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 160607A: Enhanced Swift-XRT position
- GRB 160607A: Swift detection of a bright burst
- GRB 160530A: further Swift-XRT follow-up observations
- Fermi GBM trigger 486907024/160606498 is not a GRB
- Trigger 689353: Swift detection of a transient near Sgr A*
- GRB 160601A: AbAO optical observations
- GRB 160601A: Discovery Channel Telescope Limits
- GRB 160601A: Swift/UVOT Upper Limits
- GRB 160601A: MITSuME Akeno optical upper limits
- GRB 160601A: Swift-BAT refined analysis
- Fermi GBM trigger 486562774/160602514 is not a GRB
- GRB160601A: Gemini Imaging
- GRB 160601A: GTC observations confirming transient source decay
- GRB 160601A: Mondy optical observations, photometry of NOT sources
- GRB160601A: Kanata Telescope I- and Ks-bands upper limits
- GRB160601A: NOT afterglow confirmation
- GRB 160530B CALET Gamma-Ray Burst Monitor detection
- GRB 160601A: Swift-XRT refined Analysis
- GRB160601A: NOT detection of an afterglow candidate
- GRB 160601A: Enhanced Swift-XRT position
- GRB 160601A: Mondy optical observations
- GRB 160601A: MITSuME Okayama Ks-band upper-limit
- GRB 160530A: Swift follow-up and X-ray afterglow candidate
- GRB 160601A: MITSuME Okayama upper limits
- GRB 160601A: MASTER-Net observations
- GRB 160601A: Swift detection of a short hard burst
- Konus-Wind observation of GRB 160530A
- IPN Triangulation of GRB 160530A
- GRB 160525B: MITSuME Akeno optical upper limits
- GRB 160530B: Fermi GBM Detection
- GRB 160530A: discovery with the Compton Spectrometer and Imager
- GRB 160530A: Tiled Swift observations
- GRB 160525C: CALET Gamma-Ray Burst Monitor detection
- GRB 160525B: Mondy optical upper limit
- GRB 160525B: Khureltogot optical upper limit
- GRB 160525B: Swift-BAT refined analysis
- GRB 160525B: Swift-XRT refined Analysis
- GRB 160525B: Nanshan optical upper limit
- GRB 160525B: Swift/UVOT Detection
- GRB 160521B: Swift-XRT afterglow detection
- GRB 160525B: Enhanced Swift-XRT position
- Konus-Wind observation of GRB 160521B
- GRB 160525A: Swift-BAT refined analysis
- GRB 160525B: Prompt enhanced Swift-XRT position
- GRB 160525B: Swift detection of a burst
- GRB 160525A: Swift detection of a probable burst
- Correction - Fermi/GBM trigger 160523919 is a GRB
- GRB 160521B: Theoretical estimate of the redshift and urgent need for further x-ray observations
- The nature of the Fermi/GBM trigger 160523919 is unknown.
- GRB 160425A: SMARTS late-time observations
- GRB 160327A: 15 GHz upper limits from AMI
- GRB 160321A: 15 GHz upper limits from AMI
- GRB 160314A: 15 GHz upper limits from AMI
- GRB 160313A: 15 GHz upper limits from AMI
- GRB 160521B: Swift/UVOT Upper Limits
- GRB 160521B: Swift-XRT observations
- Another Swift detection of SGR 1935+2154 (trigger #687124)
- Swift detection of SGR 1935+2154
- GRB 160521B: Swift ToO observations
- GRB 160521B: Fermi-LAT detection
- GRB 160521B: Fermi GBM detection
- GRB 160521A: a long GRB detected by INTEGRAL
- GRB 160519A: Swift-BAT refined analysis
- Swift-BAT trigger 686845 was due to noise near a known source
- GRB 160519A: Fermi GBM detection
- Konus-Wind observation of a bright burst from SGR 1935+2154
- FERMI GBM bursts from the magnetar SGR 1935+2154
- GRB 160519A: Swift detection of a burst
- SGR 1935+2154: AbAO optical upper limit
- Fermi GBM triggers of SGR 1935+2154
- Trigger 686761: Swift detection of a bright burst from SGR 1935+2154
- Fermi GBM trigger 485205628 /160517806 is not a GRB
- Fermi GBM trigger 485124591/160516868 is not a GRB
- Trigger 686443: Swift detection of SGR 1935+2154
- Fermi GBM trigger 484906918/160514349 is not a GRB
- GRB 160509A: Further VLA Observations
- FACT follow-up of the IceCube event 160427A
- Interplanetary Network Search for IceCube 160427A
- GRB 160509A MASTER-NET observations
- GRB 160509A: CALET Gamma-Ray Burst Monitor detection
- GRB 160509A: non-observation of VHE emission with HAWC
- GRB 160508A: CALET Gamma-Ray Burst Monitor detection
- GRB 160509A: TLS Tautenburg Afterglow Detection
- GRB 160509A: Further Swift/UVOT Observations
- GRB 160509A Gemini North redshift
- Fermi GBM trigger 484574960/160510506 is not a GRB
- Konus-Wind observation of GRB 160509A
- GRB 160509A: DCT Imaging / Afterglow Confirmation
- GRB 160509A: MAXI/GSC refined analysis
- GRB 160509A: VLA Detection
- GRB 160509A: Fermi-LAT refined analysis
- GRB 160509A: Swift/UVOT Upper Limit
- GRB 160509A: Fermi GBM Detection
- GRB 160509A Gemini North candidate afterglow
- GRB 160509A: optical observations
- GRB 160509A: Swift-XRT afterglow detection
- GRB 160509A: Preliminary XRT positon
- GRB 160509A: Tiled Swift observations
- Correction to GCN 19404; GRB 160509A: MAXI/GSC detection
- GRB 160227A: MAXI/GSC detection