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"- GRB 121027A: Swift/UVOT Possible Detection
- GRB 121024A: LOAO RIzY Observation
- GRB 121027A: X-shooter redshift confirmation
- GRB 121027A - Gemini South spectroscopy
- GRB 121024A: SMARTS optical/IR afterglow observations
- GRB 121028A: near-IR observations at Calar Alto
- GRB 121027A: GROND Confirmation of Rebrightening
- GRB 121029A: Fermi GBM detection
- GRB 121028A: RAPTOR Limits During Gamma-Ray Emitting Interval
- Swift Quick-look and HEASARC will be offline for due to hurricane Sandy
- GRB 121027A: MASTER early prompt optical limit
- GRB 121027A: Swift-XRT refined Analysis
- GRB 121027A: Brightening IR counterpart
- GRB 121028A: Swift-XRT refined Analysis
- GRB 121028A: Enhanced Swift-XRT position
- GRB 121028A: Swift-BAT refined analysis
- GRB 121027A: Enhanced Swift-XRT position
- GRB 121028A: MITSuME Okayama Optical upper limits
- GRB 121028A: Faulkes Telescope North observations
- GRB 121028A: Swift detection of a burst
- GRB 121011A: optical observations
- GRB 121027A: nIR afterglow candidate with AAT
- GRB 121027A: Swift-BAT refined analysis
- GRB 121025A: Swift-XRT observation
- GRB 121027A: MAXI/GSC detection 40 minutes after the Swift Trigger
- GRB 121027A: Swift detection of a burst
- Swift Quick-look and HEASARC will be offline for 24 hours this weekend
- GRB 121024A: optical observations
- GRB 121024A: EVLA Detection
- Swift-BAT trigger 536502 is not astrophysical
- GRB 121024A: Swift/UVOT Observations
- GRB 121024A: CARMA 3mm Detection
- GRB 121024A: Swift-BAT refined analysis
- GRB 121024A: GMG optical observation
- GRB 121024A: MITSuME Ishigakijima upper limits
- GRB 121024A: MITSuME Okayama Optical upper limits
- GRB 121025A: MAXI/GSC detection
- GRB 121024A: Enhanced Swift-XRT position
- GRB 121024A: PAIRITEL NIR Detection
- GRB 121024A: Swift-XRT refined Analysis
- GRB 121024A: GROND Detection of the Optical/NIR Afterglow
- GRB 121024A: VLT/X-shooter redshift
- Skynet PROMPT/Dolomiti observations of GRB121024A
- GRB 121024A: BOOTES-1B optical detection
- GRB 121024A: TAROT Calern observatory optical detection of a bright counterpart
- GRB 121024A: Swift detection of a burst with an optical counterpart
- Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
- GRB 121011A: early optical light curve
- GRB 121017A: Swift/UVOT Upper Limits
- GRB 121017A: Swift-XRT refined Analysis
- GRB 121017A: GROND Observations
- GRB 121017A: Swift-BAT refined analysis
- GRB 121017A: Enhanced Swift-XRT position
- GRB 121017A: 1.23m CAHA R-band observations
- GRB 121017A optical observations
- GRB 121017A: BOOTES-2/TELMA observations
- GRB 121017A: Swift detection of a burst
- GRB 121011B: Suzaku WAM observation of the prompt emission
- GRB 121011A Suzaku WAM observation of the prompt emission
- GRB 121012A: Fermi GBM detection
- PdB IRAM observation of GRB 121011A
- Konus-Wind observation of GRB 121011B
- GRB 121014A: Swift-BAT refined analysis
- GRB 121011A: WSRT radio observation
- GRB 121014A: Swift detection of a burst
- INTEGRAL Alert n.6678: NOT A GRB
- GRB 121011A: optical observations
- GRB 121011A: Swift/UVOT Detection
- IPN Triangulation of short hard GRB 121011B
- GRB 121011A: NOT redshift retraction
- GRB 121011A: misprint in GCNC 13854
- GRB 121011A: Fermi GBM observation
- GRB 121011A: Fermi-LAT detection of a burst
- Swift-BAT trigger 535733 is not astrophysical
- GRB 121011A: Swift-XRT refined Analysis
- GRB 121011A: NOT optical observations
- GRB 121011A: optical observations
- GRB 121011A: MASTER-Net bell light curve
- GRB 121011A: TNG optical observations
- GRB 121011A, Swift-BAT refined analysis
- Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747)
- GRB 121011A: Enhanced Swift-XRT position
- Planned XMM-Newton and IRAM observation of GRB 121011A
- GRB 121011A: MASTER-Net early OT light curve
- GRB121011A : Xinglong TNT optical observation
- GRB 121011A: MITSuME Okayama Optical Observation
- GRB 121011A: Swift detection of a burst with optical afterglow
- Trigger 535747: Swift detection of an outburst from SGR1806-20
- Trigger 535733: Swift possible detection of SAX J1828.5-1037
- GRB 120927A: optical upper limit
- GRB 120804A: Late-time Chandra observation
- GRB 121001A: GROND Afterglow Confirmation
- GRB 121001A: Swift/UVOT Upper Limits
- GRB 121001A: Swift-XRT refined Analysis
- GRB 121001A: Enhanced Swift-XRT Position
- Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
- Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA.
- GRB 121001A: MASTER optical observations
- GRB 121001A: possible optical counterpart
- Swift Trigger 535026: ROTSE-III Optical Limits