observations
- GRB 130420B: MASTER-Net optical observations
- GRB 130420B: Swift detection of a burst
- GRB 130420A: T21 optical observations
- GRB 130420A: RATIR Optical and NIR Observations
- GRB 130420A: PAIRITEL NIR detections
- GRB 130420A: ROTSE-III Detection of Optical Counterpart
- GRB 130420A: Swift detection of a burst with an optical counterpart
- GRB 130420A: Faulkes Telescope North candidate
- GRB 130418A: Continued RATIR Optical and NIR Observations
- GRB 130418A: Swift-XRT refined Analysis
- Swift Trigger 553930 is not an astrophysical source
- GRB 130418A: SMARTS optical/IR afterglow observations
- GRB 130418A: Submm observations from SMA
- GRB 130419A, Swift-BAT refined analysis
- GRB 130327B: Swift/XRT source is not the afterglow
- GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
- Trigger 553930: Swift detection of a possible flare from HR 5110
- GRB 130418A: T21 optical observation
- GRB 130418A: T18 and T21 optical observations
- GRB 130418A: LOAO Observation
- GRB 130418A, Swift-BAT refined analysis
- GRB 130419A: Swift detection of a burst
- GRB130418A: VLT/X-shooter redshift confirmation
- GRB 130418A: REM NIR observations
- GRB 130418A: RATIR Optical and NIR Observations
- GRB 130418A: CARMA 3mm detection
- GRB 130418A: GROND detection of the optical-NIR afterglow
- GRB130418A: OSN 1.5m fading afterglow detection
- GRB 130418A: Swift/UVOT Detection and request for continuing coverage
- GRB 130418A: Enhanced Swift-XRT position
- GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
- GRB 130418A: TNG optical observations
- GRB 130418A: Redshift from 10.4m GTC
- GRB 130418A: Bassano Bresciano Observatory optical observations
- GRB 130418A: 1.23m I-band observations
- GRB 130418A: Swift detection of a burst with an optical counterpart
- GRB 130408A: Suzaku WAM observation of the prompt emission
- GRB 130408a: Skynet Optical Observations
- GRB 130408A: SMARTS optical/IR afterglow observations
- GRB 130408A, Swift-BAT refined analysis
- GRB 130408A: Zadko observatory - Gingin optical observations
- GRB 130407A: Swift-XRT observations
- GRB130408A: Swift/UVOT followup observations
- GRB 130408A: Swift-XRT refined Analysis
- Konus-Wind observation of GRB 130408A
- GRB 130408A: Enhanced Swift-XRT position
- GRB 130408A - Gemini-S/GMOS redshift determination
- GRB 130408A - VLT/X-shooter redshift determination
- GRB 130408A: GROND detection of the afterglow
- GRB 130408A: Swift/UVOT Detection of the Optical Afterglow
- GRB 130408A: Liverpool Telescope Optical candidate detection
- GRB 130408A: Swift detection of a burst
- GRB 130407A Tiled Swift observations
- GRB 130407A: MAXI/GSC detection
- GRB 130211A: Retraction of afterglow candidate
- GRB 130327B: Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 130320B
- Swift detection of IGR J18245-2452
- IPN Triangulation of GRB 130320B (very long/bright)
- Swift/XRT observation of GRB 130327B
- GRB 130327A: RATIR Optical/NIR afterglow confirmation
- GRB 130306A: Confirmation of the X-ray Afterglow
- GRB 130310A: RATIR Observations
- Swift Trigger 552142 is a noise event
- Konus-Wind observation of GRB 130327B
- GRB 130327B: Fermi-LAT detection of a burst
- GRB 130327B: Fermi GBM detection
- Swift Trigger 552142: a possible GRB
- GRB 130327B: gamma-ray detection by AGILE
- GRB 130327A: Swift-BAT refined analysis
- GRB 130327A: Gemini Observations
- GRB 130327A: Swift-XRT refined Analysis
- GRB 130327A: Weihai optical obsevations
- GRB 130327A: Swift/UVOT Upper Limits
- Konus-Wind observation of GRB 130325A
- GRB 130327A: ISON-NM optical upper limit
- GRB 130325A Tiled Swift observations
- GRB 130327A: Enhanced Swift-XRT position
- GRB 130327A: RATIR Optical and NIR Observations