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.
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"19600 results found.
- GRB 230614B: Fermi GBM Observation
- GRB 230614B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230606A: LCOGT Optical Observations
- GRB 230606A: Swift-BAT refined analysis
- GRB 230606A: Gaoyazi/GOT optical upper limit
- GRB 230606A: Fermi GBM Observation
- GRB 230606A: BOOTES-5/JGT optical upper limit
- GRB 230606A: Swift-XRT refined Analysis
- GRB 230606A: Swift/UVOT Upper Limits
- GRB 230606A: Enhanced Swift-XRT position
- GRB 230606A: Swift detection of a burst
- GRB 230510A: Swift-BAT refined analysis
- GRB 230523B: GRBAlpha detection
- GRB 230523B: Name correction from GCN Circular 33859
- GRB 230523A: Swift/BAT-GUANO detection of a short hard burst
- LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for MeerLICHT candidates: AT2023ixg and AT2023iyb
- IPN triangulation of GRB 230518A (short)
- LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for Swope candidates: SSS23a, SSS23b and SSS23c
- GRB 230518A: Fermi GBM Observation
- GRB 230518A: Swift/BAT-GUANO detection
- LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
- Improved IPN triangulation of GRB 230512A
- IPN triangulation of GRB 230512A
- GRB 230510A: GRBAlpha detection
- GRB 230512A: Swift-XRT observations
- GRB 230512A: Tiled Swift observations
- GRB 230512A: Fermi-LAT detection
- GRB 230510A: GIT optical upper limits
- GRB 230510A: LCOGT Optical Upper Limit
- GRB 230510A: Swift/UVOT Observations
- GRB 230510A: Fermi GBM detection
- GRB 230510A: Gaoyazi/GOT optical upper limit
- GRB 230510A: CALET Gamma-Ray Burst Monitor detection
- GRB 230510A: Nanshan/NEXT optical afterglow detection
- GRB 230506B: Fermi GBM detection
- GRB 230510A: Swift-XRT refined Analysis
- GRB 230510A: Enhanced Swift-XRT position
- GRB 230506C: Fermi GBM detection
- GRB 230510A: Swift detection of a burst
- GRB 230506B: Swift/UVOT further analysis
- GRB 230506C: Swift-XRT refined Analysis
- GRB 230506C: Swift-BAT refined analysis
- GRB 230506B: Swift-BAT refined analysis
- GRB 230506B: LCOGT Optical Upper Limits
- GRB 230506C: Swift/UVOT Upper Limits
- GRB 230506B: Swift-XRT refined Analysis
- GRB 230506C: Swift-XRT analysis
- GRB 230506C: Candidate afterglow observation by D50
- GRB 230506C: TSHAO possible afterglow candidate
- GRB 230506B: Swift/UVOT Detection
- GRB 230506C: Swift detection of a burst
- Swift GRB230506.71: Global MASTER-Net observations report
- GRB 230506B: Swift detection of a burst
- GRB 230506B: MASTER optical observations
- GRB 230506B: Swift detection of a burst
- GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
- GRB 230427A: Swift-BAT refined analysis
- GRB 230420A: AROMA-N Optical Upper Limit
- GRB 230427A: NOT optical upper limit
- GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
- GRB 230427A: Swift/UVOT Detection
- GRB 230427A: Gaoyazi/GOT optical upper limit
- GRB 230427A: Nanshan/HMT optical upper limit
- GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
- GRB 230427A: Swift-XRT refined Analysis
- GRB 230427A: GIT optical upper limit
- GRB 230427A: Bassano Bresciano Observatory upper limit
- GRB 230427A: BOOTES-5/JGT afterglow detection
- GRB 230423A(trigger #1165354): Swift-BAT refined analysis
- GRB 230427A: AKO Upper Limit
- Swift GRB230427.44: Global MASTER-Net observations report
- GRB 230427A: MITSuME Akeno optical upper limits
- GRB 230427A: Enhanced Swift-XRT position
- GRB 230427A: Swift detection of a burst with an optical counterpart
- GRB 230423A: Swift/UVOT Upper Limits
- GRB 230423A: Swift-XRT refined Analysis
- GRB 230423A: Swift-XRT afterglow detection
- Swift Trigger 1165354 is probably not a GRB
- GRB 230421A: Fermi GBM observation
- Konus-Wind detection of GRB 230418A
- GRB 230420A: Swift/UVOT Upper Limits
- GRB 230421: Swift/BAT-GUANO arcminute localization
- GRB 230420A: Swift-BAT refined analysis
- GRB 230420A: Swift-XRT refined Analysis
- GRB 230420A: MITSuME Akeno optical observation
- GRB 230420A: NOT optical afterglow confirmation
- GRB 230420A: Gaoyazi/GOT optical upper limit
- GRB 230420A: BOOTES-5/JGT optical afterglow detection
- GRB 230420A: LCOGT Optical Upper Limit
- GRB 230420A: Enhanced Swift-XRT position
- IPN triangulation of GRB 230418A (short)
- GRB 230420A: Swift detection of a burst
- GRB 230418A: AstroSat CZTI detection
- GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230414B Swift-BAT refined analysis
- GRB 230415A: Fermi GBM detection
- GRB 230414B: Swift/UVOT Detection
- GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
- GRB 230415A: Swift/BAT-GUANO detection
- GRB 230307A: iTelescope optical upper limit (likely)