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"19361 results found.
- GRB 240421B: AstroSat CZTI detection
- GRB240421B: Zadko Observations
- Swift GRB 240421B: Global MASTER-Net observations report
- GRB 240421B: Fermi GBM Observation
- GRB 240421B: Swift-XRT refined Analysis
- GRB240421B: BOOTES-5/JGT optical upper limit
- GRB 240421B: Swift/UVOT Upper Limits
- GRB 240421B: Enhanced Swift-XRT position
- GRB 240421B: Swift detection of a burst
- GRB240419A: Skynet Optical Afterglow Analysis
- GRB 240419B: Swift/UVOT Upper Limits
- GRB 240419A: Swift/UVOT Upper Limits
- GRB 240419B: Swift-XRT refined Analysis
- Swift GRB 240419B: Global MASTER-Net observations report
- GRB 240419B: Enhanced Swift-XRT position
- Swift GRB 240419A: Global MASTER-Net observations report
- GRB 240418A: Swift/UVOT Upper Limits
- GRB 240419A: Swift-XRT refined Analysis
- GRB 240418A: Swift-XRT refined Analysis
- GRB 240419B: Swift detection of a burst
- GRB 240411B: Swift/UVOT Detection
- GRB240418A: YAHPT Upper Limits
- GRB 240419A: Enhanced Swift-XRT position
- GRB 240419A: Prompt enhanced Swift-XRT position
- GRB 240419A: Swift detection of a burst
- GRB 240418A: TSHAO Zeiss-1000 optical upper limit
- GRB 240418A: Enhanced Swift-XRT position
- Swift GRB240418.85: Global MASTER-Net observations report
- GRB 240418A: Swift detection of a burst
- Improved IPN triangulation of GRB 240411A
- GRB 240415A: Glowbug gamma-ray detection
- GRB 240414A: Glowbug gamma-ray detection
- GRB 240415B: GECAM-B detection
- GRB 240415A: Swift-BAT refined analysis
- GRB 240411A: Glowbug gamma-ray detection
- GRB 240414A: Swift-BAT refined analysis
- GRB 240414A: AbAO optical upprer limit
- GRB 240415A: Swift/UVOT Detection
- GRB 240415A: Fermi GBM Observation
- GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
- GRB 240415A: Enhanced Swift-XRT position
- GRB 240415B: Swift ToO observations
- GRB 240415B: Swift/BAT-GUANO Correction
- GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 240414A: Fermi GBM Observation
- GRB 240414A: Swift/UVOT Detection
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Mondy optical observations
- GRB 240415A: Prompt Swift-XRT observations
- GRB 240415A: Swift detection of a burst
- GRB 240414A: Swift-XRT refined Analysis
- GRB 240414A: Enhanced Swift-XRT position
- GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- GRB 240414A: Skynet Optical Afterglow Observations
- Swift GRB 240414A: Global MASTER-Net observations report
- IPN triangulation of GRB 240410A
- IPN triangulation of GRB 240411A
- GRB 240414A : MITSuME Akeno optical upper limits
- GRB 240414A: Swift detection of a burst
- GRB 240411B: Swift-BAT refined analysis
- GRB 240411B: Swift-XRT refined Analysis
- GRB 240411B: 1.3m DFOT Optical observations
- GRB 240411B: Enhanced Swift-XRT position
- GRB 240411B: Swift detection of a burst
- EP240408A: MASTER optical observations
- EP240408a: GROND detection of a candidate counterpart
- EP240408a: Swift follow-up observation
- Swift Trigger 1220736: detection of 4U 1543-62.
- Swift satellite resumes pointed science observations
- GRB 240318A: Fermi GBM Observation
- Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
- GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
- GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
- GRB 240317B: Swift/BAT-GUANO Angular Error Correction
- GRB 240317B: Fermi GBM Observation
- Swift satellite in safe mode
- GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
- Einstein Probe detected of a fast X-ray transient EP240315a
- GRID detection of GRB 240306A
- Swift Triggers 1220155, 1220156, 1220157, 1220158, 1220160 and 1220161 were not astrophysical
- Swift Triggers 1220093, 1220094, 1220095 and 1220096 are not astrophysical
- Swift Triggers 1220090, 1220091 and 1220092 are not astrophysical
- Swift triggers 1219917, 1219917 and 1219922 were not astrophysical
- Swift Trigger 1219909 and 1219910 are not a astrophysical
- Swift Trigger 1219905 is not a GRB
- Swift Trigger 1219874 is not astrophysical
- Swift GRB240309.61: Global MASTER-Net observations report
- Swift Trigger 1219325 is not a GRB
- GRB 240306A: Fermi GBM observation
- Konus-Wind detection of GRB 231118A
- GRB 240306A: AstroSat CZTI detection
- GRB 240306A: Swift/BAT-GUANO detection of a burst
- GRB 240305A: Fermi GBM observation
- Swift GRB240305.18: Global MASTER-Net observations report
- Swift GRB240305.16: Global MASTER-Net observations report
- GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 240218A: Chandra Detection and Jet Break Confirmation
- Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
- Swift Trigger 1218696: Another trigger on Swift J151857.0-572147