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"21455 results found.
- GRB 230427A: Swift-XRT refined Analysis
- GRB 230427A: GIT optical upper limit
- GRB 230427A: Bassano Bresciano Observatory upper limit
- GRB 230427A : OHP/T193 optical 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)
- GRB 230414B: Montarrenti Observatory late time optical afterglow detection
- GRB 230414B: Lulin 40cm-SLT optical limit
- GRB 230414B: Bassano Bresciano Observatory optical observations
- GRB 230414B: AbAO optical observations
- GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
- GRB 230414B: Swift-XRT refined Analysis
- GRB 230414B: Dabancheng/GHOST optical observations
- GRB 230414B: SAO RAS optical observations
- GRB 230414B: Enhanced Swift-XRT position
- GRB 230414B: 1.3m DFOT Optical observations
- GRB 230414B: GROWTH India Telescope afterglow confirmation
- GRB 230414B: Nanshan/HMT optical afterglow detection
- GRB 230414A: Mondy optical afterglow candidate
- Swift GRB 230414B: Global MASTER-Net observations report
- GRB 230414B: Prompt enhanced Swift-XRT position
- GRB 230414B: Swift detection of a burst
- GRB 230328B: redshift lower limit estimating
- GRB 230409B: Mondy optical upper limit
- GRB 230409B: Swift-XRT refined Analysis
- GRB 230409B: Swift-BAT refined analysis
- Swift GRB 230409B: Global MASTER-Net observations report
- GRB 230409B: Swift/UVOT Detection
- GRB 230409B: Enhanced Swift-XRT position
- GRB 230409B: Swift detection of a burst
- GRB 230405B: VZLUSAT-2 detection
- Konus-Wind detection of GRB 230405B
- GRB 230405B: AGILE detection
- GRB 230405B: Swift-XRT refined Analysis
- GRB 230405B: Fermi GBM Observation
- GRB 230405B: MeerLICHT upper limits
- GRB 230405B: Swift/UVOT Upper Limits
- GRB 230405B: AstroSat CZTI detection
- GRB 230405B: Enhanced Swift-XRT position
- Swift GRB 230405B: Global MASTER-Net observations report
- GRB 230405B: Prompt enhanced Swift-XRT position
- GRB 230405B: Swift detection of a burst
- GRB 230307A: Chandra late-time detection of the X-ray afterglow
- GRB 230228A: detection by GTC of the potential host galaxy
- GRB 230328B: Swift/UVOT Detection
- GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
- GRB 230328B: CAHA 2.2m/CAFOS detection
- GRB 230328B: 3.6m DOT multiband optical observation
- Konus-Wind detection of GRB 230328B
- GRB 230328B: GRBAlpha detection
- GRB 230328B: Swift-BAT refined analysis
- GRB 230328B: Nanshan/NEXT 2nd optical observation
- GRB 230328B NUTTelA-TAO / BSTI Early Measurements
- GRB 230328B: Liverpool Telescope afterglow detection
- GRB 230328B: GIT optical follow-up
- GRB 230328B: OASDG optical observations
- GRB 230328B: Nanshan/NEXT optical upper limit
- GRB 230328B: Swift-XRT refined Analysis
- GRB 230328B: AstroSat CZTI detection
- GRB 230328B: Fermi GBM observation
- GRB 230328B: Mondy, AbAO and Kitab optical observations
- GRB 230328B: Enhanced Swift-XRT position
- GRB 230328B: Mondy optical afterglow confirmation
- GRB 230328B: Swift detection of a burst with an optical afterglow
- GRB 230325A: Swift-BAT refined analysis
- GRB 230325A: Swift/UVOT Upper Limits
- GRB 230325A: X-shooter optical afterglow and redshift
- GRB 230325A: Swift-XRT refined Analysis
- GRB 230322B: Swift-BAT refined analysis