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"19549 results found.
- Correction to GCN Circular 23663: GRB 190109A: Swift UVOT Upper Limits
- GRB 190110A: Fermi GBM detection
- GRB 190109B: Fermi GBM observation
- GRB 190109B: Swift/UVOT Upper Limits
- GRB 190109A: Swift/UVOT Upper Limits
- GRB 190106A: Liverpool Telescope observations
- GRB 190109B: COATLI Optical Observations
- GRB 190109B: Mondy optical upper limit
- GRB 190109B: Enhanced Swift-XRT position
- GRB 190109B: Swift-XRT observations
- INTEGRAL Weak#8189: AROMA-N Optical Observation
- GRB190109A: MITSuME Akeno optical upper limits
- GRB 190109B: Swift detection of a burst
- IPN triangulation of GRB 190103A (long)
- GRB 190109A: Enhanced Swift-XRT position
- GRB 190109A: Swift detection of a burst
- IceCube-190104A: Swift-XRT observations
- GRB 190106A: OASDG optical observations
- GRB 190106A: Swift/UVOT Detection
- GRB 190106A: Bassano Bresciano Observatory optical detection
- Fermi GBM Observations of IceCube-190104A
- GRB 190106A: Enhanced Swift-XRT position
- GRB 190106A: GMG detection
- GRB 190106A: Swift detection of a burst with an optical counterpart
- Fermi LAT Gamma-ray Observations of IceCube-190104A
- GRB 190103B: Bassano Bresciano observatory upper limit
- GRB 190103B: Enhanced Swift-XRT position
- GRB 190103B: Swift detection of a burst
- GRB 181228A: Mondy and AbAO optical upper limits
- GRB 181225A: further Swift-XRT observations
- GRB 181228A: possible NOT optical detection
- GRB 181228A: Xinglong-2.16m optical upper limit
- Swift Trigger 880127 is not a GRB
- GRB 181222B: Swift follow-up observations of MASTER optical transient J204928.79+245744.0
- GRB 181228A: Swift/UVOT Upper Limits
- GRB 181228A: TSHAO optical upper limit
- GRB 181228A: Fermi GBM observation
- GRB 181228A: REM NIR detection
- GRB 181228A: Enhanced Swift-XRT position
- GRB 181225A: KAIT Follow-Up Observations with Upper Limit
- GRB 181228A: Swift detection of a burst
- GRB 181222B: Swift ToO observations
- GRB 181225A: Swift observations and X-ray candidate afterglow
- GRB 181225A: Swift ToO observations
- GRB 181222B: Global MASTER Net observations of the short bright Fermi GRB error box.
- GRB 181222B : Fermi GBM detection
- Swift Trigger 878504 is not astrophysical
- GRB 181213A: Swift/UVOT Observations
- GRB 181213A: Mondy optical observations
- GRB 181213A: continued TSHAO optical observations
- GRB 181213A: AbAO optical observations
- GRB 181213A: HMM-0.5m, NEXT-0.6m, CNEOST-1m optical observations
- GRB 181213A: Enhanced Swift-XRT position
- IPN Triangulation of GRB 181212A (long)
- GRB 181213A: Swift-BAT refined analysis
- GRB 181213A : TSHAO optical observations
- GRB 181213A: Swift-XRT observations
- GRB 181212A: Fermi GBM Detection
- GRB 181126B: KAIT Follow-Up Observations of a Fermi Short GRB (Trigger 564897175)
- GRB 181203A: GROND detection of the afterglow
- GRB 181205A: a long GRB detected by INTEGRAL
- GRB181201A: Optical afterglow measurements by GROWTH-India
- Swift Trigger 874754 is likely not an astrophysical event
- Fermi-GBM Observations During Four New GW-Detected BBH Mergers (Correction)
- Fermi-GBM Observations During Four New GW-Detected BBH Mergers
- GRB 181203A: Swift/UVOT Upper Limits
- GRB 181201A: Continued GROND observations show that afterglow is still bright
- GRB181201A: GOTO optical observations
- GRB 181203A: Swift-XRT refined Analysis
- GRB 181201A: Swift/UVOT Detection
- GRB 181202A: Swift/UVOT Detection
- GRB 181202A: RATIR Optical and NIR Observations
- GRB 181203A: Enhanced Swift-XRT position
- GRB 181203A: Swift detection of a burst
- GRB 181201A: Further COATLI Optical Monitoring
- GRB 181201A: GROND detection of the afterglow and redshift upper limit of z < 3
- GRB 181201A: optical observations in Chilescope observatory
- GRB 181202A: Enhanced Swift-XRT position
- GRB 181202A: Swift detection of a burst with an optical counterpart
- GRB 181201A: COATLI Optical Detection
- GRB 181201A: Fermi-LAT detection
- GRB 181201A: Zeiss-1000/CrAO optical observations
- GRB 181201A: optical observations in SAAO
- GRB 181201A: iTelescope optical afterglow detection
- GRB 181201A: Swift-XRT afterglow detection
- GRB 181201A: Swift ToO observations
- Short-duration GRB 181121.4: MASTER-Tavrida possible OT detection near the PGC galaxy during large Fermi error box inspection
- GRB 181126A: Swift-BAT refined analysis
- GRB 181123B: Keck further near-infrared imaging
- GRB 181126A: Swift/UVOT Upper Limits
- GRB 181126A deep Gemini imaging
- GRB 181126A: Enhanced Swift-XRT position
- GRB 181126A: Swift detection of a burst
- GRB 181123B: Swift-BAT lag analysis and search for extended emission
- GRB 181123B: Keck near-infrared imaging
- GRB 181123B: Gemini-North optical detection
- GRB 181123B: Swift/UVOT Upper Limits
- GRB 181123B: Enhanced Swift-XRT position
- GRB 181123B: Swift detection of a short burst
- Swift Trigger 872470: further Swift analysis