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"25891 results found.
- GRB 230307A: JWST second-epoch observations
- GRB 230506C: Swift-XRT refined Analysis
- GRB 230506C: Swift-BAT refined analysis
- GRB 230506B: Swift-BAT refined analysis
- GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
- GRB 230506B: LCOGT Optical Upper Limits
- GRB 230506C: Swift/UVOT Upper Limits
- GRB 230506C: NUTTelA-TAO / BSTI Early Optical 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 230430A: A short GRB from a neutron star merger
- 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: OSIRIS+/GTC observations
- GRB 230427A: Swift-XRT refined Analysis
- GRB 230427A: GIT optical upper limit
- GRB 230427A: Bassano Bresciano Observatory upper limit
- GRB 230427A: GMG 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 221009A: Late-time JWST Observations and Detection of Supernova Emission
- GRB 230421A: Fermi GBM observation
- Konus-Wind detection of GRB 230418A
- GRB 230420A: Swift/UVOT Upper Limits
- GRB 230421: Swift/BAT-GUANO arcminute localization
- GRB230420A: VLT optical observation
- 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: Nickel and KAIT telescope optical observations
- 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 230414B: 3.6m DOT Optical observations, slow decay at early epochs
- 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: Redshift from OSIRIS/GTC
- 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: slow optical light curve decay
- 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 (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
- 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