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"- GRB160228A: Further analyses on spectral lag and extended emission
- GRB 160228A: Mondy optcial observations
- GRB 160228A: RATIR Optical and NIR Observations
- GRB 160228A: MASTER-Amur prompt observations
- GRB 160228A: Swift-XRT refined Analysis
- GRB 160227A: MASTER prompt OT Detection and LC
- GRB 160227A: AROMA-N Optical Observation
- GRB 160228A: GROND Afterglow Candidate
- GRB 160228A: Swift-BAT refined analysis
- GRB 160228A: optical observations
- GRB 160227B: Fermi GBM detection
- GRB 160228A: Enhanced Swift-XRT position
- GRB 160227A: NOT redshift
- GRB 160228A: Prompt enhanced Swift-XRT position
- GRB 160228A: Swift detection of a burst
- GRB 160227A, Swift-BAT refined analysis
- GRB 160227A: Swift-XRT refined Analysis
- GRB 160227A: Enhanced Swift-XRT position
- GRB 160227A: MAXI/GSC detection
- GRB 160225A: TSHAO optical afterglow detection
- GRB 160227A: ISON-Kislovodsk optical observation
- GRB 160227A: Mt. Terskol observatory optical observation
- GRB 160227A: MASTER OT Detection
- GRB 160227A: Swift detection of a burst with an optical counterpart
- GRB 160225A: LOAO optical upper limit
- GRB 160225B: Fermi GBM detection
- IPN Triangulation of GRB 160225B
- GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
- GRB 160225A: Continued RATIR Optical and NIR Observations
- GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 detection
- GRB 160225A: Swift-BAT refined analysis
- Fermi GBM trigger 478156376/16022621 is not a GRB
- GRB 160225A: MASTER-Amur observations
- GRB 160225A: RATIR Optical and NIR Observations
- GRB 160225A: Swift/UVOT Upper Limits
- GRB 160225A: Xinglong TNT optical observation
- GRB 160223B: CALET Gamma-Ray Burst Monitor detection
- GRB 160225A: Swift-XRT refined Analysis
- GRB 160225A: NOT optical observations
- GRB 160225A: WHT LIRIS observations
- GRB 160225A: MITSuME Okayama Optical Observation
- GRB 160225A: MITSuME Akeno Optical Observation
- GRB 160223A: RATIR Optical and NIR Observations
- GRB 160225A: TSHAO optical upper limit
- GRB 160225A: Enhanced Swift-XRT position
- GRB 160225A: MASTER-Amur early observations
- GRB 160225A: Swift detection of a burst
- GRB 160223A: Swift-XRT afterglow detection
- GRB 160221A: Swift-XRT afterglow detection
- GRB 160223A: AbAO optical observations
- Swift trigger 675784 is probably not an astrophysical source
- Konus-Wind observation of GRB 160219A
- GRB 160223B: MASTER-Amur early observations
- Fermi GBM trigger 477460274/160218161 is not a GRB
- Fermi GBM trigger 477985003/160224234 is not a GRB
- GRB 160223A: Swift-BAT refined analysis
- GRB 160223B: Khureltogot optical observations
- GRB 160223A: Fermi GBM observation
- GRB 160223B: Swift-XRT observations
- GRB 160223B: LCOGT-FTN optical observations
- GRB 160223B: Fermi GBM observation
- GRB 160223B: Swift ToO observations
- GRB 160223B: A long GRB detected by INTEGRAL
- GRB 160223A: GROND optical/NIR afterglow
- GRB 160223A: Swift detection of a burst
- GRB 160221A: Fermi GBM observation
- LVC GW 150914: TAROT/TZAC Final analysis correction
- GRB 160221A: GROND upper limits
- Correction to the title of Swift GCN 19051
- GRB 160220B: Further GROND Observations
- Further Swift/UVOT observations of GRB 160220B
- GRB 160221A: Swift-XRT observations
- GRB 160221A: MASTER-SAAO early observations
- LVC GW 150914: TAROT/TZAC Final analysis
- GRB 160221A: Swift ToO observations
- GRB 160221A: A long GRB detected by INTEGRAL
- Konus-Wind observation of GRB 160220B
- Swift trigger 674752 is likely due to a noise fluctuation
- GRB 160220B: Swift-BAT refined analysis
- GRB 160220B: GROND Observations
- GRB 160219A: Fermi GBM detection
- GRB 160220A: nIR observations at AAT
- GRB 160220A: Swift-XRT refined Analysis
- GRB 160220A: Swift-BAT refined analysis
- GRB160220B: Swift/UVOT observations
- GRB 160220B: Swift-XRT refined Analysis
- IPN Triangulation of GRB 160219A (short/hard)
- LIGO/Virgo GW150914
- GRB160220B: Enhanced Swift-XRT position
- GRB160220A: Swift/UVOT observations
- Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
- GRB 160220A: TAROT Calern and TAROT La Silla observatory optical observations
- GRB 160220B: Swift detection of a burst
- GRB 160220A: MASTER-Amur observations
- GRB 160220A: GROND Optical/NIR Upper Limits
- GRB 160220A: Fermi GBM observation
- GRB 160220A: Enhanced Swift-XRT position
- GRB 160220A: Swift-XRT observations
- GRB 160220A: Swift detection of a burst
- LIGO/Virgo GW150914: BOOTES-3 simultaneous imaging